WorldWideScience

Sample records for advanced gas cooled

  1. Advanced Combustor Liner Cooling Technology for Gas Turbines

    Directory of Open Access Journals (Sweden)

    Aspi R. Wadia

    1988-10-01

    Full Text Available This paper briefly reviews some of the work on advanced liner cooling techniques - specificially laminated porous wall cooling, angled-multihole (effusion cooling and composite metal matrix liner cooling. The concept definition, heat transfer design procedure and design problems including key materials and fabrication considerations associated with each basic concept will be reviewed. Published rig and engine experience of aircraft engine manufacturers and research organizations will be cited. Some logical extensions of the current liner cooling schemes are suggested for future applications.

  2. Advanced gas cooled nuclear reactor materials evaluation and development program

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Results of work performed from January 1, 1977 through March 31, 1977 on the Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Process Heat and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (impure Helium), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes progress to date on alloy selection for VHTR Nuclear Process Heat (NPH) applications and for DCHT applications. The present status on the simulated reactor helium loop design and on designs for the testing and analysis facilities and equipment is discussed.

  3. Analysis of the horizontal flow in the advanced gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Y. [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); He, S., E-mail: s.he@sheffield.ac.uk [Department of Mechanical Engineering, University of Sheffield, Sheffield S1 3JD (United Kingdom); Ganesan, P. [Department of Mechanical Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Gotts, J. [EDF Energy, Barnwood, Gloucester GL4 3RS (United Kingdom)

    2014-06-01

    Highlights: • CFD is used to assess the effect of horizontal flows in AGRs. • The horizontal flows can reduce the graphite brick temperature significantly. • Such effects are not taken into consideration in current engineering calculations. • There might be flow instabilities when the fuel channel flow is very low but horizontal flows reduce its possibility. - Abstract: The purpose of the paper is to report a computational investigation of horizontal flows in the UK advanced-gas-cooled reactor (AGR) by using computational fluid dynamics with ANSYS FLUENT. The study is relevant to practical issues encountered in some AGR stations currently in operation in the UK. It is carried out using a comparative approach based on the results of two contrasting models: one simulating the full effect of the cross flow, the other simulating the simplified approach currently employed by the industry which neglects the momentum of the horizontal cross flow. The study reveals that the horizontal cross flow plays a significant role in the cooling of the moderator brick, while the axial variation of the brick geometry also significantly changes the distribution of the temperature within the brick. It is also found that under some circumstances the so-called horizontal inter-brick leakage (HIBL) flow could influence the cooling performance in the narrow gaps, resulting in a local hot spot. Furthermore, there may be flow instabilities in the flows in AGR fuel channels due to the interactions between the flow in the main arrowhead flow passages and that in some narrow passages connected to it, but the influence on the brick temperature is negligible. Horizontal cross flow has an effect of reducing such instabilities.

  4. Impingement jet cooling in gas turbines

    CERN Document Server

    Amano, R S

    2014-01-01

    Due to the requirement for enhanced cooling technologies on modern gas turbine engines, advanced research and development has had to take place in field of thermal engineering. Impingement jet cooling is one of the most effective in terms of cooling, manufacturability and cost. This is the first to book to focus on impingement cooling alone.

  5. Axisymmetric whole pin life modelling of advanced gas-cooled reactor nuclear fuel

    Science.gov (United States)

    Mella, R.; Wenman, M. R.

    2013-06-01

    Thermo-mechanical contributions to pellet-clad interaction (PCI) in advanced gas-cooled reactors (AGRs) are modelled in the ABAQUS finite element (FE) code. User supplied sub-routines permit the modelling of the non-linear behaviour of AGR fuel through life. Through utilisation of ABAQUS's well-developed pre- and post-processing ability, the behaviour of the axially constrained steel clad fuel was modelled. The 2D axisymmetric model includes thermo-mechanical behaviour of the fuel with time and condition dependent material properties. Pellet cladding gap dynamics and thermal behaviour are also modelled. The model treats heat up as a fully coupled temperature-displacement study. Dwell time and direct power cycling was applied to model the impact of online refuelling, a key feature of the AGR. The model includes the visco-plastic behaviour of the fuel under the stress and irradiation conditions within an AGR core and a non-linear heat transfer model. A multiscale fission gas release model is applied to compute pin pressure; this model is coupled to the PCI gap model through an explicit fission gas inventory code. Whole pin, whole life, models are able to show the impact of the fuel on all segments of cladding including weld end caps and cladding pellet locking mechanisms (unique to AGR fuel). The development of this model in a commercial FE package shows that the development of a potentially verified and future-proof fuel performance code can be created and used. The usability of a FE based fuel performance code would be an enhancement over past codes. Pre- and post-processors have lowered the entry barrier for the development of a fuel performance model to permit the ability to model complicated systems. Typical runtimes for a 5 year axisymmetric model takes less than one hour on a single core workstation. The current model has implemented: Non-linear fuel thermal behaviour, including a complex description of heat flow in the fuel. Coupled with a variety of

  6. Gas cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1972-06-01

    Although most of the development work on fast breeder reactors has been devoted to the use of liquid metal cooling, interest has been expressed for a number of years in alternative breeder concepts using other coolants. One of a number of concepts in which interest has been retained is the Gas-Cooled Fast Reactor (GCFR). As presently envisioned, it would operate on the uranium-plutonium mixed oxide fuel cycle, similar to that used in the Liquid Metal Fast Breeder Reactor (LMFBR), and would use helium gas as the coolant.

  7. Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, July 1, 1979-September 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-03-07

    The results of work performed from July 1, 1979 through September 30, 1979 on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment. The status of the data management system is presented. In addition, the progress in the screening test program is described.

  8. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, January 1, 1980-March 31, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-25

    Results are presented of work performed on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Included are the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described, including screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850, and 950/sup 0/C.

  9. Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, April 1, 1979-June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-01-25

    The results are presented of work performed on the Advanced Gas-Cooled Nuclear Reactor Materials Evaluation and Development Program. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment. The status of the data management system is presented. In addition, the progress in the screening test program is described.

  10. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, July 1--September 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-11-24

    Results of work performed from July 1, 1978 through September 30, 1978 on the Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program are presented. Candidate alloys were evaluated for Very High Temperature Reactor Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (Helium containing small amounts of various other gases), the high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. The activities associated with the characterization of the materials for the screening test program are reported, i.e., test specimen preparation, information from the materials characterization tests performed by General Electric, and the status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment. The status of the data management system is presented.

  11. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, September 23, 1976--December 31, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    This report presents the results of work performed from September 23, 1976 through December 31, 1976 on the Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. The objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Process Heat and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (impure Helium), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes progress to date on alloy selection for VHTR Nuclear Process Heat (NPH) applications and for DCHT applications. The present status on the simulated reactor helium loop design and on designs for the testing and analysis facilities and equipment is discussed.

  12. Neutron flux measurements in the side-core region of Hunterston B advanced gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Allen, D.A. [Serco, Rutherford House, Quedgeley, Gloucester, GL2 4NF (United Kingdom); Shaw, S.E. [British Energy, Barnett Way, Barnwood, Gloucester, GL4 3RS (United Kingdom); Huggon, A.P.; Steadman, R.J.; Thornton, D.A. [Serco, Rutherford House, Quedgeley, Gloucester, GL2 4NF (United Kingdom); Whiley, G.S. [British Energy, Barnett Way, Barnwood, Gloucester, GL4 3RS (United Kingdom)

    2011-07-01

    The core restraints of advanced gas-cooled reactors are important structural components that are required to maintain the geometric integrity of the cores. A review of neutron dosimetry for the sister stations Hunterston B and Hinkley Point B identified that earlier conservative assessments predicted high thermal neutron dose rates to key components of the restraint structure (the restraint rod welds), with the implication that some of them may be predicted to fail during a seismic event. A revised assessment was therefore undertaken [Thornton, D. A., Allen, D. A., Tyrrell, R. J., Meese, T. C., Huggon, A.P., Whiley, G. S., and Mossop, J. R., 'A Dosimetry Assessment for the Core Restraint of an Advanced Gas Cooled Reactor,' Proceedings of the 13. International Symposium on Reactor Dosimetry (ISRD-13, May 2008), World Scientific, River Edge, NJ, 2009, W. Voorbraak, L. Debarberis, and P. D'hondt, Eds., pp. 679-687] using a detailed 3D model and a Monte Carlo radiation transport program, MCBEND. This reassessment resulted in more realistic fast and thermal neutron dose recommendations, the latter in particular being much lower than had been thought previously. It is now desirable to improve confidence in these predictions by providing direct validation of the MCBEND model through the use of neutron flux measurements. This paper describes the programme of work being undertaken to deploy two neutron flux measurement 'stringers' within the side-core region of one of the Hunterston B reactors for the purpose of validating the MCBEND model. The design of the stringers and the determination of the preferred deployment locations have been informed by the use of detailed MCBEND flux calculations. These computational studies represent a rare opportunity to design a flux measurement beforehand, with the clear intention of minimising the anticipated uncertainties and obtaining measurements that are known to be representative of the neutron fields to which

  13. Advances in conceptual design of a gas-cooled accelerator driven system (ADS) transmutation devices to sustainable nuclear energy development

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Rosales; Fajardo, Garcia; Curbelo, Perez; Oliva, Munoz; Hernandez, Garcia, E-mail: jrosales@instec.cu [Higher Institute of Technologies and Applied Sciences, Habana City (Cuba); Castells, Escriva [Energetic Engeniering Institute, Politechnical University of Valencia, Valencia (Spain); Abanades [Department of Simulation of Termoenergetic Systems, Politechnical University of Madrid, Madrid (Spain)

    2011-07-01

    The possibilities of a nuclear energy development are considerably increasing with the world energetic demand increment. However, the management of nuclear waste from conventional nuclear power plants and its inventory minimization are the most important issues that should be addressed. Fast reactors and Accelerator Driven Systems (ADS) are the main options to reduce the long-lived radioactive waste inventory. Pebble Bed Very High Temperature advanced systems have great perspectives to assume the future nuclear energy development challenges. The conceptual design of a Transmutation Advanced Device for Sustainable Energy Applications (TADSEA) has been made in preliminary studies. The TADSEA is an ADS cooled by helium and moderated by graphite that uses as fuel small amounts of transuranic elements in the form of TRISO particles, confined in 3 cm radius graphite pebbles forming a pebble bed configuration. It would be used for nuclear waste transmutation and energy production. In this paper, the results of a method for calculating the number of whole pebbles fitting in a volume according to its size are showed. From these results, the packing fraction influence on the TADSEAs main work parameters is studied. In addition, a redesign of the previous configuration, according to the established conditions in the preliminary design, i.e. the exit thermal power, is made. On the other hand, the heterogeneity of the TRISO particles inside the pebbles can not be negligible. In this paper, a study of the power density distribution inside the pebbles by means of a detailed simulation of the TRISO fuel particles and using an homogeneous composition of the fuel is addressed. (author)

  14. Argon purge gas cooled by chill box

    Science.gov (United States)

    Spiro, L. W.

    1966-01-01

    Cooling argon purge gas by routing it through a shop-fabricated chill box reduces charring of tungsten inert gas torch head components. The argon gas is in a cooled state as it enters the torch and prevents buildup of char caused by the high concentrations of heat in the weld area during welding operations.

  15. A three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition in graphite components of advanced gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, D.O.; Robinson, A.T.; Allen, D.A.; Picton, D.J.; Thornton, D.A. [TCS, Serco, Rutherford House, Olympus Park, Quedgeley, Gloucester, Gloucestershire GL2 4NF (United Kingdom); Shaw, S.E. [EDF Energy, Barnet Way, Barnwood, Gloucester GL4 3RS (United Kingdom)

    2011-07-01

    This paper describes the development of a three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition (or nuclear heating) throughout the graphite cores of the UK's Advanced Gas-cooled Reactors. Advances in the development of the Monte Carlo radiation transport code MCBEND have enabled the efficient production of detailed fully three-dimensional models that utilise three-dimensional source distributions obtained from Core Follow data supplied by the reactor physics code PANTHER. The calculational approach can be simplified to reduce both the requisite number of intensive radiation transport calculations, as well as the quantity of data output. These simplifications have been qualified by comparison with explicit calculations and they have been shown not to introduce significant systematic uncertainties. Simple calculational approaches are described that allow users of the data to address the effects on neutron damage and nuclear energy deposition predictions of the feedback resulting from the mutual dependencies of graphite weight loss and nuclear energy deposition. (authors)

  16. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, January 1, 1978--March 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-06-26

    The activities associated with the procurement of the materials for the screening test program, information from vendor certification for the materials received, and preliminary information from the materials characterization tests performed by GE are reported. The construction status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment are discussed. The final recommended impurity levels for the screening phase helium are presented and the rational behind this gas chemistry is discussed. The status of the data management system is presented.

  17. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, October 1, 1979-December 31, 1979

    Energy Technology Data Exchange (ETDEWEB)

    1980-04-18

    This report presents the results of work performed from October 1, 1979 through December 31, 1979. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described. This includes: screening creep results, weight gain and post-exposure mechanical properties for materials thermally exposed at 750/sup 0/ and 850/sup 0/C (1382/sup 0/ and 1562/sup 0/F). In addition, the status of the data management system is described.

  18. Advanced gas cooled nuclear reactor materials evaluation and development program. Progress report, April 1--June 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    1978-08-31

    The objectives of the program are to evaluate candidate alloys for Very High Temperature Reactor Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the affect of simulated reactor primary coolant (Helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in the report includes the activities associated with the procurement of the materials for the screening test program, information from vendor certification for the materials receiver, and preliminary information from the materials characterization tests performed by General Electric. The construction status of the simulated reactor helium supply system, testing equipment, and gas chemistry analysis instrumentation and equipment are discussed. The status of the data management system is also reviewed.

  19. Compatibility of gas turbine materials with steam cooling

    Energy Technology Data Exchange (ETDEWEB)

    Desai, V.; Tamboli, D.; Patel, Y. [Univ. of Central Florida, Orlando, FL (United States)

    1995-10-01

    Gas turbines had been traditionally used for peak load plants and remote locations as they offer advantage of low installation costs and quick start up time. Their use as a base load generator had not been feasible owing to their poor efficiency. However, with the advent of gas turbines based combined cycle plants (CCPs), continued advances in efficiency are being made. Coupled with ultra low NO{sub x} emissions, coal compatibility and higher unit output, gas turbines are now competing with conventional power plants for base load power generation. Currently, the turbines are designed with TIT of 2300{degrees}F and metal temperatures are maintained around 1700{degrees}F by using air cooling. New higher efficiency ATS turbines will have TIT as high as 2700{degrees}F. To withstand this high temperature improved materials, coatings, and advances in cooling system and design are warranted. Development of advanced materials with better capabilities specifically for land base applications are time consuming and may not be available by ATS time frame or may prove costly for the first generation ATS gas turbines. Therefore improvement in the cooling system of hot components, which can take place in a relatively shorter time frame, is important. One way to improve cooling efficiency is to use better cooling agent. Steam as an alternate cooling agent offers attractive advantages because of its higher specific heat (almost twice that of air) and lower viscosity.

  20. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, April 1, 1980-June 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-11-14

    Objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described; this includes: screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850 and 950/sup 0/C. The initiation of air creep-rupture testing in the intensive screening test program is discussed. In addition, the status of the data management system is described.

  1. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program. Progress report, July 1, 1980-September 30, 1980

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-12

    Objectives of this program are to evaluate candidate alloys for Very High Temperature Reactor (VHTR) Nuclear Process Heat (NPH) and Direct Cycle Helium Turbine (DCHT) applications, in terms of the effect of simulated reactor primary coolant (helium containing small amounts of various other gases), high temperatures, and long time exposures, on the mechanical properties and structural and surface stability of selected candidate alloys. A second objective is to select and recommend materials for future test facilities and more extensive qualification programs. Work covered in this report includes the activities associated with the status of the simulated reactor helium supply system, testing equipment and gas chemistry analysis instrumentation and equipment. The progress in the screening test program is described: screening creep results and metallographic analysis for materials thermally exposed or tested at 750, 850, 950 and 1050/sup 0/C. Initiation of controlled purity helium creep-rupture testing in the intensive screening test program is discussed. In addition, the results of 1000-hour exposures at 750 and 850/sup 0/C on several experimental alloys are discussed.

  2. Advances in Solar Heating and Cooling Systems

    Science.gov (United States)

    Ward, Dan S.

    1976-01-01

    Reports on technological advancements in the fields of solar collectors, thermal storage systems, and solar heating and cooling systems. Diagrams aid in the understanding of the thermodynamics of the systems. (CP)

  3. Cooling arrangement for a gas turbine component

    Science.gov (United States)

    Lee, Ching-Pang; Heneveld, Benjamin E

    2015-02-10

    A cooling arrangement (82) for a gas turbine engine component, the cooling arrangement (82) having a plurality of rows (92, 94, 96) of airfoils (98), wherein adjacent airfoils (98) within a row (92, 94, 96) define segments (110, 130, 140) of cooling channels (90), and wherein outlets (114, 134) of the segments (110, 130) in one row (92, 94) align aerodynamically with inlets (132, 142) of segments (130, 140) in an adjacent row (94, 96) to define continuous cooling channels (90) with non continuous walls (116, 120), each cooling channel (90) comprising a serpentine shape.

  4. Warm Absorbing Gas in Cooling Flows

    OpenAIRE

    Buote, David A.

    2000-01-01

    We summarize the discovery of oxygen absorption and warm (10^5-10^6 K) gas in cooling flows. Special attention is given to new results for M87 for which we find the strongest evidence to date for ionized oxygen absorption in these systems. We briefly discuss implications for observations of cooling flows with Chandra and XMM.

  5. Dimethylamine as a replacement for ammonia dosing in the secondary circuit of an advanced gas-cooled reactor (AGR) power station

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Chris; Mitchell, Malcolm S. [EDF Energy, Hartlepool Power Station, Hartlepool (United Kingdom); Bull, Andrew E.A.; Quirk, Graham P.; Rudge, Andy [EDF Energy Nuclear Generation, Barnwood, Gloucester (United Kingdom). Central Technical Organisation; Woolsey, Ian S.

    2012-06-15

    Increasing flow resistance observed over recent years within the helical once-through boilers in the four advanced gas-cooled reactors at Hartlepool and Heysham 1 Power Stations have reduced boiler performance, resulting in reductions in feedwater flow, steam temperatures, and power output and in the need to carry out periodic chemical cleaning. The root cause is believed to be the development of magnetite deposits with high flow impedance in the 9Cr1Mo evaporator section of the boiler tubing. To prevent continued increases in boiler flow resistance, dimethylamine is being trialled, in one of the four affected units, as a replacement to the conventional ammonia dosing. Dimethylamine increases the pH at temperature around the secondary circuit and, based on full scale boiler rig simulations, is expected to reduce iron transport and prevent flow resistance increases within the evaporator section of the boiler. The dimethylamine plant trial commenced in January 2011 and is ongoing. The feedwater concentration of dimethylamine has been increased progressively towards a final target value of 900 {mu}g . kg{sup -1} and its effect on iron transport and boiler pressure loss is being closely monitored. The high steam temperature (> 500 C) of the secondary circuit leads to some decomposition of dimethylamine, which is being carefully monitored at various locations around the circuit. The decomposition products identified with dimethylamine dosing include ammonia, methylamine, formic acid, carbon dioxide and, as yet, unidentified neutral organic species. The effect of dimethylamine dosing on iron transport and boiler pressure drops and its decomposition behaviour around the secondary circuit during the plant trial will be presented in this paper. (orig.)

  6. Hot gas path component cooling system

    Science.gov (United States)

    Lacy, Benjamin Paul; Bunker, Ronald Scott; Itzel, Gary Michael

    2014-02-18

    A cooling system for a hot gas path component is disclosed. The cooling system may include a component layer and a cover layer. The component layer may include a first inner surface and a second outer surface. The second outer surface may define a plurality of channels. The component layer may further define a plurality of passages extending generally between the first inner surface and the second outer surface. Each of the plurality of channels may be fluidly connected to at least one of the plurality of passages. The cover layer may be situated adjacent the second outer surface of the component layer. The plurality of passages may be configured to flow a cooling medium to the plurality of channels and provide impingement cooling to the cover layer. The plurality of channels may be configured to flow cooling medium therethrough, cooling the cover layer.

  7. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    E.S. Connolly; G.D. Forsythe

    1998-12-22

    Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

  8. Ultrasonic gas accumulation detection and evaluation in nuclear cooling pipes

    Science.gov (United States)

    Yu, Lingyu; Lin, Bin; Shin, Yong-June; Wang, Jingjiang; Tian, Zhenhua

    2012-04-01

    This paper presents a novel ultrasonic guided wave based inspection methodology for detecting and evaluating gas accumulation in nuclear cooling pipe system. The sensing is in-situ by means of low-profile permanently installed piezoelectric wafer sensors to excite interrogating guided waves and to receive the propagating waves in the pipe structure. Detection and evaluation is established through advanced cross time-frequency analysis to extract the phase change in the sensed signal when the gas is accumulating. A correlation between the phase change and the gas amount has been established to provide regulatory prediction capability based on measured sensory data.

  9. A buffer gas cooled beam of barium monohydride

    Science.gov (United States)

    Iwata, Geoffrey; Tarallo, Marco; Zelevinsky, Tanya

    2016-05-01

    Significant advances in direct laser cooling of diatomic molecules have opened up a wide array of molecular species to precision studies spanning many-body physics, quantum collisions and ultracold dissociation. We present a cryogenic beam source of barium monohydride (BaH), and study laser ablation of solid precursor targets as well as helium buffer gas cooling dynamics. Additionally, we cover progress towards a molecular magneto-optical trap, with spectroscopic studies of relevant cooling transitions in the B2 Σ molecules, including resolution of hyperfine structure and precision measurements of the vibrational Frank-Condon factors. Finally, we examine the feasibility of photo dissociation of trapped BaH molecules to yield optically accessible samples of ultracold hydrogen.

  10. Gas turbine vane cooling air insert

    Energy Technology Data Exchange (ETDEWEB)

    North, W.E.; Hultgren, K.G.; Dishman, C.D.; Van Heusden, G.S.

    1992-09-08

    This patent describes a gas turbine. It comprises turbine vanes, each of the vanes supplied with cooling air and having: an airfoil portion forming a first cavity having an insert disposed therein for directing the flow of the cooling air, the insert having first and second insert ends; a shroud portion from which the airfoil portion extends, the insert attached to the shroud portion at the first insert end; an insert extension extending through a portion of the insert and extending beyond the first insert end, the insert extension and the insert forming an annular gap therebetween separating the insert from the insert extension; a plate covering at least a portion of the shroud, the plate having a first hole formed therein through which the insert extension extends; and at least a first seal extending between the insert extension and the insert, and sealing the annular gap therebetween. This patent also describes a method of making a gas turbine. It comprises welding a first tubular insert adjacent its first end to a vane outer shroud; partially inserting a second tubular insert into the first tubular member and attaching the second tubular insert thereto; placing a plate having a hole formed therein on the outer shroud so that the hole surrounds the second tubular insert; and attaching the second tubular insert to the plate by placing a first seal between the first and second tubular inserts and attaching the first seal to each of the first and second tubular inserts, and placing a second seal between the second tubular insert and the plate and welding the second seal to the second tubular insert and the plate.

  11. Advanced IGCC/Hydrogen Gas Turbine Development

    Energy Technology Data Exchange (ETDEWEB)

    York, William [General Electric Company, Schenectady, NY (United States); Hughes, Michael [General Electric Company, Schenectady, NY (United States); Berry, Jonathan [General Electric Company, Schenectady, NY (United States); Russell, Tamara [General Electric Company, Schenectady, NY (United States); Lau, Y. C. [General Electric Company, Schenectady, NY (United States); Liu, Shan [General Electric Company, Schenectady, NY (United States); Arnett, Michael [General Electric Company, Schenectady, NY (United States); Peck, Arthur [General Electric Company, Schenectady, NY (United States); Tralshawala, Nilesh [General Electric Company, Schenectady, NY (United States); Weber, Joseph [General Electric Company, Schenectady, NY (United States); Benjamin, Marc [General Electric Company, Schenectady, NY (United States); Iduate, Michelle [General Electric Company, Schenectady, NY (United States); Kittleson, Jacob [General Electric Company, Schenectady, NY (United States); Garcia-Crespo, Andres [General Electric Company, Schenectady, NY (United States); Delvaux, John [General Electric Company, Schenectady, NY (United States); Casanova, Fernando [General Electric Company, Schenectady, NY (United States); Lacy, Ben [General Electric Company, Schenectady, NY (United States); Brzek, Brian [General Electric Company, Schenectady, NY (United States); Wolfe, Chris [General Electric Company, Schenectady, NY (United States); Palafox, Pepe [General Electric Company, Schenectady, NY (United States); Ding, Ben [General Electric Company, Schenectady, NY (United States); Badding, Bruce [General Electric Company, Schenectady, NY (United States); McDuffie, Dwayne [General Electric Company, Schenectady, NY (United States); Zemsky, Christine [General Electric Company, Schenectady, NY (United States)

    2015-07-30

    The objective of this program was to develop the technologies required for a fuel flexible (coal derived hydrogen or syngas) gas turbine for IGCC that met DOE turbine performance goals. The overall DOE Advanced Power System goal was to conduct the research and development (R&D) necessary to produce coal-based IGCC power systems with high efficiency, near-zero emissions, and competitive capital cost. To meet this goal, the DOE Fossil Energy Turbine Program had as an interim objective of 2 to 3 percentage points improvement in combined cycle (CC) efficiency. The final goal is 3 to 5 percentage points improvement in CC efficiency above the state of the art for CC turbines in IGCC applications at the time the program started. The efficiency goals were for NOx emissions of less than 2 ppm NOx (@15 % O2). As a result of the technologies developed under this program, the DOE goals were exceeded with a projected 8 point efficiency improvement. In addition, a new combustion technology was conceived of and developed to overcome the challenges of burning hydrogen and achieving the DOE’s NOx goal. This report also covers the developments under the ARRA-funded portion of the program that include gas turbine technology advancements for improvement in the efficiency, emissions, and cost performance of gas turbines for industrial applications with carbon capture and sequestration. Example applications could be cement plants, chemical plants, refineries, steel and aluminum plants, manufacturing facilities, etc. The DOE’s goal for more than 5 percentage point improvement in efficiency was met with cycle analyses performed for representative IGCC Steel Mill and IGCC Refinery applications. Technologies were developed in this program under the following areas: combustion, larger latter stage buckets, CMC and EBC, advanced materials and coatings, advanced configurations to reduce cooling, sealing and rotor purge flows, turbine aerodynamics, advanced sensors, advancements in first

  12. Recent advances in laser cooling of solids

    Science.gov (United States)

    Nemova, Galina; Kashyap, Raman

    2013-10-01

    The recent achievements devoted to cooling of solids with a laser are presented in this paper. We discuss the latest results of traditional laser cooling of solids based on rare earth ions and new techniques based on colloidal lead-salt quantum dots doped in a glass host, laser cooling in Tm3+-doped oxy-fluoride glass ceramic. Relatively short (microsecond) lifetime of the excited level of the PbSe QDs compared to the millisecond lifetime of the excited level of RE ions allows an acceleration of the cooling process and provides an opportunity to use new materials with higher phonon energy as hosts, which are normally considered unsuitable for cooling with RE ions. Another new approach to the laser cooling problem based on super-radiance has been considered in this paper. The advantages of optical refrigeration with rare earth doped semiconductors, in which not only optically active electrons of the 4f shell but the valence and conduction bands of the host material are involved in cooling cycle is discussed. It is shown that involving the valence and conduction bands of the host in the cooling cycle allows the pump wavelength to be shorter than mean fluorescence wavelength. Raman laser cooling of solids as well as observation of spontaneous Brillouin cooling have been presented.

  13. Gas turbine heat transfer and cooling technology

    CERN Document Server

    Han, Je-Chin; Ekkad, Srinath

    2012-01-01

    FundamentalsNeed for Turbine Blade CoolingTurbine-Cooling TechnologyTurbine Heat Transfer and Cooling IssuesStructure of the BookReview Articles and Book Chapters on Turbine Cooling and Heat TransferNew Information from 2000 to 2010ReferencesTurbine Heat TransferIntroductionTurbine-Stage Heat TransferCascade Vane Heat-Transfer ExperimentsCascade Blade Heat TransferAirfoil Endwall Heat TransferTurbine Rotor Blade Tip Heat TransferLeading-Edge Region Heat TransferFlat-Surface Heat TransferNew Information from 2000 to 20102.10 ClosureReferencesTurbine Film CoolingIntroductionFilm Cooling on Rotat

  14. Application of Hastelloy X in Gas-Cooled Reactor Systems

    DEFF Research Database (Denmark)

    Brinkman, C. R.; Rittenhouse, P. L.; Corwin, W.R.

    1976-01-01

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data...

  15. Update on DOE Advanced IGCC/H2 Gas Turbine

    Science.gov (United States)

    Chupp, Ray

    2009-01-01

    Cooling Flow Reduction: a) Focus on improving turbine hot gas path part cooling efficiency. b) Applicable to current metallic turbine components and synergistic with advanced materials. c) Address challenges of IGCC/hydrogen fuel environment (for example, possible cooling hole plugging). Leakage Flow Reduction: a) Focus on decreasing turbine parasitic leakages, i.e. between static-to-static, static-to-rotating turbine parts. b) Develop improved seal designs in a variety of important areas. Purge Flow Reduction: a) Focus on decreasing required flows to keep rotor disk cavities within temperature limits. b) Develop improved sealing at the cavity rims and modified flow geometries to minimize hot gas ingestion and aerodynamic impact.

  16. Evaluating the income and employment impacts of gas cooling technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, P.J. [Oak Ridge National Lab., TN (United States); Laitner, S.

    1995-03-01

    The purpose of this study is to estimate the potential employment and income benefits of the emerging market for gas cooling products. The emphasis here is on exports because that is the major opportunity for the U.S. heating, ventilating, and air-conditioning (HVAC) industry. But domestic markets are also important and considered here because without a significant domestic market, it is unlikely that the plant investments, jobs, and income associated with gas cooling exports would be retained within the United States. The prospects for significant gas cooling exports appear promising for a variety of reasons. There is an expanding need for cooling in the developing world, natural gas is widely available, electric infrastructures are over-stressed in many areas, and the cost of building new gas infrastructure is modest compared to the cost of new electric infrastructure. Global gas cooling competition is currently limited, with Japanese and U.S. companies, and their foreign business partners, the only product sources. U.S. manufacturers of HVAC products are well positioned to compete globally, and are already one of the faster growing goods-exporting sectors of the U.S. economy. Net HVAC exports grew by over 800 percent from 1987 to 1992 and currently exceed $2.6 billion annually (ARI 1994). Net gas cooling job and income creation are estimated using an economic input-output model to compare a reference case to a gas cooling scenario. The reference case reflects current policies, practices, and trends with respect to conventional electric cooling technologies. The gas cooling scenario examines the impact of accelerated use of natural gas cooling technologies here and abroad.

  17. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  18. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-02-01

    The activities of the Advanced Gas Turbine Systems Research (AGTSR) program for this reporting period are described in this quarterly report. The report is divided into discussions of Membership, Administration, Technology Transfer (Workshop/Education), Research and Miscellaneous Related Activity. Items worthy of note are presented in extended bullet format following the appropriate heading.

  19. Radial molecular abundances and gas cooling in starless cores

    CERN Document Server

    Sipilä, O

    2012-01-01

    Aims: We aim to simulate radial profiles of molecular abundances and the gas temperature in cold and heavily shielded starless cores by combining chemical and radiative transfer models. Methods: A determination of the dust temperature in a modified Bonnor-Ebert sphere is used to calculate initial radial molecular abundance profiles. The abundances of selected cooling molecules corresponding to two different core ages are then extracted to determine the gas temperature at two time steps. The calculation is repeated in an iterative process yielding molecular abundances consistent with the gas temperature. Line emission profiles for selected substances are calculated using simulated abundance profiles. Results: The gas temperature is a function of time; the gas heats up as the core gets older because the cooling molecules are depleted onto grain surfaces. The contributions of the various cooling molecules to the total cooling power change with time. Radial chemical abundance profiles are non-trivial: different s...

  20. Advanced Turbine Blade Cooling Techniques Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Gas turbine engine technology is constantly challenged to operate at higher combustor outlet temperatures. In a modern gas turbine engine, these temperatures can...

  1. High temperature gas-cooled reactor: gas turbine application study

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project.

  2. Production of Depleted UO2Kernels for the Advanced Gas-Cooled Reactor Program for Use in TRISO Coating Development

    Energy Technology Data Exchange (ETDEWEB)

    Collins, J.L.

    2004-12-02

    The main objective of the Depleted UO{sub 2} Kernels Production Task at Oak Ridge National Laboratory (ORNL) was to conduct two small-scale production campaigns to produce 2 kg of UO{sub 2} kernels with diameters of 500 {+-} 20 {micro}m and 3.5 kg of UO{sub 2} kernels with diameters of 350 {+-} 10 {micro}m for the U.S. Department of Energy Advanced Fuel Cycle Initiative Program. The final acceptance requirements for the UO{sub 2} kernels are provided in the first section of this report. The kernels were prepared for use by the ORNL Metals and Ceramics Division in a development study to perfect the triisotropic (TRISO) coating process. It was important that the kernels be strong and near theoretical density, with excellent sphericity, minimal surface roughness, and no cracking. This report gives a detailed description of the production efforts and results as well as an in-depth description of the internal gelation process and its chemistry. It describes the laboratory-scale gel-forming apparatus, optimum broth formulation and operating conditions, preparation of the acid-deficient uranyl nitrate stock solution, the system used to provide uniform broth droplet formation and control, and the process of calcining and sintering UO{sub 3} {center_dot} 2H{sub 2}O microspheres to form dense UO{sub 2} kernels. The report also describes improvements and best past practices for uranium kernel formation via the internal gelation process, which utilizes hexamethylenetetramine and urea. Improvements were made in broth formulation and broth droplet formation and control that made it possible in many of the runs in the campaign to produce the desired 350 {+-} 10-{micro}m-diameter kernels, and to obtain very high yields.

  3. Advanced materials for radiation-cooled rockets

    Science.gov (United States)

    Reed, Brian; Biaglow, James; Schneider, Steven

    1993-01-01

    The most common material system currently used for low thrust, radiation-cooled rockets is a niobium alloy (C-103) with a fused silica coating (R-512A or R-512E) for oxidation protection. However, significant amounts of fuel film cooling are usually required to keep the material below its maximum operating temperature of 1370 C, degrading engine performance. Also the R-512 coating is subject to cracking and eventual spalling after repeated thermal cycling. A new class of high-temperature, oxidation-resistant materials are being developed for radiation-cooled rockets, with the thermal margin to reduce or eliminate fuel film cooling, while still exceeding the life of silicide-coated niobium. Rhenium coated with iridium is the most developed of these high-temperature materials. Efforts are on-going to develop 22 N, 62 N, and 440 N engines composed of these materials for apogee insertion, attitude control, and other functions. There is also a complimentary NASA and industry effort to determine the life limiting mechanisms and characterize the thermomechanical properties of these materials. Other material systems are also being studied which may offer more thermal margin and/or oxidation resistance, such as hafnium carbide/tantalum carbide matrix composites and ceramic oxide-coated iridium/rhenium chambers.

  4. How to get cool in the heat: comparing analytic models of halo gas cooling with EAGLE

    CERN Document Server

    Stevens, Adam R H; Contreras, Sergio; Croton, Darren J; Padilla, Nelson D; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2016-01-01

    We use the hydrodynamic, cosmological EAGLE simulations to investigate how hot gas in haloes condenses to form and grow galaxies. We select haloes from the simulations that are actively cooling and study the temperature, distribution, and metallicity of their hot, cold, and transitioning `cooling' gas, placing these in context of semi-analytic models. Our selection criteria lead us to focus on Milky Way-like haloes. We find the hot-gas density profiles of the haloes form a progressively stronger core over time, the nature of which can be captured by a beta profile that has a simple dependence on redshift. In contrast, the hot gas that actually cools is broadly consistent with a singular isothermal sphere. We find that cooling gas carries a few times the specific angular momentum of the halo and is offset in spin direction from the rest of the hot gas. The gas loses ~60% of its specific angular momentum during the cooling process, generally remaining greater than that of the halo, and is better aligned with th...

  5. The cooling of shock-compressed primordial gas

    CERN Document Server

    Johnson, J L; Johnson, Jarrett L.; Bromm, Volker

    2006-01-01

    We find that at redshifts z > 10, HD line cooling allows strongly-shocked primordial gas to cool to the temperature of the cosmic microwave background (CMB). This temperature is the minimum value attainable via radiative cooling. Provided that the abundance of HD, normalized to the total number density, exceeds a critical level of ~ 10^{-8}, the CMB temperature floor is reached in a time which is short compared to the Hubble time. We estimate the characteristic masses of stars formed out of shocked primordial gas in the wake of the first supernovae, and resulting from the mergers of dark matter haloes during hierarchical structure formation to be ~ 10 M_{solar}. In addition, we show that cooling by HD enables the primordial gas in relic H II regions to cool to temperatures considerably lower than those reached via H_2 cooling alone. We confirm that HD cooling is unimportant in cases where the primordial gas does not go through an ionized phase, as in the formation process of the very first stars in z ~ 20 min...

  6. Advanced gas turbine systems program

    Energy Technology Data Exchange (ETDEWEB)

    Zeh, C.M.

    1995-06-01

    The U.S. Department of Energy (DOE) is sponsoring a program to develop fuel-efficient gas turbine-based power systems with low emissions. DOE`s Office of Fossil Energy (DOE/FE) and Office of Energy Efficiency and Renewable Energy (DOE/EE) have initiated an 8-year program to develop high-efficiency, natural gas-fired advanced gas turbine power systems. The Advanced Turbine Systems (ATS) Program will support full-scale prototype demonstration of both industrial- and utility-scale systems that will provide commercial marketplace entries by the year 2000. When the program targets are met, power system emissions will be lower than from the best technology in use today. Efficiency of the utility-scale units will be greater than 60 percent on a lower heating value basis, and emissions of carbon dioxide will be reduced inversely with this increase. Industrial systems will also see an improvement of at least 15 percent in efficiency. Nitrogen oxides will be reduced by at least 10 percent, and carbon monoxide and hydrocarbon emissions will each be kept below 20 parts per million, for both utility and industrial systems.

  7. Laser cooling in solids: advances and prospects

    Science.gov (United States)

    Seletskiy, Denis V.; Epstein, Richard; Sheik-Bahae, Mansoor

    2016-09-01

    This review discusses the progress and ongoing efforts in optical refrigeration. Optical refrigeration is a process in which phonons are removed from a solid by anti-Stokes fluorescence. The review first summarizes the history of optical refrigeration, noting the success in cooling rare-earth-doped solids to cryogenic temperatures. It then examines in detail a four-level model of rare-earth-based optical refrigeration. This model elucidates the essential roles that the various material parameters, such as the spacing of the energy levels and the radiative quantum efficiency, play in the process of optical refrigeration. The review then describes the experimental techniques for cryogenic optical refrigeration of rare-earth-doped solids employing non-resonant and resonant optical cavities. It then examines the work on laser cooling of semiconductors, emphasizing the differences between optical refrigeration of semiconductors and rare-earth-doped solids and the new challenges and advantages of semiconductors. It then describes the significant experimental results including the observed optical refrigeration of CdS nanostructures. The review concludes by discussing the engineering challenges to the development of practical optical refrigerators, and the potential advantages and uses of these refrigerators.

  8. Testing aspects of advanced coherent electron cooling technique

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, V.; Jing, Y.; Pinayev, I.; Wang, G.; Samulyak, R.; Ratner, D.

    2015-05-03

    An advanced version of the Coherent-electron Cooling (CeC) based on the micro-bunching instability was proposed. This approach promises significant increase in the bandwidth of the CeC system and, therefore, significant shortening of cooling time in high-energy hadron colliders. In this paper we present our plans of simulating and testing the key aspects of this proposed technique using the set-up of the coherent-electron-cooling proof-of-principle experiment at BNL.

  9. Challenges to Introduce Advanced Cooling Technology by the Utilization of Plural Cooling Velocity

    Institute of Scientific and Technical Information of China (English)

    Kiyoshi Funatani

    2004-01-01

    The control of cooling power is very important to introduce desired properties. Usually, higher the cooling rate higher the quench hardness and distortion and the optimization of cooling power is the base for good heat treatment. The change of cooling speed during quenching is one of the effective methods to balance hardness and distortion. Different form the general knowledge of the demerit of vapor blanket stage, oil with long vapor blanket stage is also one of effective methods to reduce distortion. The reduction of distortion with enough quench hardness seems to be possible by optimization of cooling condition by the help of computer simulation. The exhibition of higher core hardness than surface in through hardening steels experienced in the "Inverse quench hardening" was introduced by Prof. Tamura and Shimizu. This mechanism is well explained by Arimoto et al, by analysis of computer simulation. In this paper, plural steps cooling methods are compared, in relation with cooling curve and heat transfer coefficient that is necessary to simulate quench results and the possibility of advanced cooling technology is discussed.

  10. Cooling of gas turbines IX : cooling effects from use of ceramic coatings on water-cooled turbine blades

    Science.gov (United States)

    Brown, W Byron; Livingood, John N B

    1948-01-01

    The hottest part of a turbine blade is likely to be the trailing portion. When the blades are cooled and when water is used as the coolant, the cooling passages are placed as close as possible to the trailing edge in order to cool this portion. In some cases, however, the trailing portion of the blade is so narrow, for aerodynamic reasons, that water passages cannot be located very near the trailing edge. Because ceramic coatings offer the possibility of protection for the trailing part of such narrow blades, a theoretical study has been made of the cooling effect of a ceramic coating on: (1) the blade-metal temperature when the gas temperature is unchanged, and (2) the gas temperature when the metal temperature is unchanged. Comparison is also made between the changes in the blade or gas temperatures produced by ceramic coatings and the changes produced by moving the cooling passages nearer the trailing edge. This comparison was made to provide a standard for evaluating the gains obtainable with ceramic coatings as compared to those obtainable by constructing the turbine blade in such a manner that water passages could be located very near the trailing edge.

  11. Applications for Solid Propellant Cool Gas Generator Technology

    Science.gov (United States)

    van der List, M.; van Vliet, L. D.; Sanders, H. M.; Put, P. A. G.; Elst, J. W. E. C.

    2004-10-01

    In 2002 and 2003, Bradford Engineering B.V. conducted, in corporation with the Dutch research institute TNO Prins Maurits Laboratory (PML) a SME study for ESA-ESTEC for the identification of spaceflight applications and on-ground demonstration of Solid Propellant Cool Gas Generator (SPCGG) technology. This innovative technology has been developed by TNO-PML while Bradford Engineering also brought in its experience in spaceflight hardware development and manufacturing. The Solid Propellant Cool Gas Generator (SPCGG) technology allows for pure gas generation at ambient temperatures, as opposed to conventional solid propellant gas generators. This makes the SPCGG technology interesting for a wide range of terrestrial spaceflight applications. During the first part of the study, a variety of potential applications have been identified and three applications were selected for a more detailed quantitative study. In the third phase a ground demonstration was performed successfully for a cold gas propulsion system application. During the actual demonstration test, 10 cool gas generators were mounted and all operated successfully in sequence, demonstrating good repeatability of the produced amount of gas and pressure.

  12. Contribution of HD molecules in cooling of the primordial gas

    CERN Document Server

    Vasiliev, E O; Shchekinov, Yu. A.

    2005-01-01

    We study the effects of HD molecules on thermochemical evolution of the primordial gas behind shock waves, possibly arised in the process of galaxy formation. We find the critical shock velocity when deuterium transforms efficiently into HD molecules which then dominate gas cooling. Above this velocity the shocked gas is able to cool down to the temperature of the cosmic microwave background. Under these conditions the corresponding Jeans mass depends only on redshift and initial density of baryons $M_J \\propto \\delta_c^{-0.5} (1+z)^{0.5}$. At $z\\simgt 45$ HD molecules heat shocked gas, and at larger redshift their contribution to thermal evolution becomes negligible.

  13. Fuel development for gas-cooled fast reactors

    Science.gov (United States)

    Meyer, M. K.; Fielding, R.; Gan, J.

    2007-09-01

    The Generation IV Gas-cooled Fast Reactor (GFR) concept is proposed to combine the advantages of high-temperature gas-cooled reactors (such as efficient direct conversion with a gas turbine and the potential for application of high-temperature process heat), with the sustainability advantages that are possible with a fast-spectrum reactor. The latter include the ability to fission all transuranics and the potential for breeding. The GFR is part of a consistent set of gas-cooled reactors that includes a medium-term Pebble Bed Modular Reactor (PBMR)-like concept, or concepts based on the Gas Turbine Modular Helium Reactor (GT-MHR), and specialized concepts such as the Very High-Temperature Reactor (VHTR), as well as actinide burning concepts [A Technology Roadmap for Generation IV Nuclear Energy Systems, US DOE Nuclear Energy Research Advisory Committee and the Generation IV International Forum, December 2002]. To achieve the necessary high power density and the ability to retain fission gas at high temperature, the primary fuel concept proposed for testing in the United States is dispersion coated fuel particles in a ceramic matrix. Alternative fuel concepts considered in the US and internationally include coated particle beds, ceramic clad fuel pins, and novel ceramic 'honeycomb' structures. Both mixed carbide and mixed nitride-based solid solutions are considered as fuel phases.

  14. International working group on gas-cooled reactors. Summary report

    Energy Technology Data Exchange (ETDEWEB)

    1981-01-15

    The purpose of the meeting was to provide a forum for exchange of information on safety and licensing aspects for gas-cooled reactors in order to provide comprehensive review of the present status and of directions for future applications and development. Contributions were made concerning the operating experience of the Fort St. Vrain (FSV) HTGR Power Plant in the United States of America, the experimental power station Arbeitsgemeinschaft Versuchsreaktor (AVR) in the Federal Republic of Germany, and the CO/sub 2/-cooled reactors in the United Kingdom such as Hunterson B and Hinkley Point B. The experience gained at each of these reactors has proved the high safety potential of Gas-cooled Reactor Power Plants.

  15. Control rod drive for high temperature gas cooled reactor

    Institute of Scientific and Technical Information of China (English)

    DengJun-Xian; XuJi-Ming; 等

    1998-01-01

    This control rod drive is developed for HTR-10 high temperature gas cooled test reactor.The stepmotor is prefered to improve positioning of the control rod and the scram behavior.The preliminary test in 1600170 ambient temperature shows that the selected stepmotor and transmission system can meet the main operation function requirements of HTR-10.

  16. High Temperature Gas-Cooled Test Reactor Options Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bayless, Paul David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-08-01

    Preliminary scoping calculations are being performed for a 100 MWt gas-cooled test reactor. The initial design uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to identify some reactor design features to investigate further. Current status of the effort is described.

  17. Gas Cooled, Natural Uranium, D20 Moderated Power Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Dahlberg, R.C.; Beasley, E.G.; DeBoer, T.K.; Evans, T.C.; Molino, D.F.; Rothwell, W.S.; Slivka, W.R.

    1956-08-01

    The attractiveness of a helium cooled, heavy water moderated, natural uranium central station power plant has been investigated. A fuel element has been devised which allows the D20 to be kept at a low pressure while the exit gas temperature is high. A preliminary cost analysis indicates that, using currently available materials, competitive nuclear power in foreign countries is possible.

  18. AGN-stimulated Cooling of Hot Gas in Elliptical Galaxies

    CERN Document Server

    Valentini, Milena

    2015-01-01

    We study the impact of relatively weak AGN feedback on the interstellar medium of intermediate and massive elliptical galaxies. We find that the AGN activity, while globally heating the ISM, naturally stimulates some degree of hot gas cooling on scales of several kpc. This process generates the persistent presence of a cold ISM phase, with mass ranging between 10$^4$ and $\\gtrsim$ 5 $\\times$ 10$^7$ M$_\\odot$, where the latter value is appropriate for group centered, massive galaxies. Widespread cooling occurs where the ratio of cooling to free-fall time before the activation of the AGN feedback satisfies $t_{cool}/t_{ff} \\lesssim 70$, that is we find a less restrictive threshold than commonly quoted in the literature. This process helps explaining the body of observations of cold gas (both ionized and neutral/molecular) in Ellipticals and, perhaps, the residual star formation detected in many early-type galaxies. The amount and distribution of the off-center cold gas vary irregularly with time. The cold ISM v...

  19. Gas-Cooled Fast Reactor (GFR) FY05 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    K. D. Weaver; T. Marshall; T. Totemeier; J. Gan; E.E. Feldman; E.A Hoffman; R.F. Kulak; I.U. Therios; C. P. Tzanos; T.Y.C. Wei; L-Y. Cheng; H. Ludewig; J. Jo; R. Nanstad; W. Corwin; V. G. Krishnardula; W. F. Gale; J. W. Fergus; P. Sabharwall; T. Allen

    2005-09-01

    The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radio toxicity of both its own fuel and other spent nuclear fuel, and for extending/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize. In addition, energy conversion at high thermal efficiency is possible with the current designs being considered, thus increasing the economic benefit of the GFR. However, research and development challenges include the ability to use passive decay heat removal systems during accident conditions, survivability of fuels and in-core materials under extreme temperatures and radiation, and economical and efficient fuel cycle processes. Nevertheless, the GFR was chosen as one of only six Generation IV systems to be pursued based on its ability to meet the Generation IV goals in sustainability, economics, safety and reliability, proliferation resistance and physical protection. Current research and development on the Gas-Cooled Fast Reactor (GFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFCI) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GFR: a helium-cooled, direct power conversion system that will operate with on outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in

  20. Ambient air cooling arrangement having a pre-swirler for gas turbine engine blade cooling

    Science.gov (United States)

    Lee, Ching-Pang; Tham, Kok-Mun; Schroeder, Eric; Meeroff, Jamie; Miller, Jr., Samuel R; Marra, John J

    2015-01-06

    A gas turbine engine including: an ambient-air cooling circuit (10) having a cooling channel (26) disposed in a turbine blade (22) and in fluid communication with a source (12) of ambient air: and an pre-swirler (18), the pre-swirler having: an inner shroud (38); an outer shroud (56); and a plurality of guide vanes (42), each spanning from the inner shroud to the outer shroud. Circumferentially adjacent guide vanes (46, 48) define respective nozzles (44) there between. Forces created by a rotation of the turbine blade motivate ambient air through the cooling circuit. The pre-swirler is configured to impart swirl to ambient air drawn through the nozzles and to direct the swirled ambient air toward a base of the turbine blade. The end walls (50, 54) of the pre-swirler may be contoured.

  1. Joule-Thomson Cooling Due to CO2 Injection into Natural Gas Reservoirs

    OpenAIRE

    Oldenburg, Curtis M.

    2006-01-01

    Depleted natural gas reservoirs are a promising target for Carbon Sequestration with Enhanced Gas Recovery (CSEGR). The focus of this study is on evaluating the importance of Joule-Thomson cooling during CO2 injection into depleted natural gas reservoirs. Joule-Thomson cooling is the adiabatic cooling that accompanies the expansion of a real gas. If Joule-Thomson cooling were extreme, injectivity and formation permeability could be altered by the freezing of residual water, formation of ...

  2. Gas turbine cooling modeling - Thermodynamic analysis and cycle simulations

    Energy Technology Data Exchange (ETDEWEB)

    Jordal, Kristin

    1999-02-01

    Considering that blade and vane cooling are a vital point in the studies of modern gas turbines, there are many ways to include cooling in gas turbine models. Thermodynamic methods for doing this are reviewed in this report, and, based on some of these methods, a number of model requirements are set up and a Cooled Gas Turbine Model (CGTM) for design-point calculations of cooled gas turbines is established. Thereafter, it is shown that it is possible to simulate existing gas turbines with the CGTM. Knowledge of at least one temperature in the hot part of the turbine (TET, TRIT or possibly TIT) is found to be vital for a complete heat balance over the turbine. The losses, which are caused by the mixing of coolant and main flow, are in the CGTM considered through a polytropic efficiency reduction factor S. Through the study of S, it can be demonstrated that there is more to gain from coolant reduction in a small and/or old turbine with poor aerodynamics, than there is to gain in a large, modern turbine, where the losses due to interaction between coolant and main flow are, relatively speaking, small. It is demonstrated, at the design point (TET=1360 deg C, {pi}=20) for the simple-cycle gas turbine, that heat exchanging between coolant and fuel proves to have a large positive impact on cycle efficiency, with an increase of 0.9 percentage points if all of the coolant passes through the heat exchanger. The corresponding improvement for humidified coolant is 0.8 percentage points. A design-point study for the HAT cycle shows that if all of the coolant is extracted after the humidification tower, there is a decrease in coolant requirements of 7.16 percentage points, from 19.58% to 12.52% of the compressed air, and an increase in thermal efficiency of 0.46 percentage points, from 53.46% to 53.92%. Furthermore, it is demonstrated with a TET-parameter variation, that the cooling of a simple-cycle gas turbine with humid air can have a positive effect on thermal efficiency

  3. Intense Atomic and Molecular Beams via Neon Buffer Gas Cooling

    CERN Document Server

    Patterson, David; Doyle, John M

    2008-01-01

    We realize a continuous guided beam of cold deuterated ammonia with a flux of 3e11 ND3 molecules/s and a continuous free-space beam of cold potassium with a flux of 1e16 K atoms/s. A novel feature of the buffer gas source used to produce these beams is cold neon, which, due to intermediate Knudsen number beam dynamics, produces a forward velocity and low-energy tail that is comparable to much colder helium-based sources. We expect this source to be trivially generalizable to a very wide range of atomic and molecular species with significant vapor pressure below 1000 K. This source has properties that make it a good starting point for laser cooling of molecules or atoms, cold collision studies, trapping, or nonlinear optics in buffer-gas-cooled atomic or molecular gases.

  4. Flue gas injection control of silica in cooling towers.

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Patrick Vane; Anderson, Howard L., Jr.; Altman, Susan Jeanne

    2011-06-01

    Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.

  5. High-Temperature Gas-Cooled Test Reactor Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James William [Idaho National Laboratory; Bayless, Paul David [Idaho National Laboratory; Nelson, Lee Orville [Idaho National Laboratory; Gougar, Hans David [Idaho National Laboratory; Kinsey, James Carl [Idaho National Laboratory; Strydom, Gerhard [Idaho National Laboratory; Kumar, Akansha [Idaho National Laboratory

    2016-04-01

    A point design has been developed for a 200 MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technological readiness level, licensing approach and costs.

  6. Free cooling of the one-dimensional wet granular gas.

    Science.gov (United States)

    Zaburdaev, V Yu; Brinkmann, M; Herminghaus, S

    2006-07-07

    The free cooling behavior of a wet granular gas is studied in one dimension. We employ a particularly simple model system in which the interaction of wet grains is characterized by a fixed energy loss assigned to each collision. Macroscopic laws of energy dissipation and cluster formation are studied on the basis of numerical simulations and mean-field analytical calculations. We find a number of remarkable scaling properties which may shed light on earlier unexplained results for related systems.

  7. Comparison of advanced cooling technologies efficiency depending on outside temperature

    Energy Technology Data Exchange (ETDEWEB)

    Blaise Hamanaka; Haihua Zhao; Phil Sharpe

    2009-09-01

    In some areas, water availability is a serious problem during the summer and could disrupt the normal operation of thermal power plants which needs large amount of water to operate. Moreover, when water quantities are sufficient, there can still be problem created by the waste heat rejected into the water which is regulated in order to limit the impact of thermal pollution on the environment. All these factors can lead to a decrease of electricity production during the summer and during peak hours, when electricity is the most needed. In order to deal with these problems, advanced cooling technologies have been developed and implemented to reduce water consumption and withdrawals but with an effect in the plant efficiency. This report aims at analyzing the efficiency of several cooling technologies with a fixed power plant design and so to produce a reference to be able to compare them.

  8. Advanced Natural Gas Reciprocating Engine(s)

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  9. The formation and physical origin of highly ionized cooling gas

    CERN Document Server

    Bordoloi, Rongmon; Norman, Colin A

    2016-01-01

    We present a physically clear cooling flow theory that explains the origin of warm diffuse gas seen primarily as highly ionized absorption line systems in the spectra of background sources. We predict the observed column densities of several highly ionized transitions such as O VI, O VII, Ne VIII, N V, and Mg X; and present a unified comparison of the model predictions with absorption lines seen in the Milky Way disk, Milky Way halo, starburst galaxies, the circumgalactic medium and the intergalactic medium at low and high redshifts. We show that diffuse gas seen in such diverse environments can be simultaneously explained by a simple model of radiatively cooling gas. We show that most of such absorption line systems are consistent with being collisionally ionized, and estimate the maximum likelihood temperature of the gas in each observation. This model satisfactorily explains why O VI is regularly observed around star-forming low-z L* galaxies, and why N V is rarely seen around the same galaxies. We predict...

  10. Decay Heat Removal in GEN IV Gas-Cooled Fast Reactors

    Directory of Open Access Journals (Sweden)

    Lap-Yan Cheng

    2009-01-01

    Full Text Available The safety goal of the current designs of advanced high-temperature thermal gas-cooled reactors (HTRs is that no core meltdown would occur in a depressurization event with a combination of concurrent safety system failures. This study focused on the analysis of passive decay heat removal (DHR in a GEN IV direct-cycle gas-cooled fast reactor (GFR which is based on the technology developments of the HTRs. Given the different criteria and design characteristics of the GFR, an approach different from that taken for the HTRs for passive DHR would have to be explored. Different design options based on maintaining core flow were evaluated by performing transient analysis of a depressurization accident using the system code RELAP5-3D. The study also reviewed the conceptual design of autonomous systems for shutdown decay heat removal and recommends that future work in this area should be focused on the potential for Brayton cycle DHRs.

  11. Compatibility of gas turbine materials with steam cooling

    Energy Technology Data Exchange (ETDEWEB)

    Desai, V.; Tamboli, D.; Patel, Y. [University of Central Florida, Orlando, FL (United States). Dept. of Mechanical and Aerospace Engineering

    1995-12-31

    Objective is to investigate performance of gas turbine materials in steam environment and evaluate remedial measures for alleviating the severity of the problem. Three superalloys commonly used in gas turbines were exposed to 3 steam environments containing different impurity levels for 2 to 6 months. Results: Cr2O3-forming alloys containing 1-4% Al such as IN 738 are susceptible to heavy internal oxidation of Al. High Al (>5%) alloys in which continuous Al2O3 scale can be formed, may not be susceptible to such attack. Deposition of salts from steam will accentuate hot corrosion problems. Alloys with higher Cr content such as X-45 are generally less prone to hot corrosion. The greater damage observed in IN 617 make this alloy less attractive for gas turbines with steam cooling. Electrochemical impedance spectroscopy is a good nondestructive method to evaluate microstructural damage.

  12. Analysis of advanced solar hybrid desiccant cooling systems for buildings

    Energy Technology Data Exchange (ETDEWEB)

    Schlepp, D.; Schultz, K.

    1984-10-01

    This report describes an assessment of the energy savings possible from developing hybrid desiccant/vapor-compression air conditioning systems. Recent advances in dehumidifier design for solar desiccant cooling systems have resulted in a dehumidifier with a low pressure drop and high efficiency in heat and mass transfer. A recent study on hybrid desiccant/vapor compression systems showed a 30%-80% savings in resource energy when compared with the best conventional systems with vapor compression. A system consisting of a dehumidifier with vapor compression subsystems in series was found to be the simplest and best overall performer.

  13. Advances in Laser Cooling of Thulium-Doped Glass

    Science.gov (United States)

    2003-05-01

    conversion,’’ Appl. Phys. Lett. 75, 1258–1260 (1999). 21. L. Wetenkamp, G. F. West, and H. Tobben, ‘‘Optical proper- ties of rare earth-doped ZBLAN glasses ...properties of Tm31 in ZBLAN fluoride glass . Part 2. Judd-Ofelt parameters,’’ Phys. Chem. Glasses 36, 139–140 (1995). 38. M. J. Weber, ‘‘Laser excited...Advances in laser cooling of thulium-doped glass C. W. Hoyt, M. P. Hasselbeck, and M. Sheik-Bahae Department of Physics and Astronomy, University of

  14. Heat transfer problems in gas-cooled solid blankets

    Energy Technology Data Exchange (ETDEWEB)

    Fillo, J.A.; Powell, J.R.

    1976-01-01

    In all fusion reactors using the deuterium-tritium fuel cycle, a large fraction approximately 80 percent of the fusion energy will be released as approximately 14 MeV neutrons which must be slowed down in a relatively thick blanket surrounding the plasma, thereby, converting their kinetic energy to high temperature heat which can be continuously removed by a coolant stream and converted in part to electricity in a conventional power turbine. Because of the primary goal of achieving minimum radioactivity, to date Brookhaven blanket concepts have been restricted to the use of some form of solid lithium, with inert gas-cooling and in some design cases, water-cooling of the shell structure. Aluminum and graphite have been identified as very promising structural materials for fusion blankets, and conceptual designs based on these materials have been made. Depending on the thermal loading on the ''first'' wall which surrounds the plasma as well as blanket design, heat transfer problems may be noticeably different in gas-cooled solid blankets. Approaches to solution of heat removal problems as well as explanation of: (a) the after-heat problems in blankets; (b) tritium breeding in solids; and (c) materials selection for radiation shields relative to the minimum activity blanket efforts at Brookhaven are discussed.

  15. Improvements on cool gas generators and their application in space propulsion systems

    NARCIS (Netherlands)

    Sanders, H.M.; Schuurbiers, C.A.H.; Vandeberg, R.J.

    2014-01-01

    Cool Gas Generators are an innovative means to store gas which can be used in propulsion and pressurization systems but also for inflatable structures and terrestrial applications. In Cool Gas Generators, the gas is stored chemically, without pressure or leakage and with a long life time without mai

  16. Advancing agricultural greenhouse gas quantification*

    Science.gov (United States)

    Olander, Lydia; Wollenberg, Eva; Tubiello, Francesco; Herold, Martin

    2013-03-01

    given to methods appropriate to low-income countries, where strategies are needed for getting robust data with extremely limited resources in order to support national mitigation planning within widely accepted standards and thus provide access to essential international support, including climate funding. Managing agricultural emissions needs to occur in tandem with managing for agricultural productivity, resilience to climate change, and ecosystem impacts. Management decisions and priorities will require measures and information that identify GHG efficiencies in production and reduce inputs without reducing yields, while addressing climate resilience and maintaining other essential environmental services, such as water quality and support for pollinators. Another set of papers in this issue considers the critical synergies and tradeoffs possible between these multiple objectives of mitigation, resilience, and production efficiency to help us understand how we need to tackle these in our quantification systems. Significant capacity to quantify greenhouse gases is already built, and with some near-term strategic investment, could become an increasingly robust and useful tool for planning and development in the agricultural sector around the world. Acknowledgments The Climate Change Agriculture and Food Security Program of the Consultative Group on International Agricultural Research, the Technical Working Group on Agricultural Greenhouse Gases (T-AGG) at Duke University's Nicholas Institute for Environmental Policy Solutions, and the United Nations Food and Agriculture Organization (FAO) have come together to guide the development of this focus issue and associated activities and papers, given their common desire to improve our understanding of the state of agricultural greenhouse gas (GHG) quantification and to advance ideas for building data and methods that will help mitigation policy and programs move forward around the world. We thank the David and Lucile Packard

  17. High-pressure propulsion - advanced concepts for cooling

    Science.gov (United States)

    Schoerman, Leonard

    The state-of-the-art liquid propellant cooled combustion chambers utilized in the space shuttle are third-generation designs which have evolved from a continuing demand for higher operating pressure and aircraft-type reusability. History has shown that major advances in cooling occur in approximately ten-year cycles, with each cycle providing a nominal 400% increase in operating pressure and/or a higher degree of reusability. The previous technologies include the first-generation double-wall steel jackets used in the 220 psi V-2 and Aerobee, and the second generation wire-wrapped double tapered tubular assemblies typical of the 800 psi Titan I, II, and III, and 1000 psi F-1 engines. The third-generation designs utilize milled slot, high thermal conductivity liners and electrodeposited nickel closures. The space shuttle main engine operating at 3200 psia is adequate for individual flights; however, the desired goal of 55 service-free missions has yet to be realized. Future single-stage-to-orbit propulsion concepts can benefit from a further increase in operating pressures to 6000 to 10,000 psi combined with engine reuse capabilities in excess of the 55 flight goals of the space shuttle. A fourth-generation approach will be required to attain these more ambitious goals. These new designs will require a combination of cooling processes, including regenerative and transpiration, combined with improved high-temperature materials and new fabrication techniques. The limitations of the third-generation designs, the impact of propellant/coolant selection, and the approaches for the coming fourth-generation cooling technologies are discussed.

  18. Beam cooling using a gas-filled RFQ ion guide

    CERN Document Server

    Henry, S; De Saint-Simon, M; Jacotin, M; Képinski, J F; Lunney, M D

    1999-01-01

    A radiofrequency quadrupole mass filter is being developed for use as a high-transmission beam cooler by operating it in buffer gas at high pressure. Such a device will increase the sensitivity of on-line experiments that make use of weakly produced radioactive ion beams. We present simulations and some preliminary measurements for a device designed to cool the beam for the MISTRAL RF mass spectrometer on- line at ISOLDE. The work is carried out partly within the frame of the European Community research network: EXOTRAPS. (9 refs).

  19. Evaluation of Gas-Cooled Pressurized Phosphoric Acid Fuel Cells for Electric Utility Power Generation

    Science.gov (United States)

    Faroque, M.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas-cooling was already demonstrated in atmospheric pressure stacks. Theoretical and experimental investigations of gas-cooling for pressurized PAFC are presented. Two approaches to gas cooling, Distributed Gas-Cooling (DIGAS) and Separated Gas-Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  20. Evaluation of gas cooling for pressurized phosphoric acid fuel cell stacks

    Science.gov (United States)

    Farooque, M.; Skok, A. J.; Maru, H. C.; Kothmann, R. E.; Harry, R. W.

