WorldWideScience

Sample records for high-temperature turbomachinery applications

  1. 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.

  2. Development of a HTSMA-Actuated Surge Control Rod for High-Temperature Turbomachinery Applications

    Science.gov (United States)

    Padula, Santo, II; Noebe, Ronald; Bigelow, Glen; Culley, Dennis; Stevens, Mark; Penney, Nicholas; Gaydosh, Darrell; Quackenbush, Todd; Carpenter, Bernie

    2007-01-01

    In recent years, a demand for compact, lightweight, solid-state actuation systems has emerged, driven in part by the needs of the aeronautics industry. However, most actuation systems used in turbomachinery require not only elevated temperature but high-force capability. As a result, shape memory alloy (SMA) based systems have worked their way to the forefront of a short list of viable options to meet such a technological challenge. Most of the effort centered on shape memory systems to date has involved binary NiTi alloys but the working temperatures required in many aeronautics applications dictate significantly higher transformation temperatures than the binary systems can provide. Hence, a high temperature shape memory alloy (HTSMA) based on NiTiPdPt, having a transformation temperature near 300 C, was developed. Various thermo-mechanical processing schemes were utilized to further improve the dimensional stability of the alloy and it was later extruded/drawn into wire form to be more compatible with envisioned applications. Mechanical testing on the finished wire form showed reasonable work output capability with excellent dimensional stability. Subsequently, the wire form of the alloy was incorporated into a benchtop system, which was shown to provide the necessary stroke requirements of approx.0.125 inches for the targeted surge-control application. Cycle times for the actuator were limited to 4 seconds due to control and cooling constraints but this cycle time was determined to be adequate for the surge control application targeted as the primary requirement was initial actuation of a surge control rod, which could be completed in approximately one second.

  3. Application of SPIV in turbomachinery

    Science.gov (United States)

    Liu, Baojie; Yu, Xianjun; Liu, Huoxing; Jiang, Haokang; Yuan, Huijing; Xu, Yueting

    2006-04-01

    Stereoscopic particle-image velocimetry (SPIV) has been successfully used in a low-speed large-scale axial compressor. A configuration in which two CCD cameras were placed at different sides of the light sheet was employed. It is demonstrated that the results measured with such a configuration are significant for the study of unsteady flow structures of the streamwise vortices and secondary flows in the test rotor, and that such a configuration is easy to use in multi-stage turbomachinery. The instantaneous snapshots, ensemble-averaged results and turbulence statistics in the rotor passage were obtained at both the design and near-stall conditions. The representative flow structures, such as the tip leakage vortex, the corner vortex and the inlet guide vane wake, can be depicted clearly. Moreover, according to experimental and theoretical analyses, some guidance is provided for the application of SPIV in turbomachinery.

  4. Acoustic Liner for Turbomachinery Applications

    Science.gov (United States)

    Huff, Dennis L.; Sutliff, Daniel L.; Jones, Michael G.; Hebsur, Mohan G.

    2010-01-01

    The purpose of this innovation is to reduce aircraft noise in the communities surrounding airports by significantly attenuating the noise generated by the turbomachinery, and enhancing safety by providing a containment barrier for a blade failure. Acoustic liners are used in today's turbofan engines to reduce noise. The amount of noise reduction from an acoustic liner is a function of the treatment area, the liner design, and the material properties, and limited by the constraints of the nacelle or casement design. It is desirable to increase the effective area of the acoustic treatment to increase noise suppression. Modern turbofan engines use wide-chord rotor blades, which means there is considerable treatment area available over the rotor tip. Turbofan engines require containment over the rotors for protection from blade failure. Traditional methods use a material wrap such as Kevlar integrated with rub strips and sometimes metal layers (sandwiches). It is possible to substitute the soft rub-strip material with an open-cell metallic foam that provides noise-reduction benefits and a sacrificial material in the first layer of the containment system. An open-cell foam was evaluated that behaves like a bulk acoustic liner, serves as a tip rub strip, and can be integrated with a rotor containment system. Foams can be integrated with the fan-containment system to provide sufficient safety margins and increased noise attenuation. The major innovation is the integration of the foam with the containment.

  5. Turbomachinery

    Science.gov (United States)

    Simoneau, Robert J.; Strazisar, Anthony J.; Sockol, Peter M.; Reid, Lonnie; Adamczyk, John J.

    1990-01-01

    The discipline research in turbomachinery, which is directed toward building the tools needed to understand such a complex flow phenomenon, is based on the fact that flow in turbomachinery is fundamentally unsteady or time dependent. Success in building a reliable inventory of analytic and experimental tools will depend on how we treat time and time-averages, as well as how we treat space and space-averages. The challenge is to develop a set of computational and experimental tools which genuinely increase our understanding of the fluid flow and heat transfer in a turbomachine. Examples of the types of computational and experimental tools under current development, with progress to date, are examined. The examples include work in both the time-resolved and time-averaged domains.

  6. Turbomachinery systems for floating production applications

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Jonathan P.; Kurz, Rainer [Solar Turbines Incorporated, San Diego, CA (United States)

    2008-07-01

    Since 1995 there has been a dramatic increase in oil and gas exploration and production using floating platforms in deeper waters located further offshore. This exploration started with tension leg platforms, progressed through SPARs and Semi-Submersibles, and later evolved into Floating Production Storage and Offloading (FPSO) vessels. Turbomachinery equipment installed on a floating platform or vessel will be expected to operate in the same manner as a land based machine, but in a variety of climate and environmental conditions that now includes motion. To operate successfully, specific design considerations for the turbo-machinery packages are required. It is critical to take into account the type of vessel, the expected list, trim and dynamic motion angles, the dynamic forces applied, the expected deck deflection as a result of those forces, understand the applicable class requirement, and where the equipment will be located on the vessel. This information is then translated into the design conditions to determine the type of mounting method to be used to attach the turbo-machinery package to the deck, the expected accelerations for structural analysis, and oil tank and system designs for fluid management. Furthermore, compressor designs need to allow utmost flexibility to adapt to changing operating conditions. (author)

  7. Joining SI3N4 for Advanced Turbomachinery Applications

    Energy Technology Data Exchange (ETDEWEB)

    GLASS, S. JILL; LOEHMAN, RONALD E.; HOSKING, F. MICHAEL; STEPHENS JR., JOHN J.; VIANCO, PAUL T.; NEILSEN, MICHAEL K.; WALKER, CHARLES A.; POLLINGER, J.P.; MAHONEY, F.M.; QUILLEN, B.G.

    2000-07-01

    The main objective of this project was to develop reliable, low-cost techniques for joining silicon nitride (Si{sub 3}N{sub 4}) to itself and to metals. For Si{sub 3}N{sub 4} to be widely used in advanced turbomachinery applications, joining techniques must be developed that are reliable, cost-effective, and manufacturable. This project addressed those needs by developing and testing two Si{sub 3}N{sub 4} joining systems; oxynitride glass joining materials and high temperature braze alloys. Extensive measurements were also made of the mechanical properties and oxidation resistance of the braze materials. Finite element models were used to predict the magnitudes and positions of the stresses in the ceramic regions of ceramic-to-metal joints sleeve and butt joints, similar to the geometries used for stator assemblies.

  8. Motor for High Temperature Applications

    Science.gov (United States)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  9. Application Fields of High-Temperature Superconductors

    OpenAIRE

    Hott, Roland

    2003-01-01

    Potential application fields for cuprate high-temperature superconductors (HTS) and the status of respective projects are reviewed. The availability of a reliable and inexpensive cooling technique will be essential for a future broad acceptance of HTS applications.

  10. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 k) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  11. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 K) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  12. Alloys developed for high temperature applications

    Science.gov (United States)

    Basuki, Eddy Agus; Prajitno, Djoko Hadi; Muhammad, Fadhli

    2017-01-01

    Alloys used for high temperatures applications require combinations of mechanical strength, microstructural stability and corrosion/oxidation resistance. Nickel base superalloys have been traditionally the prime materials utilized for hot section components of aircraft turbine engines. Nevertheless, due to their limited melting temperatures, alloys based on intermetallic compounds, such as TiAl base alloys, have emerged as high temperature materials and intensively developed with the main aim to replace nickel based superalloys. For applications in steam power plants operated at lower temperatures, ferritic high temperature alloys still attract high attention, and therefore, development of these alloys is in progress. This paper highlights the important metallurgical parameters of high temperature alloys and describes few efforts in the development of Fe-Ni-Al based alloys containing B2-(Fe,Ni)Al precipitates, oxide dispersion strengthening (ODS) ferritic steels and titanium aluminide based alloys include important protection system of aluminide coatings.

  13. Application of High Temperature Superconductors to Accelerators

    CERN Document Server

    Ballarino, A

    2000-01-01

    Since the discovery of high temperature superconductivity, a large effort has been made by the scientific community to investigate this field towards a possible application of the new oxide superconductors to different devices like SMES, magnetic bearings, flywheels energy storage, magnetic shielding, transmission cables, fault current limiters, etc. However, all present day large scale applications using superconductivity in accelerator technology are based on conventional materials operating at liquid helium temperatures. Poor mechanical properties, low critical current density and sensitivity to the magnetic field at high temperature are the key parameters whose improvement is essential for a large scale application of high temperature superconductors to such devices. Current leads, used for transferring currents from the power converters, working at room temperature, into the liquid helium environment, where the magnets are operating, represent an immediate application of the emerging technology of high t...

  14. Applications of bulk high-temperature superconductors

    Science.gov (United States)

    Hull, J. R.

    The development of high-temperature superconductors (HTS's) can be broadly generalized into thin-film electronics, wire applications, and bulk applications. We consider bulk HTS's to include sintered or crystallized forms that do not take the geometry of filaments or tapes, and we discuss major applications for these materials. For the most part applications may be realized with the HTS's cooled to 77 K, and the properties of the bulk HTS's are often already sufficient for commercial use. A non-exhaustive list of applications for bulk HTS's includes trapped field magnets, hysteresis motors, magnetic shielding, current leads, and magnetic bearings. These applications are briefly discussed in this paper.

  15. Aerospace applications of high temperature superconductivity

    Science.gov (United States)

    Heinen, V. O.; Connolly, D. J.

    1991-01-01

    Space application of high temperature superconducting (HTS) materials may occur before most terrestrial applications because of the passive cooling possibilities in space and because of the economic feasibility of introducing an expensive new technology which has a significant system benefit in space. NASA Lewis Research Center has an ongoing program to develop space technology capitalizing on the potential benefit of HTS materials. The applications being pursued include space communications, power and propulsion systems, and magnetic bearings. In addition, NASA Lewis is pursuing materials research to improve the performance of HTS materials for space applications.

  16. Ultra High Temperature Ceramics for aerospace applications

    OpenAIRE

    Jankowiak, A.; Justin, J.F.

    2014-01-01

    Après relecture une erreur est apparue dans le document et doit être retiré; International audience; The Ultra High Temperature Ceramics (UHTCs) are of great interest for different engineering sectors and notably the aerospace industry. Indeed, hypersonic flights, re-entry vehicles, propulsion applications and so on, require new materials that can perform in oxidizing or corrosive atmospheres at temperatures higher than 2000°C and sometimes, for long life-time. To fulfil these requirements, U...

  17. Corrosion Resistant Coatings for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Besman, T.M.; Cooley, K.M.; Haynes, J.A.; Lee, W.Y.; Vaubert, V.M.

    1998-12-01

    Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for potential application in combustion, aluminum smelting, and other harsh environments.

  18. High temperature superconductors for magnetic suspension applications

    Science.gov (United States)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  19. High temperature superconductors applications in telecommunications

    Science.gov (United States)

    Kumar, A. Anil; Li, Jiang; Zhang, Ming Fang

    1995-01-01

    The purpose of this paper is twofold: (1) to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and (2) to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices - obvious advantages versus practical difficulties - needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models - a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B) - shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance - conductivity, surface resistance and attenuation constant - will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T

  20. High temperature superconductors applications in telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.A.; Li, J.; Zhang, M.F. [Prairie View A& M Univ., Texas (United States)

    1994-12-31

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T{sub c} superconductors.

  1. High Temperature Battery for Drilling Applications

    Energy Technology Data Exchange (ETDEWEB)

    Josip Caja

    2009-12-31

    In this project rechargeable cells based on the high temperature electrochemical system Na/beta''-alumina/S(IV) in AlCl3/NaCl were developed for application as an autonomous power source in oil/gas deep drilling wells. The cells operate in the temperature range from 150 C to 250 C. A prototype DD size cell was designed and built based on the results of finite element analysis and vibration testing. The cell consisted of stainless steel case serving as anode compartment with cathode compartment installed in it and a seal closing the cell. Critical element in cell design and fabrication was hermetically sealing the cell. The seal had to be leak tight, thermally and vibration stable and compatible with electrode materials. Cathode compartment was built of beta''-alumina tube which served as an electrolyte, separator and cathode compartment.

  2. Ultrasonic Sensors for High Temperature Applications

    Science.gov (United States)

    Tittmann, Bernhard; Aslan, Mustafa

    1999-05-01

    Many processes take place under conditions other than ambient, and chief among these is high temperature. Examples of high temperature industrial processes are resin transfer molding, molten metal infiltration and rheocasting of composite metals alloys. The interaction of waves with viscous fluids is an additional complication adding to an already complicated problem of operating a sensor at high temperature for extended periods of time. This report attempts to provide an insight into the current state of the art of sensor techniques for in-situ high temperature monitoring.

  3. Balance of Plant System Analysis and Component Design of Turbo-Machinery for High Temperature Gas Reactor Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ballinger, Ronald G. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Wang, Chun Yun [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kadak, Andrew [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Todreas, Neil [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Mirick, Bradley [Concepts, Northern Engineering and Research, Woburn, MA (United States); Demetri, Eli [Concepts, Northern Engineering and Research, Woburn, MA (United States); Koronowski, Martin [Concepts, Northern Engineering and Research, Woburn, MA (United States)

    2004-08-30

    The Modular Pebble Bed Reactor system (MPBR) requires a gas turbine cycle (Brayton cycle) as the power conversion system for it to achieve economic competitiveness as a Generation IV nuclear system. The availability of controllable helium turbomachinery and compact heat exchangers are thus the critical enabling technology for the gas turbine cycle. The development of an initial reference design for an indirect helium cycle has been accomplished with the overriding constraint that this design could be built with existing technology and complies with all current codes and standards. Using the initial reference design, limiting features were identified. Finally, an optimized reference design was developed by identifying key advances in the technology that could reasonably be expected to be achieved with limited R&D. This final reference design is an indirect, intercooled and recuperated cycle consisting of a three-shaft arrangement for the turbomachinery system. A critical part of the design process involved the interaction between individual component design and overall plant performance. The helium cycle overall efficiency is significantly influenced by performance of individual components. Changes in the design of one component, a turbine for example, often required changes in other components. To allow for the optimization of the overall design with these interdependencies, a detailed steady state and transient control model was developed. The use of the steady state and transient models as a part of an iterative design process represents a key contribution of this work. A dynamic model, MPBRSim, has been developed. The model integrates the reactor core and the power conversion system simultaneously. Physical parameters such as the heat exchangers; weights and practical performance maps such as the turbine characteristics and compressor characteristics are incorporated into the model. The individual component models as well as the fully integrated model of the

  4. Potential aerospace applications of high temperature superconductors

    Science.gov (United States)

    Selim, Raouf

    1994-01-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  5. Application of Digital Particle Imaging Velocimetry to Turbomachinery

    Science.gov (United States)

    Wernet, Mark P.

    1999-01-01

    Digital Particle Imaging Velocimetry (DPIV) is a powerful measurement technique, which can be used as an alternative or complementary approach to Laser Doppler Velocimetry (LDV) in a wide range of research applications. The instantaneous planar velocity measurements obtained with PIV make it an attractive technique for use in the study of the complex flow fields encountered in turbomachinery. Many of the same issues encountered in the application of LDV to rotating machinery apply in the application of PIV. Techniques for optical access, light sheet delivery, CCD camera technology and particulate seeding are discussed. Results from the successful application of the PIV technique to both the blade passage region of a transonic axial compressor and the diffuser region of a high speed centrifugal compressor are presented. Both instantaneous and time-averaged flow fields were obtained. The 95% confidence intervals for the time-averaged velocity estimates were also determined. Results from the use of PIV to study surge in a centrifugal compressor are discussed. In addition, combined correlation/particle tracking results yielding super-resolution velocity measurements are presented.

  6. High Temperature Perforating System for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Moises E. [Schlumberger Technology Corporation, Sugar Land, TX (United States)

    2017-02-28

    The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

  7. High temperature superconductor materials and applications

    Science.gov (United States)

    Doane, George B., III. (Editor); Banks, Curtis; Golben, John

    1991-01-01

    One of the areas concerned itself with the investigation of the phenomena involved in formulating and making in the laboratory new and better superconductor material with enhanced values of critical current and temperature. Of special interest were the chemistry, physical processes, and environment required to attain these enhanced desirable characteristics. The other area concerned itself with producing high temperature superconducting thin films by pulsed laser deposition techniques. Such films are potentially very useful in the detection of very low power signals. To perform this research high vacuum is required. In the course of this effort, older vacuum chambers were maintained and used. In addition, a new facility is being brought on line. This latter activity has been replete with the usual problems of bringing a new facility into service. Some of the problems are covered in the main body of this report.

  8. High Temperature Materials for Chemical Propulsion Applications

    Science.gov (United States)

    Elam, Sandra; Hickman, Robert; O'Dell, Scott

    2007-01-01

    Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

  9. High temperature superconductors in electromagnetic applications

    CERN Document Server

    Richens, P E

    2000-01-01

    powder-in-tube and dip-coated, have been made using a novel single loop tensometer that enables the insertion of a reasonably long length of conductor into the bore of a high-field magnet. The design, construction, and characterization of a High Temperature Superconducting (HTS) magnet is described. The design stage has involved the development of computer software for the calculation of the critical current of a solenoid wound from anisotropic HTS conductor. This calculation can be performed for a variety of problems including those involving magnetic materials such as iron by the incorporation of finite element electromagnetic analysis software. This has enabled the optimization of the magnet's performance. The HTS magnet is wound from 190 m of silver-matrix Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub 1 sub 0 powder-in-tube tape conductor supplied by Intermagnetics General Corporation. The dimensions are 70 mm bore and 70 mm length, and it consists of 728 turns. Iron end-plates were utilized in order to reduc...

  10. High-temperature superconductor applications development at Argonne National Laboratory

    Science.gov (United States)

    Hull, J. R.; Poeppel, R. B.

    1992-02-01

    Developments at Argonne National Laboratory of near and intermediate term applications using high-temperature superconductors are discussed. Near-term applications of liquid-nitrogen depth sensors, current leads, and magnetic bearings are discussed in detail.

  11. Application of a Real-Fluid Turbomachinery Analysis to Rocket Turbopump Geometries

    Science.gov (United States)

    Dorney, Daniel J.; Sondak, Douglas L.; Marcu, Bogdan

    2005-01-01

    A three-dimensional flow solver has been developed for turbomachinery components utilizing real fluid properties. The code is applicable to both incompressible and compressible flow fields. In this study, the code has been applied to the analysis of inducer and impeller geometries representative of those used in rocket engine applications. The predicted results show good agreement with the available experimental data.

  12. High temperature reactors for cogeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Forschungszentrum Juelich (Germany). IEK-6; Allelein, Hans-Josef [Forschungszentrum Juelich (Germany). IEK-6; RWTH Aachen (Germany). Lehrstuhl fuer Reaktorsicherheit und -technik (LRST)

    2016-05-15

    There is a large potential for nuclear energy also in the non-electric heat market. Many industrial sectors have a high demand for process heat and steam at various levels of temperature and pressure to be provided for desalination of seawater, district heating, or chemical processes. The future generation of nuclear plants will be capable to enter the wide field of cogeneration of heat and power (CHP), to reduce waste heat and to increase efficiency. This requires an adjustment to multiple needs of the customers in terms of size and application. All Generation-IV concepts proposed are designed for coolant outlet temperatures above 500 C, which allow applications in the low and medium temperature range. A VHTR would even be able to cover the whole temperature range up to approx. 1 000 C.

  13. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  14. Using high-temperature superconductors for levitation applications

    Science.gov (United States)

    Hull, John R.

    1999-07-01

    Melt-textured, bulk high-temperature superconductors are finding increasing uses in superconducting bearings, flywheel energy storage, and other levitational applications. This article reviews the use of these materials in magnetic-levitation applications. The behavior of levitational force, stiffness, damping, and rotational losses is discussed.

  15. High-Temperature Cuprate Superconductors Experiment, Theory, and Applications

    CERN Document Server

    Plakida, Nikolay Maksimilianovich

    2010-01-01

    High-Temperature Cuprate Superconductors provides an up-to-date and comprehensive review of the properties of these fascinating materials. The essential properties of high-temperature cuprate superconductors are reviewed on the background of their theoretical interpretation. The experimental results for structural, magnetic, thermal, electric, optical and lattice properties of various cuprate superconductors are presented with respect to relevant theoretical models. A critical comparison of various theoretical models involving strong electron correlations, antiferromagnetic spin fluctuations, phonons and excitons provides a background for understanding of the mechanism of high-temperature superconductivity. Recent achievements in their applications are also reviewed. A large number of illustrations and tables gives valuable information for specialists. A text-book level presentation with formulation of a general theory of strong-coupling superconductivity will help students and researches to consolidate their...

  16. Closed-loop steerable drilling tools for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Donati, F.; Oppelt, J.; Ragnitz, D. [and others

    1995-12-31

    Today drilling environment calls for drillers to be able to access deeper, high temperature and high pressure reservoirs, where high temperature is intended close to 200{degrees}C and high pressure more than 10000 psi. A new family of automatic drilling tools has been introduced which provides automatic steering within ultra deep formations under high temperature and high pressure (HTHP) conditions. Another important use of this system is foreseen in the drilling of wells with extended reach horizontal sections. The directional changes in the Closed-Loop Drilling System are automatically generated on the basis of Measurement While Drilling (MWD) measurements taken directly within the tool. Since the major application aims at the very deep hydrocarbon layers, all components are designed to operate at temperatures between 185 to 200{degrees}C. Special consideration is given to the design of downhole motor elastomer and electronic components of the MWD. In preparation for the field application of the complete fully directional tool, field tests have been performed with a Straight Hole Drilling Closed-Loop System and other essential system components. The Straight Hole Drilling Device has been designed to drill a straight vertical well. It has been successfully run on various onshore and offshore European locations; where in one case a maximum depth of over 7,200 m was attained. Additional field case histories are provided in this report on high temperature downhole motors. The complete fully directional system will be ready for field application within end of June 1995.

  17. NASA space applications of high-temperature superconductors

    Science.gov (United States)

    Heinen, Vernon O.; Sokoloski, Martin M.; Aron, Paul R.; Bhasin, Kul B.

    1992-01-01

    The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of attaining these temperatures has been with cryogenic fluids which severely limits mission lifetime. The development of materials with superconducting transition temperatures (T sub c) above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Potential applications of high-temperature superconducting technology in cryocoolers and remote sensing, communications, and power systems are discussed.

  18. NASA Space applications of high-temperature superconductors

    Science.gov (United States)

    Heinen, Vernon O.; Sokoloski, Martin M.; Aron, Paul R.; Bhasin, Kul B.; Wintucky, Edwin G.; Connolly, Denis J.

    1992-01-01

    The application of superconducting technology in space has been limited by the requirement of cooling to near liquid helium temperatures. The only means of obtaining these temperatures has been with cryogenic fluids which severely limit mission lifetime. The development of materials with superconducting transition temperatures above 77 K has made superconducting technology more attractive and feasible for employment in aerospace systems. Here, potential applications of high temperature superconducting technology in cryocoolers, remote sensing, communications, and power systems are discussed.

  19. Cryocooler applications for high-temperature superconductor magnetic bearings.

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, R. C.

    1998-05-22

    The efficiency and stability of rotational magnetic suspension systems are enhanced by the use of high-temperature superconductor (HTS) magnetic bearings. Fundamental aspects of the HTS magnetic bearings and rotational magnetic suspension are presented. HTS cooling can be by liquid cryogen bath immersion or by direct conduction, and thus there are various applications and integration issues for cryocoolers. Among the numerous cryocooler aspects to be considered are installation; operating temperature; losses; and vacuum pumping.

  20. 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.

  1. High-Temperature Piezoelectric Crystals for Acoustic Wave Sensor Applications.

    Science.gov (United States)

    Zu, Hongfei; Wu, Huiyan; Wang, Qing-Ming

    2016-03-01

    In this review paper, nine different types of high-temperature piezoelectric crystals and their sensor applications are overviewed. The important materials' properties of these piezoelectric crystals including dielectric constant, elastic coefficients, piezoelectric coefficients, electromechanical coupling coefficients, and mechanical quality factor are discussed in detail. The determination methods of these physical properties are also presented. Moreover, the growth methods, structures, and properties of these piezoelectric crystals are summarized and compared. Of particular interest are langasite and oxyborate crystals, which exhibit no phase transitions prior to their melting points ∼ 1500 °C and possess high electrical resistivity, piezoelectric coefficients, and mechanical quality factor at ultrahigh temperature ( ∼ 1000 °C). Finally, some research results on surface acoustic wave (SAW) and bulk acoustic wave (BAW) sensors developed using this high-temperature piezoelectric crystals are discussed.

  2. Status and future perspective of applications of high temperature superconductors

    Science.gov (United States)

    Tanaka, Shoji

    The material research on the high temperature superconductivity for the past ten years gave us sufficient information on the new phenomena of these new materials. It seems that new applications in a very wide range of industries are increasing rapidly. In this report three main topics of the applications are given ; [a] progress of the superconducting bulk materials and their applications to the flywheel electricity storage system and others, [b] progress in the development of superconducting tapes and their applications to power cables, the high field superconducting magnet for the SMES and for the pulling system of large silicon single crystal, and [c] development of new superconducting electronic devices (SFQ) and the possiblity of the application to next generation supercomputers. These examples show the great capability of the superconductivity technology and it is expected that the real superconductivity industry will take off around the year of 2005.

  3. Protective coatings for very high temperature reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Cabet, C.; Guerre, C. [Service de la Corrosion et du Comportement des Materiaux dans leur Environnement, DEN/DANS/DPC, CEA Saclay, 91191 Gif sur Yvette (France); Thieblemont, F. [Optoelectronics Materials Laboratory, Materials and Interfaces Department, Weizmann Institute of Science, Rehovot (Israel)

    2008-07-15

    The future very high temperature reactors (VHTR) are nuclear systems that shall operate at a maximum temperature of about 950 C. Primary circuit materials thus require good creep and corrosion resistance on very long time. Use of high-strength alloys with protective coatings could significantly improve the service life of high temperature reactor components. However, coating systems are mainly designed for shorter term purposes, often under extremely aggressive atmospheres, that cannot be extrapolated to the VHTR environment. We present our first investigations on the environmental resistance of Alloy 800H coated with two different protective systems under VHTR representative conditions: NiAl(Pt)/EBPVD ZrO{sub 2}(Y) and NiCrAl(Y)/CVD ZrO{sub 2}(Y). Isothermal exposures were carried out up to 1000 h at 950 C in impure helium. This specific atmosphere was shown to induce formation of a surface oxide scale together with carburisation of the bare Alloy 800H. After high temperature exposure to impure helium, the microstructure of the coated specimens has changed due to both thermal ageing and corrosion. Performances of the two coating systems are compared regarding the VHTR application. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  4. Advanced Capacitor with SiC for High Temperature Applications

    Science.gov (United States)

    Tsao, B. H.; Ramalingam, M. L.; Bhattacharya, R. S.; Carr, Sandra Fries

    1994-07-01

    An advanced capacitor using SiC as the dielectric material has been developed for high temperature, high power, and high density electronic components for aircraft and aerospace application. The conventional capacitor consists of a large number of metallized polysulfone films that are arranged in parallel and enclosed in a sealed metal case. However, problems with electrical failure, thermal failure, and dielectric flow were experienced by Air Force suppliers for the component and subsystem for lack of suitable properties of the dielectric material. The high breakdown electrical field, high thermal conductivity, and high temperature operational resistance of SiC compared to similar properties of the conventional ceramic and polymer capacitor would make it a better choice for a high temperature, and high power capacitor. The quality of the SiC film was evaluated. The electrical parameters, such as the capacitance, dissipation factor, equivalent series resistance, and dielectric withstand voltage, were evaluated. The prototypical capacitors are currently being fabricated using SiC film.

  5. Ultra light weight refractory material for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Finke, V.; Kern, H. [Rath GmbH, Meissen (Germany); Springer, M. [Aug. Rath jun. GmbH, Vienna (Austria)

    2007-07-01

    The requirements on companies running high temperature processes, i.e. at temperatures about 1000 C and above, have increased dramatically within the last few years. For technological, economical and ecological purposes each application has to be checked carefully. As well the political discussion regarding environmental pollution, greenhouse effect and emission trading and the guidelines for climate and environmental protection exert massive influence on thermal process technology and pose an appropriate challenge for the companies. Next to costs of labour and raw materials the costs for energy and environmental costs play a decisive role more and more. The pressure on the management thereby incurred may have a lasting effect on innovations regarding increase of energy efficiency, decrease of CO{sub 2}-emission and often on non negligible increase of productivity. Mainly against the background of the highly scheduled European aims for emission reduction and also in consideration of the still proceeding globalisation the usage of state-of-the-art refractory technics in thermal process technology is of particular importance for business success, for reducing of environmental impact and last but not least for conservation and safeguarding of jobs in Europe and Germany. The applications for products made from high-temperature insulation wool in high temperature applications have strongly increased during the last five years. Especially the production capacities of polycrystalline wool (aluminium oxide wool e.g. Altra B72) have been doubled within the last three years. Primarily ultra light weight products made from HTIW are used in industrial furnaces with application temperatures above 1000 C and / or with high thermo-mechanical (thermal shock) and chemical exposure. The outstanding and essential advantages of these materials are obviously: Ultra light weight material with high resilience and flexibility, Optimised energy consumption (energy saving up to 50% compared

  6. Applications of Silicon Carbide for High Temperature Electronics and Sensors

    Science.gov (United States)

    Shields, Virgil B.

    1995-01-01

    Silicon carbide (SiC) is a wide bandgap material that shows great promise in high-power and high temperature electronics applications because of its high thermal conductivity and high breakdown electrical field. The excellent physical and electronic properties of SiC allows the fabrication of devices that can operate at higher temperatures and power levels than devices produced from either silicon or GaAs. Although modern electronics depends primarily upon silicon based devices, this material is not capable of handling may special requirements. Devices which operate at high speeds, at high power levels and are to be used in extreme environments at high temperatures and high radiation levels need other materials with wider bandgaps than that of silicon. Many space and terrestrial applications also have a requirement for wide bandgap materials. SiC also has great potential for high power and frequency operation due to a high saturated drift velocity. The wide bandgap allows for unique optoelectronic applications, that include blue light emitting diodes and ultraviolet photodetectors. New areas involving gas sensing and telecommunications offer significant promise. Overall, the properties of SiC make it one of the best prospects for extending the capabilities and operational regimes of the current semiconductor device technology.

  7. Emerging applications of high temperature superconductors for space communications

    Science.gov (United States)

    Heinen, Vernon O.; Bhasin, Kul B.; Long, Kenwyn J.

    1990-01-01

    Proposed space missions require longevity of communications system components, high input power levels, and high speed digital logic devices. The complexity of these missions calls for a high data bandwidth capacity. Incorporation of high temperature superconducting (HTS) thin films into some of these communications system components may provide a means of meeting these requirements. Space applications of superconducting technology has previously been limited by the requirement of cooling to near liquid helium temperatures. Development of HTS materials with transition temperatures above 77 K along with the natural cooling ability of space suggest that space applications may lead the way in the applications of high temperature superconductivity. In order for HTS materials to be incorporated into microwave and millimeter wave devices, the material properties such as electrical conductivity, current density, surface resistivity and others as a function of temperature and frequency must be well characterized and understood. The millimeter wave conductivity and surface resistivity were well characterized, and at 77 K are better than copper. Basic microwave circuits such as ring resonators were used to determine transmission line losses. Higher Q values than those of gold resonator circuits were observed below the transition temperature. Several key HTS circuits including filters, oscillators, phase shifters and phased array antenna feeds are feasible in the near future. For technology to improve further, good quality, large area films must be reproducibly grown on low dielectric constant, low loss microwave substrates.

  8. Applications of high-temperature superconductors in power technology

    Science.gov (United States)

    Hull, John R.

    2003-11-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications.

  9. Oxidation of Palladium-Chromium Alloys for High Temperature Applications

    Science.gov (United States)

    Piltch, Nancy D.; Jih-Fen, Lei; Zeller, Mary V.

    1994-01-01

    An alloy consisting of Pd with 13 wt % Cr is a promising material for high temperature applications. High temperature performance is degraded by the oxidation of the material, which is more severe in the fine wires and thin films used for sensor applications than in the bulk. The present study was undertaken to improve our understanding of the physical and chemical changes occurring at these temperatures and to identify approaches to limit oxidation of the alloy. The alloy was studied in both ribbon and wire forms. Ribbon samples were chosen to examine the role of grain boundaries in the oxidation process because of the convenience of handling for the oxidation studies. Wire samples 25 microns in diameter which are used in resistance strain gages were studied to correlate chemical properties with observed electrical, physical, and structural properties. Overcoating the material with a metallic Cr film did prevent the segregation of Pd to the surface; however, it did not eliminate the oxidation of the alloy.

  10. Some potential antenna applications of high-temperature superconductors

    Science.gov (United States)

    Dinger, Robert J.

    1990-09-01

    A review of possible applications of high temperature superconductors (HTS) to antennas and antenna feed networks is presented. The frequency range of consideration is 1 MHz to 100 GHz. Three antenna application areas seem appropriate for HTS material. (1) Electrically small antennas and their matching networks: an increase in efficiency is possible for electrically short antennas, but at the expense of bandwidth. Substantial radiated power levels (on the order of kilowatts) can be handled by the best HTS material. Substantial improvement may be realized by making only the matching network of HTS material. (2) Feed and matching networks for compact arrays with enhanced directive gain (superdirective arrays): HTS material should permit such arrays to be fabricated that have high efficiency. (3) Feed networks for millimeter-wave arrays: Low-loss feed networks using HTS microstrip transmission lines give many decibels improvement in gain.

  11. Assessment of microelectronics packaging for high temperature, high reliability applications

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, F.

    1997-04-01

    This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

  12. High temperature material developments in fossil energy applications

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B. (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center)

    1992-04-01

    Two major application areas of fossil energy are: - petrochemical processing, - electrical power production. In both of them, there are important common features in the field high temperature, though there are different controlling factors. Furthermore, since they are both concerned with the combustion of carbonaceous fuels, questions of emissions are relevant to both. However, the trend in petrochemical plants has been to use a refined fuel to heat the chemical reactors and this reduces both gaseous and particulate emissions. A major driving force in both areas has always been the attainment of higher efficiencies which implies the use of higher process temperatures. This normally involves higher temperatures for the constructional material. Ideally, the increased temperature capability should be achieved without loss of strength, corrosion resistance, feasibility or reliability. Furthermore, the relative cost of the finished component should not be increased. Clearly, this ideal is seldom attained and an optimization between the competing factors has to be made. 16 refs., 15 figs.

  13. High-Temperature Strain Sensing for Aerospace Applications

    Science.gov (United States)

    Piazza, Anthony; Richards, Lance W.; Hudson, Larry D.

    2008-01-01

    Thermal protection systems (TPS) and hot structures are utilizing advanced materials that operate at temperatures that exceed abilities to measure structural performance. Robust strain sensors that operate accurately and reliably beyond 1800 F are needed but do not exist. These shortcomings hinder the ability to validate analysis and modeling techniques and hinders the ability to optimize structural designs. This presentation examines high-temperature strain sensing for aerospace applications and, more specifically, seeks to provide strain data for validating finite element models and thermal-structural analyses. Efforts have been made to develop sensor attachment techniques for relevant structural materials at the small test specimen level and to perform laboratory tests to characterize sensor and generate corrections to apply to indicated strains. Areas highlighted in this presentation include sensors, sensor attachment techniques, laboratory evaluation/characterization of strain measurement, and sensor use in large-scale structures.

  14. Progress on applications of high temperature superconducting microwave filters

    Science.gov (United States)

    Chunguang, Li; Xu, Wang; Jia, Wang; Liang, Sun; Yusheng, He

    2017-07-01

    In the past two decades, various kinds of high performance high temperature superconducting (HTS) filters have been constructed and the HTS filters and their front-end subsystems have been successfully applied in many fields. The HTS filters with small insertion loss, narrow bandwidth, flat in-band group delay, deep out-of-band rejection, and steep skirt slope are reviewed. Novel HTS filter design technologies, including those in high power handling filters, multiband filters and frequency tunable filters, are reviewed, as well as the all-HTS integrated front-end receivers. The successful applications to various civilian fields, such as mobile communication, radar, deep space detection, and satellite technology, are also reviewed.

  15. High temperature solder alloys for underhood applications. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Labs., Albuquerque, NM (United States); Kern, J.; Weiser, M.W. [Univ. of New Mexico (United States). Dept. of Mechanical Engineering

    1995-02-01

    Under a cooperative research and development agreement with General Motors Corporation, lead-free solder systems including the flux, metallization, and solder are being developed for high temperature, underhood applications. Six tin-rich solders, five silver-rich metallizations, and four fluxes were screened using an experimental matrix whereby every combination was used to make sessile drops via hot plate or Heller oven processing. The contact angle, sessile drop appearance, and in some instances the microstructure was evaluated to determine combinations that would yield contact angles of less than 30{degrees}, well-formed sessile drops, and fine, uniform microstructures. Four solders, one metallization, and one flux were selected and will be used for further aging and mechanical property studies.

  16. High temperature three-dimensional photoplasticity: Procedures and application

    Science.gov (United States)

    Song, Baoyun; He, Youliang; Bai, Guangrun

    1998-05-01

    Polycarbonate, because of its extreme toughness, pronounced yield behavior, and the ability to flow extensively prior to fracture, is suitable material for photoplastic analysis and is widely used in recent years. In most cases where the deformations are small, photoplastic experiments are usually conducted at room temperature. But in some applications where the model materials are due to undergo large deformations, to avoid too early occurrence of brittleness, the models should be heated to a higher temperature to improve their deformabilities. This paper investigates the possibility of the utility of high temperature photoplasticity to the simulation of complicated metal forming processes and gives the approprate test temperature of polycarbonate as a photoplastic material. As an example, the three-dimensional strain distributions in the die chamber of continuous cladding process are evaluated.

  17. Applicability Assessment on LBB Application in High Temperature Sodium Piping

    Institute of Scientific and Technical Information of China (English)

    WANG; Yue-ying; LIU; Jia

    2015-01-01

    LBB has been an important technology for ensuring security and stability of reactor structure after 30years of application and development,and is applied widely in PWR.Primary research on LBB application in sodium piping has been done after China first fast reactor—CEFR

  18. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-12-31

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  19. Development of high temperature superconductors for magnetic field applications

    Energy Technology Data Exchange (ETDEWEB)

    Larbalestier, D.C.

    1991-01-01

    The key requirement for magnetic field applications of high temperature superconductor (HTS) materials is to have conductors with high transport critical current density available for magnet builders. After 3 or 4 years of being without any such object, conductor makers have had recent success in producing simple conductor prototypes. These have permitted the construction of simple HTS magnets having self fields exceeding 1 tesla at 4K. Thus the scientific feasibility of making powerful HTS magnets has been demonstrated. Attention to the technological aspects of making HTS conductors for magnets with strong flux pinning and reduced superconducting granularity is now sensible and attractive. However, extrinsic defects such as filament sausaging, cracking, misaligned grains and other perturbation to long range current flow must be controlled at a low level if the benefit of intrinsic improvements to the critical current density is to be maintained in the conductor form. Due to the great complexity of the HTS materials, there is sometimes confusion as to whether a given sample has an intrinsically or extrinsically limited critical current density. Systematic microstructure variation experiments and resistive transition analysis are shown to be particularly helpful in this phase of conductor development.

  20. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future space science missions cannot be realized without the state of the art high temperature insulation materials of which higher working temperature, high...

  1. High Temperature Gas Reactors: Assessment of Applicable Codes and Standards

    Energy Technology Data Exchange (ETDEWEB)

    McDowell, Bruce K.; Nickolaus, James R.; Mitchell, Mark R.; Swearingen, Gary L.; Pugh, Ray

    2011-10-31

    Current interest expressed by industry in HTGR plants, particularly modular plants with power up to about 600 MW(e) per unit, has prompted NRC to task PNNL with assessing the currently available literature related to codes and standards applicable to HTGR plants, the operating history of past and present HTGR plants, and with evaluating the proposed designs of RPV and associated piping for future plants. Considering these topics in the order they are arranged in the text, first the operational histories of five shut-down and two currently operating HTGR plants are reviewed, leading the authors to conclude that while small, simple prototype HTGR plants operated reliably, some of the larger plants, particularly Fort St. Vrain, had poor availability. Safety and radiological performance of these plants has been considerably better than LWR plants. Petroleum processing plants provide some applicable experience with materials similar to those proposed for HTGR piping and vessels. At least one currently operating plant - HTR-10 - has performed and documented a leak before break analysis that appears to be applicable to proposed future US HTGR designs. Current codes and standards cover some HTGR materials, but not all materials are covered to the high temperatures envisioned for HTGR use. Codes and standards, particularly ASME Codes, are under development for proposed future US HTGR designs. A 'roadmap' document has been prepared for ASME Code development; a new subsection to section III of the ASME Code, ASME BPVC III-5, is scheduled to be published in October 2011. The question of terminology for the cross-duct structure between the RPV and power conversion vessel is discussed, considering the differences in regulatory requirements that apply depending on whether this structure is designated as a 'vessel' or as a 'pipe'. We conclude that designing this component as a 'pipe' is the more appropriate choice, but that the ASME BPVC

  2. Stability of Materials in High Temperature Water Vapor: SOFC Applications

    Science.gov (United States)

    Opila, E. J.; Jacobson, N. S.

    2010-01-01

    Solid oxide fuel cell material systems require long term stability in environments containing high-temperature water vapor. Many materials in fuel cell systems react with high-temperature water vapor to form volatile hydroxides which can degrade cell performance. In this paper, experimental methods to characterize these volatility reactions including the transpiration technique, thermogravimetric analysis, and high pressure mass spectrometry are reviewed. Experimentally determined data for chromia, silica, and alumina volatility are presented. In addition, data from the literature for the stability of other materials important in fuel cell systems are reviewed. Finally, methods for predicting material recession due to volatilization reactions are described.

  3. High temperature solar furnace: current applications and future potential

    Energy Technology Data Exchange (ETDEWEB)

    Bjorndalen, N. [Dalhousie Univ., Faculty of Engineering, Halifax, NS (Canada)

    2003-02-15

    The high temperature solar furnace can offer great opportunities for the production of many types of products worldwide, but recent advances in this technology have been limited to metal reduction. The production of semiconductors, which are utilized to a great extent in the electronic industry, is a viable option for this technology that has been overlooked. Especially where sand and sunlight are plentiful (countries that surround the equator), silicon chips produced with a solar furnace can have great economical value. This paper describes current and potential solar furnace technologies. The components of the solar furnace are described, as well as metal reduction processes including zinc and aluminum production. The viability of silicon chip production is also examined. The possibilities for other product development using an extremely (up to 10,000 deg C) high temperature solar furnace are also discussed. Economically, the benefits of solar furnaces are great, with only high initial start-up costs and little operation costs. Metal reduction processes can also be enhanced with high temperature solar furnaces in that plugging problems are eliminated. By replacing conventional furnaces, such as blast and electric arc furnaces, with a high temperature solar furnace, CO{sub 2} emissions and energy consumption can be greatly reduced, which will bring in added dividends to the society. (Author)

  4. Mechanical Properties of Ceramics for High Temperature Applications

    Science.gov (United States)

    1976-12-01

    deeply indebted to the authors for their efforts in preparing and presenting these papers. Norman M.TALLAN Chairman High Temperature Materials Sub...methods (&.g. starting powder, powder preparation , forming procedure, reaction sintering shedule, atmospheres used), impurities, porosity, pore size...exposure. The contribution of the cristobalite together with the glass phase to the grain boundary viscosity has not been investigated. One can

  5. NOVEL GAS SENSORS FOR HIGH-TEMPERATURE FOSSIL FUEL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Palitha Jayaweera

    2004-05-01

    SRI is developing ceramic-based microsensors for detection of exhaust gases such as NO, NO{sub 2}, and CO in advanced combustion and gasification systems. The sensors detect the electrochemical activity of the exhaust gas species on catalytic electrodes and are designed to operate at high temperatures, elevated pressures, and corrosive environments typical of large power generation exhausts. Under this research project we are developing sensors for multiple gas detection in a single package along with data acquisition and control software and hardware. The sensor package can be easily integrated into online monitoring systems for active emission control. This report details the research activities performed from October 2003 to April 2004.

  6. Ultrasonic/Sonic Drill for High Temperature Application

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Scott, James; Sherrit, Stewart; Widholm, Scott; Badescu, Mircea; Shrout, Tom; Jones, Beth

    2010-01-01

    Venus is one of the many significant scientific targets for NASA. New rock sampling tools with the ability to be operated at high temperatures of the order of 460 deg C are required for surface in-situ sampling/analysis missions. Piezoelectric materials such as LiNbO? crystals and Bismuth Titanate are potentially operational at the temperature range found on the surface of Venus. A study of the feasibility of producing piezoelectric drills for a temperature up to 500 deg C was conducted. The study includes investigation of the high temperature properties of piezoelectric crystals and ceramics with different formulas and doping. Several prototypes of Ultrasonic/Sonic Drill/Corers (USDC) driven by transducers using the high temperate piezoelectric ceramics and single LiNbO? crystal were fabricated. The transducers were analyzed by scanning the impedance at room temperature and 500 deg C under both low and high voltages. The drilling performances were tested at temperature up to 500 deg C. Preliminary results were previously reported [Bao et al, 2009]. In this paper, the progress is presented and the future works for performance improvements are discussed.

  7. Ultrasonic/Sonic Drill for High Temperature Application

    Science.gov (United States)

    Bao, Xiaoqi; Bar-Cohen, Yoseph; Scott, James; Sherrit, Stewart; Widholm, Scott; Badescu, Mircea; Shrout, Tom; Jones, Beth

    2010-01-01

    Venus is one of the many significant scientific targets for NASA. New rock sampling tools with the ability to be operated at high temperatures of the order of 460 deg C are required for surface in-situ sampling/analysis missions. Piezoelectric materials such as LiNbO? crystals and Bismuth Titanate are potentially operational at the temperature range found on the surface of Venus. A study of the feasibility of producing piezoelectric drills for a temperature up to 500 deg C was conducted. The study includes investigation of the high temperature properties of piezoelectric crystals and ceramics with different formulas and doping. Several prototypes of Ultrasonic/Sonic Drill/Corers (USDC) driven by transducers using the high temperate piezoelectric ceramics and single LiNbO? crystal were fabricated. The transducers were analyzed by scanning the impedance at room temperature and 500 deg C under both low and high voltages. The drilling performances were tested at temperature up to 500 deg C. Preliminary results were previously reported [Bao et al, 2009]. In this paper, the progress is presented and the future works for performance improvements are discussed.

  8. A THERMODYNAMIC CAVITATION MODEL APPLICABLE TO HIGH TEMPERATURE FLOW

    Directory of Open Access Journals (Sweden)

    De-Min Liu

    2011-01-01

    Full Text Available Cavitation is not only related with pressure, but also affected by temperature. Under high temperature, temperature depression of liquids is caused by latent heat of vaporization. The cavitation characteristics under such condition are different from those under room temperature. The paper focuses on thermodynamic cavitation based on the Rayleigh-Plesset equation and modifies the mass transfer equation with fully consideration of the thermodynamic effects and physical properties. To validate the modified model, the external and internal flow fields, such as hydrofoil NACA0015 and nozzle, are calculated, respectively. The hydrofoil NACA0015's cavitation characteristic is calculated by the modified model at different temperatures. The pressure coefficient is found in accordance with the experimental data. The nozzle cavitation under the thermodynamic condition is calculated and compared with the experiment.

  9. NOVEL GAS SENSORS FOR HIGH-TEMPERATURE FOSSIL FUEL APPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Palitha Jayaweera

    2004-05-01

    SRI is developing ceramic-based microsensors for detection of exhaust gases such as NO, NO{sub 2}, and CO in advanced combustion and gasification systems. The sensors detect the electrochemical activity of the exhaust gas species on catalytic electrodes and are designed to operate at high temperatures, elevated pressures, and corrosive environments typical of large power generation exhausts. Under this research project we are developing sensors for multiple gas detection in a single package along with data acquisition and control software and hardware. The sensor package can be easily integrated into online monitoring systems for active emission control. This report details the research activities performed from May 2004 to October 2004 including testing of catalytic materials, sensor design and fabrication, and software development.

  10. High temperature fatigue of metal matrix composite for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Marie-Louise, A.; Koster, A.; Remy, L. [Centre des Materiaux, PM. Fourt, Ecole Nationale Superieure des Mines de Paris, UMR CNRS 763, Evry (France); Bourgeois, M.; Martin-Borret, S. [PSA, Peugeot Citroeen, Direction de la Recherche et de l' Innovation Automobile, Velizy-Villacoublay (France)

    2004-07-01

    The high temperature low cycle fatigue (LCF) of metal-matrix composite (A356 with alumina reinforcement) was investigated. LCF tests interrupted and conducted up to failure were performed. Firstly, the effect of process defects and volume fraction of alumina was investigated for this composite. Then, damage accumulation was reported: an interrupted test procedure was used with a plastic replication technique. According to crack growth, the end of the LCF test is associated with a critical crack length equal to about 2 mm. Furthermore, an original crack growth LCF test was made using a specimen with three through notches at different locations. The effect of notch location was estimated. TOMKINS' model has finally been modified to predict the LCF crack growth and the life of smooth specimens. (orig.)

  11. 9 Cr-- 1 Mo steel material for high temperature application

    Science.gov (United States)

    Jablonski, Paul D; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-11-27

    One or more embodiments relates to a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The 9 Cr-1 Mo steel has a tempered martensite microstructure and is comprised of both large (0.5-3 .mu.m) primary titanium carbides and small (5-50 nm) secondary titanium carbides in a ratio of. from about 1:1.5 to about 1.5:1. The 9 Cr-1 Mo steel may be fabricated using exemplary austenizing, rapid cooling, and tempering steps without subsequent hot working requirements. The 9 Cr-1 Mo steel exhibits improvements in total mass gain, yield strength, and time-to-rupture over ASTM P91 and ASTM P92 at the temperature and time conditions examined.

  12. Novel Gas Sensors for High-Temperature Fossil Fuel Applications

    Energy Technology Data Exchange (ETDEWEB)

    Palitha Jayaweera; Francis Tanzella

    2005-03-01

    SRI International (SRI) is developing ceramic-based microsensors to detect exhaust gases such as NO, NO{sub 2}, and CO in advanced combustion and gasification systems under this DOE NETL-sponsored research project. The sensors detect the electrochemical activity of the exhaust gas species on catalytic electrodes attached to a solid state electrolyte and are designed to operate at the high temperatures, elevated pressures, and corrosive environments typical of large power generation exhausts. The sensors can be easily integrated into online monitoring systems for active emission control. The ultimate objective is to develop sensors for multiple gas detection in a single package, along with data acquisition and control software and hardware, so that the information can be used for closed-loop control in novel advanced power generation systems. This report details the Phase I Proof-of-Concept, research activities performed from October 2003 to March 2005. SRI's research work includes synthesis of catalytic materials, sensor design and fabrication, software development, and demonstration of pulse voltammetric analysis of NO, NO{sub 2}, and CO gases on catalytic electrodes.

  13. Ultra high temperature ceramics for hypersonic vehicle applications.

    Energy Technology Data Exchange (ETDEWEB)

    Tandon, Rajan; Dumm, Hans Peter; Corral, Erica L.; Loehman, Ronald E.; Kotula, Paul Gabriel

    2006-01-01

    HfB{sub 2} and ZrB{sub 2} are of interest for thermal protection materials because of favorable thermal stability, mechanical properties, and oxidation resistance. We have made dense diboride ceramics with 2 to 20 % SiC by hot pressing at 2000 C and 5000 psi. High-resolution transmission electron microscopy (TEM) shows very thin grain boundary phases that suggest liquid phase sintering. Fracture toughness measurements give RT values of 4 to 6 MPam{sup 1/2}. Four-pt flexure strengths measured in air up to 1450 C were as high as 450-500 MPa. Thermal diffusivities were measured to 2000 C for ZrB{sub 2} and HfB{sub 2} ceramics with SiC contents from 2 to 20%. Thermal conductivities were calculated from thermal diffusivities and measured heat capacities. Thermal diffusivities were modeled using different two-phase composite models. These materials exhibit excellent high temperature properties and are attractive for further development for thermal protection systems.

  14. Polymer-matrix Composites for High-temperature Applications

    Directory of Open Access Journals (Sweden)

    P.D. Mangalgiri

    2005-04-01

    Full Text Available Over the last decade, applications of fibre-reinforced composites using polymer matrices have seen tremendous growth. In spite of the complexity of their behaviour and the unconventionalnature of fabrication and other aspects, the usage of such composites, even for primary loadbearing structures in military fighters and transport aircraft, and satellites and space vehicles has been beneficially realised. Most of such usage constituted structural applications (such as in airframe where service temperatures are not expected to he beyond 120 'C. Attention is now focussed on expanding the usage of such composites to other areas where temperatures could be higher-in the range 200400 "C. The intended applications are structural and non-structural parts on or around the aero-engines and airframe components for supersonic or hypersonic aircraft. The development of polymer matrices-such as bismaleimides, polyimides, cyanates, and liquid crystalline polymers and others-has brought such applications within the realm of practicability. The associated problems have been in terms of suitable processing technologies and in balancing the requirements of the performance with those of the processing. This paper describes briefly such developments and reviews the potential application scenario.

  15. Development of lead-free solders for high-temperature applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek

    -temperature applications. Unfortunately, even the substitute technologies that are currently being developed cannot address several critical issues of high-temperature soldering. Therefore, further research and development of high-temperature lead-free soldering is obviously needed. It is hoped that this thesis can serve...... as a valuable source of information to those interested in environmentally conscious electronic packaging....

  16. Potential power sources for high-temperature geothermal applications

    Energy Technology Data Exchange (ETDEWEB)

    Guidotti, R.A.; Dobranich, D

    1996-05-01

    The thermal response under geothermal-borehole conditions of a conventional thermal battery was evaluated for various designs by numerical simulations using a finite-element thermal model. This technology, which is based on molten salts, may be suitable as a power source for geothermal borehole applications for data logging. Several promising candidate electrolytes were identified for further study.

  17. Advanced Ceramic Matrix Composites (CMCs) for High Temperature Applications

    Science.gov (United States)

    Singh, M.

    2005-01-01

    Advanced ceramic matrix composites (CMCs) are enabling materials for a number of demanding applications in aerospace, energy, and nuclear industries. In the aerospace systems, these materials are being considered for applications in hot sections of jet engines such as the combustor liner, vanes, nozzle components, nose cones, leading edges of reentry vehicles, and space propulsion components. Applications in the energy and environmental industries include radiant heater tubes, heat exchangers, heat recuperators, gas and diesel particulate filters, and components for land based turbines for power generation. These materials are also being considered for use in the first wall and blanket components of fusion reactors. In the last few years, a number of CMC components have been developed and successfully tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. They include robust fabrication and manufacturing, assembly and integration, coatings, property modeling and life prediction, design codes and databases, repair and refurbishment, and cost. Fabrication of net and complex shape components with high density and tailorable matrix properties is quite expensive, and even then various desirable properties are not achievable. In this presentation, a number of examples of successful CMC component development and testing will be provided. In addition, critical need for robust manufacturing, joining and assembly technologies in successful implementation of these systems will be discussed.

  18. Conduction cooled high temperature superconducting dipole magnet for accelerator applications

    DEFF Research Database (Denmark)

    Zangenberg, N.; Nielsen, G.; Hauge, N.

    2012-01-01

    impregnated with epoxy and mounted between a support of stainless steel and a collar made from aluminum. The cold mass consisting of the coil assembly and a laminated steel yoke is cooled by two cryocoolers from via copper bars to below 20 K. Current leads were made from the same batch of HTS tape. Cryogen...... for accelerator applications in many fields, in particular where cryogenic liquid cooling is not an option....

  19. Ceramic high temperature superconductors for high current applications

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, J.

    1996-12-31

    Composite Reaction Texturing (CRT) is a technique which uses a fine distribution of pre-aligned seeds as nucleating sites for texturing oxide superconductors. It has successfully been applied to the texturing of Bi-2212 compounds. A furhter application of CRT is reported in which Y-123 is biaxially textured using seeds of other Rare Earth-123 compounds with higher melting points as nucleating sites. The resultant textured microstructure exhibits mainly low angle grain boundaries (up to 5 deg. misorientation). Results will be presented on the seed alignment techniques, the development of microstructure during reaction of the composite preform and preliminary measurements of electromagnetic properties. (au). 111 refs.

  20. Development and application of nonflammable, high-temperature beta fibers

    Science.gov (United States)

    Dawn, Frederic S.

    1989-01-01

    Recent advances in fiber technology have contributed to the success of the U.S. space program. The inorganic fiber Beta, developed as a result of efforts begun in the early 1960's and heightened following the January 27, 1967 Apollo fire is unique among inorganic and organic fibers. It has been developed into woven, nonwoven, knitted, braided, coated and printed structures. All of these were used extensively for the Apollo, Skylab, Apollo-Soyuz test project, space shuttle, Spacelab, and satellite programs. In addition to being used successfully in the space program, Beta fibers are being used commercially as firesafe fabrics in homes, hospitals, institutions, public buildings, aircraft, and public transportation, wherever total nonflammability is required. One of the most unique applications of the Beta composite structure is the roofing material for the 80,000-seat Detroit Lion's Silverdome and 5 square miles of the Jeddah International Airport in Saudi Arabia. This fiber has been successfully incorporated into 165 major public construction projects around the globe. The United States alone has used more than 12 million square yards of the material. Beta fiber has been used successfully to date and has a promising future with unlimited potential for both space and commercial application. Efforts are currently underway to improve Beta fiber to meet the requirements of extended service life for the Space Station Freedom, lunar outpost, and Mars exploration missions.

  1. The Application of High Temperature Superconducting Materials to Power Switches

    CERN Document Server

    March, S A; Ballarino, A

    2009-01-01

    Superconducting switches may find application in superconducting magnet systems that require energy extraction. Such superconducting switches could be bypass-switches that are operated in conjunction with a parallel resistor or dump-switches where all of the energy is dissipated in the switch itself. Bypass-switches are more suited to higher energy circuits as a portion of the energy can be dissipated in the external dump resistor. Dump- switches require less material and triggering energy as a lower switch resistance is needed to achieve the required total dump resistance. Both superconducting bypass-switches and superconducting dump-switches can be ther- mally activated. Switching times that are comparable to those obtained with mechanical bypass-switch systems can be achieved using a co-wound heater that is powered by a ca- pacitor discharge. Switches that have fast thermal diffusion times through the insulation can be modelled as a lumped system whereas those with slow thermal diffusion times were modelle...

  2. Turbomachinery Clearance Control

    Science.gov (United States)

    Chupp, Raymond E.; Hendricks, Robert C.; Lattime, Scott B.; Steinetz, Bruce M.; Aksit, Mahmut F.