    1983-01-01

    Gas cooling is a more reliable, less expensive and a more simple alternative to conventional liquid cooling for heat removal from the phosphoric acid fuel cell (PAFC). The feasibility of gas cooling has already been demonstrated in atmospheric pressure stacks. This paper presents theoretical and experimental investigation of gas cooling for pressurized PAFC. Two approaches to gas cooling, Distributed Gas Cooling (DIGAS) and Separated Gas Cooling (SGC) were considered, and a theoretical comparison on the basis of cell performance indicated SGC to be superior to DIGAS. The feasibility of SGC was experimentally demonstrated by operating a 45-cell stack for 700 hours at pressure, and determining thermal response and the effect of other related parameters.

  1. Porous nuclear fuel element for high-temperature gas-cooled nuclear reactors

    Science.gov (United States)

    Youchison, Dennis L.; Williams, Brian E.; Benander, Robert E.

    2011-03-01

    Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.

  2. Porous nuclear fuel element with internal skeleton for high-temperature gas-cooled nuclear reactors

    Science.gov (United States)

    Youchison, Dennis L.; Williams, Brian E.; Benander, Robert E.

    2013-09-03

    Porous nuclear fuel elements for use in advanced high temperature gas-cooled nuclear reactors (HTGR's), and to processes for fabricating them. Advanced uranium bi-carbide, uranium tri-carbide and uranium carbonitride nuclear fuels can be used. These fuels have high melting temperatures, high thermal conductivity, and high resistance to erosion by hot hydrogen gas. Tri-carbide fuels, such as (U,Zr,Nb)C, can be fabricated using chemical vapor infiltration (CVI) to simultaneously deposit each of the three separate carbides, e.g., UC, ZrC, and NbC in a single CVI step. By using CVI, the nuclear fuel may be deposited inside of a highly porous skeletal structure made of, for example, reticulated vitreous carbon foam.

  3. The DOE advanced gas reactor fuel development and qualification program

    Science.gov (United States)

    Petti, David; Maki, John; Hunn, John; Pappano, Pete; Barnes, Charles; Saurwein, John; Nagley, Scott; Kendall, Jim; Hobbins, Richard

    2010-09-01

    The high outlet temperatures and high thermal-energy conversion efficiency of modular high-temperature gas-cooled reactors (HTGRs) enable an efficient and cost-effective integration of the reactor system with non-electricity-generation applications, such as process heat and/or hydrogen production, for the many petrochemical and other industrial processes that require temperatures between 300°C and 900°C. The U.S. Department of Energy (DOE) has selected the HTGR concept for the Next Generation Nuclear Plant (NGNP) Project as a transformative application of nuclear energy that will demonstrate emissions-free nuclear-assisted electricity, process heat, and hydrogen production, thereby reducing greenhouse-gas emissions and enhancing energy security. The objective of the DOE Advanced Gas Reactor (AGR) Fuel Development and Qualification program is to qualify tristructural isotropic (TRISO)-coated particle fuel for use in HTGRs. An overview of the program and recent progress is presented.

  4. Gas-cooled reactors: the importance of their development

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.

    1979-06-01

    The nearest term GCR is the steam-cycle HTGR, which can be used for both power and process steam production. Use of SC-HTGRs permits timely introduction of thorium fuel cycles and of high-thermal-efficiency reactors, decreasing the need for mined U/sub 3/O/sub 8/ before arrival of symbiotic fueling of fast-thermal reactor systems. The gas-turbine HTGR offers prospects of lower capital costs than other nuclear reactors, but it appears to require longer and more costly development than the SC-HTGR. Accelerated development of the GT-HTGR is needed to gain the advantages of timely introduction. The Gas-Cooled Fast Breeder Reactor (GCFR) offers the possibility of fast breeder reactors with lower capital costs and with higher breeding ratios from oxide fuels. The VHTR provides high-temperature heat for hydrogen production.

  5. Multidisciplinary design optimization of film-cooled gas turbine blades

    Directory of Open Access Journals (Sweden)

    Talya Shashishekara S.

    1999-01-01

    Full Text Available Design optimization of a gas turbine blade geometry for effective film cooling toreduce the blade temperature has been done using a multiobjective optimization formulation. Three optimization formulations have been used. In the first, the average blade temperature is chosen as the objective function to be minimized. An upper bound constraint has been imposed on the maximum blade temperature. In the second, the maximum blade temperature is chosen as the objective function to be minimized with an upper bound constraint on the average blade temperature. In the third formulation, the blade average and maximum temperatures are chosen as objective functions. Shape optimization is performed using geometric parameters associated with film cooling and blade external shape. A quasi-three-dimensional Navier–Stokes solver for turbomachinery flows is used to solve for the flow field external to the blade with appropriate modifications to incorporate the effect of film cooling. The heat transfer analysis for temperature distribution within the blade is performed by solving the heat diffusion equation using the finite element method. The multiobjective Kreisselmeier–Steinhauser function approach has been used in conjunction with an approximate analysis technique for optimization. The results obtained using both formulations are compared with reference geometry. All three formulations yield significant reductions in blade temperature with the multiobjective formulation yielding largest reduction in blade temperature.

  6. Primordial gas cooling behind shock waves in merging halos

    CERN Document Server

    Vasiliev, E O; Shchekinov, Yu.A.

    2006-01-01

    We investigate thermal regime of the baryons behind shock waves arising in the process of virialization of dark matter halos. We find a fraction of the shocked gas cooled by radiation of HD molecules down to the temperature of the cosmic microwave background (CMB): this fraction increases sharply from about $f_{\\rm c}\\sim 10^{-3}$ for dark halos of $M=5\\times 10^7\\msun$ to $\\sim 0.1$ for halos with $M=10^8\\msun$ at $z=10$. We show, however, that further increase of the mass does not lead to a significant growth of $f_{\\rm c}$ -- the assymptotic value for $M\\gg 10^8\\msun$ is of 0.2. We estimate star formation rate associated with such shock waves, and show that it can be a small but not negligible fraction of the star formation connected with cooling by HI and H$_2$. We argue that extremely metal-poor low-mass stars in the Milky Way may have been formed from primordial gas behind such shocks.

  7. Application of Hastelloy X in gas-cooled reactor systems

    Energy Technology Data Exchange (ETDEWEB)

    Brinkman, C.R.; Rittenhouse, P.L.; Corwin, W.R.; Strizak, J.P.; Lystrup, A.; DiStefano, J.R.

    1976-10-01

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data are reported. Properties of concern include tensile, creep, creep-rupture, fatigue, creep-fatigue interaction, subcritical crack growth, thermal stability, and the influence of helium environments with controlled amounts of impurities on these properties. In order to develop these properties in helium environments that are expected to be prototypic of HTGR operating conditions, it was necessary to construct special environmental test systems. Details of construction and operating parameters are described. Interim results from tests designed to determine the above properties are presented. To date a fairly extensive amount of information has been generated on this material at Oak Ridge National Laboratory and elsewhere concerning behavior in air, which is reviewed. However, only limited data are available from tests conducted in helium. Comparisons of the fatigue and subcritical growth behavior in air between Hastelloy X and a number of other structural alloys are given.

  8. ADVANCED HOT GAS FILTER DEVELOPMENT

    Energy Technology Data Exchange (ETDEWEB)

    Matthew R. June; John L. Hurley; Mark W. Johnson

    1999-04-01

    Iron aluminide hot gas filters have been developed using powder metallurgy techniques to form seamless cylinders. Three alloys were short-term corrosion tested in simulated IGCC atmospheres with temperatures between 925 F and 1200 F with hydrogen sulfide concentrations ranging from 783 ppm{sub v} to 78,300 ppm{sub v}. Long-term testing was conducted for 1500 hours at 925 F with 78,300 ppm{sub v}. The FAS and FAL alloys were found to be corrosion resistant in the simulated environments. The FAS alloy has been commercialized.

  9. A gas-cooled reactor surface power system

    Science.gov (United States)

    Lipinski, Ronald J.; Wright, Steven A.; Lenard, Roger X.; Harms, Gary A.

    1999-01-01

    A human outpost on Mars requires plentiful power to assure survival of the astronauts. Anywhere from 50 to 500 kW of electric power (kWe) will be needed, depending on the number of astronauts, level of scientific activity, and life-cycle closure desired. This paper describes a 250-kWe power system based on a gas-cooled nuclear reactor with a recuperated closed Brayton cycle conversion system. The design draws upon the extensive data and engineering experience developed under the various high-temperature gas cooled reactor programs and under the SP-100 program. The reactor core is similar in power and size to the research reactors found on numerous university campuses. The fuel is uranium nitride clad in Nb1%Zr, which has been extensively tested under the SP-100 program. The fuel rods are arranged in a hexagonal array within a BeO block. The BeO softens the spectrum, allowing better use of the fuel and stabilizing the geometry against deformation during impact or other loadings. The system has a negative temperature feedback coefficient so that the power level will automatically follow a variable load without the need for continuous adjustment of control elements. Waste heat is removed by an air-cooled heat exchanger using cold Martian air. The amount of radioactivity in the reactor at launch is very small (less than a Curie, and about equal to a truckload of uranium ore). The system will need to be engineered so that criticality can not occur for any launch accident. This system is also adaptable for electric propulsion or life-support during transit to and from Mars.

  10. Development status and operational features of the high temperature gas-cooled reactor. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Winkleblack, R.K.

    1976-04-01

    The objective of this study is to investigate the maturity of HTR-technology and to look out for possible technical problems, concerning introduction of large HTR power plants into the market. Further state and problems of introducing and closing the thorium fuel cycle is presented and judged. Finally, the state of development of advanced HTR-concepts for electricity production, the direct cycle HTR with helium turbine, and the gas-cooled fast breeder is discussed. In preparing the study, both HTR concepts with spherical and block-type fuel elements have been considered.

  11. Combustion modeling in advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    Smoot, L.D.; Hedman, P.O.; Fletcher, T.H. [Brigham Young Univ., Provo, UT (United States)] [and others

    1995-10-01

    The goal of the U.S. Department of Energy`s Advanced Turbine Systems (ATS) program is to help develop and commercialize ultra-high efficiency, environmentally superior, and cost competitive gas turbine systems for base-load applications in the utility, independent power producer, and industrial markets. Combustion modeling, including emission characteristics, has been identified as a needed, high-priority technology by key professionals in the gas turbine industry.

  12. Advanced Pumps and Cold Plates for Two-Phase Cooling Loops Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced instruments used for earth science missions require improved cooling systems to remove heat from high power electronic components and maintain tight...

  13. Advanced Natural Gas Reciprocating Engine(s)

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Doris; Boucher, Cheryl

    2009-09-30

    Energy independence and fuel savings are hallmarks of the nation’s energy strategy. The advancement of natural gas reciprocating engine power generation technology is critical to the nation’s future. A new engine platform that meets the efficiency, emissions, fuel flexibility, cost and reliability/maintainability targets will enable American manufacturers to have highly competitive products that provide substantial environmental and economic benefits in the US and in international markets. Along with Cummins and Waukesha, Caterpillar participated in a multiyear cooperative agreement with the Department of Energy to create a 50% efficiency natural gas powered reciprocating engine system with a 95% reduction in NOx emissions by the year 2013. This platform developed under this agreement will be a significant contributor to the US energy strategy and will enable gas engine technology to remain a highly competitive choice, meeting customer cost of electricity targets, and regulatory environmental standard. Engine development under the Advanced Reciprocating Engine System (ARES) program was divided into phases, with the ultimate goal being approached in a series of incremental steps. This incremental approach would promote the commercialization of ARES technologies as soon as they emerged from development and would provide a technical and commercial foundation of later-developing technologies. Demonstrations of the Phase I and Phase II technology were completed in 2004 and 2008, respectively. Program tasks in Phase III included component and system development and testing from 2009-2012. Two advanced ignition technology evaluations were investigated under the ARES program: laser ignition and distributed ignition (DIGN). In collaboration with Colorado State University (CSU), a laser ignition system was developed to provide ignition at lean burn and high boost conditions. Much work has been performed in Caterpillar’s DIGN program under the ARES program. This work

  14. Physics with Cold Molecules Using Buffer Gas Cooling: Precision Measurement, Collisions, and Laser Cooling

    Science.gov (United States)

    Hutzler, Nicholas R.; Doyle, John M.

    2014-06-01

    Cryogenic buffer gas cooled beams and cells can be used to study many species, from atoms and polar molecules to biomolecules. We report on recent applications of this technique to improve the limit on the electron electric dipole moment [1], load polar molecules into a magnetic trap through optical pumping [2], perform chirally sensitive microwave spectroscopy on polyatomic molecules [3], progress towards magneto-optical trapping of polar molecules [4], and studies of atom-molecule sticking [5]. [1] The ACME Collaboration: J. Baron et al., Science 343, p. 269 (2014) [2] B. Hemmerling et al., arXiv:1310.2669, to appear in Phys. Rev. Lett. [3] D. Patterson, M. Schnell, & J. M. Doyle, Nature 497, p. 475 (2013) [4] H. Lu et al., arXiv:1310.3239, to appear in New. J. Phys. [5] J. Piskorski et al., under preparation

  15. A He-gas Cooled, Stationary Granular Target

    CERN Document Server

    Pugnat, P

    2003-01-01

    In the CERN approach to the design of a neutrino factory, the repetition frequency of the proton beam is high enough to consider stationary solid targets as a viable solution for multi-MW beams. The target consists of high density tantalum spheres of 2 mm diameter which can efficiently be cooled by passing a high mass flow He-gas stream through the voids between the Ta-granules. Very small thermal shocks and stresses will arise in this fine grained structure due to the relatively long burst of 3.3 ms from the SPL-proton linac. In a quadruple target system where each target receives only one quarter of the total beam power of 4 MW, conservative temperature levels and adequate lifetimes of the target are estimated in its very high radiation environment. A conceptual design of the integration of the target into the magnetic horn-pion-collector is presented.

  16. Computational Fluid Dynamics Analysis of Very High Temperature Gas-Cooled Reactor Cavity Cooling System

    Energy Technology Data Exchange (ETDEWEB)

    Frisani, Angelo; Hassan, Yassin A; Ugaz, Victor M

    2010-11-02

    The design of passive heat removal systems is one of the main concerns for the modular very high temperature gas-cooled reactors (VHTR) vessel cavity. The reactor cavity cooling system (RCCS) is a key heat removal system during normal and off-normal conditions. The design and validation of the RCCS is necessary to demonstrate that VHTRs can survive to the postulated accidents. The computational fluid dynamics (CFD) STAR-CCM+/V3.06.006 code was used for three-dimensional system modeling and analysis of the RCCS. A CFD model was developed to analyze heat exchange in the RCCS. The model incorporates a 180-deg section resembling the VHTR RCCS experimentally reproduced in a laboratory-scale test facility at Texas A&M University. All the key features of the experimental facility were taken into account during the numerical simulations. The objective of the present work was to benchmark CFD tools against experimental data addressing the behavior of the RCCS following accident conditions. Two cooling fluids (i.e., water and air) were considered to test the capability of maintaining the RCCS concrete walls' temperature below design limits. Different temperature profiles at the reactor pressure vessel (RPV) wall obtained from the experimental facility were used as boundary conditions in the numerical analyses to simulate VHTR transient evolution during accident scenarios. Mesh convergence was achieved with an intensive parametric study of the two different cooling configurations and selected boundary conditions. To test the effect of turbulence modeling on the RCCS heat exchange, predictions using several different turbulence models and near-wall treatments were evaluated and compared. The comparison among the different turbulence models analyzed showed satisfactory agreement for the temperature distribution inside the RCCS cavity medium and at the standpipes walls. For such a complicated geometry and flow conditions, the tested turbulence models demonstrated that the

  17. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Fleeter, S.; Lawless, P.B. [Purdue Univ., West Lafayette, IN (United States)

    1995-10-01

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. This requires experiments in appropriate research facilities in which complete flow field data, not only point measurements, are obtained and analyzed. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows.

  18. Recent Advance in Thermoelectric Devices for Electronics Cooling

    Science.gov (United States)

    Wang, Peng

    Thermal management of on-chip hot spot, with a heat flux of around 1000 W/cm2, has become one of the major challenges in the development of next-generation microprocessors. Solid state thermoelectric cooler (TEC) offers great promise for hot spot thermal management because of their compact structure, fast response, high reliability, localized cooling, and high flux removal capability. To date TEC has received great attentions in electronics cooling community as one of the potential hot spot cooling solutions. In this paper, recent development and application of hot spot cooling strategies based on micro thermoelectric technologies will be reviewed and discussed, three hot spot cooling concepts, including thinfilm thermoelectric cooling, mini-contact cooling, and semiconductor selfcooling in silicon substrate and germanium substrate will be discussed. The advantages and disadvantages of these on-chip cooling solutions for high flux hot spots will be evaluated.

  19. Low pressure cooling seal system for a gas turbine engine

    Science.gov (United States)

    Marra, John J

    2014-04-01

    A low pressure cooling system for a turbine engine for directing cooling fluids at low pressure, such as at ambient pressure, through at least one cooling fluid supply channel and into a cooling fluid mixing chamber positioned immediately downstream from a row of turbine blades extending radially outward from a rotor assembly to prevent ingestion of hot gases into internal aspects of the rotor assembly. The low pressure cooling system may also include at least one bleed channel that may extend through the rotor assembly and exhaust cooling fluids into the cooling fluid mixing chamber to seal a gap between rotational turbine blades and a downstream, stationary turbine component. Use of ambient pressure cooling fluids by the low pressure cooling system results in tremendous efficiencies by eliminating the need for pressurized cooling fluids for sealing this gap.

  20. Experimental and numerical investigation of heat transfer and pressure drop for innovative gas cooled systems

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, R., E-mail: rodrigo.leija@kit.edu [Karlsruhe Institute of Technology, Institute for Neutron Physics and Reactor Technology, Hermann-von-Helmholtz No. 1, 76344 Eggenstein-Leopoldshafen (Germany); Buchholz, S. [Gesellschaft für Anlagen- und Reaktorsicherheit GRS mbH, Boltzmannstraße 2, 85748 Garching (Germany); Suikkanen, H. [Lappeenranta University of Technology, LUT Energy, PO Box 20, FI-53851 Lappeenranta (Finland)

    2015-08-15

    Highlights: • Experimental results of the L-STAR within the first stage of THINS project. • CFD validation for the heat transfer and pressure losses in innovative gas cooled systems. • The results indicate a strong dependency Turbulent Prandtl at the rod wall temperature distribution. • Gas loop facility suitable for the investigation of thermohydraulic issues of GFR, however there might be flow instabilities when flow is very low. - Abstract: Heat transfer enhancement through turbulence augmentation is recognized as a key factor for improving the safety and economic conditions in the development of both critical and subcritical innovative advanced gas cooled fast reactors (GFR) and transmutation systems. The L-STAR facility has been designed and erected at the Karlsruhe Institute of Technology (KIT) to study turbulent flow behavior and its heat transfer enhancement characteristics in gas cooled annular channels under a wide range of conditions. The test section consists of an annular hexagonal cross section channel with an inner electrical heater rod element, placed concentrically within the test section, which seeks to simulate the flow area of a fuel rod element in a GFR. The long term objective of the experimental study is to investigate and improve the understanding of complex turbulent convective enhancement mechanisms as well as the friction loss penalties of roughened fuel rods compared to smooth ones and to generate an accurate database for further development of physical models. In the first step, experimental results of the fluid flow with uniform heat release conditions for the smooth heater rod are presented. The pressure drops, as well as the axial temperature profiles along the heater rod surface have been measured at Reynolds numbers in the range from 4000 to 35,000. The experimental results of the first stage were compared with independently conducted CFD analyses performed at Lappeenranta University of Technology (LUT) with the code ANSYS

  1. Steady state cooling flow models with gas loss for normal elliptical galaxies

    Science.gov (United States)

    Sarazin, Craig L.; Ashe, Gregory A.

    1989-01-01

    A grid of cooling flow models for the hot gas in normal elliptical galaxies is calculated, including the loss of gas due to inhomogeneous cooling. The loss process is modeled as a distributed sink for the gas with the rate of loss being proportional to the local cooling rate. The cooling flow models with gas loss have smaller sonic radii, smaller inflow rates in their central regions, lower densities, and higher temperatures than homogeneous models. The reduction in the amount of hot gas flowing into the center of the models brings the models into much better agreement with the observed X-ray surface brightness profiles of elliptical galaxies. However, there is a large dispersion in the observed X-ray luminosities of ellipticals, and this cannot be explained by variations in the efficiency of gas loss. The gas-loss models have X-ray surface brightness profiles which are much less centrally peaked than the no-gas-loss models.

  2. A cryogenic buffer gas cooled beam of BaH for molecular laser cooling and ultracold fragmentation

    Science.gov (United States)

    Iwata, Geoffrey; Tarallo, Marco G.; Soerensen, Fabian; Zelevinsky, Tanya

    2015-05-01

    Laser cooled and trapped molecules promise many possibilities to explore a variety of fields such as many-body physics, quantum collisions and dissociation, and precision measurement. We report on an experiment for cooling and trapping barium monohydride (BaH) diatomic molecules. We present a cryogenic buffer gas cooling apparatus for producing a 4 K beam of BaH, and describe the laser cooling schemes necessary to load a molecular magneto-optical trap from that beam. Current progress includes identification of the cooling transitions in the BaH B2 Σ molecules and construction of the molecular beam. The large mass ratio of constituent atoms in BaH makes this system attractive for future studies of ultracold fragmentation, potentially resulting in samples of ultracold hydrogen atoms.

  3. Role of gas cooling in tomorrow`s energy services industry

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, P.J.

    1997-04-01

    This article discusses the marketing approach and opportunities for suppliers and manufacturers of gas cooling equipment to partner with energy service companies (ESCOs). The author`s viewpoint is that in educating and partnering with ESCOs the gas cooling industry enables their technology to reach its potential in the projects that the ESCOs develop.

  4. Improving fuel cycle design and safety characteristics of a gas cooled fast reactor

    NARCIS (Netherlands)

    van Rooijen, W.F.G.

    2006-01-01

    This research concerns the fuel cycle and safety aspects of a Gas Cooled Fast Reactor, one of the so-called "Generation IV" nuclear reactor designs. The Generation IV Gas Cooled Fast Reactor uses helium as coolant at high temperature. The goal of the GCFR is to obtain a "closed nuclear fuel cycle",

  5. Research and Development of Advanced Gas Turbine

    OpenAIRE

    1989-01-01

    The program “Advanced Gas Turbine” successfully completed in FY 1987, having been started in FY 1978 as a part of the “Moonlight Project”, the National research and development program for energy conservation promoted by the Agency of Industrial Science and Technology, the Ministry of International Trade and Industry. The purpose of this program was to establish the technologies for the combined cycle power generation system, which has an overall thermal efficiency of 55% (LHV), by developing...

  6. Advanced Coal-Fueled Gas Turbine Program

    Energy Technology Data Exchange (ETDEWEB)

    Horner, M.W.; Ekstedt, E.E.; Gal, E.; Jackson, M.R.; Kimura, S.G.; Lavigne, R.G.; Lucas, C.; Rairden, J.R.; Sabla, P.E.; Savelli, J.F.; Slaughter, D.M.; Spiro, C.L.; Staub, F.W.

    1989-02-01

    The objective of the original Request for Proposal was to establish the technological bases necessary for the subsequent commercial development and deployment of advanced coal-fueled gas turbine power systems by the private sector. The offeror was to identify the specific application or applications, toward which his development efforts would be directed; define and substantiate the technical, economic, and environmental criteria for the selected application; and conduct such component design, development, integration, and tests as deemed necessary to fulfill this objective. Specifically, the offeror was to choose a system through which ingenious methods of grouping subcomponents into integrated systems accomplishes the following: (1) Preserve the inherent power density and performance advantages of gas turbine systems. (2) System must be capable of meeting or exceeding existing and expected environmental regulations for the proposed application. (3) System must offer a considerable improvement over coal-fueled systems which are commercial, have been demonstrated, or are being demonstrated. (4) System proposed must be an integrated gas turbine concept, i.e., all fuel conditioning, all expansion gas conditioning, or post-expansion gas cleaning, must be integrated into the gas turbine system.

  7. Modular High Temperature Gas-Cooled Reactor Safety Basis and Approach

    Energy Technology Data Exchange (ETDEWEB)

    David Petti; Jim Kinsey; Dave Alberstein

    2014-01-01

    Various international efforts are underway to assess the safety of advanced nuclear reactor designs. For example, the International Atomic Energy Agency has recently held its first Consultancy Meeting on a new cooperative research program on high temperature gas-cooled reactor (HTGR) safety. Furthermore, the Generation IV International Forum Reactor Safety Working Group has recently developed a methodology, called the Integrated Safety Assessment Methodology, for use in Generation IV advanced reactor technology development, design, and design review. A risk and safety assessment white paper is under development with respect to the Very High Temperature Reactor to pilot the Integrated Safety Assessment Methodology and to demonstrate its validity and feasibility. To support such efforts, this information paper on the modular HTGR safety basis and approach has been prepared. The paper provides a summary level introduction to HTGR history, public safety objectives, inherent and passive safety features, radionuclide release barriers, functional safety approach, and risk-informed safety approach. The information in this paper is intended to further the understanding of the modular HTGR safety approach. The paper gives those involved in the assessment of advanced reactor designs an opportunity to assess an advanced design that has already received extensive review by regulatory authorities and to judge the utility of recently proposed new methods for advanced reactor safety assessment such as the Integrated Safety Assessment Methodology.

  8. Advances in hot gas filtration technology

    Energy Technology Data Exchange (ETDEWEB)

    Weber, C.

    The past decade has seen the introduction of new filter media specifically designed for 'hot-gas' filtration. These media are available as woven or knitted fabrics and as non-wovens, i.e. needled felts. Needlefelted fabrics have proven so highly successful in the dedusting of hot gases that they are widely used nowadays in this new and necessary technology. Hot-gas filtration offers advantages in, for example, the saving or recycling of energy, the elimination of the cooling process, and the short-circuiting of process steps. This paper gives a survey of the types of textile fibres available for hot-gas filtration from the more recently developed organic fibres to refractory fibres. It describes, compares and contrasts their salient properties and lists the uses to which they may be put. It concentrates on such fibres which are generally referred to as 'high performance materials', since they are expected to provide satisfactory performance under extreme conditions of temperature, chemical environment and mechanical stress. It touches on filtration theory governing the collection mechanism. 9 refs., 7 figs., 3 tabs.

  9. Description of the magnox type of gas cooled reactor (MAGNOX)

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, S.E.; Nonboel, E

    1999-05-01

    The present report comprises a technical description of the MAGNOX type of reactor as it has been build in Great Britain. The Magnox reactor is gas cooled (CO{sub 2}) with graphite moderators. The fuels is natural uranium in metallic form, canned with a magnesium alloy called 'Magnox'. The Calder Hall Magnox plant on the Lothian coastline of Scotland, 60 km east of Edinburgh, has been chosen as the reference plant and is described in some detail. Data on the other stations are given in tables with a summary of design data. Special design features are also shortly described. Where specific data for Calder Hall Magnox has not been available, corresponding data from other Magnox plants has been used. The information presented is based on the open literature. The report is written as a part of the NKS/RAK-2 sub-project 3: 'Reactors in Nordic Surroundings', which comprises a description of nuclear power plants neighbouring the Nordic countries. (au)

  10. Analysis of Internal Cooling Geometry Variations in Gas Turbine Blades

    Institute of Scientific and Technical Information of China (English)

    M. Eifel; V. Caspary; H. H(o)nen; P. Jeschke

    2009-01-01

    The present investigation analyzes the effects of major geometrical modifications to the interior of a convection cooled gas turbine rotor blade. The main focus lies on the flow of the leading edge channels and the impact on the heat transfer. An experimental approach is performed with flow visualization via paint injection into water. Also numerical calculations are carried out in two sets, on the one hand water calculations accompanying the experi-ments and on the other hand conjugate heat transfer calculations under realistic engine conditions. The latter cal-culations are still ongoing delivering preliminary results. Five geometry configurations are investigated, three of them with differing turbulator arrangements in the leading edge channels. The operating point of the base configuration is set to Re = 50,000 at the inlet while for the modi-fied geometries the pressure ratio is held constant compared to the base. Among several investigated configurations one could be identified that leads to a heat transfer enhancement in one leading edge channel 7 % larger compared to the base.

  11. Concept of an inherently-safe high temperature gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Hirofumi; Sato, Hiroyuki; Tachibana, Yukio; Kunitomi, Kazuhiko; Ogawa, Masuro [Nuclear Hydrogen and Heat Application Research Center, Japan Atomic Energy Agency, Oarai-machi, Ibaraki-ken, 311-1394 (Japan)

    2012-06-06

    As the challenge to ensure no harmful release of radioactive materials at the accidents by deterministic approach instead to satisfy acceptance criteria or safety goal for risk by probabilistic approach, new concept of advanced reactor, an inherently-safe high temperature gas-cooled reactor, is proposed based on the experience of the operation of the actual High Temperature Gas-cooled Reactor (HTGR) in Japan, High Temperature Engineering Test Reactor (HTTR), and the design of the commercial plant (GTHTR300), utilizing the inherent safety features of the HTGR (i.e., safety features based on physical phenomena). The safety design philosophy of the inherently-safe HTGR for the safety analysis of the radiological consequences is determined as the confinement of radioactive materials is assured by only inherent safety features without engineered safety features, AC power or prompt actions by plant personnel if the design extension conditions occur. Inherent safety features to prevent the loss or degradation of the confinement function are identified. It is proposed not to apply the probabilistic approach for the evaluation of the radiological consequences of the accidents in the safety analysis because no inherent safety features fail for the mitigation of the consequences of the accidents. Consequently, there are no event sequences to harmful release of radioactive materials if the design extension conditions occur in the inherently-safe HTGR concept. The concept and future R and D items for the inherently-safe HTGR are described in this paper.

  12. Theoretical thermodynamics analysis of cooling cycle bu advanced gas absorption using solar energy; Analisis teorico-experimental de un ciclo de refrigeracion por absorcion avanzado gax, operando con energia solar

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, V. E.; Vidal, A. S.; Garcia, C. A.; Garcia-Valladares, O.; Best, R. B.; Hernandez, J. G.; Velazquez, N. L.

    2004-07-01

    In this article a solar system of refrigeration by absorption with heat exchange generator absorber (GAX) was analyzed. A theoretical thermodynamic analysis of the energetic behavior of the GAX absorption system was made. Experimental results were obtained with generation temperatures of 190 and 220 C, the evaporation temperature was set at 9 C and temperatures of cooling fluids (air and water) were set at 30 C and 28 C, respectively. It was possible to appreciate that the GAX effect decrease whether absorber, type falling film, is operated in option of parallel flow and it was increased when the absorber was operated in option of counterflow. (Author)

  13. Demonstration of Enabling Spar-Shell Cooling Technology in Gas Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Downs, James [Florida Turbine Technologies Inc., Jupiter, FL (United States)

    2014-12-29

    In this Advanced Turbine Program-funded Phase III project, Florida Turbine Technologies, Inc. (FTT) has developed and tested, at a pre-commercial prototypescale, spar-shell turbine airfoils in a commercial gas turbine. The airfoil development is based upon FTT’s research and development to date in Phases I and II of Small Business Innovative Research (SBIR) grants. During this program, FTT has partnered with an Original Equipment Manufacturer (OEM), Siemens Energy, to produce sparshell turbine components for the first pre-commercial prototype test in an F-Class industrial gas turbine engine and has successfully completed validation testing. This project will further the commercialization of this new technology in F-frame and other highly cooled turbine airfoil applications. FTT, in cooperation with Siemens, intends to offer the spar-shell vane as a first-tier supplier for retrofit applications and new large frame industrial gas turbines. The market for the spar-shell vane for these machines is huge. According to Forecast International, 3,211 new gas turbines units (in the >50MW capacity size range) will be ordered in ten years from 2007 to 2016. FTT intends to enter the market in a low rate initial production. After one year of successful extended use, FTT will quickly ramp up production and sales, with a target to capture 1% of the market within the first year and 10% within 5 years (2020).

  14. Novel Applications of Buffer-gas Cooling to Cold Atoms, Diatomic Molecules, and Large Molecules

    Science.gov (United States)

    Drayna, Garrett Korda

    Cold gases of atoms and molecules provide a system for the exploration of a diverse set of physical phenomena. For example, cold gasses of magnetically and electrically polar atoms and molecules are ideal systems for quantum simulation and quantum computation experiments, and cold gasses of large polar molecules allow for novel spectroscopic techniques. Buffer-gas cooling is a robust and widely applicable method for cooling atoms and molecules to temperatures of approximately 1 Kelvin. In this thesis, I present novel applications of buffer-gas cooling to obtaining gases of trapped, ultracold atoms and diatomic molecules, as well as the study of the cooling of large organic molecules. In the first experiment of this thesis, a buffer-gas beam source of atoms is used to directly load a magneto-optical trap. Due to the versatility of the buffer-gas beam source, we obtain trapped, sub-milliKelvin gases of four different lanthanide species using the same experimental apparatus. In the second experiment of this thesis, a buffer-gas beam is used as the initial stage of an experiment to directly laser cool and magneto-optically trap the diatomic molecule CaF. In the third experiment of this thesis, buffer-gas cooling is used to study the cooling of the conformational state of large organic molecules. We directly observe conformational relaxation of gas-phase 1,2-propanediol due to cold collisions with helium gas. Lastly, I present preliminary results on a variety of novel applications of buffer-gas cooling, such as mixture analysis, separation of chiral mixtures, the measurement of parity-violation in chiral molecules, and the cooling and spectroscopy of highly unstable reaction intermediates.

  15. AGT101 Advanced Gas Turbine Technology update

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, G.L.; Kidwell, J.R.; Kreiner, D.M.

    1986-01-01

    The Garrett/Ford Advanced Gas Turbine Technology Development Program, designated AGT101, has made significant progress during 1985 encompassing ceramic engine and ceramic component testing. Engine testing has included full speed operation to 100,000 rpm and 1149C (2100F) turbine inlet temperature, initial baseline performance mapping and ceramic combustor start and steady state operation. Over 380 hours of test time have been accumulated on four development engines. High temperature foil bearing coatings have passed rig test and a thick precious metal foil coating selected for engine evaluation. Ceramic structures have been successfully rig tested at 1371C (2500F) for over 27 hours.

  16. Comparative Exergoeconomic Analyses of Gas Turbine Steam Injection Cycles with and without Fogging Inlet Cooling

    OpenAIRE

    Hassan Athari; Saeed Soltani; Marc A. Rosen; Seyed Mohammad Seyed Mahmoudi; Tatiana Morosuk

    2015-01-01

    The results are reported of exergoeconomic analyses of a simple gas turbine cycle without a fogging system (SGT), a simple steam injection gas turbine cycle (STIG), and a steam injection gas turbine cycle with inlet fogging cooler (FSTIG). The results show that (1) a gas-turbine cycle with steam injection and simultaneous cooling has a higher power output than the other considered cycle; (2) at maximum energy efficiency conditions the gas turbine has the highest exergy efficiency of the cycle...

  17. Use of a temperature-initiated passive cooling system (TIPACS) for the modular high-temperature gas-cooled reactor cavity cooling system (RCCS)

    Energy Technology Data Exchange (ETDEWEB)

    Forsberg, C.W.; Conklin, J.; Reich, W.J.

    1994-04-01

    A new type of passive cooling system has been invented (Forsberg 1993): the Temperature-Initiated Passive Cooling System (TIPACS). The characteristics of the TIPACS potentially match requirements for an improved reactor-cavity-cooling system (RCCS) for the modular high-temperature gas-cooled reactor (MHTGR). This report is an initial evaluation of the TIPACS for the MHTGR with a Rankines (steam) power conversion cycle. Limited evaluations were made of applying the TIPACS to MHTGRs with reactor pressure vessel temperatures up to 450 C. These temperatures may occur in designs of Brayton cycle (gas turbine) and process heat MHTGRs. The report is structured as follows. Section 2 describes the containment cooling issues associated with the MHTGR and the requirements for such a cooling system. Section 3 describes TIPACS in nonmathematical terms. Section 4 describes TIPACS`s heat-removal capabilities. Section 5 analyzes the operation of the temperature-control mechanism that determines under what conditions the TIPACS rejects heat to the environment. Section 6 addresses other design and operational issues. Section 7 identifies uncertainties, and Section 8 provides conclusions. The appendixes provide the detailed data and models used in the analysis.

  18. Some Experimental Investigations on Gas Turbine Cooling Performed with Infrared Thermography at Federico II

    Directory of Open Access Journals (Sweden)

    T. Astarita

    2015-01-01

    Full Text Available This paper reviews some experimental measurements of convective heat transfer coefficient distributions which are connected with the cooling of gas turbines, performed by the authors’ research group at the University of Naples Federico II with infrared thermography. Measurements concern impinging jets, cooling of rotating disks, and gas turbine blades, which are either stationary or rotating. The heated thin foil sensor, associated with the detection of surface temperature by means of infrared thermography, is exploited to accurately measure detailed convective heat transfer coefficient maps. The paper also intends to show how to correctly apply the infrared technique in a variety of gas turbines cooling problems.

  19. Heating and cooling with gas-fired heat-pumps; Heizen und Kuehlen mit Gas-Waermepumpen

    Energy Technology Data Exchange (ETDEWEB)

    Stadelmann, M.

    2008-07-01

    This article takes a look at the use of gas-fired absorption heat-pumps in combined cooling and heating applications. Savings in investments and reduced primary energy consumption along with the resulting lower gas costs are noted. The operation of such 'reversible' systems that use ammonia as a working fluid is briefly described. An installation at a filling station in Taverne, Switzerland, is described. A further installation at a gas utility depot in Givisiez, Switzerland, is also looked at. Here, the gas-powered heat-pump system works together with a solar installation to provide space-heating and cooling as well as hot-water preparation.

  20. Economizer Based Data Center Liquid Cooling with Advanced Metal Interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Chainer

    2012-11-30

    A new chiller-less data center liquid cooling system utilizing the outside air environment has been shown to achieve up to 90% reduction in cooling energy compared to traditional chiller based data center cooling systems. The system removes heat from Volume servers inside a Sealed Rack and transports the heat using a liquid loop to an Outdoor Heat Exchanger which rejects the heat to the outdoor ambient environment. The servers in the rack are cooled using a hybrid cooling system by removing the majority of the heat generated by the processors and memory by direct thermal conduction using coldplates and the heat generated by the remaining components using forced air convection to an air- to- liquid heat exchanger inside the Sealed Rack. The anticipated benefits of such energy-centric configurations are significant energy savings at the data center level. When compared to a traditional 10 MW data center, which typically uses 25% of its total data center energy consumption for cooling this technology could potentially enable a cost savings of up to $800,000-$2,200,000/year (assuming electricity costs of 4 to 11 cents per kilowatt-hour) through the reduction in electrical energy usage.

  1. 2400MWt GAS-COOLED FAST REACTOR DHR STUDIES STATUS UPDATE.

    Energy Technology Data Exchange (ETDEWEB)

    CHENG,L.Y.; LUDEWIG, H.

    2007-06-01

    A topical report on demonstrating the efficacy of a proposed hybrid active/passive combination approach to the decay heat removal for an advanced 2400MWt GEN-IV gas-cooled fast reactor was published in March 2006. The analysis was performed with the system code RELAP5-3D (version 2.4.1.1a) and the model included the full complement of the power conversion unit (PCU): heat exchange components (recuperator, precooler, intercooler) and rotating machines (turbine, compressor). A re-analysis of the success case in Ref is presented in this report. The case was redone to correct unexpected changes in core heat structure temperatures when the PCU model was first integrated with the reactor model as documented in Ref [1]. Additional information on the modeling of the power conversion unit and the layout of the heat exchange components is provided in Appendix A.

  2. Advanced lightweight cooling-garment technology: functional improvements in thermosensitive patients with multiple sclerosis.

    Science.gov (United States)

    Meyer-Heim, A; Rothmaier, M; Weder, M; Kool, J; Schenk, P; Kesselring, J

    2007-03-01

    Cooling of thermosensitive patients with multiple sclerosis (MS) can improve clinical symptoms. In order to study the effectiveness of an advanced lightweight cooling-garment technology based on aquatic evaporation, a single-blinded balanced crossover study was performed on 20 patients with an Expanded Disability Status Scale score garment prototype for peripheral cooling suggest improvement of a timed-walking test, leg-strength, fine-motor skills and subjective benefits. Preliminary data of the heart rate variability (HRV) including six patients suggest that the MS patients show an abnormal HRV after sham condition, which is normalized after cooling. Technical information was gained about the cooling activity and the practicability and handling of the device. These encouraging findings promote further adaptations of the prototype to increase its cooling properties and ameliorate the practicability of the cooling garment.

  3. Advanced Liquid-Cooling Garment Using Highly Thermally Conductive Sheets

    Science.gov (United States)

    Ruemmele, Warren P.; Bue, Grant C.; Orndoff, Evelyne; Tang, Henry

    2010-01-01

    This design of the liquid-cooling garment for NASA spacesuits allows the suit to remove metabolic heat from the human body more effectively, thereby increasing comfort and performance while reducing system mass. The garment is also more flexible, with fewer restrictions on body motion, and more effectively transfers thermal energy from the crewmember s body to the external cooling unit. This improves the garment s performance in terms of the maximum environment temperature in which it can keep a crewmember comfortable. The garment uses flexible, highly thermally conductive sheet material (such as graphite), coupled with cooling water lines of improved thermal conductivity to transfer the thermal energy from the body to the liquid cooling lines more effectively. The conductive sheets can be layered differently, depending upon the heat loads, in order to provide flexibility, exceptional in-plane heat transfer, and good through-plane heat transfer. A metal foil, most likely aluminum, can be put between the graphite sheets and the external heat source/sink in order to both maximize through-plane heat transfer at the contact points, and to serve as a protection to the highly conductive sheets. Use of a wicking layer draws excess sweat away from the crewmember s skin and the use of an outer elastic fabric ensures good thermal contact of the highly conductive underlayers with the skin. This allows the current state of the art to be improved by having cooling lines that can be more widely spaced to improve suit flexibility and to reduce weight. Also, cooling liquid does not have to be as cold to achieve the same level of cooling. Specific areas on the human body can easily be targeted for greater or lesser cooling to match human physiology, a warmer external environment can be tolerated, and spatial uniformity of the cooling garment can be improved to reduce vasoconstriction limits. Elements of this innovation can be applied to other embodiments to provide effective heat

  4. Perancangan Turbine Inlet Cooling Untuk Meningkatkan Efisiensi Pembangkit Listrik Tenaga Gas Dengan Menggunakan Refrigerasi Absorpsi

    OpenAIRE

    Aditya, Ahmad

    2014-01-01

    Electrical energy plays an important role in the progress of a region, therefore the availability of electrical energy should be a priority. The availability of electricity can be achieved in two ways: the addition of new plants and improve the efficiency of existing plants. In this paper the task, the authors designed a compressor inlet air cooling system or TIC (turbine inlet cooling) on Gas Power Plant with a view to improving the efficiency of the engine. Cooling system ...

  5. Application of Gamma code coupled with turbomachinery models for high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh

    2008-02-01

    The very high-temperature gas-cooled reactor (VHTR) is envisioned as a single- or dual-purpose reactor for electricity and hydrogen generation. The concept has average coolant temperatures above 9000C and operational fuel temperatures above 12500C. The concept provides the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperature to support process heat applications, such as coal gasification, desalination or cogenerative processes, the VHTR’s higher temperatures allow broader applications, including thermochemical hydrogen production. However, the very high temperatures of this reactor concept can be detrimental to safety if a loss-ofcoolant accident (LOCA) occurs. Following the loss of coolant through the break and coolant depressurization, air will enter the core through the break by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heatup of the reactor core and the release of a toxic gas, CO, and fission products. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. Prior to the start of this Korean/United States collaboration, no computer codes were available that had been sufficiently developed and validated to reliably simulate a LOCA in the VHTR. Therefore, we have worked for the past three years on developing and validating advanced computational methods for simulating LOCAs in a VHTR. GAMMA code is being developed to implement turbomachinery models in the power conversion unit (PCU) and ultimately models associated with the hydrogen plant. Some preliminary results will be described in this paper.

  6. Advanced Materials for Mercury 50 Gas Turbine Combustion System

    Energy Technology Data Exchange (ETDEWEB)

    Price, Jeffrey

    2008-09-30

    Solar Turbines Incorporated (Solar), under cooperative agreement number DE-FC26-0CH11049, has conducted development activities to improve the durability of the Mercury 50 combustion system to 30,000 hours life and reduced life cycle costs. This project is part of Advanced Materials in the Advanced Industrial Gas Turbines program in DOE's Office of Distributed Energy. The targeted development engine was the Mercury{trademark} 50 gas turbine, which was developed by Solar under the DOE Advanced Turbine Systems program (DOE contract number DE-FC21-95MC31173). As a generator set, the Mercury 50 is used for distributed power and combined heat and power generation and is designed to achieve 38.5% electrical efficiency, reduced cost of electricity, and single digit emissions. The original program goal was 20,000 hours life, however, this goal was increased to be consistent with Solar's standard 30,000 hour time before overhaul for production engines. Through changes to the combustor design to incorporate effusion cooling in the Generation 3 Mercury 50 engine, which resulted in a drop in the combustor wall temperature, the current standard thermal barrier coated liner was predicted to have 18,000 hours life. With the addition of the advanced materials technology being evaluated under this program, the combustor life is predicted to be over 30,000 hours. The ultimate goal of the program was to demonstrate a fully integrated Mercury 50 combustion system, modified with advanced materials technologies, at a host site for a minimum of 4,000 hours. Solar was the Prime Contractor on the program team, which includes participation of other gas turbine manufacturers, various advanced material and coating suppliers, nationally recognized test laboratories, and multiple industrial end-user field demonstration sites. The program focused on a dual path development route to define an optimum mix of technologies for the Mercury 50 and future gas turbine products. For liner and

  7. Closed-cycle gas flow system for cooling of high Tc d.c. SQUID magnetometers

    NARCIS (Netherlands)

    Bosch, van den P.J.; Holland, H.J.; Brake, ter H.J.M.; Rogalla, H.

    1995-01-01

    A high Tc.d.c SQUID based magnetometer for magnetocardiography is currently under development at the University of Twente. Since such a magnetometer should be simple to use, the cooling of the system can be realized most practically by means of a cryocooler. A closed-cycle gas flow cooling system in

  8. SENSITIVE LIMITS ON THE MOLECULAR GAS CONTENT OF CLUSTER COOLING FLOWS

    NARCIS (Netherlands)

    MCNAMARA, BR; JAFFE, W

    1994-01-01

    We have searched for molecular gas toward six cluster cooling flows in the CO(2-1) line using the James Clerk Maxwell Telescope. The sample includes clusters with estimated total cooling rates Of m(CF) approximately 10-600M. yr-1, at redshifts between z approximately 0.01-0.06. None were detected ei

  9. Advanced Natural Gas Reciprocating Engine(s)

    Energy Technology Data Exchange (ETDEWEB)

    Pike, Edward

    2014-03-31

    The objective of the Cummins ARES program, in partnership with the US Department of Energy (DOE), is to develop advanced natural gas engine technologies that increase engine system efficiency at lower emissions levels while attaining lower cost of ownership. The goals of the project are to demonstrate engine system achieving 50% Brake Thermal Efficiency (BTE) in three phases, 44%, 47% and 50% (starting baseline efficiency at 36% BTE) and 0.1 g/bhp-hr NOx system out emissions (starting baseline NOx emissions at 2 – 4 g/bhp-hr NOx). Primary path towards above goals include high Brake Mean Effective Pressure (BMEP), improved closed cycle efficiency, increased air handling efficiency and optimized engine subsystems. Cummins has successfully demonstrated each of the phases of this program. All targets have been achieved through application of a combined set of advanced base engine technologies and Waste Heat Recovery from Charge Air and Exhaust streams, optimized and validated on the demonstration engine and other large engines. The following architectures were selected for each Phase: Phase 1: Lean Burn Spark Ignited (SI) Key Technologies: High Efficiency Turbocharging, Higher Efficiency Combustion System. In production on the 60/91L engines. Over 500MW of ARES Phase 1 technology has been sold. Phase 2: Lean Burn Technology with Exhaust Waste Heat Recovery (WHR) System Key Technologies: Advanced Ignition System, Combustion Improvement, Integrated Waste Heat Recovery System. Base engine technologies intended for production within 2 to 3 years Phase 3: Lean Burn Technology with Exhaust and Charge Air Waste Heat Recovery System Key Technologies: Lower Friction, New Cylinder Head Designs, Improved Integrated Waste Heat Recovery System. Intended for production within 5 to 6 years Cummins is committed to the launch of next generation of large advanced NG engines based on ARES technology to be commercialized worldwide.

  10. Indiana State University Graduates to Advanced Plastic Cooling Towers

    Science.gov (United States)

    Sullivan, Ed

    2012-01-01

    Perhaps more than many other industries, today's universities and colleges are beset by dramatically rising costs on every front. One of the areas where overhead can be contained or reduced is in the operation of the chilled water systems that support air conditioning throughout college campuses, specifically the cooling towers. Like many…

  11. Current design efforts for the gas-cooled fast reactor (GFR)

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, K.D. [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415-3850 (United States)]. e-mail: Kevan.Weaver@inl.gov

    2005-07-01

    Current research and development on the Gas-Cooled Fast Reactor (GCFR) has focused on the design of safety systems that will remove the decay heat during accident conditions, ion irradiations of candidate ceramic materials, joining studies of oxide dispersion strengthened alloys; and within the Advanced Fuel Cycle Initiative (AFC I) the fabrication of carbide fuels and ceramic fuel matrix materials, development of non-halide precursor low density and high density ceramic coatings, and neutron irradiation of candidate ceramic fuel matrix and metallic materials. The vast majority of this work has focused on the reference design for the GCFR: a helium-cooled, direct Brayton cycle power conversion system that will operate with an outlet temperature of 850 C at 7 MPa. In addition to the work being performed in the United States, seven international partners under the Generation IV International Forum (GIF) have identified their interest in participating in research related to the development of the GCFR. These are EURATOM (European Commission), France, Japan, South Africa, South Korea, Switzerland, and the United Kingdom. Of these, EURATOM (including the United Kingdom), France, Japan, and Switzerland have active research activities with respect to the GCFR. The research includes GCFR design and safety, and fuels/in-core materials/fuel cycle projects. This paper outlines the current design status of the GCFR, and includes work done in the areas mentioned above. (Author)

  12. Advanced Materials for Mercury 50 Gas Turbine Combustion System

    Energy Technology Data Exchange (ETDEWEB)

    Price, Jeffrey

    2008-09-30

    Solar Turbines Incorporated (Solar), under cooperative agreement number DE-FC26-0CH11049, has conducted development activities to improve the durability of the Mercury 50 combustion system to 30,000 hours life and reduced life cycle costs. This project is part of Advanced Materials in the Advanced Industrial Gas Turbines program in DOE's Office of Distributed Energy. The targeted development engine was the Mercury{trademark} 50 gas turbine, which was developed by Solar under the DOE Advanced Turbine Systems program (DOE contract number DE-FC21-95MC31173). As a generator set, the Mercury 50 is used for distributed power and combined heat and power generation and is designed to achieve 38.5% electrical efficiency, reduced cost of electricity, and single digit emissions. The original program goal was 20,000 hours life, however, this goal was increased to be consistent with Solar's standard 30,000 hour time before overhaul for production engines. Through changes to the combustor design to incorporate effusion cooling in the Generation 3 Mercury 50 engine, which resulted in a drop in the combustor wall temperature, the current standard thermal barrier coated liner was predicted to have 18,000 hours life. With the addition of the advanced materials technology being evaluated under this program, the combustor life is predicted to be over 30,000 hours. The ultimate goal of the program was to demonstrate a fully integrated Mercury 50 combustion system, modified with advanced materials technologies, at a host site for a minimum of 4,000 hours. Solar was the Prime Contractor on the program team, which includes participation of other gas turbine manufacturers, various advanced material and coating suppliers, nationally recognized test laboratories, and multiple industrial end-user field demonstration sites. The program focused on a dual path development route to define an optimum mix of technologies for the Mercury 50 and future gas turbine products. For liner and

  13. AGT 101 - Advanced Gas Turbine technology update

    Energy Technology Data Exchange (ETDEWEB)

    Kidwell, J.R.; Kreiner, D.M.

    1985-03-01

    The Advanced Gas Turbine (AGT) 101 program has made significant progress during 1984 in ceramic component and engine test bed development, including initial ceramic engine testing. All ceramic components for the AGT 101 (1644 K) engine are now undergoing development. Ceramic structures have been undergoing extensive analysis, design modification, and rig testing. AGT 101 (1644 K) start capability has been demonstrated in rig tests. Also, 1644 K steady-state testing has been initiated in the test rigs to obtain a better understanding of ceramics in that environment. The ceramic turbine rotor has progressed through cold spin test 12,040 rad/sec and hot turbine rig test, and is currently in initial phases of engine test. Over 400 hours of engine testing is expected by March 1985, including approximately 150 hours of operation and 50 starts on the 1422 K engine. All activities are progressing toward 1644 K engine testing in mid-1985.

  14. Cooling system having reduced mass pin fins for components in a gas turbine engine

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Marra, John J

    2014-03-11

    A cooling system having one or more pin fins with reduced mass for a gas turbine engine is disclosed. The cooling system may include one or more first surfaces defining at least a portion of the cooling system. The pin fin may extend from the surface defining the cooling system and may have a noncircular cross-section taken generally parallel to the surface and at least part of an outer surface of the cross-section forms at least a quartercircle. A downstream side of the pin fin may have a cavity to reduce mass, thereby creating a more efficient turbine airfoil.

  15. Ultra-low-temperature cooling of two-dimensional electron gas

    Science.gov (United States)

    Xia, J. S.; Adams, E. D.; Shvarts, V.; Pan, W.; Stormer, H. L.; Tsui, D. C.

    2000-05-01

    A new design has been used for cooling GaAs/Al xGa 1- xAs sample to ultra-low-temperatures. The sample, with electrical contacts directly soldered to the sintered silver powder heat exchangers, was immersed in liquid 3He, which was cooled by a PrNI 5 nuclear refrigerator. The data analysis shows that the two-dimensional electron gas (2DEG) was cooled to 4.0 mK at the refrigerator base temperature Tb of 2.0 mK. The design with heat exchanger cooling is applicable to any ultra-low-temperature transport measurements of 2DEG system.

  16. Prediction of Film Cooling on Gas Turbine Airfoils

    Science.gov (United States)

    Garg, Vijay K.; Gaugler, Raymond E.

    1994-01-01

    A three-dimensional Navier-Stokes analysis tool has been developed in order to study the effect of film cooling on the flow and heat transfer characteristics of actual turbine airfoils. An existing code (Arnone et al., 1991) has been modified for the purpose. The code is an explicit, multigrid, cell-centered, finite volume code with an algebraic turbulence model. Eigenvalue scaled artificial dissipation and variable-coefficient implicit residual smoothing are used with a full-multigrid technique. Moreover, Mayle's transition criterion (Mayle, 1991) is used. The effects of film cooling have been incorporated into the code in the form of appropriate boundary conditions at the hole locations on the airfoil surface. Each hole exit is represented by several control volumes, thus providing an ability to study the effect of hole shape on the film-cooling characteristics. Comparison is fair with near mid-span experimental data for four and nine rows of cooling holes, five on the shower head, and two rows each on the pressure and suction surfaces. The computations, however, show a strong spanwise variation of the heat transfer coefficient on the airfoil surface, specially with shower-head cooling.

  17. Performance analysis of a combined cycle gas turbine power plant by using various inlet air cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Rahim, Murad A. [Department of Mechanical Engineering, Gazi University (Turkey)], e-mail: mrahim@gazi.edu.tr

    2011-07-01

    In recent years, the use of gas turbines in combined cycle power plants has increased. Turbine inlet air cooling appears to be the best solution for maximizing both production and efficiency, particularly in a hot climate. The aim of this study is to determine the impact of different air cooling systems on the gas turbine's performance and carbon dioxide emissions. Computer simulations were carried out, using the THERMOFLEX program, on fogging, evaporative cooling, adsorption cooling, and electrical chiller cooling systems as well as on a base case without cooling system. Results showed that inlet air cooling systems are effective in increasing the efficiency of gas turbine power plants. In addition it was found that absorption chillers are the best system for increasing power generation but that economic and source analyses should be conducted before installing a cooling system. This paper demonstrated that inlet air cooling systems have the ability to increase net power generation of gas turbine power plants.

  18. Engineered Materials for Advanced Gas Turbine Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project will develop innovative composite powders and composites that will surpass the properties of currently identified materials for advanced gas turbine...

  19. Advanced adsorption cooling cum desalination cycle: A thermodynamic framework

    KAUST Repository

    Chakraborty, Anutosh

    2011-01-01

    We have developed a thermodynamic framework to calculate adsorption cooling cum desalination cycle performances as a function of pore widths and pore volumes of highly porous adsorbents, which are formulated from the rigor of thermodynamic property surfaces of adsorbent-adsorbate system and the adsorption interaction potential between them. Employing the proposed formulations, the coefficient of performance (COP) and overall performance ratio (OPR) of adsorption cycle are computed for various pore widths of solid adsorbents. These results are compared with experimental data for verifying the proposed thermodynamic formulations. It is found from the present analysis that the COP and OPR of adsorption cooling cum desalination cycle is influenced by (i) the physical characteristics of adsorbents, (ii) characteristics energy and (iii) the surface-structural heterogeneity factor of adsorbent-water system. The present study confirms that there exists a special type of adsorbents having optimal physical characteristics that allows us to obtain the best performance.

  20. Advanced turbine cooling, heat transfer, and aerodynamic studies

    Energy Technology Data Exchange (ETDEWEB)

    Je-Chin Han; Schobeiri, M.T. [Texas A& M Univ., College Station, TX (United States)

    1995-10-01

    The contractual work is in three parts: Part I - Effect of rotation on enhanced cooling passage heat transfer, Part II - Effect on Thermal Barrier Coating (TBC) spallation on surface heat transfer, and Part III - Effect of surface roughness and trailing edge ejection on turbine efficiency under unsteady flow conditions. Each section of this paper has been divided into three parts to individually accommodate each part. Part III is further divided into Parts IIIa and IIIb.

  1. Development of GAMMA Code and Evaluation for a Very High Temperature gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Chang H; Lim, H.S.; Kim, E.S.; NO, H.C.

    2007-06-01

    The very high-temperature gas-cooled reactor (VHTR) is envisioned as a single- or dual-purpose reactor for electricity and hydrogen generation. The concept has average coolant temperatures above 9000C and operational fuel temperatures above 12500C. The concept provides the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperature to support process heat applications, such as coal gasification, desalination or cogenerative processes, the VHTR’s higher temperatures allow broader applications, including thermochemical hydrogen production. However, the very high temperatures of this reactor concept can be detrimental to safety if a loss-of-coolant accident (LOCA) occurs. Following the loss of coolant through the break and coolant depressurization, air will enter the core through the break by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heatup of the reactor core and the release of toxic gasses (CO and CO2) and fission products. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. Prior to the start of this Korean/United States collaboration, no computer codes were available that had been sufficiently developed and validated to reliably simulate a LOCA in the VHTR. Therefore, we have worked for the past three years on developing and validating advanced computational methods for simulating LOCAs in a VHTR. This paper will also include what improvements will be made in the Gamma code for the VHTR.

  2. Fast Quasi-Adiabatic Gas Cooling: An Experiment Revisited

    Science.gov (United States)

    Oss, S.; Gratton, L. M.; Calza, G.; Lopez-Arias, T.

    2012-01-01

    The well-known experiment of the rapid expansion and cooling of the air contained in a bottle is performed with a rapidly responsive, yet very cheap thermometer. The adiabatic, low temperature limit is approached quite closely and measured with our apparatus. A straightforward theoretical model for this process is also presented and discussed.…

  3. The Accretion and Cooling of Preheated Gas in Dark Matter Halos

    CERN Document Server

    Lu, Y; Lu, Yu

    2006-01-01

    (abridged) We use a one-dimensional hydrodynamical code to investigate the effects of preheating on gas accretion and cooling in cold dark matter halos. In the absence of radiative cooling, preheating reduces the amount of gas that can be accreted into a halo, and the accreted gas fraction is determined by the ratio of the initial specific entropy of the gas to the virial entropy of the halo. In the presence of radiative cooling, preheating affects the gas fraction that can cool in two different ways. For small halos with masses 10^13Msun. We suggest that this may be the reason why the stellar mass function of galaxies breaks sharply at the massive end. Such preheating also helps create the hot diffused halos within which the "radio mode" feedback of AGNs can act effectively. In the second case, we assume the intergalactic medium is warm. Here the total amount of gas that can cool in a halo scales with halo mass as ~M^2, as would be required to match the observed stellar- and HI-mass functions in the current ...

  4. Advances in alkaline cooling water treatment technology: An update

    Energy Technology Data Exchange (ETDEWEB)

    Shaffer, A.E. Jr.; Klatskin, S.D.

    1985-01-01

    A series of chromate and non-chromate treatment programs, specifically designed for alkaline pH cooling waters, have been developed. The treatments provide excellent corrosion and scale control over a broad range of water chemistries and are applicable to high conductivity and iron contaminated waters. Low levels of zinc are used to reduce the dependency on alkalinity, chromate and calcium carbonate supersaturation for corrosion control. The precipitation and fouling problems previously encountered with zinc containing treatments have been eliminated by the use of polymeric dispersants.

  5. A combined gas cooled nuclear reactor and fuel cell cycle

    Science.gov (United States)

    Palmer, David J.

    Rising oil costs, global warming, national security concerns, economic concerns and escalating energy demands are forcing the engineering communities to explore methods to address these concerns. It is the intention of this thesis to offer a proposal for a novel design of a combined cycle, an advanced nuclear helium reactor/solid oxide fuel cell (SOFC) plant that will help to mitigate some of the above concerns. Moreover, the adoption of this proposal may help to reinvigorate the Nuclear Power industry while providing a practical method to foster the development of a hydrogen economy. Specifically, this thesis concentrates on the importance of the U.S. Nuclear Navy adopting this novel design for its nuclear electric vessels of the future with discussion on efficiency and thermodynamic performance characteristics related to the combined cycle. Thus, the goals and objectives are to develop an innovative combined cycle that provides a solution to the stated concerns and show that it provides superior performance. In order to show performance, it is necessary to develop a rigorous thermodynamic model and computer program to analyze the SOFC in relation with the overall cycle. A large increase in efficiency over the conventional pressurized water reactor cycle is realized. Both sides of the cycle achieve higher efficiencies at partial loads which is extremely important as most naval vessels operate at partial loads as well as the fact that traditional gas turbines operating alone have poor performance at reduced speeds. Furthermore, each side of the cycle provides important benefits to the other side. The high temperature exhaust from the overall exothermic reaction of the fuel cell provides heat for the reheater allowing for an overall increase in power on the nuclear side of the cycle. Likewise, the high temperature helium exiting the nuclear reactor provides a controllable method to stabilize the fuel cell at an optimal temperature band even during transients helping

  6. Design and Transient Analysis of Passive Safety Cooling Systems for Advanced Nuclear Reactors

    OpenAIRE

    Galvez, Cristhian

    2011-01-01

    The Pebble Bed Advanced High Temperature Reactor (PB-AHTR) is a pebble fueled, liquid salt cooled, high temperature nuclear reactor design that can be used for electricity generation or other applications requiring the availability of heat at elevated temperatures. A stage in the design evolution of this plant requires the analysis of the plant during a variety of potential transients to understand the primary and safety cooling system response. This study focuses on the performance of the pa...

  7. Model tests on cooling of gas turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Hosenfeld, H.G.; von Schwerdtner, O.A. (Kraftwerk Union A.G., Muelheim an der Ruhr (Germany, F.R.). Versuchswesen)

    1979-01-01

    The experimental handling of the blade cooling problems requires test facilities suited to each particular problem in order to obtain an independent variation of influence values. To carry out investigations with the high temperatures of the actual machine, however, would necessitate expenditure of time and money. Consideration of the Law of Similarity results in a reduction in temperature and pressure. A test arrangement is shown and typical results are explained by means of examples.

  8. Method of cooling gas only nozzle fuel tip

    Science.gov (United States)

    Bechtel, William Theodore; Fitts, David Orus; DeLeonardo, Guy Wayne

    2002-01-01

    A diffusion flame nozzle gas tip is provided to convert a dual fuel nozzle to a gas only nozzle. The nozle tip diverts compressor discharge air from the passage feeding the diffusion nozzle air swirl vanes to a region vacated by removal of the dual fuel components, so that the diverted compressor discharge air can flow to and through effusion holes in the end cap plate of the nozzle tip. In a preferred embodiment, the nozzle gas tip defines a cavity for receiving the compressor discharge air from a peripheral passage of the nozzle for flow through the effusion openings defined in the end cap plate.

  9. A review of gas-cooled reactor concepts for SDI (Strategic Defense Initiative) applications

    Energy Technology Data Exchange (ETDEWEB)

    Marshall, A.C.

    1989-08-01

    We have completed a review of multimegawatt gas-cooled reactor concepts proposed for SDI applications. Our study concluded that the principal reason for considering gas-cooled reactors for burst-mode operation was the potential for significant system mass savings over closed-cycle systems if open-cycle gas-cooled operation (effluent exhausted to space) is acceptable. The principal reason for considering gas-cooled reactors for steady-state operation is that they may represent a lower technology risk than other approaches. In the review, nine gas-cooled reactor concepts were compared to identify the most promising. For burst-mode operation, the NERVA (Nuclear Engine for Rocket Vehicle Application) derivative reactor concept emerged as a strong first choice since its performance exceeds the anticipated operational requirements and the technology has been demonstrated and is retrievable. Although the NERVA derivative concepts were determined to be the lead candidates for the Multimegawatt Steady-State (MMWSS) mode as well, their lead over the other candidates is not as great as for the burst mode. 90 refs., 2 figs., 10 tabs.

  10. Development and fabrication of an advanced liquid cooling garment

    Science.gov (United States)

    Hixon, C. W.