    2007-01-01

    Controlling interface clearances is the most cost effective method of enhancing turbomachinery performance. Seals control turbomachinery leakages, coolant flows and contribute to overall system rotordynamic stability. In many instances, sealing interfaces and coatings are sacrificial, like lubricants, giving up their integrity for the benefit of the component. They are subjected to abrasion, erosion, oxidation, incursive rubs, foreign object damage (FOD) and deposits as well as extremes in thermal, mechanical, aerodynamic and impact loadings. Tribological pairing of materials control how well and how long these interfaces will be effective in controlling flow. A variety of seal types and materials are required to satisfy turbomachinery sealing demands. These seals must be properly designed to maintain the interface clearances. In some cases, this will mean machining adjacent surfaces, yet in many other applications, coatings are employed for optimum performance. Many seals are coating composites fabricated on superstructures or substrates that are coated with sacrificial materials which can be refurbished either in situ or by removal, stripping, recoating and replacing until substrate life is exceeded. For blade and knife tip sealing an important class of materials known as abradables permit blade or knife rubbing without significant damage or wear to the rotating element while maintaining an effective sealing interface. Most such tip interfaces are passive, yet some, as for the high-pressure turbine (HPT) case or shroud, are actively controlled. This work presents an overview of turbomachinery sealing. Areas covered include: characteristics of gas and steam turbine sealing applications and environments, benefits of sealing, types of standard static and dynamics seals, advanced seal designs, as well as life and limitations issues.

  3. Hybrid High-Temperature Superconductor Current Leads for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Tai-Yang Research Company (TYRC) of Tallahassee, Florida proposes to build hybrid high-temperature superconducting current leads for space applications,...

  4. X-Aerogels for Structural Components and High Temperature Applications

    Science.gov (United States)

    2005-01-01

    Future NASA missions and space explorations rely on the use of materials that are strong ultra lightweight and able to withstand extreme temperatures. Aerogels are low density (0.01-0.5 g/cu cm) high porosity materials that contain a glass like structure formed through standard sol-gel chemistry. As a result of these structural properties, aerogels are excellent thermal insulators and are able to withstand temperatures in excess of l,000 C. The open structure of aerogels, however, renders these materials extremely fragile (fracturing at stress forces less than 0.5 N/sq cm). The goal of NASA Glenn Research Center is to increase the strength of these materials by templating polymers and metals onto the surface of an aerogel network facilitating the use of this material for practical applications such as structural components of space vehicles used in exploration. The work this past year focused on two areas; (1) the research and development of new templated aerogels materials and (2) process development for future manufacturing of structural components. Research and development occurred on the production and characterization of new templating materials onto the standard silica aerogel. Materials examined included polymers such as polyimides, fluorinated isocyanates and epoxies, and, metals such as silver, gold and platinum. The final properties indicated that the density of the material formed using an isocyanate is around 0.50 g/cc with a strength greater than that of steel and has low thermal conductivity. The process used to construct these materials is extremely time consuming and labor intensive. One aspect of the project involved investigating the feasibility of shortening the process time by preparing the aerogels in the templating solvent. Traditionally the polymerization used THF as the solvent and after several washes to remove any residual monomers and water, the solvent around the aerogels was changed to acetonitrile for the templating step. This process

  5. TIGGERC: Turbomachinery Interactive Grid Generator for 2-D Grid Applications and Users Guide

    Science.gov (United States)

    Miller, David P.

    1994-01-01

    A two-dimensional multi-block grid generator has been developed for a new design and analysis system for studying multiple blade-row turbomachinery problems. TIGGERC is a mouse driven, interactive grid generation program which can be used to modify boundary coordinates and grid packing and generates surface grids using a hyperbolic tangent or algebraic distribution of grid points on the block boundaries. The interior points of each block grid are distributed using a transfinite interpolation approach. TIGGERC can generate a blocked axisymmetric H-grid, C-grid, I-grid or O-grid for studying turbomachinery flow problems. TIGGERC was developed for operation on Silicon Graphics workstations. Detailed discussion of the grid generation methodology, menu options, operational features and sample grid geometries are presented.

  6. Silicon carbide-based hydrogen gas sensors for high-temperature applications.

    Science.gov (United States)

    Kim, Seongjeen; Choi, Jehoon; Jung, Minsoo; Joo, Sungjae; Kim, Sangchoel

    2013-10-09

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures.

  7. Perspectives of High-Temperature Thermoelectric Applications and p-type and n-type Aluminoborides

    Science.gov (United States)

    Mori, T.

    2016-10-01

    A need exists to develop high-temperature thermoelectric materials which can utilize high-temperature unutilized/waste heat in thermal power plants, steelworks, factories, incinerators, etc., and also focused solar power. The thermal power plant topping application is of potential high impact since it can sizably increase the efficiency of power plants which are the major supply of electrical power for many countries. Higher borides are possible candidates for their particular high-temperature stability, generally large Seebeck coefficients, α, and intrinsic low thermal conductivity. Excellent (|α| > 200 μV/K) p-type or n-type behavior was recently achieved in the aluminoboride YAl x B14 by varying the occupancy of Al sites, x. Finding p-type and n-type counterparts has long been a difficulty of thermoelectric research not limited to borides. This paper reviews possible high-temperature thermoelectric applications, and recent developments and perspectives of thermoelectric aluminoborides.

  8. Silicon Carbide-Based Hydrogen Gas Sensors for High-Temperature Applications

    OpenAIRE

    Sangchoel Kim; Jehoon Choi; Minsoo Jung; Seongjeen Kim; Sungjae Joo

    2013-01-01

    We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS) structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5) layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC) was used as a substrate ...

  9. The feasibility and application of gray scale adjustment method in high temperature digital image correlation

    Science.gov (United States)

    Wang, Shen; Yao, Xue Feng; Su, Yun Quan; Liu, Wei

    2017-02-01

    In this paper, the basic principle and application of linear gray scale adjustment method are investigated in high temperature digital image correlation (DIC) technology. First, the simple linear gray scale adjustment method is proposed, which can adjust the gray scale value of the saturated pixels and diminish the correlation error caused by the saturated pixels. Then, both the simulated high temperature images and DIC correlation results before and after the gray scale adjustment are provided and analyzed to verify its effectiveness, in which the displacement error decreased from 0.1 pixels to 0.04 pixels after the linear gray scale adjustment for high temperature images. Finally, the linear gray scale adjustment method is used to extract the displacement with high accuracy in high temperature experiment of SiC specimen, and the displacement error decreased from 0.5 pixels to 0.1 pixels after the linear gray scale adjustment.

  10. High temperature, radiation hardened electronics for application to nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Gover, J.E.

    1980-01-01

    Electronic circuits were developed and built at Sandia for many aerospace and energy systems applications. Among recent developments were high temperature electronics for geothermal well logging and radiation hardened electronics for a variety of aerospace applications. Sandia has also been active in technology transfer to commercial industry in both of these areas.

  11. Turbomachinery; Turbomaquinaria

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, Elena [ed.] [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    The fossil fuel power stations have a large number of rotary equipment that faces diverse problems that do necessary to improve the present practices of operation and maintenance. In this article are presented the main systems that the Instituto de Investigaciones Electricas (IIE) offers nowadays for the predictive maintenance of rotary equipment in fossil fuel power plants developed by the Management of Turbomachinery. The systems that are described are: the Portable one, the SICAD (Computerized System for Dynamic Analysis), the SMC (Continuous Monitoring System) and finally the SIMPER (Computer Information System for the Predictive Maintenance of Rotary Equipment) [Spanish] Las centrales termoelectricas cuentan con una gran cantidad de equipo rotatorio que enfrenta diversos problemas que hacen necesario mejorar las practicas actuales de operacion y mantenimiento. En este articulo se presentan los principales sistemas que ofrece actualmente el Instituto de Investigaciones Electricas (IIE) para el mantenimiento predictivo de equipos rotatorios en centrales termoelectricas desarrollados en la Gerencia de Turbomaquinaria. Los sistemas que se describen son; el Portil, el Sicad ( Sistema Computarizado para Analisis Dinamico), el SMC ( Sistema de Monitoreo Continuo) y por ultimo el SIMPER (Sistema Informatico para el mantenimiento Predictivo de Equipo Rotatorio)

  12. An overview of die-attach material for high temperature applications

    Science.gov (United States)

    Tan, Kim Seah; Noordin, Norasiah Mohammad; Cheong, Kuan Yew

    2017-07-01

    Die attachment is an essential process to bring together a semiconductor die to a physical substrate in an electronic package. The material that used to "glue" the die and substrate is termed as die-attach material. The die-attach material and its attachment process must demonstrate a few essential characteristics in order to meet a stringent requirement in particular for devices employed for high temperature applications. Definition of high temperature devices and applications has been explained. Five key type materials for high temperature die-attach application being reported in literatures and in industries have been elaborated, differentiated, and reviewed. Design requirements, selection criteria, and technological considerations have also been presented in this manuscript.

  13. A Review of TiNiPdCu Alloy System for High Temperature Shape Memory Applications

    Science.gov (United States)

    Khan, M. Imran; Kim, Hee Young; Miyazaki, Shuichi

    2015-06-01

    High temperature shape memory alloys (HTSMAs) are important smart materials and possess a significant potential to improve many engineering systems. Many TiNi-based high temperature ternary alloy systems have been reported in literature including TiNiPd, TiNiPt, TiNiZr, TiNiAu, TiNiHf, etc. Some quaternary additions of certain elements in the above systems have been successful to further improve many important shape memory and mechanical properties. The success criteria for an HTSMA become strict in terms of its cyclic stability, maximum recoverable strain, creep resistance, and corrosion resistance at high temperatures. TiNiPdCu alloy system has been recently proposed as a promising HTSMA. Unique nanoscaled precipitates formed in TiNiPdCu-based HTSMAs are found to be stable at temperatures above 773 K, while keeping the benefits of ease of fabrication. It is expected that this alloy system possesses significant potential especially for the high temperature shape memory applications. Till now many research reports have been published on this alloy system. In the present work, a comprehensive review of the TiNiPdCu system is presented in terms of thermomechanical behavior, nanoscale precipitation mechanism, microstructural features, high temperature shape memory and mechanical properties, and the important parameters to control the high temperature performance of these alloys.

  14. High Temperature Superconductivity in the Past Twenty Years Part 2-Towards to Practical Applications

    Institute of Scientific and Technical Information of China (English)

    Jian-Xun Jin

    2008-01-01

    After discovering high temperature super- conducting materials 20 years ago, the preparation of applicable HTS materials has been pursued along with HTS mechanism and characteristic study. At present, the focus on the applied HTS technology has been moving to the industrial preparations from the laboratory research stage, and the technology has been well verified for practical applications from small to large scales. The fabrication techniques of engineering HTS materials are being industrialized; and various HTS devices are also on the way towards practical applications. This paper provides a comprehensive summary on the applied high temperature superconductivity with regard to various applicable HTS materials, their preparation techniques and charac- terization, and applications in a wide range.

  15. Stainless steel component with compressed fiber Bragg grating for high temperature sensing applications

    Science.gov (United States)

    Jinesh, Mathew; MacPherson, William N.; Hand, Duncan P.; Maier, Robert R. J.

    2016-05-01

    A smart metal component having the potential for high temperature strain sensing capability is reported. The stainless steel (SS316) structure is made by selective laser melting (SLM). A fiber Bragg grating (FBG) is embedded in to a 3D printed U-groove by high temperature brazing using a silver based alloy, achieving an axial FBG compression of 13 millistrain at room temperature. Initial results shows that the test component can be used for up to 700°C for sensing applications.

  16. Thick sputtered tantalum coatings for high-temperature energy conversion applications

    Energy Technology Data Exchange (ETDEWEB)

    Stelmakh, Veronika, E-mail: stelmakh@mit.edu; Peykov, Daniel; Chan, Walker R.; Senkevich, Jay J.; Joannopoulos, John D.; Soljačić, Marin; Celanovic, Ivan [Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Castillo, Robert; Coulter, Kent; Wei, Ronghua [Materials Engineering Department, Southwest Research Institute, San Antonio, Texas 78238 (United States)

    2015-11-15

    Thick sputtered tantalum (Ta) coatings on polished Inconel were investigated as a potential replacement for bulk refractory metal substrates used for high-temperature emitters and absorbers in thermophotovoltaic energy conversion applications. In these applications, high-temperature stability and high reflectance of the surface in the infrared wavelength range are critical in order to sustain operational temperatures and reduce losses due to waste heat. The reflectance of the coatings (8 and 30 μm) was characterized with a conformal protective hafnia layer as-deposited and after one hour anneals at 700, 900, and 1100 °C. To further understand the high-temperature performance of the coatings, the microstructural evolution was investigated as a function of annealing temperature. X-ray diffraction was used to analyze the texture and residual stress in the coatings at four reflections (220, 310, 222, and 321), as-deposited and after anneal. No significant changes in roughness, reflectance, or stress were observed. No delamination or cracking occurred, even after annealing the coatings at 1100 °C. Overall, the results of this study suggest that the thick Ta coatings are a promising alternative to bulk substrates and pave the way for a relatively low-cost and easily integrated platform for nanostructured devices in high-temperature energy conversion applications.

  17. AMSAHTS 1990: Advances in Materials Science and Applications of High Temperature Superconductors

    Science.gov (United States)

    Bennett, Larry H. (Editor); Flom, Yury (Editor); Moorjani, Kishin (Editor)

    1991-01-01

    This publication is comprised of abstracts for oral and poster presentations scheduled for AMSAHTS '90. The conference focused on understanding high temperature superconductivity with special emphasis on materials issues and applications. AMSAHTS 90, highlighted the state of the art in fundamental understanding of the nature of high-Tc superconductivity (HTSC) as well as the chemistry, structure, properties, processing and stability of HTSC oxides. As a special feature of the conference, space applications of HTSC were discussed by NASA and Navy specialists.

  18. Development of UHTC- Ultra-high-temperature ceramics for aerospace and industrial applications

    OpenAIRE

    Bellosi, Alida

    2009-01-01

    Zirconium and Hafnium diborides and carbides belong to the class of Ultra-High-Temperature Ceramics (UHTC) for their high melting point (2700-3900?C). The interest on these materials is due to the unique combination of properties 8High hardness, high electrical and thermal conductivity, chemical inertness). They constitute a clss of promising materials for HT applications in industrial secors like foundry, refractory or nuclear plants. Applications are also found in aerospace industry: leadin...

  19. Ultra-High-Temperature-Ceramics: potentialities and barriers to the application in hot structures

    OpenAIRE

    Bellosi, Alida

    2009-01-01

    High performance Ultra-High-Temperature Composites (based on zirconium-, hafnium-, tantalum- borides and carbides) are characterized by relevant and unique thermo-physical and thermo-mechanical properties, suitable for applications in thermo-protection systems for aerospace applications. In spite of the difficult sinterability of borides and carbides of Zr, Hf, Ta, recent results highlighted that UHTC ceramics can be successfully produced with full density, fine and uniform microstructure and...

  20. Advances in Ceramic Matrix Composite Blade Damping Characteristics for Aerospace Turbomachinery Applications

    Science.gov (United States)

    Min, James B.; Harris, Donald L.; Ting, J. M.

    2011-01-01

    For advanced aerospace propulsion systems, development of ceramic matrix composite integrally-bladed turbine disk technology is attractive for a number of reasons. The high strength-to-weight ratio of ceramic composites helps to reduce engine weight and the one-piece construction of a blisk will result in fewer parts count, which should translate into reduced operational costs. One shortcoming with blisk construction, however, is that blisks may be prone to high cycle fatigue due to their structural response to high vibration environments. Use of ceramic composites is expected to provide some internal damping to reduce the vibratory stresses encountered due to unsteady flow loads through the bladed turbine regions. A goal of our research was to characterize the vibration viscous damping behavior of C/SiC composites. The vibration damping properties were measured and calculated. Damping appeared to decrease with an increase in the natural frequency. While the critical damping amount of approximately 2% is required for typical aerospace turbomachinery engines, the C/SiC damping at high frequencies was less than 0.2% from our study. The advanced high-performance aerospace propulsion systems almost certainly will require even more damping than what current vehicles require. A purpose of this paper is to review some work on C/SiC vibration damping by the authors for the NASA CMC turbine blisk development program and address an importance of the further investigation of the blade vibration damping characteristics on candidate CMC materials for the NASA s advanced aerospace turbomachinery engine systems.

  1. First-principles prediction of new complex transition metal hydrides for high temperature applications.

    Science.gov (United States)

    Nicholson, Kelly M; Sholl, David S

    2014-11-17

    Metal hydrides with high thermodynamic stability are desirable for high-temperature applications, such as those that require high hydrogen release temperatures or low hydrogen overpressures. First-principles calculations have been used previously to identify complex transition metal hydrides (CTMHs) for high temperature use by screening materials with experimentally known structures. Here, we extend our previous screening of CTMHs with a library of 149 proposed materials based on known prototype structures and charge balancing rules. These proposed materials are typically related to known materials by cation substitution. Our semiautomated, high-throughput screening uses density functional theory (DFT) and grand canonical linear programming (GCLP) methods to compute thermodynamic properties and phase diagrams: 81 of the 149 materials are found to be thermodynamically stable. We identified seven proposed materials that release hydrogen at higher temperatures than the associated binary hydrides and at high temperature, T > 1000 K, for 1 bar H2 overpressure. Our results indicate that there are many novel CTMH compounds that are thermodynamically stable, and the computed thermodynamic data and phase diagrams should be useful for selecting materials and operating parameters for high temperature metal hydride applications.

  2. Low Cycle Fatigue Behaviors of Alloy 617 (INCONEL 617 Weldments for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Rando Tungga Dewa

    2016-04-01

    Full Text Available In this study, we comparatively investigate the low cycle fatigue behavior of Alloy 617 (INCONEL 617 weldments by gas tungsten arc welding process at room temperature and 800 °C in the air to support the qualification in high temperature applications of the Next Generation-IV Nuclear Plant. Axial total-strain controlled tests have been performed with the magnitude of strain ranges with a constant strain ratio (Rε = −1. The results of fatigue tests consistently show lower fatigue life with an increase in total strain range and temperature at all testing conditions. The reduction in fatigue life may result from the higher cyclic plastic strain accumulation and the material ductility at high temperature conditions. A constitutive behavior of high temperature by some cyclic hardening was observed. The occurrence of serrated yielding in the cyclic stress response was also observed, suggesting the influence of dynamic strain aging during high temperature. We evaluated a well-known life prediction model through the Coffin-Manson relationship. The results are well matched with the experimental data. In addition, low cycle fatigue cracking occurred in the weld metal region and initiated transgranularly at the free surface.

  3. Application of TL dosemeters for dose distribution measurements at high temperatures in nuclear reactors.

    Science.gov (United States)

    Osvay, M; Deme, S

    2006-01-01

    Al2O3:Mg,Y ceramic thermoluminescence dosemeters were developed at the Institute of Isotopes for high dose applications at room temperatures. The glow curve of Al2O3:Mg,Y exhibits two peaks--one at 250 degrees C (I) and another peak at approximately 400 degrees C (II). In order to extend the application of these dosemeters to high temperatures, the effect of irradiation temperature was investigated using temperature controlled heating system during high dose irradiation at various temperatures (20-100 degrees C). The new calibration and measuring method has been successfully applied for dose mapping within the hermetic zone of the Paks Nuclear Power Plant even at high temperature parts of blocks.

  4. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  5. Ceramic fibers for matrix composites in high-temperature engine applications

    Science.gov (United States)

    Baldus; Jansen; Sporn

    1999-07-30

    High-temperature engine applications have been limited by the performance of metal alloys and carbide fiber composites at elevated temperatures. Random inorganic networks composed of silicon, boron, nitrogen, and carbon represent a novel class of ceramics with outstanding durability at elevated temperatures. SiBN(3)C was synthesized by pyrolysis of a preceramic N-methylpolyborosilazane made from the single-source precursor Cl(3)Si-NH-BCl(2). The polymer can be processed to a green fiber by melt-spinning, which then undergoes an intermediate curing step and successive pyrolysis. The ceramic fibers, which are presently produced on a semitechnical scale, combine several desired properties relevant for an application in fiber-reinforced ceramic composites: thermal stability, mechanical strength, high-temperature creep resistivity, low density, and stability against oxidation or molten silicon.

  6. Evaluation of high temperature dielectric films for high voltage power electronic applications

    Science.gov (United States)

    Suthar, J. L.; Laghari, J. R.

    1992-01-01

    Three high temperature films, polyimide, Teflon perfluoroalkoxy and poly-P-xylene, were evaluated for possible use in high voltage power electronic applications, such as in high energy density capacitors, cables and microelectronic circuits. The dielectric properties, including permittivity and dielectric loss, were obtained in the frequency range of 50 Hz to 100 kHz at temperatures up to 200 C. The dielectric strengths at 60 Hz were determined as a function of temperature to 250 C. Confocal laser microscopy was performed to diagnose for voids and microimperfections within the film structure. The results obtained indicate that all films evaluated are capable of maintaining their high voltage properties, with minimal degradation, at temperatures up to 200 C. However, above 200 C, they lose some of their electrical properties. These films may therefore become viable candidates for high voltage power electronic applications at high temperatures.

  7. Transient modeling of the thermohydraulic behavior of high temperature heat pipes for space reactor applications

    Science.gov (United States)

    Hall, Michael L.; Doster, Joseph M.

    1986-01-01

    Many proposed space reactor designs employ heat pipes as a means of conveying heat. Previous researchers have been concerned with steady state operation, but the transient operation is of interest in space reactor applications due to the necessity of remote startup and shutdown. A model is being developed to study the dynamic behavior of high temperature heat pipes during startup, shutdown and normal operation under space environments. Model development and preliminary results for a hypothetical design of the system are presented.

  8. Construction Of A Piezoelectric-Based Resonance Ceramic Pressure Sensor Designed For High-Temperature Applications

    OpenAIRE

    Belavič Darko; Bradeško Andraž; Zarnik Marina Santo; Rojac Tadej

    2015-01-01

    In this work the design aspects of a piezoelectric-based resonance ceramic pressure sensor made using low-temperature co-fired ceramic (LTCC) technology and designed for high-temperature applications is presented. The basic pressure-sensor structure consists of a circular, edge-clamped, deformable diaphragm that is bonded to a ring, which is part of the rigid ceramic structure. The resonance pressure sensor has an additional element – a piezoelectric actuator – for stimulating oscillation of ...

  9. Sintering and properties of Ultra High Temperature Ceramics for aerospace applications

    OpenAIRE

    Justin, J.F.

    2013-01-01

    The Ultra High Temperature Ceramics (UHTCs) represent a very interesting family of materials and therefore they are the subject of increasing attention from different engineering sectors and notably the aerospace industry. Indeed, hypersonic flights, re-entry vehicles, propulsion applications and so on, require new materials that can perform in oxidizing or corrosive atmospheres at temperatures higher than 2000°C and sometimes, for long life-time. To fulfil these requirements, UHTCs seems to ...

  10. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

    Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  11. High temperature metal hydrides as heat storage materials for solar and related applications.

    Science.gov (United States)

    Felderhoff, Michael; Bogdanović, Borislav

    2009-01-01

    For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 degrees C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

  12. Realization of High-temperature Superconductivity in Nano-carbon Materials and Its Application

    Science.gov (United States)

    2015-07-13

    hottest topics in condensed matter physics and also for application to zero- emission energy system. In particular, carbon-based superconductors have...nano- carbon materials and its application II 5a. CONTRACT NUMBER FA2386-13-1-4059 5b. GRANT NUMBER Grant 13RSZ067_134059 5c. PROGRAM ELEMENT...for AOARD Grant F A2386-13- l-4059 "Realization of high-temperature superconductivity in nano-carbon materials and its application " Date: 07/13

  13. Turbomachinery Performance Map Application for Analyzing Cycle Off-Design Behavior of KAIST MMR

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Seong Kuk; Lee, Jekyoung; Kim, Seong Gu; Lee, Jeong Ik [KAIST, Daejeon (Korea, Republic of)

    2015-05-15

    The steam Rankine cycle has been mainly applied in the Power Conversion Unit (PCU) of the existing SMRs. For this reason, modularization and downsizing of the nuclear power plant including PCU is difficult due to complexity and large volume. To solve these problems, KAIST research team proposed a new concept of SMR, called KAIST MMR (Micro Modular Reactor), which utilizes S-CO2 as the working fluid. Due to high density of S-CO2 and the development of heat exchanger technology, such as the printed circuit heat exchanger (PCHE), it can achieve small PCU and modularization of system. This paper describes the method of performance maps to predict the turbomachinery performance for different inlet conditions. One of the most well-known methods is equivalent conditions which include corrected mass flow, corrected total enthalpy rise, and corrected speed. Appropriate performance at any conditions which are different from the design condition can be calculated. As further works, the predicted data from KAIST{sub T}MD will be compared to other experimental data. Also turbine code will be validated.

  14. Nano Structured Plasma Spray Coating for Wear and High Temperature Corrosion Resistance Applications

    Science.gov (United States)

    Ghosh, D.; Shukla, A. K.; Roy, H.

    2014-04-01

    The nano structured coating is a major challenge today to improve the different mechanical properties, wear and high temperature corrosion resistance behaviour of different industrial alloys. This paper is a review on synthesis of nano powder, plasma spraying methods, techniques of nano structured coating by plasma spray method, mechanical properties, tribological properties and high temperature corrosion behaviour of nano structured coating. Nano structured coatings of ceramic powders/composites are being developed for wide variety of applications like boiler, turbine and aerospace industries, which requires the resistance against wear, corrosion, erosion etc. The nano sized powders are subjected to agglomeration by spray drying, after which nano structured coating can be successfully applied over the substrate. Nano structured coating shows improved mechanical wear resistance and high temperature corrosion resistance. The significant improvement of wear and corrosion resistance is mainly attributed to formation of semi molten nano zones in case of nano structured coatings. The future scope of application of nano structured coating has also been highlighted in this paper.

  15. High-frequency applications of high-temperature superconductor thin films

    Science.gov (United States)

    Klein, N.

    2002-10-01

    High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz.

  16. Processing and Characterization of Basalt Fiber Reinforced Ceramic Composites for High Temperature Applications Using Polymer Precursors

    Science.gov (United States)

    Cox, Sarah B.; Lui, Donovan; Gou, Jihua

    2014-01-01

    The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The two PDCs used in this development are polysiloxane and polycarbosilane. Polysiloxanes contain a silicon oxycarbide backbone when pyrolized up to 1000C. Polycarbosilane, an organosilicon polymer, contain a silicon-carbon backbone; around 1200C, beta-SiC begins to crystallize. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in composites. Basalt is a naturally occurring material found in volcanic rock. Continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. Thermal and mechanical testing includes oxyacetylene torch testing and three point bend testing.

  17. Heat transfer capability simulation of high-temperature heat pipe in supersonic vehicle leading edge applications

    Directory of Open Access Journals (Sweden)

    Donghuan Liu

    2016-04-01

    Full Text Available A numerical method is proposed to determine the heat transfer capability of the high-temperature heat pipe and the stagnation temperature with supersonic vehicle leading edge applications. The finite element method is employed here to perform the temperature field simulation. Without considering the heat transfer limitations of the heat pipe, such as capillary limit and sonic limit, both numerical and experimental results indicate that equivalent high thermal conductivity method is a reasonable way to simulate the heat transfer capability of the high-temperature heat pipe in preliminary design of a heat-pipe-cooled leading edge. Several important parameters’ effects on the thermal protection performance are also numerically investigated.

  18. Nanostructure-based proton exchange membrane for fuel cell applications at high temperature.

    Science.gov (United States)

    Li, Junsheng; Wang, Zhengbang; Li, Junrui; Pan, Mu; Tang, Haolin

    2014-02-01

    As a clean and highly efficient energy source, the proton exchange membrane fuel cell (PEMFC) has been considered an ideal alternative to traditional fossil energy sources. Great efforts have been devoted to realizing the commercialization of the PEMFC in the past decade. To eliminate some technical problems that are associated with the low-temperature operation (such as catalyst poisoning and poor water management), PEMFCs are usually operated at elevated temperatures (e.g., > 100 degrees C). However, traditional proton exchange membrane (PEM) shows poor performance at elevated temperature. To achieve a high-performance PEM for high temperature fuel cell applications, novel PEMs, which are based on nanostructures, have been developed recently. In this review, we discuss and summarize the methods for fabricating the nanostructure-based PEMs for PEMFC operated at elevated temperatures and the high temperature performance of these PEMs. We also give an outlook on the rational design and development of the nanostructure-based PEMs.

  19. Optimization of usage parameters of ceramic coatings in high temperature applications using Taguchi design

    Directory of Open Access Journals (Sweden)

    Mohammed Yunus

    2011-08-01

    Full Text Available The durability and efficiency of high temperature components used in aerospace industry are improved by the usage of thermal barrier coatings (TBC.The characterization of TBC requires a better understanding of mechanical and tribological properties along with their failure mechanisms which are to be thoroughly investigatedto estimate their performance. Thermal barrier (TB and thermal cycling resistance (TCR parameters are considered to be very important at high temperature applications. Thermal tests were carried out on three different types of coatings namely, Alumina (A, Alumina-Titania (AT and partially stabilized zirconia (PSZ, in the present study. Using Taguchi approach, optimization of various TBC parameters like temperature on heated surface of coating,thicknesses and types of coatings was done and the significance of TB and TCR were also investigated using S/N ratio and ANOVA. The experimental results were found to be in good agreement with statistical results obtained by Taguchi technology.

  20. Computational methods for internal flows with emphasis on turbomachinery

    Science.gov (United States)

    Mcnally, W. D.; Sockol, P. M.

    1981-01-01

    Current computational methods for analyzing flows in turbomachinery and other related internal propulsion components are presented. The methods are divided into two classes. The inviscid methods deal specifically with turbomachinery applications. Viscous methods, deal with generalized duct flows as well as flows in turbomachinery passages. Inviscid methods are categorized into the potential, stream function, and Euler aproaches. Viscous methods are treated in terms of parabolic, partially parabolic, and elliptic procedures. Various grids used in association with these procedures are also discussed.

  1. A survey of possible passive antenna applications of high-temperature superconductors

    Science.gov (United States)

    Dinger, Robert J.; Bowling, Donald R.; Martin, Anna M.

    1991-09-01

    A survey of possible applications of high-temperature superconductors (HTSs) to antennas and antenna feed networks is presented. The frequency range considered is 1 MHz to 100 GHz. Three antenna application areas seem appropriate for HTS material: electrically small antennas and their matching networks; feed and matching networks for compact arrays with enhanced directive gain (superdirective arrays); and feed networks for millimeter-wave arrays. Preliminary experimental results are presented on YBaCuO and TBaCaCuO 500 MHz half-loop antennas that show an increase in radiation efficiency (compared with a copper antenna at the same temperature) by a factor of 5 for the HTS antennas.

  2. Assessment of very high-temperature reactors in process applications. Appendix III. Engineering evaluation of process heat applications for very-high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Wiggins, D.S.; Williams, J.J.

    1977-04-01

    An engineering and economic evaluation is made of coal conversion processes that can be coupled to a very high-temperature nuclear reactor heat source. The basic system developed by General Atomic/Stone and Webster (GA/S and W) is similar to the H-coal process developed by Hydrocarbon Research, Inc., but is modified to accommodate a nuclear heat source and to produce synthetic natural gas (SNG), synthesis gas, and hydrogen in addition to synthetic crude liquids. The synthetic crude liquid production is analyzed by using the GA/S and W process coupled to either a nuclear- or fossil-heat source. Four other processes are included for comparison: (1) the Lurgi process for production of SNG, (2) the Koppers-Totzek process for production of either hydrogen or synthesis gas, (3) the Hygas process for production of SNG, and (4) the Westinghouse thermal-chemical water splitting process for production of hydrogen. The production of methanol and iron ore reduction are evaluated as two potential applications of synthesis gas from either the GA/S and W or Koppers-Totzek processes. The results indicate that the product costs for each of the gasification and liquefaction processes did not differ significantly, with the exception that the unproven Hygas process was cheaper and the Westinghouse process considerably more expensive than the others.

  3. Oil-Free Turbomachinery Technologies for Long-Life, Maintenance-Free Power Generation Applications

    Science.gov (United States)

    Dellacorte, Christopher

    2013-01-01

    Turbines have long been used to convert thermal energy to shaft work for power generation. Conventional turbines rely upon oil-lubricated rotor supports (bearings, seals, etc.) to achieve low wear, high efficiency and reliability. Emerging Oil-Free technologies such as gas foil bearings and magnetic bearings offer a path for reduced weight and complexity and truly maintenance free systems. Oil-Free gas turbines, using gaseous and liquid fuels are commercially available in power outputs to at least 250kWe and are gaining acceptance for remote power generation where maintenance is a challenge. Closed Brayton Cycle (CBC) turbines are an approach to power generation that is well suited for long life space missions. In these systems, a recirculating gas is heated by nuclear, solar or other heat energy source then fed into a high-speed turbine that drives an electrical generator. For closed cycle systems such as these, the working fluid also passes through the bearing compartments thus serving as a lubricant and bearing coolant. Compliant surface foil gas bearings are well suited for the rotor support systems of these advanced turbines. Foil bearings develop a thin hydrodynamic gas film that separates the rotating shaft from the bearing preventing wear. During start-up and shut down when speeds are low, rubbing occurs. Solid lubricants are used to reduce starting torque and minimize wear. Other emerging technologies such as magnetic bearings can also contribute to robust and reliable Oil-Free turbomachinery. In this presentation, Oil-Free technologies for advanced rotor support systems will be reviewed as will the integration and development processes recommended for implementation.

  4. Development of a design methodology for high temperature cyclic applications of materials which experience cyclic softening

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L.; Stubbins, J.F. (Illinois Univ., Urbana, IL (USA). Dept. of Mechanical and Industrial Engineering)

    1988-12-01

    The project has as its original focus the high temperature behavior of 2.25 Cr-1 Mo steel, heat treated to produce a predominantly bainitic microstructure and the load carrying response of components made of this material. Experiments were carried out on uniform and notched specimens under both steady and cyclic loading using specially acquired electromechanical test machines. It emerged that a very important feature of mechanical behavior under the conditions of interest was the strong tendency of this material to cyclically soften, particularly at high temperature in the creep range, giving the illusion of a severe creep-fatigue interaction under certain conditions. This finding led to a significant component of the project being devoted to investigation of the effects of local, as opposed to generalized, cyclic softening, and the implications this phenomenon might have on the setting of allowable design stress limits. The format of this report is as follows: The second chapter is a review of the work carried out in approximately chronological order under the headings of work was carried out under the following: (1) 2.25 Cr 1 Mo Steel -- Elevated Temperature Fatigue and Environmental Effects; (2) Preliminary Studies of Advanced Austenitics; (3) A Uniaxial Constitutive Model for Cyclic Softening; (4) The Iso-Cyclic Stress-Strain Approach to Evaluation of Components in Cyclic Softening Materials; (5) Testing of High Temperature Austenitic Alloys; and (6) Design Methodology for Aging Materials -- Application to Cyclic Softening. 65 refs., 39 figs., 7 tabs.

  5. Application of High-Temperature Extrinsic Fabry-Perot Interferometer Strain Sensor

    Science.gov (United States)

    Piazza, Anthony

    2008-01-01

    In this presentation to the NASA Aeronautics Sensor Working Group the application of a strain sensor is outlined. The high-temperature extrinsic Fabry-Perot interferometer (EFPI) strain sensor was developed due to a need for robust strain sensors that operate accurately and reliably beyond 1800 F. Specifically, the new strain sensor would provide data for validating finite element models and thermal-structural analyses. Sensor attachment techniques were also developed to improve methods of handling and protecting the fragile sensors during the harsh installation process. It was determined that thermal sprayed attachments are preferable even though cements are simpler to apply as cements are more prone to bond failure and are often corrosive. Previous thermal/mechanical cantilever beam testing of EFPI yielded very little change to 1200 F, with excellent correlation with SG to 550 F. Current combined thermal/mechanical loading for sensitivity testing is accomplished by a furnace/cantilever beam loading system. Dilatometer testing has can also be used in sensor characterization to evaluate bond integrity, evaluate sensitivity and accuracy and to evaluate sensor-to-sensor scatter, repeatability, hysteresis and drift. Future fiber optic testing will examine single-mode silica EFPIs in a combined thermal/mechanical load fixture on C-C and C-SiC substrates, develop a multi-mode Sapphire strain-sensor, test and evaluate high-temperature fiber Bragg Gratings for use as strain and temperature sensors and attach and evaluate a high-temperature heat flux gauge.

  6. Emerging challenges to structural integrity technology for high-temperature applications

    Institute of Scientific and Technical Information of China (English)

    TU Shantung

    2007-01-01

    Structural integrity technology has been widely used with great success for the design, manufacture and failure prevention of modem constructions such as chemical and petrochemical plants, power generation and energy conversion systems, as well as space and oceanic exploration.The modem needs of structural integrity technology are largely attributed to the increase of service temperature of the structures that results in the efficiency improvement in energy conversion and chemical processing technologies. Besides the needs arising from large-scale high-temperature plants,the high tech developments, such as micro chemo-mechanical systems and high-power electronics, provide new challenges to structural integrity technology. The present paper summarizes the recent technical progresses in large process plants and the aviation industry, micro chemo-mechanical systems,fuel cells, high-temperature electronics, and packaging and coating technologies. The state-of-the-art of structural integrity technology for high temperature applications is reviewed.Suggestions are provided for the improvement of current design and assessment methods.

  7. Characterizing the Chemical Stability of High Temperature Materials for Application in Extreme Environments

    Science.gov (United States)

    Opila, Elizabeth

    2005-01-01

    The chemical stability of high temperature materials must be known for use in the extreme environments of combustion applications. The characterization techniques available at NASA Glenn Research Center vary from fundamental thermodynamic property determination to material durability testing in actual engine environments. In this paper some of the unique techniques and facilities available at NASA Glenn will be reviewed. Multiple cell Knudsen effusion mass spectrometry is used to determine thermodynamic data by sampling gas species formed by reaction or equilibration in a Knudsen cell held in a vacuum. The transpiration technique can also be used to determine thermodynamic data of volatile species but at atmospheric pressures. Thermodynamic data in the Si-O-H(g) system were determined with this technique. Free Jet Sampling Mass Spectrometry can be used to study gas-solid interactions at a pressure of one atmosphere. Volatile Si(OH)4(g) was identified by this mass spectrometry technique. A High Pressure Burner Rig is used to expose high temperature materials in hydrocarbon-fueled combustion environments. Silicon carbide (SiC) volatility rates were measured in the burner rig as a function of total pressure, gas velocity and temperature. Finally, the Research Combustion Lab Rocket Test Cell is used to expose high temperature materials in hydrogen/oxygen rocket engine environments to assess material durability. SiC recession due to rocket engine exposures was measured as a function of oxidant/fuel ratio, temperature, and total pressure. The emphasis of the discussion for all techniques will be placed on experimental factors that must be controlled for accurate acquisition of results and reliable prediction of high temperature material chemical stability.

  8. Processing of continuous fiber reinforced ceramic composites for ultra high temperature applications using organosilicon polymer precursors

    Science.gov (United States)

    Nicholas, James Robert

    The current work is on the development of continuous fiber reinforced ceramic materials (CFCCs) for use in ultra high temperature applications. These applications subject materials to extremely high temperatures(> 2000°C). Monolithic ceramics are currently being used for these applications, but the tendency to fail catastrophically has driven the need for the next generation of material. Reinforcing with continuous fibers significantly improves the toughness of the monolithic materials; however, this is a manufacturing challenge. The development of commercial, low-viscosity preceramic polymers provides new opportunities to fabricate CFCCs. Preceramic polymers behave as polymers at low temperatures and are transformed into ceramics upon heating to high temperatures. The polymer precursors enable the adaptation of well-established polymer processing techniques to produce high quality materials at relatively low cost. In the present work, SMP-10 from Starfire Systems, and PURS from KiON Corp. were used to manufacture ZrB2-SiC/SiC CFCCs using low cost vacuum bagging process in conjunction with the polymer infiltration and pyrolysis process. The microstructure was investigated using scanning electron microscopy and it was determined that the initial greenbody cure produced porosity of both closed and open pores. The open pores were found to be more successfully re-infiltrated using neat resin compared to slurry reinfiltrate; however, the closed pores were found to be impenetrable during subsequent reinfiltrations. The mechanical performance of the manufactured samples was evaluated using flexure tests and found the fiber reinforcement prevented catastrophic failure behavior by increasing fracture toughness. Wedge sample were fabricated and evaluated to demonstrate the ability to produce CFCC of complex geometry.

  9. Development of High-Performance BS-PT Based Piezoelectric Transducers for High-Temperature Applications

    OpenAIRE

    Li, Yu-Hung; Kim, Sang-Jong; Salowitz, Nathan; Chang, Fu-Kuo

    2014-01-01

    International audience; This paper focuses on developing new BiScO3-PbTiO3 (BS-PT) based piezoelectric ceramic transducers for high-temperature SHM applications. By controlling the PbO deficiency in the material system, we modify the lossy ferroelectric properties and enhance the piezoelectric responses from the intrinsic BS-PT. The new in-house fabricated piezoelectric transducers can maintain comparably high piezoelectric responses at temperatures up to 350ÁC continuously for at least 10 ho...

  10. Thermodynamic optimisation and analysis of four Kalina cycle layouts for high temperature applications

    DEFF Research Database (Denmark)

    Modi, Anish; Haglind, Fredrik

    2015-01-01

    The Kalina cycle has seen increased interest in the last few years as an efficient alternative to the conventional steam Rankine cycle. However, the available literature gives little information on the algorithms to solve or optimise this inherently complex cycle. This paper presents a detailed...... approach to solve and optimise a Kalina cycle for high temperature (a turbine inlet temperature of 500°C) and high pressure (over 100bar) applications using a computationally efficient solution algorithm. A central receiver solar thermal power plant with direct steam generation was considered as a case...

  11. Feasibility of Kevlar 49/PMR-15 polyimide for high temperature applications

    Science.gov (United States)

    Hanson, M. P.

    1980-01-01

    Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 to 600 F for the PMR-15 and from 75 to 450 F for the Kevlar 49/3501-6 epoxy material. The study also included the effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths.

  12. Evaluation of CVI SiC/SiC Composites for High Temperature Applications

    Science.gov (United States)

    Kiser, D.; Almansour, A.; Smith, C.; Gorican, D.; Phillips, R.; Bhatt, R.; McCue, T.

    2017-01-01

    Silicon carbide fiber reinforced silicon carbide (SiC/SiC) composites are candidate materials for various high temperature turbine engine applications because of their high specific strength and good creep resistance at temperatures of 1400 C (2552 F) and higher. Chemical vapor infiltration (CVI) SiC/SiC ceramic matrix composites (CMC) incorporating Sylramic-iBN SiC fiber were evaluated via fast fracture tensile tests (acoustic emission damage characterization to assess cracking behavior), tensile creep testing, and microscopy. The results of this testing and observed material behavior degradation mechanisms are reviewed.

  13. Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son

    2003-05-01

    The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.

  14. RESEARCH AND DEVELOPMENT OF HIGH TEMPERATURE STRUCTURAL MATERIALS FOR AERO-ENGINE APPLICATIONS

    Institute of Scientific and Technical Information of China (English)

    G.Q. Zhang

    2005-01-01

    The status of research, development of superalloys and materials processing & fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superalloys for aero-engine disks and rings, and powder metallurgy (PM) superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification,spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.

  15. Processing of Transparent Rare Earth Doped Zirconia for High Temperature Light Emission Applications

    Science.gov (United States)

    Hardin, Corey Lee

    The high fracture toughness of stabilized zirconia makes it one of the most widely applicable high temperature structural materials. However, it is not typicality considered for optical applications since the microstructure achieved by traditional processing makes it opaque. The aim of this dissertation is to develop processing methods for the introducing new functionalities of light transparency and light emission (photoluminescence) and to understand the nanostructure-property relationships that make these functionalities possible. A processing study of rare-earth (RE) doped Zirconium Oxide (ZrO2, zirconia) via Current Activated Pressure Assisted Densification (CAPAD) is presented. The role of processing temperature and dopant concentration on the crystal structure, microstructure and properties of the RE: ZrO2 is studied. Microstructural shows sub-100 nm grain size and homogeneous dopant distribution. X-ray diffraction and Raman analysis show that with increased dopant concentration the material changes from monoclinic to tetragonal. Structural analysis shows the material shows high hardness and toughness values 30% greater than similarly processed yttria-stabilized zirconia. Despite birefringence in the tetragonal phase, optical characterization is presented showing the samples are both highly transparent and photo-luminescent. Special attention is paid to analyzing structural and photoluminescence development during densification, as well as the role of oxygen vacancies on the optical properties of the densified material. This material is shown to be a promising candidate for a number of applications including luminescence thermometry and high temperature light emission.

  16. Commercialization of NASA's High Strength Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    In this paper, the commercialization of a new high strength cast aluminum alloy, invented by NASA-Marshall Space Flight Center, for high temperature applications will be presented. Originally developed to meet U.S. automotive legislation requiring low- exhaust emission, the novel NASA aluminum alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (450 F-750 F), which can lead to reducing part weight and cost as well as improving performance for automotive engine applications. It is an ideal low cost material for cast components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. NASA alloy also offers greater wear resistance, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys, and the new alloy can be produced economically from sand, permanent mold and investment casting. Since 2001, this technology was licensed to several companies for automotive and marine internal combustion engines applications.

  17. Summary of the First Generation High Temperature Superconducting Wire:Processing, Characterization and Applications

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x long wires produced by powder-in-tube techniques, which have been recognized as the first generation of the High Temperature Superconducting (HTS) wires, are expected to apply widely especially in strong current applications. In this work, the processing, characterization and application of the silver-clad (Bi,Pb)2Sr2Ca2Cu3O10+x HTS wires are summarized. The HTS wires are fabricated using the combination of powder-in-tube technique, and the resulting wires are fully characterized by the means of chemical analyses, microstructural observation, electrical and magnetic measurements. The relationship among fabrication parameters, chemical and microstructural characteristics, and electrical and magnetic properties are analyzed. Applications of the HTS wires have also been introduced according to their strong current behaviors with various prototype devices made.

  18. Summary of workshop on alloys for very high-temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-08-01

    In current fossil energy systems, the maximum operating temperatures experienced by critical metal structures do not exceed approximately 732{degrees}C and the major limitation on the use of the alloys typically is corrosion resistance. In systems intended for higher performance and higher efficiency, increasingly higher working fluid temperatures will be employed, which will require materials with higher-temperature capabilities, in particular, higher creep strength and greater environmental resistance. There have been significant developments in alloys in recent years, from modifications of currently-used wrought ferritic and austenitic alloys with the intent of improving their high-temperature capabilities, to oxide dispersion-strengthened alloys targeted at extremely high-temperature applications. The aim of this workshop was to examine the temperature capability of these alloys compared to current alloys, and compared to the needs of advanced fossil fuel combustion or conversion systems, with the goals of identifying where modified/new alloys would be expected to find application, their limitations, and the information/actions required or that are being taken to qualify them for such use.

  19. Supersonic Two-Dimensional Minimum Length Nozzle Design at High Temperature. Application for Air

    Institute of Scientific and Technical Information of China (English)

    Toufik Zebbiche; ZineEddine Youbi

    2007-01-01

    When the stagnation temperature of a perfect gas increases, the specific heat ratio does not remain constant any more, and start to vary with this temperature. The gas remains perfect, its state equation remains always valid, except it will name in more calorically imperfect gas or gas at High Temperature. The goal of this work is to trace the profiles of the supersonic Minimum Length Nozzle with centered expansion when the stagnation temperature is taken into account, lower than the threshold of dissociation of the molecules and to have for each exit Mach number several nozzles shapes by changing the value of the temperature. The method of characteristics is used with a new form of the Prandtl Meyer function at high temperature. The resolution of the obtained equations is done by the second order of finite differences method by using the predictor corrector algorithm. A study on the error given by the perfect gas model compared to our model is presented. The comparison is made with a calorically perfect gas for goal to give a limit of application of this model.The application is for the air.

  20. Application of phase diagram calculations to development of new ultra-high temperature structural materials

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In-situ refractory metal intermetallic composites(RMICs) based either on (Nb, Si) or (Mo, Si, B) are candidate materials for ultra-high temperature applications (> 1 400 ℃). To provide a balance of mechanical and environmental properties, Nb-Si composites are typically alloyed with Ti and Cr, and Mo-Si-B composites are alloyed with Ti. Phase diagrams of Nb-Cr-Ti-Si and Mo-Si-B-Ti, as prerequisite knowledge for advanced materials design and processing development, are critically needed. The phase diagrams in the metal-rich regions of multicomponent Nb-Cr-Ti-Si and Mo-Si-B-Ti were rapidly established using the Calphad(Calculation of phase diagram) approach coupled with key experiments. The calculated isotherms, isopleths, and solidification paths were validated by experimental work. The important heterogeneous multiphase equilibria in both quaternary systems identified will offer engineers the opportunity to develop materials with a balance of properties for high-temperature applications.

  1. High Strength and Wear Resistant Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    In this paper, a new high strength and wear resistant aluminum cast alloy invented by NASA-MSFC for high temperature applications will be presented. Developed to meet U.S. automotive legislation requiring low-exhaust emission, the novel NASA 398 aluminum-silicon alloy offers dramatic improvement in tensile and fatigue strengths at elevated temperatures (500 F-800 F), enabling new pistons to utilize less material, which can lead to reducing part weight and cost as well as improving performance. NASA 398 alloy also offers greater wear resistance, surface hardness, dimensional stability, and lower thermal expansion compared to conventional aluminum alloys for several commercial and automotive applications. The new alloy can be produced economically using permanent steel molds from conventional gravity casting or sand casting. The technology was developed to stimulate the development of commercial aluminum casting products from NASA-developed technology by offering companies the opportunity to license this technology.

  2. Development, characterization, and applications of high temperature superconductor nanobridge Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Wendt, J.R.; Tigges, C.P.; Hietala, V.M.; Plut, T.A. [Sandia National Labs., Albuquerque, NM (United States); Martens, J.S.; Char, K.; Johansson, M.E. [Conductus, Inc., Sunnyvale, CA (United States)

    1994-03-01

    A well-controlled, high-yield Josephson junction process in high temperature superconductors (HTS) is necessary for the demonstration of ultra-high-speed devices and circuits which exceed the capabilities of conventional electronics. The authors developed nanobridge Josephson junctions in high quality thin-film YBaCuO with dimensions below 100 nm fabricated using electron-beam nanolithography. They characterized this Josephson junction technology for process yield, junction parameter uniformity, and overall applicability for use in high-performance circuits. To facilitate the determination of junction parameters, they developed a measurement technique based on spectral analysis in the range of 90--160 GHz of phase-locked, oscillating arrays of up to 2,450 Josephson junctions. Because of the excellent yield and uniformity of the nanobridge junctions, they successfully applied the junction technology to a wide variety of circuits. These circuits included transmission-line pulse formers and 32 and 64-bit shift registers. The 32-bit shift register was shown to operate at clock speeds near 100 GHz and is believed to be one of the faster and more complex digital circuit demonstrated to date using high temperature superconductor technology.

  3. High Energy Density and High Temperature Multilayer Capacitor Films for Electric Vehicle Applications

    Science.gov (United States)

    Treufeld, Imre; Song, Michelle; Zhu, Lei; Baer, Eric; Snyder, Joe; Langhe, Deepak

    2015-03-01

    Multilayer films (MLFs) with high energy density and high temperature capability (>120 °C) have been developed at Case Western Reserve University. Such films offer a potential solution for electric car DC-link capacitors, where high ripple currents and high temperature tolerance are required. The current state-of-the-art capacitors used in electric cars for converting DC to AC use biaxially oriented polypropylene (BOPP), which can only operate at temperatures up to 85 °C requiring an external cooling system. The polycarbonate (PC)/poly(vinylidene fluoride) (PVDF) MLFs have a higher permittivity compared to that of BOPP (2.3), leading to higher energy density. They have good mechanical stability and reasonably low dielectric losses at 120 °C. Nonetheless, our preliminary dielectric measurements show that the MLFs exhibit appreciable dielectric losses (20%) at 120 °C, which would, despite all the other advantages, make them not suitable for practical applications. Our preliminary data showed that dielectric losses of the MLFs at 120 °C up to 400 MV/m and 1000 Hz originate mostly from impurity ionic conduction. This work is supported by the NSF PFI/BIC Program (IIP-1237708).

  4. Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

    Energy Technology Data Exchange (ETDEWEB)

    Stechel, Ellen Beth; Ambrosini, Andrea; Hall, Aaron Christopher; Lambert, Timothy L.; Staiger, Chad Lynn; Bencomo, Marlene

    2010-09-01

    Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications.

  5. Pt-Al2O3 nanocoatings for high temperature concentrated solar thermal power applications

    Science.gov (United States)

    Nuru, Zebib. Y.; Arendse, C. J.; Nemutudi, R.; Nemraoui, O.; Maaza, M.

    2012-05-01

    Nano-phased structures based on metal-dielectric composites, also called cermets (ceramic-metal), are considered among the most effective spectral selective solar absorbers. For high temperature applications (stable up to 650 °C) noble metal nanoparticles and refractory oxide host matrices are ideal as per their high temperature chemical inertness and stability: Pt/Al2O3 cermet nano-composites are a representative family. This contribution reports on the optical properties of Pt/Al2O3 cermet nano-composites deposited in a multilayered tandem structure. The radio-frequency sputtering optimized Pt/Al2O3 solar absorbers consist of stainless steel substrate/ Mo coating layer/ Pt-Al2O3/ protective Al2O3 layer and stainless steel substrate/ Mo coating layer /Pt-Al2O3 for different composition and thickness of the Pt-Al2O3 cermet coatings. The microstructure, morphology, theoretical modeling and optical properties of the coatings were analyzed by the x-ray diffraction, atomic force, microscopy, effective medium approximation and UV-vis specular and diffuse reflectance.

  6. High Temperature Superconducting Magnets: Revolutionizing Next Generation Accelerators and Other Applications (466th Brookhaven Lecture)

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ramesh (BNL Superconducting Magnet Division)

    2011-02-16

    BNL has always been a leader in the world of superconducting magnets, which are essential to the great modern ccelerators such as the Relativistic Heavy Ion Collider at BNL, or the Large Hadron Collider at CERN, Switzerland. These magnets are made of material that, cooled to 4 Kelvins (K) (-452° Farenheit) become superconducting, that is, lose essentially all resistance to electricity. For the past decade, however, Lab researchers have been exploring the use of new materials that become superconducting at higher temperatures. These materials can operate at the relatively high temperature of 77 K (-351°F), allowing them to be cooled by cheap, plentiful liquid nitrogen, rather than helium, and can create very high magnetic fields. Now far in the lead of this area of research, BNL scientists are exploring avenues for high temperature superconducting magnets that are energy efficient and have magnetic fields that are a million times stronger than the Earth’s. If successful, these new magnets could potentially revolutionize usage in future accelerators, play a key role in energy efficiency and storage, and make possible new applications such as muon colliders and MRI screening in remote areas.

  7. Improved modeling techniques for turbomachinery flow fields

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarayana, B. [Pennsylvania State Univ., University Park, PA (United States); Fagan, J.R. Jr. [Allison Engine Company, Indianapolis, IN (United States)

    1995-10-01

    This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbo-machinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tensor. Penn State will lead the effort to make direct measurements of the momentum and thermal mixing stress tensors in high-speed multistage compressor flow field in the turbomachinery laboratory at Penn State. They will also process the data by both conventional and conditional spectrum analysis to derive momentum and thermal mixing stress tensors due to blade-to-blade periodic and aperiodic components, revolution periodic and aperiodic components arising from various blade rows and non-deterministic (which includes random components) correlations. The modeling results from this program will be publicly available and generally applicable to steady-state Navier-Stokes solvers used for turbomachinery component (compressor or turbine) flow field predictions. These models will lead to improved methodology, including loss and efficiency prediction, for the design of high-efficiency turbomachinery and drastically reduce the time required for the design and development cycle of turbomachinery.

  8. High temperature superconductor bulk materials fundamentals, processing, properties control, applications aspects

    CERN Document Server

    Krabbes, Gernot; Canders, Wolf-Rüdiger; May, Hardo; Palka, Ryszard

    2005-01-01

    With its comprehensive review of the current knowledge and the future requirements in the field, this book presents all the features of bulk high temperature superconducting materials. Starting from physical and chemical fundamentals, the authors move on to portray methods and problems of materials processing, thoroughly working out the characteristic properties of bulk superconductors in contrast to long conductors and films. They provide a wide range of specific materials characteristics with respect to the latest developments and future applications guiding from fundamentals to practical engineering examples. The authors are all leading international specialists involved in the field of high TC superconductor bulk materials since the beginning. Of utmost interest to engineers, scientists, and PhD students working in this field

  9. High-temperature superconducting current leads for micro-SMES application

    Science.gov (United States)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Buckles, W. E.; Daugherty, M. A.; Weber, B. R.

    1994-07-01

    SMES is being applied on a microscale (1-10 MJ stored energy) to improve electrical power quality. A major portion of the SMES refrigeration load is for cooling the conventional (copper, vapor-cooled) current leads that transfer energy between the magnet and the power-conditioning equipment. The lead refrigeration load can be reduced significantly by the use of high-temperature superconductors (HTSs). An HTS current lead suitable for micro-SMES application has been designed. The lower stage of the lead employs HTSs. A transition between the lower stage and the conventional upper-stage lead is heat-intercepted by a cryocooler. Details of the design are presented. Construction and operating experiences are discussed.

  10. Thermographic Phosphors for High Temperature Measurements: Principles, Current State of the Art and Recent Applications

    Directory of Open Access Journals (Sweden)

    Konstantinos Kontis

    2008-09-01

    Full Text Available This paper reviews the state of phosphor thermometry, focusing on developments in the past 15 years. The fundamental principles and theory are presented, and the various spectral and temporal modes, including the lifetime decay, rise time and intensity ratio, are discussed. The entire phosphor measurement system, including relative advantages to conventional methods, choice of phosphors, bonding techniques, excitation sources and emission detection, is reviewed. Special attention is given to issues that may arise at high temperatures. A number of recent developments and applications are surveyed, with examples including: measurements in engines, hypersonic wind tunnel experiments, pyrolysis studies and droplet/spray/gas temperature determination. They show the technique is flexible and successful in measuring temperatures where conventional methods may prove to be unsuitable.

  11. Cross-linked aromatic cationic polymer electrolytes with enhanced stability for high temperature fuel cell applications

    DEFF Research Database (Denmark)

    Ma, Wenjia; Zhao, Chengji; Yang, Jingshuai

    2012-01-01

    Diamine-cross-linked membranes were prepared from cross-linkable poly(arylene ether ketone) containing pendant cationic quaternary ammonium group (QPAEK) solution by a facile and general thermal curing method using 4,4′-diaminodiphenylmethane with rigid framework and 1,6-diaminohexane with flexible...... framework as cross-linker, respectively. Self-cross-linked cationic polymer electrolytes membranes were also prepared for comparison. The diamines were advantageously distributed within the polymeric matrix and its amine function groups interacted with the benzyl bromide of QPAEK, resulting in a double...... that the diamine-cross-linked membranes using the rigid cross-linker show much improved properties than that using the flexible cross-linker. More properties relating to the feasibility in high temperature proton exchange membrane fuel cell applications were investigated in detail....

  12. Nonimaging solar thermal collector for high temperature terrestrial and space applications

    Science.gov (United States)

    Mouzouris, Michael; Brooks, Michael J.

    2009-08-01

    A point-focus solar concentrator is described for use in high temperature terrestrial and space applications. The system comprises a nonimaging reflective lens in the form of a ring array concentrator coupled to a fiber optic bundle through which the concentrated light is transmitted. Unlike mirror-based systems, the concentrator is a ring array composed of concentrically nested elements focusing energy to the rear of the structure. Energy is transported from the concentrator by optical fibers and directed at a target where high heat flux is needed. The fiber optic bundle is tailored for solar energy transmission and includes a fused end to minimize inter-fiber losses at the injection point. The integrated system is intended to produce concentrated thermal energy without the need for electricity intensive heating elements. Optical efficiency is investigated through a ray trace analysis.