    1978-01-01

    A tube/fin concept liquid cooling garment head cooler was developed, fabricated and delivered to NASA-ARC. The head cooler was fabricated from polyurethane film which sandwiches the transport fluid tubing and a thermally conductive fin material. The head cooler garment is sewn to form a skull cap and covered with a comfort liner. In addition, two Neonate heating garments were fabricated and supplied to NASA for further finishing and use in medical tests. The resulting garment is flexible, elastic and conforms to the head comfortably. Tests on a tube/fin element of identical construction as the head cooler demonstrated good thermal effectiveness. Use of commercially available materials and development of relatively simple fabrication techniques give the potential for a low garment cost.

  11. Novel Applications of Buffer-Gas Cooling to Cold Atoms, Diatomic Molecules, and Large Molecules

    OpenAIRE

    Drayna, Garrett Korda

    2016-01-01

    Cold gases of atoms and molecules provide a system for the exploration of a diverse set of physical phenomena. For example, cold gasses of magnetically and electrically polar atoms and molecules are ideal systems for quantum simulation and quantum computation experiments, and cold gasses of large polar molecules allow for novel spectroscopic techniques. Buffer-gas cooling is a robust and widely applicable method for cooling atoms and molecules to temperatures of approximately 1 Kelvin. In thi...

  12. Interactions between radio sources and X-ray gas at the centers of cooling core clusters

    Science.gov (United States)

    Sarazin, C. L.; Blanton, E. L.; Clarke, T. E.

    Recent Chandra and XMM observations of the interaction of central radio sources and cooling cores in clusters of galaxies will be presented. The clusters studied include A262, A2052, A2626, A113, A2029, A2597, and A4059. The radio sources blow "bubbles" in the X-ray gas, displacing the gas and compressing it into shells around the radio lobes. At the same time, the radio sources are confined by the X-ray gas. At larger radii, "ghost bubbles" are seen which are weak in radio emission except at low frequencies. These may be evidence of previous eruptions of the radio sources. In some cases, buoyantly rising bubbles may entrain cooler X-ray gas from the centers of the cooling cores. Some radio sources previously classified as cluster merger radio relics may actually be displaced radio bubbles from the central radio sources. The relation between the radio bubbles, and cooler gas (10 keV).

  13. CFD Model Development and validation for High Temperature Gas Cooled Reactor Cavity Cooling System (RCCS) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Yassin [Univ. of Wisconsin, Madison, WI (United Texas A & M Univ., College Station, TX (United States); Corradini, Michael; Tokuhiro, Akira; Wei, Thomas Y.C.

    2014-07-14

    The Reactor Cavity Cooling Systems (RCCS) is a passive safety system that will be incorporated in the VTHR design. The system was designed to remove the heat from the reactor cavity and maintain the temperature of structures and concrete walls under desired limits during normal operation (steady-state) and accident scenarios. A small scale (1:23) water-cooled experimental facility was scaled, designed, and constructed in order to study the complex thermohydraulic phenomena taking place in the RCCS during steady-state and transient conditions. The facility represents a portion of the reactor vessel with nine stainless steel coolant risers and utilizes water as coolant. The facility was equipped with instrumentation to measure temperatures and flow rates and a general verification was completed during the shakedown. A model of the experimental facility was prepared using RELAP5-3D and simulations were performed to validate the scaling procedure. The experimental data produced during the steady-state run were compared with the simulation results obtained using RELAP5-3D. The overall behavior of the facility met the expectations. The facility capabilities were confirmed to be very promising in performing additional experimental tests, including flow visualization, and produce data for code validation.

  14. Cooling of Gas Turbines. 6; Computed Temperature Distribution Through Cross Section of Water-Cooled Turbine Blade

    Science.gov (United States)

    Livingood, John N. B.; Sams, Eldon W.

    1947-01-01

    A theoretical analysis of the cross-sectional temperature distribution of a water-cooled turbine blade was made using the relaxation method to solve the differential equation derived from the analysis. The analysis was applied to specific turbine blade and the studies icluded investigations of the accuracy of simple methods to determine the temperature distribution along the mean line of the rear part of the blade, of the possible effect of varying the perimetric distribution of the hot gas-to -metal heat transfer coefficient, and of the effect of changing the thermal conductivity of the blade metal for a constant cross sectional area blade with two quarter inch diameter coolant passages.

  15. Effect of Gas/Steam Turbine Inlet Temperatures on Combined Cycle Having Air Transpiration Cooled Gas Turbine

    Science.gov (United States)

    Kumar, S.; Singh, O.

    2012-10-01

    Worldwide efforts are being made for further improving the gas/steam combined cycle performance by having better blade cooling technology in topping cycle and enhanced heat recovery in bottoming cycle. The scope of improvement is possible through turbines having higher turbine inlet temperatures (TITs) of both gas turbine and steam turbine. Literature review shows that a combined cycle with transpiration cooled gas turbine has not been analyzed with varying gas/steam TITs. In view of above the present study has been undertaken for thermodynamic study of gas/steam combined cycle with respect to variation in TIT in both topping and bottoming cycles, for air transpiration cooled gas turbine. The performance of combined cycle with dual pressure heat recovery steam generator has been evaluated for different cycle pressure ratios (CPRs) varying from 11 to 23 and the selection diagrams presented for TIT varying from 1,600 to 1,900 K. Both the cycle efficiency and specific work increase with TIT for each pressure ratio. For each TIT there exists an optimum pressure ratio for cycle efficiency and specific work. For the CPR of 23 the best cycle performance is seen at a TIT of 1,900 K for maximum steam temperature of 570 °C, which gives the cycle efficiency of 60.9 % with net specific work of 909 kJ/kg.

  16. Advances in precision Doppler spectroscopy on cool stars

    Directory of Open Access Journals (Sweden)

    Anglada-Escudé Guillem

    2013-04-01

    Full Text Available I describe recent advances made in Doppler spectroscopy of low mass star and discuss how they perform on public observations ontained with the HARPS spectrograph. This work is possible thanks to the recent development of the HARPS-TERRA software (Template Enhanced Radial velocity Re-analysis Application, which obtains precision RV measurements by least-squares matching each spectrum to a high SNR template built from the same observations. As a result, we obtain a substantial increase in precision compared to the traditional cross-correlation methods. The increase in precision is demonstrated with RV measurements on stable M dwarfs (80 cm/s over time-scales of years and the early detection of several very low mass candidates. Moreover, the ability of HARPS-TERRA in reproducing the observed spectra at high fidelity allows us to explore new effects including : wavelength dependence of activity induced Doppler signals, simultaneous measurement of orbital obliquities and stellar rotation profiles and, when combined with advanced Bayesian data analysis techniques, small Doppler signals likely caused by new super-Earth mass candidates in the habitable zones of nearby stars.

  17. Thermoeconomic impact on combined cycle performance of advanced blade cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Ghigliazza, Francesco; Traverso, Alberto; Massardo, Aristide Fausto [Thermochemical Power Group (TPG), Dipartimento di Macchine, Sistemi Energetici e Trasporti (DIMSET) - University of Genoa (Italy)

    2009-10-15

    In this work the thermoeconomic features of two different combined cycles using air ''open loop'' and steam ''closed loop'' cooled gas turbines are presented and compared in depth. In order to properly estimate both thermodynamic and thermoeconomic performance of the different combined cycles an analytical model of the blade cooling system has been developed in details and outlined in the paper. Internal Thermoeconomic functional analysis is not performed here, as only economic results are shown and discussed. The blade cooling detailed model, originally developed by TPG researchers, has been integrated into the web based modular code WTEMP, already validated for GT based cycles, developed in the last ten years by TPG. It is shown that the closed loop blade cooling configuration has the greatest potential in terms of thermodynamic efficiency and economic competitivity in the mid-term. (author)

  18. Implementation of gas district cooling and cogeneration systems in Malaysia; Mise en oeuvre de systemes de gas district cooling et de cogeneration en Malaisie

    Energy Technology Data Exchange (ETDEWEB)

    Haron, S. [Gas District Cooling, M, Sdn Bhd (Malaysia)

    2000-07-01

    With its energy demand in the early 1990's growing at a high rate due to the country's strong economic growth, Malaysia studied various options to improve the efficiency of its energy use. Since its natural gas reserves are almost four times that of its crude oil reserves, efforts were therefore centered on seeking ways to boost the use of natural gas to mitigate the growing domestic energy need. PETRONAS, the national oil company, subsequently studied and chose the District Cooling System using natural gas as the primary source of fuel. The Kuala Lumpur City Center development, which houses the PETRONAS Twin Towers, was subsequently chosen as the first project to use the Gas District Cooling (GDC) System. To acquire the technology and implement this project, PETRONAS created a new subsidiary, Gas District Cooling (Malaysia) Sendirian Berhad (GDC(M)). In the process of improving the plant's efficiency, GDC(M) discovered that the GDC system's efficiency and project economics would be significantly enhanced if its is coupled to a Cogeneration system. Having proven the success of the GDC/Cogeneration system, GDC(M) embarked on a campaign to aggressively promote and seek new opportunities to implement the system, both in Malaysia-and abroad. Apart from enhancing efficiency of energy use, and providing better project economics, the GDC/Cogeneration system also is environment friendly. Today, the GDC/Cogeneration systems is the system of choice for several important developments in Malaysia, which also includes the country's prestigious projects such as the Kuala Lumpur International Airport and the New Federal Government Administrative Center in Putrajaya. (author)

  19. Development of gas cooled reactors and experimental setup of high temperature helium loop for in-pile operation

    Energy Technology Data Exchange (ETDEWEB)

    Miletić, Marija, E-mail: marija_miletic@live.com [Czech Technical University in Prague, Prague (Czech Republic); Fukač, Rostislav, E-mail: fuk@cvrez.cz [Research Centre Rez Ltd., Rez (Czech Republic); Pioro, Igor, E-mail: Igor.Pioro@uoit.ca [University of Ontario Institute of Technology, Oshawa (Canada); Dragunov, Alexey, E-mail: Alexey.Dragunov@uoit.ca [University of Ontario Institute of Technology, Oshawa (Canada)

    2014-09-15

    Highlights: • Gas as a coolant in Gen-IV reactors, history and development. • Main physical parameters comparison of gas coolants: carbon dioxide, helium, hydrogen with water. • Forced convection in turbulent pipe flow. • Gas cooled fast reactor concept comparisons to very high temperature reactor concept. • High temperature helium loop: concept, development, mechanism, design and constraints. - Abstract: Rapidly increasing energy and electricity demands, global concerns over the climate changes and strong dependence on foreign fossil fuel supplies are powerfully influencing greater use of nuclear power. In order to establish the viability of next-generation reactor concepts to meet tomorrow's needs for clean and reliable energy production the fundamental research and development issues need to be addressed for the Generation-IV nuclear-energy systems. Generation-IV reactor concepts are being developed to use more advanced materials, coolants and higher burn-ups fuels, while keeping a nuclear reactor safe and reliable. One of the six Generation-IV concepts is a very high temperature reactor (VHTR). The VHTR concept uses a graphite-moderated core with a once-through uranium fuel cycle, using high temperature helium as the coolant. Because helium is naturally inert and single-phase, the helium-cooled reactor can operate at much higher temperatures, leading to higher efficiency. Current VHTR concepts will use fuels such as uranium dioxide, uranium carbide, or uranium oxycarbide. Since some of these fuels are new in nuclear industry and due to their unknown properties and behavior within VHTR conditions it is very important to address these issues by investigate their characteristics within conditions close to those in VHTRs. This research can be performed in a research reactor with in-pile helium loop designed and constructed in Research Center Rez Ltd. One of the topics analyzed in this article are also physical characteristic and benefits of gas

  20. Summary of research and development effort on air and water cooling of gas turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Fraas, A.P.

    1980-03-01

    The review on air- and water-cooled gas turbines from the 1904 Lemale-Armengaud water-cooled gas turbine, the 1948 to 1952 NACA work, and the program at GE indicates that the potential of air cooling has been largely exploited in reaching temperatures of 1100/sup 0/C (approx. 2000/sup 0/F) in utility service and that further increases in turbine inlet temperature may be obtained with water cooling. The local heat flux in the first-stage turbine rotor with water cooling is very high, yielding high-temperature gradients and severe thermal stresses. Analyses and tests indicate that by employing a blade with an outer cladding of an approx. 1-mm-thick oxidation-resistant high-nickel alloy, a sublayer of a high-thermal-conductivity, high-strength, copper alloy containing closely spaced cooling passages approx. 2 mm in ID to minimize thermal gradients, and a central high-strength alloy structural spar, it appears possible to operate a water-cooled gas turbine with an inlet gas temperature of 1370/sup 0/C. The cooling-water passages must be lined with an iron-chrome-nickel alloy must be bent 90/sup 0/ to extend in a neatly spaced array through the platform at the base of the blade. The complex geometry of the blade design presents truly formidable fabrication problems. The water flow rate to each of many thousands of coolant passages must be metered and held to within rather close limits because the heat flux is so high that a local flow interruption of only a few seconds would lead to a serious failure.Heat losses to the cooling water will run approx. 10% of the heat from the fuel. By recoverying this waste heat for feedwater heating in a command cycle, these heat losses will give a degradation in the power plant output of approx. 5% relative to what might be obtained if no cooling were required. However, the associated power loss is less than half that to be expected with an elegant air cooling system.

  1. Efficiency of gas cooling and accretion at the disc-corona interface

    Science.gov (United States)

    Armillotta, L.; Fraternali, F.; Marinacci, F.

    2016-11-01

    In star-forming galaxies, stellar feedback can have a dual effect on the circumgalactic medium both suppressing and stimulating gas accretion. The trigger of gas accretion can be caused by disc material ejected into the halo in the form of fountain clouds and by its interaction with the surrounding hot corona. Indeed, at the disc-corona interface, the mixing between the cold/metal-rich disc gas (T ≲ 104 K) and the hot coronal gas (T ≳ 106 K) can dramatically reduce the cooling time of a portion of the corona and produce its condensation and accretion. We studied the interaction between fountain clouds and corona in different galactic environments through parsec-scale hydrodynamical simulations, including the presence of thermal conduction, a key mechanism that influences gas condensation. Our simulations showed that the coronal gas condensation strongly depends on the galactic environment, in particular it is less efficient for increasing virial temperature/mass of the haloes where galaxies reside and it is fully ineffective for objects with virial masses larger than 1013 M⊙. This result implies that the coronal gas cools down quickly in haloes with low-intermediate virial mass (Mvir ≲ 3 × 1012 M⊙) but the ability to cool the corona decreases going from late-type to early-type disc galaxies, potentially leading to the switching off of accretion and the quenching of star formation in massive systems.

  2. An Advanced Oscillation Mixing Method for Improving the Cooling Uniformity in Quenching

    Institute of Scientific and Technical Information of China (English)

    Hiroyuki Hoshino; Hiromitsu Murakami; Hideo Yokota; Satoshi Suda; Hideki Tsuge; Koichi Terasaka; Toshiaki Wakabayashi

    2004-01-01

    In quenching, the cooling uniformity is most important to diminish distortion occurring on work pieces. As a trial to accomplish uniform cooling, therefore, there exist various mixing methods of a quenchant and the quenchant circulation with an external pump has so far been the well accepted mixing method. However, this study proposes an advanced oscillation mixing method that can improve more the cooling uniformity in quenching. The proposed method includes a stirrer in oscillating motion, so that the simultaneous oscillating and mixing movements of the stirrer are considered to provide effectively the uniform cooling characteristics for the quenchant. In comparison with the case of the circulation pump mixing, the investigation using the oscillation mixing method has demonstrated the following two experimental facts:(1) the short vapor blanket stage caused by the quick breakage of the oil vapor blanket and (2) the reduced variation of the quenching distortion.

  3. Coupling of Modular High-Temperature Gas-Cooled Reactor with Supercritical Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Shutang Zhu

    2008-01-01

    Full Text Available This paper presents investigations on the possible combination of modular high-temperature gas-cooled reactor (MHTGR technology with the supercritical (SC steam turbine technology and the prospective deployments of the MHTGR SC power plant. Energy conversion efficiency of steam turbine cycle can be improved by increasing the main steam pressure and temperature. Investigations on SC water reactor (SCWR reveal that the development of SCWR power plants still needs further research and development. The MHTGR SC plant coupling the existing technologies of current MHTGR module design with operation experiences of SC FPP will achieve high cycle efficiency in addition to its inherent safety. The standard once-reheat SC steam turbine cycle and the once-reheat steam cycle with life-steam have been studied and corresponding parameters were computed. Efficiencies of thermodynamic processes of MHTGR SC plants were analyzed, while comparisons were made between an MHTGR SC plant and a designed advanced passive PWR - AP1000. It was shown that the net plant efficiency of an MHTGR SC plant can reach 45% or above, 30% higher than that of AP1000 (35% net efficiency. Furthermore, an MHTGR SC plant has higher environmental competitiveness without emission of greenhouse gases and other pollutants.

  4. Circulating and plateout activity program for gas-cooled reactors with arbitrary radioactive chains

    Energy Technology Data Exchange (ETDEWEB)

    Apperson, C.E. Jr.

    1978-03-01

    A time-dependent method for estimating the fuel body, circulating, plateout, and filter inventory of a high temperature gas-cooled reactor (HTGR) during normal operation is discussed. The primary coolant model accounts for the source, buildup, decay, and cleanup of isotopes that are gas borne inside the prestressed concrete reactor vessel (PCRV). This method has been implemented in the SUVIUS computer program that is described in detail.

  5. Thermoregulated Nitric Cryosystem for Cooling Gas-Filled Detectors of Ionizing Radiation

    Directory of Open Access Journals (Sweden)

    Zharkov I.P.

    2015-09-01

    Full Text Available Cryosystem for cooling and filling of gas-filled detectors of ionizing radiation with compressed inert gas on the basis of wide-nitrogen cryostat, which provides detetector temperature control in a range of 173 — 293 K and its stabilization with accuracy of ± 1°. The work was carried out within the Ukraine — NATO Program of Collaboration, Grant SfP #984655.

  6. Neutral gas sympathetic cooling of an ion in a Paul trap

    CERN Document Server

    Chen, Kuang; Hudson, Eric R

    2013-01-01

    A single ion immersed in a neutral buffer gas is studied. An analytical model is developed that gives a complete description of the dynamics and steady-state properties of the ions. An extension of this model, using techniques borrowed from the mathematics of finance, is used to explain the recent observation of non-Maxwellian statistics for these systems. Taken together, these results offer an explanation of the longstanding issues associated with sympathetic cooling of an ion by a neutral buffer gas.

  7. Cool core cycles: Cold gas and AGN jet feedback in cluster cores

    CERN Document Server

    Prasad, Deovrat; Babul, Arif

    2015-01-01

    Using high-resolution 3-D and 2-D (axisymmetric) hydrodynamic simulations in spherical geometry, we study the evolution of cool cluster cores heated by feedback-driven bipolar active galactic nuclei (AGN) jets. Condensation of cold gas, and the consequent enhanced accretion, is required for AGN feedback to balance radiative cooling with reasonable efficiencies, and to match the observed cool core properties. A feedback efficiency (mechanical luminosity $\\approx \\epsilon \\dot{M}_{\\rm acc} c^2$; where $\\dot{M}_{\\rm acc}$ is the mass accretion rate at 1 kpc) as small as $5 \\times 10^{-5}$ is sufficient to reduce the cooling/accretion rate by $\\sim 10$ compared to a pure cooling flow. This value is smaller compared to the ones considered earlier, and is consistent with the jet efficiency and the fact that only a small fraction of gas at 1 kpc is accreted on to the supermassive black hole (SMBH). We find hysteresis cycles in all our simulations with cold mode feedback: {\\em condensation} of cold gas when the ratio...

  8. A Techno-Economic Assessment of Hybrid Cooling Systems for Coal- and Natural-Gas-Fired Power Plants with and without Carbon Capture and Storage.

    Science.gov (United States)

    Zhai, Haibo; Rubin, Edward S

    2016-04-05

    Advanced cooling systems can be deployed to enhance the resilience of thermoelectric power generation systems. This study developed and applied a new power plant modeling option for a hybrid cooling system at coal- or natural-gas-fired power plants with and without amine-based carbon capture and storage (CCS) systems. The results of the plant-level analyses show that the performance and cost of hybrid cooling systems are affected by a range of environmental, technical, and economic parameters. In general, when hot periods last the entire summer, the wet unit of a hybrid cooling system needs to share about 30% of the total plant cooling load in order to minimize the overall system cost. CCS deployment can lead to a significant increase in the water use of hybrid cooling systems, depending on the level of CO2 capture. Compared to wet cooling systems, widespread applications of hybrid cooling systems can substantially reduce water use in the electric power sector with only a moderate increase in the plant-level cost of electricity generation.

  9. Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling

    Directory of Open Access Journals (Sweden)

    Matthias Hoeft

    2010-01-01

    Full Text Available Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40 kms−1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies.

  10. Advanced On Board Inert Gas Generation System (OBBIGS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Valcor Engineering Corporation proposes to develop an advanced On Board Inert Gas Generation System, OBIGGS, for aircraft fuel tank inerting to prevent hazardous...

  11. Engineering review of the core support structure of the Gas Cooled Fast Breeder Reactor

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-09-01

    The review of the core support structure of the gas cooled fast breeder reactor (GCFR) covered such areas as the design criteria, the design and analysis of the concepts, the development plan, and the projected manufacturing costs. Recommendations are provided to establish a basis for future work on the GCFR core support structure.

  12. Closed Fuel Cycle and Minor Actinide Multirecycling in a Gas-Cooled Fast Reactor

    NARCIS (Netherlands)

    Van Rooijen, W.F.G.; Kloosterman, J.L.

    2009-01-01

    The Generation IV International Forum has identified the Gas-Cooled Fast Reactor (GCFR) as one of the reactor concepts for future deployment. The GCFR targets sustainability, which is achieved by the use of a closed nuclear fuel cycle where only fission products are discharged to a repository; all H

  13. Gas-cooled fast reactor program. Progress report, January 1, 1980-June 30, 1981

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.

    1981-09-01

    Since the national Gas-Cooled Fast Breeder Reactor Program has been terminated, this document is the last progress report until reinstatement. It is divided into three sections: Core Flow Test Loop, GCFR shielding and physics, and GCFR pressure vessel and closure studies. (DLC)

  14. Migration of radionuclides in a gas cooled solid state spallation target

    DEFF Research Database (Denmark)

    Jørgensen, Thomas; Severin, Gregory; Jensen, Mikael

    2015-01-01

    The current design of the ESS (European Spallation Source) program proposes a rotating solid tungsten target cooled by helium gas and a pulsed beam of protons. For safety reasons any design has to address whether or not the induced radionuclidic isotopes in the target migrate. In this paper we ha...

  15. Materials and structural aspects of advanced gas-turbine helicopter engines

    Science.gov (United States)

    Freche, J. C.; Acurio, J.

    1979-01-01

    The key to improved helicopter gas turbine engine performance lies in the development of advanced materials and advanced structural and design concepts. The modification of the low temperature components of helicopter engines (such as the inlet particle separator), the introduction of composites for use in the engine front frame, the development of advanced materials with increased use-temperature capability for the engine hot section, can result in improved performance and/or decreased engine maintenance cost. A major emphasis in helicopter engine design is the ability to design to meet a required lifetime. This, in turn, requires that the interrelated aspects of higher operating temperatures and pressures, cooling concepts, and environmental protection schemes be integrated into component design. The major material advances, coatings, and design life-prediction techniques pertinent to helicopter engines are reviewed; the current state-of-the-art is identified; and when appropriate, progress, problems, and future directions are assessed.

  16. Comparative Exergoeconomic Analyses of Gas Turbine Steam Injection Cycles with and without Fogging Inlet Cooling

    Directory of Open Access Journals (Sweden)

    Hassan Athari

    2015-09-01

    Full Text Available The results are reported of exergoeconomic analyses of a simple gas turbine cycle without a fogging system (SGT, a simple steam injection gas turbine cycle (STIG, and a steam injection gas turbine cycle with inlet fogging cooler (FSTIG. The results show that (1 a gas-turbine cycle with steam injection and simultaneous cooling has a higher power output than the other considered cycle; (2 at maximum energy efficiency conditions the gas turbine has the highest exergy efficiency of the cycle components and the lowest value of exergy efficiency is calculated for the fog cooler, where the mixing of air and water at greatly different temperatures causes the high exergy destruction; and (3 utilization of the fogging cooler in the steam injection cycle increases the exergy destruction in the combustion chamber. Furthermore, the simple gas turbine cycle is found to be more economic as its relative cost difference, total unit product cost, and exergoeconomic factors are less than those for the two other configurations. However, its efficiency and net power output are notably lower than for the gas turbine with steam injection and/or fog cooling. The total unit product cost is highest for the simple gas turbine with steam injection.

  17. WASP-80b: a gas giant transiting a cool dwarf

    CERN Document Server

    Triaud, Amaury H M J; Cameron, A Collier; Doyle, A P; Fumel, A; Gillon, M; Hellier, C; Jehin, E; Lendl, M; Lovis, C; Maxted, P F L; Pepe, F; Pollacco, D; Queloz, D; Segransan, D; Smalley, B; Smith, A M S; Udry, S; West, R G; Wheatley, P J; 10.1051/0004-6361/201220900

    2013-01-01

    We report the discovery of a planet transiting the star WASP-80 (1SWASP J201240.26-020838.2; 2MASS J20124017-0208391; TYC 5165-481-1; BPM 80815; V=11.9, K=8.4). Our analysis shows this is a 0.55 +/- 0.04 Mjup, 0.95 +/- 0.03 Rjup gas giant on a circular 3.07 day orbit around a star with a spectral type between K7V and M0V. This system produces one of the largest transit depths so far reported, making it a worthwhile target for transmission spectroscopy. We find a large discrepancy between the v sin i inferred from stellar line broadening and the observed amplitude of the Rossiter-McLaughlin effect. This can be understood either by an orbital plane nearly perpendicular to the stellar spin or by an additional, unaccounted for source of broadening.

  18. How to get cool in the heat: comparing analytic models of hot, cold, and cooling gas in haloes and galaxies with EAGLE

    Science.gov (United States)

    Stevens, Adam R. H.; del P. Lagos, Claudia; Contreras, Sergio; Croton, Darren J.; Padilla, Nelson D.; Schaller, Matthieu; Schaye, Joop; Theuns, Tom

    2017-01-01

    We use the hydrodynamic, cosmological EAGLE simulations to investigate how hot gas in haloes condenses to form and grow galaxies. We select haloes from the simulations that are actively cooling and study the temperature, distribution, and metallicity of their hot, cold, and transitioning `cooling' gas, placing these in context of semi-analytic models. Our selection criteria lead us to focus on Milky Way-like haloes. We find the hot-gas density profiles of the haloes form a progressively stronger core over time, the nature of which can be captured by a β profile that has a simple dependence on redshift. In contrast, the hot gas that will cool over a time-step is broadly consistent with a singular isothermal sphere. We find that cooling gas carries a few times the specific angular momentum of the halo and is offset in spin direction from the rest of the hot gas. The gas loses ˜60% of its specific angular momentum during the cooling process, generally remaining greater than that of the halo, and it precesses to become aligned with the cold gas already in the disc. We find tentative evidence that angular-momentum losses are slightly larger when gas cools onto dispersion-supported galaxies. We show that an exponential surface density profile for gas arriving on a disc remains a reasonable approximation, but a cusp containing ˜20% of the mass is always present, and disc scale radii are larger than predicted by a vanilla Fall & Efstathiou model. These scale radii are still closely correlated with the halo spin parameter, for which we suggest an updated prescription for galaxy formation models.

  19. High Temperature Gas-cooled Reactor Projected Markets and Scoping Economics

    Energy Technology Data Exchange (ETDEWEB)

    Larry Demick

    2010-08-01

    The NGNP Project has the objective of developing the high temperature gas-cooled reactor (HTGR) technology to supply high temperature process heat to industrial processes as a substitute for burning of fossil fuels, such as natural gas. Applications of the HTGR technology that have been evaluated by the NGNP Project for supply of process heat include supply of electricity, steam and high-temperature gas to a wide range of industrial processes, and production of hydrogen and oxygen for use in petrochemical, refining, coal to liquid fuels, chemical, and fertilizer plants.

  20. THE DIRECT DETECTION OF COOL, METAL-ENRICHED GAS ACCRETION ONTO GALAXIES AT z {approx} 0.5

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, Kate H. R.; Xavier Prochaska, J. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, 69117 Heidelberg (Germany); Koo, David C. [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High St, Santa Cruz, CA 95064 (United States); Phillips, Andrew C., E-mail: rubin@mpia.de [UCO/Lick Observatory, University of California, 1156 High St, Santa Cruz, CA 95064 (United States)

    2012-03-10

    We report on the discovery of cool gas inflow toward six star-forming galaxies with redshifts z {approx} 0.35-1. Analysis of Mg II and Fe II resonance-line absorption in Keck/LRIS spectroscopy of the galaxies reveals positive velocity shifts for cool gas of 80-200 km s{sup -1} with respect to the host galaxy velocity centroids, and equivalent widths for this inflow of {approx}> 0.6 A in five of the six objects. The host galaxies exhibit a wide range of star formation rates (SFRs {approx}1-40 M{sub Sun} yr{sup -1}) and have stellar masses similar to that of the Milky Way (log M{sub *}/M{sub Sun} {approx} 9.6-10.5). Imaging from the Hubble Space Telescope Advanced Camera for Surveys indicates that five of the six galaxies have highly inclined (i > 55 Degree-Sign ), disk-like morphologies. These data represent the first unambiguous detection of inflow into isolated, star-forming galaxies in the distant universe. We suggest that the inflow is due to the infall of enriched material from dwarf satellites and/or a galactic fountain within the galaxies. Assuming that the material has been enriched to 0.1 Z{sub Sun} and has a physical extent approximately equal to that of the galaxies (implied by the high observed gas covering fractions), we infer mass inflow rates of dM{sub in}/dt {approx}> 0.2-3 M{sub Sun} yr{sup -1} for four of these systems. Finally, from comparison of these absorption lines to the profiles of Mg II and Fe II absorption in a larger spectroscopic sample of {approx}100 objects, we measure a covering fraction of cool inflow of at least 6%, but cannot rule out the presence of enriched infall onto as many as {approx}40 of these galaxies.

  1. WASP-80b: a gas giant transiting a cool dwarf

    Science.gov (United States)

    Triaud, A. H. M. J.; Anderson, D. R.; Collier Cameron, A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Hellier, C.; Jehin, E.; Lendl, M.; Lovis, C.; Maxted, P. F. L.; Pepe, F.; Pollacco, D.; Queloz, D.; Ségransan, D.; Smalley, B.; Smith, A. M. S.; Udry, S.; West, R. G.; Wheatley, P. J.

    2013-03-01

    We report the discovery of a planet transiting the star WASP-80 (1SWASP J201240.26-020838.2; 2MASS J20124017-0208391; TYC 5165-481-1; BPM 80815; V = 11.9, K = 8.4). Our analysis shows this is a 0.55 ± 0.04 Mjup, 0.95 ± 0.03 Rjup gas giant on a circular 3.07 day orbit around a star with a spectral type between K7V and M0V. This system produces one of the largest transit depths so far reported, making it a worthwhile target for transmission spectroscopy. We find a large discrepancy between the vsini⋆ inferred from stellar line broadening and the observed amplitude of the Rossiter-McLaughlin effect. This can be understood either by an orbital plane nearly perpendicular to the stellar spin or by an additional, unaccounted for source of broadening. Using WASP-South photometric observations, from Sutherland (South Africa), confirmed with the 60 cm TRAPPIST robotic telescope, EulerCam, and the CORALIE spectrograph on the Swiss 1.2 m Euler Telescope, and HARPS on the ESO 3.6 m (Prog ID 089.C-0151), all three located at La Silla Observatory, Chile.Radial velocity and photometric data are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A80

  2. Thermal Hydraulics of the Very High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Eung Kim; Richard Schultz; Mike Patterson; Davie Petti

    2009-10-01

    The U.S Department of Energy (DOE) is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R&D) that will be critical to the success of the NGNP, primarily in the areas of: • High temperature gas reactor fuels behavior • High temperature materials qualification • Design methods development and validation • Hydrogen production technologies • Energy conversion. This paper presents current R&D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs.

  3. Cesium Gas Strongly Confined In One Dimension Sideband Cooling And Collisional Properties

    CERN Document Server

    Bouchoule, I; Petrov, D S; Salomon, C

    2002-01-01

    We study one-dimensional sideband cooling of Cesium atoms strongly confined in a far-detuned optical lattice. The Lamb-Dicke regime is achieved in the lattice direction whereas the transverse confinement is much weaker. The employed sideband cooling method, first studied by Vuletic et al.\\cite{Vule98}, uses Raman transitions between Zeeman levels and produces a spin-polarized sample. We present a detailed study of this cooling method and investigate the role of elastic collisions in the system. We accumulate $83(5)%$ of the atoms in the vibrational ground state of the strongly confined motion, and elastic collisions cool the transverse motion to a temperature of $2.8 \\mu $K=$0.7 \\hbar\\omega_{\\rm osc}/k_{\\rm B}$, where $\\omega_{\\rm osc}$ is the oscillation frequency in the strongly confined direction. The sample then approaches the regime of a quasi-2D cold gas. We analyze the limits of this cooling method and propose a dynamical change of the trapping potential as a mean of cooling the atomic sample to still ...

  4. On the connection between radio mini-halos and gas heating in cool core clusters

    CERN Document Server

    Bravi, Luca; Brunetti, Gianfranco

    2016-01-01

    In this work, we present a study of the central regions of cool-core clusters hosting radio mini-halos, which are di use synchrotron sources extended on cluster-scales surrounding the radio-loud brightest galaxy. We aim to investigate the interplay between the thermal and non-thermal components in the intracluster medium in order to get more insights into these radio sources, whose nature is still unclear. It has recently been proposed that turbulence plays a role for heating the gas in cool cores. A correlation between the radio luminosity of mini-halos, $\

  5. Advances in light-gas gun technology

    Science.gov (United States)

    Cowan, P. L.; Murphy, J. R.

    1968-01-01

    Constant-area accelerator used with light-gas guns increases the velocity of accelerating projectiles. A disposable accelerator on the muzzle of the gun uses the energy and momentum of a primary projectile, launched by the gun, to achieve high velocities of a light secondary projectile accelerated from rest in the accelerator.

  6. Advanced Gas Storage Concepts: Technologies for the Future

    Energy Technology Data Exchange (ETDEWEB)

    Freeway, Katy (PB-KBB Inc.); Rogers, R.E. (Mississippi State University); DeVries, Kerry L.; Nieland, Joel D.; Ratigan, Joe L.; Mellegard, Kirby D. (RESPEC)

    2000-02-01

    This full text product includes: 1) A final technical report titled Advanced Underground Gas Storage Concepts, Refrigerated-Mined Cavern Storage and presentations from two technology transfer workshops held in 1998 in Houston, Texas, and Pittsburgh, Pennsylvania (both on the topic of Chilled Gas Storage in Mined Caverns); 2) A final technical report titled Natural Gas Hydrates Storage Project, Final Report 1 October 1997 - 31 May 1999; 3) A final technical report titled Natural Gas Hydrates Storage Project Phase II: Conceptual Design and Economic Study, Final Report 9 June - 10 October 1999; 4) A final technical report titled Commerical Potential of Natural Gas Storage in Lined Rock Caverns (LRC) and presentations from a DOE-sponsored workshop on Alternative Gas Storage Technologies, held Feb 17, 2000 in Pittsburgh, PA; and 5) Phase I and Phase II topical reports titled Feasibility Study for Lowering the Minimum Gas Pressure in Solution-Mined Caverns Based on Geomechanical Analyses of Creep-Induced Damage and Healing.

  7. Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

    2008-04-01

    A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: • Identifies pre-conceptual design requirements • Develops test loop equipment schematics and layout • Identifies space allocations for each of the facility functions, as required • Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems • Identifies pre-conceptual utility and support system needs • Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs.

  8. Spitzer Secondary Eclipse Observations of Five Cool Gas Giant Planets and Empirical Trends in Cool Planet Emission Spectra

    CERN Document Server

    Kammer, Joshua A; Line, Michael R; Fortney, Jonathan J; Deming, Drake; Burrows, Adam; Cowan, Nicolas B; Triaud, Amaury H M J; Agol, Eric; Desert, Jean-Michel; Fulton, Benjamin J; Howard, Andrew W; Laughlin, Gregory P; Lewis, Nikole K; Morley, Caroline V; Moses, Julianne I; Showman, Adam P; Todorov, Kamen O

    2015-01-01

    In this work we present Spitzer 3.6 and 4.5 micron secondary eclipse observations of five new cool (<1200 K) transiting gas giant planets: HAT-P-19b, WASP-6b, WASP-10b, WASP-39b, and WASP-67b. We compare our measured eclipse depths to the predictions of a suite of atmosphere models and to eclipse depths for planets with previously published observations in order to constrain the temperature- and mass-dependent properties of gas giant planet atmospheres. We find that the dayside emission spectra of planets less massive than Jupiter require models with efficient circulation of energy to the night side and/or increased albedos, while those with masses greater than that of Jupiter are consistently best-matched by models with inefficient circulation and low albedos. At these relatively low temperatures we expect the atmospheric methane to CO ratio to vary as a function of metallicity, and we therefore use our observations of these planets to constrain their atmospheric metallicities. We find that the most massi...

  9. Penetrating Gas Streams Generate Unrelaxed,Non-Cool-Core Clusters of Galaxies

    CERN Document Server

    Zinger, E; Birnboim, Y; Kravtsov, A; Nagai, D

    2015-01-01

    We utilize cosmological simulations of 16 galaxy clusters at redshifts $z=0$ and $z=0.6$ to study the effect of inflowing streams on the properties of the inner Intra-Cluster Medium (ICM). We find that the mass accretion occurs predominantly along streams that originate from the cosmic web and consist of heated gas. Clusters that are unrelaxed in terms of their X-ray morphology are characterized by higher mass inflow rates and deeper penetration of the streams, typically into the inner third of the virial radius. The penetrating streams generate elevated random motions, bulk flows, cold fronts and metal mixing, thus producing Non-Cool-Core clusters. The degree of penetration of the streams may change over time such that clusters can switch from being unrelaxed to relaxed over a time-scale of several Gyrs. The stream properties thus help us understand the distinction between cool-core and non-cool-core clusters.

  10. Flow structure and heat exchange analysis in internal cooling channel of gas turbine blade

    Science.gov (United States)

    Szwaba, Ryszard; Kaczynski, Piotr; Doerffer, Piotr; Telega, Janusz

    2016-08-01

    This paper presents the study of the flow structure and heat transfer, and also their correlations on the four walls of a radial cooling passage model of a gas turbine blade. The investigations focus on heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of radial cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include corner fillet, ribs with fillet radii and special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which possesses very realistic features.

  11. Advanced Technologies For Stripper Gas Well Enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Ronald J. MacDonald; Charles M. Boyer; Joseph H. Frantz Jr; Paul A. Zyglowicz

    2005-04-01

    Stripper gas and oil well operators frequently face a dilemma regarding maximizing production from low-productivity wells. With thousands of stripper wells in the United States covering extensive acreage, it is difficult to identify easily and efficiently marginal or underperforming wells. In addition, the magnitude of reviewing vast amounts of data places a strain on an operator's work force and financial resources. Schlumberger DCS, in cooperation with the National Energy Technology Laboratory (NETL) and the U.S. Department of Energy (DOE), has created software and developed in-house analysis methods to identify remediation potential in stripper wells relatively easily. This software is referred to as Stripper Well Analysis Remediation Methodology (SWARM). SWARM was beta-tested with data pertaining to two gas fields located in northwestern Pennsylvania and had notable results. Great Lakes Energy Partners, LLC (Great Lakes) and Belden & Blake Corporation (B&B) both operate wells in the first field studied. They provided data for 729 wells, and we estimated that 41 wells were candidates for remediation. However, for reasons unbeknownst to Schlumberger these wells were not budgeted for rework by the operators. The second field (Cooperstown) is located in Crawford, Venango, and Warren counties, Pa and has more than 2,200 wells operated by Great Lakes. This paper discusses in depth the successful results of a candidate recognition study of this area. We compared each well's historical production with that of its offsets and identified 339 underperformers before considering remediation costs, and 168 economically viable candidates based on restimulation costs of $50,000 per well. From this data, we prioritized a list based on the expected incremental recoverable gas and 10% discounted net present value (NPV). For this study, we calculated the incremental gas by subtracting the volumes forecasted after remediation from the production projected at its current

  12. Galaxies Probing Galaxies: Cool Halo Gas from a z = 0.47 Post-Starburst Galaxy

    Science.gov (United States)

    Rubin, Kate H. R.; Prochaska, J. Xavier; Koo, David C.; Phillips, Andrew C.; Weiner, Benjamin J.

    2010-03-01

    We study the cool gas around a galaxy at z = 0.4729 using Keck/LRIS spectroscopy of a bright (B = 21.7) background galaxy at z = 0.6942 at a transverse distance of 16.5h -1 70 kpc. The background galaxy spectrum reveals strong Fe II, Mg II, Mg I, and Ca II absorption at the redshift of the foreground galaxy, with an Mg II λ2796 rest equivalent width of 3.93 ± 0.08 Å, indicative of a velocity width exceeding 400 km s-1. Because the background galaxy is large (>4h -1 70 kpc), the high covering fraction of the absorbing gas suggests that it arises in a spatially extended complex of cool clouds with large velocity dispersion. Spectroscopy of the massive (log M */M sun = 11.15 ± 0.08) host galaxy reveals that it experienced a burst of star formation about 1 Gyr ago and that it harbors a weak active galactic nucleus. We discuss the possible origins of the cool gas in its halo, including multiphase cooling of hot halo gas, cold inflow, tidal interactions, and galactic winds. We conclude that the absorbing gas was most likely ejected or tidally stripped from the interstellar medium of the host galaxy or its progenitors during the past starburst event. Adopting the latter interpretation, these results place one of only a few constraints on the radial extent of cool gas driven or stripped from a galaxy in the distant universe. Future studies with integral field unit spectroscopy of spatially extended background galaxies will provide multiple sight lines through foreground absorbers and permit analysis of the morphology and kinematics of the gas surrounding galaxies with a diverse set of properties and environments. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  13. Comb-assisted cavity ring-down spectroscopy of a buffer-gas-cooled molecular beam.

    Science.gov (United States)

    Santamaria, Luigi; Sarno, Valentina Di; Natale, Paolo De; Rosa, Maurizio De; Inguscio, Massimo; Mosca, Simona; Ricciardi, Iolanda; Calonico, Davide; Levi, Filippo; Maddaloni, Pasquale

    2016-06-22

    We demonstrate continuous-wave cavity ring-down spectroscopy of a partially hydrodynamic molecular beam emerging from a buffer-gas-cooling source. Specifically, the (ν1 + ν3) vibrational overtone band of acetylene (C2H2) around 1.5 μm is accessed using a narrow-linewidth diode laser stabilized against a GPS-disciplined rubidium clock via an optical frequency comb synthesizer. As an example, the absolute frequency of the R(1) component is measured with a fractional accuracy of ∼1 × 10(-9). Our approach represents the first step towards the extension of more sophisticated cavity-enhanced interrogation schemes, including saturated absorption cavity ring-down or two-photon excitation, to buffer-gas-cooled molecular beams.

  14. High Temperature Gas-Cooled Test Reactor Point Design: Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bayless, Paul David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nelson, Lee Orville [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-01-01

    A point design has been developed for a 200-MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched uranium oxycarbide fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technology readiness level, licensing approach, and costs of the test reactor point design.

  15. High Temperature Gas-Cooled Test Reactor Point Design: Summary Report

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James William [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bayless, Paul David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nelson, Lee Orville [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gougar, Hans David [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinsey, J. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Strydom, Gerhard [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-03-01

    A point design has been developed for a 200-MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched uranium oxycarbide fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technology readiness level, licensing approach, and costs of the test reactor point design.

  16. A modular gas-cooled cermet reactor system for planetary base power

    Science.gov (United States)

    Jahshan, Salim N.; Borkowski, Jeffrey A.

    1993-01-01

    Fission nuclear power is foreseen as the source for electricity in planetary colonization and exploration. A six module gas-cooled, cermet-fueled reactor is proposed that can meet the design objectives. The highly enriched core is compact and can operate at high temperature for a long life. The helium coolant powers six modular Brayton cycles that compare favorably with the SP-100-based Brayton cycle.

  17. Application of gas-cooled Accelerator Driven System (ADS) transmutation devices to sustainable nuclear energy development

    OpenAIRE

    2011-01-01

    The conceptual design of a pebble bed gas-cooled transmutation device is shown with the aim to evaluate its potential for its deployment in the context of the sustainable nuclear energy development, which considers high temperature reactors for their operation in cogeneration mode, producing electricity, heat and Hydrogen. As differential characteristics our device operates in subcritical mode, driven by a neutron source activated by an accelerator that adds clear safety advantages and fuel f...

  18. Evaluation of proposed German safety criteria for high-temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Barsell, A.W.

    1980-05-01

    This work reviews proposed safety criteria prepared by the German Bundesministerium des Innern (BMI) for future licensing of gas-cooled high-temperature reactor (HTR) concepts in the Federal Republic of Germany. Comparison is made with US General Design Criteria (GDCs) in 10CFR50 Appendix A and with German light water reactor (LWR) criteria. Implications for the HTR design relative to the US design and safety approach are indicated. Both inherent characteristics and design features of the steam cycle, gas turbine, and process heat concepts are taken into account as well as generic design options such as a pebble bed or prismatic core.

  19. Alternative Liquid Fuel Effects on Cooled Silicon Nitride Marine Gas Turbine Airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Holowczak, J.

    2002-03-01

    With prior support from the Office of Naval Research, DARPA, and U.S. Department of Energy, United Technologies is developing and engine environment testing what we believe to be the first internally cooled silicon nitride ceramic turbine vane in the United States. The vanes are being developed for the FT8, an aeroderivative stationary/marine gas turbine. The current effort resulted in further manufacturing and development and prototyping by two U.S. based gas turbine grade silicon nitride component manufacturers, preliminary development of both alumina, and YTRIA based environmental barrier coatings (EBC's) and testing or ceramic vanes with an EBC coating.

  20. Neutral gas sympathetic cooling of an ion in a Paul trap.

    Science.gov (United States)

    Chen, Kuang; Sullivan, Scott T; Hudson, Eric R

    2014-04-11

    A single ion immersed in a neutral buffer gas is studied. An analytical model is developed that gives a complete description of the dynamics and steady-state properties of the ions. An extension of this model, using techniques employed in the mathematics of economics and finance, is used to explain the recent observation of non-Maxwellian statistics for these systems. Taken together, these results offer an explanation of the long-standing issues associated with sympathetic cooling of an ion by a neutral buffer gas.

  1. Irrigation Induced Surface Cooling in the Context of Modern and Increased Greenhouse Gas Forcing

    Science.gov (United States)

    Cook, Benjamin I.; Puma, Michael J.; Krakauer, Nir Y.

    2010-01-01

    There is evidence that expected warming trends from increased greenhouse gas (GHG) forcing have been locally masked by irrigation induced cooling, and it is uncertain how the magnitude of this irrigation masking effect will change in the future. Using an irrigation dataset integrated into a global general circulation model, we investigate the equilibrium magnitude of irrigation induced cooling under modern (Year 2000) and increased (A1B Scenario, Year 2050) GHG forcing, using modern irrigation rates in both scenarios. For the modern scenario, the cooling is largest over North America, India, the Middle East, and East Asia. Under increased GHG forcing, this cooling effect largely disappears over North America, remains relatively unchanged over India, and intensifies over parts of China and the Middle East. For North America, irrigation significantly increases precipitation under modern GHG forcing; this precipitation enhancement largely disappears under A1B forcing, reducing total latent heat fluxes and the overall irrigation cooling effect. Over India, irrigation rates are high enough to keep pace with increased evaporative demand from the increased GHG forcing and the magnitude of the cooling is maintained. Over China, GHG forcing reduces precipitation and shifts the region to a drier evaporative regime, leading to a relatively increased impact of additional water from irrigation on the surface energy balance. Irrigation enhances precipitation in the Middle East under increased GHG forcing, increasing total latent heat fluxes and enhancing the irrigation cooling effect. Ultimately, the extent to which irrigation will continue to compensate for the warming from increased GHG forcing will primarily depend on changes in the background evaporative regime, secondary irrigation effects (e.g. clouds, precipitation), and the ability of societies to maintain (or increase) current irrigation rates.

  2. Validation of SCALE and the TRITON Depletion Sequence for Gas-Cooled Reactor Analysis

    Energy Technology Data Exchange (ETDEWEB)

    DeHart, Mark D [ORNL; Pritchard, Megan L [ORNL

    2008-01-01

    The very-high-temperature reactor (VHTR) is an advanced reactor concept that uses graphite-moderated fuel and helium gas as a coolant. At present there are two primary VHTR reactor designs under consideration for development: in the pebble-bed reactor, a core is loaded with 'pebbles' consisting of 6 cm diameter spheres, while in a high-temperature gas-cooled reactor, fuel rods are placed within prismatic graphite blocks. In both systems, fuel elements (spheres or rods) are comprised of tristructural-isotropic (TRISO) fuel particles. The TRISO particles are either dispersed in the matrix of a graphite pebble for the pebble-bed design or molded into compacts/rods that are then inserted into the hexagonal graphite blocks for the prismatic concept. Two levels of heterogeneity exist in such fuel designs: (1) microspheres of TRISO particles dispersed in a graphite matrix of a cylindrical or spherical shape, and (2) neutron interactions at the rod-to-rod or sphere-to-sphere level. Such double heterogeneity (DH) provides a challenge to multigroup cross-section processing methods, which must treat each level of heterogeneity separately. A new capability to model doubly heterogeneous systems was added to the SCALE system in the release of Version 5.1. It was included in the control sequences CSAS and CSAS6, which use the Monte Carlo codes KENO V.a and KENO-VI, respectively, for three-dimensional neutron transport analyses and in the TRITON sequence, which uses the two-dimensional lattice physics code NEWT along with both versions of KENO for transport and depletion analyses. However, the SCALE 5.1 version of TRITON did not support the use of the DH approach for depletion. This deficiency has been addressed, and DH depletion will be available as an option in the upcoming release of SCALE 6. At present Oak Ridge National Laboratory (ORNL) staff are developing a set of calculations that may be used to validate SCALE for DH calculations. This paper discusses the

  3. Automatic heating and cooling system in a gas purge microsyringe extraction.

    Science.gov (United States)

    Piao, Xiangfan; Bi, Jinhu; Yang, Cui; Wang, Xiaoping; Wang, Juan; Li, Donghao

    2011-10-30

    The gas purge microsyringe extraction (GP-MSE) technique offers quantitative and simultaneous extraction, and rapid gas chromatographic-mass spectrometric determination of volatile and semivolatile chemicals is possible. To simplify the application, a new automatic temperature control system was developed here. Stable heating and cooling over a wide range of temperatures were achieved using a micro-heater and thermoelectric cooler under varying gas flow conditions. Temperatures could be accurately controlled in the range 20-350°C (heating) and 20 to -4°C (cooling). Temperature effects on the extraction performance of the GP-MSE were experimentally investigated by comparing the recoveries of polycyclic aromatic hydrocarbons (PAHs) under various experimental conditions. A sample treatment was completed within 3 min, which is much less than the time required for chromatographic analysis. The recovery of chemicals determined ranged from 81 to 96%. High reproducibility data (RSD ≤ 5%) were obtained for direct extraction of various analytes in spiked complex plant and biological samples. The data show that the heating and cooling system has potential applications in GP-MSE system for the direct determination of various kinds of volatile and semivolatile chemicals from complex matrices without any, or only minor, sample pretreatment.

  4. Redistributing hot gas around galaxies: do cool clouds signal a solution to the overcooling problem?

    CERN Document Server

    Kaufmann, Tobias; Maller, Ariyeh H; Fang, Taotao; Wadsley, James

    2008-01-01

    We present a pair of high-resolution smoothed particle hydrodynamics (SPH) simulations that explore the evolution and cooling behavior of hot gas around Milky-Way size galaxies. The simulations contain the same total baryonic mass and are identical other than their initial gas density distributions. The first is initialised with a low entropy hot gas halo that traces the cuspy profile of the dark matter, and the second is initialised with a high-entropy hot halo with a cored density profile as might be expected in models with pre-heating feedback. Galaxy formation proceeds in dramatically different fashion depending on the initial setup. While the low-entropy halo cools rapidly, primarily from the central region, the high-entropy halo is quasi-stable for ~4 Gyr and eventually cools via the fragmentation and infall of clouds from ~100 kpc distances. The low-entropy halo's X-ray surface brightness is ~100 times brighter than current limits and the resultant disc galaxy contains more than half of the system's ba...

  5. Pahs, Ionized Gas, and Molecular Hydrogen in Brightest Cluster Galaxies of Cool Core Clusters of Galaxies

    CERN Document Server

    Donahue, Megan; O'Connell, Robert W; Voit, G Mark; Hoffer, Aaron; McNamara, Brian R; Nulsen, Paul E J

    2011-01-01

    We present measurements of 5-25 {\\mu}m emission features of brightest cluster galaxies (BCGs) with strong optical emission lines in a sample of 9 cool-core clusters of galaxies observed with the Infrared Spectrograph on board the Spitzer Space Telescope. These systems provide a view of dusty molecular gas and star formation, surrounded by dense, X-ray emitting intracluster gas. Past work has shown that BCGs in cool-core clusters may host powerful radio sources, luminous optical emission line systems, and excess UV, while BCGs in other clusters never show this activity. In this sample, we detect polycyclic aromatic hydrocarbons (PAHs), extremely luminous, rotationally-excited molecular hydrogen line emission, forbidden line emission from ionized gas ([Ne II] and [Ne III]), and infrared continuum emission from warm dust and cool stars. We show here that these BCGs exhibit more luminous forbidden neon and H2 rotational line emission than star-forming galaxies with similar total infrared luminosities, as well as ...

  6. Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology

    Science.gov (United States)

    Chullen, Cinda

    2015-01-01

    Advancement of Miniature Optic Gas Sensor (MOGS) Probe Technology" project will investigate newly developed optic gas sensors delivered from a Small Business Innovative Research (SBIR) Phase II effort. A ventilation test rig will be designed and fabricated to test the sensors while integrated with a Suited Manikin Test Apparatus (SMTA). Once the sensors are integrated, a series of test points will be completed to verify that the sensors can withstand Advanced Suit Portable Life Support System (PLSS) environments and associated human metabolic profiles for changes in pressure and levels of Oxygen (ppO2), carbon dioxide (ppCO2), and humidity (ppH2O).

  7. Development of safety analysis codes and experimental validation for a very high temperature gas-cooled reactor Final report

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh

    2006-03-01

    The very high-temperature gas-cooled reactor (VHTR) is envisioned as a single- or dual-purpose reactor for electricity and hydrogen generation. The concept has average coolant temperatures above 9000C and operational fuel temperatures above 12500C. The concept provides the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperature to support process heat applications, such as coal gasification, desalination or cogenerative processes, the VHTR’s higher temperatures allow broader applications, including thermochemical hydrogen production. However, the very high temperatures of this reactor concept can be detrimental to safety if a loss-of-coolant accident (LOCA) occurs. Following the loss of coolant through the break and coolant depressurization, air will enter the core through the break by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structure and fuel. The oxidation will accelerate heatup of the reactor core and the release of toxic gasses (CO and CO2) and fission products. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. Prior to the start of this Korean/United States collaboration, no computer codes were available that had been sufficiently developed and validated to reliably simulate a LOCA in the VHTR. Therefore, we have worked for the past three years on developing and validating advanced computational methods for simulating LOCAs in a VHTR. Research Objectives As described above, a pipe break may lead to significant fuel damage and fission product release in the VHTR. The objectives of this Korean/United States collaboration were to develop and validate advanced computational methods for VHTR safety analysis. The methods that have been developed are now

  8. Studies on advanced water-cooled reactors beyond generation Ⅲ for power generation

    Institute of Scientific and Technical Information of China (English)

    CHENG Xu

    2007-01-01

    China's ambitious nuclear power program motivates the country's nuclear community to develop advanced reactor concepts beyond generation Ⅲ to ensure a long-term, stable, and sustainable development of nuclear power. The paper discusses some main criteria for the selection of future water-cooled reactors by considering the specific Chinese situation. Based on the suggested selection criteria, two new types of water-cooled reactors are recommended for future Chinese nuclear power generation. The high conversion pressurized water reactor utilizes the present PWR technology to a large extent. With a conversion ratio of about 0.95, the fuel utilization is increased about 5 times. This significantly improves the sustainability of fuel resources. The supercritical water-cooled reactor has favorable features in economics,sustainability and technology availability. It is a logical extension of the generation Ⅲ PWR technology in China.The status of international R&D work is reviewed. A new supercritieal water-cooled reactor (SCWR) core structure (the mixed reactor core) and a new fuel assembly design (two-rows FA) are proposed. The preliminary analysis using a coupled neutron-physics/thermal-hydranlics method is carded out. It shows good feasibility for the new design proposal.

  9. Stagnation region gas film cooling: Spanwise angled injection from multiple rows of holes. [gas turbine engines

    Science.gov (United States)

    Luckey, D. W.; Lecuyer, M. R.

    1981-01-01

    The stagnation region of a cylinder in a cross flow was used in experiments conducted with both a single row and multiple rows of spanwise angled (25 deg) coolant holes for a range of the coolant blowing ratio with a freestream to wall temperature ratio approximately equal to 1.7 and R(eD) = 90,000. Data from local heat flux measurements are presented for injection from a single row located at 5 deg, 22.9 deg, 40.8 deg, 58.7 deg from stagnation using a hole spacing ratio of S/d(o) = 5 and 10. Three multiple row configurations were also investigated. Data are presented for a uniform blowing distribution and for a nonuniform blowing distribution simulating a plenum supply. The data for local Stanton Number reduction demonstrated a lack of lateral spreading by the coolant jets. Heat flux levels larger than those without film cooling were observed directly behind the coolant holes as the blowing ratio exceeded a particular value. The data were spanwise averaged to illustrate the influence of injection location, blowing ratio and hole spacing. The large values of blowing ratio for the blowing distribution simulating a plenum supply resulted in heat flux levels behind the holes in excess of the values without film cooling. An increase in freestream turbulence intensity from 4.4 to 9.5 percent had a negligible effect on the film cooling performance.

  10. Gas turbine performance enhancement via utilizing different integrated turbine inlet cooling techniques

    Directory of Open Access Journals (Sweden)

    Alaa A. El-Shazly

    2016-09-01

    Full Text Available Regions that experience ambient temperatures rising during hot seasons have significant losses and impacts on both output power and efficiency of the gas turbine. When the ambient temperature increases, the air mass flow rate decreases, and hence leads to reduce the gas turbine produced power. Ambient air can be cooled by using either evaporative cooler or absorption chiller. Currently, the performance was simulated thermodynamically for a natural gas operated gas turbine. The performance was tested for the base case without any turbine inlet cooling (TIC systems and compared with the performance for both evaporative cooler and absorption chiller separately in terms of output power, thermal efficiency, heat rate, specific fuel consumption, consumed fuel mass flow rate, and economics. Results showed that at air ambient temperature equals to 37 °C and after deducting all the associated auxiliaries power consumption for both evaporative cooler and absorption chiller, the absorption chiller with regenerator can achieve an augmentation of 25.47% in power and 33.66% in efficiency which provides a saving in average power price about 13%, while the evaporative cooler provides only an increase of 5.56% in power and 1.55% in efficiency, and a saving of 3% in average power price.

  11. Cooling Properties of the Shuttle Advanced Crew Escape Spacesuit: Results of an Environmental Chamber Experiment

    Science.gov (United States)

    Hamilton, Douglas; Gillis, David; Bue, Grant; Son, Chan; Norcross, Jason; Kuznetz, Larry; Chapman, Kirt; Chhipwadia, Ketan; McBride, Tim

    2008-01-01

    The shuttle crew wears the Advanced Crew Escape Spacesuit (ACES) to protect themselves from cabin decompression and to support bail out during landing. ACES is cooled by a liquid-cooled garment (LCG) that interfaces to a heat exchanger that dumps heat into the cabin. The ACES outer layer is made of Gore-Tex(Registered TradeMark), permitting water vapor to escape while containing oxygen. The crew can only lose heat via insensible water losses and the LCG. Under nominal landing operations, the average cabin temperature rarely exceeds 75 F, which is adequate for the ACES to function. Problem A rescue shuttle will need to return 11 crew members if the previous mission suffers a thermal protection system failure, preventing it from returning safely to Earth. Initial analysis revealed that 11 crew members in the shuttle will increase cabin temperature at wheel stop above 80 F, which decreases the ACES ability to keep crew members cool. Air flow in the middeck of the shuttle is inhomogeneous and some ACES may experience much higher temperatures that could cause excessive thermal stress to crew members. Methods A ground study was conducted to measure the cooling efficiency of the ACES at 75 F, 85 F, and 95 F at 50% relative humidity. Test subjects representing 5, 50, and 95 percentile body habitus of the astronaut corps performed hand ergometry keeping their metabolic rate at 400, 600, and 800 BTU/hr for one hour. Core temperature was measured by rectal probe and skin, while inside and outside the suit. Environmental chamber wall and cooling unit inlet and outlet temperatures were measured using high-resolution thermistors ( 0.2 C). Conclusions Under these test conditions, the ACES was able to protect the core temperature of all test subjects, however thermal stress due to high insensible losses and skin temperature and skin heat flow may impact crew performance. Further research should be performed to understand the impact on cognitive performance.

  12. Development and Performance of an Advanced Ejector Cooling System for a Sustainable Built Environment

    Directory of Open Access Journals (Sweden)

    Paulo ePereira

    2015-06-01

    Full Text Available Ejector refrigeration is a promising technology for the integration into solar driven cooling systems because of its relative simplicity and low initial cost. The major drawback of such a system is associated to its relatively low coefficient of performance (COP under variable operating conditions. In order to overcome this problem, an advanced ejector was developed that changes its geometrical features depending on the upstream and downstream conditions. This paper provides a short overview of the development process and results of a small cooling capacity (1.5 kW solar driven cooling system using a variable geometry ejector. During the design steps, a number of theoretical works have been carried out, including the selection of the working fluid, the determination of the geometrical requirements and prototype design. Based on the analysis, R600a was selected as working fluid. A prototype was constructed with two independent variable geometrical factors: the area ratio and the nozzle exit position. A test rig was also assembled in order to test the ejector performance under controlled laboratory conditions and to elaborate a control algorithm for the variable geometry. Ejector performance was assessed by calculation of cooling cycle COP, entrainment ratio and critical back pressure. The results show that for a condenser pressure of 3 bar, an 80% increase in the COP was obtained when compared to the performance of a fixed geometry ejector. Experimental COP values varied between 0.4 and 0.8, depending on operating conditions. Currently the cooling cycle is being integrated into a solar driven demonstration site for long term in situ assessment.

  13. High-resolution mid-infrared spectroscopy of buffer-gas-cooled methyltrioxorhenium molecules

    CERN Document Server

    Tokunaga, Sean; Tarbutt, M; Darquié, B

    2016-01-01

    We demonstrate cryogenic buffer-gas cooling of gas-phase methyltrioxorhenium (MTO). This molecule is closely related to chiral organometallic molecules where the parity-violating energy differences between enantiomers may be measurable. The molecules are produced with a rotational temperature of approximately 6~K by laser ablation of an MTO pellet inside a cryogenic helium buffer gas cell. Facilitated by the low temperature, we demonstrate absorption spectroscopy of the 10.2~$\\mu$m antisymmetric Re=O stretching mode of MTO with a resolution of 8~MHz and a frequency accuracy of 30~MHz. We partially resolve the hyperfine structure and measure the nuclear quadrupole coupling of the excited vibrational state.

  14. Transient Load Following and Control Analysis of Advanced S-CO2 Power Conversion with Dry Air Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, Anton; Sienicki, James J.

    2016-01-01

    Supercritical carbon dioxide (S-CO2) Brayton cycles are under development as advanced energy converters for advanced nuclear reactors, especially the Sodium-Cooled Fast Reactor (SFR). The use of dry air cooling for direct heat rejection to the atmosphere ultimate heat sink is increasingly becoming a requirement in many regions due to restrictions on water use. The transient load following and control behavior of an SFR with an S-CO2 cycle power converter utilizing dry air cooling have been investigated. With extension and adjustment of the previously existing control strategy for direct water cooling, S-CO2 cycle power converters can also be used for load following operation in regions where dry air cooling is a requirement

  15. Thermodynamic formalism of minimum heat source temperature for driving advanced adsorption cooling device

    Science.gov (United States)

    Saha, Bidyut Baran; Chakraborty, Anutosh; Koyama, Shigeru; Srinivasan, Kandadai; Ng, Kim Choon; Kashiwagi, Takao; Dutta, Pradip

    2007-09-01

    This letter presents a thermodynamic formulation to calculate the minimum driving heat source temperature of an advanced solid sorption cooling device, and it is validated with experimental data. This formalism has been developed from the rigor of the Boltzmann distribution function and the condensation approximation of adsorptive molecules. An interesting and useful finding has been established from this formalism that it is possible to construct a solid sorption refrigeration device that operates in a cycle transferring heat from a low temperature source to a heat sink with a driving heat source at a temperature close to but above ambient.

  16. Cryogenic helium gas circulation system for advanced characterization of superconducting cables and other devices

    Science.gov (United States)

    Pamidi, Sastry; Kim, Chul Han; Kim, Jae-Ho; Crook, Danny; Dale, Steinar

    2012-04-01

    A versatile cryogenic test bed, based on circulating cryogenic helium gas, has been designed, fabricated, and installed at the Florida State University Center for Advanced Power Systems (FSU-CAPS). The test bed is being used to understand the benefits of integrating the cryogenic systems of multiple superconducting power devices. The helium circulation system operates with four sets of cryocooler and heat exchanger combinations. The maximum operating pressure of the system is 2.1 MPa. The efficacy of helium circulation systems in cooling superconducting power devices is evaluated using a 30-m-long simulated superconducting cable in a flexible cryostat. Experiments were conducted at various mass flow rates and a variety of heat load profiles. A 1-D thermal model was developed to understand the effect of the gas flow parameters on the thermal gradients along the cable. Experimental results are in close agreement with the results from the thermal model.