  13. Nano-structured alloy and composite coatings for high temperature applications

    Directory of Open Access Journals (Sweden)

    Wei Gao

    2004-03-01

    Full Text Available Nano-structured materials often possess special properties that materials with identical compositions but ordinary grain size do not have. This paper reports our work on the surface nano-crystallisation and nano-structured alloy and composite coatings. A number of processing methods including magnetron sputtering, thermal spray and pulse electro-spark deposition have been used to produce surface nano-crystalline structure. The compositions and microstructures can be well controlled by using different targets or electrodes, nano-structured composites and adjusting processing parameters. Surface nano-structured coatings can provide special chemical, mechanical and electronic properties such as high temperature corrosion and corrosive wear resistance. It has potential applications such as turbine blades, engine parts for petrochemical, aerospace and electronic device industries. This paper is focused on the study of the interrelations between processing, microstructure and properties. Physical models have been established to explain the effects of nano-crystalline structure on the properties.

  14. Grids for Applications in High-Temperature High-Resolution Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Yucheng Lan

    2010-01-01

    Full Text Available New TEM grids coated with ultrathin amorphous Al2O3 films have been developed using atomic layer deposition technique. The amorphous Al2O3 films can withstand temperatures over 600∘C in air and 900∘C in vacuum when the thickness of the Al2O3 film is 2 nm, and up to 1000∘C in air when the thickness is 25 nm, which makes heating TEM grids with nanoparticles up to 1000∘C in air and immediate TEM observation without interrupting the nanoparticles possible. Such coated TEM grids are very much desired for applications in high-temperature high-resolution transmission electron microscopy.

  15. GRCop-84: A High Temperature Copper-based Alloy For High Heat Flux Applications

    Science.gov (United States)

    Ellis, David L.

    2005-01-01

    While designed for rocket engine main combustion chamber liners, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) offers potential for high heat flux applications in industrial applications requiring a temperature capability up to approximately 700 C (1292 F). GRCop-84 is a copper-based alloy with excellent elevated temperature strength, good creep resistance, long LCF lives and enhanced oxidation resistance. It also has a lower thermal expansion than copper and many other low alloy copper-based alloys. GRCop-84 can be manufactured into a variety of shapes such as tubing, bar, plate and sheet using standard production techniques and requires no special production techniques. GRCop-84 forms well, so conventional fabrication methods including stamping and bending can be used. GRCop-84 has demonstrated an ability to be friction stir welded, brazed, inertia welded, diffusion bonded and electron beam welded for joining to itself and other materials. Potential applications include plastic injection molds, resistance welding electrodes and holders, permanent metal casting molds, vacuum plasma spray nozzles and high temperature heat exchanger applications.

  16. Recovery Act: High-Temperature Circuit Boards for use in Geothermal Well Monitoring Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hooker, Matthew [Composite Tehcnology Development, Inc., Lafayette, CO (United States); Fabian, Paul [Composite Tehcnology Development, Inc., Lafayette, CO (United States)

    2013-05-01

    The U.S. Department of Energy is leading the development of alternative energy sources that will ensure the long-term energy independence of our nation. One of the key renewable resources currently being advanced is geothermal energy. To tap into the large potential offered by generating power from the heat of the earth, and for geothermal energy to be more widely used, it will be necessary to drill deeper wells to reach the hot, dry rock located up to 10 km beneath the earth’s surface. In this instance, water will be introduced into the well to create a geothermal reservoir. A geothermal well produced in this manner is referred to as an enhanced geothermal system (EGS). EGS reservoirs are typically at depths of 3 to 10 km, and the temperatures at these depths have become a limiting factor in the application of existing downhole technologies. These high temperatures are especially problematic for electronic systems such as downhole data-logging tools, which are used to map and characterize the fractures and high-permeability regions in underground formations. Information provided by these tools is assessed so that underground formations capable of providing geothermal energy can be identified, and the subsequent drilling operations can be accurately directed to those locations. The mapping of geothermal resources involves the design and fabrication of sensor packages, including the electronic control modules, to quantify downhole conditions (300°C temperature, high pressure, seismic activity, etc.). Because of the extreme depths at which these measurements are performed, it is most desirable to perform the sensor signal processing downhole and then transmit the information to the surface. This approach necessitates the use of high-temperature electronics that can operate in the downhole environment. Downhole signal processing in EGS wells will require the development and demonstration of circuit boards that can withstand the elevated temperatures found at these

  17. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, F.D.; Elshabini, A.

    2006-11-30

    cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE) [2]. This change would reduce the complexity of the cooling system which currently relies on two loops to a single loop [3]. However, the current nominal coolant temperature entering these inverters is 65 C [3], whereas a normal ICE coolant temperature would be much higher at approximately 100 C. This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. With this change in mind, significant progress has been made on the use of SiC devices for inverters that can withstand much higher junction temperatures than traditional Si based inverters [4,5,6]. However, a key problem which the single coolant loop and high temperature devices is the effective packaging of these devices and related components into a high temperature inverter. The elevated junction temperatures that exist in these modules are not compatible with reliable inverters based on existing packaging technology. This report seeks to provide a literature survey of high temperature packaging and to highlight the issues related to the implementation of high temperature power electronic modules for HEV and PHEV applications. For purposes of discussion, it will be assumed in this report that 200 C is the targeted maximum junction temperature.

  18. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, F.D.; Elshabini, A.

    2006-11-30

    cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE) [2]. This change would reduce the complexity of the cooling system which currently relies on two loops to a single loop [3]. However, the current nominal coolant temperature entering these inverters is 65 C [3], whereas a normal ICE coolant temperature would be much higher at approximately 100 C. This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. With this change in mind, significant progress has been made on the use of SiC devices for inverters that can withstand much higher junction temperatures than traditional Si based inverters [4,5,6]. However, a key problem which the single coolant loop and high temperature devices is the effective packaging of these devices and related components into a high temperature inverter. The elevated junction temperatures that exist in these modules are not compatible with reliable inverters based on existing packaging technology. This report seeks to provide a literature survey of high temperature packaging and to highlight the issues related to the implementation of high temperature power electronic modules for HEV and PHEV applications. For purposes of discussion, it will be assumed in this report that 200 C is the targeted maximum junction temperature.

  19. SiC Matrix Composites for High Temperature Hypersonic Vehicle Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Durable high temperature materials are required for reusable hypersonic structural thermal protection systems. In particular, temperatures exceeding 2700:F, and...

  20. SiC Matrix Composites for High Temperature Hypersonic Vehicle Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Durable high temperature materials are required for hypersonic engine and structural thermal protection systems. In particular, 2700:F or greater capable structural...

  1. Analytical modeling of helium turbomachinery using FORTRAN 77

    Science.gov (United States)

    Balaji, Purushotham

    Advanced Generation IV modular reactors, including Very High Temperature Reactors (VHTRs), utilize helium as the working fluid, with a potential for high efficiency power production utilizing helium turbomachinery. Helium is chemically inert and nonradioactive which makes the gas ideal for a nuclear power-plant environment where radioactive leaks are a high concern. These properties of helium gas helps to increase the safety features as well as to decrease the aging process of plant components. The lack of sufficient helium turbomachinery data has made it difficult to study the vital role played by the gas turbine components of these VHTR powered cycles. Therefore, this research work focuses on predicting the performance of helium compressors. A FORTRAN77 program is developed to simulate helium compressor operation, including surge line prediction. The resulting design point and off design performance data can be used to develop compressor map files readable by Numerical Propulsion Simulation Software (NPSS). This multi-physics simulation software that was developed for propulsion system analysis has found applications in simulating power-plant cycles.

  2. Barriers to the Application of High-Temperature Coolants in Hybrid Electric Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Staunton, Robert H [ORNL; Hsu, John S [ORNL; Starke, Michael R [ORNL

    2006-09-01

    This study was performed by the Oak Ridge National Laboratory (ORNL) to identify practical approaches, technical barriers, and cost impacts to achieving high-temperature coolant operation for certain traction drive subassemblies and components of hybrid electric vehicles (HEV). HEVs are unique in their need for the cooling of certain dedicated-traction drive subassemblies/components that include the electric motor(s), generators(s), inverter, dc converter (where applicable), and dc-link capacitors. The new coolant system under study would abandon the dedicated 65 C coolant loop, such as used in the Prius, and instead rely on the 105 C engine cooling loop. This assessment is important because automotive manufacturers are interested in utilizing the existing water/glycol engine cooling loop to cool the HEV subassemblies in order to eliminate an additional coolant loop with its associated reliability, space, and cost requirements. In addition, the cooling of power electronic devices, traction motors, and generators is critical in meeting the U.S. Department of Energy (DOE) FreedomCAR and Vehicle Technology (FCVT) goals for power rating, volume, weight, efficiency, reliability, and cost. All of these have been addressed in this study. Because there is high interest by the original equipment manufacturers (OEMs) in reducing manufacturing cost to enhance their competitive standing, the approach taken in this analysis was designed to be a positive 'can-do' approach that would be most successful in demonstrating the potential or opportunity of relying entirely on a high-temperature coolant system. Nevertheless, it proved to be clearly evident that a few formidable technical and cost barriers exist and no effective approach for mitigating the barriers was evident in the near term. Based on comprehensive thermal tests of the Prius reported by ORNL in 2005 [1], the continuous ratings at base speed (1200 rpm) with different coolant temperatures were projected from

  3. Barriers to the Application of High-Temperature Coolants in Hybrid Electric Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, J.S.; Staunton, M.R.; Starke, M.R.

    2006-09-30

    This study was performed by the Oak Ridge National Laboratory (ORNL) to identify practical approaches, technical barriers, and cost impacts to achieving high-temperature coolant operation for certain traction drive subassemblies and components of hybrid electric vehicles (HEV). HEVs are unique in their need for the cooling of certain dedicated-traction drive subassemblies/components that include the electric motor(s), generators(s), inverter, dc converter (where applicable), and dc-link capacitors. The new coolant system under study would abandon the dedicated 65 C coolant loop, such as used in the Prius, and instead rely on the 105 C engine cooling loop. This assessment is important because automotive manufacturers are interested in utilizing the existing water/glycol engine cooling loop to cool the HEV subassemblies in order to eliminate an additional coolant loop with its associated reliability, space, and cost requirements. In addition, the cooling of power electronic devices, traction motors, and generators is critical in meeting the U.S. Department of Energy (DOE) FreedomCAR and Vehicle Technology (FCVT) goals for power rating, volume, weight, efficiency, reliability, and cost. All of these have been addressed in this study. Because there is high interest by the original equipment manufacturers (OEMs) in reducing manufacturing cost to enhance their competitive standing, the approach taken in this analysis was designed to be a positive 'can-do' approach that would be most successful in demonstrating the potential or opportunity of relying entirely on a high-temperature coolant system. Nevertheless, it proved to be clearly evident that a few formidable technical and cost barriers exist and no effective approach for mitigating the barriers was evident in the near term. Based on comprehensive thermal tests of the Prius reported by ORNL in 2005 [1], the continuous ratings at base speed (1200 rpm) with different coolant temperatures were projected from

  4. High-temperature superconductor current leads for electric utility SMES applications

    Science.gov (United States)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Buckles, W. E.; Weber, B. R.; Dixon, K. D.; Rey, C. M.

    Current leads that utilize high-temperature superconductors (HTSS) to deliver power to devices operating at liquid helium temperature have the potential to reduce refrigeration requirements to levels significantly below those achievable with conventional leads. As part of the US Department of Energy's Superconductivity Technology Program, Argonne National Laboratory and two industrial partners are developing HTS current leads for application to superconducting magnetic energy storage (SMES) systems. Superconductivity, Inc. (SI) is a supplier of micro-SMES systems for power-quality applications. A typical SI SMES system has an 0.3-kWh energy capacity and operates at currents up to 1.2 kA. The Babcock & Wilcox Company (B&W) is engaged in a project to design, build, and demonstrate a midsized SMES system. The B&W system has an 0.5-MWh energy capacity and operates at currents up to 16 kA. Details of the lead designs, including materials, configuration, and performance predictions, are presented.

  5. Trimethylsilylcyclopentadiene as a novel electrolyte additive for high temperature application of lithium nickel manganese oxide cathode

    Science.gov (United States)

    Tu, Wenqiang; Ye, Changchun; Yang, Xuerui; Xing, Lidan; Liao, Youhao; Liu, Xiang; Li, Weishan

    2017-10-01

    Electrolyte additives are necessary for the application of high potential cathode in high energy density lithium ion batteries, especially at elevated temperature. However, the electrolyte additives that can effectively suppress the dissolution of transition metal ions from cathode have seldom been developed up to date. In this work, we propose a novel electrolyte additive, trimethylsilylcyclopentadiene (SE), for high temperature application of a representative high potential cathode, lithium nickel manganese oxide (LiNi0.5Mn1.5O4). It is found that the dissolution of Mn and Ni from LiNi0.5Mn1.5O4 can be effectively suppressed by applying SE. With applying 0.25% SE, the dissolved amount of Mn and Ni is decreased by 97.4% and 98%, respectively, after 100 cycles at 55 °C. Correspondingly, the cyclic performance of LiNi0.5Mn1.5O4 is significantly improved. Physical characterizations and electrochemical measurements show that SE can be preferentially oxidized and generate a protective film on LiNi0.5Mn1.5O4. The resulting film inhibits the electrolyte decomposition and the transition metal ion dissolution.

  6. Numerical simulation of a high temperature thermal storage unit for solar gas turbine applications

    CSIR Research Space (South Africa)

    Klein, P

    2010-09-01

    Full Text Available cycles, in the form of molten salts and thermal oil reservoirs, the high temperature nature (>800°C) of Brayton cycles requires a different approach. One solution is to make use of a high temperature packed bed. The transient heating and cooling of a...

  7. High Temperature, Controlled-Atmosphere Aerodynamic Levitation Experiments with Applications in Planetary Science

    Science.gov (United States)

    Macris, C. A.; Badro, J.; Eiler, J. M.; Stolper, E. M.

    2016-12-01

    The aerodynamic levitation laser apparatus is an instrument in which spherical samples are freely floated on top of a stream of gas while being heated with a CO2laser to temperatures up to about 3500 °C. Laser heated samples, ranging in size from 0.5 to 3.5 mm diameter, can be levitated in a variety of chemically active or inert atmospheres in a gas-mixing chamber (e.g., Hennet et al. 2006; Pack et al. 2010). This allows for containerless, controlled-atmosphere, high temperature experiments with potential for applications in earth and planetary science. A relatively new technique, aerodynamic levitation has been used mostly for studies of the physical properties of liquids at high temperatures (Kohara et al. 2011), crystallization behavior of silicates and oxides (Arai et al. 2004), and to prepare glasses from compositions known to crystallize upon quenching (Tangeman et al. 2001). More recently, however, aerodynamic levitation with laser heating has been used as an experimental technique to simulate planetary processes. Pack et al. (2010) used levitation and melting experiments to simulate chondrule formation by using Ar-H2 as the flow gas, thus imposing a reducing atmosphere, resulting in reduction of FeO, Fe2O3, and NiO to metal alloys. Macris et al. (2015) used laser heating with aerodynamic levitation to reproduce the textures and diffusion profiles of major and minor elements observed in impact ejecta from the Australasian strewn field, by melting a powdered natural tektite mixed with 60-100 μm quartz grains on a flow of pure Ar gas. These experiments resulted in quantitative modeling of Si and Al diffusion, which allowed for interpretations regarding the thermal histories of natural tektites and their interactions with the surrounding impact vapor plume. Future experiments will employ gas mixing (CO, CO2, H2, O, Ar) in a controlled atmosphere levitation chamber to explore the range of fO2applicable to melt-forming impacts on other rocky planetary bodies

  8. Fluid mechanics and thermodynamics of turbomachinery

    CERN Document Server

    Dixon, S Larry

    2005-01-01

    The new edition will continue to be of use to engineers in industry and technological establishments, especially as brief reviews are included on many important aspects of Turbomachinery, giving pointers towards more advanced sources of information. For readers looking towards the wider reaches of the subject area, very useful additional reading is referenced in the bibliography. The subject of Turbomachinery is in continual review, and while the basics do not change, research can lead to refinements in popular methods, and new data can emerge. This book has applications for professiona

  9. High-Temperature Superconductivity

    Science.gov (United States)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  10. Ceramic matrix composite applications in advanced liquid fuel rocket engine turbomachinery

    Science.gov (United States)

    Brockmeyer, Jerry W.

    1992-01-01

    Fiber-reinforced ceramic matrix composites have been identified with properties suitable for near term applications. Conceptual design studies indicate the feasibility of applying C/SiC, and subelements were manufactured that verify selected fabrication features and key material properties. Tests and inspection of these subelements confirmed their capabilities.

  11. Efficient PCA-driven EAs and metamodel-assisted EAs, with applications in turbomachinery

    Science.gov (United States)

    Kyriacou, Stylianos A.; Asouti, Varvara G.; Giannakoglou, Kyriakos C.

    2014-07-01

    This article presents methods to enhance the efficiency of Evolutionary Algorithms (EAs), particularly those assisted by surrogate evaluation models or metamodels. The gain in efficiency becomes important in applications related to industrial optimization problems with a great number of design variables. The development is based on the principal components analysis of the elite members of the evolving EA population, the outcome of which is used to guide the application of evolution operators and/or train dependable metamodels/artificial neural networks by reducing the number of sensory units. Regarding the latter, the metamodels are trained with less computing cost and yield more relevant objective function predictions. The proposed methods are applied to constrained, single- and two-objective optimization of thermal and hydraulic turbomachines.

  12. High temperature radiator materials for applications in the low Earth orbital environment

    Science.gov (United States)

    Rutledge, Sharon K.; Banks, Bruce A.; Mirtich, Michael J.; Lebed, Richard; Brady, Joyce; Hotes, Deborah; Kussmaul, Michael

    1987-01-01

    Radiators must be constructed of materials which have high emittance in order to efficiently radiate heat from high temperature space power systems. In addition, if these radiators are to be used for applications in the low Earth orbital environment, they must not be detrimentally affected by exposure to atomic oxygen. Four materials selected as candidate radiator materials (304 stainless steel, copper, titanium-6% aluminum-4% vanadium (Ti-6%Al-4%V), and niobium-1% zirconium (Nb-1%Zr)) were surface modified by acid etching, heat treating, abrading, sputter texturing, electrochemical etching, and combinations of the above in order to improve their emittance. Combination treatment techniques with heat treating as the second treatment provided about a factor of two improvement in emittance for 304 stainless steel, Ti-6%Al-4%V, and Nb-1%Zr. A factor of three improvement in emittance occurred for discharge chamber sputter textured copper. Exposure to atomic oxygen in an RF plasma asher did not significantly change the emittance of those samples that had been heat treated as part of their texturing process. An evaluation of oxygen penetration is needed to understand how oxidation affects the mechanical properties of these materials when heat treated.

  13. Construction Of A Piezoelectric-Based Resonance Ceramic Pressure Sensor Designed For High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Belavič Darko

    2015-09-01

    Full Text Available In this work the design aspects of a piezoelectric-based resonance ceramic pressure sensor made using low-temperature co-fired ceramic (LTCC technology and designed for high-temperature applications is presented. The basic pressure-sensor structure consists of a circular, edge-clamped, deformable diaphragm that is bonded to a ring, which is part of the rigid ceramic structure. The resonance pressure sensor has an additional element – a piezoelectric actuator – for stimulating oscillation of the diaphragm in the resonance-frequency mode. The natural resonance frequency is dependent on the diaphragm construction (i.e., its materials and geometry and on the actuator. This resonance frequency then changes due to the static deflection of the diaphragm caused by the applied pressure. The frequency shift is used as the output signal of the piezoelectric resonance pressure sensor and makes it possible to measure the static pressure. The characteristics of the pressure sensor also depend on the temperature, i.e., the temperature affects both the ceramic structure (its material and geometry and the properties of the actuator. This work is focused on the ceramic structure, while the actuator will be investigated later.

  14. Development of practical high temperature superconducting wire for electric power application

    Science.gov (United States)

    Hawsey, Robert A.; Sokolowski, Robert S.; Haldar, Pradeep; Motowidlo, Leszek R.

    1995-01-01

    The technology of high temperature superconductivity has gone from beyond mere scientific curiousity into the manufacturing environment. Single lengths of multifilamentary wire are now produced that are over 200 meters long and that carry over 13 amperes at 77 K. Short-sample critical current densities approach 5 x 104 A/sq cm at 77 K. Conductor requirements such as high critical current density in a magnetic field, strain-tolerant sheathing materials, and other engineering properties are addressed. A new process for fabricating round BSCCO-2212 wire has produced wires with critical current densities as high as 165,000 A/sq cm at 4.2 K and 53,000 A/sq cm at 40 K. This process eliminates the costly, multiple pressing and rolling steps that are commonly used to develop texture in the wires. New multifilamentary wires with strengthened sheathing materials have shown improved yield strengths up to a factor of five better than those made with pure silver. Many electric power devices require the wire to be formed into coils for production of strong magnetic fields. Requirements for coils and magnets for electric power applications are described.

  15. Hyper-stable organo-Eu(III) luminophore under high temperature for photo-industrial application.

    Science.gov (United States)

    Nakajima, Ayako; Nakanishi, Takayuki; Kitagawa, Yuichi; Seki, Tomohiro; Ito, Hajime; Fushimi, Koji; Hasegawa, Yasuchika

    2016-04-14

    Novel organo-Eu(III) luminophores, Eu(hfa)x(CPO)y and Eu(hfa)x(TCPO)y (hfa: hexafluoroacetylacetonate, CPO: 4-carboxyphenyl diphenyl phosphine oxide, TCPO: 4,4',4″-tricarboxyphenyl phosphine oxide), were synthesized by the complexation of Eu(III) ions with hfa moieties and CPO or TCPO ligands. The thermal and luminescent stabilities of the luminophores are extremely high. The decomposition temperature of Eu(hfa)x(CPO)y and Eu(hfa)x(TCPO)y were determined as 200 and 450 °C, respectively. The luminescence of Eu(hfa)x(TCPO)y under UV light irradiation was observed even at a high temperature, 400 °C. The luminescent properties of Eu(hfa)x(CPO)y and Eu(hfa)x(TCPO)y were estimated from emission spectra, quantum yields and lifetime measurements. The energy transfer efficiency from hfa moieties to Eu(III) ions in Eu(hfa)x(TCPO)y was 59%. The photosensitized luminescence of hyper-stable Eu(hfa)x(TCPO)y at 400 °C is demonstrated for future photonic applications.

  16. Principles of turbomachinery

    CERN Document Server

    Korpela, Seppo A

    2012-01-01

    The text is based on a course on turbomachinery which the author has taught since year 2000 as a technical elective. Topics include; Energy Transfer in Turbomachines, Gas and Steam Turbines, and Hydraulic Turbines. New material on wind turbines, and three-dimensional effects in axial turbomachines is included. The level is kept as such that students can smoothly move from a study of the most successful books in thermodynamics, fluid dynamics, and heat transfer to the subject of turbomachinery. The chapters are organized in such a way that the more difficult material is left to the later sectio

  17. Novel High-Temperature Pressure Sensors for Extreme Service Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I research will result in a prototype high temperature pressure sensing cell based on the piezoresistive properties of platinum:tungsten alloys. The...

  18. Hybrid High-Temperature Superconductor Current Leads for Space Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Tai-Yang Research Company (TYRC) proposes to address the need for high temperature superconducting (HTS) current leads used in an adiabatic demagnetization...

  19. High-Temperature Desulfurization of Heavy Fuel-Derived Reformate Gas Streams for SOFC Applications

    Science.gov (United States)

    Flytzani-Stephanopoulos, Maria; Surgenor, Angela D.

    2007-01-01

    Desulfurization of the hot reformate gas produced by catalytic partial oxidation or autothermal reforming of heavy fuels, such as JP-8 and jet fuels, is required prior to using the gas in a solid oxide fuel cell (SOFC). Development of suitable sorbent materials involves the identification of sorbents with favorable sulfidation equilibria, good kinetics, and high structural stability and regenerability at the SOFC operating temperatures (650 to 800 C). Over the last two decades, a major barrier to the development of regenerable desulfurization sorbents has been the gradual loss of sorbent performance in cyclic sulfidation and regeneration at such high temperatures. Mixed oxide compositions based on ceria were examined in this work as regenerable sorbents in simulated reformate gas mixtures and temperatures greater than 650 C. Regeneration was carried out with dilute oxygen streams. We have shown that under oxidative regeneration conditions, high regeneration space velocities (greater than 80,000 h(sup -1)) can be used to suppress sulfate formation and shorten the total time required for sorbent regeneration. A major finding of this work is that the surface of ceria and lanthanan sorbents can be sulfided and regenerated completely, independent of the underlying bulk sorbent. This is due to reversible adsorption of H2S on the surface of these sorbents even at temperatures as high as 800 C. La-rich cerium oxide formulations are excellent for application to regenerative H2S removal from reformate gas streams at 650 to 800 C. These results create new opportunities for compact sorber/regenerator reactor designs to meet the requirements of solid oxide fuel cell systems at any scale.

  20. First-principles screening of complex transition metal hydrides for high temperature applications.

    Science.gov (United States)

    Nicholson, Kelly M; Sholl, David S

    2014-11-17

    Metal hydrides with enhanced thermodynamic stability with respect to the associated binary hydrides are useful for high temperature applications in which highly stable materials with low hydrogen overpressures are desired. Though several examples of complex transition metal hydrides (CTMHs) with such enhanced stability are known, little thermodynamic or phase stability information is available for this materials class. In this work, we use semiautomated thermodynamic and phase diagram calculations based on density functional theory (DFT) and grand canonical linear programming (GCLP) methods to screen 102 ternary and quaternary CTMHs and 26 ternary saline hydrides in a library of over 260 metals, intermetallics, binary, and higher hydrides to identify materials that release hydrogen at higher temperatures than the associated binary hydrides and at elevated temperatures, T > 1000 K, for 1 bar H2 overpressure. For computational efficiency, we employ a tiered screening approach based first on solid phase ground state energies with temperature effects controlled via H2 gas alone and second on the inclusion of phonon calculations that correct solid phase free energies for temperature-dependent vibrational contributions. We successfully identified 13 candidate CTMHs including Eu2RuH6, Yb2RuH6, Ca2RuH6, Ca2OsH6, Ba2RuH6, Ba3Ir2H12, Li4RhH4, NaPd3H2, Cs2PtH4, K2PtH4, Cs3PtH5, Cs3PdH3, and Rb2PtH4. The most stable CTMHs tend to crystallize in the Sr2RuH6 cubic prototype structure and decompose to the pure elements and hydrogen rather than to intermetallic phases.

  1. GRCop-84: A High-Temperature Copper Alloy for High-Heat-Flux Applications

    Science.gov (United States)

    Ellis, David L.

    2005-01-01

    GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) is a new high-temperature copper-based alloy. It possesses excellent high-temperature strength, creep resistance and low-cycle fatigue up to 700 C (1292 F) along with low thermal expansion and good conductivity. GRCop-84 can be processed and joined by a variety of methods such as extrusion, rolling, bending, stamping, brazing, friction stir welding, and electron beam welding. Considerable mechanical property data has been generated for as-produced material and following simulated braze cycles. The data shows that the alloy is extremely stable during thermal exposures. This paper reviews the major GRCop-84 mechanical and thermophysical properties and compares them to literature values for a variety of other high-temperature copper-based alloys.

  2. The 1992 NASA Langley Measurement Technology Conference: Measurement Technology for Aerospace Applications in High-Temperature Environments

    Science.gov (United States)

    Singh, Jag J. (Editor); Antcliff, Richard R. (Editor)

    1992-01-01

    An intensive 2-day conference to discuss the current status of measurement technology in the areas of temperature/heat flux, stress/strain, pressure, and flowfield diagnostics for high temperature aerospace applications was held at Langley Research Center, Hampton, Virginia, on April 22 and 23, 1993. Complete texts of the papers presented at the Conference are included in these proceedings.

  3. Optimization of a High Temperature PEMFC micro-CHP System by Formulation and Application of a Process Integration Methodology

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2013-01-01

    A 1 kWe micro combined heat and power (CHP) system based on high temperature proton exchange membrane fuel cell (PEMFC) technology is modeled and optimized by formulation and application of a process integration methodology. The system can provide heat and electricity for a singlefamily household...

  4. Experimental High Temperature Characterization of a Magnetic Bearing for Turbomachinery

    Science.gov (United States)

    Montague, Gerald; Jansen, Mark; Provenza, Andrew; Palazzolo, Alan; Jansen, Ralph; Ebihara, Ben

    2003-01-01

    Open loop, experimental force and power measurements of a radial, redundant-axis, magnetic bearing at temperatures to 1000 F (538 C) and rotor speeds to 15,000 RPM along with theoretical temperature and force models are presented in this paper. The experimentally measured force produced by a single C-core using 22A was 600 lb. (2.67 kN) at room temperature and 380 lb. (1.69 kN) at 1000 F (538 C). These values were compared with force predictions based on a 1D magnetic circuit analysis and a thermal analysis of gap growth as a function of temperature. Tests under rotating conditions showed that rotor speed has a negligible effect on the bearing s load capacity. One C-core required approximately 340 W of power to generate 190 lb. (8.45 kN) of magnetic force at 1000 F (538 C); however the magnetic air gap was much larger than at room temperature. The data presented is after the bearing had already operated six thermal cycles and eleven total (not consecutive) hours at 1000 F (538 C).

  5. High-Temperature, Lightweight, Self-Healing Ceramic Composites for Aircraft Engine Applications

    Science.gov (United States)

    Raj, Sai V.; Bhatt, Ramkrishna

    2013-01-01

    The use of reliable, high-temperature, lightweight materials in the manufacture of aircraft engines is expected to result in lower fossil and biofuel consumption, thereby leading to cost savings and lower carbon emissions due to air travel. Although nickel-based superalloy blades and vanes have been successfully used in aircraft engines for several decades, there has been an increased effort to develop high-temperature, lightweight, creep-resistant substitute materials under various NASA programs over the last two decades. As a result, there has been a great deal of interest in developing SiC/SiC ceramic matrix composites (CMCs) due to their higher damage tolerance compared to monolithic ceramics. Current-generation SiC/SiC ceramic matrix composites rely almost entirely on the SiC fibers to carry the load, owing to the premature cracking of the matrix during loading. Thus, the high-temperature usefulness of these CMCs falls well below their theoretical capabilities. The objective of this work is to develop a new class of high-temperature, lightweight, self-healing, SiC fiber-reinforced, engineered matrix ceramic composites.

  6. Ultra-High Temperature Metallic Seal/Energizer Development for Aero Propulsion and Gas Turbine Applications

    Science.gov (United States)

    Cornett, Ken; Newman, Jesse; Datta, Amit

    2009-01-01

    The industry is requiring seals to operate at higher and higher temperatures. Traditional static seal designs and materials experience stress relaxation, losing their ability to maintain contact with moving flanges. Ultra High Temperature seal development program is a multiphase program with incremental increases in seal operating temperatures.

  7. Insulation development for high-temperature batteries for electric vehicle application. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-12-01

    The objective of this contract is to develop and demonstrate a high performance, vacuum insulation which is capable of withstanding 15 psi plus battery loading with low compression operating in the 660 to 840/sup 0/F range. The developed insulation would allow construction of rectangular, lightweight and low-cost, vacuum-insulated enclosures for electric vehicles using Na/S or Li/MS batteries. The goals of the program are to develop a vacuum insulation with the following properties: thermal conductivity 140 x 10/sup -5/ Btu/h-ft/sup 0/F, density, 18 lbs/ft/sup 3/ and compression 10% from 0 to 15 psi load. A new milestone in high-temperature, load-bearing, preformed insulation was achieved. The two insulation systems demonstrated to-date have exceeded the goals of the program. Pegged Multi-Foil system has a measured conductivity of 100 x 10/sup -5/ Btu/h-ft/sup 0/F between 840 and 75/sup 0/F, density 11 lbs/ft/sup 3/ and compression of 10%. The second system which exceeded the goals of the program is a Linde Multi-Foil inslation with discrete load-carrying support areas. It has a measured thermal conductivity of 95 x 10/sup -5/ Btu/h-ft/sup 0/F, a density of 15 lbs/ft/sup 3/ and a compression of 21%. A third inslation is a continuous support, load-bearing board system. Although the thermal conductivity and density are above the goal of the program, the system is very practical and may be used in specialized applications; i.e., forklift trucks. The best load-bearing board insulation system developed to-date has a conductivity of 224 x 10/sup -5/ Btu/hr-ft/sup 0/F, a density of 22 lbs/ft/sup 3/ and a compression of 7%. It is believed that the new insulation systems need further development in order to establish their long-term stability, handleability and cost-effective production.

  8. Heat treated 9 Cr-1 Mo steel material for high temperature application

    Science.gov (United States)

    Jablonski, Paul D.; Alman, David; Dogan, Omer; Holcomb, Gordon; Cowen, Christopher

    2012-08-21

    The invention relates to a composition and heat treatment for a high-temperature, titanium alloyed, 9 Cr-1 Mo steel exhibiting improved creep strength and oxidation resistance at service temperatures up to 650.degree. C. The novel combination of composition and heat treatment produces a heat treated material containing both large primary titanium carbides and small secondary titanium carbides. The primary titanium carbides contribute to creep strength while the secondary titanium carbides act to maintain a higher level of chromium in the finished steel for increased oxidation resistance, and strengthen the steel by impeding the movement of dislocations through the crystal structure. The heat treated material provides improved performance at comparable cost to commonly used high-temperature steels such as ASTM P91 and ASTM P92, and requires heat treatment consisting solely of austenization, rapid cooling, tempering, and final cooling, avoiding the need for any hot-working in the austenite temperature range.

  9. High temperature oxidation behavior of ODS iron-base alloys for nuclear energy application

    Energy Technology Data Exchange (ETDEWEB)

    Li, M.; Zhou, Z.; Liao, L.; Chen, W.; Ge, C. [Univ. of Science and Technology Beijing, School of Materials Science and Engineering, Beijing (China)

    2010-07-01

    Oxide dispersion strengthened (ODS) iron based alloys are considered as promising high temperature structural material for advanced nuclear energy systems due to its higher creep strength and radiation damage resistance than conventional commercial steels. In this study, the oxidation behavior of ODS iron based alloys with different Cr content (12-18%) was investigated by exposing samples at high temperature of 700℃ and 1000℃ in atmosphere environment, the exposure time is up to 500 h. Results showed that 14Cr and 18Cr ODS alloys exhibited better oxidation resistance than 12Cr ODS alloys. For the same chromium content, the oxidation resistance of ODS alloys are better than that of non-ODS alloys. (author)

  10. Superelement methods applications to micromechanics of high temperature metal matrix composites

    Science.gov (United States)

    Caruso, J. J.; Chamis, C. C.

    1988-01-01

    Adaptation of the superelement finite-element method for micromechanics of continuous fiber high temperature metal matrix composites (HT-MMC) is described. The method is used to predict the thermomechanical behavior of P100-graphite/copper composites using MSC/NASTRAN and it is also used to validate those predicted by using an in-house computer program designed to perform micromechanics for HT-MMC. Typical results presented in the paper include unidirectional composite thermal properties, mechanical properties, and microstresses.

  11. High-temperature Superconductivity in Diamond Films - from Fundamentals to Device Applications

    Science.gov (United States)

    2014-12-20

    AND ADDRESS(ES) University of Melbourne Corner Swanston St. and Tin Alley Parkville, VIC Australia 8. PERFORMING ORGANIZATION REPORT...investigated the feasibility of ion implanting diamond plates with boron to create highly conducting, sub-surface layers. These layers hold great...implanted 2 MeV boron (B) ions into type-IIa diamond plates (followed by high temperature annealing to repair crystal damage) to create heavily doped

  12. High Temperature Pt/Alumina Co-Fired System for 500 C Electronic Packaging Applications

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

    2015-01-01

    Gold thick-film metallization and 96 alumina substrate based prototype packaging system developed for 500C SiC electronics and sensors is briefly reviewed, the needs of improvement are discussed. A high temperature co-fired alumina material system based packaging system composed of 32-pin chip-level package and printed circuit board is discussed for packaging 500C SiC electronics and sensors.

  13. Simulation of Thin Film Thermocouple for High Temperature Measurement Applicable to Missiles

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Sonker

    2015-09-01

    Full Text Available Thermocouples have been extensively used for the measurement of temperature since the advent of seebeck effect. Numerous sensors have been developed for temperature measurement, yet measurement of high temperature flowing fluid has been a challenging task. For the measurement of static temperature the measuring device should travel with the fluid at the same speed without disturbing the flow, which is quite unrealistic. So indirect determination of static temperature of flowing fluid is done by using thermocouple exposed into the flowing fluid. Other sensors available for high temperature measurement may lead to problems like resistance in the flow path of fluid which changes the structural dynamics. Thin film thermocouple (TFTC based on W-W26Re for super high temperature measurement has been investigated which can be used in missiles for surface temperature measurement of nozzle and rocket interior surface. TFTC does not cause disruption in the flow path with maintaining structural integrity. The W-W26Re thermocouple offers advantage of higher seebeck coefficient at high temperature i.e. above 750 K, and usability in vacuum, inert and hydrogen atmosphere. Zirconia Fiber has been proposed as insulation protection material over thermocouple. Modelling and simulation of the TFTC for the temperature range 300 K - 2900 K has been presented. FEA model using PDE has been presented to implement heat equation, current balance  quation, Gauss theorem and Neumann boundary condition. The expected voltage production on exposed temperature gradient has been studied.

  14. Analysis of dental hard tissues exposed to high temperatures for forensic applications: An in vitro study

    Directory of Open Access Journals (Sweden)

    Kuldeep Singh Shekhawat

    2016-01-01

    Full Text Available Aim: The aim of this study was to observe and record the macroscopic, radiographic, and microscopic findings obtained after subjecting the teeth to high temperatures. Materials and Methods: An in vitro study was conducted to observe macroscopic, radiographic, and microscopic changes in dental hard tissues in 60 unrestored non carious extracted human teeth. The teeth were grouped based on age: Below 30 years, 30–40 years, and above 40 years The teeth from each age group were further divided into five subgroups, and each subgroup was subjected to a particular temperature: 200$#176;C, 400$#176;C, 600°C, 800°C, and 1000°C. [C = Celsius]. Results: Various degrees of changes in relation to temperature were observed macroscopically, radiographically, and microscopically. The histological examination was limited for teeth exposed to 200°C. Conclusion: This investigation was carried out to study the gross changes, radiographic changes and histological changes in dental hard tissues exposed to high temperatures, which is an important part of forensic science. The aforementioned alterations caused by heat may provide useful information about temperature ranges and duration of exposure to high temperatures.

  15. Laboratory development and field application of novel cement system for cementing high-temperature oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Wan, X.; Zhang, H.; Li, Y.; Yang, Y. [SINOPEC, Beijing (China); Shan, H.; Xiao, Z. [OPT, Beijing (China)

    2010-07-01

    The challenges that oil and gas well engineers face when cementing mid-to-high temperature exploration oil and gas wells were discussed. A newly developed cement system with an effective laminar-flow spacer was presented along with case histories that document the system's effectiveness for cementing high temperature exploration wells. The problems associated with cementing high temperature exploration wells include high bottom hole static temperature; very low pump rates; and very long job times. These challenges contribute to the operational risks during cement slurry placement in the wellbore as well as during cement sheath setting during the life of the well. The new cement formulation presented in this paper addresses these challenges. Eight jobs have been completed in the field with much success. The combination of a new retarder and fluid loss control additive improves the system performance considerably in terms of low fluid loss rate, minimal free water, proper rheology, predictable thickening time, high resistance to salt contaminations and no adverse effect on set cement strength. The drilling muds are effectively displaced by the laminar flow spacer, thus improving the cementing bond. 9 refs., 5 tabs., 6 figs.

  16. Analysis of dental hard tissues exposed to high temperatures for forensic applications: An in vitro study

    Science.gov (United States)

    Shekhawat, Kuldeep Singh; Chauhan, Arunima

    2016-01-01

    Aim: The aim of this study was to observe and record the macroscopic, radiographic, and microscopic findings obtained after subjecting the teeth to high temperatures. Materials and Methods: An in vitro study was conducted to observe macroscopic, radiographic, and microscopic changes in dental hard tissues in 60 unrestored non carious extracted human teeth. The teeth were grouped based on age: Below 30 years, 30–40 years, and above 40 years The teeth from each age group were further divided into five subgroups, and each subgroup was subjected to a particular temperature: 200°C, 400°C, 600°C, 800°C, and 1000°C. [C = Celsius]. Results: Various degrees of changes in relation to temperature were observed macroscopically, radiographically, and microscopically. The histological examination was limited for teeth exposed to 200°C. Conclusion: This investigation was carried out to study the gross changes, radiographic changes and histological changes in dental hard tissues exposed to high temperatures, which is an important part of forensic science. The aforementioned alterations caused by heat may provide useful information about temperature ranges and duration of exposure to high temperatures. PMID:27555725

  17. Simulation of turbomachinery flows

    Science.gov (United States)

    Adamczyk, John J.

    1991-01-01

    With the interest in jet propulsion at the end of World War II, aerodynamicists were challenged to develop mathematical models which could be used to design turbomachinery components for jets. NASA Lewis engineers and scientists played a major role in meeting this challenge. Some of their accomplishments are highlighted as well as those of others. Several problems are addressed which must be solved if jet propulsion technology is to advance.

  18. Fabrication of Tungsten-Rhenium Cladding materials via Spark Plasma Sintering for Ultra High Temperature Reactor Applications

    Energy Technology Data Exchange (ETDEWEB)

    Charit, Indrajit; Butt, Darryl; Frary, Megan; Carroll, Mark

    2012-11-05

    This research will develop an optimized, cost-effective method for producing high-purity tungsten-rhenium alloyed fuel clad forms that are crucial for the development of a very high-temperature nuclear reactor. The study will provide critical insight into the fundamental behavior (processing-microstructure- property correlations) of W-Re alloys made using this new fabrication process comprising high-energy ball milling (HEBM) and spark plasma sintering (SPS). A broader goal is to re-establish the U.S. lead in the research field of refractory alloys, such as W-Re systems, with potential applications in very high-temperature nuclear reactors. An essential long-term goal for nuclear power is to develop the capability of operating nuclear reactors at temperatures in excess of 1,000K. This capability has applications in space exploration and some special terrestrial uses where high temperatures are needed in certain chemical or reforming processes. Refractory alloys have been identified as being capable of withstanding temperatures in excess of 1,000K and are considered critical for the development of ultra hightemperature reactors. Tungsten alloys are known to possess extraordinary properties, such as excellent high-temperature capability, including the ability to resist leakage of fissile materials when used as a fuel clad. However, there are difficulties with the development of refractory alloys: 1) lack of basic experimental data on thermodynamics and mechanical and physical properties, and 2) challenges associated with processing these alloys.

  19. Exogenous application of brassinolide can alter morphological and physiological traits of Leymus chinensis (Trin. Tzvelev under room and high temperatures

    Directory of Open Access Journals (Sweden)

    Jian-hang Niu

    2016-03-01

    Full Text Available Plant growth regulating substances are involved in the physiological and metabolic processes of plants and enable them to cope with numerous environmental stresses. The effect of exogenously applied brassinolide (BR with various concentrations (0.01, 0.1, and 1.0 mg L-1 was studied on morphological and physiological traits of Leymus chinensis (Trin. Tzvelev under room and high temperatures in pots. The experimental results revealed that high temperature stress substantially perturbed growth, photosynthetic pigments, and root activity of L. chinensis; however, the deleterious effects of high temperature were partially ameliorated by the foliar application of BR. Compared to room temperature, high temperature stress decreased the plant height, leaf area, plant fresh and dry weight, chlorophyll a and b content, chlorophyll a/b ratio as well as root activity, while exacerbated the membrane damage as indicated by enhanced production of malondialdehyde (MDA. Accumulation of proline content, soluble protein and sugar content in L. chinensis improved by heat stress, compared with normal temperature; application of BR further improved their production thus aiding in the attainment of tolerance against heat stress. Elevated levels of antioxidant enzymes such as superoxide dismutase (SOD, peroxidase (POD, catalase (CAT, ascorbate peroxidase (APX, and glutathione reductase (GR were observed under heat stress compared to room temperature, however, application of BR further proved beneficial in this regard. Our results indicated that BR could improve the growth and development of L. chinensis by enhancing the biosynthesis of photosynthetic pigments, osmolytes and antioxidant enzymes system in plants under both room and high temperature.

  20. High temperature materials and mechanisms

    CERN Document Server

    2014-01-01

    The use of high-temperature materials in current and future applications, including silicone materials for handling hot foods and metal alloys for developing high-speed aircraft and spacecraft systems, has generated a growing interest in high-temperature technologies. High Temperature Materials and Mechanisms explores a broad range of issues related to high-temperature materials and mechanisms that operate in harsh conditions. While some applications involve the use of materials at high temperatures, others require materials processed at high temperatures for use at room temperature. High-temperature materials must also be resistant to related causes of damage, such as oxidation and corrosion, which are accelerated with increased temperatures. This book examines high-temperature materials and mechanisms from many angles. It covers the topics of processes, materials characterization methods, and the nondestructive evaluation and health monitoring of high-temperature materials and structures. It describes the ...

  1. High Temperature Lightweight Self-Healing Ceramic Composites for Aircraft Engine Applications

    Science.gov (United States)

    Raj, Sai V.; Singh, Mrityunjay; Bhatt, Ramakrishna T.

    2014-01-01

    The present research effort was undertaken to develop a new generation of SiC fiber- reinforced engineered matrix composites (EMCs) with sufficient high temperature plasticity to reduce crack propagation and self-healing capabilities to fill surface-connected cracks to prevent the oxygen ingress to the fibers. A matrix engineered with these capabilities is expected to increase the load bearing capabilities of SiCSiC CMCs at high temperatures. Several matrix compositions were designed to match the coefficient of thermal expansion (CTE) of the SiC fibers using a rule of mixture (ROM) approach. The CTE values of these matrices were determined and it was demonstrated that they were generally in good agreement with that of monolithic SiC between room temperature and 1525 K. The parameters to hot press the powders were optimized, and specimens were fabricated for determining bend strength, CTE, oxidation and microstructural characteristics of the engineered matrices. The oxidation tests revealed that some of the matrices exhibited catastrophic oxidation, and therefore, these were eliminated from further consideration. Two promising compositions were down selected based on these results for further development. Four-point bend tests were conducted on these two promising matrices between room temperature and 1698 K. Although theses matrices were brittle and failed at low stresses at room temperature, they exhibited high temperature ductility and higher stresses at the higher temperatures. The effects of different additives on the self-healing capabilities of these matrices were investigated. The results of preliminary studies conducted to slurry and melt infiltration trials with CrSi2 are described.

  2. Simplified Design Criteria for Very High Temperature Applications in Generation IV Reactors

    Energy Technology Data Exchange (ETDEWEB)

    McGreevy, TE

    2004-12-15

    The goal of this activity is to provide simplified criteria which can be used in rapid feasibility assessments of the structural viability of very high temperature components in conceptual and early preliminary design phases for Generation IV reactors. The current criteria in ASME Code Section III, Subsection NH, hereafter referred to as NH, (and Code Case N-201 for core support structures) are difficult and require a complex deconstruction of finite element analysis results for their implementation. Further, and most important, times, temperatures and some materials of interest to the very high temperature Generation IV components are not covered by the current provisions of NH. Future revisions to NH are anticipated that will address very high temperature Generation IV components and materials requirements but, until that occurs interim guidance is required for design activities to proceed. These simplified criteria are for design guidance and are not necessarily in rigorous compliance with NH methodology. Rather, the objective is for criteria which address the early design needs of very high temperature Generation IV components and materials. The intent is to provide simplified but not overly conservative design methods. When more rigorous criteria and methods are incorporated in NH, the degree of conservatism should obviously be reduced. These criteria are based on currently available information. Although engineering judgments have been made in the formulation of these criteria they are not intended to require additional development or testing prior to implementation as a tool for use in conceptual and early preliminary design. Appendices are provided herein that contain useful information. The simplified methods were developed specifically with Alloy 617 in mind; however, they could be applied for the same intended purpose for other materials such as 9Cr-1Mo, Alloy 800H, etc. However, supporting design curves, stress allowables, and isochronous curves may

  3. Oxide fiber composites with promising properties for high-temperature structural applications

    Energy Technology Data Exchange (ETDEWEB)

    Simon, R.A. [Ceramic Materials Engineering, University of Bayreuth, 95440 Bayreuth (Germany); Danzer, R. [Institut fuer Struktur- und Funktionskeramik, Montanuniversitaet Leoben, 8700 Leoben (Austria)

    2006-11-15

    This paper summarizes the mechanical properties of recently developed Oxide Fiber Composites (OFCs) consisting of high-strength continuous oxide fibers embedded in an oxide matrix. The OFCs exhibit a favorable combination of high strength and damage tolerance due to unusual homogeneous microstructures. The tensile behavior in both fiber- and matrix-dominated loadings and interlaminar shear behavior are described. Special emphasis is placed on the attractive thermal shock resistance and high-temperature long-term performance of these new materials. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  4. Application of low-emissivity Pt layer on Ni alloy to high temperature

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Platinum films were sputter-deposited on two groups of nickel alloy substrates,in which the first group was the samples with rough surface,and the other group with polished surface.The platinum thin-films were applied to serve as the low-emissivity layers to reflect thermal radiation.Then,the platinum-coated samples were heated in air at 600℃ for 200 h to explore the effect of high-temperature environment on the emissivity of coated platinum film.After annealing,the average IR emissivity(at the wavelength o...

  5. High temperature UF6 RF plasma experiments applicable to uranium plasma core reactors

    Science.gov (United States)

    Roman, W. C.

    1979-01-01

    An investigation was conducted using a 1.2 MW RF induction heater facility to aid in developing the technology necessary for designing a self critical fissioning uranium plasma core reactor. Pure, high temperature uranium hexafluoride (UF6) was injected into an argon fluid mechanically confined, steady state, RF heated plasma while employing different exhaust systems and diagnostic techniques to simulate and investigate some potential characteristics of uranium plasma core nuclear reactors. The development of techniques and equipment for fluid mechanical confinement of RF heated uranium plasmas with a high density of uranium vapor within the plasma, while simultaneously minimizing deposition of uranium and uranium compounds on the test chamber peripheral wall, endwall surfaces, and primary exhaust ducts, is discussed. The material tests and handling techniques suitable for use with high temperature, high pressure, gaseous UF6 are described and the development of complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma, effluent exhaust gases, and residue deposited on the test chamber and exhaust system components is reported.

  6. Shear Melting and High Temperature Embrittlement: Theory and Application to Machining Titanium

    Science.gov (United States)

    Healy, Con; Koch, Sascha; Siemers, Carsten; Mukherji, Debashis; Ackland, Graeme J.

    2015-04-01

    We describe a dynamical phase transition occurring within a shear band at high temperature and under extremely high shear rates. With increasing temperature, dislocation deformation and grain boundary sliding are supplanted by amorphization in a highly localized nanoscale band, which allows for massive strain and fracture. The mechanism is similar to shear melting and leads to liquid metal embrittlement at high temperature. From simulation, we find that the necessary conditions are lack of dislocation slip systems, low thermal conduction, and temperature near the melting point. The first two are exhibited by bcc titanium alloys, and we show that the final one can be achieved experimentally by adding low-melting-point elements: specifically, we use insoluble rare earth metals (REMs). Under high shear, the REM becomes mixed with the titanium, lowering the melting point within the shear band and triggering the shear-melting transition. This in turn generates heat which remains localized in the shear band due to poor heat conduction. The material fractures along the shear band. We show how to utilize this transition in the creation of new titanium-based alloys with improved machinability.

  7. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Directory of Open Access Journals (Sweden)

    Weihua Xie

    2016-10-01

    Full Text Available This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs, which are equipped with chemical composition gratings sensors (CCGs. The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C.

  8. Shear melting and high temperature embrittlement: theory and application to machining titanium.

    Science.gov (United States)

    Healy, Con; Koch, Sascha; Siemers, Carsten; Mukherji, Debashis; Ackland, Graeme J

    2015-04-24

    We describe a dynamical phase transition occurring within a shear band at high temperature and under extremely high shear rates. With increasing temperature, dislocation deformation and grain boundary sliding are supplanted by amorphization in a highly localized nanoscale band, which allows for massive strain and fracture. The mechanism is similar to shear melting and leads to liquid metal embrittlement at high temperature. From simulation, we find that the necessary conditions are lack of dislocation slip systems, low thermal conduction, and temperature near the melting point. The first two are exhibited by bcc titanium alloys, and we show that the final one can be achieved experimentally by adding low-melting-point elements: specifically, we use insoluble rare earth metals (REMs). Under high shear, the REM becomes mixed with the titanium, lowering the melting point within the shear band and triggering the shear-melting transition. This in turn generates heat which remains localized in the shear band due to poor heat conduction. The material fractures along the shear band. We show how to utilize this transition in the creation of new titanium-based alloys with improved machinability.

  9. Results of the LIRES Round Robin test on high temperature reference electrodes for LWR applications

    Energy Technology Data Exchange (ETDEWEB)

    Bosch, R.W. [SCK.CEN, Nuclear Research Centre Belgium, Boeretang 200, B-2400 Mol (Belgium); Nagy, G. [Magyar Tudomanyos Akademia KFKI Atomenergia Kutatointezet, AEKI, Konkoly Thege ut 29-33, 1121 Budapest (Hungary); Feron, D. [CEA Saclay, 91191 Gif-Sur-Yvette Cedex (France); Navas, M. [CIEMAT, Edificio 30, Dpto. Fision Nuclear, Avda. Complutense 22, 28040 Madrid, (Spain); Bogaerts, W. [KU Leuven, Kasteelpark Arenberg 31, B-3001 Leuven (Belgium); Karnik, D. [Nuclear Research Institute, NRI, Rez (Czech Republic); Dorsch, T. [Framatone ANP, Inc., Charlotte, North Carolina (United States); Molander, A. [Studsvik AB SE-611 82 Nykoeping (Sweden); Maekelae, K. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland)

    2004-07-01

    A European sponsored research project has been started on 1 October 2000 to develop high temperature reference electrodes that can be used for in-core electrochemical measurements in Light Water Reactors (LWR's). This LIRES-project (Development of Light Water Reactor Reference Electrodes) consists of 9 partners (SCK-CEN, AEKI, CEA, CIEMAT, KU Leuven, NRI Rez, Framatone ANP, Studsvik Nuclear and VTT) and will last for four years. The main objective of this LIRES project is to develop a reference electrode, which is robust enough to be used inside a LWR. Emphasize is put on the radiation hardness of both the mechanical design of the electrode as the proper functioning of the electrode. A four steps development trajectory is foreseen: (1) To set a testing standard for a Round Robin, (2) To develop different reference electrodes, (3) To perform a Round Robin test of these reference electrodes followed by selection of the best reference electrode(s), (4) To perform irradiation tests under appropriate LWR conditions in a Material Test Reactor (MTR). Four different high temperature reference electrodes have been developed and are being tested in a Round Robin test. These electrodes are: A Ceramic Membrane Electrode (CME), a Rhodium electrode, an external Ag/AgCl electrode and a Palladium electrode. The presentation will focus on the results obtained with the Round Robin test. (authors)

  10. Application of CCG Sensors to a High-Temperature Structure Subjected to Thermo-Mechanical Load

    Science.gov (United States)

    Xie, Weihua; Meng, Songhe; Jin, Hua; Du, Chong; Wang, Libin; Peng, Tao; Scarpa, Fabrizio; Xu, Chenghai

    2016-01-01

    This paper presents a simple methodology to perform a high temperature coupled thermo-mechanical test using ultra-high temperature ceramic material specimens (UHTCs), which are equipped with chemical composition gratings sensors (CCGs). The methodology also considers the presence of coupled loading within the response provided by the CCG sensors. The theoretical strain of the UHTCs specimens calculated with this technique shows a maximum relative error of 2.15% between the analytical and experimental data. To further verify the validity of the results from the tests, a Finite Element (FE) model has been developed to simulate the temperature, stress and strain fields within the UHTC structure equipped with the CCG. The results show that the compressive stress exceeds the material strength at the bonding area, and this originates a failure by fracture of the supporting structure in the hot environment. The results related to the strain fields show that the relative error with the experimental data decrease with an increase of temperature. The relative error is less than 15% when the temperature is higher than 200 °C, and only 6.71% at 695 °C. PMID:27754356

  11. Enhancing thermal reliability of fiber-optic sensors for bio-inspired applications at ultra-high temperatures

    Science.gov (United States)

    Kang, Donghoon; Kim, Heon-Young; Kim, Dae-Hyun

    2014-07-01

    The rapid growth of bio-(inspired) sensors has led to an improvement in modern healthcare and human-robot systems in recent years. Higher levels of reliability and better flexibility, essential features of these sensors, are very much required in many application fields (e.g. applications at ultra-high temperatures). Fiber-optic sensors, and fiber Bragg grating (FBG) sensors in particular, are being widely studied as suitable sensors for improved structural health monitoring (SHM) due to their many merits. To enhance the thermal reliability of FBG sensors, thermal sensitivity, generally expressed as αf + ξf and considered a constant, should be investigated more precisely. For this purpose, the governing equation of FBG sensors is modified using differential derivatives between the wavelength shift and the temperature change in this study. Through a thermal test ranging from RT to 900 °C, the thermal sensitivity of FBG sensors is successfully examined and this guarantees thermal reliability of FBG sensors at ultra-high temperatures. In detail, αf + ξf has a non-linear dependence on temperature and varies from 6.0 × 10-6 °C-1 (20 °C) to 10.6 × 10-6 °C-1 (650 °C). Also, FBGs should be carefully used for applications at ultra-high temperatures due to signal disappearance near 900 °C.

  12. Developing scandium and zirconium containing aluminum boron carbide metal matrix composites for high temperature applications

    Science.gov (United States)

    Lai, Jing

    The study presented in this thesis focuses on developing castable, precipitation-strengthened Al--B4C metal matrix composites (MMCs) for high temperature applications. In the first part, B4C plates were immersed in liquid aluminum alloyed with Sc, Zr and Ti to investigate the interfacial reactions between B4C and liquid aluminum The influences of Sc, Zr and Ti on the interfacial microstructure in terms of individual and combined additions were examined. Results reveal that all three elements reacted with B4C and formed interfacial layers that acted as a diffusion barrier to limit the decomposition of B4C in liquid aluminum. The interfacial reactions and the reaction products in each system were identified. With the combined addition of Sc, Zr and Ti, most of the Ti was found to enrich at the interface, which not only offered appropriate protection of the B4C but also reduced the consumption of Sc and Zr at the interface. In the second part, Sc and Zr were introduced into Al-15vol.% B 4C composites presaturated by Ti, and eight experimental composites with different Sc and Zr levels were prepared via a conventional casting technique. It was found that Sc was involved in the interfacial reactions with B 4C that partially consume Sc. The Sc addition yielded considerable precipitation strengthening in the as-cast and peak aged conditions. To achieve an equivalent strengthening effect of Sc in binary Al-Sc alloys, approximately double the amount of Sc is required in Al-B4C composites. On the contrary, no major Zr reaction products were found at the interfaces and the major part of Zr remained in the matrix for the precipitation strengthening. The combination of Sc and Zr enhanced sthe precipitation strengthening. Two kinds of nanoscale precipitates, Al3Sc and Al3(Sc, Zr), were found in the as-cast microstructure and contributed to the increase in the matrix hardness. In the third part, all the experimental composites were isothermally aged at 300, 350, 400 and 450

  13. Improved oxidation resistance of ferritic steels with LSM coating for high temperature electrochemical applications

    DEFF Research Database (Denmark)

    Palcut, Marián; Mikkelsen, Lars; Neufeld, Kai

    2012-01-01

    The effect of single layer La0.85Sr0.15MnO3−δ (LSM) coatings on high temperature oxidation behaviour of four commercial chromia-forming steels, Crofer 22 APU, Crofer 22 H, E-Brite and AL 29-4C, is studied. The samples were oxidized for 140–1000 h at 1123 K in flowing simulated ambient air (air + 1......% H2O) and oxygen and corrosion kinetics monitored by mass increase of the materials over time. The oxide scale microstructure and chemical composition are investigated by scanning electron microscopy/energy-dispersive spectroscopy. The kinetic data obey a parabolic rate law. The results show...... that the LSM coating acts as an oxygen transport barrier that can significantly reduce the corrosion rate....