  17. Evidence for a heated gas bubble inside the "cooling flow" region of MKW3s

    CERN Document Server

    Mazzotta, P; Paerels, F B S; Ferrigno, C; Colafrancesco, Sergio; Mewe, R; Forman, W R

    2002-01-01

    We report on the deep Chandra observation of central r=200kpc region of the cluster of galaxies MKW3s which was previously identified as a moderate cooling flow cluster. The Chandra image reveals two striking features -- a 100kpc long and 21kpc wide filament, extending from the center to the south-west and a nearly circular, 50kpc diameter depression 90 kpc south of the X-ray peak. The temperature map shows that the filamentary structure is colder while the surface brightness depression is hotter than the average cluster temperature at any radius. The hot and the cold regions indicate that both cooling and heating processes are taking place in the center of MKW3s. We argue that the surface brightness depression is produced by a heated, low-density gas bubble along the line of sight. We suggest that the heated bubble is produced by short-lived nuclear outbursts from the central galaxy.

  18. EFFECTS OF COOLED EXTERNAL EXHAUST GAS RECIRCULATION ON DIESEL HOMOGENEOUS CHARGE COMPRESSION IGNITION ENGINE

    Institute of Scientific and Technical Information of China (English)

    SHI Lei; CUI Yi; DENG Kangyao

    2007-01-01

    The effects of cooled external exhaust gas recirculation (EGR) on the combustion and emission performance of diesel fuel homogeneous charge compression ignition (HCCI) are studied. Homogeneous mixture is formed by injecting fuel in-cylinder in the negative valve overlap (NVO) period. So, the HCCI combustion which has low NOx and smoke emission is achieved. Cooled external EGR can delay the start of combustion effectively, which is very useful for high cetane fuel (diesel) HCCI, because these fuels can easily self-ignition, which makes the start of combustion more early. External EGR can avoid the knock combustion of HCCI at high load which means that the EGR can expand the high load limit. HCCI maintains low smoke emission at various EGR rate and various load compared with conventional diesel engine because there is no fuel-rich area in cylinder.

  19. Measurement of Turbulent Flow Phenomena for the Lower Plenum of a Prismatic Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hugh M. McIlroy Jr.; Donald M. McEligot; Robert J. Pink; Keith G. Condie; Glenn E. McCreery

    2007-09-01

    Mean velocity field and turbulence data are presented for flow phenomena in a lower plenum of a typical prismatic gas-cooled reactor (GCR), such as in a Very High Temperature Reactor (VHTR) concept. In preparation for design, safety analyses and licensing, research has begun on readying the computational tools that will be needed to predict the thermal-hydraulics behavior of the reactor design. Fluid dynamics experiments have been designed and built to develop benchmark databases for the assessment of computational fluid dynamics (CFD) codes and their turbulence models for a typical VHTR plenum geometry in the limiting case of negligible buoyancy and constant fluid properties. This experiment has been proposed as a “Standard Problem” for assessing advanced reactor (CFD) analysis tools. Present results concentrate on the region of the plenum near its far reflector wall (away from the outlet duct). The flow in the lower plenum can locally be considered as multiple jets into a confined cross flow - with obstructions. A model of the lower plenum has been fabricated and scaled to the geometric dimensions of the Next Generation Nuclear Plant (NGNP) Point Design. The model consists of a row of full circular posts along its centerline with half-posts on the two parallel walls to induce flow features somewhat comparable to those expected from the staggered parallel rows of posts in the reactor design. Posts, side walls and end walls are fabricated from clear, fused quartz to match the refractive-index of the working fluid so that optical techniques may be employed for the measurements. The experiments were conducted in the Matched-Index-of-Refraction (MIR) Facility at the Idaho National Laboratory (INL). The benefit of the MIR technique is that it permits optical measurements to determine complex flow characteristics in passages and around objects to be obtained without locating a disturbing transducer in the flow field and without distortion of the optical paths. The

  20. The absorption and emission spectrum of radiative cooling galactic fountain gas

    Science.gov (United States)

    Benjamin, Robert A.; Shapiro, Paul R.

    1993-01-01

    We have calculated the time-dependent, nonequilibrium thermal and ionization history of gas cooling radiatively from 10(exp 6) K in a one-dimensional, planar, steady-state flow model of the galactic fountain, including the effects of radiative transfer. Our previous optically thin calculations explored the effects of photoionization on such a flow and demonstrated that self-ionization was sufficient to cause the flow to match the observed galactic halo column densities of C 4, Si 4, and N 5 and UV emission from C 4 and O 3 in the constant density (isochoric) limit, which corresponded to cooling regions homogeneous on scales D less than or approximately equal to 1 kpc. Our new calculations which take full account of radiative transfer confirm the importance of self-ionization in enabling such a flow to match the data but allow a much larger range for cooling region sizes, i.e. D(sub 0) greater than or approximately equal to 15 pc. For an initial flow velocity v(sub 0) approximately equal to 100 km/s, comparable to the sound speed of a 10(exp 6) K gas, the initial density is found to be n(sub h,0) is approximately 2 x 10(exp -2) cm(exp -3), in reasonable agreement with other observation estimates, and D(sub 0) is approximately equal to 40 pc. We also compare predicted H(alpha) fluxes, UV line emission, and broadband x-ray fluxes with observed values. One dimensional numerical hydrodynamical calculations including the effects of radiative cooling are also presented.

  1. Characterization of a cryogenically cooled high-pressure gas jet for laser/cluster interaction experiments

    Science.gov (United States)

    Smith, R. A.; Ditmire, T.; Tisch, J. W. G.

    1998-11-01

    We have developed and carried out detailed characterization of a cryogenically cooled (34-300 K), high-pressure (55 kTorr) solenoid driven pulsed valve that has been used to produce dense jets of atomic clusters for high intensity laser interaction studies. Measurements including Rayleigh scattering and short pulse interferometry show that clusters of controlled size, from a few to >104 atoms/cluster can be produced from a broad range of light and heavy gases, at average atomic densities up to 4×1019 atoms/cc. Continuous temperature and pressure control of the valve allows us to vary mean cluster size while keeping the average atomic density constant, and we find that many aspects of the valves behavior are consistent with ideal gas laws. However, we also show that effects including the build up of flow on milliseconds time scales, the cooling of gas flowing into the valve, and condensation of gas inside the valve body at temperatures well above the liquefaction point need to be carefully characterized in order to decouple the operation of the jet from the laser interaction physics.

  2. Advanced Refrigerant-Based Cooling Technologies for Information and Communication Infrastructure (ARCTIC)

    Energy Technology Data Exchange (ETDEWEB)

    Salamon, Todd

    2012-12-13

    efficiency and carbon footprint reduction for our nation's Information and Communications Technology (ICT) infrastructure. The specific objectives of the ARCTIC project focused in the following three areas: i) advanced research innovations that dramatically enhance the ability to deal with ever-increasing device heat densities and footprint reduction by bringing the liquid cooling much closer to the actual heat sources; ii) manufacturing optimization of key components; and iii) ensuring rapid market acceptance by reducing cost, thoroughly understanding system-level performance, and developing viable commercialization strategies. The project involved participants with expertise in all aspects of commercialization, including research & development, manufacturing, sales & marketing and end users. The team was lead by Alcatel-Lucent, and included subcontractors Modine and USHose.

  3. Evaporative cooling of microscopic water droplets in vacuo: Molecular dynamics simulations and kinetic gas theory.

    Science.gov (United States)

    Schlesinger, Daniel; Sellberg, Jonas A; Nilsson, Anders; Pettersson, Lars G M

    2016-03-28

    In the present study, we investigate the process of evaporative cooling of nanometer-sized droplets in vacuum using molecular dynamics simulations with the TIP4P/2005 water model. The results are compared to the temperature evolution calculated from the Knudsen theory of evaporation which is derived from kinetic gas theory. The calculated and simulation results are found to be in very good agreement for an evaporation coefficient equal to unity. Our results are of interest to experiments utilizing droplet dispensers as well as to cloud micro-physics.

  4. Development of Safety Analysis Codes and Experimental Validation for a Very High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H. Oh, PhD; Cliff Davis; Richard Moore

    2004-11-01

    The very high temperature gas-cooled reactors (VHTGRs) are those concepts that have average coolant temperatures above 900 degrees C or operational fuel temperatures above 1250 degrees C. These concepts provide the potential for increased energy conversion efficiency and for high-temperature process heat application in addition to power generation and nuclear hydrogen generation. While all the High Temperature Gas Cooled Reactor (HTGR) concepts have sufficiently high temperatures to support process heat applications, such as desalination and cogeneration, the VHTGR's higher temperatures are suitable for particular applications such as thermochemical hydrogen production. However, the high temperature operation can be detrimental to safety following a loss-of-coolant accident (LOCA) initiated by pipe breaks caused by seismic or other events. Following the loss of coolant through the break and coolant depressurization, air from the containment will enter the core by molecular diffusion and ultimately by natural convection, leading to oxidation of the in-core graphite structures and fuel. The oxidation will release heat and accelerate the heatup of the reactor core. Thus, without any effective countermeasures, a pipe break may lead to significant fuel damage and fission product release. The Idaho National Engineering and Environmental Laboratory (INEEL) has investigated this event for the past three years for the HTGR. However, the computer codes used, and in fact none of the world's computer codes, have been sufficiently developed and validated to reliably predict this event. New code development, improvement of the existing codes, and experimental validation are imperative to narrow the uncertaninty in the predictions of this type of accident. The objectives of this Korean/United States collaboration are to develop advanced computational methods for VHTGR safety analysis codes and to validate these computer codes.

  5. Efficiency of gas cooling and accretion at the disc-corona interface

    CERN Document Server

    Armillotta, L; Marinacci, F

    2016-01-01

    In star-forming galaxies, stellar feedback can have a dual effect on the circumgalactic medium both suppressing and stimulating gas accretion. The trigger of gas accretion can be caused by disc material ejected into the halo in the form of fountain clouds and by its interaction with the surrounding hot corona. Indeed, at the disc-corona interface, the mixing between the cold/metal-rich disc gas (T ~ 10^6 K) can dramatically reduce the cooling time of a portion of the corona and produce its condensation and accretion. We studied the interaction between fountain clouds and corona in different galactic environments through parsec-scale hydrodynamical simulations, including the presence of thermal conduction, a key mechanism that influences gas condensation. Our simulations showed that the coronal gas condensation strongly depends on the galactic environment, in particular it is less efficient for increasing virial temperature/mass of the haloes where galaxies reside and it is fully ineffective for objects with v...

  6. Design Concept of Advanced Sodium-Cooled Fast Reactor and Related R&D in Korea

    Directory of Open Access Journals (Sweden)

    Yeong-il Kim

    2013-01-01

    Full Text Available Korea imports about 97% of its energy resources due to a lack of available energy resources. In this status, the role of nuclear power in electricity generation is expected to become more important in future years. In particular, a fast reactor system is one of the most promising reactor types for electricity generation, because it can utilize efficiently uranium resources and reduce radioactive waste. Acknowledging the importance of a fast reactor in a future energy policy, the long-term advanced SFR development plan was authorized by KAEC in 2008 and updated in 2011 which will be carried out toward the construction of an advanced SFR prototype plant by 2028. Based upon the experiences gained during the development of the conceptual designs for KALIMER, KAERI recently developed advanced sodium-cooled fast reactor (SFR design concepts of TRU burner that can better meet the generation IV technology goals. The current status of nuclear power and SFR design technology development program in Korea will be discussed. The developments of design concepts including core, fuel, fluid system, mechanical structure, and safety evaluation have been performed. In addition, the advanced SFR technologies necessary for its commercialization and the basic key technologies have been developed including a large-scale sodium thermal-hydraulic test facility, super-critical Brayton cycle system, under-sodium viewing techniques, metal fuel development, and developments of codes, and validations are described as R&D activities.

  7. Enormous disc of cool gas surrounding the nearby powerful radio galaxy NGC 612 (PKS 0131-36)

    NARCIS (Netherlands)

    Emonts, B. H. C.; Morganti, R.; Oosterloo, T. A.; Holt, J.; Tadhunter, C. N.; van der Hulst, J. M.; Ojha, R.; Sadler, E. M.

    2008-01-01

    We present the detection of an enormous disc of cool neutral hydrogen (HI) gas surrounding the S0 galaxy NGC612, which hosts one of the nearest powerful radio sources (PKS 0131-36). Using the Australia Telescope Compact Array, we detect MHI = 1.8 x 10(9) M(circle dot) of HI emission-line gas that is

  8. A small high temperature gas cooled reactor for nuclear marine propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Brugiere, F.; Sillon, C. [Ecole des Applications Militaires de l' Energie Atomique, 50 - Cherbourg (France); Foster, A.; Hamilton, P.; Jewer, S.; Thompson, A.C. [Defence College of Electromechanical Engineering, Nuclear Dept., Military Rd, Gosport (United Kingdom); Kingston, T.; Williams, A.M.; Beeley, P.A. [Rolls-Royce (Marine Power), Raynesway, Derby (United Kingdom)

    2007-07-01

    Results from a design study for a hypothetical nuclear marine propulsion plant are presented. The plant utilizes a small High Temperature Gas Cooled Reactor (HTGCR) similar to the GTHTR300 design by the Japan Atomic Energy Agency with power being generated by a direct cycle gas turbine. The GTHTR300 design is modified in order to achieve the required power of 80 MWth and core lifetime of approximately 10 years. Thermal hydraulic analysis shows that in the event of a complete loss of flow accident the hot channel fuel temperature exceeds the 1600 Celsius degrees limit due to the high power peaking in assemblies adjacent to the inner reflector. Reactor dynamics shows oscillatory behaviour in rapid power transients. An automatic control rod system is suggested to overcome this problem. (authors)

  9. Sensitivity and resolution in frequency comb spectroscopy of buffer gas cooled polyatomic molecules

    Science.gov (United States)

    Changala, P. Bryan; Spaun, Ben; Patterson, David; Doyle, John M.; Ye, Jun

    2016-12-01

    We discuss the use of cavity-enhanced direct frequency comb spectroscopy in the mid-infrared region with buffer gas cooling of polyatomic molecules for high-precision rovibrational absorption spectroscopy. A frequency comb coupled to an optical enhancement cavity allows us to collect high-resolution, broad-bandwidth infrared spectra of translationally and rotationally cold (10-20 K) gas-phase molecules with high absorption sensitivity and fast acquisition times. The design and performance of the combined apparatus are discussed in detail. Recorded rovibrational spectra in the CH stretching region of several organic molecules, including vinyl bromide (CH_2CHBr), adamantane (C_{10}H_{16}), and diamantane (C_{14}H_{20}) demonstrate the resolution and sensitivity of this technique, as well as the intrinsic challenges faced in extending the frontier of high-resolution spectroscopy to large complex molecules.

  10. Gas cooling in semi-analytic models and SPH simulations: are results consistent?

    CERN Document Server

    Saro, A; Borgani, S; Dolag, K

    2010-01-01

    We present a detailed comparison between the galaxy populations within a massive cluster, as predicted by hydrodynamical SPH simulations and by a semi-analytic model (SAM) of galaxy formation. Both models include gas cooling and a simple prescription of star formation, which consists in transforming instantaneously any cold gas available into stars, while neglecting any source of energy feedback. We find that, in general, galaxy populations from SAMs and SPH have similar statistical properties, in agreement with previous studies. However, when comparing galaxies on an object-by-object basis, we find a number of interesting differences: a) the star formation histories of the brightest cluster galaxies (BCGs) from SAM and SPH models differ significantly, with the SPH BCG exhibiting a lower level of star formation activity at low redshift, and a more intense and shorter initial burst of star formation with respect to its SAM counterpart; b) while all stars associated with the BCG were formed in its progenitors i...

  11. Surpassing the mass restriction of buffer gas cooling: Cooling of low mass ions by localized heavier atoms

    Science.gov (United States)

    Dutta, Sourav; Sawant, Rahul; Rangwala, S. A.

    2016-05-01

    Cooling of trapped ions has resulted in fascinating science including the realization of some of the most accurate atomic clocks. It has also found widespread application, for example, in mass spectrometry and cold chemistry. Among the different methods for cooling ions, cooling by elastic collisions with ultracold neutral atoms is arguably the most generic. However, in spite of its widespread application, there is confusion with regards the collisional heating/cooling of light ions by heavier neutral atoms. We address the question experimentally and demonstrate, for the first time, cooling of light ions by co-trapped heavy atoms. We show that trapped 39 K+ ions are cooled by localized ultracold neutral 85 Rb atoms. The atom-ion mass ratio (= 2.18) is well beyond any theoretical predictions so far. We further argue that cooling of ions by localized cold atoms is possible for any mass ratio. The result opens up the possibility of reaching the elusive s-wave collision regime in atom-ion collisions. S.D. is supported by DST-INSPIRE Faculty Fellowship, India.

  12. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corp. , Columbus, Ohio. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-11-01

    The Solar Energy System located at the Columbia Gas Corporation, Columbus, Ohio, has 2978 ft/sup 2/ of Honeywell single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/h Bryan water-tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton Arkla hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts are included from the site files, specification references, drawings, installation, operation and maintenance instructions.

  13. Simulation and control of water-gas shift packed bed reactor with inter-stage cooling

    Science.gov (United States)

    Saw, S. Z.; Nandong, J.

    2016-03-01

    Water-Gas Shift Reaction (WGSR) has become one of the well-known pathways for H2 production in industries. The issue with WGSR is that it is kinetically favored at high temperatures but thermodynamically favored at low temperatures, thus requiring careful consideration in the control design in order to ensure that the temperature used does not deactivate the catalyst. This paper studies the effect of a reactor arrangement with an inter-stage cooling implemented in the packed bed reactor to look at its effect on outlet temperature. A mathematical model is developed based on one-dimensional heat and mass transfers which incorporate the intra-particle effects. It is shown that the placement of the inter-stage cooling and the outlet temperature exiting the inter-stage cooling have strong influence on the reaction conversion. Several control strategies are explored for the process. It is shown that a feedback- feedforward control strategy using Multi-scale Control (MSC) is effective to regulate the reactor temperature profile which is critical to maintaining the catalysts activity.

  14. Dark matter merging induced turbulence as an efficient engine for gas cooling

    Science.gov (United States)

    Prieto, Joaquin; Jimenez, Raul; Martí, Jose

    2012-02-01

    We have performed a cosmological numerical simulation of primordial baryonic gas collapsing on to a 3 × 107 M⊙ dark matter (DM) halo. We show that the large scale baryonic accretion process and the merger of few ˜ 106 M⊙ DM haloes, triggered by the gravitational potential of the biggest halo, are enough to create supersonic (?) shocks and develop a turbulent environment. In this scenario, the post-shocked regions are able to produce both H2 and deuterated H2 molecules very efficiently, reaching maximum abundances of ? and nHD˜ few × 10-6 nH, enough to cool the gas below 100 K in some regions. The kinetic energy spectrum of the turbulent primordial gas is close to a Burgers spectrum, ?, which could favour the formation of low-mass primordial stars. The solenoidal-to-total kinetic energy ratio is 0.65 ≲Rk≲ 0.7 for a wide range of wavenumbers; this value is close to the Rk≈ 2/3 natural equipartition energy value of a random turbulent flow. In this way, turbulence and molecular cooling seem to work together in order to produce potential star formation regions of cold dense gas in primordial environments. We conclude that both the mergers and the collapse process on to the main DM halo provide enough energy to develop supersonic turbulence which favours the molecular coolant formation: this mechanism, which could be universal and the main route towards the formation of the first galaxies, is able to create potential star-forming regions at high redshift.

  15. Western tight gas sands advanced logging workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Jennings, J B; Carroll, Jr, H B [eds.

    1982-04-01

    An advanced logging research program is one major aspect of the Western Tight Sands Program. Purpose of this workshop is to help BETC define critical logging needs for tight gas sands and to allow free interchange of ideas on all aspects of the current logging research program. Sixteen papers and abstracts are included together with discussions. Separate abstracts have been prepared for the 12 papers. (DLC)

  16. Gas-Cooled Thorium Reactor with Fuel Block of the Unified Design

    Directory of Open Access Journals (Sweden)

    Igor Shamanin

    2015-01-01

    Full Text Available Scientific researches of new technological platform realization carried out in Russia are based on ideas of nuclear fuel breeding in closed fuel cycle and physical principles of fast neutron reactors. Innovative projects of low-power reactor systems correspond to the new technological platform. High-temperature gas-cooled thorium reactors with good transportability properties, small installation time, and operation without overloading for a long time are considered perspective. Such small modular reactor systems at good commercial, competitive level are capable of creating the basis of the regional power industry of the Russian Federation. The analysis of information about application of thorium as fuel in reactor systems and its perspective use is presented in the work. The results of the first stage of neutron-physical researches of a 3D model of the high-temperature gas-cooled thorium reactor based on the fuel block of the unified design are given. The calculation 3D model for the program code of MCU-5 series was developed. According to the comparison results of neutron-physical characteristics, several optimum reactor core compositions were chosen. The results of calculations of the reactivity margins, neutron flux distribution, and power density in the reactor core for the chosen core compositions are presented in the work.

  17. On the quasihydrostatic flows of radiatively cooling self-gravitating gas clouds

    Energy Technology Data Exchange (ETDEWEB)

    Meerson, B.; Megged, E. [Hebrew Univ. of Jerusalem (Israel). Racah Institute of Physics; Tajima, T. [Univ. of Texas, Austin, TX (United States)

    1995-03-01

    Two model problems are considered, illustrating the dynamics of quasihydrostatic flows of radiatively cooling, optically thin self-gravitating gas clouds. In the first problem, spherically symmetric flows in an unmagnetized plasma are considered. For a power-law dependence of the radiative loss function on the temperature, a one-parameter family of self-similar solutions is found. The authors concentrate on a constant-mass cloud, one of the cases, when the self-similarity indices are uniquely selected. In this case, the self-similar flow problem can be formally reduced to the classical Lane-Emden equation and therefore solved analytically. The cloud is shown to undergo radiative condensation, if the gas specific heat ratio {gamma} > 4/3. The condensation proceeds either gradually, or in the form of (quasihydrostatic) collapse. For {gamma} < 4/3, the cloud is shown to expand. The second problem addresses a magnetized plasma slab that undergoes quasihydrostatic radiative cooling and condensation. The problem is solved analytically, employing the Lagrangian mass coordinate.

  18. Test case specifications for coupled neutronics-thermal hydraulics calculation of Gas-cooled Fast Reactor

    Science.gov (United States)

    Osuský, F.; Bahdanovich, R.; Farkas, G.; Haščík, J.; Tikhomirov, G. V.

    2017-01-01

    The paper is focused on development of the coupled neutronics-thermal hydraulics model for the Gas-cooled Fast Reactor. It is necessary to carefully investigate coupled calculations of new concepts to avoid recriticality scenarios, as it is not possible to ensure sub-critical state for a fast reactor core under core disruptive accident conditions. Above mentioned calculations are also very suitable for development of new passive or inherent safety systems that can mitigate the occurrence of the recriticality scenarios. In the paper, the most promising fuel material compositions together with a geometry model are described for the Gas-cooled fast reactor. Seven fuel pin and fuel assembly geometry is proposed as a test case for coupled calculation with three different enrichments of fissile material in the form of Pu-UC. The reflective boundary condition is used in radial directions of the test case and vacuum boundary condition is used in axial directions. During these condition, the nuclear system is in super-critical state and to achieve a stable state (which is numerical representation of operational conditions) it is necessary to decrease the reactivity of the system. The iteration scheme is proposed, where SCALE code system is used for collapsing of a macroscopic cross-section into few group representation as input for coupled code NESTLE.

  19. Combined cooling and heating using a gas engine in a supermarket

    Energy Technology Data Exchange (ETDEWEB)

    Maidment, G.G. [South Bank Univ., London (United Kingdom). School of Engineering Systems and Design; Zhao, X.; Riffat, S.B. [Nottingham Univ. (United Kingdom). School of the Built Environment

    2001-07-01

    This paper reports the results of an investigation into the practical and economic viability of an integrated combined heating and cooling system in a supermarket. This system consists of a direct-drive screw compressor, which is powered by a throttle controlled gas engine. The waste heat from the engine is used to provide hot water for space heating and for general usage within the catering and toilet facilities in the supermarket. In this paper, the working principle of the novel system is first described. This details how the gas engine system may be integrated into the typical supermarket. The paper then describes a model, which is used to simulate the energy consumption of the supermarket. This is used to calculate the energy consumed by the conventional system and that used by a number of alternative combined heating and cooling system configurations, which are also described. The additional capital cost of each configuration is estimated and this is used to calculate the payback period. The results show that a payback period of 4.2 years may be achieved with a system that uses approximately 500,000 kWh per annum less primary energy than a conventional system. Finally, comparison between this system and a traditional Combined Heat and Power (CHP) installation is given. (author)

  20. Advanced Coal-Fueled Gas Turbine Program. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Horner, M.W.; Ekstedt, E.E.; Gal, E.; Jackson, M.R.; Kimura, S.G.; Lavigne, R.G.; Lucas, C.; Rairden, J.R.; Sabla, P.E.; Savelli, J.F.; Slaughter, D.M.; Spiro, C.L.; Staub, F.W.

    1989-02-01

    The objective of the original Request for Proposal was to establish the technological bases necessary for the subsequent commercial development and deployment of advanced coal-fueled gas turbine power systems by the private sector. The offeror was to identify the specific application or applications, toward which his development efforts would be directed; define and substantiate the technical, economic, and environmental criteria for the selected application; and conduct such component design, development, integration, and tests as deemed necessary to fulfill this objective. Specifically, the offeror was to choose a system through which ingenious methods of grouping subcomponents into integrated systems accomplishes the following: (1) Preserve the inherent power density and performance advantages of gas turbine systems. (2) System must be capable of meeting or exceeding existing and expected environmental regulations for the proposed application. (3) System must offer a considerable improvement over coal-fueled systems which are commercial, have been demonstrated, or are being demonstrated. (4) System proposed must be an integrated gas turbine concept, i.e., all fuel conditioning, all expansion gas conditioning, or post-expansion gas cleaning, must be integrated into the gas turbine system.

  1. THATCH: A computer code for modelling thermal networks of high- temperature gas-cooled nuclear reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kroeger, P.G.; Kennett, R.J.; Colman, J.; Ginsberg, T. (Brookhaven National Lab., Upton, NY (United States))

    1991-10-01

    This report documents the THATCH code, which can be used to model general thermal and flow networks of solids and coolant channels in two-dimensional r-z geometries. The main application of THATCH is to model reactor thermo-hydraulic transients in High-Temperature Gas-Cooled Reactors (HTGRs). The available modules simulate pressurized or depressurized core heatup transients, heat transfer to general exterior sinks or to specific passive Reactor Cavity Cooling Systems, which can be air or water-cooled. Graphite oxidation during air or water ingress can be modelled, including the effects of added combustion products to the gas flow and the additional chemical energy release. A point kinetics model is available for analyzing reactivity excursions; for instance due to water ingress, and also for hypothetical no-scram scenarios. For most HTGR transients, which generally range over hours, a user-selected nodalization of the core in r-z geometry is used. However, a separate model of heat transfer in the symmetry element of each fuel element is also available for very rapid transients. This model can be applied coupled to the traditional coarser r-z nodalization. This report described the mathematical models used in the code and the method of solution. It describes the code and its various sub-elements. Details of the input data and file usage, with file formats, is given for the code, as well as for several preprocessing and postprocessing options. The THATCH model of the currently applicable 350 MW{sub th} reactor is described. Input data for four sample cases are given with output available in fiche form. Installation requirements and code limitations, as well as the most common error indications are listed. 31 refs., 23 figs., 32 tabs.

  2. The development of advanced cooling methods for high-power electronics

    Science.gov (United States)

    Bland, T. J.; Ciaccio, M. P.; Downing, R. S.; Smith, W. G.

    1990-10-01

    Consideration is given to various technologies developed to meet the difficult cooling requirements of high-density power electronics equipment for the aerospace industry. Topics discussed include liquid impingement cooling, compact high-density cooler, integrally cooled semiconductor, high heat flux cold plane, immersion cooling, modular reflux cooler, and forced-flow two-phase cooling systems. It is concluded that the new technologies are capable of providing the temperature control necessary to maintain desired electronic reliabilities using high-conductance cooling approaches.

  3. NOT DEAD YET: COOL CIRCUMGALACTIC GAS IN THE HALOS OF EARLY-TYPE GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Thom, Christopher; Tumlinson, Jason; Sembach, Kenneth R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Werk, Jessica K.; Xavier Prochaska, J. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, P.O. Box 9513, NL-2300 RA Leiden (Netherlands); Peeples, Molly S. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095 (United States); Tripp, Todd M.; Katz, Neal S. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003-9305 (United States); O' Meara, John M. [Department of Chemistry and Physics, Saint Michael' s College, Colchester, VT 05439 (United States); Ford, Amanda Brady; Dave, Romeel [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Weinberg, David H. [Department of Astronomy, Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States)

    2012-10-20

    We report new observations of circumgalactic gas in the halos of early-type galaxies (ETGs) obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. We find that detections of H I surrounding ETGs are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations. For ETGs, the covering fraction for H I absorption above 10{sup 16} cm{sup -2} is {approx}40%-50% within {approx}150 kpc. Line widths and kinematics of the detected material show it to be cold (T {approx}< 10{sup 5} K) in comparison to the virial temperature of the host halos. The implied masses of cool, photoionized circumgalactic medium baryons may be up to 10{sup 9}-10{sup 11} M{sub Sun }. Contrary to some theoretical expectations, strong halo H I absorbers do not disappear as part of the quenching of star formation. Even passive galaxies retain significant reservoirs of halo baryons that could replenish the interstellar gas reservoir and eventually form stars. This halo gas may feed the diffuse and molecular gas that is frequently observed inside ETGs.

  4. The Cool ISM in S0 Galaxies. I. A Survey of Molecular Gas

    CERN Document Server

    Welch, G A; Welch, Gary A.; Sage, Leslie J.

    2003-01-01

    Lenticular galaxies remain remarkably mysterious as a class. Observations to date have not led to any broad consensus about their origins, properties and evolution, though they are often thought to have formed in one big burst of star formation early in the history of the Universe, and to have evolved relatively passively since then. In that picture, current theory predicts that stellar evolution returns substantial quantities of gas to the interstellar medium; most is ejected from the galaxy, but significant amounts of cool gas might be retained. Past searches for that material, though, have provided unclear results. We present results from a survey of molecular gas in a volume-limited sample of field S0 galaxies, selected from the Nearby Galaxies Catalog. CO emission is detected from 78 percent of the sample galaxies. We find that the molecular gas is almost always located inside the central few kiloparses of a lenticular galaxy, meaning that in general it is more centrally concentrated than in spirals. We ...

  5. Advanced coal-fueled industrial cogeneration gas turbine system

    Energy Technology Data Exchange (ETDEWEB)

    LeCren, R.T.; Cowell, L.H.; Galica, M.A.; Stephenson, M.D.; Wen, C.S.

    1991-07-01

    Advances in coal-fueled gas turbine technology over the past few years, together with recent DOE-METC sponsored studies, have served to provide new optimism that the problems demonstrated in the past can be economically resolved and that the coal-fueled gas turbine can ultimately be the preferred system in appropriate market application sectors. The objective of the Solar/METC program is to prove the technical, economic, and environmental feasibility of a coal-fired gas turbine for cogeneration applications through tests of a Centaur Type H engine system operated on coal fuel throughout the engine design operating range. The five-year program consists of three phases, namely: (1) system description; (2) component development; (3) prototype system verification. A successful conclusion to the program will initiate a continuation of the commercialization plan through extended field demonstration runs.

  6. ADVANCED UNDERGROUND GAS STORAGE CONCEPTS REFRIGERATED-MINED CAVERN STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-01

    Limited demand and high cost has prevented the construction of hard rock caverns in this country for a number of years. The storage of natural gas in mined caverns may prove technically feasible if the geology of the targeted market area is suitable; and economically feasible if the cost and convenience of service is competitive with alternative available storage methods for peak supply requirements. It is believed that mined cavern storage can provide the advantages of high delivery rates and multiple fill-withdrawal cycles in areas where salt cavern storage is not possible. In this research project, PB-KBB merged advanced mining technologies and gas refrigeration techniques to develop conceptual designs and cost estimates to demonstrate the commercialization potential of the storage of refrigerated natural gas in hard rock caverns. Five regions of the U.S.A. were studied for underground storage development and PB-KBB reviewed the literature to determine if the geology of these regions was suitable for siting hard rock storage caverns. Area gas market conditions in these regions were also studied to determine the need for such storage. Based on an analysis of many factors, a possible site was determined to be in Howard and Montgomery Counties, Maryland. The area has compatible geology and a gas industry infrastructure for the nearby market populous of Baltimore and Washington D.C.. As Gas temperature is lowered, the compressibility of the gas reaches an optimum value. The compressibility of the gas, and the resultant gas density, is a function of temperature and pressure. This relationship can be used to commercial advantage by reducing the size of a storage cavern for a given working volume of natural gas. This study looks at this relationship and and the potential for commercialization of the process in a storage application. A conceptual process design, and cavern design were developed for various operating conditions. Potential site locations were considered

  7. Advances in liquid metal cooled ADS systems, and useful results for the design of IFMIF

    Energy Technology Data Exchange (ETDEWEB)

    Massaut, V.; Debruyn, D. [SCK CEN, Mol (Belgium); Decreton, M. [Ghent Univ., Dept. of Applied Physics (Belgium)

    2007-07-01

    Full text of publication follows: Liquid metal cooled Accelerator Driven Systems (ADS) have a lot of design commonalities with the design of IFMIF. The use of a powerful accelerator and a liquid metal spallation source makes it similar to the main features of the IFMIF irradiator. Developments in the field of liquid metal ADS can thus be very useful for the design phase of IFMIF, and synergy between both domains should be enhanced to avoid dubbing work already done. The liquid metal ADS facilities are developed for testing materials under high fast (> 1 MeV) neutron flux, and also for studying the transmutation of actinides as foreseen in the P and T (Partitioning and Transmutation) strategy of future fission industry. The ADS are mostly constituted of a sub-critical fission fuel assembly matrix, a spallation source (situated at the centre of the fuel arrangement) and a powerful accelerator targeting the spallation source. In liquid metal ADS, the spallation source is a liquid metal (like Pb-Bi) which is actively cooled to remove the power generated by the particle beam, spallation reactions and neutrons. Based on an advanced ADS design (e.g. the MYRRHA/XT-ADS facility), the paper shows the various topics which are common for both facilities (ADS and IFMIF) and highlights their respective specificities, leading to focused R and D activities. This would certainly cover the common aspects related to high power accelerators, liquid metal targets and beam-target coupling. But problems of safety, radioprotection, source heating and cooling, neutrons shielding, etc... lead also to common features and developments. Results already obtained for the ADS development will illustrate this synergy. This paper will therefore allow to take profit of recent developments in both fission and fusion programs and enhance the collaboration among the R and D teams in both domains. (authors)

  8. Progress towards the Advanced Cryogenic Gas Stopper at NSCL

    Science.gov (United States)

    Lund, Kasey; Bollen, Georg; Villiari, Antonio; Lawton, Don; Morrissey, Dave; Otterson, Jack; Ringle, Ryan; Schwarz, Stefan; Sumithrarachchi, Chandana; Yurkon, John; Advanced Cryogenic Gas Stopper Design Team

    2016-09-01

    Beam stopping is the key to performing experiments with low-energy beams of rare isotopes produced by projectile fragmentation. Linear gas stoppers filled with helium have become reliable tools to accomplish this task. Further developments are underway to maximize efficiency and beam rate capability in order to increase scientific reach. Improvements include increasing extraction efficiency, lowering decay losses due to slow transport time, reducing molecular combination of the isotope of interest with background impurity gases, and minimizing space charge effects. The ACGS under construction at NSCL is designed to increase performance by overcoming some of the more common issues. The use of a 4-phase RF wire carpet to generate an electrical traveling wave speeds up the ion transport times. Cryogenic cooling of the helium gas chamber reduces molecular ion information. A geometry that puts the RF carpet in the mid-plane of the gas stopper alleviates space charge effects. Prototype testing of important ACGS components has been completed, specifically ion transport tests of the newly designed RF wire carpets. Transport efficiencies up to 95% were demonstrated as well as transport speeds up to 100 m/s. RC104100.7301.

  9. Contributions to the neutronic analysis of a gas-cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Martin-del-Campo, Cecilia, E-mail: cecilia.martin.del.campo@gmail.com [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Reyes-Ramirez, Ricardo, E-mail: ricarera@yahoo.com.mx [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Francois, Juan-Luis, E-mail: juan.luis.francois@gmail.com [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico); Reinking-Cejudo, Arturo G., E-mail: reinking@servidor.unam.mx [Departamento de Sistemas Energeticos, Facultad de Ingenieria, Universidad Nacional Autonoma de Mexico, Paseo Cuauhnahuac 8532. Jiutepec, Morelos (Mexico)

    2011-06-15

    Highlights: > Differences on reactivity with MCNPX and TRIPOLI-4 are negligible. > Fuel lattice and core criticality calculations were done. > A higher Doppler coefficient than coolant density coefficient. > Zirconium carbide is a better reflector than silicon carbide. > Adequate active height, radial size and reflector thickness were obtained. - Abstract: In this work the Monte Carlo codes MCNPX and TRIPOLI-4 were used to perform the criticality calculations of the fuel assembly and the core configuration of a gas-cooled fast reactor (GFR) concept, currently in development. The objective is to make contributions to the neutronic analysis of a gas-cooled fast reactor. In this study the fuel assembly is based on a hexagonal lattice of fuel-pins. The materials used are uranium and plutonium carbide as fuel, silicon carbide as cladding, and helium gas as coolant. Criticality calculations were done for a fuel assembly where the axial reflector thickness was varied in order to find the optimal thickness. In order to determine the best material to be used as a reflector, in the reactor core with neutrons of high energy spectrum, criticality calculations were done for three reflector materials: zirconium carbide, silicon carbide and natural uranium. It was found that the zirconium carbide provides the best neutron reflection. Criticality calculations using different active heights were done to determine the optimal height, and the reflector thickness was adjusted. Core criticality calculations were performed with different radius sizes to determine the active radial dimension of the core. A negative temperature coefficient of reactivity was verified for the fuel. The effect on reactivity produced by changes in the coolant density was also evaluated. We present the main neutronic characteristics of a preliminary fuel and core designs for the GFR concept. ENDF-VI cross-sections libraries were used in both the MCNPX and TRIPOLI-4 codes, and we verified that the obtained

  10. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    1999-10-14

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas The effort during the reporting period has been devoted to development of an advanced hot-gas process that can eliminate the problematic SO{sub 2} tail gas and yield elemental sulfur

  11. BIOMASS GASIFICATION AND POWER GENERATION USING ADVANCED GAS TURBINE SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    David Liscinsky

    2002-10-20

    A multidisciplined team led by the United Technologies Research Center (UTRC) and consisting of Pratt & Whitney Power Systems (PWPS), the University of North Dakota Energy & Environmental Research Center (EERC), KraftWork Systems, Inc. (kWS), and the Connecticut Resource Recovery Authority (CRRA) has evaluated a variety of gasified biomass fuels, integrated into advanced gas turbine-based power systems. The team has concluded that a biomass integrated gasification combined-cycle (BIGCC) plant with an overall integrated system efficiency of 45% (HHV) at emission levels of less than half of New Source Performance Standards (NSPS) is technically and economically feasible. The higher process efficiency in itself reduces consumption of premium fuels currently used for power generation including those from foreign sources. In addition, the advanced gasification process can be used to generate fuels and chemicals, such as low-cost hydrogen and syngas for chemical synthesis, as well as baseload power. The conceptual design of the plant consists of an air-blown circulating fluidized-bed Advanced Transport Gasifier and a PWPS FT8 TwinPac{trademark} aeroderivative gas turbine operated in combined cycle to produce {approx}80 MWe. This system uses advanced technology commercial products in combination with components in advanced development or demonstration stages, thereby maximizing the opportunity for early implementation. The biofueled power system was found to have a levelized cost of electricity competitive with other new power system alternatives including larger scale natural gas combined cycles. The key elements are: (1) An Advanced Transport Gasifier (ATG) circulating fluid-bed gasifier having wide fuel flexibility and high gasification efficiency; (2) An FT8 TwinPac{trademark}-based combined cycle of approximately 80 MWe; (3) Sustainable biomass primary fuel source at low cost and potentially widespread availability-refuse-derived fuel (RDF); (4) An overall integrated

  12. Increasing of the gas turbine efficiency by inlet air cooling; Aumento da eficiencia de turbinas a gas por resfriamento do ar de admissao

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Flavio Barboza [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas]. E-mail: fcampos@cenpes.petrobras.com.br; Landa, Henrique Gerken de [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas. Pesquisa, Desenvolvimento e Engenharia de Gas e Energia]. E-mail: hlanda@cenpes.petrobras.com.br

    2002-07-01

    The performance of most of gas turbines are affected by the temperature and pressure environmental conditions. The turbine power and efficiency are reduced by either the increasing in the temperature ou reducing the environmental pressure. This paper analyses the turbine inlet air cooling as an alternative for increasing the turbine efficiency. The various cooling routes of the turbine inlet air, found in the literature examined are presented and discussed.

  13. Case study on natural gas application for district heating and cooling in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Maues, Jair Arone [Pontificia Universidade Catolica do Rio de Janeiro (IE/PUC-Rio), Rio de Janeiro, RJ (Brazil). Inst. de Energia; Akiyama, Junichi [Mitsui Gas e Energia do Brasil Ltda., Rio de janeiro, RJ (Brazil)

    2012-07-01

    The distributed cogeneration applying natural gas consists in an excellent alternative to use this source, but it is limited by a compatible heat demand that must be found in its application. District heating and cooling solutions can overcome this hurdle, especially in Brazil, a tropical country, where new industrial and commercial enterprises usually install central air conditioning systems. By 2020 natural gas demand shall reach a value of more than 200 MM m{sup 3} per day, accordingly to the Brazilian Energy Research Office (EPE, 2011). An expressive part of it could be consumed in cogeneration systems like the one described in this paper. This project had a special taxes exception rule applied. The chilled water and heated thermal oil produced were not taxed at all. But these two DHC utilities could obtain a different treatment if someone considers this is a tricky way of power and heat trading, which should be taxed as electricity and natural gas normally are. A bolder legislation with respect to the export of energy surplus would facilitate the project and operation of this kind of system, because the basic premise would be to attend the thermal demand with the electrical power installed, maximizing the global efficiency of the installation. An average 8 GW of Brazilian power demand, with roughly 50 MMm{sup 3}/day of natural gas consumption, could be attended by distributed energy gas cogeneration enterprises. If this prediction were totally accomplished it would bring the Brazilian participation of distributed energy in total power generation to values close to 10% in 2020, value already reached in average by the world biggest electricity's consumer countries (WADE, 2006). This also would mean an equivalent investment economy of approximately 11,000 MW in transmission and distribution lines capacity (author)

  14. Dark matter merging induced turbulence as an efficient engine for gas cooling

    CERN Document Server

    Prieto, Joaquin; Martí, Jose

    2011-01-01

    We have performed a cosmological numerical simulation of primordial baryonic gas collapsing onto a $3\\times10^7$M$_{\\odot}$ dark matter (DM) halo. We show that the large scale baryonic accretion process and the merger of few $\\sim10^6$ M$_{\\odot}$ DM halos, triggered by the gravitational potential of the biggest halo, is enough to create super sonic ($\\mathcal{M}>10$) shocks and develop a turbulent environment. In this scenario the post shocked regions are able to produced both H$_2$ and HD molecules very efficiently reaching maximum abundances of $n_\\mathrm{H_2}\\sim10^{-2}n_\\mathrm{H}$ and $n_\\mathrm{HD}\\sim \\mathrm{few}\\times10^{-6}n_\\mathrm{H}$, enough to cool the gas below 100K in some regions. The kinetic energy spectrum of the turbulent primordial gas is close to a Burgers spectrum, $\\hat{E}_k\\propto k^{-2}$, and the solenoidal to total kinetic energy ratio is $0.65\\la R_k\\la0.7$ for a wide range of wave numbers; this value is close to $R_k\\approx 2/3$ natural equipartition energy value of a random turb...

  15. Leakage Currents and Gas Generation in Advanced Wet Tantalum Capacitors

    Science.gov (United States)

    Teverovsky, Alexander

    2015-01-01

    Currently, military grade, established reliability wet tantalum capacitors are among the most reliable parts used for space applications. This has been achieved over the years by extensive testing and improvements in design and materials. However, a rapid insertion of new types of advanced, high volumetric efficiency capacitors in space systems without proper testing and analysis of degradation mechanisms might increase risks of failures. The specifics of leakage currents in wet electrolytic capacitors is that the conduction process is associated with electrolysis of electrolyte and gas generation resulting in building up of internal gas pressure in the parts. The risk associated with excessive leakage currents and increased pressure is greater for high value advanced wet tantalum capacitors, but it has not been properly evaluated yet. In this work, in Part I, leakages currents in various types of tantalum capacitors have been analyzed in a wide range of voltages, temperatures, and time under bias. Gas generation and the level of internal pressure have been calculated in Part II for different case sizes and different hermeticity leak rates to assess maximal allowable leakage currents. Effects related to electrolyte penetration to the glass seal area have been studied and the possibility of failures analyzed in Part III. Recommendations for screening and qualification to reduce risks of failures have been suggested.

  16. Development of advanced sorbents for hot gas desulfurization

    Energy Technology Data Exchange (ETDEWEB)

    Abbasian, J.; Slimane, R.B.; Wangerow, J.R. [Inst. of Gas Technology, Des Plaines, IL (United States); Cicero, D.C. [Dept. of Energy, Morgantown, WV (United States). Morgantown Energy Technology Center

    1996-12-31

    Integrated Gasification Combined-Cycle (IGCC) processes are among the leading contenders for the production of electricity from coal. Coal gas desulfurization to sufficiently low levels at elevated temperatures (T > 350 C) is now recognized as crucial to efficient and economic coal utilization in advanced IGCC processes. The implementation of hot coal gas desulfurization relies heavily on the development of regenerable sorbent materials which can efficiently reduce H{sub 2}S from several thousand ppmv levels down to a few ppmv over many cycles of sulfidation/regeneration. Zinc-based sorbents, such as zinc titanate, are currently the leading candidate sorbents, however, they have been shown to suffer from zinc volatilization at elevated temperatures leading to sorbent deterioration, increasing sorbent replacement costs, and the overall cost of hot gas cleanup. This paper discusses the results obtained in an ongoing investigation geared towards developing advanced mixed-metal oxide sorbents for desulfurization of coal-derived fuel gases in the temperature range of 350 to 550 C. The paper focuses on the study related to the development of durable sorbents and addresses thermodynamic considerations, sulfidation kinetics, regenerability, and long term durability of a number of novel sorbents.

  17. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    Science.gov (United States)

    1980-01-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  18. Gas-Cooled Fast Reactor: A Historical Overview and Future Outlook

    Directory of Open Access Journals (Sweden)

    W. F. G. van Rooijen

    2009-01-01

    Full Text Available A review is given of developments in the area of Gas-Cooled Fast Reactors (GCFR in the period from roughly 1960 until 1980. During that period, the GCFR concept was expected to increase the breeding gain, the thermal efficiency of a nuclear power plant, and alleviate some of the problems associated with liquid metal coolants. During this period, the GCFR concept was found to be more challenging than liquid-metal-cooled reactors, and none were ever constructed. In the second part of the paper, we provide an overview of the investigations on GCFR since the year 2000, when the Generation IV Initiative rekindled interest in this reactor type. The new GCFR concepts focus primarily on sustainable nuclear power, with very efficient resource use, minimum waste, and a very strong focus on (passive safety. An overview is presented of the main design characteristics of these Gen IV GCFRs, and a literature list is provided to guide the interested reader towards more detailed publications.

  19. An ytterbium quantum gas microscope with narrow-line laser cooling

    Science.gov (United States)

    Yamamoto, Ryuta; Kobayashi, Jun; Kato, Kohei; Kuno, Takuma; Sakura, Yuto; Takahashi, Yoshiro

    2016-05-01

    Single-site resolved imaging of alkali metal in a two-dimensional optical lattice (Quantum Gas Microscope, QGM) is realized and enables us to directly observe the in-trap atom distribution and study quantum dynamics with single-site resolution. It is important to extend the applicability of a QGM technique to two-electron atoms such as alkaline-earth metal and ytterbium (Yb) atoms because it opens up many unique possibilities for the quantum simulation and quantum information research. Differently from the first report on single-site resolved imaging of Yb atoms with a long lattice constant 544 nm and a short lifetime of 62 μs without cooling, we successfully realize the QGM of Yb atoms with a short lattice constant 266 nm, in which we achieve a high-resolution imaging with a low temperature of 7.4 μK and a long lifetime of 7 s by narrow-line laser cooling. The high detection fidelity of 87(2) % is achieved in our method. In addition, we are developing a different mode of QGM for Yb atoms.

  20. Safety and licensing of MHTGR (Modular High Temperature Gas Cooled Reactor)

    Energy Technology Data Exchange (ETDEWEB)

    Silady, F.A.; Millunzi, A.C.; Kelley, A.P. Jr.; Cunliffe, J.

    1987-07-01

    The Modular High Temperature Gas Cooled Reactor (MHTGR) design meets stringent top-level regulatory and user safety requirements that require that the normal and off-normal operation of the plant not disturb the public's day-to-day activities. Quantitative, top-level regulatory criteria have been specified from US NRC and EPA sources to guide the design. The user/utility group has further specified that these criteria be met at the plant boundary. The focus of the safety approach has then been centered on retaining the radionuclide inventory within the fuel by removing core heat, controlling chemical attack, and by controlling heat generation. The MHTGR is shown to passively meet the stringent requirements with margin. No operator action is required and the plant is insensitive to operator error.

  1. Simultaneous approach for simulation of a high-temperature gas-cooled reactor

    Institute of Scientific and Technical Information of China (English)

    Yang CHEN; Jiang-hong YOU; Zhi-jiang SHAO; Ke-xin WANG; Ji-xin QIAN

    2011-01-01

    The simulation of a high-temperature gas-cooled reactor pebble-bed module (HTR-PM) plant is discussed.This lumped parameter model has the form of a set differential algebraic equations (DAEs) that include stiff equations to model point neutron kinetics.The nested approach is the most common method to solve DAE,but this approach is very expensive and time-consuming due to inner iterations.This paper deals with an alternative approach in which a simultaneous solution method is used.The DAEs are discretized over a time horizon using collocation on finite elements,and Radau collocation points are applied.The resulting nonlinear algebraic equations can be solved by existing solvers.The discrete algorithm is discussed in detail; both accuracy and stability issues are considered.Finally,the simulation results are presented to validate the efficiency and accuracy of the simultaneous approach that takes much less time than the nested one.

  2. High temperature gas-cooled reactor (HTGR) graphite pebble fuel: Review of technologies for reprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Mcwilliams, A. J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-08

    This report reviews literature on reprocessing high temperature gas-cooled reactor graphite fuel components. A basic review of the various fuel components used in the pebble bed type reactors is provided along with a survey of synthesis methods for the fabrication of the fuel components. Several disposal options are considered for the graphite pebble fuel elements including the storage of intact pebbles, volume reduction by separating the graphite from fuel kernels, and complete processing of the pebbles for waste storage. Existing methods for graphite removal are presented and generally consist of mechanical separation techniques such as crushing and grinding chemical techniques through the use of acid digestion and oxidation. Potential methods for reprocessing the graphite pebbles include improvements to existing methods and novel technologies that have not previously been investigated for nuclear graphite waste applications. The best overall method will be dependent on the desired final waste form and needs to factor in the technical efficiency, political concerns, cost, and implementation.

  3. Power flattening on modified CANDLE small long life gas-cooled fast reactor

    Energy Technology Data Exchange (ETDEWEB)

    Monado, Fiber [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung, Indonesia and Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Su' ud, Zaki; Waris, Abdul; Basar, Khairul [Nuclear Physics and Biophysics Research Group, Dept. of Physics, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, Bandung (Indonesia); Ariani, Menik [Dept. of Physics, Faculty of Mathematics and Natural Sciences, Sriwijaya University (Indonesia); Sekimoto, Hiroshi [CRINES, Tokyo Institute of Technology, O-okoyama, Meguro-ku, Tokyo 152-8550 (Japan)

    2014-09-30

    Gas-cooled Fast Reactor (GFR) is one of the candidates of next generation Nuclear Power Plants (NPPs) that expected to be operated commercially after 2030. In this research conceptual design study of long life 350 MWt GFR with natural uranium metallic fuel as fuel cycle input has been performed. Modified CANDLE burn-up strategy with first and second regions located near the last region (type B) has been applied. This reactor can be operated for 10 years without refuelling and fuel shuffling. Power peaking reduction is conducted by arranging the core radial direction into three regions with respectively uses fuel volume fraction 62.5%, 64% and 67.5%. The average power density in the modified core is about 82 Watt/cc and the power peaking factor decreased from 4.03 to 3.43.

  4. High Temperature Gas-Cooled Reactor Projected Markets and Preliminary Economics

    Energy Technology Data Exchange (ETDEWEB)

    Larry Demick

    2011-08-01

    This paper summarizes the potential market for process heat produced by a high temperature gas-cooled reactor (HTGR), the environmental benefits reduced CO2 emissions will have on these markets, and the typical economics of projects using these applications. It gives examples of HTGR technological applications to industrial processes in the typical co-generation supply of process heat and electricity, the conversion of coal to transportation fuels and chemical process feedstock, and the production of ammonia as a feedstock for the production of ammonia derivatives, including fertilizer. It also demonstrates how uncertainties in capital costs and financial factors affect the economics of HTGR technology by analyzing the use of HTGR technology in the application of HTGR and high temperature steam electrolysis processes to produce hydrogen.

  5. Review of ORNL-TSF shielding experiments for the gas-cooled Fast Breeder Reactor Program

    Energy Technology Data Exchange (ETDEWEB)

    Abbott, L.S.; Ingersoll, D.T.; Muckenthaler, F.J.; Slater, C.O.

    1982-01-01

    During the period between 1975 and 1980 a series of experiments was performed at the ORNL Tower Shielding Facility in support of the shield design for a 300-MW(e) Gas Cooled Fast Breeder Demonstration Plant. This report reviews the experiments and calculations, which included studies of: (1) neutron streaming in the helium coolant passageways in the GCFR core; (2) the effectiveness of the shield designed to protect the reactor grid plate from radiation damage; (3) the adequacy of the radial shield in protecting the PCRV (prestressed concrete reactor vessel) from radiation damage; (4) neutron streaming between abutting sections of the radial shield; and (5) the effectiveness of the exit shield in reducing the neutron fluxes in the upper plenum region of the reactor.

  6. Depletion Analysis of Modular High Temperature Gas-cooled Reactor Loaded with LEU/Thorium Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sonat Sen; Gilles Youinou

    2013-02-01

    Thorium based fuel has been considered as an option to uranium-based fuel, based on considerations of resource utilization (Thorium is more widely available when compared to Uranium). The fertile isotope of Thorium (Th-232) can be converted to fissile isotope U-233 by neutron capture during the operation of a suitable nuclear reactor such as High Temperature Gas-cooled Reactor (HTGR). However, the fertile Thorium needs a fissile supporter to start and maintain the conversion process such as U-235 or Pu-239. This report presents the results of a study that analyzed the thorium utilization in a prismatic HTGR, namely Modular High Temperature Gas-Cooled Reactor (MHTGR) that was designed by General Atomics (GA). The collected for the modeling of this design come from Chapter 4 of MHTGR Preliminary Safety Information Document that GA sent to Department of Energy (DOE) on 1995. Both full core and unit cell models were used to perform this analysis using SCALE 6.1 and Serpent 1.1.18. Because of the long mean free paths (and migration lengths) of neutrons in HTRs, using a unit cell to represent a whole core can be non-trivial. The sizes of these cells were set to match the spectral index between unit cell and full core domains. It was found that for the purposes of this study an adjusted unit cell model is adequate. Discharge isotopics and one-group cross-sections were delivered to the transmutation analysis team. This report provides documentation for these calculations

  7. Use of Distribution Devices for Hydraulic Profiling of Coolant Flow in Core Gas-cooled Reactors

    Directory of Open Access Journals (Sweden)

    A. A. Satin

    2014-01-01

    Full Text Available In setting up a reactor plant for the transportation-power module of the megawatt class an important task is to optimize the path of flow, i.e. providing moderate hydraulic resistance, uniform distribution of the coolant. Significant contribution to the hydraulic losses makes one selected design of the coolant supplies. It is, in particular, hemispherical or semi-elliptical shape of the supply reservoir, which is selected to reduce its mass, resulting in the formation of torusshaped vortex in the inlet manifold, that leads to uneven coolant velocity at the inlet into the core, the flow pulsations, hydraulic losses.To control the flow redistribution in the core according to the level of energy are used the switchgear - deflectors installed in a hemispherical reservoir supplying coolant to the fuel elements (FE of the core of gas-cooled reactor. This design solution has an effect on the structure of the flow, rate in the cooling duct, and the flow resistance of the collector.In this paper we present the results of experiments carried out on the gas dynamic model of coolant paths, deflectors, and core, comprising 55 fuel rod simulators. Numerical simulation of flow in two-parameter model, using the k-ε turbulence model, and the software package ANSYS CFX v14.0 is performed. The paper demonstrates that experimental results are in compliance with calculated ones.The results obtained suggest that the use of switchgear ensures a coolant flow balance directly at the core inlet, thereby providing temperature reduction of fuel rods with a uniform power release in the cross-section. Considered options to find constructive solutions for deflectors give an idea to solve the problem of reducing hydraulic losses in the coolant paths, to decrease pulsation components of flow in the core and length of initial section of flow stabilization.

  8. Flow and Combustion in Advanced Gas Turbine Combustors

    CERN Document Server

    Janicka, Johannes; Schäfer, Michael; Heeger, Christof

    2013-01-01

    With regard to both the environmental sustainability and operating efficiency demands, modern combustion research has to face two main objectives, the optimization of combustion efficiency and the reduction of pollutants. This book reports on the combustion research activities carried out within the Collaborative Research Center (SFB) 568 “Flow and Combustion in Future Gas Turbine Combustion Chambers” funded by the German Research Foundation (DFG). This aimed at designing a completely integrated modeling and numerical simulation of the occurring very complex, coupled and interacting physico-chemical processes, such as turbulent heat and mass transport, single or multi-phase flows phenomena, chemical reactions/combustion and radiation, able to support the development of advanced gas turbine chamber concepts.

  9. Development of advanced hot-gas desulfurization sorbents. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.; Adeyiga, A.A.; Gangwal, S.K.

    1997-10-01

    The objective of this project was to develop hot-gas desulfurization sorbent formulations for relatively lower temperature application, with emphasis on the temperature range from 343--538 C. The candidate sorbents include highly dispersed mixed metal oxides of zinc, iron, copper, cobalt, nickel and molybdenum. The specific objective was to develop suitable sorbents, that would have high and stable surface area and are sufficiently reactive and regenerable at the relatively lower temperatures of interest in this work. Stability of surface area during regeneration was achieved by adding stabilizers. To prevent sulfation, catalyst additives that promote the light-off of the regeneration reaction at lower temperature was considered. Another objective of this study was to develop attrition-resistant advanced hot-gas desulfurization sorbents which show stable and high sulfidation reactivity at 343 to 538 C and regenerability at lower temperatures than leading first generation sorbents.

  10. Thermal Barrier Coatings for Advanced Gas Turbine and Diesel Engines

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    1999-01-01

    Ceramic thermal barrier coatings (TBCS) have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, durability issues of these thermal barrier coatings under high temperature cyclic conditions are still of major concern. The coating failure depends not only on the coating, but also on the ceramic sintering/creep and bond coat oxidation under the operating conditions. Novel test approaches have been established to obtain critical thermomechanical and thermophysical properties of the coating systems under near-realistic transient and steady state temperature and stress gradients encountered in advanced engine systems. This paper presents detailed experimental and modeling results describing processes occurring in the ZrO2-Y2O3 thermal barrier coating systems, thus providing a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  11. Cogeneration power plant concepts using advanced gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Huettenhofer, K.; Lezuo, A. [Siemens Power Generation, Erlangen (Germany)

    2001-07-01

    Cogeneration of heat and power (CHP) is undeniably the environmentally most favourable way of making efficient use of energy in the power generation industry. Cogeneration is also particularly appreciated by political decision makers because of its high yield from primary energy sources, and thus its contribution to the protection of the environment and the conservation of resources. Advanced gas turbines, along with an intelligent power plant design consisting of pre-engineered, modular power plant items, will help cogeneration to play an important role in future energy markets also from an economic point of view. (orig.)

  12. Advanced Combustion Systems for Next Generation Gas Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Joel Haynes; Jonathan Janssen; Craig Russell; Marcus Huffman

    2006-01-01

    Next generation turbine power plants will require high efficiency gas turbines with higher pressure ratios and turbine inlet temperatures than currently available. These increases in gas turbine cycle conditions will tend to increase NOx emissions. As the desire for higher efficiency drives pressure ratios and turbine inlet temperatures ever higher, gas turbines equipped with both lean premixed combustors and selective catalytic reduction after treatment eventually will be unable to meet the new emission goals of sub-3 ppm NOx. New gas turbine combustors are needed with lower emissions than the current state-of-the-art lean premixed combustors. In this program an advanced combustion system for the next generation of gas turbines is being developed with the goal of reducing combustor NOx emissions by 50% below the state-of-the-art. Dry Low NOx (DLN) technology is the current leader in NOx emission technology, guaranteeing 9 ppm NOx emissions for heavy duty F class gas turbines. This development program is directed at exploring advanced concepts which hold promise for meeting the low emissions targets. The trapped vortex combustor is an advanced concept in combustor design. It has been studied widely for aircraft engine applications because it has demonstrated the ability to maintain a stable flame over a wide range of fuel flow rates. Additionally, it has shown significantly lower NOx emission than a typical aircraft engine combustor and with low CO at the same time. The rapid CO burnout and low NOx production of this combustor made it a strong candidate for investigation. Incremental improvements to the DLN technology have not brought the dramatic improvements that are targeted in this program. A revolutionary combustor design is being explored because it captures many of the critical features needed to significantly reduce emissions. Experimental measurements of the combustor performance at atmospheric conditions were completed in the first phase of the program

  13. On0Line Fuel Failure Monitor for Fuel Testing and Monitoring of Gas Cooled Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Ayman I. Hawari; Mohamed A. Bourham

    2010-04-22

    IVery High Temperature Reactors (VHTR) utilize the TRISO microsphere as the fundamental fuel unit in the core. The TRISO microsphere (~ 1- mm diameter) is composed of a UO2 kernel surrounded by a porous pyrolytic graphite buffer, an inner pyrolytic graphite layer, a silicon carbide (SiC) coating, and an outer pyrolytic graphite layer. The U-235 enrichment of the fuel is expected to range from 4% – 10% (higher enrichments are also being considered). The layer/coating system that surrounds the UO2 kernel acts as the containment and main barrier against the environmental release of radioactivity. To understand better the behavior of this fuel under in-core conditions (e.g., high temperature, intense fast neutron flux, etc.), the US Department of Energy (DOE) is launching a fuel testing program that will take place at the Advanced Test Reactor (ATR) located at Idaho National Laboratory (INL). During this project North Carolina State University (NCSU) researchers will collaborate with INL staff for establishing an optimized system for fuel monitoring for the ATR tests. In addition, it is expected that the developed system and methods will be of general use for fuel failure monitoring in gas cooled VHTRs.

  14. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    1999-04-26

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3% of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to development of optimized low-cost zinc-oxide-based sorbents for Sierra-Pacific. The sorbent surface were modified to prevent

  15. Exergy, Economic and Environmental Analyses of Gas Turbine Inlet Air Cooling with a Heat Pump Using a Novel System Configuration

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Majdi Yazdi

    2015-10-01

    Full Text Available Gas turbines incur a loss of output power during hot seasons due to high ambient air temperatures, and input air cooling systems are often used to partly offset this problem. Here, results are reported for an investigation of the utilization of a heat pump to cool the inlet air of a gas turbine compressor. The analyses are carried out for two climates: the city of Yazd, Iran, which has a hot, arid climate, and Tehran, Iran, which has a temperate climate. The heat pump input power is obtained from the gas turbine. The following parameters are determined, with and without the heat pump: net output power, first and second law efficiencies, quantities and costs of environmental pollutants, entropy generation and power generation. The results suggest that, by using the air-inlet cooling system, the mean output power increases during hot seasons by 11.5% and 10% for Yazd and Tehran, respectively, and that the costs of power generation (including pollution costs decrease by 11% and 10% for Yazd and Tehran, respectively. Also, the rate of generation of pollutants such as NOx and CO decrease by about 10% for Yazd and 35% for Tehran, while the average annual entropy generation rate increases by 9% for Yazd and 7% for Tehran, through air-inlet cooling. The average increase of the system first law efficiency is 2% and of the system second law efficiency is 1.5% with the inlet-air cooling system.

  16. Not Dead Yet: Cool Circumgalactic Gas in the Halos of Early Type Galaxies

    CERN Document Server

    Thom, Christopher; Werk, Jessica K; Prochaska, J Xavier; Oppenheimer, Benjamin D; Peeples, Molly S; Tripp, Todd M; Katz, Neal S; O'Meara, John M; Ford, Amanda Brady; Dave, Romeel; Sembach, Kenneth R; Weinberg, David H

    2012-01-01

    We report new observations of circumgalactic gas in the halos of early type galaxies obtained by the COS-Halos Survey with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. We find that detections of HI surrounding early type galaxies are typically as common and strong as around star-forming galaxies, implying that the total mass of circumgalactic material is comparable in the two populations. For early type galaxies, the covering fraction for HI absorption above 10^16 cm^2 is ~40-50% within ~150 kpc. Line widths and kinematics of the detected material show it to be cold (T ~< 10^5 K) in comparison to the virial temperature of the host halos. The implied masses of cool, photoionized CGM baryons may be up to 10^9 --- 10^11 Msun. Contrary to some theoretical expectations, strong halo HI absorbers do not disappear as part of the quenching of star-formation. Even passive galaxies retain significant reservoirs of halo baryons which could replenish the interstellar gas reservoir and eventually ...

  17. Thermochemical Analysis of Gas-Cooled Reactor Fuels Containing Am and Pu Oxides

    Energy Technology Data Exchange (ETDEWEB)

    Lindemer, T.B.

    2002-09-05

    Literature values and estimated data for the thermodynamics of the actinide oxides and fission products are applied to explain the chemical behavior in gas-cooled-reactor fuels. Emphasis is placed on the Am-O-C and Pu-O-C systems and the data are used to plot the oxygen chemical potential versus temperature of solid-solid and solid-gas equilibria. These results help explain observations of vaporization in Am oxides, nitrides, and carbides and provide guidance for the ceramic processing of the fuels. The thermodynamic analysis is then extended to the fission product systems and the Si-C-O system. Existing data on oxygen release (primarily as CO) as a function of burnup in the thoria-urania fuel system is reviewed and compared to values calculated from thermodynamic data. The calculations of oxygen release are then extended to the plutonia and americia fuels. Use of ZrC not only as a particle coating that may be more resistant to corrosion by Pd and other noble-metal fission products, but also as a means to getter oxygen released by fission is discussed.

  18. Measurement of the orientation of buffer-gas-cooled, electrostatically-guided ammonia molecules

    Science.gov (United States)

    Steer, Edward W.; Petralia, Lorenzo S.; Western, Colin M.; Heazlewood, Brianna R.; Softley, Timothy P.

    2017-02-01

    The extent to which the spatial orientation of internally and translationally cold ammonia molecules can be controlled as molecules pass out of a quadrupole guide and through different electric field regions is examined. Ammonia molecules are collisionally cooled in a buffer gas cell, and are subsequently guided by a three-bend electrostatic quadrupole into a detection chamber. The orientation of ammonia molecules is probed using (2 + 1) resonance-enhanced multiphoton ionisation (REMPI), with the laser polarisation axis aligned both parallel and perpendicular to the time-of-flight axis. Even with the presence of a near-zero field region, the ammonia REMPI spectra indicate some retention of orientation. Monte Carlo simulations propagating the time-dependent Schrödinger equation in a full basis set including the hyperfine interaction enable the orientation of ammonia molecules to be calculated - with respect to both the local field direction and a space-fixed axis - as the molecules pass through different electric field regions. The simulations indicate that the orientation of ∼95% of ammonia molecules in JK =11 could be achieved with the application of a small bias voltage (17 V) to the mesh separating the quadrupole and detection regions. Following the recent combination of the buffer gas cell and quadrupole guide apparatus with a linear Paul ion trap, this result could enable one to examine the influence of molecular orientation on ion-molecule reaction dynamics and kinetics.

  19. Blue-sky bifurcation of ion energies and the limits of neutral-gas sympathetic cooling of trapped ions

    Science.gov (United States)

    Schowalter, Steven J.; Dunning, Alexander J.; Chen, Kuang; Puri, Prateek; Schneider, Christian; Hudson, Eric R.

    2016-01-01

    Sympathetic cooling of trapped ions through collisions with neutral buffer gases is critical to a variety of modern scientific fields, including fundamental chemistry, mass spectrometry, nuclear and particle physics, and atomic and molecular physics. Despite its widespread use over four decades, there remain open questions regarding its fundamental limitations. To probe these limits, here we examine the steady-state evolution of up to 10 barium ions immersed in a gas of three-million laser-cooled calcium atoms. We observe and explain the emergence of nonequilibrium behaviour as evidenced by bifurcations in the ion steady-state temperature, parameterized by ion number. We show that this behaviour leads to the limitations in creating and maintaining translationally cold samples of trapped ions using neutral-gas sympathetic cooling. These results may provide a route to studying non-equilibrium thermodynamics at the atomic level. PMID:27511602

  20. Blue-sky bifurcation of ion energies and the limits of neutral-gas sympathetic cooling of trapped ions

    CERN Document Server

    Schowalter, Steven J; Chen, Kuang; Puri, Prateek; Schneider, Christian; Hudson, Eric R

    2016-01-01

    Sympathetic cooling of trapped ions through collisions with neutral buffer gases is critical to a variety of modern scientific fields, including fundamental chemistry, mass spectrometry, nuclear and particle physics, and atomic and molecular physics. Despite its widespread use over four decades, there remain open questions regarding its fundamental limitations. To probe these limits, here we examine the steady-state evolution of up to ten barium ions immersed in a gas of three-million laser-cooled calcium atoms. We observe and explain the emergence of nonequilibrium behavior as evidenced by bifurcations in the ion steady-state temperature, parameterized by ion number. We show that this behavior leads to limitations in creating and maintaining translationally cold samples of trapped ions using neutral-gas sympathetic cooling. These results may provide a route to studying nonequilibrium thermodynamics.

  1. Blue-sky bifurcation of ion energies and the limits of neutral-gas sympathetic cooling of trapped ions

    Science.gov (United States)

    Schowalter, Steven J.; Dunning, Alexander J.; Chen, Kuang; Puri, Prateek; Schneider, Christian; Hudson, Eric R.

    2016-08-01

    Sympathetic cooling of trapped ions through collisions with neutral buffer gases is critical to a variety of modern scientific fields, including fundamental chemistry, mass spectrometry, nuclear and particle physics, and atomic and molecular physics. Despite its widespread use over four decades, there remain open questions regarding its fundamental limitations. To probe these limits, here we examine the steady-state evolution of up to 10 barium ions immersed in a gas of three-million laser-cooled calcium atoms. We observe and explain the emergence of nonequilibrium behaviour as evidenced by bifurcations in the ion steady-state temperature, parameterized by ion number. We show that this behaviour leads to the limitations in creating and maintaining translationally cold samples of trapped ions using neutral-gas sympathetic cooling. These results may provide a route to studying non-equilibrium thermodynamics at the atomic level.

  2. Nuclear Engineering Computer Modules, Thermal-Hydraulics, TH-3: High Temperature Gas Cooled Reactor Thermal-Hydraulics.

    Science.gov (United States)

    Reihman, Thomas C.

    This learning module is concerned with the temperature field, the heat transfer rates, and the coolant pressure drop in typical high temperature gas-cooled reactor (HTGR) fuel assemblies. As in all of the modules of this series, emphasis is placed on developing the theory and demonstrating its use with a simplified model. The heart of the module…

  3. Flow Integrating Section for a Gas Turbine Engine in Which Turbine Blades are Cooled by Full Compressor Flow

    Energy Technology Data Exchange (ETDEWEB)

    Steward, W. Gene

    1999-11-14

    Routing of full compressor flow through hollow turbine blades achieves unusually effective blade cooling and allows a significant increase in turbine inlet gas temperature and, hence, engine efficiency. The invention, ''flow integrating section'' alleviates the turbine dissipation of kinetic energy of air jets leaving the hollow blades as they enter the compressor diffuser.

  4. Development of advanced hot-gas desulfurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Jothimurugesan, K.

    2000-04-17

    Advanced integrated gasification combined cycle (IGCC) power plants nearing completion, such as Sierra-Pacific, employ a circulating fluidized-bed (transport) reactor hot-gas desulfurization (HGD) process that uses 70-180 {micro}m average particle size (aps) zinc-based mixed-metal oxide sorbent for removing H{sub 2}S from coal gas down to less than 20 ppmv. The sorbent undergoes cycles of absorption (sulfidation) and air regeneration. The key barrier issues associated with a fluidized-bed HGD process are chemical degradation, physical attrition, high regeneration light-off (initiation) temperature, and high cost of the sorbent. Another inherent complication in all air-regeneration-based HGD processes is the disposal of the problematic dilute SO{sub 2} containing regeneration tail-gas. Direct Sulfur Recovery Process (DSRP), a leading first generation technology, efficiently reduces this SO{sub 2} to desirable elemental sulfur, but requires the use of 1-3 % of the coal gas, thus resulting in an energy penalty to the plant. Advanced second-generation processes are under development that can reduce this energy penalty by modifying the sorbent so that it could be directly regenerated to elemental sulfur. The objective of this research is to support the near and long term DOE efforts to commercialize the IGCC-HGD process technology. Specifically we aim to develop: optimized low-cost sorbent materials with 70-80 {micro}m average aps meeting all Sierra specs; attrition resistant sorbents with 170 {micro}m aps that allow greater flexibility in the choice of the type of fluidized-bed reactor e.g. they allow increased throughput in a bubbling-bed reactor; and modified fluidizable sorbent materials that can be regenerated to produce elemental sulfur directly with minimal or no use of coal gas. The effort during the reporting period has been devoted to testing the FHR-32 sorbent. FHR-32 sorbent was tested for 50 cycles of sulfidation in a laboratory scale reactor.

  5. DEVELOPMENT OF ADVANCED HOT-GAS DESULFURIZATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    K. Jothimurugesan; Santosh K. Gangwal

    2000-12-01

    The techniques employed in this project have successfully demonstrated the feasibility of preparing sorbents that achieve greater than 99% H{sub 2}S removal at temperatures 480 C and that retain their activity over 50 cycles. Fundamental understanding of phenomena leading to chemical deactivation and high regeneration light-off temperature has enabled us to successfully prepare and scale up a FHR-32 sorbent that showed no loss in reactivity and capacity over 50 cycles. This sorbent removed H{sub 2}S below 80 ppmv and lighted-off nicely at 480 C during regeneration. Overall the test is a success with potential for an optimized FHR-32 to be a candidate for Sierra-Pacific. An advanced attrition resistant hot-gas desulfurization sorbent that can eliminate the problematic SO{sub 2} tail gas and yield elemental sulfur directly has been developed. Attrition resistant Zn-Fe sorbent (AHI-2) formulations have been prepared that can remove H{sub 2}S to below 20 ppmv from coal gas and can be regenerated using SO{sub 2} to produce elemental sulfur.

  6. Natural Gas for Advanced Dual-Fuel Combustion Strategies

    Science.gov (United States)

    Walker, Nicholas Ryan

    Natural gas fuels represent the next evolution of low-carbon energy feedstocks powering human activity worldwide. The internal combustion engine, the energy conversion device widely used by society for more than one century, is capable of utilizing advanced combustion strategies in pursuit of ultra-high efficiency and ultra-low emissions. Yet many emerging advanced combustion strategies depend upon traditional petroleum-based fuels for their operation. In this research the use of natural gas, namely methane, is applied to both conventional and advanced dual-fuel combustion strategies. In the first part of this work both computational and experimental studies are undertaken to examine the viability of utilizing methane as the premixed low reactivity fuel in reactivity controlled compression ignition, a leading advanced dual-fuel combustion strategy. As a result, methane is shown to be capable of significantly extending the load limits for dual-fuel reactivity controlled compression ignition in both light- and heavy-duty engines. In the second part of this work heavy-duty single-cylinder engine experiments are performed to research the performance of both conventional dual-fuel (diesel pilot ignition) and advanced dual-fuel (reactivity controlled compression ignition) combustion strategies using methane as the premixed low reactivity fuel. Both strategies are strongly influenced by equivalence ratio; diesel pilot ignition offers best performance at higher equivalence ratios and higher premixed methane ratios, whereas reactivity controlled compression ignition offers superior performance at lower equivalence ratios and lower premixed methane ratios. In the third part of this work experiments are performed in order to determine the dominant mode of heat release for both dual-fuel combustion strategies. By studying the dual-fuel homogeneous charge compression ignition and single-fuel spark ignition, strategies representative of autoignition and flame propagation

  7. Method and apparatus maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Farthing, William Earl (Pinson, AL); Felix, Larry Gordon (Pelham, AL); Snyder, Todd Robert (Birmingham, AL)

    2009-12-15

    An apparatus and method for diluting and cooling that is extracted from high temperature and/or high pressure industrial processes. Through a feedback process, a specialized, CFD-modeled dilution cooler is employed along with real-time estimations of the point at which condensation will occur within the dilution cooler to define a level of dilution and diluted gas temperature that results in a gas that can be conveyed to standard gas analyzers that contains no condensed hydrocarbon compounds or condensed moisture.

  8. Cold molecular gas in the Perseus cluster core - Association with X-ray cavity, Halpha filaments and cooling flow -

    CERN Document Server

    Salomé, P; Crawford, C; Edge, A C; Erlund, M; Fabian, A C; Hatch, N A; Johnstone, R M; Sanders, J S; Wilman, R J

    2006-01-01

    Cold molecular gas has been recently detected in several cooling flow clusters of galaxies where huge optical nebulosities often stand. These optical filaments are tightly linked to the cooling flow and to the related phenomena, like the rising bubbles of relativistic plasma, fed by the radio jets. We present here a map in the CO(2-1) rotational line of the cold molecular gas associated with some Halpha filaments surrounding the central galaxy of the Perseus cluster: NGC 1275. The map, extending to about 50 kpc (135 arcsec) from the center of the galaxy, has been made with the 18-receiver array HERA, at the focus of the IRAM 30m telescope. Although most of the cold gas is concentrated to the center of the galaxy, the CO emission is also clearly associated to the extended filaments conspicuous in ionised gas and could trace a possible reservoir fueling the star formation there. Some of the CO emission is also found where the X-ray gas could cool down more efficiently: at the rims of the central X-ray cavity (w...

  9. High-Temperature Gas-Cooled Reactor Technology Development Program: Annual progress report for period ending December 31, 1987

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.E.,Jr.; Kasten, P.R.; Rittenhouse, P.L.; Sanders, J.P.

    1989-03-01

    The High-Temperature Gas-Cooled Reactor (HTGR) Program being carried out under the US Department of Energy (DOE) continues to emphasize the development of modular high-temperature gas-cooled reactors (MHTGRs) possessing a high degree of inherent safety. The emphasis at this time is to develop the preliminary design of the reference MHTGR and to develop the associated technology base and licensing infrastructure in support of future reactor deployment. A longer-term objective is to realize the full high-temperature potential of HTGRs in gas turbine and high-temperature, process-heat applications. This document summarizes the activities of the HTGR Technology Development Program for the period ending December 31, 1987.

  10. Gas cooling in semi-analytic models and smoothed particle hydrodynamics simulations: are results consistent?

    Science.gov (United States)

    Saro, A.; De Lucia, G.; Borgani, S.; Dolag, K.

    2010-08-01

    We present a detailed comparison between the galaxy populations within a massive cluster, as predicted by hydrodynamical smoothed particle hydrodynamics (SPH) simulations and by a semi-analytic model (SAM) of galaxy formation. Both models include gas cooling and a simple prescription of star formation, which consists in transforming instantaneously any cold gas available into stars, while neglecting any source of energy feedback. This simplified comparison is thus not meant to be compared with observational data, but is aimed at understanding the level of agreement, at the stripped-down level considered, between two techniques that are widely used to model galaxy formation in a cosmological framework and which present complementary advantages and disadvantages. We find that, in general, galaxy populations from SAMs and SPH have similar statistical properties, in agreement with previous studies. However, when comparing galaxies on an object-by-object basis, we find a number of interesting differences: (i) the star formation histories of the brightest cluster galaxies (BCGs) from SAM and SPH models differ significantly, with the SPH BCG exhibiting a lower level of star formation activity at low redshift, and a more intense and shorter initial burst of star formation with respect to its SAM counterpart; (ii) while all stars associated with the BCG were formed in its progenitors in the SAM used here, this holds true only for half of the final BCG stellar mass in the SPH simulation, the remaining half being contributed by tidal stripping of stars from the diffuse stellar component associated with galaxies accreted on the cluster halo; (iii) SPH satellites can lose up to 90 per cent of their stellar mass at the time of accretion, due to tidal stripping, a process not included in the SAM used in this paper; (iv) in the SPH simulation, significant cooling occurs on the most massive satellite galaxies and this lasts for up to 1 Gyr after accretion. This physical process is

  11. Evaluation of Thermoelectric Properties of Bite Alloys for the Optimization of Gas-Cooled Peltier Current Lead

    Science.gov (United States)

    Fujii, T.; Fukuda, S.; Kawahara, T.; Emoto, M.; Sugino, M.; Sun, J.; Hamabe, M.; Watanabe, H.; Yamaguchi, S.

    2010-04-01

    A direct current superconducting power transmission (DC-SCPT) test facility with 20-meter power cable has been developed in Chubu University. Heat leakage through current leads dominates in case of short-distance DC-SCPT. To solve this problem, we have developed special Peltier current lead (PCL) with bismuth telluride (BiTe) alloy is used as a Peltier material, and have studied a gas-cooled PCL as a novel type current lead for higher reduction of the heat leakage. In order to achieve high efficiency, highest thermoelectric figure of merit material is important to be used especially at low temperature conditions. In our work we measured the thermoelectric properties of BiTe samples, and optimized geometry of PCL by the numerical calculations. It was fount that the heat leakages through PCL and gas-cooled PCL are reduced to 55% and to 36% of the conventional copper current lead (CCL) at the self-cooling condition, correspondingly. PCL can reduce the total electric power consumption of the whole system. We also discuss the heat exchange ratio for the gas-cooled PCL, and extend this approach for further reduction of the heat leakage.

  12. Comparative analysis of steady state heat transfer in a TBC and functionally graded air cooled gas turbine blade

    Indian Academy of Sciences (India)

    Nilanjan Coomar; Ravikiran Kadoli

    2010-02-01

    Internal cooling passages and thermal barrier coatings (TBCs) are presently used to control metal temperatures in gas turbine blades. Functionally graded materials (FGMs), which are typically mixtures of ceramic and metal, have been proposed for use in turbine blades because they possess smooth property gradients thereby rendering them more durable under thermal loads. In the present work, a functionally graded model of an air-cooled turbine blade with airfoil geometry conforming to the NACA0012 is developed which is then used in a finite element algorithm to obtain a non-linear steady state solution to the heat equation for the blade under convection and radiation boundary conditions. The effects of external gas temperature, coolant temperature, surface emissivity changes and different average ceramic/metal content of the blade on the temperature distributions are examined. Simulations are also carried out to compare cooling effectiveness of functionally graded blades with that of blades having TBC. The results highlight the effect of including radiation in the simulation and also indicate that external gas temperature influences the blade heat transfer more strongly. It is also seen that graded blades with about 70% ceramic content can deliver better cooling effectiveness than conventional blades with TBC.

  13. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling Systems for the Advanced Extravehicular Mobility Unit Portable Life Support System

    Science.gov (United States)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean.; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Petty, Brian

    2014-01-01

    Spacesuit Water Membrane Evaporator - Baseline heat rejection technology for the Portable Life Support System of the Advanced EMU center dot Replaces sublimator in the current EMU center dot Contamination insensitive center dot Can work with Lithium Chloride Absorber Radiator in Spacesuit Evaporator Absorber Radiator (SEAR) to reject heat and reuse evaporated water The Spacesuit Water Membrane Evaporator (SWME) is being developed to replace the sublimator for future generation spacesuits. Water in LCVG absorbs body heat while circulating center dot Warm water pumped through SWME center dot SWME evaporates water vapor, while maintaining liquid water - Cools water center dot Cooled water is then recirculated through LCVG. center dot LCVG water lost due to evaporation (cooling) is replaced from feedwater The Independent TCV Manifold reduces design complexity and manufacturing difficulty of the SWME End Cap. center dot The offset motor for the new BPV reduces the volume profile of the SWME by laying the motor flat on the End Cap alongside the TCV.

  14. Environmental benefits of advanced oil and gas exploration and production technology

    Energy Technology Data Exchange (ETDEWEB)

    None

    1999-10-01

    THROUGHOUT THE OIL AND GAS LIFE CYCLE, THE INDUSTRY HAS APPLIED AN ARRAY OF ADVANCED TECHNOLOGIES TO IMPROVE EFFICIENCY, PRODUCTIVITY, AND ENVIRONMENTAL PERFORMANCE. THIS REPORT FOCUSES SPECIFICALLY ON ADVANCES IN EXPLORATION AND PRODUCTION (E&P) OPERATIONS.

  15. A 50-100 kWe gas-cooled reactor for use on Mars.

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Curtis D. (.)

    2006-04-01

    In the space exploration field there is a general consensus that nuclear reactor powered systems will be extremely desirable for future missions to the outer solar system. Solar systems suffer from the decreasing intensity of solar radiation and relatively low power density. Radioisotope Thermoelectric Generators are limited to generating a few kilowatts electric (kWe). Chemical systems are short-lived due to prodigious fuel use. A well designed 50-100 kWe nuclear reactor power system would provide sufficient power for a variety of long term missions. This thesis will present basic work done on a 50-100 kWe reactor power system that has a reasonable lifespan and would function in an extraterrestrial environment. The system will use a Gas-Cooled Reactor that is directly coupled to a Closed Brayton Cycle (GCR-CBC) power system. Also included will be some variations on the primary design and their effects on the characteristics of the primary design. This thesis also presents a variety of neutronics related calculations, an examination of the reactor's thermal characteristics, feasibility for use in an extraterrestrial environment, and the reactor's safety characteristics in several accident scenarios. While there has been past work for space reactors, the challenges introduced by thin atmospheres like those on Mars have rarely been considered.

  16. Effect of Target Configuration on the Neutronic Performance of the Gas-Cooled ADS

    CERN Document Server

    Biss, K; Shetty, N; Nabbi, R

    2013-01-01

    With the utilization of nuclear energy transuranic elements like Pu, Am and Cm are produced causing high, long term radioactivity and radio toxicity, respectively. To reduce the radiological impact on the environment and to the repository Partitioning and Transmutation is considered as an efficient way. In this respect comprehensive research works are performed at different research institutes worldwide. The results show that the transmutation of TRU is achieved with fast neutrons due to the higher fission probability. Based on Accelerator Driven Systems (ADS) those neutrons are used in a particular system, in which mainly liquid metal eutectic (lead bismuth) is used as coolant. The neutronic performance of an ADS system based on gas cooling was studied in this work by using the simulation tool MCNPX. The usage of the Monte-Carlo method in MCNPX allows the simulation of the physical processes in a 3D-model of the core. In dependence of the spallation target material and design several parameters like the mult...

  17. Validation of SCALE for High Temperature Gas-Cooled Reactors Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [ORNL; Ilas, Dan [ORNL; Kelly, Ryan P [ORNL; Sunny, Eva E [ORNL

    2012-08-01

    This report documents verification and validation studies carried out to assess the performance of the SCALE code system methods and nuclear data for modeling and analysis of High Temperature Gas-Cooled Reactor (HTGR) configurations. Validation data were available from the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhE Handbook), prepared by the International Reactor Physics Experiment Evaluation Project, for two different HTGR designs: prismatic and pebble bed. SCALE models have been developed for HTTR, a prismatic fuel design reactor operated in Japan and HTR-10, a pebble bed reactor operated in China. The models were based on benchmark specifications included in the 2009, 2010, and 2011 releases of the IRPhE Handbook. SCALE models for the HTR-PROTEUS pebble bed configuration at the PROTEUS critical facility in Switzerland have also been developed, based on benchmark specifications included in a 2009 IRPhE draft benchmark. The development of the SCALE models has involved a series of investigations to identify particular issues associated with modeling the physics of HTGRs and to understand and quantify the effect of particular modeling assumptions on calculation-to-experiment comparisons.

  18. CFD Analysis of the Fuel Temperature in High Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    In, W. K.; Chun, T. H.; Lee, W. J.; Chang, J. H. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    High temperature gas-cooled reactors (HTGR) have received a renewed interest as potential sources for future energy needs, particularly for a hydrogen production. Among the HTGRs, the pebble bed reactor (PBR) and a prismatic modular reactor (PMR) are considered as the nuclear heat source in Korea's nuclear hydrogen development and demonstration project. PBR uses coated fuel particles embedded in spherical graphite fuel pebbles. The fuel pebbles flow down through the core during an operation. PMR uses graphite fuel blocks which contain cylindrical fuel compacts consisting of the fuel particles. The fuel blocks also contain coolant passages and locations for absorber and control material. The maximum fuel temperature in the core hot spot is one of the important design parameters for both PBR and PMR. The objective of this study is to predict the fuel temperature distributions in PBR and PMR using a computational fluid dynamics(CFD) code, CFX-5. The reference reactor designs used in this analysis are PBMR400 and GT-MHR600.

  19. Gas-cooled fast reactor fuel-cost assessment. Final report, October 1978-September 1979

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, M.L.

    1979-01-01

    This program, contracted to provide a Gas Cooled Fast Reactor (GCFR) fuel assembly fabrication cost assessment, comprised the following basic activities: establish agreement on the ground rules for cost assessment, prepare a fuel factory flow sheet, and prepare a cost assessment for fuel assembly fabrication. Two factory sizes, 250 and 25 MTHM/year, were considered for fuel assembly fabrication cost assessment. The work on this program involved utilizing GE LMFBR cost assessment and fuel factory studies experience to provide a cost assessment of GCFR fuel assembly fabrication. The recent impact of highly sensitive safety and safeguards environment policies on fuel factory containment, safety, quality assurance and safeguards costs are significantly higher than might have been expected just a few years ago. Fuel assembly fabrication costs are significant because they represent an estimated 30 to 60% of the total fuel cycle costs. In light of the relative high cost of fabrication, changes in the core and assembly design may be necessary in order to enhance the overall fuel cycle economics. Fabrication costs are based on similar operations and experience used in other fuel cycle studies. Because of extrapolation of present technology (e.g., remote fuel fabrication versus present contact fabrication) and regulatory requirements, conservative cost estimates were made.

  20. Properties of the homogeneous cooling state of a gas of inelastic rough particles

    Science.gov (United States)

    Reyes, Francisco Vega; Santos, Andres; Kremer, Gilberto M.

    2014-12-01

    In this work we address the question of whether a low-density system composed of identical rough particles may reach hydrodynamic states (also called normal states), even if energy is not conserved in particle collisions. As a way to measure the ability of the system to present a hydrodynamic behavior, we focus on the so-called homogeneous cooling state of the granular gas and look at the corresponding relaxation time as a function of inelasticity and roughness. We report computer simulation results of the sixth- and eighth-order cumulants of the particle velocity distribution function and study the influence of roughness on their relaxation times and asymptotic values. This extends the results of a previous work [Phys. Rev. E 89, 020202(R) (2014], where lower-order cumulants were measured. Our results confirm that the relaxation times are not necessarily longer for stronger inelasticities. This implies that dissipation by itself does not preclude hydrodynamics. It is also observed that the cumulants associated with the angular velocity distribution may reach very high values in a certain region of (small) roughness and that these maxima coincide with small orientational correlation points.

  1. Procedure of Active Residual Heat Removal after Emergency Shutdown of High-Temperature-Gas-Cooled Reactor

    Directory of Open Access Journals (Sweden)

    Xingtuan Yang

    2014-01-01

    Full Text Available After emergency shutdown of high-temperature-gas-cooled reactor, the residual heat of the reactor core should be removed. As the natural circulation process spends too long period of time to be utilized, an active residual heat removal procedure is needed, which makes use of steam generator and start-up loop. During this procedure, the structure of steam generator may suffer cold/heat shock because of the sudden load of coolant or hot helium at the first few minutes. Transient analysis was carried out based on a one-dimensional mathematical model for steam generator and steam pipe of start-up loop to achieve safety and reliability. The results show that steam generator should be discharged and precooled; otherwise, boiling will arise and introduce a cold shock to the boiling tubes and tube sheet when coolant began to circulate prior to the helium. Additionally, in avoiding heat shock caused by the sudden load of helium, the helium circulation should be restricted to start with an extreme low flow rate; meanwhile, the coolant of steam generator (water should have flow rate as large as possible. Finally, a four-step procedure with precooling process of steam generator was recommended; sensitive study for the main parameters was conducted.

  2. A Compact Gas-Cooled Fast Reactor with an Ultra-Long Fuel Cycle

    Directory of Open Access Journals (Sweden)

    Hangbok Choi

    2013-01-01

    Full Text Available In an attempt to allow nuclear power to reach its full economic potential, General Atomics is developing the Energy Multiplier Module (EM2, which is a compact gas-cooled fast reactor (GFR. The EM2 augments its fissile fuel load with fertile materials to enhance an ultra-long fuel cycle based on a “convert-and-burn” core design which converts fertile material to fissile fuel and burns it in situ over a 30-year core life without fuel supplementation or shuffling. A series of reactor physics trade studies were conducted and a baseline core was developed under the specific physics design requirements of the long-life small reactor. The EM2 core performance was assessed for operation time, fuel burnup, excess reactivity, peak power density, uranium utilization, etc., and it was confirmed that an ultra-long fuel cycle core is feasible if the conversion is enough to produce fissile material and maintain criticality, the amount of matrix material is minimized not to soften the neutron spectrum, and the reactor core size is optimized to minimize the neutron loss. This study has shown the feasibility, from the reactor physics standpoint, of a compact GFR that can meet the objectives of ultra-long fuel cycle, factory-fabrication, and excellent fuel utilization.

  3. HYBRID SULFUR CYCLE FLOWSHEETS FOR HYDROGEN PRODUCTION USING HIGH-TEMPERATURE GAS-COOLED REACTORS

    Energy Technology Data Exchange (ETDEWEB)

    Gorensek, M.

    2011-07-06

    Two hybrid sulfur (HyS) cycle process flowsheets intended for use with high-temperature gas-cooled reactors (HTGRs) are presented. The flowsheets were developed for the Next Generation Nuclear Plant (NGNP) program, and couple a proton exchange membrane (PEM) electrolyzer for the SO2-depolarized electrolysis step with a silicon carbide bayonet reactor for the high-temperature decomposition step. One presumes an HTGR reactor outlet temperature (ROT) of 950 C, the other 750 C. Performance was improved (over earlier flowsheets) by assuming that use of a more acid-tolerant PEM, like acid-doped poly[2,2'-(m-phenylene)-5,5'-bibenzimidazole] (PBI), instead of Nafion{reg_sign}, would allow higher anolyte acid concentrations. Lower ROT was accommodated by adding a direct contact exchange/quench column upstream from the bayonet reactor and dropping the decomposition pressure. Aspen Plus was used to develop material and energy balances. A net thermal efficiency of 44.0% to 47.6%, higher heating value basis is projected for the 950 C case, dropping to 39.9% for the 750 C case.

  4. THR-TH: a high-temperature gas-cooled nuclear reactor core thermal hydraulics code

    Energy Technology Data Exchange (ETDEWEB)

    Vondy, D.R.

    1984-07-01

    The ORNL version of PEBBLE, the (RZ) pebble bed thermal hydraulics code, has been extended for application to a prismatic gas cooled reactor core. The supplemental treatment is of one-dimensional coolant flow in up to a three-dimensional core description. Power density data from a neutronics and exposure calculation are used as the basic information for the thermal hydraulics calculation of heat removal. Two-dimensional neutronics results may be expanded for a three-dimensional hydraulics calculation. The geometric description for the hydraulics problem is the same as used by the neutronics code. A two-dimensional thermal cell model is used to predict temperatures in the fuel channel. The capability is available in the local BOLD VENTURE computation system for reactor core analysis with capability to account for the effect of temperature feedback by nuclear cross section correlation. Some enhancements have also been added to the original code to add pebble bed modeling flexibility and to generate useful auxiliary results. For example, an estimate is made of the distribution of fuel temperatures based on average and extreme conditions regularly calculated at a number of locations.

  5. Gas Cooled Fast Reactor Research and Development in the European Union

    Directory of Open Access Journals (Sweden)

    Richard Stainsby

    2009-01-01

    Full Text Available Gas-cooled fast reactor (GFR research is directed towards fulfilling the ambitious goals of Generation IV (Gen IV, that is, to develop a safe, sustainable, reliable, proliferation-resistant and economic nuclear energy system. The research is directed towards developing the GFR as an economic electricity generator, with good safety and sustainability characteristics. Fast reactors maximise the usefulness of uranium resources by breeding plutonium and can contribute to minimising both the quantity and radiotoxicity nuclear waste by actinide transmutation in a closed fuel cycle. Transmutation is particularly effective in the GFR core owing to its inherently hard neutron spectrum. Further, GFR is suitable for hydrogen production and process heat applications through its high core outlet temperature. As such GFR can inherit the non-electricity applications that will be developed for thermal high temperature reactors in a sustainable manner. The Euratom organisation provides a route by which researchers in all European states, and other non-European affiliates, can contribute to the Gen IV GFR system. This paper summarises the achievements of Euratom's research into the GFR system, starting with the 5th Framework programme (FP5 GCFR project in 2000, through FP6 (2005 to 2009 and looking ahead to the proposed activities within the 7th Framework Programme (FP7.

  6. Recent Development in Turbine Blade Film Cooling

    Directory of Open Access Journals (Sweden)

    Je-Chin Han

    2001-01-01

    Full Text Available Gas turbines are extensively used for aircraft propulsion, land-based power generation, and industrial applications. Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperature (RIT. The current RIT level in advanced gas turbines is far above the .melting point of the blade material. Therefore, along with high temperature material development, a sophisticated cooling scheme must be developed for continuous safe operation of gas turbines with high performance. Gas turbine blades are cooled internally and externally. This paper focuses on external blade cooling or so-called film cooling. In film cooling, relatively cool air is injected from the inside of the blade to the outside surface which forms a protective layer between the blade surface and hot gas streams. Performance of film cooling primarily depends on the coolant to mainstream pressure ratio, temperature ratio, and film hole location and geometry under representative engine flow conditions. In the past number of years there has been considerable progress in turbine film cooling research and this paper is limited to review a few selected publications to reflect recent development in turbine blade film cooling.

  7. Optimization of intermediate cooling and intermediate heating in the gas turbine process; Optimierung der Zwischenkuehlung und der Zwischenerhitzung beim Gasturbinenprozess

    Energy Technology Data Exchange (ETDEWEB)

    Woerrlein, K.

    1998-07-01

    The author investigated how the thermal efficiency of the gas turbine process can be improved by intermediate cooling, intermediate heating, or combined intermediate cooling and heating. The focus was on the pressure ratios of low-pressure compressors and high-pressure turbines. The numeric calculations were carried out using real gas characteristics. The findings suggest that intermediate coling inside the compressor has much more influence on the thermal efficiency than intermediate heating inside the turbine. However, the latter is advantageous in the case of gas turbines for combined cycle operation, as the off-gas temperatures required for steam generation are reached even at relatively low turbine inlet temperatures, so that NOx emissions of the gas turbine combustion chamber will be low. It is recommended that solitary gas turbines should be operated with intermediate cooling and gas turbines in combined cycle operation with intermediate heating. [German] In der vorliegenden Arbeit soll untersucht werden, in welcher Weise sich der thermische Wirkungsgrad des Gasturbinen-Prozesses durch Zwischenkuehlung, Zwischenerhitzung bzw. Zwischenkuehlung und Zwischenerhitzung verbessern laesst. Dabei sollen in erster Linie die Druckverhaeltnisse von ND-Verdichter bzw. HD-Turbine bestimmt werden, bei denen Zwischenkuehlung und Zwischenerhitzung vorgenommen werden sollen, um eine optimale Verbesserung des thermischen Wirkungsgrades zu erreichen. Die numerische Durchrechnung soll mit den Stoffwerten des realen Gases durchgefuehrt werden. Die numerischen Ergebnisse zeigen, dass die Zwischenkuehlung im Verdichter einen weit groesseren Einfluss auf den thermischen Wirkungsgrad hat als die Zwischenerhitzung in der Turbine. Letztere ist aber bei Gasturbinen fuer den Kombibetrieb von Vorteil, erreicht man doch die fuer die Dampferzeugung notwendigen Abgastemperaturen der Gasturbine schon bei relativ niedrigen Turbineneintrittstemperaturen, so dass die NO{sub x}-Emission der

  8. TRISO-Coated Fuel Processing to Support High Temperature Gas-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Del Cul, G.D.

    2002-10-01

    The initial objective of the work described herein was to identify potential methods and technologies needed to disassemble and dissolve graphite-encapsulated, ceramic-coated gas-cooled-reactor spent fuels so that the oxide fuel components can be separated by means of chemical processing. The purpose of this processing is to recover (1) unburned fuel for recycle, (2) long-lived actinides and fission products for transmutation, and (3) other fission products for disposal in acceptable waste forms. Follow-on objectives were to identify and select the most promising candidate flow sheets for experimental evaluation and demonstration and to address the needs to reduce technical risks of the selected technologies. High-temperature gas-cooled reactors (HTGRs) may be deployed in the next -20 years to (1) enable the use of highly efficient gas turbines for producing electricity and (2) provide high-temperature process heat for use in chemical processes, such as the production of hydrogen for use as clean-burning transportation fuel. Also, HTGR fuels are capable of significantly higher burn-up than light-water-reactor (LWR) fuels or fast-reactor (FR) fuels; thus, the HTGR fuels can be used efficiently for transmutation of fissile materials and long-lived actinides and fission products, thereby reducing the inventory of such hazardous and proliferation-prone materials. The ''deep-burn'' concept, described in this report, is an example of this capability. Processing of spent graphite-encapsulated, ceramic-coated fuels presents challenges different from those of processing spent LWR fuels. LWR fuels are processed commercially in Europe and Japan; however, similar infrastructure is not available for processing of the HTGR fuels. Laboratory studies on the processing of HTGR fuels were performed in the United States in the 1960s and 1970s, but no engineering-scale processes were demonstrated. Currently, new regulations concerning emissions will impact the

  9. Toward a Mechanistic Source Term in Advanced Reactors: Characterization of Radionuclide Transport and Retention in a Sodium Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Brunett, Acacia J.; Bucknor, Matthew; Grabaskas, David

    2016-04-17

    A vital component of the U.S. reactor licensing process is an integrated safety analysis in which a source term representing the release of radionuclides during normal operation and accident sequences is analyzed. Historically, source term analyses have utilized bounding, deterministic assumptions regarding radionuclide release. However, advancements in technical capabilities and the knowledge state have enabled the development of more realistic and best-estimate retention and release models such that a mechanistic source term assessment can be expected to be a required component of future licensing of advanced reactors. Recently, as part of a Regulatory Technology Development Plan effort for sodium cooled fast reactors (SFRs), Argonne National Laboratory has investigated the current state of knowledge of potential source terms in an SFR via an extensive review of previous domestic experiments, accidents, and operation. As part of this work, the significant sources and transport processes of radionuclides in an SFR have been identified and characterized. This effort examines all stages of release and source term evolution, beginning with release from the fuel pin and ending with retention in containment. Radionuclide sources considered in this effort include releases originating both in-vessel (e.g. in-core fuel, primary sodium, cover gas cleanup system, etc.) and ex-vessel (e.g. spent fuel storage, handling, and movement). Releases resulting from a primary sodium fire are also considered as a potential source. For each release group, dominant transport phenomena are identified and qualitatively discussed. The key product of this effort was the development of concise, inclusive diagrams that illustrate the release and retention mechanisms at a high level, where unique schematics have been developed for in-vessel, ex-vessel and sodium fire releases. This review effort has also found that despite the substantial range of phenomena affecting radionuclide release, the

  10. A method for calculation of forces acting on air cooled gas turbine blades based on the aerodynamic theory

    Directory of Open Access Journals (Sweden)

    Grković Vojin R.

    2013-01-01

    Full Text Available The paper presents the mathematical model and the procedure for calculation of the resultant force acting on the air cooled gas turbine blade(s based on the aerodynamic theory and computation of the circulation around the blade profile. In the conducted analysis was examined the influence of the cooling air mass flow expressed through the cooling air flow parameter λc, as well as, the values of the inlet and outlet angles β1 and β2, on the magnitude of the tangential and axial forces. The procedure and analysis were exemplified by the calculation of the tangential and axial forces magnitudes. [Projekat Ministarstva nauke Republike Srbije: Development and building the demonstrative facility for combined heat and power with gasification

  11. Study on disposal method of graphite blocks and storage of spent fuel for modular gas-cooled reactor. Joint research

    Energy Technology Data Exchange (ETDEWEB)

    Sumita, Junya; Sawa, Kazuhiro; Kunitomi, Kazuhiko [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Tsuchie, Yasuo; Urakami, Masao [Japan Atomic Power Co., Tokyo (Japan)

    2003-02-01

    This report describes the result of study on disposal method of graphite blocks in future block-type reactor. Present study was carried out within a framework of joint research, ''Research of Modular High Temperature Gas-cooled Reactors (No. 3)'', between Japan Atomic Energy Research Institute (JAERI) and the Japan Atomic Power Company (JAPCO), in 2000. In this study, activities in fuel and reflector graphite blocks were evaluated and were compared with the disposal limits defined as low-level of radioactive waste. As a result, it was found that the activity for only C-14 was higher than disposal limits for the low-level of radioactive waste and that the amount of air in the graphite is important to evaluate precisely of C-14 activity. In addition, spent fuels can be stored in air-cooled condition at least after two years cooling in the storage pool. (author)

  12. ANALYSIS OF A HIGH TEMPERATURE GAS-COOLED REACTOR POWERED HIGH TEMPERATURE ELECTROLYSIS HYDROGEN PLANT

    Energy Technology Data Exchange (ETDEWEB)

    M. G. McKellar; E. A. Harvego; A. M. Gandrik

    2010-11-01

    An updated reference design for a commercial-scale high-temperature electrolysis (HTE) plant for hydrogen production has been developed. The HTE plant is powered by a high-temperature gas-cooled reactor (HTGR) whose configuration and operating conditions are based on the latest design parameters planned for the Next Generation Nuclear Plant (NGNP). The current HTGR reference design specifies a reactor power of 600 MWt, with a primary system pressure of 7.0 MPa, and reactor inlet and outlet fluid temperatures of 322°C and 750°C, respectively. The reactor heat is used to produce heat and electric power to the HTE plant. A Rankine steam cycle with a power conversion efficiency of 44.4% was used to provide the electric power. The electrolysis unit used to produce hydrogen includes 1.1 million cells with a per-cell active area of 225 cm2. The reference hydrogen production plant operates at a system pressure of 5.0 MPa, and utilizes a steam-sweep system to remove the excess oxygen that is evolved on the anode (oxygen) side of the electrolyzer. The overall system thermal-to-hydrogen production efficiency (based on the higher heating value of the produced hydrogen) is 42.8% at a hydrogen production rate of 1.85 kg/s (66 million SCFD) and an oxygen production rate of 14.6 kg/s (33 million SCFD). An economic analysis of this plant was performed with realistic financial and cost estimating The results of the economic analysis demonstrated that the HTE hydrogen production plant driven by a high-temperature helium-cooled nuclear power plant can deliver hydrogen at a competitive cost. A cost of $3.03/kg of hydrogen was calculated assuming an internal rate of return of 10% and a debt to equity ratio of 80%/20% for a reactor cost of $2000/kWt and $2.41/kg of hydrogen for a reactor cost of $1400/kWt.

  13. High-temperature gas-cooled reactor technology development program. Annual progress report for period ending December 31, 1982

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Rittenhouse, P.L.; Bartine, D.E.; Sanders, J.P.

    1983-06-01

    During 1982 the High-Temperature Gas-Cooled Reactor (HTGR) Technology Program at Oak Ridge National Laboratory (ORNL) continued to develop experimental data required for the design and licensing of cogeneration HTGRs. The program involves fuels and materials development (including metals, graphite, ceramic, and concrete materials), HTGR chemistry studies, structural component development and testing, reactor physics and shielding studies, performance testing of the reactor core support structure, and HTGR application and evaluation studies.

  14. Thermal investigation of an internally cooled strut injector for scramjet application at moderate and hot gas conditions

    Science.gov (United States)

    Dröske, Nils C.; Förster, Felix J.; Weigand, Bernhard; von Wolfersdorf, Jens

    2017-03-01

    In this paper, we present a combined experimental and numerical approach to assess the thermal loads and the cooling mechanism of an internally cooled strut injector for a supersonic combustion ramjet. Infrared measurements of the injector surface are conducted at a moderate external flow temperature. In addition, the main flow field is investigated with the LITA technique. Main features of the cooling mechanism are identified based on experimental data. However, a full evaluation can only be obtained using a complex, conjugate CFD simulation, which couples the external and internal flow fields to the heat conduction inside the injector body. Furthermore, numerical simulations are also presented for hot gas conditions corresponding to combustion experiments. Both hydrogen, which would be used as fuel for flight tests, and air are considered as coolants. While the main features of the cooling mechanism will be shown to remain unchanged, the combustor wall temperature is found to have a significant influence on the cooling. This emphasizes the importance and the usefulness of such complex conjugate numerical simulations.

  15. The Gas-Cooled Fast Reactor: Report on Safety System Design for Decay Heat Removal

    Energy Technology Data Exchange (ETDEWEB)

    K. D. Weaver; T. Marshall; T. Y. C. Wei; E. E. Feldman; M. J. Driscoll; H. Ludewig

    2003-09-01

    The gas-cooled fast reactor (GFR) was chosen as one of the Generation IV nuclear reactor systems to be developed based on its excellent potential for sustainability through reduction of the volume and radiotoxicity of both its own fuel and other spent nuclear fuel, and for extending/utilizing uranium resources orders of magnitude beyond what the current open fuel cycle can realize. In addition, energy conversion at high thermal efficiency is possible with the current designs being considered, thus increasing the economic benefit of the GFR. However, research and development challenges include the ability to use passive decay heat removal systems during accident conditions, survivability of fuels and in-core materials under extreme temperatures and radiation, and economical and efficient fuel cycle processes. This report addresses/discusses the decay heat removal options available to the GFR, and the current solutions. While it is possible to design a GFR with complete passive safety (i.e., reliance solely on conductive and radiative heat transfer for decay heat removal), it has been shown that the low power density results in unacceptable fuel cycle costs for the GFR. However, increasing power density results in higher decay heat rates, and the attendant temperature increase in the fuel and core. Use of active movers, or blowers/fans, is possible during accident conditions, which only requires 3% of nominal flow to remove the decay heat. Unfortunately, this requires reliance on active systems. In order to incorporate passive systems, innovative designs have been studied, and a mix of passive and active systems appears to meet the requirements for decay heat removal during accident conditions.

  16. Study on the properties of the fuel compact for High Temperature Gas-cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Chung-yong; Lee, Sung-yong; Choi, Min-young; Lee, Seung-jae; Jo, Young-ho [KEPCO Nuclear Fuel, Daejeon (Korea, Republic of); Lee, Young-woo; Cho, Moon-sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    High Temperature Gas-cooled Reactors (HTGR), one of the Gen-IV reactors, have been using the fuel element which is manufactured by the graphite matrix, surrounding Tristructural-isotropic (TRISO)-coated Uranium particles. Factors with these characteristics effecting on the matrix of fuel compact are chosen and their impacts on the properties are studied. The fuel elements are considered with two types of concepts for HTGR, which are the block type reactor and the pebble bed reactor. In this paper, the cylinder-formed fuel element for the block type reactor is focused on, which consists of the large part of graphite matrix. One of the most important properties of the graphite matrix is the mechanical strength with the high reliability because the graphite matrix should be enabled to protect the TRISO particles from the irradiation environment and the impact from the outside. In this study, the three kinds of candidate graphites and the two kinds of candidate binder (Phenol and Polyvinyl butyral) were chosen and mixed with each other, formed and heated to measure mechanical properties. The objective of this research is to optimize the materials and composition of the mixture and the forming process by evaluating the mechanical properties before/after carbonization and heat treatment. From the mechanical test results, the mechanical properties of graphite pellets was related to the various conditions such as the contents and kinds of binder, the kinds of graphite and the heat treatments. In the result of the compressive strength and Vicker's hardness, the 10 wt% phenol binder added R+S graphite pellet was relatively higher mechanical properties than other pellets. The contents of Phenol binder, the kinds of graphite powder and the temperature of carbonization and heat treatment are considered important factors for the properties. To optimize the mechanical properties of fuel elements, the role of binders and the properties of graphites will be investigated as

  17. Low-Cost Manufacturing Technique for Advanced Regenerative Cooling for In-Space Cryogenic Engines Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of the proposed effort is to use selective laser melting (SLM, an additive manufacturing technique) to manufacture a hot fire-capable, water-cooled spool...

  18. Spacesuit Water Membrane Evaporator; An Enhanced Evaporative Cooling System for the Advanced Extravehicular Mobility Unit Portable Life Support System

    Science.gov (United States)

    Bue, Grant C.; Makinen, Janice V.; Miller, Sean; Campbell, Colin; Lynch, Bill; Vogel, Matt; Craft, Jesse; Wilkes, Robert; Kuehnel, Eric

    2014-01-01

    Development of the Advanced Extravehicular Mobility Unit (AEMU) portable life support subsystem (PLSS) is currently under way at NASA Johnson Space Center. The AEMU PLSS features a new evaporative cooling system, the Generation 4 Spacesuit Water Membrane Evaporator (Gen4 SWME). The SWME offers several advantages when compared with prior crewmember cooling technologies, including the ability to reject heat at increased atmospheric pressures, reduced loop infrastructure, and higher tolerance to fouling. Like its predecessors, Gen4 SWME provides nominal crew member and electronics cooling by flowing water through porous hollow fibers. Water vapor escapes through the hollow fiber pores, thereby cooling the liquid water that remains inside of the fibers. This cooled water is then recirculated to remove heat from the crew member and PLSS electronics. Test results from the backup cooling system which is based on a similar design and the subject of a companion paper, suggested that further volume reductions could be achieved through fiber density optimization. Testing was performed with four fiber bundle configurations ranging from 35,850 fibers to 41,180 fibers. The optimal configuration reduced the Gen4 SWME envelope volume by 15% from that of Gen3 while dramatically increasing the performance margin of the system. A rectangular block design was chosen over the Gen3 cylindrical design, for packaging configurations within the AEMU PLSS envelope. Several important innovations were made in the redesign of the backpressure valve which is used to control evaporation. A twin-port pivot concept was selected from among three low profile valve designs for superior robustness, control and packaging. The backpressure valve motor, the thermal control valve, delta pressure sensors and temperature sensors were incorporated into the manifold endcaps, also for packaging considerations. Flight-like materials including a titanium housing were used for all components. Performance testing

  19. Advanced gas cooled nuclear reactor materials evaluation and development program. Selection of candidate alloys. Vol. 1. Advanced gas cooled reactor systems definition

    Energy Technology Data Exchange (ETDEWEB)

    Marvin, M.D.

    1978-10-31

    Candidate alloys for a Very High Temperature Reactor (VHTR) Nuclear Process Heal (NPH) and Direct Cycle Helium Turbine (DCHT) applications in terms of the effect of the primary coolant exposure and thermal exposure were evaluated. (FS)

  20. Economic assessment of advanced flue gas desulfurization processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bierman, G. R.; May, E. H.; Mirabelli, R. E.; Pow, C. N.; Scardino, C.; Wan, E. I.

    1981-09-01

    This report presents the results of a project sponsored by the Morgantown Energy Technology Center (METC). The purpose of the study was to perform an economic and market assessment of advanced flue gas desulfurization (FGD) processes for application to coal-fired electric utility plants. The time period considered in the study is 1981 through 1990, and costs are reported in 1980 dollars. The task was divided into the following four subtasks: (1) determine the factors affecting FGD cost evaluations; (2) select FGD processes to be cost-analyzed; (3) define the future electric utility FGD system market; and (4) perform cost analyses for the selected FGD processes. The study was initiated in September 1979, and separate reports were prepared for the first two subtasks. The results of the latter two subtasks appear only in this final reprot, since the end-date of those subtasks coincided with the end-date of the overall task. The Subtask 1 report, Criteria and Methods for Performing FGD Cost Evaluations, was completed in October 1980. A slightly modified and condensed version of that report appears as appendix B to this report. The Subtask 2 report, FGD Candidate Process Selection, was completed in January 1981, and the principal outputs of that subtask appear in Appendices C and D to this report.

  1. Advanced Flue Gas Desulfurization (AFGD) Demonstration Project, A DOE Assessment

    Energy Technology Data Exchange (ETDEWEB)

    National Energy Technology Laboratory

    2001-08-31

    The AFGD process as demonstrated by Pure Air at the Bailly Station offers a reliable and cost-effective means of achieving a high degree of SO{sub 2} emissions reduction when burning high-sulfur coals. Many innovative features have been successfully incorporated in this process, and it is ready for widespread commercial use. The system uses a single-loop cocurrent scrubbing process with in-situ oxidation to produce wallboard-grade gypsum instead of wet sludge. A novel wastewater evaporation system minimizes effluents. The advanced scrubbing process uses a common absorber to serve multiple boilers, thereby saving on capital through economies of scale. Major results of the project are: (1) SO{sub 2} removal of over 94 percent was achieved over the three-year demonstration period, with a system availability exceeding 99.5 percent; (2) a large, single absorber handled the combined flue gas of boilers generating 528 MWe of power, and no spares were required; (3) direct injection of pulverized limestone into the absorber was successful; (4) Wastewater evaporation eliminated the need for liquid waste disposal; and (5) the gypsum by-product was used directly for wallboard manufacture, eliminating the need to dispose of waste sludge.

  2. Fracture behavior of advanced ceramic hot gas filters: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Singh, J.P.; Majumdar, S.; Sutaria, M.; Bielke, W. [Argonne National Lab., IL (United States). Energy Technology Div.

    1997-03-01

    This report presents the results of mechanical/microstructural evaluation, thermal shock/fatigue testing, and stress analyses of advanced hot-gas filters obtained from different manufacturers. These filters were fabricated from both monolithic ceramics and composites. The composite filters, made of both oxide and nonoxide materials, were in both as-fabricated and exposed conditions, whereas the monolithic filters were made only of nonoxide materials. Mechanical property measurement of composite filters included diametral compression testing with O-ring specimens and burst-testing of short filter segments with rubber plugs. In-situ strength of fibers in the composite filters was evaluated by microscopic technique. Thermal shock/fatigue resistance was estimated by measuring the strengths of filter specimens before and after thermal cycling from an air environment at elevated temperatures to a room temperature oil bath. Filter performance during mechanical and thermal shock/fatigue loadings was correlated with microstructural observations. Micromechanical models were developed to derive properties of composite filter constituents on the basis of measured mechanical properties of the filters. Subsequently, these properties were used to analytically predict the performance of composite filters during thermal shock loading.

  3. Advanced ceramic coating development for industrial/utility gas turbines

    Science.gov (United States)

    Vogan, J. W.; Stetson, A. R.

    1982-01-01

    A program was conducted with the objective of developing advanced thermal barrier coating (TBC) systems. Coating application was by plasma spray. Duplex, triplex and graded coatings were tested. Coating systems incorporated both NiCrAly and CoCrAly bond coats. Four ceramic overlays were tested: ZrO2.82O3; CaO.TiO2; 2CaO.SiO2; and MgO.Al2O3. The best overall results were obtained with a CaO.TiO2 coating applied to a NiCrAly bond coat. This coating was less sensitive than the ZrO2.8Y2O3 coating to process variables and part geometry. Testing with fuels contaminated with compounds containing sulfur, phosphorus and alkali metals showed the zirconia coatings were destabilized. The calcium titanate coatings were not affected by these contaminants. However, when fuels were used containing 50 ppm of vanadium and 150 ppm of magnesium, heavy deposits were formed on the test specimens and combustor components that required frequent cleaning of the test rig. During the program Mars engine first-stage turbine blades were coated and installed for an engine cyclic endurance run with the zirconia, calcium titanate, and calcium silicate coatings. Heavy spalling developed with the calcium silicate system. The zirconia and calcium titanate systems survived the full test duration. It was concluded that these two TBC's showed potential for application in gas turbines.

  4. Gas-burning air cooling developed by leading gas enterprises (Toho Gas). Nagoyaka Home Yokota, a nursing home; Ote kakusha ni miru gas reibo no saiyo jirei (Toho Gas). Tokubetsu yogo rojin home `Nagoyaka House Yokota`

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    Described herein is the air-conditioning system for Nagoyaka Home Yokota, a nursing home in Nagoya City. It is a 7-story building with a total floor area of 4,444m{sup 2}. The first and second floors are for common purposes (dinning rooms, bathrooms, etc.), and the upper floors are for a total of 39 residents. The air-conditioning system is divided into two lines, one for the residents and the other for offices, where each office is equipped with an individual heat-pump type air conditioner. The residential rooms are air-conditioned by the gas absorption type cool/hot water generating system (capacity: 120 refrigeration tons) installed on the roof, where each room is equipped with a fan coil unit on the ceiling to allow each resident to control temperature independently. The home is also equipped with gas-burning systems for hot water generators, clothes driers and cookers. These city gas burning systems support comfortableness of the home. 5 figs.

  5. Advanced Gas Reactor (AGR)-5/6/7 Fuel Irradiation Experiments in the Advanced Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    A. Joseph Palmer; David A. Petti; S. Blaine Grover

    2014-04-01

    The United States Department of Energy’s Very High Temperature Reactor (VHTR) Advanced Gas Reactor (AGR) Fuel Development and Qualification Program will be irradiating up to seven separate low enriched uranium (LEU) tri-isotopic (TRISO) particle fuel (in compact form) experiments in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). These irradiations and fuel development are being accomplished to support development of the next generation reactors in the United States. The goals of the irradiation experiments are to provide irradiation performance data to support fuel process development, to qualify fuel for normal operating conditions, to support development and validation of fuel performance and fission product transport models and codes, and to provide irradiated fuel and materials for post irradiation examination (PIE) and safety testing. The experiments, which each consist of at least five separate capsules, are being irradiated in an inert sweep gas atmosphere with individual on-line temperature monitoring and control of each capsule. The sweep gases also have on-line fission product monitoring the effluent from each capsule to track performance of the fuel during irradiation. The first two experiments (designated AGR-1 and AGR-2), have been completed. The third and fourth experiments have been combined into a single experiment designated AGR-3/4, which started its irradiation in December 2011 and is currently scheduled to be completed in April 2014. The design of the fuel qualification experiment, designated AGR-5/6/7, is well underway and incorporates lessons learned from the three previous experiments. Various design issues will be discussed with particular details related to selection of thermometry.

  6. Formation of globular clusters in atomic-cooling halos via rapid gas condensation and fragmentation during the epoch of reionization

    CERN Document Server

    Kimm, Taysun; Rosdahl, Joakim; Yi, Sukyoung

    2015-01-01

    We investigate the formation of metal-poor globular clusters (GCs) at the center of two dark matter halos with $M_{halo}\\sim4\\times10^7\\,M_\\odot$ at $z>10$ using cosmological radiation-hydrodynamics simulations. We find that very compact ($\\lesssim$ 1 pc) and massive ($\\sim6\\times10^5\\,M_\\odot$) clusters form rapidly when pristine gas collapses isothermally with the aid of efficient Ly$\\alpha$ emission during the transition from molecular-cooling halos to atomic-cooling halos. Because the local free-fall time of dense star-forming gas is very short ($\\ll 1\\,{\\rm Myr}$), a large fraction of the collapsed gas is turned into stars before stellar feedback processes blow out the gas and shut down star formation. Although the early stage of star formation is limited to a small region of the central star-forming disk, we find that the disk quickly fragments due to metal enrichment from supernovae. Sub-clusters formed in the fragmented clouds eventually merge with the main cluster at the center. We estimate using a s...

  7. Estimation of benefits from demonstrating advanced wet/dry cooling technology: a framework and partial analysis

    Energy Technology Data Exchange (ETDEWEB)

    Currie, J.W.; Foley, T.J.

    1977-09-01

    An analysis was performed to estimate reductions in future electric power generation costs expected to occur through a proposed 6- to 10-MWe demonstration of an ammonia (NH/sub 3/) cooling concept. Theoretical and empirical research on technological substitution and diffusion were reviewed in developing the analytical framework and computer model used in this analysis. Stochastic learning and market penetration functions were used to derive benefit distributions for two primary scenarios. The distributions provide not only single best estimates of the benefits, but measures of the uncertainty surrounding the estimates as well. The benefits were estimated by subtracting the net present value of expected future cooling costs if no demonstration were to take place from the net present value of expected future cooling costs if the demonstration did take place. If the public demonstration does not occur, two scenarios were hypothesized: ammonia cooling will never be commercialized; and ammonia cooling will be commercialized at a later date than if the demonstration had occurred. The analysis suggests that the benefits from a public investment in demonstration would probably exceed the estimated $10 million project cost.

  8. Development of Advanced 9Cr Ferritic-Martensitic Steels and Austenitic Stainless Steels for Sodium-Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sham, Sam [ORNL; Tan, Lizhen [ORNL; Yamamoto, Yukinori [ORNL

    2013-01-01

    Ferritic-martensitic (FM) steel Grade 92, with or without thermomechanical treatment (TMT), and austenitic stainless steels HT-UPS (high-temperature ultrafine precipitate strengthening) and NF709 were selected as potential candidate structural materials in the U.S. Sodium-cooled Fast Reactor (SFR) program. The objective is to develop advanced steels with improved properties as compared with reference materials such as Grade 91 and Type 316H steels that are currently in nuclear design codes. Composition modification and/or processing optimization (e.g., TMT and cold-work) were performed to improve properties such as resistance to thermal aging, creep, creep-fatigue, fracture, and sodium corrosion. Testings to characterize these properties for the advanced steels were conducted by the Idaho National Laboratory, the Argonne National Laboratory and the Oak Ridge National Laboratory under the U.S. SFR program. This paper focuses on the resistance to thermal aging and creep of the advanced steels. The advanced steels exhibited up to two orders of magnitude increase in creep life compared to the reference materials. Preliminary results on the weldment performance of the advanced steels are also presented. The superior performance of the advanced steels would improve reactor design flexibility, safety margins and economics.

  9. Cooling of Gas Turbines I - Effects of Addition of Fins to Blade Tips and Rotor, Admission of Cooling Air Through Part of Nozzles, and Change in Thermal Conductivity of Turbine Components

    Science.gov (United States)

    Brown, Byron

    1947-01-01

    An analysis was developed for calculating the radial temperature distribution in a gas turbine with only the temperatures of the gas and the cooling air and the surface heat-transfer coefficient known. This analysis was applied to determine the temperatures of a complete wheel of a conventional single-stage impulse exhaust-gas turbine. The temperatures were first calculated for the case of the turbine operating at design conditions of speed, gas flow, etc. and with only the customary cooling arising from exposure of the outer blade flange and one face of the rotor to the air. Calculations were next made for the case of fins applied to the outer blade flange and the rotor. Finally the effects of using part of the nozzles (from 0 to 40 percent) for supplying cooling air and the effects of varying the metal thermal conductivity from 12 to 260 Btu per hour per foot per degree Farenheit on the wheel temperatures were determined. The gas temperatures at the nozzle box used in the calculations ranged from 1600F to 2000F. The results showed that if more than a few hundred degrees of cooling of turbine blades are required other means than indirect cooling with fins on the rotor and outer blade flange would be necessary. The amount of cooling indicated for the type of finning used could produce some improvement in efficiency and a large increase in durability of the wheel. The results also showed that if a large difference is to exist between the effective temperature of the exhaust gas and that of the blade material, as must be the case with present turbine materials and the high exhaust-gas temperatures desired (2000F and above), two alternatives are suggested: (a) If metal with a thermal conductivity comparable with copper is used, then the blade temperature can be reduced by strong cooling at both the blade tip and root. The center of the blade will be less than 2000F hotter than the ends; (b) With low conductivity materials some method of direct cooling other than

  10. Advanced modeling of oxy-fuel combustion of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Chungen Yin

    2011-01-15

    The main goal of this small-scale project is to investigate oxy-combustion of natural gas (NG) through advanced modeling, in which radiation, chemistry and mixing will be reasonably resolved. 1) A state-of-the-art review was given regarding the latest R and D achievements and status of oxy-fuel technology. The modeling and simulation status and achievements in the field of oxy-fuel combustion were also summarized; 2) A computer code in standard c++, using the exponential wide band model (EWBM) to evaluate the emissivity and absorptivity of any gas mixture at any condition, was developed and validated in detail against data in literature. A new, complete, and accurate WSGGM, applicable to both air-fuel and oxy-fuel combustion modeling and applicable to both gray and non-gray calculation, was successfully derived, by using the validated EWBM code as the reference mode. The new WSGGM was implemented in CFD modeling of two different oxy-fuel furnaces, through which its great, unique advantages over the currently most widely used WSGGM were demonstrated. 3) Chemical equilibrium calculations were performed for oxy-NG flame and air-NG flame, in which dissociation effects were considered to different degrees. Remarkable differences in oxy-fuel and air-fuel combustion were revealed, and main intermediate species that play key roles in oxy-fuel flames were identified. Different combustion mechanisms are compared, e.g., the most widely used 2-step global mechanism, refined 4-step global mechanism, a global mechanism developed for oxy-fuel using detailed chemical kinetic modeling (CHEMKIN) as reference. 4) Over 15 CFD simulations were done for oxy-NG combustion, in which radiation, chemistry, mixing, turbulence-chemistry interactions, and so on were thoroughly investigated. Among all the simulations, RANS combined with 2-step and refined 4-step mechanism, RANS combined with CHEMKIN-based new global mechanism for oxy-fuel modeling, and LES combined with different combustion

  11. Heat and mass transfer problems for film cooling

    Energy Technology Data Exchange (ETDEWEB)

    Leontiev, A.I.

    1999-07-01

    An advance in many branches of engineering is connected with using of more and more high working temperatures, perfection of cooling systems of power installations and further development of the theory of heat transfer. One of the most promising methods of thermal protection of heating surfaces is using of the gas film cooling. Despite intensive development of numerical methods of calculation of film cooling problems, simple and reliable correlations, which are based on clear physical models, that make it possible to generalize experimental data for complex boundary conditions, are necessary for complex engineering calculations. It is well known, that an increase in an initial gas temperature of the gas at the turbine inlet is the basic method to advance technical and economical parameters of the gas turbine units and engines. Modern gas turbine engines are designed to operate at inlet temperatures of 1,800--2,000 K, which are far above the allowable temperatures of the metal. Under these conditions, the turbine blades should be cooled in order to ensure a reasonable lifetime. In the paper the review of calculation methods and of experimental results on heat transfer under film cooling is presented. The effect of an arrangement of film cooling, longitudinal gradient of pressure, nonisothermality and compressibility of gas, swirling of flow, and turbulent pulsations of the main gas flow on effectiveness of the gas film cooling is considered. A method of calculation of combined cooling (film, porous or transpiration and convective) is proposed.