  14. Application of aluminum diffusion coatings to mitigate the KCl-induced high-temperature corrosion

    DEFF Research Database (Denmark)

    Kiamehr, Saeed; Lomholt, T. N.; Dahl, Kristian Vinter

    2017-01-01

    Pack cementation was used to produce Fe1−xAl and Fe2Al5 diffusion coatings on ferritic-martensitic steel P91 and a Ni2Al3 diffusion coating on pure nickel. The performance of diffusion coatings against high-temperature corrosion induced by potassium chloride (KCl) was evaluated by exposing......-ray diffractometry (XRD) before and after the exposures. It was found that all the diffusion coatings formed protective oxides under salt-free exposure in air. Under the salt deposit, Fe1−xAl showed local failure while on large parts of the sample a protective layer had formed. Fe2Al5 was attacked over the entire...

  15. The application of high temperature superconductors to space electrical power distribution components

    Science.gov (United States)

    Aron, Paul R.; Myers, Ira T.

    1988-01-01

    Some important space based electrical power distribution systems and components are examined to determine what might be achieved with the introduction of high temperature superconductors (HTS). Components that are compared in a before-and-after fashion include transformers, transmission lines, and capacitors. It is concluded that HTS has its greatest effect on the weight associated with transmission lines, where the weight penalty could be reduced by as much as 130 kg/kW/km of cable. Transformers, because 28 percent of their mass is in the conductor, are reduced in weight by the same factor. Capacitors are helped the least with only negligible savings possible. Finally, because HTS can relax the requirement to use alternating current in order to reduce conductor mass, it will be possible to generate significant savings by eliminating most transformers and capacitors.

  16. Application of high-temperature gas chromatography to the analysis of used frying fats

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, M.; Marmesat, S.; Ruiz Mendez, M. V.; Dobarganes, M. C.

    2010-07-01

    The determination of polar compounds is the most commonly applied technique in the analysis of used frying fats and oils. High-temperature gas chromatography allows for a quantitative determination of oxidized monomeric FAME and dimeric FAME thus giving extra information on oil degradation starting from the fraction of polar compounds. Polar compounds are trans esterified and methyl esters are separated in a VF-5ht Ultimetal column (150 degree centigrade -held for 5 min- rising at 5 degree centigrade min-1 to 370 degree centigrade and held for 5 min) using methyl tricosanoate as internal standard. Results are compared with those obtained by more complex alternative methodology using high-performance size-exclusion chromatography. (Author)

  17. High-speed, high-temperature magnetic bearings for jet turbine engine application

    Energy Technology Data Exchange (ETDEWEB)

    Mekhiche, M.; Nichols, S.; Hevenhill, D.; Oleksy, J.; Young, J.; Kirtley, J.L. [SatCon Technology Corporation, Cambridge, MA (United States)

    2000-08-01

    In order to double today's jet turbine engines' propulsion capability, lightweight, high-efficiency, high-speed and hightemperature components are sought. These requirements put the conventional components such as the mechanical bearings under excessive constraints and make them obsolete. In this context, SatCon Technology Corporation has developed a high-speed, high- temperature (50 krpm, 600 deg. C) magnetic bearing system that has the potential of meeting the requirements described above. This magnetic bearing system, comprised of two radial and one double acting thrust bearings, was successfully tested to 50,000 rpm. This paper describes the development of this system from its design, through its fabrication and final testing. Details on the system and component requirements are presented, along with a step-by step design and trade-off analysis. Test data and their discussion are provided as well. (orig.)

  18. High-temperature performance of a new nickel-based filler metal for power generation application

    Energy Technology Data Exchange (ETDEWEB)

    Shingledecker, J.; Coleman, K. [Electric Power Research Institute, Charlotte, NC (United States); Siefert, J.; Tanzosh, J. [Babcok and Wilcox Research Center, Barberton, OH (United States); Newell, W. [Euroweld, Mooresville, NC (United States)

    2010-07-01

    A new nickel-based weld filler metal, EPRI P87, has been developed as a superior alternative to ERNiCr-3 for use in dissimilar metal welds (DMW) between ferritic and austenitic materials. EPRI P87 has a low coefficient of thermal expansion more closely matching alloys such as Grade 91 and 92 than other available filler metals. Additionally, the size of the carbon denuded region adjacent to the weld in the heat-affected-zone is minimized/eliminated by proper control of weld metal composition. In this work the high-temperature mechanical behavior of DMWs utilizing EPRI P87 (GTAW and GMAW processes) was characterized through tensile and long-term creep-rupture testing. Microstructure analysis was also conducted on tested specimens to evaluate the HAZ regions and failure modes. Performance of the weld metal and welded joints is discussed and compared with ERNiCr-3 and typical 9%Cr-MoV filler metals. (orig.)

  19. High-temperature deformation and recrystallization: A variational analysis and its application to olivine aggregates

    Science.gov (United States)

    Hackl, Klaus; Renner, JöRg

    2013-03-01

    We develop a framework for a variational analysis of microstructural evolution during inelastic high-temperature deformation accommodated by dislocation mechanisms and diffusive mass transport. A polycrystalline aggregate is represented by a distribution function characterizing the state of individual grains by three variables, dislocation density, grain size, and elastic strain. The aggregate's free energy comprises elastic energy and energies of lattice distortions due to dislocations and grain boundaries. The work performed by the external loading is consumed by changes in the number of defects and their migration leading to inelastic deformation. The variational approach minimizes the rate of change of free energy with the evolution of the state variables under constraints on the aggregate volume, on a relation between changes in plastic strain and dislocation density, and on the form of the dissipation functionals for defect processes. The constrained minimization results in four basic evolution equations, one each for the evolution in grain size and dislocation density and flow laws for dislocation and diffusion creep. Analytical steady state scaling relations between stress and dislocation density and grain size (piezometers) are derived for quasi-homogeneous materials characterized by a unique relation between grain size and dislocation density. Our model matches all currently available experimental observations regarding high-temperature deformation of olivine aggregates with plausible values for the involved micromechanical model parameters. The relation between strain rate and stress for olivine aggregates maintaining a steady state microstructure is distinctly nonlinear in stark contrast to the majority of geodynamical modeling relying on linear relations, i.e., Newtonian behavior.

  20. Application of high temperature phase change materials for improved efficiency in waste-to-energy plants.

    Science.gov (United States)

    Dal Magro, Fabio; Xu, Haoxin; Nardin, Gioacchino; Romagnoli, Alessandro

    2017-06-28

    This study reports the thermal analysis of a novel thermal energy storage based on high temperature phase change material (PCM) used to improve efficiency in waste-to-energy plants. Current waste-to-energy plants efficiency is limited by the steam generation cycle which is carried out with boilers composed by water-walls (i.e. radiant evaporators), evaporators, economizers and superheaters. Although being well established, this technology is subjected to limitations related with high temperature corrosion and fluctuation in steam production due to the non-homogenous composition of solid waste; this leads to increased maintenance costs and limited plants availability and electrical efficiency. The proposed solution in this paper consists of replacing the typical refractory brick installed in the combustion chamber with a PCM-based refractory brick capable of storing a variable heat flux and to release it on demand as a steady heat flux. By means of this technology it is possible to mitigate steam production fluctuation, to increase temperature of superheated steam over current corrosion limits (450°C) without using coated superheaters and to increase the electrical efficiency beyond 34%. In the current paper a detailed thermo-mechanical analysis has been carried out in order to compare the performance of the PCM-based refractory brick against the traditional alumina refractory bricks. The PCM considered in this paper is aluminium (and its alloys) whereas its container consists of high density ceramics (such as Al2O3, AlN and Si3N4); the different coefficient of linear thermal expansion for the different materials requires a detailed thermo-mechanical analysis to be carried out to ascertain the feasibility of the proposed technology. Copyright © 2017. Published by Elsevier Ltd.

  1. Materials Properties Database for Selection of High-Temperature Alloys and Concepts of Alloy Design for SOFC Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z Gary; Paxton, Dean M.; Weil, K. Scott; Stevenson, Jeffry W.; Singh, Prabhakar

    2002-11-24

    To serve as an interconnect / gas separator in an SOFC stack, an alloy should demonstrate the ability to provide (i) bulk and surface stability against oxidation and corrosion during prolonged exposure to the fuel cell environment, (ii) thermal expansion compatibility with the other stack components, (iii) chemical compatibility with adjacent stack components, (iv) high electrical conductivity of the surface reaction products, (v) mechanical reliability and durability at cell exposure conditions, (vii) good manufacturability, processability and fabricability, and (viii) cost effectiveness. As the first step of this approach, a composition and property database was compiled for high temperature alloys in order to assist in determining which alloys offer the most promise for SOFC interconnect applications in terms of oxidation and corrosion resistance. The high temperature alloys of interest included Ni-, Fe-, Co-base superal

  2. High-Temperature Oxidation Behavior of Two Nickel-Based Superalloys Produced by Metal Injection Molding for Aero Engine Applications

    Science.gov (United States)

    Albert, Benedikt; Völkl, Rainer; Glatzel, Uwe

    2014-09-01

    For different high-temperature applications like aero engines or turbochargers, metal injection molding (MIM) of superalloys is an interesting processing alternative. For operation at high temperatures, oxidation behavior of superalloys produced by MIM needs to match the standard of cast or forged material. The oxidation behavior of nickel-based superalloys Inconel 713 and MAR-M247 in the temperature interval from 1073 K to 1373 K (800 °C to 1100 °C) is investigated and compared to cast material. Weight gain is measured discontinuously at different oxidation temperatures and times. Analysis of oxidized samples is done via SEM and EDX-measurements. MIM samples exhibit homogeneous oxide layers with a thickness up to 4 µm. After processing by MIM, Inconel 713 exhibits lower weight gain and thinner oxide layers than MAR-M247.

  3. Coal-Based Oxy-Fuel System Evaluation and Combustor Development; Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications

    Energy Technology Data Exchange (ETDEWEB)

    Hollis, Rebecca

    2013-03-31

    Clean Energy Systems, Inc. (CES) partnered with the U.S. Department of Energy’s National Energy Technology Laboratory in 2005 to study and develop a competing technology for use in future fossil-fueled power generation facilities that could operate with near zero emissions. CES’s background in oxy-fuel (O-F) rocket technology lead to the award of Cooperative Agreement DE-FC26-05NT42645, “Coal-Based Oxy-Fuel System Evaluation and Combustor Development,” where CES was to first evaluate the potential of these O-F power cycles, then develop the detailed design of a commercial-scale O-F combustor for use in these clean burning fossil-fueled plants. Throughout the studies, CES found that in order to operate at competitive cycle efficiencies a high-temperature intermediate pressure turbine was required. This led to an extension of the Agreement for, “Oxy-Fuel Turbomachinery Development for Energy Intensive Industrial Applications” where CES was to also develop an intermediate-pressure O-F turbine (OFT) that could be deployed in O-F industrial plants that capture and sequester >99% of produced CO2, at competitive cycle efficiencies using diverse fuels. The following report details CES’ activities from October 2005 through March 2013, to evaluate O-F power cycles, develop and validate detailed designs of O-F combustors (main and reheat), and to design, manufacture, and test a commercial-scale OFT, under the three-phase Cooperative Agreement.

  4. Synthesis and characterization of thermally stable palladium-based composite membranes for high temperature applications

    Science.gov (United States)

    Abu El Hawa, Hani W.

    In this thesis, the inert gas leak evolution problem in electroless-plated palladium-based composite membranes has been revisited. Palladium was doped with a higher melting point element such as ruthenium or platinum and the rate of increase of the nitrogen leak in the temperature range of 500-600 ºC was determined. The results showed that doping Pd with Pt or Ru significantly reduces the leak growth rate compared to a pure Pd membrane by almost one order of magnitude. The addition of Ru to Pd was sufficient to lower the leak growth rate, though the hydrogen permeance stability was not improved. The Pd-Pt alloy membrane, despite having a lower hydrogen permeance, had a stable hydrogen flux at higher temperatures. The influence of high temperature annealing (> 640 ºC) on the thermal stability of pure Pd composite membranes was also investigated in order to correlate between thermal stability and microstructural evolution. Pure Pd composite membranes were subjected to different high temperature annealing processes. It was found that employing such heat treatments improved the thermal stability of the membranes when operated at lower temperatures; evidenced by a suppression of the rate at which hydrogen selectivity towards nitrogen declined over time. SEM images of the microstructural evolution as a function of temperature revealed that porosity, which is typically present in as-deposited electroless plated films, is significantly reduced after heat treatment. Thermal stability was also evaluated in actual steam methane reforming (SMR) environments. Thin film (˜5.0 microm thick) Pd-Ru and Pd-Au composite membranes were fabricated and used to carry out SMR over commercial Ni or Ru based catalysts at temperatures > 480 °C and pressures up to 2.9 MPa. The conversions obtained (≥ 80%) were significantly higher than the thermodynamic equilibrium predicted (process conditions. The long term operation (> 500 hours) revealed the potential suitability of these Pd

  5. DMBZ Polyimides Provide an Alternative to PMR-15 for High-Temperature Applications

    Science.gov (United States)

    2005-01-01

    PMR-15, a high-temperature polyimide developed in the mid-1970's at the NASA Lewis Research Center, offers the combination of ease of processing, low cost, and good stability and performance at temperatures up to 288 C (500 F). This material is widely regarded as one of the leading high-temperature matrix resins for polymer-matrix-composite aircraft engine components. PMR-15 is widely used in both military and civilian aircraft engines. The current worldwide market for PMR-15 is on the order of 50,000 lb, with a total sales of around $5 to $10 million. However, PMR-15 is made from methylene dianiline (MDA), a known animal mutagen and a suspected human mutagen. Recent concerns about the safety of workers involved in the manufacture and repair of PMR-15 components have led to the implementation of costly protective measures to limit worker exposure and ensure workplace safety. In some cases, because of safety and economic concerns, airlines have eliminated PMR-15 components from engines in their fleets. Current efforts at Lewis are focused on developing suitable replacements for PMR-15 that do not contain mutagenic constituents and have processability, stability, and mechanical properties comparable to that of PMR-15. A recent development from these efforts is a new class of thermosetting polyimides based on 2,2'-dimethylbenzidine (DMBZ). Autoclave processing developed for PMR-15 composites was used to prepare low-void-content T650-35 carbon-fiber-reinforced laminates from DMBZ-15 polyimides. The glass transition temperatures of these laminates were about 50 C higher than those of the T650- 35/PMR-15 composites (400 versus 348 C). In addition, DMBZ-15 polyimide composites aged for 1000 hr in air at 288 C (500 F) had weight losses close to those of comparable PMR-15 laminates (0.9 versus 0.7 percent). The elevated (288 C) and room temperature mechanical properties of T650-35-reinforced DMBZ-15 polyimide and PMR-15 laminates were comparable. Standard Ames tests are

  6. Metamaterial-based high efficiency absorbers for high temperature solar applications (Conference Presentation)

    Science.gov (United States)

    Yellowhair, Julius E.; Kwon, Hoyeong; Alù, Andrea; Jarecki, Robert L.; Shinde, Subhash L.

    2016-09-01

    Operation of concentrated solar power receivers at higher temperatures (Existing coatings, however, tend to degrade rapidly at elevated temperatures. In this paper, we report on the initial designs, fabrication, and characterization of spectrally selective metamaterial-based absorbers for high-temperature, high-thermal flux environments important for solarized sCO2 power cycles. Metamaterials are structured media whose optical properties are determined by sub-wavelength structural features instead of bulk material properties, providing unique solutions by decoupling the optical absorption spectrum from thermal stability requirements. The key enabling innovative concept proposed is the use of structured surfaces with spectral responses that can be tailored to optimize the absorption and retention of solar energy for a given temperature range. In this initial study we use Tungsten for its stability in expected harsh environments, compatibility with microfabrication techniques, and required optical performance. Our goal is to tailor the optical properties for high (near unity) absorptivity across the majority of the solar spectrum and over a broad range of incidence angles, and at the same time achieve negligible absorptivity in the near infrared to optimize the energy absorbed and retained. To this goal, we apply the recently developed concept of plasmonic Brewster angle to suitably designed nanostructured Tungsten surfaces. We predict that this will improve the receiver thermal efficiencies by at least 10% over current solar receivers.

  7. Flexible Aerogel as a Superior Thermal Insulation for High Temperature Superconductor Cable Applications

    Science.gov (United States)

    White, S.; Demko, J.; Tomich, A.

    2010-04-01

    High temperature superconducting (HTS) cables are an advanced technology that can both strengthen and improve the national electrical distribution infrastructure. HTS cables require sufficient cooling to overcome inherent low temperature heat loading. Heat loads are minimized by the use of cryogenic envelopes or cryostats. Cryostats require improvement in efficiency, reliability, and cost reduction to meet the demanding needs of HTS conductors (1G and 2G wires). Aspen Aerogels has developed a compression resistant aerogel thermal insulation package to replace compression sensitive multi-layer insulation (MLI), the incumbent thermal insulation, in flexible cryostats for HTS cables. Oak Ridge National Laboratory tested a prototype aerogel package in a lab-scale pipe apparatus to measure the rate of heat invasion. The lab-scale pipe test results of the aerogel solution will be presented and directly compared to MLI. A compatibility assessment of the aerogel material with HTS system components will also be presented. The aerogel thermal insulation solution presented will meet the demanding needs of HTS cables.

  8. Application of a moving bed biofilm reactor for tertiary ammonia treatment in high temperature industrial wastewater.

    Science.gov (United States)

    Shore, Jennifer L; M'Coy, William S; Gunsch, Claudia K; Deshusses, Marc A

    2012-05-01

    This study examines the use of a moving bed biofilm reactor (MBBR) as a tertiary treatment step for ammonia removal in high temperature (35-45°C) effluents, and quantifies different phenotypes of ammonia and nitrite oxidizing bacteria responsible for nitrification at elevated temperatures. Bench scale reactors operating at 35 and 40°C were able to successfully remove greater than 90% of the influent ammonia (up to 19 mg L(-1) NH(3)-N) in both the synthetic and industrial wastewater. No biotreatment was observed at 45°C, although effective nitrification was rapidly recovered when the temperature was lowered to 30°C. Using qPCR, Nitrosomonas oligotropha was found to be the dominant ammonia oxidizing bacterium in the biofilm for the first phases of reactor operation. In the later phases, Nitrosomonas nitrosa was observed and its increased presence may have been responsible for improved ammonia treatment efficiency. Accumulation of nitrite in some instances appeared to correlate with temporary low presence of Nitrospira spp.

  9. High-sensitivity in situ QCLAS-based ammonia concentration sensor for high-temperature applications

    Science.gov (United States)

    Peng, W. Y.; Sur, R.; Strand, C. L.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

    2016-07-01

    A novel quantum cascade laser (QCL) absorption sensor is presented for high-sensitivity in situ measurements of ammonia (hbox {NH}_3) in high-temperature environments, using scanned wavelength modulation spectroscopy (WMS) with first-harmonic-normalized second-harmonic detection (scanned WMS-2 f/1 f) to neutralize the effect of non-absorption losses in the harsh environment. The sensor utilized the sQ(9,9) transition of the fundamental symmetric stretch band of hbox {NH}_3 at 10.39 {\\upmu }hbox {m} and was sinusoidally modulated at 10 kHz and scanned across the peak of the absorption feature at 50 Hz, leading to a detection bandwidth of 100 Hz. A novel technique was used to select an optimal WMS modulation depth parameter that reduced the sensor's sensitivity to spectral interference from hbox {H}_2hbox {O} and hbox {CO}_2 without significantly sacrificing signal-to-noise ratio. The sensor performance was validated by measuring known concentrations of hbox {NH}_3 in a flowing gas cell. The sensor was then demonstrated in a laboratory-scale methane-air burner seeded with hbox {NH}_3, achieving a demonstrated detection limit of 2.8 ± 0.26 ppm hbox {NH}_3 by mole at a path length of 179 cm, equivalence ratio of 0.6, pressure of 1 atm, and temperatures of up to 600 K.

  10. The US market for high-temperature superconducting wire in transmission cable applications

    Energy Technology Data Exchange (ETDEWEB)

    Forbes, D

    1996-04-01

    Telephone interviews were conducted with 23 utility engineers concerning the future prospects for high-temperature superconducting (HTS) transmission cables. All have direct responsibility for transmission in their utility, most of them in a management capacity. The engineers represented their utilities as members of the Electric Power Research Institute`s Underground Transmission Task Force (which has since been disbanded). In that capacity, they followed the superconducting transmission cable program and are aware of the cryogenic implications. Nineteen of the 23 engineers stated the market for underground transmission would grow during the next decade. Twelve of those specified an annual growth rate; the average of these responses was 5.6%. Adjusting that figure downward to incorporate the remaining responses, this study assumes an average growth rate of 3.4%. Factors driving the growth rate include the difficulty in securing rights-of-way for overhead lines, new construction techniques that reduce the costs of underground transmission, deregulation, and the possibility that public utility commissions will allow utilities to include overhead costs in their rate base. Utilities have few plans to replace existing cable as preventive maintenance, even though much of the existing cable has exceeded its 40-year lifetime. Ten of the respondents said the availability of a superconducting cable with the same life-cycle costs as a conventional cable and twice the ampacity would induce them to consider retrofits. The respondents said a cable with those characteristics would capture 73% of their cable retrofits.

  11. Corrosion Testing of Ni Alloy HVOF Coatings in High Temperature Environments for Biomass Applications

    Science.gov (United States)

    Paul, S.; Harvey, M. D. F.

    2013-03-01

    This paper reports the corrosion behavior of Ni alloy coatings deposited by high velocity oxyfuel spraying, and representative boiler substrate alloys in simulated high temperature biomass combustion conditions. Four commercially available oxidation resistant Ni alloy coating materials were selected: NiCrBSiFe, alloy 718, alloy 625, and alloy C-276. These were sprayed onto P91 substrates using a JP5000 spray system. The corrosion performance of the coatings varied when tested at ~525, 625, and 725 °C in K2SO4-KCl mixture and gaseous HCl-H2O-O2 containing environments. Alloy 625, NiCrBSiFe, and alloy 718 coatings performed better than alloy C-276 coating at 725 °C, which had very little corrosion resistance resulting in degradation similar to uncoated P91. Alloy 625 coatings provided good protection from corrosion at 725 °C, with the performance being comparable to wrought alloy 625, with significantly less attack of the substrate than uncoated P91. Alloy 625 performs best of these coating materials, with an overall ranking at 725 °C as follows: alloy 625 > NiCrBSiFe > alloy 718 ≫ alloy C-276. Although alloy C-276 coatings performed poorly in the corrosion test environment at 725 °C, at lower temperatures (i.e., below the eutectic temperature of the salt mixture) it outperformed the other coating types studied.

  12. MEMS fiber-optic Fabry-Perot pressure sensor for high temperature application

    Science.gov (United States)

    Fang, G. C.; Jia, P. G.; Cao, Q.; Xiong, J. J.

    2016-10-01

    We design and demonstrate a fiber-optic Fabry-Perot pressure sensor (FOFPPS) for high-temperature sensing by employing micro-electro-mechanical system (MEMS) technology. The FOFPPS is fabricated by anodically bonding the silicon wafer and the Pyrex glass together and fixing the facet of the optical fiber in parallel with the silicon surface by glass frit and organic adhesive. The silicon wafer can be reduced through dry etching technology to construct the sensitive diaphragm. The length of the cavity changes with the deformation of the diaphragm due to the loaded pressure, which leads to a wavelength shift of the interference spectrum. The pressure can be gauged by measuring the wavelength shift. The pressure experimental results show that the sensor has linear pressure sensitivities ranging from 0 kPa to 600 kPa at temperature range between 20°C to 300°C. The pressure sensitivity at 300°C is approximately 27.63 pm/kPa. The pressure sensitivities gradually decrease with increasing the temperature. The sensor also has a linear thermal drift when temperature changes from 20°C - 300°C.

  13. Facile preparation of graphene by high-temperature electrolysis and its application in supercapacitor.

    Science.gov (United States)

    Jiao, Chen-Xu; Xing, Bao-Yan; Zhao, Jian-Guo; Geng, Yu; Li, Zuo-Peng

    2014-01-01

    Graphene is well known owing to its astonishing properties: stronger than diamond, more conductive than copper and more flexible than rubber. Because of its potential uses in industry, researchers have been searching for less toxicity ways to make graphene in large amount with lower cost. We demonstrated an efficient method to prepare graphene by high temperature electrolysis technique. High resolution scanning electron microscopy and raman spectroscopy were used to characterize the microstructure of graphene. Graphene was assembled into the supercapacitor and its performance of electrochemical capacitor was investigated by constant current charge and discharge, cyclic voltammetry and AC impedance. The results showed that the micro-morphology of the prepared graphene was multilayer and it was favorable when the electrolytic voltage was 1.5 V. When the current density is 1 mA/cm(2), the specific capacitance of the graphene supercapacitor can reach 78.01 F/g in 6 mol/L KOH electrolyte, which was an increase of 114% compared with 36.43 F/g of conventional KOH electrolyte.

  14. Synthesis and Application of Novel Ruthenium Catalysts for High Temperature Alkene Metathesis

    Directory of Open Access Journals (Sweden)

    Tegene T. Tole

    2017-01-01

    Full Text Available Four pyridinyl alcohols and the corresponding hemilabile pyridinyl alcoholato ruthenium carbene complexes of the Grubbs second generation-type RuCl(H2IMes(O^N(=CHPh, where O^N = 1-(2′-pyridinyl-1,1-diphenyl methanolato, 1-(2′-pyridinyl-1-(2′-chlorophenyl,1-phenyl methanolato, 1-(2′-pyridinyl-1-(4′-chlorophenyl,1-phenyl methanolato and 1-(2′-pyridinyl-1-(2′-methoxyphenyl,1-phenyl methanolato, are synthesized in very good yields. At high temperatures, the precatalysts showed high stability, selectivity and activity in 1-octene metathesis compared to the Grubbs first and second generation precatalysts. The 2-/4-chloro- and 4-methoxy-substituted pyridinyl alcoholato ligand-containing ruthenium precatalysts showed high performance in the 1-octene metathesis reaction in the range 80–110 °C. The hemilabile 4-methoxy-substituted pyridinyl alcoholato ligand improved the catalyst stability, activity and selectivity for 1-octene metathesis significantly at 110 °C.

  15. Development of a design methodology for high-temperature cyclic application of materials which experience cyclic softening

    Energy Technology Data Exchange (ETDEWEB)

    Leckie, F.A.; Marriott, D.L.; Stubbins, J.F.; Handrock, J.L.; Kschinka, B.

    1987-08-01

    The project described in this report has, as its beginning, two investigations, the first a study of the effect of material softening on the overall structural stability of complex components, and the second an evaluation of damage induced through cyclic loads combined with high temperature environmental effects. The initial work was carried out on one grade of 2.25Cr 1Mo steel, with the intention of extending the investigation to other grades once the investigative techniques had been settled. However, considerable interest has grown in the application of modified forms of austenitic steel to very high temperature use in superheaters and reheaters. The ability to utilize these materials can mean an increase of 100{degree}C in the top temperature in a power plant, which converts into a significant improvement in thermal efficiency for a very small investment in material. Therefore, the direction of this project has been modified to continue on this class rather than the ferritic alloys originally under consideration. The basic problem to be investigated in the austenitics is the concern for possible strength variations, either positive or negative, induced in the very complex microstructures by service conditions of cyclic load and high temperature. 23 refs., 31 figs., 6 tabs.

  16. Joining of Zirconium Diboride-Based Ceramic Composites to Metallic Systems for High-Temperature Applications

    Science.gov (United States)

    Asthana, R.; Singh, M.

    2008-01-01

    Three types of hot-pressed zirconium diboride (ZrB2)-based ultra-high-temperature ceramic composites (UHTCC), ZrB2-SiC (ZS), ZrB2-SiC-C (ZSC), and ZrB2-SCS9-SiC (ZSS), were joined to Cu-clad-Mo using two Ag-Cu brazes (Cusil-ABA and Ticusil, T(sub L) approx.1073-1173 K) and two Pd-base brazes (Palco and Palni, T(sub L) approx.1493-1513 K). Scanning Electron Microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) revealed greater chemical interaction in joints made using Pd-base brazes than in joints made using Ag-Cu based active brazes. The degree of densification achieved in hot pressed composites influenced the Knoop hardness of the UHTCC and the hardness distribution across the braze interlayer. The braze region in Pd-base system displayed higher hardness in joints made using fully-dense ZS composites than in joints made using partially-dense ZSS composites and the carbon-containing ZSC composites. Calculations indicate a small negative elastic strain energy and an increase in the UHTCC's fracture stress up to a critical clad layer thickness . Above this critical thickness, strain energy in the UHTCC is positive, and it increases with increasing clad layer thickness. Empirical projections show a reduction in the effective thermal resistance of the joints and highlight the potential benefits of joining the UHTCC to Cu-clad-Mo.