  12. Defining the needs for gas centrifuge enrichment plants advanced safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Boyer, Brian David [Los Alamos National Laboratory; Erpenbeck, Heather H [Los Alamos National Laboratory; Miller, Karen A [Los Alamos National Laboratory; Swinhoe, Martyn T [Los Alamos National Laboratory; Ianakiev, Kiril [Los Alamos National Laboratory; Marlow, Johnna B [Los Alamos National Laboratory

    2010-04-05

    Current safeguards approaches used by the International Atomic Energy Agency (IAEA) at gas centrifuge enrichment plants (GCEPs) need enhancement in order to verify declared low-enriched (LEU) production, detect undeclared LEU production and detect highly enriched uranium (HEU) production with adequate detection probability using nondestructive assay (NDA) techniques. At present inspectors use attended systems, systems needing the presence of an inspector for operation, during inspections to verify the mass and {sup 235}U enrichment of declared UF{sub 6} containers used in the process of enrichment at GCEPs. In verifying declared LEU production, the inspectors also take samples for off-site destructive assay (DA) which provide accurate data, with 0.1% to 0.5% measurement uncertainty, on the enrichment of the UF{sub 6} feed, tails, and product. However, taking samples of UF{sub 6} for off-site analysis is a much more labor and resource intensive exercise for the operator and inspector. Furthermore, the operator must ship the samples off-site to the IAEA laboratory which delays the timeliness of results and interruptions to the continuity of knowledge (CofK) of the samples during their storage and transit. This paper contains an analysis of possible improvements in unattended and attended NDA systems such as process monitoring and possible on-site analysis of DA samples that could reduce the uncertainty of the inspector's measurements and provide more effective and efficient IAEA GCEPs safeguards. We also introduce examples advanced safeguards systems that could be assembled for unattended operation.

  13. Advanced fuels modeling: Evaluating the steady-state performance of carbide fuel in helium-cooled reactors using FRAPCON 3.4

    Science.gov (United States)

    Hallman, Luther, Jr.

    Uranium carbide (UC) has long been considered a potential alternative to uranium dioxide (UO2) fuel, especially in the context of Gen IV gas-cooled reactors. It has shown promise because of its high uranium density, good irradiation stability, and especially high thermal conductivity. Despite its many benefits, UC is known to swell at a rate twice that of UO2. However, the swelling phenomenon is not well understood, and we are limited to a weak empirical understanding of the swelling mechanism. One suggested cladding for UC is silicon carbide (SiC), a ceramic that demonstrates a number of desirable properties. Among them are an increased corrosion resistance, high mechanical strength, and irradiation stability. However, with increased temperatures, SiC exhibits an extremely brittle nature. The brittle behavior of SiC is not fully understood and thus it is unknown how SiC would respond to the added stress of a swelling UC fuel. To better understand the interaction between these advanced materials, each has been implemented into FRAPCON, the preferred fuel performance code of the Nuclear Regulatory Commission (NRC); additionally, the material properties for a helium coolant have been incorporated. The implementation of UC within FRAPCON required the development of material models that described not only the thermophysical properties of UC, such as thermal conductivity and thermal expansion, but also models for the swelling, densification, and fission gas release associated with the fuel's irradiation behavior. This research is intended to supplement ongoing analysis of the performance and behavior of uranium carbide and silicon carbide in a helium-cooled reactor.

  14. Taguchi Based Regression Analysis of End-Wall Film Cooling in a Gas Turbine Cascade with Single Row of Holes

    Science.gov (United States)

    Ravi, D.; Parammasivam, K. M.

    2016-09-01

    Numerical investigations were conducted on a turbine cascade, with end-wall cooling by a single row of cylindrical holes, inclined at 30°. The mainstream fluid was hot air and the coolant was CO2 gas. Based on the Reynolds number, the flow was turbulent at the inlet. The film hole row position, its pitch and blowing ratio was varied with five different values. Taguchi approach was used in designing a L25 orthogonal array (OA) for these parameters. The end-wall averaged film cooling effectiveness (bar η) was chosen as the quality characteristic. CFD analyses were carried out using Ansys Fluent on computational domains designed with inputs from OA. Experiments were conducted for one chosen OA configuration and the computational results were found to correlate well with experimental measurements. The responses from the CFD analyses were fed to the statistical tool to develop a correlation for bar η using regression analysis.

  15. Enhancing the efectiveness of film cooling

    Institute of Scientific and Technical Information of China (English)

    Tom I-P.Shih; Sangkwon Na

    2007-01-01

    Advanced gas turbine stages are designed to operate at increasingly higher inlet temperatures to increase thermal efficiency and specific power output.To maintain durability and reasonable life,film cooling is needed in addition to internal cooling,especially for the first stage.Film cooling lowers material temperature by forced convection inside film-cooling holes and by forming a layer of coolant about component surfaces to insulate them from the hot gases.Unfortunately,each cooling jet forms a pair of counter-rotating vortices that entrains hot gas and causes the film-cooling jet to lift off from the surface that it is intended to protect.This paper gives an overview of efforts to enhance the effectiveness of film-cooling.This paper also describes two new design concepts.One design concept seeks to minimize the entrainment of hot gases underneath of film-cooling jets by using flow-aligned blockers.The other design concept shifts the interaction between the approaching hot gas and the cooling jet to occur further above the surface by using an upstream ramp.For both design concepts,computational fluid dynamics results are presented to examine their usefulness in enhancing film-cooling effectiveness.

  16. Experimental investigation of gas turbine airfoil aerodynamic performance without and with film cooling in an annular sector cascade

    Energy Technology Data Exchange (ETDEWEB)

    Wiers, S.H.

    2002-02-01

    The steady growing of industrialization, the densification of the anthroposphere, the increasing concern over the effects of gas turbine cruise emissions on the atmosphere threaten the growth of air transportation, and the perception about the possible climatic impact of CO{sub 2} emissions causes a public distinctive sense of responsibility. The conventional energy production techniques, which are based on fossil fuel, will keep its central importance within the global energy production. Forecasts about the increasing air transportation give duplication in the next 10-15 years. The optimization of the specific fuel consumption is necessary to decrease the running costs and the pollution emissions in the atmosphere, which makes an increased process efficiency of stationary turbines as well as of jet engines essential. This leads to the necessity of an increased thermodynamic efficiency of the overall process and the optimization of the aerodynamic components. Due to the necessity of more detailed three-dimensional data on the behavior of film cooled blades an annular sector cascade turbine test facility has gone into service. The annular sector cascade facility is a relative cost efficient solution compared to a full annular facility to investigate three-dimensional effects on a non cooled and cooled turbine blade. The aerodynamic investigations on the annular sector cascade facility are part of a broad perspective where experimental data from a hot annular sector cascade facility and the cold annular sector facility are used to verify, calibrate and understand the physics for both internal and external calculation methods for flow and heat transfer prediction. The objective of the present study is the design and validation of a cold flow annular sector cascade facility, which meets the flow conditions in a modem turbine as close as possible, with emphasis on achieving periodic flow conditions. The first part of this study gives the necessary background on this

  17. Advanced Refrigerant-Based Cooling Technologies for Information and Communication Infrastructure (ARCTIC)

    Energy Technology Data Exchange (ETDEWEB)

    Salamon, Todd

    2012-12-13

    Faster, more powerful and dense computing hardware generates significant heat and imposes considerable data center cooling requirements. Traditional computer room air conditioning (CRAC) cooling methods are proving increasingly cost-ineffective and inefficient. Studies show that using the volume of room air as a heat exchange medium is wasteful and allows for substantial mixing of hot and cold air. Further, it limits cabinet/frame/rack density because it cannot effectively cool high heat density equipment that is spaced closely together. A more cost-effective, efficient solution for maximizing heat transfer and enabling higher heat density equipment frames can be accomplished by utilizing properly positioned phase change or two-phase pumped refrigerant cooling methods. Pumping low pressure, oil-free phase changing refrigerant through microchannel heat exchangers can provide up to 90% less energy consumption for the primary cooling loop within the room. The primary benefits of such a solution include reduced energy requirements, optimized utilization of data center space, and lower OPEX and CAPEX. Alcatel-Lucent recently developed a modular cooling technology based on a pumped two-phase refrigerant that removes heat directly at the shelf level of equipment racks. The key elements that comprise the modular cooling technology consist of the following. A pump delivers liquid refrigerant to finned microchannel heat exchangers mounted on the back of equipment racks. Fans drive air through the equipment shelf, where the air gains heat dissipated by the electronic components therein. Prior to exiting the rack, the heated air passes through the heat exchangers, where it is cooled back down to the temperature level of the air entering the frame by vaporization of the refrigerant, which is subsequently returned to a condenser where it is liquefied and recirculated by the pump. All the cooling air enters and leaves the shelves/racks at nominally the same temperature. Results

  18. Study on a method for loading a Li compound to produce tritium using high-temperature gas-cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Nakaya, Hiroyuki, E-mail: nakaya@nucl.kyushu-u.ac.jp [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 8190395 (Japan); Matsuura, Hideaki [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, 744 Motooka, Fukuoka 8190395 (Japan); Katayama, Kazunari [Department of Advanced Energy Engineering Science, Kyushu University, 6-1 Kasuga-koen, Kasuga 8168580 (Japan); Goto, Minoru; Nakagawa, Shigeaki [Japan Atomic Energy Agency, 4002 Oarai, Ibaraki (Japan)

    2015-10-15

    Highlights: • Tritium production by a high-temperature gas-cooled reactor was studied. • The loading method considering tritium outflow suppression was estimated. • A reactor with 600 MWt produced 400–600 g of tritium for 180 days. • A possibility that tritium outflow can be sufficiently suppressed was shown. - Abstract: Tritium production using high-temperature gas-cooled reactors and its outflow from the region loading Li compound into the helium coolant are estimated when considering the suppression of tritium outflow. A Li rod containing a cylindrical Li compound placed in an Al{sub 2}O{sub 3} cladding tube is assumed as a method for loading Li compound. A gas turbine high-temperature reactor of 300 MW electrical nominal capacity (GTHTR300) with 600 MW thermal output power is considered and modeled using the continuous-energy Monte Carlo transport code MVP-BURN, where burn-up simulations are carried out. Tritium outflow is estimated from equilibrium solution for the tritium diffusion equation in the cladding tube. A GTHTR300 can produce 400–600 g of tritium over a 180-day operation using the chosen method of loading the Li compound while minimizing tritium outflow from the cladding tube. Optimizing tritium production while suppressing tritium outflow is discussed.

  19. Insights into gas heating and cooling in the disc of NGC 891 from Herschel far-infrared spectroscopy

    CERN Document Server

    Hughes, T M; Schirm, M R P; Parkin, T J; De Looze, I; Wilson, C D; Bendo, G J; Baes, M; Fritz, J; Boselli, A; Cooray, A; Cormier, D; Karczewski, O Ł; Lebouteiller, V; Lu, N; Madden, S C; Spinoglio, L; Viaene, S

    2014-01-01

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in the nearby edge-on spiral galaxy, NGC 891: [CII] 158 $\\mu$m, [NII] 122, 205 $\\mu$m, [OI] 63, 145 $\\mu$m, and [OIII] 88 $\\mu$m. We find that the photoelectric heating efficiency of the gas, traced via the ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ ratio, varies from a mean of 3.5$\\times$10$^{-3}$ in the centre up to 8$\\times$10$^{-3}$ at increasing radial and vertical distances in the disc. A decrease in ([CII]+[OII]63)/$F_{\\mathrm{TIR}}$ but constant ([CII]+[OI]63)/$F_{\\mathrm{PAH}}$ with increasing FIR colour suggests that polycyclic aromatic hydrocarbons (PAHs) may become important for gas heating in the central regions. We compare the observed flux of the FIR cooling lines and total IR emission with the predicted flux from a PDR model to determine the gas density, surface temperature and the strength of the incident far-ultraviolet (FUV) radiation field, $G_{0}$. Resolving details on physical scales of ~0.6 kpc, a p...

  20. Microgravity experiments on boiling and applications: research activity of advanced high heat flux cooling technology for electronic devices in Japan.

    Science.gov (United States)

    Suzuki, Koichi; Kawamura, Hiroshi

    2004-11-01

    Research and development on advanced high heat flux cooling technology for electronic devices has been carried out as the Project of Fundamental Technology Development for Energy Conservation, promoted by the New Energy and Industrial Technology Development Organization of Japan (NEDO). Based on the microgravity experiments on boiling heat transfer, the following useful results have obtained for the cooling of electronic devices. In subcooled flow boiling in a small channel, heat flux increases considerably more than the ordinary critical heat flux with microbubble emission in transition boiling, and dry out of the heating surface is disturbed. Successful enhancement of heat transfer is achieved by a capillary effect from grooved surface dual subchannels on the liquid supply. The critical heat flux increases 30-40 percent more than for ordinary subchannels. A self-wetting mechanism has been proposed, following investigation of bubble behavior in pool boiling of binary mixtures under microgravity. Ideas and a new concept have been proposed for the design of future cooling system in power electronics.

  1. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1999-04-01

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

  2. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    None

    1998-12-31

    The objective of this project is to develop a hot-gas desulfurization process scheme for control of H{sub 2}S in HTHP coal gas that can be more simply and economically integrated with known regenerable sorbents in DOE/METC-sponsored work than current leading hot-gas desulfurization technologies. In addition to being more economical, the process scheme to be developed must yield an elemental sulfur byproduct.

  3. Advances in the Partial Oxidation of Methane to Synthesis Gas

    Institute of Scientific and Technical Information of China (English)

    Quanli Zhu; Xutao Zhao; Youquan Deng

    2004-01-01

    The conversion and utilization of natural gas is of significant meaning to the national economy,even to the everyday life of people. However, it has not become a popular industrial process as expected due to the technical obstacles. In the past decades, much investigation into the conversion of methane,predominant component of natural gas, has been carried out. Among the possible routes of methane conversion, the partial oxidation of methane to synthesis gas is considered as an effective and economically feasible one. In this article, a brief review of recent studies on the mechanism of the partial oxidation of methane to synthesis gas together with catalyst development is wherein presented.

  4. Formation of van der Waals molecules in buffer gas cooled magnetic traps

    CERN Document Server

    Brahms, N; Zhang, P; los, J K; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-01-01

    We show that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10^12 cm^-3. We explore the spin relaxation of these molecules in buffer gas loaded magnetic traps, and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T^6 thermal dependence of spin change in buffer gas trapped silver (Ag) is accounted for by the formation and spin change of AgHe, thus providing evidence for molecular formation in a buffer gas trap.

  5. Signatures of cool gas fueling a star-forming galaxy at redshift 2.3.

    Science.gov (United States)

    Bouché, N; Murphy, M T; Kacprzak, G G; Péroux, C; Contini, T; Martin, C L; Dessauges-Zavadsky, M

    2013-07-05

    Galaxies are thought to be fed by the continuous accretion of intergalactic gas, but direct observational evidence has been elusive. The accreted gas is expected to orbit about the galaxy's halo, delivering not just fuel for star formation but also angular momentum to the galaxy, leading to distinct kinematic signatures. We report observations showing these distinct signatures near a typical distant star-forming galaxy, where the gas is detected using a background quasar passing 26 kiloparsecs from the host. Our observations indicate that gas accretion plays a major role in galaxy growth because the estimated accretion rate is comparable to the star-formation rate.

  6. Mathematical Model of Two Phase Flow in Natural Draft Wet-Cooling Tower Including Flue Gas Injection

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2016-01-01

    Full Text Available The previously developed model of natural draft wet-cooling tower flow, heat and mass transfer is extended to be able to take into account the flow of supersaturated moist air. The two phase flow model is based on void fraction of gas phase which is included in the governing equations. Homogeneous equilibrium model, where the two phases are well mixed and have the same velocity, is used. The effect of flue gas injection is included into the developed mathematical model by using source terms in governing equations and by using momentum flux coefficient and kinetic energy flux coefficient. Heat and mass transfer in the fill zone is described by the system of ordinary differential equations, where the mass transfer is represented by measured fill Merkel number and heat transfer is calculated using prescribed Lewis factor.

  7. Spectral narrowing of coherent population trapping resonance in laser-cooled and room-temperature atomic gas

    Indian Academy of Sciences (India)

    S Pradhan; S Mishra; R Behera; N Kawade; A K Das

    2014-02-01

    We have investigated coherent population trapping (CPT) in laser-cooled as well as room-temperature (with and without buffer gas) rubidium atoms. The characteristic broad signal profile emerging from the two-photon Raman resonance for room-temperature atomic vapour is consistent with the theoretical calculation incorporating associated thermal averaging. The spectral width of the dark resonance obtained with cold atoms is found to be broadened, compared to roomtemperature vapour cell, due to the feeble role played by thermal averaging, although the cold atomic sample significantly overcomes the limitation of the transit time broadening. An alternative way to improve transit time is to use a buffer gas, with which we demonstrate that the coherent population trapping signal width is reduced to < 540 Hz.

  8. Numerical Simulation of Three-dimensional Heat and Mass Transfer in Spray Cooling of Converter Gas in a Venturi Scrubber

    Institute of Scientific and Technical Information of China (English)

    LU Tao; WANG Kuisheng

    2009-01-01

    In order to predict the pressure drop, collection efficiency, velocity, temperature and mole fraction of vapor in an industrial venturi scrubber with water spraying for converter gas cooling, a three-dimensional model of heat and mass transfer with phase change is established. The gas flow and liquid droplets are treated as a continuous phase with a Eulerian approach and as a discrete phase with a Lagrangian approach, respectively. The coupled problem of heat, force, and mass transfers between gas flow and liquid droplets is solved by a commercial computational fluid dynamics(CFD) package, FLUENT. The numerical results show that the water injections have an important influence on the distributions of pressure, velocity, temperature, and mole fraction of vapor, especially for the spraying region in the throat. In the spraying region, the pressure drop is higher and the velocity is lower than in other regions due to the gas-droplet drag, while the temperature is lower because the droplet absorbs large amounts of heat from the high temperature gas and the mole fraction of vapor is higher due to the phase change of the liquid droplet. A number of cases with different water-to-gas volume flow ratios and baffle openings were simulated. The dependence of pressure drop, velocity, temperature, mole fraction of vapor, and collection efficiency on both the water-to-gas volume flow ratio and baffle opening are analyzed. The good agreements between simulation results and experiment data of pressure drop, temperature, and collection efficiency validate the model. The model should facilitate optimization of the venturi scrubber design in order to give better performance with lower pressure drops and higher collection efficiency.

  9. Critical Current and Stability of MgB$_2$ Twisted-Pair DC Cable Assembly Cooled by Helium Gas

    CERN Document Server

    AUTHOR|(CDS)2069632; Ballarino, Amalia; Yang, Yifeng; Young, Edward Andrew; Bailey, Wendell; Beduz, Carlo

    2013-01-01

    Long length superconducting cables/bus-bars cooled by cryogenic gases such as helium operating over a wider temperature range are a challenging but exciting technical development prospects, with applications ranging from super-grid transmission to future accelerator systems. With limited existing knowledge and previous experiences, the cryogenic stability and quench protection of such cables are crucial research areas because the heat transfer is reduced and temperature gradient increased compared to liquid cryogen cooled cables. V-I measurements on gas-cooled cables over a significant length are an essential step towards a fully cryogenic stabilized cable with adequate quench protection. Prototype twisted-pair cables using high-temperature superconductor and MgB2 tapes have been under development at CERN within the FP7 EuCARD project. Experimental studies have been carried out on a 5-m-long multiple MgB$_2$ cable assembly at different temperatures between 20 and 30 K. The subcables of the assembly showed sim...

  10. Laser cooling of dense atomic gases by collisional redistribution of radiation and spectroscopy of molecular dimers in a dense buffer gas environment

    CERN Document Server

    Saß, Anne; Christopoulos, Stavros; Knicker, Katharina; Moroshkin, Peter; Weitz, Martin

    2014-01-01

    We study laser cooling of atomic gases by collisional redistribution of fluorescence. In a high pressure buffer gas regime, frequent collisions perturb the energy levels of alkali atoms, which allows for the absorption of a far red detuned irradiated laser beam. Subsequent spontaneous decay occurs close to the unperturbed resonance frequency, leading to a cooling of the dense gas mixture by redistribution of fluorescence. Thermal deflection spectroscopy indicates large relative temperature changes down to and even below room temperature starting from an initial cell temperature near 700 K. We are currently performing a detailed analysis of the temperature distribution in the cell. As we expect this cooling technique to work also for molecular-noble gas mixtures, we also present initial spectroscopic experiments on alkali-dimers in a dense buffer gas surrounding.

  11. Experimental validation of advanced regulations for superconducting magnet cooling undergoing periodic heat loads

    Science.gov (United States)

    Lagier, B.; Rousset, B.; Hoa, C.; Bonnay, P.

    2014-01-01

    Superconducting magnets used in tokamaks undergo periodic heat load caused by cycling plasma operations inducing AC losses, neutrons fluxes and eddy currents in magnet structures. In the cryogenic system of JT60-SA tokamak, the Auxiliary Cold Box (ACB) distributes helium from the refrigerator to the cryogenic users and in particular to the superconducting magnets. ACB comprises a saturated helium bath with immersed heat exchangers, extracting heat from independent cooling loops. The supercritical helium flow in each cooling loop is driven by a cold circulator. In order to safely operate the refrigerator during plasma pulses, the interface between the ACB and the refrigerator shall be as stable as possible, with well-balanced bath inlet and outlet mass flows during cycling operation. The solution presented in this paper relies on a combination of regulations to smooth pulsed heat loads and to keep a constant refrigeration power during all the cycle. Two smoothing strategies are presented, both regulating the outlet mass flow of the bath: the first one using the bath as a thermal buffer and the second one storing energy in the loop by varying the cold circulator speed. The bath outlet mass flow is also controlled by an immersed resistive heater which enables a constant evaporation rate in the bath when power coming from the loops is decreasing. The refrigeration power is controlled so that the compensating power remains within an acceptable margin. Experimental validation is achieved using the HELIOS facility. This facility running at CEA Grenoble since 2010 is a scaled down model of the ACB bath and Central Solenoid magnet cooling loop of the JT60-SA tokamak. Test results show performances and robustness of the regulations.

  12. Experimental validation of advanced regulations for superconducting magnet cooling undergoing periodic heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Lagier, B.; Rousset, B.; Hoa, C.; Bonnay, P. [CEA Grenoble INAC/SBT, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2014-01-29

    Superconducting magnets used in tokamaks undergo periodic heat load caused by cycling plasma operations inducing AC losses, neutrons fluxes and eddy currents in magnet structures. In the cryogenic system of JT60-SA tokamak, the Auxiliary Cold Box (ACB) distributes helium from the refrigerator to the cryogenic users and in particular to the superconducting magnets. ACB comprises a saturated helium bath with immersed heat exchangers, extracting heat from independent cooling loops. The supercritical helium flow in each cooling loop is driven by a cold circulator. In order to safely operate the refrigerator during plasma pulses, the interface between the ACB and the refrigerator shall be as stable as possible, with well-balanced bath inlet and outlet mass flows during cycling operation. The solution presented in this paper relies on a combination of regulations to smooth pulsed heat loads and to keep a constant refrigeration power during all the cycle. Two smoothing strategies are presented, both regulating the outlet mass flow of the bath: the first one using the bath as a thermal buffer and the second one storing energy in the loop by varying the cold circulator speed. The bath outlet mass flow is also controlled by an immersed resistive heater which enables a constant evaporation rate in the bath when power coming from the loops is decreasing. The refrigeration power is controlled so that the compensating power remains within an acceptable margin. Experimental validation is achieved using the HELIOS facility. This facility running at CEA Grenoble since 2010 is a scaled down model of the ACB bath and Central Solenoid magnet cooling loop of the JT60-SA tokamak. Test results show performances and robustness of the regulations.

  13. Ambient Laboratory Coater for Advanced Gas Reactor Fuel Development

    Energy Technology Data Exchange (ETDEWEB)

    Duane D. Bruns; Robert M. Counce; Irma D. Lima Rojas

    2010-06-09

    this research is targeted at developing improved experimentally-based scaling relationships for the hydrodynamics of shallow, gas-spouted beds of dense particles. The work is motivated by the need to more effctively scale up shallow spouted beds used in processes such as in the coating of nuclear fuel particles where precise control of solids and gas circulation is critically important. Experimental results reported here are for a 50 mm diameter spouted bed containing two different types of bed solids (alumina and zirconia) at different static bed depths and fluidized by air and helium. Measurements of multiple local average pressures, inlet gas pressure fluctuations, and spout height were used to characterize the bed hydrodynamics for each operating condition. Follow-on studies are planned that include additional variations in bed size, particle properties, and fluidizing gas. The ultimate objective is to identify the most important non-dimensional hydrodynamic scaling groups and possible spouted-bed design correlations based on these groups.

  14. Preliminary Design Study of Medium Sized Gas Cooled Fast Reactor with Natural Uranium as Fuel Cycle Input

    Science.gov (United States)

    Meriyanti, Su'ud, Zaki; Rijal, K.; Zuhair, Ferhat, A.; Sekimoto, H.

    2010-06-01

    In this study a fesibility design study of medium sized (1000 MWt) gas cooled fast reactors which can utilize natural uranium as fuel cycle input has been conducted. Gas Cooled Fast Reactor (GFR) is among six types of Generation IV Nuclear Power Plants. GFR with its hard neuron spectrum is superior for closed fuel cycle, and its ability to be operated in high temperature (850° C) makes various options of utilizations become possible. To obtain the capability of consuming natural uranium as fuel cycle input, modified CANDLE burn-up scheme[1-6] is adopted this GFR system by dividing the core into 10 parts of equal volume axially. Due to the limitation of thermal hydraulic aspects, the average power density of the proposed design is selected about 70 W/cc. As an optimization results, a design of 1000 MWt reactors which can be operated 10 years without refueling and fuel shuffling and just need natural uranium as fuel cycle input is discussed. The average discharge burn-up is about 280 GWd/ton HM. Enough margin for criticallity was obtained for this reactor.

  15. Enormous disc of cool gas surrounding the nearby powerful radio galaxy NGC 612 (PKS 0131-36)

    CERN Document Server

    Emonts, B H C; Oosterloo, T A; Holt, J; Tadhunter, C N; Van der Hulst, J M; Ojha, R; Sadler, E M

    2008-01-01

    We present the detection of an enormous disc of cool neutral hydrogen (HI) gas surrounding the S0 galaxy NGC 612, which hosts one of the nearest powerful radio sources (PKS 0131-36). Using the Australia Telescope Compact Array, we detect M_HI = 1.8 x 10^9 M_sun of HI emission-line gas that is distributed in a 140 kpc wide disc-like structure along the optical disc and dust-lane of NGC 612. The bulk of the gas in the disc appears to be settled in regular rotation with a total velocity range of 850 km/s, although asymmetries in this disc indicate that perturbations are being exerted on part of the gas, possibly by a number of nearby companions. The HI disc in NGC 612 suggests that the total mass enclosed by the system is M_enc ~ 2.9 x 10^12 sin^-2(i) M_sun, implying that this early-type galaxy contains a massive dark matter halo. We also discuss an earlier study by Holt et al. that revealed the presence of a prominent young stellar population at various locations throughout the disc of NGC 612, indicating that ...

  16. Advanced phase change materials and systems for solar passive heating and cooling of residential buildings

    Energy Technology Data Exchange (ETDEWEB)

    Salyer, I.O.; Sircar, A.K.; Dantiki, S.

    1988-01-01

    During the last three years under the sponsorship of the DOE Solar Passive Division, the University of Dayton Research Institute (UDRI) has investigated four phase change material (PCM) systems for utility in thermal energy storage for solar passive heating and cooling applications. From this research on the basis of cost, performance, containment, and environmental acceptability, we have selected as our current and most promising series of candidate phase change materials, C-15 to C-24 linear crystalline alkyl hydrocarbons. The major part of the research during this contract period was directed toward the following three objectives. Find, test, and develop low-cost effective phase change materials (PCM) that melt and freeze sharply in the comfort temperature range of 73--77{degree}F for use in solar passive heating and cooling of buildings. Define practical materials and processes for fire retarding plasterboard/PCM building products. Develop cost-effective methods for incorporating PCM into building construction materials (concrete, plasterboard, etc.) which will lead to the commercial manufacture and sale of PCM-containing products resulting in significant energy conservation.

  17. Advanced industrial gas turbine technology readiness demonstration program. Phase II. Final report: compressor rig fabrication assembly and test

    Energy Technology Data Exchange (ETDEWEB)

    Schweitzer, J. K.; Smith, J. D.

    1981-03-01

    The results of a component technology demonstration program to fabricate, assemble and test an advanced axial/centrifugal compressor are presented. This work was conducted to demonstrate the utilization of advanced aircraft gas turbine cooling and high pressure compressor technology to improve the performance and reliability of future industrial gas turbines. Specific objectives of the compressor component testing were to demonstrate 18:1 pressure ratio on a single spool at 90% polytropic efficiency with 80% fewer airfoils as compared to current industrial gas turbine compressors. The compressor design configuration utilizes low aspect ratio/highly-loaded axial compressor blading combined with a centrifugal backend stage to achieve the 18:1 design pressure ratio in only 7 stages and 281 axial compressor airfoils. Initial testing of the compressor test rig was conducted with a vaneless centrifugal stage diffuser to allow documentation of the axial compressor performance. Peak design speed axial compressor performance demonstrated was 91.8% polytropic efficiency at 6.5:1 pressure ratio. Subsequent documentation of the combined axial/centrifugal performance with a centrifugal stage pipe diffuser resulted in the demonstration of 91.5% polytropic efficiency and 14% stall margin at the 18:1 overall compressor design pressure ratio. The demonstrated performance not only exceeded the contract performance goals, but also represents the highest known demonstrated compressor performance in this pressure ratio and flow class. The performance demonstrated is particularly significant in that it was accomplished at airfoil loading levels approximately 15% higher than that of current production engine compressor designs. The test results provide conclusive verification of the advanced low aspect ratio axial compressor and centrifugal stage technologies utilized.

  18. CMC Technology Advancements for Gas Turbine Engine Applications

    Science.gov (United States)

    Grady, Joseph E.

    2013-01-01

    CMC research at NASA Glenn is focused on aircraft propulsion applications. The objective is to enable reduced engine emissions and fuel consumption for more environmentally friendly aircraft. Engine system studies show that incorporation of ceramic composites into turbine engines will enable significant reductions in emissions and fuel burn due to increased engine efficiency resulting from reduced cooling requirements for hot section components. This presentation will describe recent progress and challenges in developing fiber and matrix constituents for 2700 F CMC turbine applications. In addition, ongoing research in the development of durable environmental barrier coatings, ceramic joining integration technologies and life prediction methods for CMC engine components will be reviewed.

  19. Regional cooling caused recent New Zealand glacier advances in a period of global warming

    Science.gov (United States)

    Mackintosh, Andrew N.; Anderson, Brian M.; Lorrey, Andrew M.; Renwick, James A.; Frei, Prisco; Dean, Sam M.

    2017-01-01

    Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans. PMID:28195582

  20. Regional cooling caused recent New Zealand glacier advances in a period of global warming

    Science.gov (United States)

    Mackintosh, Andrew N.; Anderson, Brian M.; Lorrey, Andrew M.; Renwick, James A.; Frei, Prisco; Dean, Sam M.

    2017-02-01

    Glaciers experienced worldwide retreat during the twentieth and early twenty first centuries, and the negative trend in global glacier mass balance since the early 1990s is predominantly a response to anthropogenic climate warming. The exceptional terminus advance of some glaciers during recent global warming is thought to relate to locally specific climate conditions, such as increased precipitation. In New Zealand, at least 58 glaciers advanced between 1983 and 2008, and Franz Josef and Fox glaciers advanced nearly continuously during this time. Here we show that the glacier advance phase resulted predominantly from discrete periods of reduced air temperature, rather than increased precipitation. The lower temperatures were associated with anomalous southerly winds and low sea surface temperature in the Tasman Sea region. These conditions result from variability in the structure of the extratropical atmospheric circulation over the South Pacific. While this sequence of climate variability and its effect on New Zealand glaciers is unusual on a global scale, it remains consistent with a climate system that is being modified by humans.

  1. A SUBSTANTIAL MASS OF COOL, METAL-ENRICHED GAS SURROUNDING THE PROGENITORS OF MODERN-DAY ELLIPTICALS

    Energy Technology Data Exchange (ETDEWEB)

    Prochaska, J. Xavier [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Hennawi, Joseph F. [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69115 Heidelberg (Germany); Simcoe, Robert A. [MIT-Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2013-01-10

    The hosts of luminous z {approx} 2 quasars evolve into today's massive elliptical galaxies. Current theories predict that the circumgalactic medium (CGM) of these massive, dark matter halos (M{sub DM} {approx} 10{sup 12.5} M{sub Sun }) should be dominated by a T {approx} 10{sup 7} K virialized plasma. We test this hypothesis with observations of 74 close-projected quasar pairs, using spectra of the background QSO to characterize the CGM of the foreground one. Surprisingly, our measurements reveal a cool (T Almost-Equal-To 10{sup 4} K), massive (M{sub CGM} > 10{sup 10} M{sub Sun }), and metal-enriched (Z {approx}> 0.1 Z{sub Sun }) medium extending to at least the expected virial radius (r{sub vir} = 160 kpc). The average equivalent widths of H I Ly{alpha} (W-bar{sub Ly{alpha}}= 2.1{+-}0.15 A for impact parameters R < 200 kpc) and C II 1334 (W-bar{sub 1334}= 0.7{+-}0.1) exceed the corresponding CGM measurements of these transitions from all galaxy populations studied previously. Furthermore, we conservatively estimate that the quasar CGM has a 64{sup +6}{sub -7}% covering fraction of optically thick gas (N{sub HI} > 10{sup 17.2} cm{sup -2}) within r{sub vir}; this covering factor is twice that of the contemporaneous Lyman break galaxy population. This unexpected reservoir of cool gas is rarely detected 'down-the-barrel' to quasars, and hence it is likely that our background sight lines intercept gas that is shadowed from the quasar ionizing radiation by the same obscuring medium often invoked in models of active galactic nucleus unification. Because the high-z halos inhabited by quasars predate modern groups and clusters, these observations are also relevant to the formation and enrichment history of the intragroup/intracluster medium.

  2. The Effect of Protoplanetary Disk Cooling Times on the Formation of Gas Giant Planets by Gravitational Instability

    Science.gov (United States)

    Boss, Alan P.

    2017-02-01

    Observational evidence exists for the formation of gas giant planets on wide orbits around young stars by disk gravitational instability, but the roles of disk instability and core accretion for forming gas giants on shorter period orbits are less clear. The controversy extends to population synthesis models of exoplanet demographics and to hydrodynamical models of the fragmentation process. The latter refers largely to the handling of radiative transfer in three-dimensional (3D) hydrodynamical models, which controls heating and cooling processes in gravitationally unstable disks, and hence dense clump formation. A suite of models using the β cooling approximation is presented here. The initial disks have masses of 0.091 M ⊙ and extend from 4 to 20 au around a 1 M ⊙ protostar. The initial minimum Toomre Q i values range from 1.3 to 2.7, while β ranges from 1 to 100. We show that the choice of Q i is equal in importance to the β value assumed: high Q i disks can be stable for small β, when the initial disk temperature is taken as a lower bound, while low Q i disks can fragment for high β. These results imply that the evolution of disks toward low Q i must be taken into account in assessing disk fragmentation possibilities, at least in the inner disk, i.e., inside about 20 au. The models suggest that if low Q i disks can form, there should be an as yet largely undetected population of gas giants orbiting G dwarfs between about 6 au and 16 au.

  3. An Advanced Option for Sodium Cooled TRU Burner Loaded with Uranium-Free Fuels

    Energy Technology Data Exchange (ETDEWEB)

    You, WuSeung; Hong, Ser Gi [Kyung Hee University, Yongin (Korea, Republic of)

    2015-05-15

    The sodium cooled fast reactors of this kind that are called burners are designed to have low conversion ratio by reducing fuel volume fraction or reducing neutron leakage or increasing neutron absorption. However, the typical SFR burners have a limited ability of TRU burning rate due to the fact that they use metallic or oxide fuels containing fertile nuclides such as {sup 238}U and {sup 232}Th and these fertile nuclides generate fissile nuclides through neutron capture even if they are designed to have low conversion ratio (e.g., 0.6). To further enhance the TRU burning rate, the removal of the fertile nuclides from the initial fuels is required and it will accelerate the reduction of TRUs that are accumulated in storages of LWR spent fuels. However, it has been well-known 4 that the removals of the fertile nuclides from the fuel degrade the inherent safety of the SFR burner cores through the significant decrease of the fuel Doppler effect, the increase of sodium void reactivity worth, and reduction of delayed neutron fraction. In this work, new option for the sodium cooled fast TRU burner cores loaded with fertile-free metallic fuels was proposed and the new cores were designed by using the suggested option. The cores were designed to enhance the inherent safety characteristics by using axially central absorber region and 6 or 12 ZrH1.8 moderator rods per fuel assembly. For each option, we considered two different types of fertile-free ternary metallic fuel (i.e., TRU-W-10Zr and TRU-Ni-10Zr). Also, we performed the BOR (Balance of Reactivity) analyses to show the self-controllability under ATWS as a measure of inherent safety. The core performance analysis showed that the new cores using axially central absorber region substantially improve the core performance parameters such as burnup reactivity swing and sodium void reactivity worth.

  4. Advanced CD-SEM metrology for qualification of DSA patterns using coordinated line epitaxy (COOL) process

    Science.gov (United States)

    Kato, Takeshi; Konishi, Junko; Ikota, Masami; Yamaguchi, Satoru; Seino, Yuriko; Sato, Hironobu; Kasahara, Yusuke; Azuma, Tsukasa

    2016-03-01

    Directed self-assembly (DSA) applying chemical epitaxy is one of the promising lithographic solutions for next generation semiconductor device manufacturing. Especially, DSA lithography using coordinated line epitaxy (COOL) process is obviously one of candidates which could be the first generation of DSA applying PS-b-PMMA block copolymer (BCP) for sub-15nm dense line patterning . DSA can enhance the pitch resolutions, and can mitigate CD errors to the values much smaller than those of the originally exposed guiding patterns. On the other hand, local line placement error often results in a worse value, with distinctive trends depending on the process conditions. To address this issue, we introduce an enhanced measurement technology of DSA line patterns with distinguishing their locations in order to evaluate nature of edge placement and roughness corresponding to individual pattern locations by using images of CD-SEM. Additionally correlations among edge roughness of each line and each space are evaluated and discussed. This method can visualize features of complicated roughness easily to control COOL process. As a result, we found the followings. (1) Line placement error and line placement roughness of DSA were slightly different each other depending on their relative position to the chemical guide patterns. (2) In middle frequency area of PSD (Power Spectral Density) analysis graphs, it was observed that shapes were sensitively changed by process conditions of chemical stripe guide size and anneals temperature. (3) Correlation coefficient analysis using PSD was able to clarify characteristics of latent defect corresponding to physical and chemical property of BCP materials.

  5. Advanced Liquid Cooling for a Traction Drive Inverter Using Jet Impingement and Microfinned Enhanced Surfaces: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S. K.; Narumanchi, S.; Mihalic, M.; Moreno, G.; Bennion, K.; Jeffers, J.

    2014-08-01

    Jet impingement on plain and micro-finned enhanced surfaces was compared to a traditional channel flow configuration. The jets provide localized cooling to areas heated by the insulated-gate bipolar transistor and diode devices. Enhanced microfinned surfaces increase surface area and thermal performance. Using lighter materials and designing the fluid path to manage pressure losses increases overall performance while reducing weight, volume, and cost. Powering four diodes in the center power module of the inverter and computational fluid dynamics (CFD) modeling was used to characterize the baseline as well as jet-impingement-based heat exchangers. CFD modeling showed the thermal performance improvements should hold for a fully powered inverter. Increased thermal performance was observed for the jet-impingement configurations when tested at full inverter power (40 to 100 kW output power) on a dynamometer. The reliability of the jets and enhanced surfaces over time was also investigated. Experimentally, the junction-to- coolant thermal resistance was reduced by up to 12.5% for jet impingement on enhanced surfaces s compared to the baseline channel flow configuration. Base plate-to-coolant (convective) resistance was reduced by up to 37.0% for the jet-based configuration compared to the baseline, suggesting that while improvements to the cooling side reduce overall resistance, reducing the passive stack resistance may contribute to lowering overall junction-to-coolant resistance. Full inverter power testing showed reduced thermal resistance from the middle of the module baseplate to coolant of up to 16.5%. Between the improvement in thermal performance and pumping power, the coefficient of performance improved by up to 13% for the jet-based configuration.

  6. Pre-Conceptual Design of a Fluoride-Salt-Cooled Small Modular Advanced High Temperature Reactor (SmAHTR)

    Energy Technology Data Exchange (ETDEWEB)

    Greene, Sherrell R [ORNL; Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Carbajo, Juan J [ORNL; Ilas, Dan [ORNL; Cisneros, Anselmo T [ORNL; Varma, Venugopal Koikal [ORNL; Corwin, William R [ORNL; Wilson, Dane F [ORNL; Yoder Jr, Graydon L [ORNL; Qualls, A L [ORNL; Peretz, Fred J [ORNL; Flanagan, George F [ORNL; Clayton, Dwight A [ORNL; Bradley, Eric Craig [ORNL; Bell, Gary L [ORNL; Hunn, John D [ORNL; Pappano, Peter J [ORNL; Cetiner, Sacit M [ORNL

    2011-02-01

    This document presents the results of a study conducted at Oak Ridge National Laboratory during 2010 to explore the feasibility of small modular fluoride salt-cooled high temperature reactors (FHRs). A preliminary reactor system concept, SmATHR (for Small modular Advanced High Temperature Reactor) is described, along with an integrated high-temperature thermal energy storage or salt vault system. The SmAHTR is a 125 MWt, integral primary, liquid salt cooled, coated particle-graphite fueled, low-pressure system operating at 700 C. The system employs passive decay heat removal and two-out-of-three , 50% capacity, subsystem redundancy for critical functions. The reactor vessel is sufficiently small to be transportable on standard commercial tractor-trailer transport vehicles. Initial transient analyses indicated the transition from normal reactor operations to passive decay heat removal is accomplished in a manner that preserves robust safety margins at all times during the transient. Numerous trade studies and trade-space considerations are discussed, along with the resultant initial system concept. The current concept is not optimized. Work remains to more completely define the overall system with particular emphasis on refining the final fuel/core configuration, salt vault configuration, and integrated system dynamics and safety behavior.

  7. Advanced Hydraulic Fracturing Technology for Unconventional Tight Gas Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Stephen Holditch; A. Daniel Hill; D. Zhu

    2007-06-19

    The objectives of this project are to develop and test new techniques for creating extensive, conductive hydraulic fractures in unconventional tight gas reservoirs by statistically assessing the productivity achieved in hundreds of field treatments with a variety of current fracturing practices ranging from 'water fracs' to conventional gel fracture treatments; by laboratory measurements of the conductivity created with high rate proppant fracturing using an entirely new conductivity test - the 'dynamic fracture conductivity test'; and by developing design models to implement the optimal fracture treatments determined from the field assessment and the laboratory measurements. One of the tasks of this project is to create an 'advisor' or expert system for completion, production and stimulation of tight gas reservoirs. A central part of this study is an extensive survey of the productivity of hundreds of tight gas wells that have been hydraulically fractured. We have been doing an extensive literature search of the SPE eLibrary, DOE, Gas Technology Institute (GTI), Bureau of Economic Geology and IHS Energy, for publicly available technical reports about procedures of drilling, completion and production of the tight gas wells. We have downloaded numerous papers and read and summarized the information to build a database that will contain field treatment data, organized by geographic location, and hydraulic fracture treatment design data, organized by the treatment type. We have conducted experimental study on 'dynamic fracture conductivity' created when proppant slurries are pumped into hydraulic fractures in tight gas sands. Unlike conventional fracture conductivity tests in which proppant is loaded into the fracture artificially; we pump proppant/frac fluid slurries into a fracture cell, dynamically placing the proppant just as it occurs in the field. From such tests, we expect to gain new insights into some of the critical

  8. An Analysis of Methanol and Hydrogen Production via High-Temperature Electrolysis Using the Sodium Cooled Advanced Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Shannon M. Bragg-Sitton; Richard D. Boardman; Robert S. Cherry; Wesley R. Deason; Michael G. McKellar

    2014-03-01

    Integration of an advanced, sodium-cooled fast spectrum reactor into nuclear hybrid energy system (NHES) architectures is the focus of the present study. A techno-economic evaluation of several conceptual system designs was performed for the integration of a sodium-cooled Advanced Fast Reactor (AFR) with the electric grid in conjunction with wind-generated electricity. Cases in which excess thermal and electrical energy would be reapportioned within an integrated energy system to a chemical plant are presented. The process applications evaluated include hydrogen production via high temperature steam electrolysis and methanol production via steam methane reforming to produce carbon monoxide and hydrogen which feed a methanol synthesis reactor. Three power cycles were considered for integration with the AFR, including subcritical and supercritical Rankine cycles and a modified supercritical carbon dioxide modified Brayton cycle. The thermal efficiencies of all of the modeled power conversions units were greater than 40%. A thermal efficiency of 42% was adopted in economic studies because two of the cycles either performed at that level or could potentially do so (subcritical Rankine and S-CO2 Brayton). Each of the evaluated hybrid architectures would be technically feasible but would demonstrate a different internal rate of return (IRR) as a function of multiple parameters; all evaluated configurations showed a positive IRR. As expected, integration of an AFR with a chemical plant increases the IRR when “must-take” wind-generated electricity is added to the energy system. Additional dynamic system analyses are recommended to draw detailed conclusions on the feasibility and economic benefits associated with AFR-hybrid energy system operation.

  9. Geothermal Energy Production from Oil/Gas Wells and Application for Building Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Honggang [Rutgers University; Liu, Xiaobing [ORNL

    2016-01-01

    One significant source of low-temperature geothermal energy is the coproduced hot water from oil/gas field production. In the United States, daily oil production has reached above 8 million barrels in recent years. Considering various conditions of wells, 5-10 times or more water can be coproduced in the range of temperature 120 F to 300 F. Like other geothermal resources, such energy source from oil/gas wells is under-utilized for its typical long distance from consumption sites. Many oil/gas fields, however, are relatively close (less than 10 miles) to consumers around cities. For instance, some petroleum fields in Pennsylvania are only a few miles away from the towns in Pittsburg area and some fields in Texas are quite close to Houston. In this paper, we evaluate geothermal potential from oil/gas wells by conducting numerical simulation and analysis of a fractured oil well in Hastings West field, Texas. The results suggest that hot water can be continuously coproduced from oil wells at a sufficient rate (about 4000 gallons/day from one well) for more than 100 years. Viable use of such geothermal source requires economical transportation of energy to consumers. The recently proposed two-step geothermal absorption (TSGA) system provides a promising energy transport technology that allows large-scale use of geothermal energy from thousands of oil/gas wells.

  10. A review of existing gas-cooled reactor circulators with application of the lessons learned to the new production reactor circulators

    Energy Technology Data Exchange (ETDEWEB)

    White, L.S.

    1990-07-01

    This report presents the results of a study of the lessons learned during the design, testing, and operation of gas-cooled reactor coolant circulators. The intent of this study is to identify failure modes and problem areas of the existing circulators so this information can be incorporated into the design of the circulators for the New Production Reactor (NPR)-Modular High-Temperature Gas Cooled Reactor (MHTGR). The information for this study was obtained primarily from open literature and includes data on high-pressure, high-temperature helium test loop circulators as well as the existing gas cooled reactors worldwide. This investigation indicates that trouble free circulator performance can only be expected when the design program includes a comprehensive prototypical test program, with the results of this test program factored into the final circulator design. 43 refs., 7 tabs.

  11. Formation of van der Waals molecules in buffer-gas-cooled magnetic traps [corrected].

    Science.gov (United States)

    Brahms, N; Tscherbul, T V; Zhang, P; Kłos, J; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-07-16

    We predict that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10(12)  cm(-3). We explore the spin relaxation of these molecules in buffer-gas-loaded magnetic traps and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T(-6) thermal dependence of the spin-change rate of silver (Ag) trapped in dense (3)He is accounted for by the formation and spin change of Ag(3)He van der Waals molecules, thus providing indirect evidence for molecular formation in a buffer-gas trap.

  12. Development of an evaluation method of fission product release fraction from High Temperature Gas-cooled Reactor fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sawa, Kazuhiro; Minato, Kazuo; Fukuda, Kousaku [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-11-01

    The High Temperature Gas-cooled Reactor (HTGR) uses coated particles as fuel. Current coated particle is a microsphere of fuel kernel with TRISO coatings. The TRISO coatings consist of a low-density, porous pyrolytic carbon (PyC) buffer layer adjacent to the spherical fuel kernel, followed by an inner isotropic PyC layer, a SiC layer and a final (outer) PyC layer. An evaluation method of fission product release behavior during the normal operation was developed. Key issues of fission gas release model were: (1) fission gas releases from matrix contamination uranium and through-coatings failed particle were separately modeled and (2) burnup and fast neutron irradiation effects were newly considered. For metallic fission product, fractional release of cesium from coated fuel particles was investigated by comparing measured data in an irradiation test which contained three kinds of fuel particles; artificially bored particles simulating through-coatings failed particles, as-manufactured SiC-failed particles and intact particles. Through the comparison of measured and calculated fractional releases, an equivalent diffusion coefficient of SiC layer in the SiC-failed particle was introduced. This report describes the developed model together with validation result of the release model. (author)

  13. Field monitoring and evaluation of a residential gas-engine-driven heat pump: Volume 1, Cooling season

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J.D.

    1995-09-01

    The Federal government is the largest single energy consumer in the United States; consumption approaches 1.5 quads/year of energy (1 quad = 10{sup 15} Btu) at a cost valued at nearly $10 billion annually. The US Department of Energy (DOE) Federal Energy Management Program (FEMP) supports efforts to reduce energy use and associated expenses in the Federal sector. One such effort, the New Technology Demonstration Program (NTDP), seeks to evaluate new energy-saving US technologies and secure their more timely adoption by the US government. Pacific Northwest Laboratory (PNL)is one of four DOE national multiprogram laboratories that participate in the NTDP by providing technical expertise and equipment to evaluate new, energy-saving technologies being studied and evaluated under that program. This two-volume report describes a field evaluation that PNL conducted for DOE/FEMP and the US Department of Defense (DoD) Strategic Environmental Research and Development Program (SERDP) to examine the performance of a candidate energy-saving technology -- a gas-engine-driven heat pump. The unit was installed at a single residence at Fort Sam Houston, a US Army base in San Antonio, Texas, and the performance was monitored under the NTDP. Participating in this effort under a Cooperative Research and Development Agreement (CRADA) were York International, the heat pump manufacturer, Gas Research Institute (GRI), the technology developer; City Public Service of San Antonio, the local utility; American Gas Cooling Center (AGCC); Fort Sam Houston; and PNL.

  14. Soil greenhouse gas emissions reduce the contribution of mangrove plants to the atmospheric cooling effect

    Science.gov (United States)

    Chen, Guangcheng; Chen, Bin; Yu, Dan; Tam, Nora F. Y.; Ye, Yong; Chen, Shunyang

    2016-12-01

    Mangrove soils have been recognized as sources of greenhouse gases, but the atmospheric fluxes are poorly characterized, and their adverse warming effect has rarely been considered with respect to the potential contribution of mangrove wetlands to climate change mitigation. The current study balanced the warming effect of soil greenhouse gas emissions with the plant carbon dioxide (CO2) sequestration rate derived from the plants’ net primary production in a productive mangrove wetland in South China to assess the role of mangrove wetlands in reducing the atmospheric warming effect. Soil characteristics were also studied in the summer to examine their relationships with gas fluxes. The soil to atmosphere fluxes of nitrous oxide (N2O), methane (CH4) and CO2 ranged from -1.6 to 50.0 μg m-2 h-1, from -1.4 to 5360.1 μg m-2 h-1 and from -31 to 512 mg m-2 h-1, respectively, which indicated that the mangrove soils act as sources of greenhouse gases in this area. The gas fluxes were higher in summer than in the cold seasons and were variable across mangrove sites. Gas fluxes in summer were positively correlated with the soil organic carbon, total nitrogen, and ammonia contents. The mangrove plants sequestered a considerable amount of atmospheric CO2 at rates varying from 3652 to 7420 g CO2 m-2 yr-1. The ecosystem acted as a source of CH4 and N2O gases but was a more intense CO2 sink. However, the warming effect of soil gas emissions accounted for 9.3-32.7% of the plant CO2 sequestration rate, partially reducing the benefit of mangrove plants, and the two trace gases comprised 9.7-33.2% of the total warming effect. We therefore propose that an assessment of the reduction of atmospheric warming effects by a mangrove ecosystem should consider both soil greenhouse gas emissions and plant CO2 sequestration.

  15. CFD simulations of moderator flow inside Calandria of the Passive Moderator Cooling System of an advanced reactor

    Energy Technology Data Exchange (ETDEWEB)

    Pal, Eshita [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094 (India); Kumar, Mukesh [Reactor Engineering Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Joshi, Jyeshtharaj B., E-mail: jbjoshi@gmail.com [Homi Bhabha National Institute, Anushaktinagar, Mumbai 400 094 (India); Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400019 India (India); Nayak, Arun K. [Reactor Engineering Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India); Vijayan, Pallippattu K., E-mail: vijayanp@barc.gov.in [Reactor Engineering Division, Bhabha Atomic Research Center, Trombay, Mumbai 400 085 (India)

    2015-10-15

    Highlights: • CFD simulations in the Calandria of an advanced reactor under natural circulation. • Under natural convection, majority of the flow recirculates within the Calandria. • Maximum temperature is located at the top and center of the fuel channel matrix. • During SBO, temperature inside Calandria is stratified. - Abstract: Passive systems are being examined for the future Advanced Nuclear Reactor designs. One of such concepts is the Passive Moderator Cooling System (PMCS), which is designed to remove heat from the moderator in the Calandria vessel passively in case of an extended Station Black Out condition. The heated heavy-water moderator (due to heat transferred from the Main Heat Transport System (MHTS) and thermalization of neutrons and gamma from radioactive decay of fuel) rises upward due to buoyancy, gets cooled down in a heat exchanger and returns back to Calandria, completing a natural circulation loop. The natural circulation should provide sufficient cooling to prevent the increase of moderator temperature and pressure beyond safe limits. In an earlier study, a full-scale 1D transient simulation was performed for the reactor including the MHTS and the PMCS, in the event of a station blackout scenario (Kumar et al., 2013). The results indicate that the systems remain within the safe limits for 7 days. However, the flow inside a geometry like Calandria is quite complex due to its large size and inner complexities of dense fuel channel matrix, which was simplified as a 1D pipe flow in the aforesaid analysis. In the current work, CFD simulations are performed to study the temperature distributions and flow distribution of moderator inside the Calandria vessel using a three-dimensional CFD code, OpenFoam 2.2.0. First, a set of steady state simulation was carried out for a band of inlet mass flow rates, which gives the minimum mass flow rate required for removing the maximum heat load, by virtue of prediction of hot spots inside the Calandria

  16. Fuel economy screening study of advanced automotive gas turbine engines

    Science.gov (United States)

    Klann, J. L.

    1980-01-01

    Fuel economy potentials were calculated and compared among ten turbomachinery configurations. All gas turbine engines were evaluated with a continuously variable transmission in a 1978 compact car. A reference fuel economy was calculated for the car with its conventional spark ignition piston engine and three speed automatic transmission. Two promising engine/transmission combinations, using gasoline, had 55 to 60 percent gains over the reference fuel economy. Fuel economy sensitivities to engine design parameter changes were also calculated for these two combinations.

  17. A History of Dosimetry for the Advanced Gas-cooled Reactors

    Directory of Open Access Journals (Sweden)

    Shaw Simon

    2016-01-01

    Full Text Available This paper presents a summary of the methods used in the first ∼40 years of AGR neutron dosimetry and nuclear heating calculations, and the influence of the earlier Magnox reactor dosimetry programme. While the current state-of-the-art Monte Carlo methods are extremely powerful they still require very careful consideration of the quality of the input data, nuclear data validation and variance reduction techniques; in particular, this paper examines the difficulties in assuring the adequate convergence of calculations when Monte Carlo acceleration is applied in the presence of significant streaming paths through attenuating or scattering media.

  18. A History of Dosimetry for the Advanced Gas-cooled Reactors

    Science.gov (United States)

    Shaw, Simon; Thornton, Dean

    2016-02-01

    This paper presents a summary of the methods used in the first ˜40 years of AGR neutron dosimetry and nuclear heating calculations, and the influence of the earlier Magnox reactor dosimetry programme. While the current state-of-the-art Monte Carlo methods are extremely powerful they still require very careful consideration of the quality of the input data, nuclear data validation and variance reduction techniques; in particular, this paper examines the difficulties in assuring the adequate convergence of calculations when Monte Carlo acceleration is applied in the presence of significant streaming paths through attenuating or scattering media.

  19. Final report for the Advanced Natural Gas Vehicle Project

    Energy Technology Data Exchange (ETDEWEB)

    John Wozniak

    1999-02-16

    The project objective was to develop the technologies necessary to prototype a dedicated compressed natural gas (CNG) powered, mid-size automobile with operational capabilities comparable to gasoline automobiles. A system approach was used to design and develop the engine, gas storage system and vehicle packaging. The 2.4-liter DOHC engine was optimized for natural gas operation with high-compression pistons, hardened exhaust valves, a methane-specific catalytic converter and multi-point gaseous injection. The chassis was repackaging to increase space for fuel storage with a custom-designed, cast-aluminum, semi-trailing arm rear suspension system, a revised flat trunk sheet-metal floorpan and by equipping the car with run-flat tires. An Integrated Storage system (ISS) was developed using all-composite, small-diameter cylinders encapsulated within a high-strength fiberglass shell with impact-absorbing foam. The prototypes achieved the target goals of a city/highway driving range of 300 miles, ample trunk capacity, gasoline vehicle performance and ultra low exhaust emissions.

  20. A Computational Study for the Utilization of Jet Pulsations in Gas Turbine Film Cooling and Flow Control

    Science.gov (United States)

    Kartuzova, Olga V.

    2012-01-01

    This report is the second part of a three-part final report of research performed under an NRA cooperative Agreement contract. The first part is NASA/CR-2012-217415. The third part is NASA/CR-2012-217417. Jets have been utilized in various turbomachinery applications in order to improve gas turbines performance. Jet pulsation is a promising technique because of the reduction in the amount of air removed from compressor. In this work two areas of pulsed jets applications were computationally investigated using the commercial code Fluent (ANSYS, Inc.); the first one is film cooling of High Pressure Turbine (HPT) blades and second one is flow separation control over Low Pressure Turbine (LPT) airfoil using Vortex Generator Jets (VGJ). Using pulsed jets for film cooling purposes can help to improve the effectiveness and thus allow higher turbine inlet temperature. Effects of the film hole geometry, blowing ratio and density ratio of the jet, pulsation frequency and duty cycle of blowing on the film cooling effectiveness were investigated. As for the low-pressure turbine (LPT) stages, the boundary layer separation on the suction side of airfoils can occur due to strong adverse pressure gradients. The problem is exacerbated as airfoil loading is increased. Active flow control could provide a means for minimizing separation under conditions where it is most severe (low Reynolds number), without causing additional losses under other conditions (high Reynolds number). The effects of the jet geometry, blowing ratio, density ratio, pulsation frequency and duty cycle on the size of the separated region were examined in this work. The results from Reynolds Averaged Navier-Stokes and Large Eddy Simulation computational approaches were compared with the experimental data.

  1. THE DIFFERENT EVOLUTION OF GAS AND DUST IN DISKS AROUND SUN-LIKE AND COOL STARS

    NARCIS (Netherlands)

    Pascucci, I.; Apai, D.; Luhman, K.; Henning, Th.; Bouwman, J.; Meyer, M. R.; Lahuis, F.; Natta, A.

    2009-01-01

    Planet formation is profoundly impacted by the properties of protoplanetary disks and their central star. However, how disk properties vary with stellar parameters remains poorly known. Here, we present the first comprehensive, comparative Spitzer/IRS study of the dust and gas properties of disks ar

  2. Assessment of coal gasification/hot gas cleanup based advanced gas turbine systems

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-01

    The major objectives of the joint SCS/DOE study of air-blown gasification power plants with hot gas cleanup are to: (1) Evaluate various power plant configurations to determine if an air-blown gasification-based power plant with hot gas cleanup can compete against pulverized coal with flue gas desulfurization for baseload expansion at Georgia Power Company's Plant Wansley; (2) determine if air-blown gasification with hot gas cleanup is more cost effective than oxygen-blown IGCC with cold gas cleanup; (3) perform Second-Law/Thermoeconomic Analysis of air-blown IGCC with hot gas cleanup and oxygen-blown IGCC with cold gas cleanup; (4) compare cost, performance, and reliability of IGCC based on industrial gas turbines and ISTIG power island configurations based on aeroderivative gas turbines; (5) compare cost, performance, and reliability of large (400 MW) and small (100 to 200 MW) gasification power plants; and (6) compare cost, performance, and reliability of air-blown gasification power plants using fluidized-bed gasifiers to air-blown IGCC using transport gasification and pressurized combustion.

  3. Design Study of 200MWth Gas Cooled Fast Reactor with Nitride (UN-PuN Fuel Long Life without Refueling

    Directory of Open Access Journals (Sweden)

    Syarifah Ratna Dewi

    2016-01-01

    Full Text Available Design study of 200 MWth Gas Cooled Fast Reactor with UN-PuN fuel long life without refueling has been done. GFR is one type reactor in Generation IV reactor system. It uses helium coolant and fast neutron spectrum. Helium is chemical inert, single phase and low neutron moderation. In this study the calculations are performed by using SRAC code with PIJ calculation for the fuel pin cell calculation and CITATION calculation for core calculation. The data libraries use JENDL 3.2. The variation fuel fractions are 50% until 60%. The diameter active core is 150 cm and the height active core is 100 cm. The reflector radial-axial width is 50 cm. The variation of the powers are 100 MWth up to 500 MWth. The high power causes the high k-eff value. The optimum design is reached when the power is 200 MWth, variation percentage Plutonium for fuel F1:F2:F3=9%:11%:13%. The comparation of fuel:cladding:coolant fraction = 55%:10%:35%. The cooling down time of Plutonium is nine months. The optimum k-eff value is 1.0142 with excess reactivity value 1.403%. The decay of Plutonium decrease k-eff value in the beginning of burn up.

  4. Analysis on thermophoretic deposit of fine particle on water wall of 10 MW high temperature gas-cooled reactor

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tao; YANG Rui-Chang; JIA Dou-Nan

    2005-01-01

    The water wall is an important part of the passive natural circulation residual heat removal system in a high temperature gas-cooled reactor. The maximum temperatures of the pressure shell and the water wall are calculated using annular vertical closed cavity model. Fine particles can deposit on the water wall due to the thermophore sis effect. This deposit can affect heat transfer. The thermophoretic deposit efficiency is calculated by using Batch and Shen's formula fitted for both laminar flow and turbulent flow. The calculated results indicate that natural convection is turbulent in the closed cavity. The transient thermophoretic deposit efficiency rises with the increase of the pressure shell's temperature. Its maximum value is 14%.

  5. Analysis of two-phase flow instability in helical tube steam generator in high temperature gas cooled reactor

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yu; Lv, Xuefeng; Wang, Shengfei; Niu, Fenglei; Tian, Li [North China Electric Power Univ., Beijing (Switzerland)

    2012-03-15

    The steam generator composed of multi-helical tubes is used in high temperature gas cooled reactors and two-phase flow instability should be avoided in design. And density-wave oscillation which is mainly due to flow, density and the relationship between the pressure drop delays and feedback effects is one of the two-phase flow instability phenomena easily to occur. Here drift-flux model is used to simulate the performance of the fluid in the secondary side and frequency domain and time domain methods are used to evaluate whether the density-wave oscillation will happen or not. Several operating conditions with nominal power from 15% to 30% are calculated in this paper. The results of the two methods are in accordance, flow instability will occur when power is less than 20% nominal power, which is also according with the result of the experiments well.

  6. Studies on disintegrating spherical fuel elements of high temperature gas-cooled reactor by a electrochemical method

    Science.gov (United States)

    Tian, Lifang; Wen, Mingfen; Chen, Jing

    2013-01-01

    Spherical fuel elements of a high temperature gas-cooled reactor were disintegrated through a electrochemical method with NaNO3 as electrolyte. The X-ray diffraction spectra and total carbon contents of the graphite fragments were determined, and the results agreed with those from simulated fuel elements. After conducting the characterization analysis and the leaching experiment of coated fuel particles, the uranium concentrations of leaching solutions and spent electrolyte were found to be at background levels. The results demonstrate the effectiveness of the improved electrochemical method with NaNO3 as electrolyte in disintegrating the unirradiated fuel elements without any damage to the coated fuel particles. Moreover, the method avoided unexpected radioactivity contamination to the graphite matrix and spent electrolyte.

  7. Safety assessment for electricity generation failure accident of gas cooled nuclear power plant using system dynamics (SD) method

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Tae Ho [Seoul National Univ. (Korea, Republic of). Dept. of Nuclear Engineering

    2013-04-15

    The power production failure happens in the loss of coolant of the nuclear power plants (NPPs). The air ingress is a serious accident in gas cooled NPPs. The quantification of the study performed by the system dynamics (SD) method which is processed by the feedback algorithms. The Vensim software package is used for the simulation, which is performed by the Monte-Carlo method. Two kinds of considerations as the economic and safety properties are important in NPPs. The result shows the stability of the operation when the power can be decided. The maximum value of risk is the 11.77 in 43rd and the minimum value is 0.0 in several years. So, the success of the circulation of coolant is simulated by the dynamical values. (orig.)

  8. CFD Analysis of Turbulent Flow Phenomena in the Lower Plenum of a Prismatic Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    T. Gallaway; S.P. Antal; M.Z. Podowski; D.P. Guillen

    2007-09-01

    This paper is concerned with the implementation of a computational model of turbulent flow in a section of the lower plenum of Very High Temperature Reactor (VHTR). The proposed model has been encoded in a state-of-the-art CFD code, NPHASE. The results of NPHASE predictions have been compared against the experimental data collected using a scaled model of a sub-region in the lower plenum of a modular prismatic gas-cooled reactor. It has been shown that the NPHASE-based model is capable of predicting a three-dimensional velocity field in a complex geometrical configuration of VHTR lower plenum. The current and future validations of computational predictions are necessary for design and analysis of new reactor concepts, as well as for safety analysis and licensing calculations.

  9. Design Study of Modular Nuclear Power Plant with Small Long Life Gas Cooled Fast Reactors Utilizing MOX Fuel

    Science.gov (United States)

    Ilham, Muhammad; Su’ud, Zaki

    2017-01-01

    Growing energy needed due to increasing of the world’s population encourages development of technology and science of nuclear power plant in its safety and security. In this research, it will be explained about design study of modular fast reactor with helium gas cooling (GCFR) small long life reactor, which can be operated over 20 years. It had been conducted about neutronic design GCFR with Mixed Oxide (UO2-PuO2) fuel in range of 100-200 MWth NPPs of power and 50-60% of fuel fraction variation with cylindrical pin cell and cylindrical balance of reactor core geometry. Calculation method used SRAC-CITATION code. The obtained results are the effective multiplication factor and density value of core reactor power (with geometry optimalization) to obtain optimum design core reactor power, whereas the obtained of optimum core reactor power is 200 MWth with 55% of fuel fraction and 9-13% of percentages.

  10. Entropy generation in a channel resembling gas turbine cooling passage: Effect of rotation number and density ratio on entropy generation

    Indian Academy of Sciences (India)

    M Basha; M Al-Qahtani; B S Yilbas

    2009-06-01

    Flow into a passage resembling a gas turbine blade cooling passage is considered and entropy generation rate in the passage is examined for unique rotation number and density ratios. In the simulations, leading and trailing walls of the passage are assumed to be at constant temperature. A control volume approach is introduced to discretize the governing equations of flow, heat transfer, and entropy generation. Reynolds stress turbulence model is accommodated in the simulation to account for the turbulence. The study is extended to include two rotational speeds and three density ratios. The passage aspect ratio is kept 10:1. It is found that volumetric entropy generation rate attains high values at passage inlet due to attainment of high temperature gradient in this region. Increasing rotation number and density ratio enhances volumetric entropy generation rate in the passage.

  11. Army Gas-Cooled Reactor Systems program: alternator final design report

    Energy Technology Data Exchange (ETDEWEB)

    1964-06-01

    The development and testing of a demonstration brushless alternator for the ML-1 mobile nuclear power plant is described. The brushless concept was selected after it became apparent that a conventional power generator could not satisfy the ML-1 weight and size requirements. The demonstration alternator fabricated and tested under this program did not meet all performance specifications; the efficiency was low and the unit could not be operated for significant periods of time without overheating. However, a large body of useful data was accumulated during the extensive development program. Of special interest are data on the rotor and stator design, the cooling requirements and on the distribution of eddy current losses. Analysis of the data indicates that a brushless alternator, only slightly larger and heavier than was specified for the ML-1, could be developed with a modest additional effort.

  12. A dense gas of laser-cooled atoms for hybrid atom-ion trapping

    Science.gov (United States)

    Höltkemeier, Bastian; Glässel, Julian; López-Carrera, Henry; Weidemüller, Matthias

    2017-01-01

    We describe the realization of a dark spontaneous-force trap of rubidium atoms. The atoms are loaded from a beam provided by a two-dimensional magneto-optical trap yielding a capture efficiency of 75%. The dense and cold atomic sample is characterized by saturated absorption imaging. Up to 10^9 atoms are captured with a loading rate of 3× 10^9 atoms/s into a cloud at a temperature of 250 μK with the density exceeding 10^{11} atoms/cm^3. Under steady-state conditions, more than 90% of the atoms can be prepared into the absolute atomic ground state, which provides favorable conditions for the investigation of sympathetic cooling of ions in a hybrid atom-ion trap.

  13. Dry cooling of power generating stations: a summary of the economic evaluation of several advanced concepts via a design optimization study and a conceptual design and cost estimate

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, B.M.; Allemann, R.T.; Faletti, D.W.; Fryer, B.C.; Zaloudek, F.R.

    1976-09-01

    Due to enhanced concern about water supplies and water use priorities, dry cooling systems for thermal power plants are receiving increased consideration, even though electric power from dry-cooled power plants currently costs 10 to 15 percent more than power from wet-cooled plants. A two-year study which analyzed the performance of existing dry-cooled systems and which developed economic and performance models for cost optimization of dry-cooled systems is reported. First, a design optimization code was used to compare the cost of a number of advanced all-dry systems. Then, 5 different dry/wet systems were carried through conceptual design and cost estimating. The results showed for either an all dry or a combination wet-and-dry cooling system, cost optimization can be achieved with an advanced system using ammonia as an intermediate heat exchange fluid (between the turbine and the dry tower), and that development of the ammonia concept should procede in order to provide performance and reliability data for the ammonia system. (LCL)

  14. Stress-optimised, steam-cooled gas turbine blade. Final report; Spannungsoptimierte, dampfgekuehlte Gasturbinenschaufel. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Kusterer, K.; Kammerer, T.; Kemper, M.; Lang, G.; Roeper, R.

    2002-07-01

    Steam cooling is a technology with a high innovation potential, so it is not surprising that intensive research is done currently especially in the USA and Japan. This project focused on the technological and constructional aspects of the technology, including thermal and thermomechanical design and calculation of a steam-cooled turbine blade as the high temperature gradients and high thermal stresses are a key problem in the implementation of this technology. This is the only EU-wide project with a technological and design-oriented approach. An interdisciplinary was chosen which includes process analysis, numeric simulations and experiments. Results so far are presented. [German] Die Technologie der Dampfkuehlung steht zur Zeit im Mittelpunkt intensiver industrieller Entwicklungsbemuehungen, insbesondere auf amerikanischer und japanischer Seite, weil das hohe Innovationspotenzial dieser Technologie erkannt worden ist. Die Motivation dieses Vorhabens beruht auf der Erkenntnis, dass die Technologie der Dampfkuehlung fuer Gasturbinen in GuD-Kraftwerken eine der Schluesseltechnologien ist, die im Hinblick auf die Wirkungsgradsteigerung der GuD-Anlagen und somit zur CO{sub 2}-Reduzierung eine wesentliche Rolle spielt. Im Vordergrund des Vorhabens stehen technologische und konstruktive Aspekte bei der Umsetzung der Dampfkuehlungstechnologie. Es sollen Erkenntnisse zu technischen Problemen sowie Loesungsansaetze hierzu erbracht werden, die fuer eine erfolgreiche Einfuehrung der innovativen Technologie notwendig sind. Damit verbunden ist die thermische und thermomechanische Auslegung und Berechnung einer dampfgekuehlten Schaufel, da insbesondere die Verbindung von hohen Temperaturgradienten und hohen thermischen Spannungen eine besondere Schwierigkeit bei der Umsetzung dieser Technologie darstellt. Die technisch-konstruktive Zielsetzung zur Umsetzung der Dampfkuehltechnologie fuer Turbinenschaufeln ist dabei im Rahmen europaeischer Forschungsanstrengungen einzigartig. Zur

  15. The Cosmic History of Hot Gas Cooling and Radio AGN Activity in Massive Early-Type Galaxies

    Science.gov (United States)

    Danielson, A. L. R.; Lehmer, B. D.; Alexander, D. M.; Brandt, W. M.; Luo, B.; Miller, N.; Xue, Y. Q.; Stott, J. P.

    2012-01-01

    We study the X-ray properties of 393 optically selected early-type galaxies (ETGs) over the redshift range of z approx equals 0.0-1.2 in the Chandra Deep Fields. To measure the average X-ray properties of the ETG population, we use X-ray stacking analyses with a subset of 158 passive ETGs (148 of which were individually undetected in X-ray). This ETG subset was constructed to span the redshift ranges of z = 0.1-1.2 in the approx equals 4 Ms CDF-S and approx equals 2 Ms CDF-N and z = 0.1-0.6 in the approx equals 250 ks E-CDF-S where the contribution from individually undetected AGNs is expected to be negligible in our stacking. We find that 55 of the ETGs are detected individually in the X-rays, and 12 of these galaxies have properties consistent with being passive hot-gas dominated systems (i.e., systems not dominated by an X-ray bright Active Galactic Nucleus; AGN). On the basis of our analyses, we find little evolution in the mean 0.5-2 keY to B-band luminosity ratio (L(sub x) /L(sub Beta) varies as [1 +z]) since z approx equals 1.2, implying that some heating mechanism prevents the gas from cooling in these systems. We consider that feedback from radio-mode AGN activity could be responsible for heating the gas. We select radio AGNs in the ETG population using their far-infrared/radio flux ratio. Our radio observations allow us to constrain the duty cycle history of radio AGN activity in our ETG sample. We estimate that if scaling relations between radio and mechanical power hold out to z approx equals 1.2 for the ETG population being studied here, the average mechanical power from AGN activity is a factor of approx equals1.4 -- 2.6 times larger than the average radiative cooling power from hot gas over the redshift range z approx equals 0-1.2. The excess of inferred AGN mechanical power from these ETGs is consistent with that found in the local Universe for similar types of galaxies.

  16. Cooling and climatisation of buildings and premises with natural gas; Kylning och klimatisering av byggnader och lokaler med hjaelp av naturgas

    Energy Technology Data Exchange (ETDEWEB)

    Lindkvist, A. [Vattenfall Energisystem AB, Stockholm (Sweden)

    1997-04-01

    Today, gas based cooling systems are not profitable in most applications. The economical assessment of natural gas climatisation is dependent of the price difference between gas and electricity. One requirement for good profitability is that the emitted heat, by the refrigeration system, is used. The costs of capital and maintenance are higher for gas based systems compared with those for electrical cooling systems. The profit also depends of the application the system is used in. The natural gas system is favoured by the low difference in temperature between the warm and the cold side of the system. There are three common techniques used for natural gas cooling purposes; the compressor system, the absorption system and the sorption system. Examples on suitable applications for natural gas cooling techniques are computer halls, super-stores, slaughter houses and bath houses. The compressor system is composed of an ordinary compressor refrigeration system powered by a gas engine. The gas engine can be either an Otto engine or a Stirling engine. The Otto engine kind is dominating the market. The absorption system is a refrigeration system using heat as energy source. Only a small amount of electricity is needed. The absorption system is less efficient than the compressor system. The sorption system is commonly used as a dehumidifier. Recently, sorption based refrigeration systems has been introduced to the market. The market volume for district cooling in Sweden 1995 was 30 GWh, which is equivalent to approximately 15 GWh natural gas. At the turn of the century the market for district cooling is estimated to reach 370 GWh/year, which is approximately equivalent to 185 GWh natural gas per year. Research in the refrigeration area is aiming towards higher efficiency with more environmentally acceptable refrigerants.The intention is to find `natural` refrigerants that will enable compressors to reach higher energy factors and that will require less maintenance. The

  17. Design and Test of Advanced Thermal Simulators for an Alkali Metal-Cooled Reactor Simulator

    Science.gov (United States)

    Garber, Anne E.; Dickens, Ricky E.

    2011-01-01

    The Early Flight Fission Test Facility (EFF-TF) at NASA Marshall Space Flight Center (MSFC) has as one of its primary missions the development and testing of fission reactor simulators for space applications. A key component in these simulated reactors is the thermal simulator, designed to closely mimic the form and function of a nuclear fuel pin using electric heating. Continuing effort has been made to design simple, robust, inexpensive thermal simulators that closely match the steady-state and transient performance of a nuclear fuel pin. A series of these simulators have been designed, developed, fabricated and tested individually and in a number of simulated reactor systems at the EFF-TF. The purpose of the thermal simulators developed under the Fission Surface Power (FSP) task is to ensure that non-nuclear testing can be performed at sufficiently high fidelity to allow a cost-effective qualification and acceptance strategy to be used. Prototype thermal simulator design is founded on the baseline Fission Surface Power reactor design. Recent efforts have been focused on the design, fabrication and test of a prototype thermal simulator appropriate for use in the Technology Demonstration Unit (TDU). While designing the thermal simulators described in this paper, effort were made to improve the axial power profile matching of the thermal simulators. Simultaneously, a search was conducted for graphite materials with higher resistivities than had been employed in the past. The combination of these two efforts resulted in the creation of thermal simulators with power capacities of 2300-3300 W per unit. Six of these elements were installed in a simulated core and tested in the alkali metal-cooled Fission Surface Power Primary Test Circuit (FSP-PTC) at a variety of liquid metal flow rates and temperatures. This paper documents the design of the thermal simulators, test program, and test results.

  18. ADVANCED SULFUR CONTROL CONCEPTS FOR HOT-GAS DESULFURIZATION TECHNOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    A. LOPEZ ORTIZ; D.P. HARRISON; F.R. GROVES; J.D. WHITE; S. ZHANG; W.-N. HUANG; Y. ZENG

    1998-10-31

    This research project examined the feasibility of a second generation high-temperature coal gas desulfurization process in which elemental sulfur is produced directly during the sorbent regeneration phase. Two concepts were evaluated experimentally. In the first, FeS was regenerated in a H2O-O2 mixture. Large fractions of the sulfur were liberated in elemental form when the H2O-O2 ratio was large. However, the mole percent of elemental sulfur in the product was always quite small (<<1%) and a process based on this concept was judged to be impractical because of the low temperature and high energy requirements associated with condensing the sulfur. The second concept involved desulfurization using CeO2 and regeneration of the sulfided sorbent, Ce2O2S, using SO2 to produce elemental sulfur directly. No significant side reactions were observed and the reaction was found to be quite rapid over the temperature range of 500°C to 700°C. Elemental sulfur concentrations (as S2) as large as 20 mol% were produced. Limitations associated with the cerium sorbent process are concentrated in the desulfurization phase. High temperature and highly reducing coal gas such as produced in the Shell gasification process are required if high sulfur removal efficiencies are to be achieved. For example, the equilibrium H2S concentration at 800°C from a Shell gas in contact with CeO2 is about 300 ppmv, well above the allowable IGCC specification. In this case, a two-stage desulfurization process using CeO2 for bulk H2S removal following by a zinc sorbent polishing step would be required. Under appropriate conditions, however, CeO2 can be reduced to non-stoichiometric CeOn (n<2) which has significantly greater affinity for H2S. Pre-breakthrough H2S concentrations in the range of 1 ppmv to 5 ppmv were measured in sulfidation tests using CeOn at 700°C in highly reducing gases, as measured by equilibrium O2 concentration, comparable to the Shell gas. Good sorbent durability was indicated in

  19. Ceramic membranes for gas separation in advanced fossil power plants

    Energy Technology Data Exchange (ETDEWEB)

    Meulenberg, W.A.; Baumann, S.; Ivanova, M.; Gestel, T. van; Bram, M.; Stoever, D. [Forschungszentrum Juelich GmbH (DE). Inst. fuer Energieforschung (IEF)

    2010-07-01

    The reduction or elimination of CO{sub 2} emissions from electricity generation power plants fuelled by coal or gas is a major target in the current socio-economic, environmental and political discussion to reduce green house gas emissions such as CO{sub 2}. This mission can be achieved by introducing gas separation techniques making use of membrane technology, which is, as a rule, associated with significantly lower efficiency losses compared with the conventional separation technologies. Depending on the kind of power plant process different membrane types (ceramic, polymer, metal) can be implemented. The possible technology routes are currently investigated to achieve the emission reduction. They rely on different separation tasks. The CO{sub 2}/N{sub 2} separation is the main target in the post-combustion process. Air separation (O{sub 2}/N{sub 2}) is the focus of the oxyfuel process. In the pre-combustion process an additional H{sub 2}/CO{sub 2} separation is included. Although all separation concepts imply different process requirements they have in common a need in membranes with high permeability, selectivity and stability. In each case CO{sub 2} is obtained in a readily condensable form. CO{sub 2}/N{sub 2} separation membranes like microporous membranes or polymer membranes are applicable in post-combustion stages. In processes with oxyfuel combustion, where the fuel is combusted with pure oxygen, oxygen transport membranes i.e. mixed ionic electronic conducting (MIEC) membranes with mainly perovskite or fluorite structure can be integrated. In the pre-combustion stages of the power plant process, H{sub 2}/CO{sub 2} separation membranes like microporous membranes e.g. doped silica or mixed protonic electronic conductors or metal membranes can be applied. The paper gives an overview about the considered ceramic materials for the different gas separation membranes. The manufacturing of bulk materials as well as supported thin films of these membranes along

  20. Gas-turbine critical research and advanced technology support project

    Science.gov (United States)

    Clark, J. S.; Lowell, C. E.; Niedzwiecki, R. W.; Nainiger, J. J.

    1979-01-01

    The technical progress made during the first 15 months of a planned 40-month project to provide a critical-technology data base for utility gas-turbine systems capable of burning coal-derived fuels is summarized. Tasks were included in the following areas: (1) combustion, to study the combustion of coal-derived fuels and conversion of fuel-bound nitrogen to NOx; (2) materials, to understand and prevent hot corrosion; and (3) system studies, to integrate and guide the other technologies. Significant progress was made.

  1. Materials Research for Advanced Inertial Instrumentation. Task 2. Gas Bearing Material Development.

    Science.gov (United States)

    1984-02-01

    AD-RA4e 435 MATERIALS RESEARCH FOR ADVANCED INERTIAL 1/i INSTRUMENTATION TASK 2 GAS BERRI..(U) CHARLES STARK DRAPER LAB INC CAMBRIDGE MR K KUMAR ET...I.25.2 - U-2 1Ŗ AmsaŚ MATERIALS RESEARCH FOR ADVANCE- INERTIAL INSTRUMENTATION TASK 2: GAS BEAR ING MATERIAL F4., FEBRUARY 1984". 414 K . KUMAR...HNEWBORN’ DAS 1 4 -r~ edfor fte Office of N w ta rdv mapch ~~ppr~vedfor public rele..; distribution ea- . . " 0*sinis granted to U.S. Govemn pr~t in

  2. Implementation of Sub-Cooling of Cryogenic Propellants by Injection of Non-condensing Gas to the Generalized Fluid Systems Simulation Program (GFSSP)

    Science.gov (United States)

    Huggett, Daniel J.; Majumdar, Alok

    2013-01-01

    Cryogenic propellants are readily heated when used. This poses a problem for rocket engine efficiency and effective boot-strapping of the engine, as seen in the "hot" LOX (Liquid Oxygen) problem on the S-1 stage of the Saturn vehicle. In order to remedy this issue, cryogenic fluids were found to be sub-cooled by injection of a warm non-condensing gas. Experimental results show that the mechanism behind the sub-cooling is evaporative cooling. It has been shown that a sub-cooled temperature difference of approximately 13 deg F below saturation temperature [1]. The phenomenon of sub-cooling of cryogenic propellants by a non-condensing gas is not readily available with the General Fluid System Simulation Program (GFSSP) [2]. GFSSP is a thermal-fluid program used to analyze a wide variety of systems that are directly impacted by thermodynamics and fluid mechanics. In order to model this phenomenon, additional capabilities had to be added to GFSSP in the form of a FORTRAN coded sub-routine to calculate the temperature of the sub-cooled fluid. Once this was accomplished, the sub-routine was implemented to a GFSSP model that was created to replicate an experiment that was conducted to validate the GFSSP results.

  3. Analytical investigation of thermal barrier coatings on advanced power generation gas turbines

    Science.gov (United States)

    Amos, D. J.

    1977-01-01

    An analytical investigation of present and advanced gas turbine power generation cycles incorporating thermal barrier turbine component coatings was performed. Approximately 50 parametric points considering simple, recuperated, and combined cycles (including gasification) with gas turbine inlet temperatures from current levels through 1644K (2500 F) were evaluated. The results indicated that thermal barriers would be an attractive means to improve performance and reduce cost of electricity for these cycles. A recommended thermal barrier development program has been defined.

  4. Cooling of Dense Gas by H2O Line Emission and an Assessment of its Effects in Chondrule-Forming Shocks

    CERN Document Server

    Morris, M A; Ciesla, F J

    2008-01-01

    We consider gas at densities appropriate to protoplanetary disks and calculate its ability to cool due to line radiation emitted by H2O molecules within the gas. Our work follows that of Neufeld & Kaufman (1993; ApJ, 418, 263), expanding on their work in several key aspects, including use of a much expanded line database, an improved escape probability formulism, and the inclusion of dust grains, which can absorb line photons. Although the escape probabilities formally depend on a complicated combination of optical depth in the lines and in the dust grains, we show that the cooling rate including dust is well approximated by the dust-free cooling rate multiplied by a simple function of the dust optical depth. We apply the resultant cooling rate of a dust-gas mixture to the case of a solar nebula shock pertinent to the formation of chondrules, millimeter-sized melt droplets found in meteorites. Our aim is to assess whether line cooling can be neglected in chondrule-forming shocks or if it must be included....

  5. Effect of RANS-Type Turbulence Models on Adiabatic Film Cooling Effectiveness over a Scaled Up Gas Turbine Blade Leading Edge Surface

    Science.gov (United States)

    Yepuri, Giridhara Babu; Talanki Puttarangasetty, Ashok Babu; Kolke, Deepak Kumar; Jesuraj, Felix

    2016-06-01

    Increasing the gas turbine inlet temperature is one of the key technologies in raising gas turbine engine power output. Film cooling is one of the efficient cooling techniques to cool the hot section components of a gas turbine engines in turn the turbine inlet temperature can be increased. This study aims at investigating the effect of RANS-type turbulence models on adiabatic film cooling effectiveness over a scaled up gas turbine blade leading edge surfaces. For the evaluation, five different two equation RANS-type turbulent models have been taken in consideration, which are available in the ANSYS-Fluent. For this analysis, the gas turbine blade leading edge configuration is generated using Solid Works. The meshing is done using ANSYS-Workbench Mesh and ANSYS-Fluent is used as a solver to solve the flow field. The considered gas turbine blade leading edge model is having five rows of film cooling circular holes, one at stagnation line and the two each on either side of stagnation line at 30° and 60° respectively. Each row has the five holes with the hole diameter of 4 mm, pitch of 21 mm arranged in staggered manner and has the hole injection angle of 30° in span wise direction. The experiments are carried in a subsonic cascade tunnel facility at heat transfer lab of CSIR-National Aerospace Laboratory with a Reynolds number of 1,00,000 based on leading edge diameter. From the Computational Fluid Dynamics (CFD) evaluation it is found that K-ɛ Realizable model gives more acceptable results with the experimental values, compared to the other considered turbulence models for this type of geometries. Further the CFD evaluated results, using K-ɛ Realizable model at different blowing ratios are compared with the experimental results.

  6. Swirling midframe flow for gas turbine engine having advanced transitions

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, Matthew D.; Charron, Richard C.; Rodriguez, Jose L.; Kusters, Bernhard W.; Morrison, Jay A.; Beeck, Alexander R.

    2016-12-27

    A gas turbine engine can-annular combustion arrangement (10), including: an axial compressor (82) operable to rotate in a rotation direction (60); a diffuser (100, 110) configured to receive compressed air (16) from the axial compressor; a plenum (22) configured to receive the compressed air from the diffuser; a plurality of combustor cans (12) each having a combustor inlet (38) in fluid communication with the plenum, wherein each combustor can is tangentially oriented so that a respective combustor inlet is circumferentially offset from a respective combustor outlet in a direction opposite the rotation direction; and an airflow guiding arrangement (80) configured to impart circumferential motion to the compressed air in the plenum in the direction opposite the rotation direction.

  7. CFD-DEM simulation of a conceptual gas-cooled fluidized bed nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Lucilla C.; Su, Jian, E-mail: lucillalmeida@gmail.com, E-mail: sujian@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Aguirre, Joao, E-mail: aguirre@rocky-dem.com [Engineering Simulation and Scientific Software (ESSS), Rio de Janeiro, RJ (Brazil)

    2015-07-01

    Several conceptual designs of the fluidized-bed nuclear reactor have been proposed due to its many advantages over conventional nuclear reactors such as PWRs and BWRs. Amongst their characteristics, the enhanced heat transfer and mixing enables a more uniform temperature distribution, reducing the risk of hot-spot and excessive fuel temperature, in addition to resulting in a higher burnup of the fuel. Furthermore, the relationship between the bed height and reactor neutronics turns the coolant flow rate control into a power production mechanism. Moreover, the possibility of removing the fuel by gravity from the movable core in case of a loss-of-cooling accident increases its safety. High-accuracy modeling of particles and coolant flow in fluidized bed reactors is needed to evaluate reliably the thermal-hydraulic efficiency and safety margin. The two-way coupling between solid and fluid can account for high-fidelity solid-solid interaction and reasonable accuracy in fluid calculation and fluid-solid interaction. In the CFD-DEM model, the particles are modeled as a discrete phase, following the DEM approach, whereas the fluid flow is treated as a continuous phase, described by the averaged Navier-Stokes equations on a computational cell scale. In this work, the coupling methodology between Fluent and Rocky is described. The numerical approach was applied to the simulation of a bubbling fluidized bed and the results were compared to experimental data and showed good agreement. (author)

  8. Herschel observations of the Centaurus cluster - the dynamics of cold gas in a cool core

    CERN Document Server

    Mittal, Rupal; Ferland, Gary; Oonk, Raymond; Edge, Alastair C; Canning, Rebecca E A; Russell, Helen; Baum, Stefi A; Böhringer, Hans; Combes, Francoise; Donahue, Megan; Fabian, Andy C; Hatch, Nina A; Hoffer, Aaron; Johnstone, Roderick; McNamara, Brian R; Salomé, Philippe; Tremblay, Grant

    2011-01-01

    Brightest cluster galaxies (BCGs) in the cores of galaxy clusters have distinctly different properties from other low redshift massive ellipticals. The majority of the BCGs in cool-core clusters show signs of active star formation. We present observations of NGC 4696, the BCG of the Centaurus galaxy cluster, at far-infrared (FIR) wavelengths with the Herschel space telescope. Using the PACS spectrometer, we detect the two strongest coolants of the interstellar medium, CII at 157.74 micron and OI at 63.18 micron, and in addition NII at 121.90 micron. The CII emission is extended over a region of 7 kpc with a similar spatial morphology and kinematics to the optical H-alpha emission. This has the profound implication that the optical hydrogen recombination line, H-alpha, the optical forbidden lines, NII 6583 Angstrom, the soft X-ray filaments and the far-infrared CII line all have the same energy source. We also detect dust emission using the PACS and SPIRE photometers at all six wavebands. We perform a detailed...

  9. Regional variations in the dense gas heating and cooling in M51 from Herschel far-infrared spectroscopy

    CERN Document Server

    Parkin, T J; Schirm, M R P; Baes, M; Boquien, M; Boselli, A; Cooray, A; Cormier, D; Foyle, K; Karczewski, O L; Lebouteiller, V; de Looze, I; Madden, S C; Roussel, H; Sauvage, M; Spinoglio, L

    2013-01-01

    We present Herschel PACS and SPIRE spectroscopy of the most important far-infrared cooling lines in M51, [CII](158 \\mu m), [NII](122 & 205 \\mu m), [OI](63 and 145 \\mu m) and [OIII](88 \\mu m). We compare the observed flux of these lines with the predicted flux from a photon dominated region model to determine characteristics of the cold gas such as density, temperature and the far-ultraviolet radiation field, G_0, resolving details on physical scales of roughly 600 pc. We find an average [CII]/F_TIR of 4 x 10^{-3}, in agreement with previous studies of other galaxies. A pixel-by-pixel analysis of four distinct regions of M51 shows a radially decreasing trend in both the far-ultraviolet (FUV) radiation field, G_0 and the hydrogen density, n, peaking in the nucleus of the galaxy, then falling off out to the arm and interarm regions. We see for the first time that the FUV flux and gas density are similar in the differing environments of the arm and interarm regions, suggesting that the inherent physical prope...

  10. Tritium permeation behavior through pyrolytic carbon in tritium production using high-temperature gas-cooled reactor for fusion reactors

    Directory of Open Access Journals (Sweden)

    H. Ushida

    2016-12-01

    Full Text Available Under tritium production method using a high-temperature gas-cooled reactor loaded Li compound, Li compound has to be coated by ceramic materials in order to suppress the spreading of tritium to the whole reactor. Pyrolytic carbon (PyC is a candidate of the coating material because of its high resistance for gas permeation. In this study, hydrogen permeation experiments using a PyC-coated isotropic graphite tube were conducted and hydrogen diffusivity, solubility and permeability were evaluated. Tritium permeation behavior through PyC-coated Li compound particles was simulated by using obtained data. Hydrogen permeation flux through PyC in a steady state is proportional to the hydrogen pressure and is larger than that through Al2O3 which is also candidate coating material. However, total tritium leak within the supposed reactor operation period through the PyC-coated Li compound particles is lower than that through the Al2O3-coated ones because the hydrogen absorption capacity in PyC is considerably larger than that in Al2O3.

  11. A feasibility and optimization study to determine cooling time and burnup of advanced test reactor fuels using a nondestructive technique

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Jorge [Univ. of Utah, Salt Lake City, UT (United States)

    2013-12-01

    The goal of this study presented is to determine the best available non-destructive technique necessary to collect validation data as well as to determine burn-up and cooling time of the fuel elements onsite at the Advanced Test Reactor (ATR) canal. This study makes a recommendation of the viability of implementing a permanent fuel scanning system at the ATR canal and leads3 to the full design of a permanent fuel scan system. The study consisted at first in determining if it was possible and which equipment was necessary to collect useful spectra from ATR fuel elements at the canal adjacent to the reactor. Once it was establish that useful spectra can be obtained at the ATR canal the next step was to determine which detector and which configuration was better suited to predict burnup and cooling time of fuel elements non-destructively. Three different detectors of High Purity Germanium (HPGe), Lanthanum Bromide (LaBr3), and High Pressure Xenon (HPXe) in two system configurations of above and below the water pool were used during the study. The data collected and analyzed was used to create burnup and cooling time calibration prediction curves for ATR fuel. The next stage of the study was to determine which of the three detectors tested was better suited for the permanent system. From spectra taken and the calibration curves obtained, it was determined that although the HPGe detector yielded better results, a detector that could better withstand the harsh environment of the ATR canal was needed. The in-situ nature of the measurements required a rugged fuel scanning system, low in maintenance and easy to control system. Based on the ATR canal feasibility measurements and calibration results it was determined that the LaBr3 detector was the best alternative for canal in-situ measurements; however in order to enhance the quality of the spectra collected using this scintillator a deconvolution method was developed. Following the development of the deconvolution method

  12. Evanescent-wave trapping and evaporative cooling of an atomic gas near two-dimensionality

    CERN Document Server

    Hammes, M; Engeser, B; Nägerl, H C; Grimm, R

    2003-01-01

    A dense gas of cesium atoms at the crossover to two-dimensionality is prepared in a highly anisotropic surface trap that is realized with two evanescent light waves. Temperatures as low as 100nK are reached with 20.000 atoms at a phase-space density close to 0.1. The lowest quantum state in the tightly confined direction is populated by more than 60%. The system offers intriguing prospects for future experiments on degenerate quantum gases in two dimensions.

  13. Gas turbine ceramic-coated-vane concept with convection-cooled porous metal core

    Science.gov (United States)

    Kascak, A. F.; Liebert, C. H.; Handschuh, R. F.; Ludwig, L. P.

    1981-01-01

    Analysis and flow experiments on a ceramic-coated-porous-metal vane concept indicated the feasibility, from a heat transfer standpoint, of operating in a high-temperature (2500 F) gas turbine cascade facility. The heat transfer and pressure drop calculations provided a basis for selecting the ceramic layer thickness (to 0.08 in.), which was found to be the dominant factor in the overall heat transfer coefficient. Also an approximate analysis of the heat transfer in the vane trailing edge revealed that with trailing-edge ejection the ceramic thickness could be reduced to (0.01 in.) in this portion of the vane.

  14. A Design on Filter and Cooling for New Gas Generator%一种新型气体发生器的过滤冷却设计

    Institute of Scientific and Technical Information of China (English)

    陈雨; 杨正才; 仵和平; 杨旗; 蔺美君; 何锋彦

    2013-01-01

      为降低气体发生器燃气温度,提高气体清洁度,设计了一种迷宫式过滤冷却机构,相比传统过滤冷却方式,新设计的气体流通路径增加了280%,气体与吸热片接触面积增加了200%。验证试验结果表明迷宫式过滤冷却机构大大提高了气体的清洁度和降温效果。%  Aimed at low temperature and high purity of gas for gas generator, a kind of labyrinth filter and cooling design of gas generator was proposed. Compared to the traditional way, the gas channel length of new design was increased 280%, and the contact area of gas and heat absorption pieces was increased 200%. The verificated test indicated the labyrinth filter and cooling design improves the purity and cooling effect of gas greatly.

  15. Production of liquid fuels with a high-temperature gas-cooled reactor

    Science.gov (United States)

    Quade, R. N.; Vrable, D. L.; Green, L., Jr.

    An exploration is made of the technical, economic and environmental impact feasibility of integrating coal liquefaction methods directly and indirectly with a nuclear reactor source of process heat, with stress on the production of synthetic jet fuel. Production figures and operating costs are compared for indirect conventional and nuclear processes using Lurgi-Fischer-Tropsch technology with direct conventional and nuclear techniques employing the advanced SRC-II technology, and it is concluded that significant advantages in coal savings and environmental impact can be expected from nuclear reactor integration.

  16. Gas-Microjet Reactive Scattering: Collisions of HCl and DCl with Cool Salty Water.

    Science.gov (United States)

    Faust, Jennifer A; Sobyra, Thomas B; Nathanson, Gilbert M

    2016-02-18

    Liquid microjets provide a powerful means to investigate reactions of gases with salty water in vacuum while minimizing gas-vapor collisions. We use this technique to explore the fate of gaseous HCl and DCl molecules impinging on 8 molal LiCl and LiBr solutions at 238 K. The experiments reveal that HCl or DCl evaporate infrequently if they become thermally accommodated at the surface of either solution. In particular, we observe minimal thermal desorption of HCl following HCl collisions and no distinct evidence for rapid, interfacial DCl→HCl exchange following DCl collisions. These results imply that surface thermal motions are not generally strong enough to propel momentarily trapped HCl or DCl back into the gas phase before they ionize and disappear into solution. Instead, only HCl and DCl molecules that scatter directly from the surface escape entry. These recoiling molecules transfer less energy upon collision to LiBr/H2O than to LiCl/H2O, reflecting the heavier mass of Br(-) than of Cl(-) in the interfacial region.

  17. Gas-cooled reactor commercialization study: introduction scenario and commercialization analyses for process heat applications. Final report, July 8, 1977--November 30, 1977

    Energy Technology Data Exchange (ETDEWEB)

    1977-12-01

    This report identifies and presents an introduction scenario which can lead to the operation of High Temperature Gas Cooled Reactor demonstration plants for combined process heat and electric power generation applications, and presents a commercialization analysis relevant to the organizational and management plans which could implement a development program.

  18. Assessment of Silicon Carbide Composites for Advanced Salt-Cooled Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Katoh, Yutai [ORNL; Wilson, Dane F [ORNL; Forsberg, Charles W [ORNL

    2007-09-01

    The Advanced High-Temperature Reactor (AHTR) is a new reactor concept that uses a liquid fluoride salt coolant and a solid high-temperature fuel. Several alternative fuel types are being considered for this reactor. One set of fuel options is the use of pin-type fuel assemblies with silicon carbide (SiC) cladding. This report provides (1) an initial viability assessment of using SiC as fuel cladding and other in-core components of the AHTR, (2) the current status of SiC technology, and (3) recommendations on the path forward. Based on the analysis of requirements, continuous SiC fiber-reinforced, chemically vapor-infiltrated SiC matrix (CVI SiC/SiC) composites are recommended as the primary option for further study on AHTR fuel cladding among various industrially available forms of SiC. Critical feasibility issues for the SiC-based AHTR fuel cladding are identified to be (1) corrosion of SiC in the candidate liquid salts, (2) high dose neutron radiation effects, (3) static fatigue failure of SiC/SiC, (4) long-term radiation effects including irradiation creep and radiation-enhanced static fatigue, and (5) fabrication technology of hermetic wall and sealing end caps. Considering the results of the issues analysis and the prospects of ongoing SiC research and development in other nuclear programs, recommendations on the path forward is provided in the order or priority as: (1) thermodynamic analysis and experimental examination of SiC corrosion in the candidate liquid salts, (2) assessment of long-term mechanical integrity issues using prototypical component sections, and (3) assessment of high dose radiation effects relevant to the anticipated operating condition.

  19. High Pressure Gas Filled RF Cavity Beam Test at the Fermilab MuCool Test Area

    Energy Technology Data Exchange (ETDEWEB)

    Freemire, Ben [Illinois Inst. of Technology, Chicago, IL (United States)

    2013-05-01

    The high energy physics community is continually looking to push the limits with respect to the energy and luminosity of particle accelerators. In the realm of leptons, only electron colliders have been built to date. Compared to hadrons, electrons lose a large amount of energy when accelerated in a ring through synchrotron radiation. A solution to this problem is to build long, straight accelerators for electrons, which has been done with great success. With a new generation of lepton colliders being conceived, building longer, more powerful accelerators is not the most enticing option. Muons have been proposed as an alternative particle to electrons. Muons lose less energy to synchrotron radiation and a Muon Collider can provide luminosity within a much smaller energy range than a comparable electron collider. This allows a circular collider to be built with higher attainable energy than any present electron collider. As part of the accelerator, but separate from the collider, it would also be possible to allow the muons to decay to study neutrinos. The possibility of a high energy, high luminosity muon collider and an abundant, precise source of neutrinos is an attractive one. The technological challenges of building a muon accelerator are many and diverse. Because the muon is an unstable particle, a muon beam must be cooled and accelerated to the desired energy within a short amount of time. This requirement places strict requisites on the type of acceleration and focusing that can be used. Muons are generated as tertiary beams with a huge phase space, so strong magnetic fields are required to capture and focus them. Radio frequency (RF) cavities are needed to capture, bunch and accelerate the muons. Unfortunately, traditional vacuum RF cavities have been shown to break down in the magnetic fields necessary for capture and focusing.

  20. Strandby Harbour on solar cooling. Demonstration of 8.000 m{sup 2} solar collectors combined with flue gas cooling with a absorption cooling system; Combined heat and power plant (CHP); Strandby havn paa solkoeling. Demonstration af 8.000 m{sup 2} solfangere kombineret med roeggaskoeling med absorptionskoeleanlaeg

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Flemming (Strandby Varmevaerk, Strandby (Denmark)); Soerensen, Per Alex (PlanEnergi, Skoerping (Denmark)); Ulbjerg, F. (Ramboell, Odense (Denmark)); Sloth, H. (Houe and Olsen, Thisted (Denmark))

    2010-04-15

    The aim of the project was to demonstrate 1) high solar heating ratio (18% annually) at a decentralized natural gas combined heat and power plant; 2) increased efficiency (5% of the heat consumption) in a natural gas CHP by using an extra flue gas cooler and an absorption heat pump; 3) a double tank system where a new tank during winter is used for cooling/ heat storage for the absorption heat pump and during summer for solar heat storage in serial operation with the old tank. The concept of combining solar power, absorption cooling and natural gas-fired small-scale CHP in Strandby met expectations and could be replicated in other CHP plants. However, it is important to note that if major construction modifications in the flue gas condensation system in the boiler or engine are required, the operating hours must not be reduced significantly in the amortisation period for the conversion. (ln)

  1. Peltier cooled PbSe double-heterostructure lasers for IR-gas spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Preier, H.; Bleicher, M.; Riedel, W.; Pfeiffer, H.; Maier, H. (Allgemeine Elektricitaets-Gesellschaft AEG Telefunken, Frankfurt am Main (Germany, F.R.). Forschungsinstitut)

    1977-01-01

    PbS-PbSe-PbS double-heterostructure lasers have been pulse-operated at about 200 K mounted on 4 stage thermoelectric coolers. Emitting at a wavelength of about 5.5 ..mu..m they could be used for NO gas spectroscopy. Operation temperatures of up to 230 K have been achieved with structures consisting of n-type PbS substrates and epitaxial layers of n-type PbSe and Tl doped p-type PbS. The temperature dependence of the threshold current density and the emission wavelength of these DH-lasers was compared with PbSe-homojunction lasers. The use of a germanium etalon for a quick evaluation of the spectral quality of the emitted radiation is described.

  2. Gas-Cooled Thermal Reactor Program. Semiannual technical progress report, April 1, 1983-September 30, 1983

    Energy Technology Data Exchange (ETDEWEB)

    1983-12-01

    An assessment of the HTGR opportunities from the year 2000 through 2045 was the principal activity on the Market Definition Task (WBS 03). Within the Plant Technology (WBS 13) task, there were activities to develop analytical methods for investigation of Coolant Transport Behavior and to define methods and criteria for High Temperature Structural Engineering design. The activities in support of the HTGR-SC/C Lead Plant (WBS 30 and 31) were the participation in the Lead Plant System Engineering (LPSE) effort and the plant simulation task. The efforts on the Advanced HTGR systems was performed under the Modular Reactor Systems (MRS) (WBS 41) to study the potential for multiple small reactors to provide lower costs, improved safety, and higher availability than the large monolithic core reactors.

  3. Life prediction of advanced materials for gas turbine application

    Energy Technology Data Exchange (ETDEWEB)

    Zamrik, S.Y.; Ray, A.; Koss, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-10-01

    Most of the studies on the low cycle fatigue life prediction have been reported under isothermal conditions where the deformation of the material is strain dependent. In the development of gas turbines, components such as blades and vanes are exposed to temperature variations in addition to strain cycling. As a result, the deformation process becomes temperature and strain dependent. Therefore, the life of the component becomes sensitive to temperature-strain cycling which produces a process known as {open_quotes}thermomechanical fatigue, or TMF{close_quotes}. The TMF fatigue failure phenomenon has been modeled using conventional fatigue life prediction methods, which are not sufficiently accurate to quantitatively establish an allowable design procedure. To add to the complexity of TMF life prediction, blade and vane substrates are normally coated with aluminide, overlay or thermal barrier type coatings (TBC) where the durability of the component is dominated by the coating/substrate constitutive response and by the fatigue behavior of the coating. A number of issues arise from TMF depending on the type of temperature/strain phase cycle: (1) time-dependent inelastic behavior can significantly affect the stress response. For example, creep relaxation during a tensile or compressive loading at elevated temperatures leads to a progressive increase in the mean stress level under cyclic loading. (2) the mismatch in elastic and thermal expansion properties between the coating and the substrate can lead to significant deviations in the coating stress levels due to changes in the elastic modulii. (3) the {open_quotes}dry{close_quotes} corrosion resistance coatings applied to the substrate may act as primary crack initiation sites. Crack initiation in the coating is a function of the coating composition, its mechanical properties, creep relaxation behavior, thermal strain range and the strain/temperature phase relationship.

  4. New dual gas puff imaging system with up-down symmetry on experimental advanced superconducting tokamak

    DEFF Research Database (Denmark)

    Liu, S. C.; Shao, L. M.; Zweben, S. J.;

    2012-01-01

    advanced superconducting tokamak (EAST). The two views are up-down symmetric about the midplane and separated by a toroidal angle of 66.6 degrees. A linear manifold with 16 holes apart by 10 mm is used to form helium gas cloud at the 130x130 mm (radial versus poloidal) objective plane. A fast camera...

  5. Advanced gas turbine systems research. Quarterly report, October--December 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    This report summarizes the major accomplishments and reports issued by Advanced Gas Turbine Systems Research (AGTSR) during October 1, 1995 to December 31, 1995, reports on changes in the AGTSR membership, describes 1993, 1994 and 1995 subcontract progress, third combustion workshop, first combustion specialty meeting, materials workshop, industrial internship, research topics highlighted, and seminar sponsorship.

  6. Novel concepts and geometries as alternatives to conventional circular pin fins for gas turbine blade cooling applications

    Science.gov (United States)

    Uzol, Oguz

    momentum wake region compared to the wakes of the elliptical fins. Hence, the SEFs and the N fins are found to be excellent alternatives to conventional circular pin fins used in gas turbine blade cooling applications.

  7. Direct frequency comb laser cooling and trapping

    CERN Document Server

    Jayich, A M; Campbell, W C

    2016-01-01

    Continuous wave (CW) lasers are the enabling technology for producing ultracold atoms and molecules through laser cooling and trapping. The resulting pristine samples of slow moving particles are the de facto starting point for both fundamental and applied science when a highly-controlled quantum system is required. Laser cooled atoms have recently led to major advances in quantum information, the search to understand dark energy, quantum chemistry, and quantum sensors. However, CW laser technology currently limits laser cooling and trapping to special types of elements that do not include highly abundant and chemically relevant atoms such as hydrogen, carbon, oxygen, and nitrogen. Here, we demonstrate that Doppler cooling and trapping by optical frequency combs may provide a route to trapped, ultracold atoms whose spectra are not amenable to CW lasers. We laser cool a gas of atoms by driving a two-photon transition with an optical frequency comb, an efficient process to which every comb tooth coherently cont...

  8. Design of a rapidly cooled cryogenic mirror

    Science.gov (United States)

    Plummer, Ron; Hsu, Ike

    1993-01-01

    The paper discusses the design, analysis, and testing of a rapidly cooled beryllium cryogenic mirror, which is the primary mirror in the four-element optical system for the Long Wavelength Infrared Advanced Technology Seeker. The mirror is shown to meet the requirement of five minutes for cooling to cryogenic operating temperature; it also maintains its optical figure and vacuum integrity and meets the nuclear specification. Results of a detailed thermal analysis on the mirror showed that, using nitrogen gas at 80 K as coolant, the front face of the mirror can be cooled from an initial temperature of 300 K to less than 90 K within five minutes. In a vacuum chamber, using liquid nitrogen as coolant, the mirror can be cooled to 80 K within 1.5 min. The mirror is well thermally insulated, so that it can be maintained at less than its operating temperature for a long time without active cooling.

  9. Analyses of the reflector tank, cold source, and beam tube cooling for ANS reactor. [Advanced Neutron Source (ANS)

    Energy Technology Data Exchange (ETDEWEB)

    Marland, S. (Tennessee Univ., Knoxville, TN (United States))

    1992-07-01

    This report describes my work as an intern with Martin Marietta Energy Systems, Inc., in the summer of 1991. I was assigned to the Reactor Technology Engineering Department, working on the Advanced Neutron Source (ANS). My first project was to select and analyze sealing systems for the top of the diverter/reflector tank. This involved investigating various metal seals and calculating the forces necessary to maintain an adequate seal. The force calculations led to an analysis of several bolt patterns and lockring concepts that could be used to maintain a seal on the vessel. Another project involved some pressure vessel stress calculations and the calculation of the center of gravity for the cold source assembly. I also completed some sketches of possible cooling channel patterns for the inner vessel of the cold source. In addition, I worked on some thermal design analyses for the reflector tank and beam tubes, including heat transfer calculations and assisting in Patran and Pthermal analyses. To supplement the ANS work, I worked on other projects. I completed some stress/deflection analyses on several different beams. These analyses were done with the aid of CAASE, a beam-analysis software package. An additional project involved bending analysis on a carbon removal system. This study was done to find the deflection of a complex-shaped beam when loaded with a full waste can.

  10. Advanced combustion technologies for gas turbine power plants

    Energy Technology Data Exchange (ETDEWEB)

    Vandsburger, U.; Desu, S.B. [Virginia Tech, Blacksburg, VA (United States); Roe, L.A.

    1995-10-01

    During the second half of fiscal year 1995 progress was made in all three funded subject areas of the project as well as in a new area. Work in the area of mixing and combustion management through flow actuation was transferred into an enclosed facility. Jet mixing in a ducted co-flow was examined. The same jets were also subjected to a strong acoustic field established in the duct. Excitation of the jet with static spatial modes was shown to be effective even in the presence of co-flow and the acoustic field. Only when a wall is placed at the jet exit plane did the acoustic field dominate the jet dispersion (as expected due to reflective boundary conditions and the jet shear layer receptivity). This case is, however, not the most relevant to gas turbine combustors since it precludes co-flow. In the area of combustor testing, the design, fabrication, and assembly of a modular combustor test rig for project has been completed at the University of Arkansas. In the area of high temperature piezoceramic actuator materials development, Sr{sub 2}(Nb{sub x}Ta{sub 1-x}){sub 2}O{sub 7} powders have been synthesized, and bulk samples and thick films sintered. These materials have a curie temperature of about 1400{degrees}C compared with 300{degrees}C for the commercially available PZT. While at room temperature the new materials show a piezoelectric constant (d{sub 33}) which is a factor of 100 lower than PZT, at high temperatures they can exhibit significant action. A new area of non-linear, neural-net based, controllers for mixing and combustion control has been added during the second contract year. This work is not funded by the contract. Significant progress was made in this area. Neural nets with up to 15 neurons in the hidden layer were trained with experimental data and also with data generated using linear stability theory. System ID was performed successfully. The network was then used to predict the behavior of jets excited at other modes not used for the training.

  11. Evidence of refilled chamber gas pressure enhancing cooling rate during melt spinning of a Zr50Cu40Al10 alloy

    Institute of Scientific and Technical Information of China (English)

    Hong-wang Yang; Peng Zhang; M J Tan; Yuan Ge; Wan-ping Tian; Rui-chun Wang; Rong-de Li

    2015-01-01

    The inlfuence of the reifl ed gas pressure on the glass forming behaviour of one of the best ternary glass forming al oys Zr50Cu40Al10 was studied for the melt spinning process. The amorphicity of as-quenched ribbons was characterized by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The reifl ed chamber atmospheric pressure is crucial to the cooling rate of melt spinning. At high vacuum, at pressure less than 0.0001 atm, ful y crystal ine fragments are obtained. Monolithic amorphous ribbons were only obtained at a gas pressure of 0.1 atm or higher. The extended contact length between thecribbons and the copper wheel contributes to the high cooling rate of melt spinning. Higher chamber gas pressure leads to more turbulence of liquid metal beneath the nozzle;therefore, lower pressure is preferable at practical melt spinning processes once glass forming conditions are fulifl ed.

  12. Scaling Studies for High Temperature Test Facility and Modular High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Richard R. Schult; Paul D. Bayless; Richard W. Johnson; James R. Wolf; Brian Woods

    2012-02-01

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5-year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant (NGNP) project. Because the NRC's interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC).

  13. High Temperature Gas-Cooled Reactors Lessons Learned Applicable to the Next Generation Nuclear Plant

    Energy Technology Data Exchange (ETDEWEB)

    J. M. Beck; L. F. Pincock

    2011-04-01

    The purpose of this report is to identify possible issues highlighted by these lessons learned that could apply to the NGNP in reducing technical risks commensurate with the current phase of design. Some of the lessons learned have been applied to the NGNP and documented in the Preconceptual Design Report. These are addressed in the background section of this document and include, for example, the decision to use TRISO fuel rather than BISO fuel used in the Peach Bottom reactor; the use of a reactor pressure vessel rather than prestressed concrete found in Fort St. Vrain; and the use of helium as a primary coolant rather than CO2. Other lessons learned, 68 in total, are documented in Sections 2 through 6 and will be applied, as appropriate, in advancing phases of design. The lessons learned are derived from both negative and positive outcomes from prior HTGR experiences. Lessons learned are grouped according to the plant, areas, systems, subsystems, and components defined in the NGNP Preconceptual Design Report, and subsequent NGNP project documents.

  14. The Cool ISM in Elliptical Galaxies. II. Gas Content in the Volume - Limited Sample and Results from the Combined Elliptical and Lenticular Surveys

    CERN Document Server

    Welch, Gary A; Young, Lisa M

    2010-01-01

    We report new observations of atomic and molecular gas in a volume limited sample of elliptical galaxies. Combining the elliptical sample with an earlier and similar lenticular one, we show that cool gas detection rates are very similar among low luminosity E and SO galaxies but are much higher among luminous S0s. Using the combined sample we revisit the correlation between cool gas mass and blue luminosity which emerged from our lenticular survey, finding strong support for previous claims that the molecular gas in ellipticals and lenticulars has different origins. Unexpectedly, however, and contrary to earlier claims, the same is not true for atomic gas. We speculate that both the AGN feedback and merger paradigms might offer explanations for differences in detection rates, and might also point towards an understanding of why the two gas phases could follow different evolutionary paths in Es and S0s. Finally we present a new and puzzling discovery concerning the global mix of atomic and molecular gas in ear...

  15. FABRICATE AND TEST AN ADVANCED NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Eugene Baxter; Roger E. Anderson; Stephen E. Doyle

    2003-06-01

    In September 2000 the Department of Energy's National Energy Technology Laboratory (DOE/NETL) contracted with Clean Energy Systems, Inc. (CES) of Sacramento, California to design, fabricate, and test a 20 MW{sub t} (10 MW{sub e}) gas generator. Program goals were to demonstrate a non-polluting gas generator at temperatures up to 3000 F at 1500 psi, and to demonstrate resulting drive gas composition, comprising steam and carbon dioxide substantially free of pollutants. Following hardware design and fabrication, testing, originally planned to begin in the summer of 2001, was delayed by unavailability of the contracted test facility. CES designed, fabricated, and tested the proposed gas generator as originally agreed. The CES process for producing near-zero-emissions power from fossil fuels is based on the near-stoichiometric combustion of a clean gaseous fuel with oxygen in the presence of recycled water, to produce a high-temperature, high-pressure turbine drive fluid comprising steam and carbon dioxide. Tests demonstrated igniter operation over the prescribed ranges of pressure and mixture ratios. Ignition was repeatable and reliable through more than 100 ignitions. Injector design ''A'' was operated successfully at both low power ({approx}20% of rated power) and at rated power ({approx}20 MW{sub t}) in more than 95 tests. The uncooled gas generator configuration (no diluent injectors or cooldown chambers installed) produced drive gases at temperatures approaching 3000 F and at pressures greater than 1550 psia. The fully cooled gas generator configuration, with cooldown chambers and injector ''A'', operated consistently at pressures from 1100 to 1540 psia and produced high pressure, steam-rich turbine drive gases at temperatures ranging from {approx}3000 to as low as 600 F. This report includes description of the intended next steps in the gas generator technology demonstration and traces the anticipated pathway to

  16. Mandate a Man to Fish?: Technological advance in cooling systems at U.S. thermal electric plants

    Science.gov (United States)

    Peredo-Alvarez, Victor M.; Bellas, Allen S.; Trainor-Guitton, Whitney J.; Lange, Ian

    2016-02-01

    Steam-based electrical generating plants use large quantities of water for cooling. The potential environmental impacts of water cooling systems have resulted in their inclusion in the Clean Water Act's (CWA) Sections 316(a), related to thermal discharges and 316(b), related to cooling water intake. The CWA mandates a technological standard for water cooling systems. This analysis examines how the performance-adjusted rates of thermal emissions and water withdrawals for cooling units have changed over their vintage and how these rates of change were impacted by imposition of the CWA. Results show that the rate of progress increased for cooling systems installed after the CWA whilethere was no progress previous to it.

  17. Reliability Assessment of 2400 MWth Gas-Cooled Fast Reactor Natural Circulation Decay Heat Removal in Pressurized Situations

    Directory of Open Access Journals (Sweden)

    C. Bassi

    2008-01-01

    Full Text Available As the 2400 MWth gas-cooled fast reactor concept makes use of passive safety features in combination with active safety systems, the question of natural circulation decay heat removal (NCDHR reliability and performance assessment into the ongoing probabilistic safety assessment in support to the reactor design, named “probabilistic engineering assessment” (PEA, constitutes a challenge. Within the 5th Framework Program for Research and Development (FPRD of the European Community, a methodology has been developed to evaluate the reliability of passive systems characterized by a moving fluid and whose operation is based on physical principles, such as the natural circulation. This reliability method for passive systems (RMPSs is based on uncertainties propagation into thermal-hydraulic (T-H calculations. The aim of this exercise is finally to determine the performance reliability of the DHR system operating in a “passive” mode, taking into account the uncertainties of parameters retained for thermal-hydraulical calculations performed with the CATHARE 2 code. According to the PEA preliminary results, exhibiting the weight of pressurized scenarios (i.e., with intact primary circuit boundary for the core damage frequency (CDF, the RMPS exercise is first focusing on the NCDHR performance at these T-H conditions.

  18. [USA/FRG cooperation in gas-cooled reactor development]. Foreign trip report, June 24--July 2, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Jones, Jr, J E

    1988-07-26

    Reviews were conducted at Kernforschungsanlage (KFA) Juelich of the US and Federal Republic of Germany (FRG) high-temperature gas-cooled reactor (HTGR) programs under the US/FRG Umbrella Agreement, with emphasis on those technology development areas where cooperation is ongoing and planned. Specific subprogram areas are safety; materials; fuels, fission products, and graphite; and Arbeitsgemeinschaft Versuchs-Reaktor (AVR). The purpose was to assess the status of the cooperation, reach agreement on any changes needed, and identify new areas of cooperation. Overall, the agreement has been both effective and beneficial. Ongoing activities complement and support US technology development plans. Discussions were held in the United Kingdom (UK) at the Risley Nuclear Power Development Laboratory regarding a potential graphite technology exchange program between the US Department of Energy and the UK Atomic Energy Authority. A draft agreement was reviewed and appeared to be satisfactory to both parties and ready for signature. A summary of potential areas of activity in the exchange had been prepared by US representatives and was discussed and found to be acceptable to UK representatives.

  19. Efficient transfer of positrons from a buffer-gas-cooled accumulator into an orthogonally oriented superconducting solenoid for antihydrogen studies

    CERN Document Server

    Comeau, D; Fitzakerley, D; George, M C; Hessels, E A; Storry, C H; Weel, M; Grzonka, D; Oelert, W; Gabrielse, G; Kalra, R; Kolthammer, W S; McConnell, R; Richerme, P; Mullers, A; Walz, J

    2012-01-01

    Positrons accumulated in a room-temperature buffer-gas-cooled positron accumulator are efficiently transferred into a superconducting solenoid which houses the ATRAP cryogenic Penning trap used in antihydrogen research. The positrons are guided along a 9 m long magnetic guide that connects the central field lines of the 0.15 T field in the positron accumulator to the central magnetic field lines of the superconducting solenoid. Seventy independently controllable electromagnets are required to overcome the fringing field of the large-bore superconducting solenoid. The guide includes both a 15 degrees upward bend and a 105 degrees downward bend to account for the orthogonal orientation of the positron accumulator with respect to the cryogenic Penning trap. Low-energy positrons ejected from the accumulator follow the magnetic field lines within the guide and are transferred into the superconducting solenoid with nearly 100% efficiency. A 7 m long 5 cm diameter stainless-steel tube and a 20 mm long, 1.5 mm diamet...

  20. Gas-cooled reactor programs. Fuel-management positioning and accounting module: FUELMANG Version V1. 11, September 1981

    Energy Technology Data Exchange (ETDEWEB)

    Medlin, T.W.; Hill, K.L.; Johnson, G.L.; Jones, J.E.; Vondy, D.R.

    1982-01-01

    This report documents the code module FUELMANG for fuel management of a reactor. This code may be used to position fuel during the calculation of a reactor history, maintain a mass balance history of the fuel movement, and calculate the unit fuel cycle component of the electrical generation cost. In addition to handling fixed feed fuel without recycle, provision has been made for fuel recycle with various options applied to the recycled fuel. A continuous fueling option is also available with the code. A major edit produced by the code is a detailed summary of the mass balance history of the reactor and a fuel cost analysis of that mass balance history. This code is incorporated in the system containing the VENTURE diffusion theory neutronics code for routine use. Fuel movement according to prescribed instructions is performed without the access of additional user input data during the calculation of a reactor operating history. Local application has been primarily for analysis of the performance of gas-cooled thermal reactor core concepts.

  1. Detection of hidden shot balls in a gas-cooled turbine blade with an NRT gadolinium tagging method

    Science.gov (United States)

    Sim, Cheul Muu; Kim, Yi Kyung; Kim, TaeJoo; Lee, Kye Hong; Kim, Jeong Uk

    2009-06-01

    This report provides a preliminary insight into the benefits and effectiveness of neutron radiography in identifying alien materials, namely shot balls hidden in a turbine blade that are otherwise undetected using other methods. The detection of 0.2-mm-diameter shot balls in gas-cooled turbine blades is possible for thermal neutron radiography. A tagging processing is more useful for a distinctive image of newer turbine blades. Areas of concern for the tagging process include the solution concentration and the possibility of a slight washing of the blades. The location of the shot balls within the turbine blades tagged with Gd((2%, 5%)+water) was shown. Shot balls were placed externally on a turbine blade (F100-700, F100-200) surface in order to check for a dead zone from a surface examination. The image is produced from neutron radiography after a 5 min exposure time. When the blade is tagged with 2% and 5% Gd with slight washing, the shot can also be effectively seen on the SR-45 film. Shot balls are more obvious on a neutron image SR-45 film than an image plate or a DR film.

  2. Analysis of Fluid Flow and Heat Transfer Model for the Pebble Bed High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    S. Yamoah

    2012-06-01

    Full Text Available The pebble bed type high temperature gas cooled nuclear reactor is a promising option for next generation reactor technology and has the potential to provide high efficiency and cost effective electricity generation. The reactor unit heat transfer poses a challenge due to the complexity associated with the thermalflow design. Therefore to reliably simulate the flow and heat transport of the pebble bed modular reactor necessitates a heat transfer model that deals with radiation as well as thermal convection and conduction. In this study, a model with the capability to simulate fluid flow and heat transfer in the pebble bed modular reactor core has been developed. The developed model was implemented on a personal computer using FORTRAN 95 programming language. Several important fluid flow and heat transfer parameters have been examined: including the pressure drop over the reactor core, the heat transfer coefficient, the Nusselt number and the effective thermal conductivity of the fuel pebbles. Results obtained from the simulation experiments show a uniform pressure in the radial direction for a core to fuel element diameter (D/d ratio>20 and the heat transfer coefficient increases with increasing temperature and coolant mass flow rate. The model can adequately account for the flow and heat transfer phenomenon and the loss of pressure through friction in the pebble bed type high temperature nuclear reactor.

  3. An Artificial Neural Network Compensated Output Feedback Power-Level Control for Modular High Temperature Gas-Cooled Reactors

    Directory of Open Access Journals (Sweden)

    Zhe Dong

    2014-02-01

    Full Text Available Small modular reactors (SMRs could be beneficial in providing electricity power safely and also be viable for applications such as seawater desalination and heat production. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR has been seen as one of the best candidates for building SMR-based nuclear power plants. Since the MHTGR dynamics display high nonlinearity and parameter uncertainty, it is necessary to develop a nonlinear adaptive power-level control law which is not only beneficial to the safe, stable, efficient and autonomous operation of the MHTGR, but also easy to implement practically. In this paper, based on the concept of shifted-ectropy and the physically-based control design approach, it is proved theoretically that the simple proportional-differential (PD output-feedback power-level control can provide asymptotic closed-loop stability. Then, based on the strong approximation capability of the multi-layer perceptron (MLP artificial neural network (ANN, a compensator is established to suppress the negative influence caused by system parameter uncertainty. It is also proved that the MLP-compensated PD power-level control law constituted by an experientially-tuned PD regulator and this MLP-based compensator can guarantee bounded closed-loop stability. Numerical simulation results not only verify the theoretical results, but also illustrate the high performance of this MLP-compensated PD power-level controller in suppressing the oscillation of process variables caused by system parameter uncertainty.

  4. Evaluation of radiation heat transfer in porous medial: Application for a pebble bed modular reactor cooled by CO2 gas

    Directory of Open Access Journals (Sweden)

    Sidi-Ali Kamel

    2013-01-01

    Full Text Available This work analyses the contribution of radiation heat transfer in the cooling of a pebble bed modular reactor. The mathematical model, developed for a porous medium, is based on a set of equations applied to an annular geometry. Previous major works dealing with the subject have considered the forced convection mode and often did not take into account the radiation heat transfer. In this work, only free convection and radiation heat transfer are considered. This can occur during the removal of residual heat after shutdown or during an emergency situation. In order to derive the governing equations of radiation heat transfer, a steady-state in an isotropic and emissive porous medium (CO2 is considered. The obtained system of equations is written in a dimensionless form and then solved. In order to evaluate the effect of radiation heat transfer on the total heat removed, an analytical method for solving the system of equations is used. The results allow quantifying both radiation and free convection heat transfer. For the studied situation, they show that, in a pebble bed modular reactor, more than 70% of heat is removed by radiation heat transfer when CO2 is used as the coolant gas.

  5. Output Feedback Dissipation Control for the Power-Level of Modular High-Temperature Gas-Cooled Reactors

    Directory of Open Access Journals (Sweden)

    Zhe Dong

    2011-11-01

    Full Text Available Because of its strong inherent safety features and the high outlet temperature, the modular high temperature gas-cooled nuclear reactor (MHTGR is the chosen technology for a new generation of nuclear power plants. Such power plants are being considered for industrial applications with a wide range of power levels, thus power-level regulation is very important for their efficient and stable operation. Exploiting the large scale asymptotic closed-loop stability provided by nonlinear controllers, a nonlinear power-level regulator is presented in this paper that is based upon both the techniques of feedback dissipation and well-established backstepping. The virtue of this control strategy, i.e., the ability of globally asymptotic stabilization, is that it takes advantage of the inherent zero-state detectability property of the MHTGR dynamics. Moreover, this newly built power-level regulator is also robust towards modeling uncertainty in the control rod dynamics. If modeling uncertainty of the control rod dynamics is small enough to be omitted, then this control law can be simplified to a classical proportional feedback controller. The comparison of the control performance between the newly-built power controller and the simplified controller is also given through numerical study and theoretical analysis.

  6. Model based predictive control of a high temperature gas cooled power plant coupled to a hydrogen production facility

    Science.gov (United States)

    Rhoads, Lloyd A.

    This thesis builds upon recent studies focusing on modeling, operation, and control of high temperature gas cooled reactors. A computer model was developed, based on mass, energy, and momentum balances of control volumes throughout the plant. Several simulations of the plant behavior were conducted and their results were compared with those from the literature. Proportional control was combined with optimal control to form a time varying, adjustable gain predictive controller which adjusts the proportional gains during transients. The controller was designed to utilize control rod motions and bypass control valves to maintain desired plant conditions. An optimization scheme was introduced to efficiently solve the optimization problem formulated as part of the predictive controller operation. Several additional transients were run to examine the full plant controller performance. Multiple predictive controllers were designed and their performance was compared with a proportional controller throughout each transient. The predictive controller results confirmed the importance of proper selection of the optimal controller parameters, in particular the controller time step size and the horizon time. The well-designed proportional controllers clearly demonstrated improvements in plant performance during short time scale transients, namely a loss of secondary heat transfer transient and a step change in desired power transient. Results from long time scale transients demonstrated the capabilities of the proposed bypass control system to control electrical power production without the need for storage vessels.

  7. Observations of asymmetric velocity fields and gas cooling in the NGC 4636 galaxy group X-ray halo

    CERN Document Server

    Ahoranta, Jussi; Pinto, Ciro; Sanders, Jeremy; Kaastra, Jelle; de Plaa, Jelle; Fabian, Andrew

    2016-01-01

    This study aims to probe the thermodynamic properties of the hot intragroup medium (IGM) plasma in the core regions of the NGC 4636 galaxy group by detailed measurements of several emission lines and their relative intensities. We analyzed deep XMM-Newton Reflection Grating Spectrometer (RGS) data in five adjacent spectral regions in the central parts of the NGC 4636 galaxy group. We examined the suppression of the Fe xvii resonance line (15.01 {\\AA}) as compared to the forbidden lines of the same ion (17.05 {\\AA} and 17.10 {\\AA}). The presence and radial dependence of the cooling flow was investigated through spectral modeling. In addition, a parallel analysis with deep Chandra Advances CCD Imaging Spectrometer (ACIS) data was conducted to gain additional information about the thermodynamical properties of the IGM. We find that the plasma at the group center to the north shows efficient Fe xvii ion resonant scattering, wheras no resonant scattering was detected at the south side. The regions featuring resona...

  8. 10MW高温气冷实验堆的堆体结构特点%Features of Reactor Structure Design for 10MW High Temperature Gas-Cooled Reactor

    Institute of Scientific and Technical Information of China (English)

    刘俊杰; 王敏稚; 张征明; 张振声; 何树延

    2001-01-01

    模块式高温气冷堆是当今世界上公认的先进反应堆堆型之一。固有安全性是它的最突出的优点。本文对 10 MW高温气冷堆的堆体布置进行了详细描述,并对 10MW高温气冷堆的结构设计特点进行了分析。根据 10 MW高温气冷堆的特点,本文对该堆的固有安全性、制造工艺等方面的优点进行了论述。%As the world-wide accepted advanced nuclear reactor,the most prominent characteristic of High-temperature Gas-cooled Modular Reactor is its inherent safety.The core arrangement of the 10MW High-temperature Gas-cooled Reactor,which is now under construction,is described in detail.The features of its structure design are analyzed,and based on these features,the advantages of inherent safety and manufacture are also discussed.

  9. Generation IV nuclear energy system initiative. Large GFR core subassemblydesign for the Gas-Cooled Fast Reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E. A.; Kulak, R. F.; Therios, I. U.; Wei, T. Y. C.

    2006-07-31

    Gas-cooled fast reactor (GFR) designs are being developed to meet Gen IV goals of sustainability, economics, safety and reliability, and proliferation resistance and physical protection as part of an International Generation IV Nuclear Energy System Research Initiative effort. Different organizations are involved in the development of a variety of GFR design concepts. The current analysis has focused on the evaluation of low-pressure drop, pin-core designs with favorable passive cooling properties. Initial evaluation of the passive cooling safety case for the GFR during depressurized decay heat removal accidents with concurrent loss of electric power have resulted in requirements for a reduction of core power density to the 100 w/cc level and a low core pressure drop of 0.5 bars. Additional design constraints and the implementation of their constraints are evaluated in this study to enhance and passive cooling properties of the reactor. Passive cooling is made easier by a flat radial distribution of the decay heat. One goal of this study was to evaluate the radial power distribution and determine to what extent it can be flattened, since the decay heat is nearly proportional to the fission power at shutdown. In line with this investigation of the radial power profile, an assessment was also made of the control rod configuration. The layout provided a large number of control rod locations with a fixed area provided for control rods. The number of control rods was consistent with other fast reactor designs. The adequacy of the available control rod locations was evaluated. Future studies will be needed to optimize the control rod designs and evaluate the shutdown system. The case for low pressure drop core can be improved by the minimization of pressure drop sources such as the number of required fuel spacers in the subassembly design and by the details of the fuel pin design. The fuel pin design is determined by a number of neutronic, thermal-hydraulic (gas dynamics

  10. Review: gas-phase ion chemistry of the noble gases: recent advances and future perspectives.

    Science.gov (United States)

    Grandinetti, Felice

    2011-01-01

    This review article surveys recent experimental and theoretical advances in the gas-phase ion chemistry of the noble gases. Covered issues include the interaction of the noble gases with metal and non-metal cations, the conceivable existence of covalent noble-gas anions, the occurrence of ion-molecule reactions involving singly-charged xenon cations, and the occurrence of bond-forming reactions involving doubly-charged cations. Research themes are also highlighted, that are expected to attract further interest in the future.

  11. Study of Change of Refrigerant R22 in Units Cooling through simulation in Ecosimpro; Estudio de Cambio de Gas Refrigerante R22 en Unidades enfriadoras mediante simulacion en Ecosimpro

    Energy Technology Data Exchange (ETDEWEB)

    Prieto Urbano, J.; Molina, M. C.; Gavilan, C.; Olmedo, J.

    2013-07-01

    The project is based on the thermodynamic study of the circuit of cooling of cooling units employing the EcosimPro software, with the objective, through analysis of the theoretical performance of cooling units with different gas cooling, find substitute refrigerant gas more suitable for the analyzed units coolers. This study is being conducted due to the regulations of the EC Regulation No. 2037 / 2000, according to the which, starting from the year 2010, it is prohibited to import, produce, sell, and/or use of R-22 Virgin, while the use of recycled R22 allowed until January 1 of the year 2015.

  12. A simplified Probabilistic Safety Assesment of a Steam-Methane Reforming Hydrogen Production Plant coupled to a High-Temperature Gas Cooled Nuclear Reactor

    OpenAIRE

    Nelson Edelstein, Pamela; Flores Flores, Alain; Francois Lacouture, Juan Luis

    2005-01-01

    A Probabilistic Safety Assessment (PSA) is being developed for a steam-methane reforming hydrogen production plant linked to a High-Temperature Gas Cooled Nuclear Reactor (HTGR). This work is based on the Japan Atomic Energy Research Institute’s (JAERI) High Temperature Test Reactor (HTTR) prototype in Japan. This study has two major objectives: calculate the risk to onsite and offsite individuals, and calculate the frequency of different types of damage to the complex. A simplified HAZOP...

  13. Development of Natural Gas Fired Combined Cycle Plant for Tri-Generation of Power, Cooling and Clean Water Using Waste Heat Recovery: Techno-Economic Analysis

    OpenAIRE

    Gowtham Mohan; Sujata Dahal; Uday Kumar; Andrew Martin; Hamid Kayal

    2014-01-01

    Tri-generation is one of the most efficient ways for maximizing the utilization of available energy. Utilization of waste heat (flue gases) liberated by the Al-Hamra gas turbine power plant is analyzed in this research work for simultaneous production of: (a) electricity by combining steam rankine cycle using heat recovery steam generator (HRSG); (b) clean water by air gap membrane distillation (AGMD) plant; and (c) cooling by single stage vapor absorption chiller (VAC). The flue gases liber...

  14. Apparatus and method for maintaining multi-component sample gas constituents in vapor phase during sample extraction and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Felix, Larry Gordon; Farthing, William Earl; Irvin, James Hodges; Snyder, Todd Robert

    2010-05-11

    A dilution apparatus for diluting a gas sample. The apparatus includes a sample gas conduit having a sample gas inlet end and a diluted sample gas outlet end, and a sample gas flow restricting orifice disposed proximate the sample gas inlet end connected with the sample gas conduit and providing fluid communication between the exterior and the interior of the sample gas conduit. A diluted sample gas conduit is provided within the sample gas conduit having a mixing end with a mixing space inlet opening disposed proximate the sample gas inlet end, thereby forming an annular space between the sample gas conduit and the diluted sample gas conduit. The mixing end of the diluted sample gas conduit is disposed at a distance from the sample gas flow restricting orifice. A dilution gas source connected with the sample gas inlet end of the sample gas conduit is provided for introducing a dilution gas into the annular space, and a filter is provided for filtering the sample gas. The apparatus is particularly suited for diluting heated sample gases containing one or more condensable components.

  15. Theoretical study and design of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane and intended for cooling of gas transported in a gas-main pipeline

    KAUST Repository

    Petrenko, V.O.

    2011-11-01

    This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine compressor, a combined electrogenerating plant and an ejector refrigeration unit operating with a hydrocarbon refrigerant. The combined electrogenerating plant consists of a high-temperature steam-power cycle and a low-temperature hydrocarbon vapor power cycle, which together comprise a binary vapor system. The combined system is designed for the highest possible effectiveness of power generation and could find wide application in gas-transmission systems of gas-main pipelines. Application of the proposed system would enable year-round power generation and provide cooling of natural gas during periods of high ambient temperature operation. This paper presents the main results of a theoretical study and design performance specifications of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane. © 2010 Elsevier Ltd and IIR. All rights reserved.

  16. The impact of the weather conditions on the cooling performance of the heat pump driven by an internal natural gas combustion engine

    Directory of Open Access Journals (Sweden)

    Janovcová Martina

    2015-01-01

    Full Text Available Market with sources of heat and cold offers unlimited choice of different power these devices, design technology, efficiency and price categories. New progressive technologies are constantly discovering, about which is still little information, which include heat pumps powered by a combustion engine running on natural gas. A few pieces of these installations are in Slovakia, but no studies about their work and effectiveness under real conditions. This article deals with experimental measurements of gas heat pump efficiency in cooling mode. Since the gas heat pump works only in system air – water, air is the primary low – energy source, it is necessary to monitor the impact of the climate conditions for the gas heat pump performance.

  17. Effect of advanced injection timing on the performence of natural gas in diesel engines

    Indian Academy of Sciences (India)

    O M I Nwafor

    2000-02-01

    Concern over the environment and/or the increasing demand for conventional fossil fuel has promoted interest in the development of alternative sources of fuel energy for internal combustion (IC) engines. The effect ofadvanced injection timing on the performance of natural gas used as primary fuel in dual-fuel combustion has been examined. Satisfactory diesel engine combustion demands self-ignition of the fuel as it is injected near the top dead centre (TDC) into the hot swirling compressed cylinder gas. Longer delays between injection and ignition lead to unacceptable rates of pressure rise (diesel knock) because too much fuel is ready to burn when combustion eventually occurs. Natural gas has been noted to exhibit longer ignition delays and slower burning rates especially at low load levels hence resulting in late combustion in the expansion stroke. Advanced injection timing is expected to compensate for these effects. The engine has standard injection timing of 30° before TDC (BTDC). The injection was first advanced by 5.5° given injection timing of 35.5° BTDC. The engine ran for about 5 minutes at this timing and stopped. The engine failed to start upon subsequent attempts. The injection was then advanced by 3.5° (i.e. 33.5° BTDC). The engine ran smoothly on this timing butseemed to incur penalty on fuel consumption especially at high load levels.

  18. Reanalysis of the Gas-cooled fast reactor experiments at the zero power facility Proteus – Spectral indices

    Directory of Open Access Journals (Sweden)

    Girardin G.

    2013-03-01

    Full Text Available PROTEUS is a zero power reactor at the Paul Scherrer Institute which has been employed during the 1970’s to study experimentally the physics of the gas-cooled fast reactor. Reaction rate distributions, flux spectrum and reactivity effects have been measured in several configurations featuring PuO2/UO2 fuel, absorbers, large iron shields, and thorium oxide and thorium metal fuel either distributed quasihomogeneously in the reference PuO2/UO2 lattice or introduced in the form of radial and axial blanket zones. This papers focus on the spectral indices – including fission and capture in 232Th and 237Np - measured in the reference PuO2/UO2 lattices and their predictions with an MCNPX model specially developed for the PROTEUS-GCFR core. Predictions were obtained with JEFF-3.1 and -3.11, ENDF/B-VII.0 and VII.1, and JENDL-3.3 and -4.0. A general good agreement was demonstrated. The ratio of 232Th fission to 239Pu fission, however, was under-predicted by 8.7±2.1% and 6.5±2.1% using ENDF/B-VII.0 and VII.1, respectively. Finally, the capture rates in 237Np tended to be underpredicted by the JEFF and JENDL libraries, although the new cross section in JEFF-3.1.1 slightly improved the 237Np capture to 239Pu fission results (3.4±2.4%.

  19. Reliability study of a special decay heat removal system of a gas-cooled fast reactor demonstrator

    Energy Technology Data Exchange (ETDEWEB)

    Burgazzi, Luciano, E-mail: luciano.burgazzi@enea.it

    2014-12-15

    The European roadmap toward the development of generation IV concepts addresses the safety and reliability assessment of the special system designed for decay heat removal of a gas-cooled fast reactor demonstrator (GFRD). The envisaged system includes the combination of both active and passive means to accomplish the fundamental safety function. Failure probabilities are calculated on various system configurations, according to either pressurized or depressurized accident events under investigation, and integrated with probabilities of occurrence of corresponding hardware components and natural circulation performance assessment. The analysis suggests the improvement of measures against common cause failures (CCF), in terms of an appropriate diversification among the redundant systems, to reduce the system failure risk. Particular emphasis is placed upon passive system reliability assessment, being recognized to be still an open issue, and the approach based on the functional reliability is adopted to address the point. Results highlight natural circulation as a challenging factor for the decay heat removal safety function accomplishment by means of passive devices. With the models presented here, the simplifying assumptions and the limited scenarios considered according to the level of definition of the design, where many systems are not yet established, one can conclude that attention has to be paid to the functional aspects of the passive system, i.e. the ones not pertaining to the “hardware” of the system. In this article the results of the analysis are discussed, where the effects of the analytical assumptions, design options, accident managements on the reliability are examined. The design diversity of the components undergoing CCFs can be effective for the improvement and some accident management measures are also possible by making use of the long grace period in GFRD.

  20. Saturated Adaptive Output-Feedback Power-Level Control for Modular High Temperature Gas-Cooled Reactors

    Directory of Open Access Journals (Sweden)

    Zhe Dong

    2014-11-01

    Full Text Available Small modular reactors (SMRs are those nuclear fission reactors with electrical output powers of less than 300 MWe. Due to its inherent safety features, the modular high temperature gas-cooled reactor (MHTGR has been seen as one of the best candidates for building SMR-based nuclear plants with high safety-level and economical competitive power. Power-level control is crucial in providing grid-appropriation for all types of SMRs. Usually, there exists nonlinearity, parameter uncertainty and control input saturation in the SMR-based plant dynamics. Motivated by this, a novel saturated adaptive output-feedback power-level control of the MHTGR is proposed in this paper. This newly-built control law has the virtues of having relatively neat form, of being strong adaptive to parameter uncertainty and of being able to compensate control input saturation, which are given by constructing Lyapunov functions based upon the shifted-ectropies of neutron kinetics and reactor thermal-hydraulics, giving an online tuning algorithm for the controller parameters and proposing a control input saturation compensator respectively. It is proved theoretically that input-to-state stability (ISS can be guaranteed for the corresponding closed-loop system. In order to verify the theoretical results, this new control strategy is then applied to the large-range power maneuvering control for the MHTGR of the HTR-PM plant. Numerical simulation results show not only the relationship between regulating performance and control input saturation bound but also the feasibility of applying this saturated adaptive control law practically.

  1. Advanced coal-fueled industrial cogeneration gas turbine system. Annual report, June 1990--June 1991

    Energy Technology Data Exchange (ETDEWEB)

    LeCren, R.T.; Cowell, L.H.; Galica, M.A.; Stephenson, M.D.; Wen, C.S.

    1991-07-01

    Advances in coal-fueled gas turbine technology over the past few years, together with recent DOE-METC sponsored studies, have served to provide new optimism that the problems demonstrated in the past can be economically resolved and that the coal-fueled gas turbine can ultimately be the preferred system in appropriate market application sectors. The objective of the Solar/METC program is to prove the technical, economic, and environmental feasibility of a coal-fired gas turbine for cogeneration applications through tests of a Centaur Type H engine system operated on coal fuel throughout the engine design operating range. The five-year program consists of three phases, namely: (1) system description; (2) component development; (3) prototype system verification. A successful conclusion to the program will initiate a continuation of the commercialization plan through extended field demonstration runs.

  2. 冰蓄冷技术应用于燃气轮发电机进气冷却%Economic and Technology Analysis of Application of Ice Thermal Storage Technology to Inlet-air of Gas-turbine Cooling

    Institute of Scientific and Technical Information of China (English)

    曾淼; 叶水泉; 董兴杰; 陈永林

    2002-01-01

    Gas-turbine is constant flow engine, its power is direct proportion of air mass flow. Reducing the inlet-airtemperature will increase the output of gas-turbine. This paper analyzed the feasibility of the application of ice-thernal storagetechnology to inlet-air of gas-turbine cooling. It concludes that this application is feasible on both technology and economicsides.

  3. Investigation of austenitic alloys for advanced heat recovery and hot gas cleanup systems

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, R.W.; Ren, W.

    1996-06-01

    The objective of the research is to provide databases and design criteria to assist in the selection of optimum alloys for construction of components needed to contain process streams in advanced heat recovery and hot-gas cleanup systems. Typical components include: steam line piping and superheater tubing for low emission boilers (600 to 700{degrees}C), heat exchanger tubing for advanced steam cycles and topping cycle systems (650 to 800{degrees}C), foil materials for recuperators, on advanced turbine systems (700 to 750{degrees}C), and tubesheets for barrier filters, liners for piping, cyclones, and blowback system tubing for hot-gas cleanup systems (850 to 1000{degrees}C). The materials being examined fall into several classes, depending on which of the advanced heat recovery concepts is of concern. These classes include martensitic steels for service to 650{degrees}C, lean stainless steels and modified 25Cr-30Ni steels for service to 700{degrees}C, modified 25Cr-20Ni steels for service to 900{degrees}C, and high Ni-Cr-Fe or Ni-Cr-Co-Fe alloys for service to 1000{degrees}C.

  4. Advanced simulations of energy demand and indoor climate of passive ventilation systems with heat recovery and night cooling

    DEFF Research Database (Denmark)

    Hviid, Christian Anker; Svendsen, Svend

    with little energy consumption and with satisfying indoor climate. The concept is based on using passive measures like stack and wind driven ventilation, effective night cooling and low pressure loss heat recovery using two fluid coupled water-to-air heat exchangers developed at the Technical University......In building design the requirements for energy consumption for ventilation, heating and cooling and the requirements for increasingly better indoor climate are two opposing factors. This paper presents the schematic layout and simulation results of an innovative multifunctional ventilation concept...... of Denmark. Through building integration in high performance offices the system is optimized to incorporate multiple functions like heating, cooling and ventilation, thus saving the expenses of separate cooling and heating systems. The simulation results are derived using the state-of-the-art building...

  5. Gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ok Ryong

    2004-01-15

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  6. Using Cool Roofs to Reduce Energy Use, Greenhouse Gas Emissions, and Urban Heat-island Effects: Findings from an India Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Xu, Tengfang; Taha, Haider; Wray, Craig; Sathaye, Jayant; Garg, Vishal; Tetali, Surekha; Babu, M. Hari; Reddy, K. Niranjan

    2011-05-25

    Cool roofs, cool pavements, and urban vegetation reduce energy use in buildings, lower local air pollutant concentrations, and decrease greenhouse gas emissions from urban areas. This report summarizes the results of a detailed monitoring project in India and related simulations of meteorology and air quality in three developing countries. The field results quantified direct energy savings from installation of cool roofs on individual commercial buildings. The measured annual energy savings potential from roof-whitening of previously black roofs ranged from 20-22 kWh/m2 of roof area, corresponding to an air-conditioning energy use reduction of 14-26% in commercial buildings. The study estimated that typical annual savings of 13-14 kWh/m2 of roof area could be achieved by applying white coating to uncoated concrete roofs on commercial buildings in the Metropolitan Hyderabad region, corresponding to cooling energy savings of 10-19%. With the assumption of an annual increase of 100,000 square meters of new roof construction for the next 10 years in the Metropolitan Hyderabad region, the annual cooling energy savings due to whitening concrete roof would be 13-14 GWh of electricity in year ten alone, with cumulative 10-year cooling energy savings of 73-79 GWh for the region. The estimated savings for the entire country would be at least 10 times the savings in Hyderabad, i.e., more than 730-790 GWh. We estimated that annual direct CO2 reduction associated with reduced energy use would be 11-12 kg CO2/m2 of flat concrete roof area whitened, and the cumulative 10-year CO2 reduction would be approximately 0.60-0.65 million tons in India. With the price of electricity estimated at seven Rupees per kWh, the annual electricity savings on air-conditioning would be approximately 93-101 Rupees per m2 of roof. This would translate into annual national savings of approximately one billion Rupees in year ten, and cumulative 10-year savings of over five billion Rupees for cooling

  7. Technical analysis of a river basin-based model of advanced power plant cooling technologies for mitigating water management challenges

    Energy Technology Data Exchange (ETDEWEB)

    Stillwell, Ashlynn S [Department of Civil, Architectural, and Environmental Engineering, University of Texas at Austin, 1 University Station C1786, Austin, TX 78712 (United States); Clayton, Mary E; Webber, Michael E, E-mail: ashlynn.stillwell@mail.utexas.edu, E-mail: mclayton34@mail.utexas.edu, E-mail: webber@mail.utexas.edu [Department of Mechanical Engineering, University of Texas at Austin, 1 University Station C2200, Austin, TX 78712 (United States)

    2011-07-15

    Thermoelectric power plants require large volumes of water for cooling, which can introduce drought vulnerability and compete with other water needs. Alternative cooling technologies, such as cooling towers and hybrid wet-dry or dry cooling, present opportunities to reduce water diversions. This case study uses a custom, geographically resolved river basin-based model for eleven river basins in the state of Texas (the Brazos and San Jacinto-Brazos, Colorado and Colorado-Brazos, Cypress, Neches, Nueces, Red, Sabine, San Jacinto, and Trinity River basins), focusing on the Brazos River basin, to analyze water availability during drought. We utilized two existing water availability models for our analysis: (1) the full execution of water rights-a scenario where each water rights holder diverts the full permitted volume with zero return flow, and (2) current conditions-a scenario reflecting actual diversions with associated return flows. Our model results show that switching the cooling technologies at power plants in the eleven analyzed river basins to less water-intensive alternative designs can potentially reduce annual water diversions by 247-703 million m{sup 3}-enough water for 1.3-3.6 million people annually. We consider these results in a geographic context using geographic information system tools and then analyze volume reliability, which is a policymaker's metric that indicates the percentage of total demand actually supplied over a given period. This geographic and volume reliability analysis serves as a measure of drought susceptibility in response to changes in thermoelectric cooling technologies. While these water diversion savings do not alleviate all reliability concerns, the additional streamflow from the use of dry cooling alleviates drought concerns for some municipal water rights holders and might also be sufficient to uphold instream flow requirements for important bays and estuaries on the Texas Gulf coast.

  8. Dopant-assisted negative photoionization Ion mobility spectrometry coupled with on-line cooling inlet for real-time monitoring H2S concentration in sewer gas.

    Science.gov (United States)

    Peng, Liying; Jiang, Dandan; Wang, Zhenxin; Hua, Lei; Li, Haiyang

    2016-06-01

    Malodorous hydrogen sulfide (H2S) gas often exists in the sewer system and associates with the problems of releasing the dangerous odor to the atmosphere and causing sewer pipe to be corroded. A simple method is in demand for real-time measuring H2S level in the sewer gas. In this paper, an innovated method based on dopant-assisted negative photoionization ion mobility spectrometry (DANP-IMS) with on-line semiconductor cooling inlet was put forward and successfully applied for the real-time measurement of H2S in sewer gas. The influence of moisture was effectively reduced via an on-line cooling method and a non-equilibrium dilution with drift gas. The limits of quantitation for the H2S in ≥60% relative humidity air could be obtained at ≤79.0ng L(-1) with linear ranges of 129-2064ng L(-1). The H2S concentration in a sewer manhole was successfully determined while its product ions were identified by an ion-mobility time-of-fight mass spectrometry. Finally, the correlation between sewer H2S concentration and the daily routines and habits of residents was investigated through hourly or real-time monitoring the variation of sewer H2S in manholes, indicating the power of this DANP-IMS method in assessing the H2S concentration in sewer system.

  9. Advanced diagnostics for impact-flash spectroscopy on light-gas guns.

    Energy Technology Data Exchange (ETDEWEB)

    Breiland, William George; Reinhart, William Dodd; Miller, Paul Albert; Brown, Justin L.; Thornhill, Tom Finley, III (,; ); Mangan, Michael A.; Shaner, Eric Arthur; Chhabildas, Lalit Chandra; Grine, Albert D.; Wanke, Michael Clement; Alexander, C. Scott

    2007-03-01

    This study is best characterized as new technology development for implementing new sensors to investigate the optical characteristics of a rapidly expanding debris cloud resulting from hypervelocity impact regimes of 7 to 11 km/s. Our gas guns constitute a unique test bed that match operational conditions relevant to hypervelocity impact encountered in space engagements. We have demonstrated the use of (1) terahertz sensors, (2) silicon diodes for visible regimes, (3) germanium and InGaAs sensors for the near infrared regimes, and (4) the Sandia lightning detectors which are similar to the silicon diodes described in 2. The combination and complementary use of all these techniques has the strong potential of ''thermally'' characterizing the time dependent behavior of the radiating debris cloud. Complementary spectroscopic measurements provide temperature estimates of the impact generated debris by fitting its spectrum to a blackbody radiation function. This debris is time-dependent as its transport/expansion behavior is changing with time. The rapid expansion behavior of the debris cools the cloud rapidly, changing its thermal/temperature characteristics with time. A variety of sensors that span over a wide spectrum, varying from visible regime to THz frequencies, now gives us the potential to cover the impact over a broader temporal regime starting from high pressures (Mbar) high-temperatures (eV) to low pressures (mbar) low temperatures (less than room temperature) as the debris expands and cools.

  10. Advances in Inhalation Gas Dosimetry for Derivation of a Reference Concentration (RfC) and Use in Risk Assessment

    Science.gov (United States)

    This status report provides a review of advances in the state of the science for interspecies inhalation gas dosimetry related to extrathoracic (ET) or upper respiratory tract (URT), tracheobronchial (TB), pulmonary (PU), and extrarespiratory (systemic, SYS) effects.

  11. Advances in gas content based on outburst control technology in Huainan, China

    Institute of Scientific and Technical Information of China (English)

    Xue Sheng; Yuan Liang; Xie Jun; Wang Yucang

    2014-01-01

    The sudden and violent nature of coal and gas outbursts continues to pose a serious threat to coal mine safety in China. One of the key issues is to predict the occurrence of outbursts. Current methods that are used for predicting the outbursts in China are considered to be inadequate, inappropriate or impractical in some seam conditions. In recent years, Huainan Mining Industry Group (Huainan) in China and the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia have been jointly developing technology based on gas content in coal seams to predict the occurrence of outbursts in Hua-inan. Significant progresses in the technology development have been made, including the development of a more rapid and accurate system in determining gas content in coal seams, the invention of a sam-pling-while-drilling unit for fast and pointed coal sampling, and the coupling of DEM and LBM codes for advanced numerical simulation of outburst initiation and propagation. These advances are described in this paper.

  12. Melt Infiltrated Ceramic Matrix Composites for Shrouds and Combustor Liners of Advanced Industrial Gas Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Gregory Corman; Krishan Luthra; Jill Jonkowski; Joseph Mavec; Paul Bakke; Debbie Haught; Merrill Smith

    2011-01-07

    This report covers work performed under the Advanced Materials for Advanced Industrial Gas Turbines (AMAIGT) program by GE Global Research and its collaborators from 2000 through 2010. A first stage shroud for a 7FA-class gas turbine engine utilizing HiPerComp{reg_sign}* ceramic matrix composite (CMC) material was developed. The design, fabrication, rig testing and engine testing of this shroud system are described. Through two field engine tests, the latter of which is still in progress at a Jacksonville Electric Authority generating station, the robustness of the CMC material and the shroud system in general were demonstrated, with shrouds having accumulated nearly 7,000 hours of field engine testing at the conclusion of the program. During the latter test the engine performance benefits from utilizing CMC shrouds were verified. Similar development of a CMC combustor liner design for a 7FA-class engine is also described. The feasibility of using the HiPerComp{reg_sign} CMC material for combustor liner applications was demonstrated in a Solar Turbines Ceramic Stationary Gas Turbine (CSGT) engine test where the liner performed without incident for 12,822 hours. The deposition processes for applying environmental barrier coatings to the CMC components were also developed, and the performance of the coatings in the rig and engine tests is described.

  13. DESIGN, FABRICATION, AND TESTING OF AN ADVANCED, NON-POLLUTING TURBINE DRIVE GAS GENERATOR

    Energy Technology Data Exchange (ETDEWEB)

    Stephen E. Doyle

    2002-12-31

    The objectives of this report period were to continue and complete testing of the Gas Generator hardware, to complete and submit a Draft Final Report, and after incorporation of adjustments required, to then submit the Final Report. Focus during this report period was initially on testing the Gas Generator. While conducting scheduled full power tests of the Gas Generator at the facilities of the testing sub-contractor, National Testing Services [NTS], in Santa Clarita CA, anomalies in the performance of the Gas Generator were discovered. All testing was stopped on November 6, 2002. An expert team was formed to evaluate the anomalies and to recommend any appropriate corrective actions. After extensive analyses of the actual hardware, the test data acquired and recorded during testing, and a review of the test facilities and procedures, the Anomalies Review Team recommended that CES modify the combustion chamber front end cooling method and modify the configuration of the diluent injectors downstream of the combustion chamber, to eliminate the anomalies. At a review meeting convened in Sacramento CA on November 23, 2002, outside experts from the Lawrence Livermore National Laboratory, Air Liquide's Research Center in Chicago IL, and the California Energy Commission, confirmed that the expert team's assessed cause of the problem was the likely cause, and the recommended corrective actions were appropriate. Modified hardware drawings were produced in late November-early December 2002, hardware fabrication was begun in December, and was in process at the end of December. Also during December, the NTS test facility was being adjusted to take account of the modified hardware configuration being produced. All work was aimed toward realizing a schedule of resumed testing by mid-January for completion of tests by end of January or early February, 2003. Original objectives of the program remain in place and approximately ninety (90) percent of those objectives had

  14. Numerical Simulation of Plasma-Dynamical Processes in the Technological Inductively Coupled RF Plasmatron with Gas Cooling

    Directory of Open Access Journals (Sweden)

    Yu. M. Grishin

    2016-01-01

    Full Text Available The electrodeless inductively coupled RF plasmatron (ICP torches became widely used in various fields of engineering, science and technology. Presently, owing to development of new technologies to produce very pure substances, nanopowders, etc., there is a steadily increasing interest in the induction plasma. This generates a need for a broad range of theoretical and experimental studies to optimize the design and technological parameters of different ICP equipment.The paper presents a numerical model to calculate parameters of inductively coupled RF plasmatron with gas-cooling flow. A finite volume method is used for a numerical solution of a system of Maxwell's and heat transfer equations in the application package ANSYS CFX (14.5. The pseudo-steady approach to solving problems is used.A numerical simulation has been computed in the application package ANSYS CFX (14.5 for a specific design option of the technological ICP, which has a three-coils inductor and current amplitude in the range J к = 50-170 A (3 MHz. The pure argon flows in the ICP. The paper discusses how the value of discharge current impacts on the thermodynamic parameters (pressure, temperature and the power energy in discharge zone. It shows that the ICP can generate a plasma stream with a maximum temperature of about 10 kK and an output speed of 10-15 m/s. The work determines a length of the plasma stream with a weight average temperature of more than 4 kK. It has been found that in order to keep the quartz walls in normal thermal state, the discharge current amplitude should not exceed 150 A. The paper shows the features of the velocity field distribution in the channel of the plasma torch, namely, the formation of vortex in the position of the first coil. The results obtained are important for calculating the dynamics of heating and evaporation of quartz particles in the manufacturing processes for plasma processing of quartz concentrate into high-purity quartz and

  15. Metal-Poor, Cool Gas in the Circumgalactic Medium of a z = 2.4 Star-Forming Galaxy: Direct Evidence for Cold Accretion?

    CERN Document Server

    Crighton, Neil H M; Prochaska, J Xavier

    2013-01-01

    In our current galaxy formation paradigm, high-redshift galaxies are predominantly fuelled by accretion of cool, metal-poor gas from the intergalactic medium. Hydrodynamical simulations predict that this material should be observable in absorption against background sightlines within a galaxy's virial radius, as optically thick Lyman-limit systems (LLSs) with low metallicities. Here we report the discovery of exactly such a strong metal-poor absorber at an impact parameter R_perp = 58 kpc from a star-forming galaxy at z = 2.44. Besides strong neutral hydrogen [N(HI) = 10^(19.50 +/- 0.16) cm^-2] we detect neutral deuterium and oxygen, allowing a precise measurement of the metallicity: log10(Z / Zsolar) = -2.0 +/- 0.17, or (7-15) x 10^-3 solar. Furthermore, the narrow deuterium linewidth requires a cool temperature 0.1 solar, ten times larger than the metal-poor component. We conclude that the photoionized circumgalactic medium (CGM) of this galaxy is highly inhomogeneous: the majority of the gas is in a cool,...

  16. Development of Natural Gas Fired Combined Cycle Plant for Tri-Generation of Power, Cooling and Clean Water Using Waste Heat Recovery: Techno-Economic Analysis

    Directory of Open Access Journals (Sweden)

    Gowtham Mohan

    2014-10-01

    Full Text Available Tri-generation is one of the most efficient ways for maximizing the utilization of available energy. Utilization of waste heat (flue gases liberated by the Al-Hamra gas turbine power plant is analyzed in this research work for simultaneous production of: (a electricity by combining steam rankine cycle using heat recovery steam generator (HRSG; (b clean water by air gap membrane distillation (AGMD plant; and (c cooling by single stage vapor absorption chiller (VAC. The flue gases liberated from the gas turbine power cycle is the prime source of energy for the tri-generation system. The heat recovered from condenser of steam cycle and excess heat available at the flue gases are utilized to drive cooling and desalination cycles which are optimized based on the cooling energy demands of the villas. Economic and environmental benefits of the tri-generation system in terms of cost savings and reduction in carbon emissions were analyzed. Energy efficiency of about 82%–85% is achieved by the tri-generation system compared to 50%–52% for combined cycles. Normalized carbon dioxide emission per MW·h is reduced by 51.5% by implementation of waste heat recovery tri-generation system. The tri-generation system has a payback period of 1.38 years with cumulative net present value of $66 million over the project life time.

  17. Metal-poor, Cool Gas in the Circumgalactic Medium of a z = 2.4 Star-forming Galaxy: Direct Evidence for Cold Accretion?

    Science.gov (United States)

    Crighton, Neil H. M.; Hennawi, Joseph F.; Prochaska, J. Xavier

    2013-10-01

    In our current galaxy formation paradigm, high-redshift galaxies are predominantly fueled by accretion of cool, metal-poor gas from the intergalactic medium. Hydrodynamical simulations predict that this material should be observable in absorption against background sightlines within a galaxy's virial radius, as optically thick Lyman limit systems (LLSs) with low metallicities. Here we report the discovery of exactly such a strong metal-poor absorber at an impact parameter R = 58 kpc from a star-forming galaxy at z = 2.44. Besides strong neutral hydrogen (N_{{H}^0}=10^{19.50+/- 0.16}\\, cm^{-2}) we detect neutral deuterium and oxygen, allowing a precise measurement of the metallicity: log10(Z/Z ⊙) = -2.0 ± 0.17, or (7-15) × 10-3 solar. Furthermore, the narrow deuterium linewidth requires a cool temperature 0.1 solar, 10 times larger than the metal-poor component. We conclude that the photoionized circumgalactic medium (CGM) of this galaxy is highly inhomogeneous: the majority of the gas is in a cool, metal-poor and predominantly neutral phase, but the majority of the metals are in a highly ionized phase exhibiting weak neutral hydrogen absorption but strong metal absorption. If such inhomogeneity is common, then high-resolution spectra and detailed ionization modeling are critical to accurately appraise the distribution of metals in the high-redshift CGM. .

  18. Effect of thermal barrier coatings on the performance of steam and water-cooled gas turbine/steam turbine combined cycle system

    Science.gov (United States)

    Nainiger, J. J.

    1978-01-01

    An analytical study was made of the performance of air, steam, and water-cooled gas-turbine/steam turbine combined-cycle systems with and without thermal-barrier coatings. For steam cooling, thermal barrier coatings permit an increase in the turbine inlet temperature from 1205 C (2200 F), resulting in an efficiency improvement of 1.9 percentage points. The maximum specific power improvement with thermal barriers is 32.4 percent, when the turbine inlet temperature is increased from 1425 C (2600 F) to 1675 C (3050 F) and the airfoil temperature is kept the same. For water cooling, the maximum efficiency improvement is 2.2 percentage points at a turbine inlet temperature of 1683 C (3062 F) and the maximum specific power improvement is 36.6 percent by increasing the turbine inlet temperature from 1425 C (2600 F) to 1730 C (3150 F) and keeping the airfoil temperatures the same. These improvements are greater than that obtained with combined cycles using air cooling at a turbine inlet temperature of 1205 C (2200 F). The large temperature differences across the thermal barriers at these high temperatures, however, indicate that thermal stresses may present obstacles to the use of coatings at high turbine inlet temperatures.

  19. Effect of Turbulence Intensity on Cross-Injection Film Cooling at a Stepped or Smooth Endwall of a Gas Turbine Vane Passage

    Directory of Open Access Journals (Sweden)

    Pey-Shey Wu

    2014-01-01

    Full Text Available This study is concerned with a film cooling technique applicable to the protection of the endwalls of a gas turbine vane. In the experiments, cross-injection coolant flow from two-row, paired, inclined holes with nonintersecting centerlines was utilized. The test model is a scaled two-half vane. The levels of turbulence intensity used in the experiments are T.I.=1.8%, 7%, and 12%. Other parameters considered in the film cooling experiments include three inlet Reynolds numbers (9.20×104 , 1.24×105, and  1.50×105, three blowing ratios (0.5, 1.0, and 2.0, and three endwall conditions (smooth endwall and stepped endwall with forward-facing or backward-facing step. Thermochromic liquid crystal (TLC technique with steady-state heat transfer experiments was used to obtain the whole-field film cooling effectiveness. Results show that, at low turbulence intensity, increasing Reynolds number decreases the effectiveness in most of the vane passage. There is no monotonic trend of influence by Reynolds number at high turbulence intensity. The effect of blowing ratio on the effectiveness has opposite trends at low and high turbulence levels. Increasing turbulent intensity decreases the effectiveness, especially near the inlet of the vane passage. With a stepped endwall, turbulence intensity has only mild effect on the film cooling effectiveness.

  20. Effect of turbulence intensity on cross-injection film cooling at a stepped or smooth endwall of a gas turbine vane passage.

    Science.gov (United States)

    Wu, Pey-Shey; Tsai, Shen-Ta; Jhuo, Yue-Hua

    2014-01-01

    This study is concerned with a film cooling technique applicable to the protection of the endwalls of a gas turbine vane. In the experiments, cross-injection coolant flow from two-row, paired, inclined holes with nonintersecting centerlines was utilized. The test model is a scaled two-half vane. The levels of turbulence intensity used in the experiments are T.I. = 1.8%, 7%, and 12%. Other parameters considered in the film cooling experiments include three inlet Reynolds numbers (9.20 × 10(4), 1.24 × 10(5), and 1.50 × 10(5)), three blowing ratios (0.5, 1.0, and 2.0), and three endwall conditions (smooth endwall and stepped endwall with forward-facing or backward-facing step). Thermochromic liquid crystal (TLC) technique with steady-state heat transfer experiments was used to obtain the whole-field film cooling effectiveness. Results show that, at low turbulence intensity, increasing Reynolds number decreases the effectiveness in most of the vane passage. There is no monotonic trend of influence by Reynolds number at high turbulence intensity. The effect of blowing ratio on the effectiveness has opposite trends at low and high turbulence levels. Increasing turbulent intensity decreases the effectiveness, especially near the inlet of the vane passage. With a stepped endwall, turbulence intensity has only mild effect on the film cooling effectiveness.

  1. Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial

    Science.gov (United States)

    Irvalı, Nil; Ninnemann, Ulysses S.; Kleiven, Helga (Kikki) F.; Galaasen, Eirik V.; Morley, Audrey; Rosenthal, Yair

    2016-10-01

    High-resolution lithic and sea surface climate records are used to portray the progression of North Atlantic climate, hydrography, and Greenland Ice Sheet (GIS) activity through the peak of Marine Isotope Stage (MIS) 5e into the last glacial inception. We use Eirik Drift sediment core MD03-2664 (57°26.34‧N, 48°36.35‧W), recovered south of Greenland, strategically located to monitor fluctuations in GIS extent and iceberg calving events. Our results show that a significant amount of ice-rafted debris (IRD) was present during the early MIS 5e, until gradually tapering off by 122 kyr BP due to a diminishing GIS. Sea surface temperatures (SSTs) in the northern subpolar gyre reached peak values early in MIS 5e coinciding with peak insolation. Regional cooling leading to the demise of the last interglacial started prior to the end of the MIS 5e benthic δ18O plateau, at approximately 119 kyr BP, as summer insolation waned. This gradual cooling trend is interrupted by an abrupt and brief cooling episode at ∼117 kyr BP. Increased IRD abundance during the 117 kyr BP cooling event suggests that regional ice sheet growth occurred prior to the end of the MIS 5e benthic δ18O plateau, and the major glacial inception. SSTs south of Greenland followed a two-step cooling during the glacial inception similar to the pattern observed across much of the North Atlantic and Europe. Benthic δ18O increases in parallel, suggesting that this two-step cooling is linked to a two-phased intensification of Northern Hemisphere glaciation.

  2. Implications of Results from the Advanced Gas Reactor Fuel Development and Qualification Program on Licensing of Modular HTGRs

    Energy Technology Data Exchange (ETDEWEB)

    David Petti

    2001-10-01

    The high level of safety of modular high temperature gas-cooled reactor (HTGR) designs is achieved by passively maintaining core temperatures below fission product release thresholds under all envisioned accident scenarios. This level of fuel performance and fission product retention reduces the radioactive source term by many orders of magnitude relative to other reactor types but is predicated on exceptionally high coated-particle fuel fabrication quality and excellent fuel performance under normal operation and accident conditions. The Advanced Gas Reactor Fuel Development and Qualification (AGR) Program decided to qualify for uranium oxide/uranium carbide (UCO) TRISO coated-particle fuel in an operating envelope that would bound both pebble bed and prismatic modular HTGR options. By using a mixture of uranium oxide and uranium carbide, the kernel composition is engineered to minimize CO formation and fuel kernel migration, which is key to maintain to fuel integrity at the higher burnups, temperatures, and temperature gradients anticipated in prismatic HTGRs. Fuel fabrication conducted at both laboratory and engineering scale has demonstrated the ability to fabricate high quality UCO TRISO fuel with very low defects. The first irradiation (AGR 1) exposed about 300,000 TRISO fuel particles to a peak burnup of 19.6% FIMA, a peak fast-neutron fluence of about 4.3 × 1025 n/m2, and a maximum time-averaged fuel temperature of about 1,200°C without a single particle failure. The very low release of key metallic fission products (except silver) measured in post-irradiation examination (PIE) confirms the excellent performance measured under irradiation. Very low releases have been measured in accident simulation heatup testing (''safety testing'') after hundreds of hours at 1600 and 1700°C and no particle failures (no noble gas release measured) have been observed. Even after hundreds of hours at 1800°C, the releases are

  3. Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors. Publishable Final Activity Report

    Energy Technology Data Exchange (ETDEWEB)

    Kuijper, J.C., E-mail: kuijper@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Somers, J.; Van Den Durpel, L.; Chauvet, V.; Cerullo, N.; Cetnar, J.; Abram, T.; Bakker, K.; Bomboni, E.; Bernnat, W.; Domanska, J.G.; Girardi, E.; De Haas, J.B.M.; Hesketh, K.; Hiernaut, J.P.; Hossain, K.; Jonnet, J.; Kim, Y.; Kloosterman, J.L.; Kopec, M.; Murgatroyd, J.; Millington, D.; Lecarpentier, D.; Lomonaco, G.; McEachern, D.; Meier, A.; Mignanelli, M.; Nabielek, H.; Oppe, J.; Petrov, B.Y.; Pohl, C.; Ruetten, H.J.; Schihab, S.; Toury, G.; Trakas, C.; Venneri, F.; Verfondern, K.; Werner, H.; Wiss, T.; Zakova, J.

    2010-11-15

    The PUMA project -the acronym stands for 'Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors'- was a Specific Targeted Research Project (STREP) within the EURATOM 6th Framework Program (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO{sub 2}-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR

  4. Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors. Publishable Final Activity Report

    Energy Technology Data Exchange (ETDEWEB)

    Kuijper, J.C., E-mail: kuijper@nrg.eu [Nuclear Research and Consultancy Group (NRG), Petten (Netherlands); Somers, J.; Van Den Durpel, L.; Chauvet, V.; Cerullo, N.; Cetnar, J.; Abram, T.; Bakker, K.; Bomboni, E.; Bernnat, W.; Domanska, J.G.; Girardi, E.; De Haas, J.B.M.; Hesketh, K.; Hiernaut, J.P.; Hossain, K.; Jonnet, J.; Kim, Y.; Kloosterman, J.L.; Kopec, M.; Murgatroyd, J.; Millington, D.; Lecarpentier, D.; Lomonaco, G.; McEachern, D.; Meier, A.; Mignanelli, M.; Nabielek, H.; Oppe, J.; Petrov, B.Y.; Pohl, C.; Ruetten, H.J.; Schihab, S.; Toury, G.; Trakas, C.; Venneri, F.; Verfondern, K.; Werner, H.; Wiss, T.; Zakova, J.

    2010-11-15

    The PUMA project -the acronym stands for 'Plutonium and Minor Actinide Management in Thermal High-Temperature Gas-Cooled Reactors'- was a Specific Targeted Research Project (STREP) within the EURATOM 6th Framework Program (EU FP6). The PUMA project ran from September 1, 2006, until August 31, 2009, and was executed by a consortium of 14 European partner organisations and one from the USA. This report serves 2 purposes. It is both the 'Publishable Final Activity Report' and the 'Final (Summary) Report', describing, per Work Package, the specific objectives, research activities, main conclusions, recommendations and supporting documents. PUMA's main objective was to investigate the possibilities for the utilisation and transmutation of plutonium and especially minor actinides in contemporary and future (high temperature) gas-cooled reactor designs, which are promising tools for improving the sustainability of the nuclear fuel cycle. This contributes to the reduction of Pu and MA stockpiles, and also to the development of safe and sustainable reactors for CO{sub 2}-free energy generation. The PUMA project has assessed the impact of the introduction of Pu/MA-burning HTRs at three levels: fuel and fuel performance (modelling), reactor (transmutation performance and safety) and reactor/fuel cycle facility park. Earlier projects already indicated favourable characteristics of HTRs with respect to Pu burning. So, core physics of Pu/MA fuel cycles for HTRs has been investigated to study the CP fuel and reactor characteristics and to assure nuclear stability of a Pu/MA HTR core, under both normal and abnormal operating conditions. The starting point of this investigation comprised the two main contemporary HTR designs, viz. the pebble-bed type HTR, represented by the South-African PBMR, and hexagonal block type HTR, represented by the GT-MHR. The results (once again) demonstrate the flexibility of the contemporary (and near future) HTR

  5. Selection of natural Gas Fired Advanced Turbine Systems (GFATS) program - Task 3. Topical report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-06-01

    Research continued on natural gas-fired turbines.The objective of Task 3 was to perform initial trade studies and select one engine system (Gas-Fired Advanced Turbine System [GFATS]) that the contractor could demonstrate, at full scale, in the 1998 to 2000 time frame. This report describes the results of the selection process. This task, including Allison internal management reviews of the selected system, has been completed. Allison`s approach to ATS is to offer an engine family that is based on the newest T406 high technology engine. This selection was based on a number of parameters including return on investment (ROI), internal rate of return (IRR) market size and potential sales into that market. This base engine family continues a history at Allison of converting flight engine products to industrial use.

  6. A technology development summary for the AGT101 Advanced Gas Turbine Program

    Energy Technology Data Exchange (ETDEWEB)

    Boyd, G.L.; Kidwell, J.R.; Kreiner, D.M.

    1987-01-01

    Since the program initiation in October 1979, the Garrett/Ford Advanced Gas Turbine Program, designated AGT101, has made significant progress in developing ceramic technology for gas turbine applications. Successful component development has resulted in engine tests with an all ceramic hot section to temperatures up to 2200F (1204C) and full speed operation to 100,000 rpm (turbine rotor tip speed of 2300 ft/sec (701 m/s)). An 85-hour test was performed on an all ceramic engine at 2200F (1204C) turbine inlet temperature. These engine tests represent important first steps in the development of ceramic materials and technology. Engine evaluation was preceded by important component development. Activities included aerodynamic component evaluation and development of a high temperature foil bearing to support the ceramic turbine rotor. Development of low leakage regenerator seals and static ceramic seals in this high temperature environment were critical to engine performance.

  7. Gas-phase advanced oxidation as an integrated air pollution control technique

    Directory of Open Access Journals (Sweden)

    Getachew A. Adnew

    2016-03-01

    Full Text Available Gas-phase advanced oxidation (GPAO is an emerging air cleaning technology based on the natural self-cleaning processes that occur in the Earth’s atmosphere. The technology uses ozone, UV-C lamps and water vapor to generate gas-phase hydroxyl radicals that initiate oxidation of a wide range of pollutants. In this study four types of GPAO systems are presented: a laboratory scale prototype, a shipping container prototype, a modular prototype, and commercial scale GPAO installations. The GPAO systems treat volatile organic compounds, reduced sulfur compounds, amines, ozone, nitrogen oxides, particles and odor. While the method covers a wide range of pollutants, effective treatment becomes difficult when temperature is outside the range of 0 to 80 °C, for anoxic gas streams and for pollution loads exceeding ca. 1000 ppm. Air residence time in the system and the rate of reaction of a given pollutant with hydroxyl radicals determine the removal efficiency of GPAO. For gas phase compounds and odors including VOCs (e.g. C6H6 and C3H8 and reduced sulfur compounds (e.g. H2S and CH3SH, removal efficiencies exceed 80%. The method is energy efficient relative to many established technologies and is applicable to pollutants emitted from diverse sources including food processing, foundries, water treatment, biofuel generation, and petrochemical industries.

  8. Pure Air`s advanced flue gas desulfurization clean coal project

    Energy Technology Data Exchange (ETDEWEB)

    Brown, J.R. [Pure Air Bailly Station, Chesterton, IN (United States)

    1998-12-31

    Pure Air`s Advanced Flue Gas Desulfurization (AFGD) Clean Coal Project successfully completed four and a half years of operation in December 1996 at Northern Indiana Public Service Company`s (NIPSCO) Bailly Generating Station. This project received a $60 million grant from the DOE Clean Coal II program. Included in this was a three year DOE demonstration period. The facility was designed, built and is owned and operated by Pure Air of Allentown, Pennsylvania, through its project company, Pure Air on the Lake, Limited Partnership. The project met or exceeded all performance criteria. It has averaged 95.3% SO{sub 2} removal, 99.9% availability and produced high quality commercial gypsum during this four and a half year period. It demonstrated many advanced technology features including a single, large absorber module serving two boilers, a wastewater evaporation system, an air rotary sparger for oxidation, and a new technology for agglomerating gypsum.

  9. THE COMPONENT TEST FACILITY – A NATIONAL USER FACILITY FOR TESTING OF HIGH TEMPERATURE GAS-COOLED REACTOR (HTGR) COMPONENTS AND SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    David S. Duncan; Vondell J. Balls; Stephanie L. Austad

    2008-09-01

    The Next Generation Nuclear Plant (NGNP) and other High-Temperature Gas-cooled Reactor (HTGR) Projects require research, development, design, construction, and operation of a nuclear plant intended for both high-efficiency electricity production and high-temperature industrial applications, including hydrogen production. During the life cycle stages of an HTGR, plant systems, structures and components (SSCs) will be developed to support this reactor technology. To mitigate technical, schedule, and project risk associated with development of these SSCs, a large-scale test facility is required to support design verification and qualification prior to operational implementation. As a full-scale helium test facility, the Component Test facility (CTF) will provide prototype testing and qualification of heat transfer system components (e.g., Intermediate Heat Exchanger, valves, hot gas ducts), reactor internals, and hydrogen generation processing. It will perform confirmation tests for large-scale effects, validate component performance requirements, perform transient effects tests, and provide production demonstration of hydrogen and other high-temperature applications. Sponsored wholly or in part by the U.S. Department of Energy, the CTF will support NGNP and will also act as a National User Facility to support worldwide development of High-Temperature Gas-cooled Reactor technologies.

  10. State-to-state vibrational kinetics of H$_2$ and H$_2^+$ in a post-shock cooling gas with primordial composition

    CERN Document Server

    Coppola, C M; Bruno, D; Esposito, F; Galli, D; Palla, F; Longo, S

    2016-01-01

    The radiative cooling of shocked gas with primordial chemical composition is an important process relevant to the formation of the first stars and structures, as well as taking place also in high velocity cloud collisions and supernovae explosions. Among the different processes that need to be considered, the formation kinetics and cooling of molecular hydrogen are of prime interest, since they provide the only way to lower the gas temperature to values well below $\\sim$10$^4$~K. In previous works, the internal energy level structure of H$_2$ and its cation has been treated in the approximation of rovibrational ground state at low densities, or trying to describe the dynamics using some arbitrary $v>0$ H$_2$ level that is considered representative of the excited vibrational manifold. In this study, we compute the vibrationally resolved kinetics for the time-dependent chemical and thermal evolution of the post-shock gas in a medium of primordial composition. The calculated non-equilibrium distributions are use...

  11. Rhapsody-G simulations I: the cool cores, hot gas and stellar content of massive galaxy clusters

    CERN Document Server

    Hahn, Oliver; Wu, Hao-Yi; Evrard, August E; Teyssier, Romain; Wechsler, Risa H

    2015-01-01

    We present the Rhapsody-G suite of cosmological hydrodynamic AMR zoom simulations of ten massive galaxy clusters at the $M_{\\rm vir}\\sim10^{15}\\,{\\rm M}_\\odot$ scale. These simulations include cooling and sub-resolution models for star formation and stellar and supermassive black hole feedback. The sample is selected to capture the whole gamut of assembly histories that produce clusters of similar final mass. We present an overview of the successes and shortcomings of such simulations in reproducing both the stellar properties of galaxies as well as properties of the hot plasma in clusters. In our simulations, a long-lived cool-core/non-cool core dichotomy arises naturally, and the emergence of non-cool cores is related to low angular momentum major mergers. Nevertheless, the cool-core clusters exhibit a low central entropy compared to observations, which cannot be alleviated by thermal AGN feedback. For cluster scaling relations we find that the simulations match well the $M_{500}-Y_{500}$ scaling of Planck ...

  12. Evaluation of Effect of N{sub 2} Gas on the Cooling Capability of Passive Auxiliary Feedwater System (PAFS) in APR+

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Yun Je; Kang, Kyong Ho; Yun, Byong Jo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    In Korea, Advanced Power Reactor Plus (APR+) has being developed by adding passive safety features to Advanced Power Reactor 1400MWe (APR1400). Passive Auxiliary Feedwater System (PAFS) is one of passive system adopted in the APR+ to replace the conventional active auxiliary feedwater system. Because PAFS removes decay heat from the reactor core, it is required to verify the performance of PAFS in postulated accidents cases. In addition, an effect of noncondensable gas on the heat removal capability of PAFS should be evaluated since the non-condensable gas may deteriorate a condensation heat transfer through the condensation heat exchanger in PAFS. In this study, the effect of N{sub 2} gas was evaluated using MARS

  13. Performance of cooling capacity adjustment in gas engine-driven heat pump%燃气机热泵容量调节制冷性能试验

    Institute of Scientific and Technical Information of China (English)

    王明涛; 刘焕卫; 张百浩

    2015-01-01

    Gas engine driven heat pump (GEHP), which mainly consists of a gas engine, an evaporator, a condenser and an expansion valve, can make full use of the waste heat from cylinder jacket and exhaust gas and achieve a higher primary energy ratio (PER) than other forms of heating/cooling systems, and therefore has been considered as a preferable choice in the air-conditioning scheme. Compared with the electric-driven heat pump (EHP), the GEHP has two distinguished advantages: 1) the ability to recover the gas engine waste heat from cylinder jacket and exhaust gas; 2) easy modulation of gas engine speed to meet the cooling loads. In the present article, a novel GEHP which could independently provide heating, cooling and hot water for the buildings was presented. The capacity adjustment and stable operation of GEHP could be achieved by controlling engine rotary speed. The goals of engine rotary speed control were to match the rotary speed and cooling/heating capacity, and keep robust to disturbance. In order to control engine rotary speed effectively, the engine rotary speed expert proportion-integration-differentiation (PID) controller was designed according to the engine rotary speed control knowledge base and the controlling rules in this study. Meanwhile, the energy analysis of GEHP was presented as well as the GEHP operating parameters (such as ambient air temperature, evaporator water flow and engine rotary speed). The engine rotary expert PID controller was applied to the engine rotary speed control in a GEHP system experimentally under different conditions (modulation on cooling loads and anti-disturbance), and the cooling performance characteristics of GEHP were investigated experimentally over a wide range of engine rotary speed (1 400-2 200 r/min). The performance of GEHP was characterized by cooling capacity, waste heat amount recovered, coefficient of performance (COP) and PER. The relationships between engine rotary speed and cooling capacity, waste heat

  14. METAL-POOR, COOL GAS IN THE CIRCUMGALACTIC MEDIUM OF A z = 2.4 STAR-FORMING GALAXY: DIRECT EVIDENCE FOR COLD ACCRETION?

    Energy Technology Data Exchange (ETDEWEB)

    Crighton, Neil H. M.; Hennawi, Joseph F. [Max-Planck-Institut für Astronomie, Königstuhl 17, Heidelberg D-69117 (Germany); Prochaska, J. Xavier, E-mail: neilcrighton@gmail.com [Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2013-10-20

    In our current galaxy formation paradigm, high-redshift galaxies are predominantly fueled by accretion of cool, metal-poor gas from the intergalactic medium. Hydrodynamical simulations predict that this material should be observable in absorption against background sightlines within a galaxy's virial radius, as optically thick Lyman limit systems (LLSs) with low metallicities. Here we report the discovery of exactly such a strong metal-poor absorber at an impact parameter R = 58 kpc from a star-forming galaxy at z = 2.44. Besides strong neutral hydrogen (N{sub H{sup 0}}=10{sup 19.50±0.16} cm{sup -2}) we detect neutral deuterium and oxygen, allowing a precise measurement of the metallicity: log{sub 10}(Z/Z {sub ☉}) = –2.0 ± 0.17, or (7-15) × 10{sup –3} solar. Furthermore, the narrow deuterium linewidth requires a cool temperature <20,000 K. Given the striking similarities between this system and the predictions of simulations, we argue that it represents the direct detection of a high-redshift cold-accretion stream. The low-metallicity gas cloud is a single component of an absorption system exhibiting a complex velocity, ionization, and enrichment structure. Two other components have metallicities >0.1 solar, 10 times larger than the metal-poor component. We conclude that the photoionized circumgalactic medium (CGM) of this galaxy is highly inhomogeneous: the majority of the gas is in a cool, metal-poor and predominantly neutral phase, but the majority of the metals are in a highly ionized phase exhibiting weak neutral hydrogen absorption but strong metal absorption. If such inhomogeneity is common, then high-resolution spectra and detailed ionization modeling are critical to accurately appraise the distribution of metals in the high-redshift CGM.

  15. Rhapsody-G simulations I: the cool cores, hot gas and stellar content of massive galaxy clusters

    Science.gov (United States)

    Hahn, Oliver; Martizzi, Davide; Wu, Hao-Yi; Evrard, August E.; Teyssier, Romain; Wechsler, Risa H.

    2017-01-01

    We present the RHAPSODY-G suite of cosmological hydrodynamic AMR zoom simulations of ten massive galaxy clusters at the Mvir ˜ 1015 M⊙ scale. These simulations include cooling and sub-resolution models for star formation and stellar and supermassive black hole feedback. The sample is selected to capture the whole gamut of assembly histories that produce clusters of similar final mass. We present an overview of the successes and shortcomings of such simulations in reproducing both the stellar properties of galaxies as well as properties of the hot plasma in clusters. In our simulations, a long-lived cool-core/non-cool core dichotomy arises naturally, and the emergence of non-cool cores is related to low angular momentum major mergers. Nevertheless, the cool-core clusters exhibit a low central entropy compared to observations, which cannot be alleviated by thermal AGN feedback. For cluster scaling relations we find that the simulations match well the M500 - Y500 scaling of Planck SZ clusters but deviate somewhat from the observed X-ray luminosity and temperature scaling relations in the sense of being slightly too bright and too cool at fixed mass, respectively. Stars are produced at an efficiency consistent with abundance matching constraints and central galaxies have star formation rates consistent with recent observations. While our simulations thus match various key properties remarkably well, we conclude that the shortcomings strongly suggest an important role for non-thermal processes (through feedback or otherwise) or thermal conduction in shaping the intra-cluster medium.

  16. High-temperature gas-cooled reactor safety studies. Progress report for January 1, 1974--June 30, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Cole, T.E.; Sanders, J.P.; Kasten, P.R.

    1977-07-01

    Progress is reported in the following areas: systems and safety analysis; fission product technology; primary coolant technology; seismic and vibration technology; confinement components; primary system materials technology; safety instrumentation; loss of flow accident analysis using HEATUP code; use of coupled-conduction-convection model for core thermal analysis; development of multichannel conduction-convection program HEXEREI; cooling system performance after shutdown; core auxiliary cooling system performance; development of FLODIS code; air ingress into primary systems following DBDA; performance of PCRV thermal barrier cover plates; temperature limits for fuel particle coating failure; tritium distribution and release in HTGR; energy release to PCRV during DBDA; and mathematical models for HTGR reactor safety studies.

  17. The ozonizer discharge as a gas-phase advanced oxidation process

    Energy Technology Data Exchange (ETDEWEB)

    Rosocha, L.A.

    1997-09-01

    In the past several years, there has been increased interest in gas-phase pollution control arising from a larger body of environmental regulations and a greater respect for the environment. One promising class of pollution-control technologies is that called advanced oxidation processes (AOPs). Ozonizers have been used for over a century in water treatment and for about two decades in advanced oxidation. Ozonizers are fundamentally based on non-thermal plasmas, which are useful for generating reactive species (free radicals) in gas streams. Because radical-attack reaction rate constants are very large for many chemical species, entrained pollutants are readily decomposed by these radicals. Non-thermal plasmas can generate both oxidative and reductive radicals; therefore, they show promise for treating a wide variety of pollutants. However, this application is only about a decade old, so more work is needed for optimizing and commercializing the process. This paper is intended to serve as an introduction to the subject of pollutant decomposition with the nonthermal plasmas generated by ozonizer discharges. Basic plasma and decomposition chemistry, laboratory experiments, and example applications are discussed.

  18. Using EnergyPlus to Simulate the Dynamic Response of a Residential Building to Advanced Cooling Strategies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Booten, C.; Tabares-Velasco, P. C.

    2012-08-01

    This study demonstrates the ability of EnergyPlus to accurately model complex cooling strategies in a real home with a goal of shifting energy use off peak and realizing energy savings. The house was retrofitted through the Sacramento Municipal Utility District's (SMUD) deep energy retrofit demonstration program; field tests were operated by the National Renewable Energy Laboratory (NREL). The experimental data were collected as part of a larger study and are used here to validate simulation predictions.

  19. Design and analysis of the internally cooled silicon mirrors and benders for wiggler sources at the Advanced Photon Source

    Energy Technology Data Exchange (ETDEWEB)

    Schildkamp, W.; Jaski, Y. [Consortium for Advanced Radiation Sources, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Tonnessen, T.; Douglas, G. [Rocketdyne Albuquerque Operations, 2511 C. Broadbent Parkway, N.E., Albuquerque, NM 87107 (United States)

    1996-09-01

    When silicon single crystal mirrors are bent to cylindrical figures of typically 6 km bending radius, the moments needed are very small and easy to disturb by cooling attachments to the sides of the mirror. Hence, we decided to abandon the conventional concept of cooling plates attached to the sides of the mirrors and instead have chosen to use internal water channels. We present here the design of mirrors with cooling channels near the neutral axis of the silicon beam that have a rather thick {open_quote}{open_quote}hot wall.{close_quote}{close_quote} The results of this analytical work are nonintuitive, regarding the stresses produced by wiggler heating. The design path chosen minimizes figure errors due to coolant pressure variations and residual stresses from machining and bonding of multiple layers of silicon. The geometry of the water channels avoids water-to-vacuum seals and uses the mirror bender as the coolant manifold. Engineering efforts, which reduce the bending stresses at bender-to-silicon interface by a factor of five, will be presented. The complete mirror bender and motion control mechanics will be shown. {copyright} {ital 1996 American Institute of Physics.}

  20. Effect of electricity tariffs and cooling technologies on dairy farm electricity consumption, related costs and greenhouse gas emissions

    NARCIS (Netherlands)

    Upton, J.R.; Shalloo, L.; Murphy, M.; Groot Koerkamp, P.W.G.; Boer, de I.J.M.

    2014-01-01

    The aim of this study was to provide insight into the variations in dairy farm electricity costs across five electricity tariffs. The effect of four milk cooling scenarios is also simulated to illustrate the effect of technologies on the electricity consumption, related costs and CO2 emissions of a