  17. Production of Nanocrystalline Ni-20Cr Coatings for High-Temperature Applications

    Science.gov (United States)

    Kumar, Manoj; Singh, Harpreet; Singh, Narinder

    2014-04-01

    Presynthesized nanocrystalline Ni-20Cr powder was deposited on SA 516 and T91 boiler steels by a high-velocity oxy-fuel spraying process. Ni-20Cr powder was synthesized by the ball milling approach. The high-temperature oxidation behavior of bare and coated samples was then studied under cyclic isothermal conditions at 900 °C for 50 cycles. The kinetics of oxidation was established using weight change measurements for the bare and coated boiler steels. Uncoated and coated samples of T91 steel were exposed to the superheated zone of a power plant boiler at 750 °C under cyclic conditions for 15 cycles. Each cycle consisted of 100 h of heating followed by 1 h of cooling. Attempts were made to study the kinetics of erosion-corrosion using weight change and thickness loss data for the samples. Different characterization techniques were used to study the oxidized and eroded-corroded samples, including x-ray diffraction, scanning electron microscopy/energy-dispersive spectroscopy, and x-ray mapping analyses. The Ni-20Cr alloy powder coating was found to offer excellent oxidation resistance to the base steels and was successful in reducing the weight gain of SA 516 steel by 98.5 % and that of T91 steel by 65 %. The coating was observed to reduce the erosion-corrosion rate of T91 steel by 86 % in terms of thickness loss. This indicates that the investigated nanostructured coating can be a better choice over conventional coating for erosion-corrosion control of boiler tubes.

  18. A Study on Formation and Thermal Stability of Nano-sized Oxide Clusters in Mechanically Alloyed NiAl for High Temperature Applications

    OpenAIRE

    KIM, YONG-DEOG

    2012-01-01

    The intermetallic compound, B2 NiAl, is a promising material for high temperature structural applications such as in aviation jet engines or gas turbines, provided that its high temperature mechanical properties can be improved. Although extensive efforts over the last several decades have been devoted toward enhancing ductility through alloying design and reducing impurities, as well as improving high temperature creep strength through precipitation and dispersion strengthening, these effort...

  19. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

    The present book aims at describing the phenomenon of superconductivity and high-temperature superconductors discovered by Bednorz and Muller in 1986. The book covers the superconductivity phenomenon, structure of high-Tc superconductors, critical currents, synthesis routes for high Tc materials, superconductivity in cuprates, the proximity effect and SQUIDs, theories of superconductivity and applications of superconductors.

  20. Analysis of Possible Application of High-Temperature Nuclear Reactors to Contemporary Large-Output Steam Power Plants on Ships

    Directory of Open Access Journals (Sweden)

    Kowalczyk T.

    2016-04-01

    Full Text Available This paper is aimed at analysis of possible application of helium to cooling high-temperature nuclear reactor to be used for generating steam in contemporary ship steam-turbine power plants of a large output with taking into account in particular variable operational parameters. In the first part of the paper types of contemporary ship power plants are presented. Features of today applied PWR reactors and proposed HTR reactors are discussed. Next, issues of load variability of the ship nuclear power plants, features of the proposed thermal cycles and results of their thermodynamic calculations in variable operational conditions, are presented.

  1. Development of Austenitic ODS Strengthened Alloys for Very High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Stubbins, James [Univ. of Illinois, Urbana-Champaign, IL (United States); Heuser, Brent [Univ. of Illinois, Urbana-Champaign, IL (United States); Robertson, Ian [Kyushu Univ. (Japan); Sehitoglu, Huseyin [Univ. of Illinois, Urbana-Champaign, IL (United States); Sofronis, Petros [Kyushu Univ. (Japan); Gewirth, Andrew [Kyushu Univ. (Japan)

    2015-04-22

    This “Blue Sky” project was directed at exploring the opportunities that would be gained by developing Oxide Dispersion Strengthened (ODS) alloys based on the Fe-Cr-Ni austenitic alloy system. A great deal of research effort has been directed toward ferritic and ferritic/martensitic ODS alloys which has resulted in reasonable advances in alloy properties. Similar gains should be possible with austenitic alloy which would also take advantage of other superior properties of that alloy system. The research effort was aimed at the developing an in-depth understanding of the microstructural-level strengthening effects of ODS particles in austentic alloys. This was accomplished on a variety of alloy compositions with the main focus on 304SS and 316SS compositions. A further goal was to develop an understanding other the role of ODS particles on crack propagation and creep performance. Since these later two properties require bulk alloy material which was not available, this work was carried out on promising austentic alloy systems which could later be enhanced with ODS strengthening. The research relied on a large variety of micro-analytical techniques, many of which were available through various scientific user facilities. Access to these facilities throughout the course of this work was instrumental in gathering complimentary data from various analysis techniques to form a well-rounded picture of the processes which control austenitic ODS alloy performance. Micromechanical testing of the austenitic ODS alloys confirmed their highly superior mechanical properties at elevated temperature from the enhanced strengthening effects. The study analyzed the microstructural mechanisms that provide this enhanced high temperature performance. The findings confirm that the smallest size ODS particles provide the most potent strengthening component. Larger particles and other thermally- driven precipitate structures were less effective contributors and, in some cases, limited

  2. A new Cu-8 Cr-4 Nb alloy for high temperature applications

    Science.gov (United States)

    Ellis, D. L.; Michal, G. M.; Dreshfield, R. L.

    1995-01-01

    Various applications exist where a high conductivity alloy with good strength and creep resistance are required. NASA LeRC has developed a Cu-8 at. percent Cr-4 at. percent Nb (Cu-8 Cr-4 Nb) alloy for these applications. The alloy is designed for use up to 700 C and shows exceptional strength, low cycle fatigue (LCF) resistance, and creep resistance. Cu-8 Cr-4 Nb also has a thermal conductivity of at least 72 percent that of pure Cu. Furthermore, the microstructure and mechanical properties of the alloy are very stable. In addition to the original application in combustion chambers, Cu-8 Cr-4 Nb shows promise for welding electrodes, brazing fixtures, and other applications requiring high conductivity and strength at elevated temperatures.

  3. Very High Temperature Sound Absorption Coating Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I demonstrated experimentally a very high temperature acoustically absorbing coating for ducted acoustics applications. High temperature survivability at 3500...

  4. Effect of rhenium on short term oxidation of niobium based alloys for high temperature applications

    Science.gov (United States)

    Sierra, Ruth M.

    resulted in the negative weight gain. Alloys with this type of weight gain is advantageous as it refers to nullifying the formation of bulky Nb2O5. There was no metal left at 1400°C. Pesting was no observed at low temperature range. However, spalling was noticed at 1200 and 1300°C. Tungsten additions have helped in the formation of Nb5Si 3, Cr2Re3, NbCr2, and NbSS. All the phases formed were intermetallics, except the solid solution. These high temperature phases have helped to resist oxidation to an extent. The formation of a CrNbO 4 and SiO2 has helped in lowering the oxidation kinetics. No pesting was observed, spalling of the oxide was noticed only at 1300°C. Oxidation behavior of these alloys were characterized by the weight change per unit surface area method. Oxidation products were characterized by x-ray diffraction and scanning electron microscopy in several modes including backscatter imaging, secondary imaging, energy dispersive x-ray spectroscopy, and x-ray mapping

  5. Power Modulation Investigation for High Temperature (175-200 degrees Celcius) Automotive Application

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, F. P.

    2007-04-30

    advancing has been the development of electronics that can operate in the high temperature environments present in hybrid vehicles. The temperatures under the hood for a gasoline-electric hybrid vehicle are comparable to those for traditional internal combustion engines. This is known to be a difficult environment with respect to commercial-grade electronics, as there are surface and ambient temperatures ranging from 125 C to 175 C. In addition, some hybrid drive electronics are placed in even harsher environments, such as on or near the brakes, where temperatures can reach 250 C. Furthermore, number of temperature cycles experienced by electronics in a hybrid vehicle is different from that experienced in a traditional vehicle. A traditional internal combustion vehicle will have the engine running for longer periods, whereas a mild or micro-hybrid engine will experience many more starts and stops.[3] This means that hybrid automotive electronics will undergo more cycles of a potential wider temperature cycle than standard automotive electronics, which in turn see temperature cycles of 2 to 3 times the magnitude of the {Delta}T = 50 C-75 C experienced by commercial-grade electronics. This study will discuss the effects of these harsh environments on the failure mechanisms and ultimate reliability of electronic systems developed for gasoline-electric hybrid vehicles. In addition, it will suggest technologies and components that can reasonably be expected to perform well in these environments. Finally, it will suggest areas where further research is needed or desirable. Areas for further research will be highlighted in bold, italic type. It should be noted that the first area where further research is desirable is in developing a clearer understanding of the actual hybrid automotive electronics environment and how to simulate it through accelerated testing, thus: Developing specific mission profiles and accelerated testing protocols for the underhood environment for hybrid

  6. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

    Advances in High Temperature Chemistry, Volume 2 covers the advances in the knowledge of the high temperature behavior of materials and the complex and unfamiliar characteristics of matter at high temperature. The book discusses the dissociation energies and free energy functions of gaseous monoxides; the matrix-isolation technique applied to high temperature molecules; and the main features, the techniques for the production, detection, and diagnosis, and the applications of molecular beams in high temperatures. The text also describes the chemical research in streaming thermal plasmas, as w

  7. A Corrosion Investigation of Solder Candidates for High-Temperature Applications

    DEFF Research Database (Denmark)

    Chidambaram, Vivek; Hald, John; Ambat, Rajan;

    2009-01-01

    The step soldering approach is being employed in the Multi-Chip module (MCM) technology. High lead containing alloys is one of the solders currently being used in this approach. Au-Sn and Au-Ge based candidate alloys have been proposed as alternative solders for this application. In this work, co...

  8. Development of a FBG vortex flow sensor for high-temperature applications

    NARCIS (Netherlands)

    Cheng, L.K.; Schiferli, W.; Nieuwland, R.A.; Franzen, A.; Boer, J.J. den; Jansen, T.H.

    2011-01-01

    A robust fibre optic flow sensor has been developed to measure liquid or gas flows at ambient temperatures up to 300°C and pressures up to 100 bar. While such environmental conditions are typical in pressurized steam systems in the oil and gas industry (downhole and surface), wider applications are

  9. Development of high temperature silicone adhesive formulations for thermal protection system applications

    Science.gov (United States)

    Hockridge, R. R.

    1973-01-01

    Trade-off studies and screening evaluations were made of commercial polymers and silicone foam sheet stock. A low modulus, low density 0.26 gm/cc modification was developed of the GE-RESD PD-200 system based upon GE RTV-560 silicone polymer. The bond system modification was initially characterized for mechanical and thermal properties, evaluated for application methods, and its capability demonstrated as a strain arrestor bond system.

  10. Thermal Stability of GaAs Solar Cells for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yukun; Faucher, Joseph; Jung, Daehwan; Vaisman, Michelle; McPheeters, Clay; Sharps, Paul; Perl, Emmett; Simon, John; Steiner, Myles; Friedman, Daniel; Lee, Minjoo Larry

    2016-11-21

    The characteristics of GaAs solar cells after 200 hours of annealing at 400-450 degrees C are reported. The room-temperature reflectivity and external quantum efficiency (EQE) are unchanged after such heat treatments, and peak EQE values of 90% are observed both before and after. At an operating temperature of 400 degrees C, the performance of annealed cells was only slightly worse than cells that had not undergone any annealing; Voc = 0.55 V and FF = 66% were demonstrated for annealed cells tested at 400 degrees C under strong optical injection. These results constitute a promising first step towards photovoltaic applications that demand stable operation at elevated temperatures.

  11. High temperature performance of Wide Bandgap Semiconductors Devices for High Power Applications

    OpenAIRE

    2010-01-01

    Wide bandgap III-Nitride semiconductor materials possess superior properties as compared to silicon and other IIIV compound materials. GaN has recently attracted a lot of interest for applications in high power electronics capable of operation at elevated temperatures. Modeling of the drift region properties of GaN Schottky rectifiers and power MOSFET to achieve breakdown voltages ranging from 200 to 5kV is presented. 1kV and 3kV Schottky rectifiers are simulated and the characteristics of th...

  12. Present Status and Future Perspective of Bismuth-Based High-Temperature Superconducting Wires Realizing Application Systems

    Science.gov (United States)

    Sato, Ken-ichi; Kobayashi, Shin-ichi; Nakashima, Takayoshi

    2012-01-01

    Among a series of high-temperature superconducting materials that have been discovered to date, (Bi,Pb)2Sr2Ca2Cu3O10-x is the best candidate for superconducting wires that are long with commercial productivity, and critical current performance. In particular, the controlled overpressure (CT-OP) sintering technique gave us a 100% density of (Bi,Pb)2Sr2Ca2Cu3O10-x portion, which leads to robustness, increase in critical current, and mechanical tolerance. Many application prototypes are already verified and are being evaluated worldwide. Current leads for large magnets and magnetic billet heaters are already commercial products. Commercial applications for power cables, motors for ship propulsion and electric vehicles, and many kinds of magnets are promising in the near future.

  13. Duplex Al-based thermal spray coatings for corrosion protection in high temperature refinery applications

    Directory of Open Access Journals (Sweden)

    Rocha Adriana da Cunha

    2004-01-01

    Full Text Available The application of thermal spray coatings has been effective in preventing corrosion of steel and iron products. It has been used in a wide range of applications spreading from the petroleum to the food industry. In this work, the performance and effectiveness of a two-layered aluminum-based thermal spray coating applied to an ASTM A387 G11 steel was evaluated. The coating structure was comprised of an inner Al-Fe-Cr layer and an outer layer of aluminum. Coated samples were tested in the reactor zone of a fluid catalytic cracking unit (FCCU of a petrochemical plant for 2.5 years. The reactor zone temperature was about 793 K (520 °C and the environment was a mixed gas containing sulfur, oxygen and carbon. Laboratory-scale tests were also conducted on the coated samples in order to gain a better understanding of the corrosive effect of the gaseous species present in the FCCU atmosphere. Porosity present in the thermal spray coatings allowed the penetration of the atmosphere corrodents, which instigated intergranular corrosion of the steel substrate. The presence of an inner Al-Fe-Cr layer did not prevent coating spallation, which further contributed to the internal corrosion process.

  14. Advanced Multi-Junction Photovoltaic Device Optimization For High Temperature Space Applications

    Science.gov (United States)

    Sherif, Michael

    2011-10-01

    Almost all solar cells available today for space or terrestrial applications are optimized for low temperature or "room temperature" operations, where cell performances demonstrate favourable efficiency figures. The fact is in many space applications, as well as when using solar concentrators, operating cell temperature are typically highly elevated, where cells outputs are severely depreciated. In this paper, a novel approach for the optimization of multi-junction photovoltaic devices at such high expected operating temperature is presented. The device optimization is carried out on the novel cell physical model previously developed at the Naval Postgraduate School using the SILVACO software tools [1]. Taking into account the high cost of research and experimentation involved with the development of advanced cells, this successful modelling technique was introduced and detailed results were previously presented by the author [2]. The flexibility of the proposed methodology is demonstrated and example results are shown throughout the whole process. The research demonstrated the capability of developing a realistic model of any type of solar cell, as well as thermo-photovoltaic devices. Details of an example model of an InGaP/GaAs/Ge multi-junction cell was prepared and fully simulated. The major stages of the process are explained and the simulation results are compared to published experimental data. An example of cell parameters optimization for high operating temperature is also presented. Individual junction layer optimization was accomplished through the use of a genetic search algorithm implemented in Matlab.

  15. A High-Efficiency Refractive Secondary Solar Concentrator for High Temperature Solar Thermal Applications

    Science.gov (United States)

    Piszczor, Michael F., Jr.; Macosko, Robert P.

    2000-01-01

    A refractive secondary solar concentrator is a non-imaging optical device that accepts focused solar energy from a primary concentrator and redirects that light, by means of refraction and total internal reflection (TIR) into a cavity where the solar energy is used for power and/or propulsion applications. This concept offers a variety of advantages compared to typical reflective secondary concentrators (or the use of no secondary at all): higher optical efficiency, minimal secondary cooling requirements, a smaller cavity aperture, a reduction of outgassing from the cavity and flux tailoring of the solar energy within the heat receiver. During the past 2 years, NASA Lewis has been aggressively developing this concept in support of the NASA Marshall Shooting Star Flight Experiment. This paper provides a brief overview of the advantages and technical challenges associated with the development of a refractive secondary concentrator and the fabrication of a working unit in support of the flight demonstration program.

  16. High Strength and Wear Resistant Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.; Chen, Po Shou

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent thermal growth stability, surface hardness and wear resistant properties.

  17. Multilayer tungsten-alumina-based broadband light absorbers for high-temperature applications

    DEFF Research Database (Denmark)

    Chirumamilla, Manohar; Roberts, Alexander Sylvester; Ding, Fei;

    2016-01-01

    Efficient broadband absorption of visible and near-infrared light by low quality-factor metal-insulator-metal (MIM) resonators using refractory materials is reported. Omnidirectional absorption of incident light for broad angles of incidence and polarization insensitivity are observed for the fab......Efficient broadband absorption of visible and near-infrared light by low quality-factor metal-insulator-metal (MIM) resonators using refractory materials is reported. Omnidirectional absorption of incident light for broad angles of incidence and polarization insensitivity are observed...... the potential for a wide range of applications, including the use in commonly used infrared bands or absorbers for (solar) thermo-photovoltaic energy conversion, where high absorbance and simultaneously low (thermal) re-radiation is of paramount importance....

  18. Implementation Challenges for Sintered Silicon Carbide Fiber Bonded Ceramic Materials for High Temperature Applications

    Science.gov (United States)

    Singh, M.

    2011-01-01

    During the last decades, a number of fiber reinforced ceramic composites have been developed and tested for various aerospace and ground based applications. However, a number of challenges still remain slowing the wide scale implementation of these materials. In addition to continuous fiber reinforced composites, other innovative materials have been developed including the fibrous monoliths and sintered fiber bonded ceramics. The sintered silicon carbide fiber bonded ceramics have been fabricated by the hot pressing and sintering of silicon carbide fibers. However, in this system reliable property database as well as various issues related to thermomechanical performance, integration, and fabrication of large and complex shape components has yet to be addressed. In this presentation, thermomechanical properties of sintered silicon carbide fiber bonded ceramics (as fabricated and joined) will be presented. In addition, critical need for manufacturing and integration technologies in successful implementation of these materials will be discussed.

  19. Specifics of high-temperature sodium coolant purification technology in fast reactors for hydrogen production and other innovative applications

    Directory of Open Access Journals (Sweden)

    F.A. Kozlov

    2017-03-01

    Full Text Available In creating a large-scale atomic-hydrogen power industry, the resolution of technological issues associated with high temperatures in reactor plants (900°C and large hydrogen concentrations intended as long-term resources takes on particular importance. The paper considers technological aspects of removing impurities from high-temperature sodium used as a coolant in the high-temperature fast reactor (BN-HT 600MW (th. intended for the production of hydrogen as well as other innovative applications. The authors examine the behavior of impurities in the BN-HT circuits associated with the mass transfer intensification at high temperatures (Arrhenius law in different operating modes. Special attention is given to sodium purification from hydrogen, tritium and corrosion products in the BN-HT. Sodium purification from hydrogen and tritium by their evacuation through vanadium or niobium membranes will make it possible to develop compact highly-efficient sodium purification systems. It has been shown that sodium purification from tritium to concentrations providing the maximum permissible concentration of the produced hydrogen (3.6Bq/l according to NRB-99/2009 specifies more stringent requirements to the hydrogen removal system, i.e., the permeability index of the secondary tritium removal system should exceed 140kg/s. Provided that a BN-HN-type reactor meets these conditions, the bulk of tritium (98% will be accumulated in the compact sodium purification system of the secondary circuit, 0.6% (∼ 4·104Bq/s, will be released into the environment and 1.3% will enter the product (hydrogen. The intensity of corrosion products (CPs coming into sodium is determined by the corrosion rate of structural materials: at a high temperature level, a significant amount of corrosion products flows into sodium. The performed calculations showed that, for the primary BN-HT circuit, the amount of corrosion products formed at the oxygen concentration in sodium of 1mln

  20. ODS-materials for high temperature applications in advanced nuclear systems

    Directory of Open Access Journals (Sweden)

    C.C. Eiselt

    2016-12-01

    Full Text Available A ferritic ODS-alloy (Fe-14Cr-1W-0.25Ti has been manufactured by application of the powder metallurgical production route involving at first mechanical alloying of ∼10kg pre-alloyed steel powder together with an Y2O3 addition for 12h in a high energy industrial ball mill under hydrogen atmosphere at the company ZOZ GmbH. As a next step, one part of the alloyed powder was hot extruded into rods while another portion was hot isostatically pressed into plates. Both materials were then heat treated. A characterization program on these ODS-alloy production forms included microstructural and mechanical investigations: SANS and TEM assume the existence of Y2Ti2O7 nano clusters and show a bimodal distribution of ODS-particle sizes in both ODS variants. EBSD maps showed a strong 〈110〉 texture corresponding to the α fiber for the hot extruded ODS and a slight 〈001〉 texture for the hipped ODS material. Fracture toughness tests in different specimen orientations (extruded ODS with mini 0.2T C(T specimens together with Charpy impact tests revealed anisotropic mechanical properties: Promising (fracture toughness levels were obtained in the specimen orientation perpendicular to the extrusion direction, while the toughness levels remained low in extrusion direction and generally for the hipped ODS material at all test temperatures. The fracture toughness tests were performed according to ASTM E 1921 and 1820 standards.

  1. Max Phase Materials And Coatings For High Temperature Heat Transfer Applications

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Rodriguez, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Garcia-Diaz, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Olson, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fuentes, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Sindelar, R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-10-19

    Molten salts have been used as heat transfer fluids in a variety of applications within proposed Gen IV nuclear designs and in advanced power system such as Concentrating Solar Power (CSP). However, operating at elevated temperatures can cause corrosion in many materials. This work developed coating technologies for MAX phase materials on Haynes-230 and characterized the corrosion of the coatings in the presence of commercial MgCl2-KCl molten salt. Cold spraying of Ti2AlC and physical vapor deposition (PVD) of Ti2AlC or Zr2AlC were tested to determine the most effective form of coating MAX phases on structural substrates. Corrosion testing at 850°C for 100 hrs showed that 3.9 μm Ti2AlC by PVD was slightly protective while 117 μm Ti2AlC by cold spray and 3.6 μm Zr2AlC by PVD were completely protective. None of the tests showed decomposition of the coating (Ti or Zr) into the salt

  2. High-Temperature Phase Change Materials (PCM) Candidates for Thermal Energy Storage (TES) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J. C.

    2011-09-01

    It is clearly understood that lower overall costs are a key factor to make renewable energy technologies competitive with traditional energy sources. Energy storage technology is one path to increase the value and reduce the cost of all renewable energy supplies. Concentrating solar power (CSP) technologies have the ability to dispatch electrical output to match peak demand periods by employing thermal energy storage (TES). Energy storage technologies require efficient materials with high energy density. Latent heat TES systems using phase change material (PCM) are useful because of their ability to charge and discharge a large amount of heat from a small mass at constant temperature during a phase transformation like melting-solidification. PCM technology relies on the energy absorption/liberation of the latent heat during a physical transformation. The main objective of this report is to provide an assessment of molten salts and metallic alloys proposed as candidate PCMs for TES applications, particularly in solar parabolic trough electrical power plants at a temperature range from 300..deg..C to 500..deg.. C. The physical properties most relevant for PCMs service were reviewed from the candidate selection list. Some of the PCM candidates were characterized for: chemical stability with some container materials; phase change transformation temperatures; and latent heats.

  3. Development of powder metallurgy 2XXX series Al alloys for high temperature aircraft structural applications

    Science.gov (United States)

    Chellman, D. J.

    1984-01-01

    The objective of the present investigation was to improve the strength and fracture toughness combination of P/M 2124 Al alloys in accordance with NASA program goals for damage tolerance and fatigue resistance. Two (2) P/M compositions based on Al-3.70 Cu-1.85 Mg-0.20 Mn with 0.12 and 0.60 wt. pct. Zr were selected for investigation. The rapid solidification rates produced by atomization were observed to prohibit the precipitation of coarse, primary Al3Zr in both alloys. A major portion of the Zr precipitated as finely distributed, coherent Al3Zr phases during vacuum preheating and solution heat treatment. The proper balance between Cu and Mg contents eliminated undissolved, soluble constituents such as Al2CuMg and Al2Cu during atomization. The resultant extruded microstructures produced a unique combination of strength and fracture toughness. An increase in the volume fraction of coherent Al3Zr, unlike incoherent Al20Cu2Mn3 dispersoids, strengthened the P/M Al base alloy either directly by dislocation-precipitate interactions, indirectly by a retardation of recrystallization, or a combination of both mechanisms. Furthermore, coherent Al3Zr does not appear to degrade toughness to the extent that incoherent Al20Cu2Mn3 does. Consequently, the addition of 0.60 wt. pct. Zr to the base alloy, incorporated with a 774K (935 F) solution heat treatment temperature, produces an alloy which exceeds all tensile property and fracture toughness goals for damage tolerant and fatigue resistant applications in the naturally aged condition.

  4. Corrosion-resistant coatings for high-temperature high-sulfur- activity applications

    Energy Technology Data Exchange (ETDEWEB)

    Selman, J.R.; Aladjov, B.; Chen, B. (Illinois Inst. of Tech., Chicago, IL (United States). Chemical Engineering Dept.)

    1992-01-01

    The previously started experiments to verify the feasibility of obtaining molybdenum and molybdenum carbide coatings from oxide-based melts were continued. A molten salt bath consisting of an equimolar mixture of Na{sub 2}WO{sub 4} and K{sub 2}WO{sub 4} was used. The molybdenum and carbon species were introduced as alkali molybdate and carbonate. The coating morphology depends strongly on melt composition, temperature and moisture content. Application of initial pre-electrolysis significantly changes the composition and morphology of the coatings. Using non-lithium alkali salts, coatings of better quality were obtained. Adding 3-8 mol% Na{sub 2}B{sub 4}O{sub 7} to the basic non-lithium bath composition was observed to cause significant morphology and quality changes. Bath compositions produce a more uniform small-grain-size coating and they do not require extensive purification. Constant current and reverse and/or pulse current patterns were applied during plating. The latter produces smaller-grain-size coatings at the same working temperature. Research was undertaken to deposit Mo and Mo{sub 2} C films on a substrate 2.5 cm by 3.8 cm in area. Using an orthogonal factorial design, a new series of experiments has been carried out to investigate the effect of the evaporation rate of Mo(CO){sub 6} as a precursor. From the weight gain of the substrate, initial conclusions have been drawn about the optimal conditions for maximum evaporation rate, deposition rate and thickness. Thicker coatings (a few {mu}m) have been obtained which show two different types of crystallites growing on an initially amorphous film. A two dimensional transport and reaction kinetics model for a parallel-plate PECVD reactor was outlined. The PECVD results will be used to verify the model. The primary parameters to be explored are those representing the deposition kinetics of Mo and C.

  5. Corrosion-resistant coatings for high-temperature high-sulfur- activity applications. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Selman, J.R.; Aladjov, B.; Chen, B. [Illinois Inst. of Tech., Chicago, IL (United States). Chemical Engineering Dept.

    1992-01-01

    The previously started experiments to verify the feasibility of obtaining molybdenum and molybdenum carbide coatings from oxide-based melts were continued. A molten salt bath consisting of an equimolar mixture of Na{sub 2}WO{sub 4} and K{sub 2}WO{sub 4} was used. The molybdenum and carbon species were introduced as alkali molybdate and carbonate. The coating morphology depends strongly on melt composition, temperature and moisture content. Application of initial pre-electrolysis significantly changes the composition and morphology of the coatings. Using non-lithium alkali salts, coatings of better quality were obtained. Adding 3-8 mol% Na{sub 2}B{sub 4}O{sub 7} to the basic non-lithium bath composition was observed to cause significant morphology and quality changes. Bath compositions produce a more uniform small-grain-size coating and they do not require extensive purification. Constant current and reverse and/or pulse current patterns were applied during plating. The latter produces smaller-grain-size coatings at the same working temperature. Research was undertaken to deposit Mo and Mo{sub 2} C films on a substrate 2.5 cm by 3.8 cm in area. Using an orthogonal factorial design, a new series of experiments has been carried out to investigate the effect of the evaporation rate of Mo(CO){sub 6} as a precursor. From the weight gain of the substrate, initial conclusions have been drawn about the optimal conditions for maximum evaporation rate, deposition rate and thickness. Thicker coatings (a few {mu}m) have been obtained which show two different types of crystallites growing on an initially amorphous film. A two dimensional transport and reaction kinetics model for a parallel-plate PECVD reactor was outlined. The PECVD results will be used to verify the model. The primary parameters to be explored are those representing the deposition kinetics of Mo and C.

  6. Ultra-high temperature steam corrosion of complex silicates for nuclear applications: A computational study

    Science.gov (United States)

    Rashkeev, Sergey N.; Glazoff, Michael V.; Tokuhiro, Akira

    2014-01-01

    Stability of materials under extreme conditions is an important issue for safety of nuclear reactors. Presently, silicon carbide (SiC) is being studied as a cladding material candidate for fuel rods in boiling-water and pressurized water-cooled reactors (BWRs and PWRs) that would substitute or modify traditional zircaloy materials. The rate of corrosion of the SiC ceramics in hot vapor environment (up to 2200 °C) simulating emergency conditions of light water reactor (LWR) depends on many environmental factors such as pressure, temperature, viscosity, and surface quality. Using the paralinear oxidation theory developed for ceramics in the combustion reactor environment, we estimated the corrosion rate of SiC ceramics under the conditions representing a significant power excursion in a LWR. It was established that a significant time - at least 100 h - is required for a typical SiC braiding to significantly degrade even in the most aggressive vapor environment (with temperatures up to 2200 °C) which is possible in a LWR at emergency condition. This provides evidence in favor of using the SiC coatings/braidings for additional protection of nuclear reactor rods against off-normal material degradation during power excursions or LOCA incidents. Additionally, we discuss possibilities of using other silica based ceramics in order to find materials with even higher corrosion resistance than SiC. In particular, we found that zircon (ZrSiO4) is also a very promising material for nuclear applications. Thermodynamic and first-principles atomic-scale calculations provide evidence of zircon thermodynamic stability in aggressive environments at least up to 1535 °C.

  7. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Elshabini, Aicha [University of Idaho; Barlow, Fred D. [University of Idaho

    2006-11-01

    A key issue associated with the wider adoption of hybrid-electric vehicles (HEV) and plug in hybrid-electric vehicles (PHEV) is the implementation of the power electronic systems that are required in these products. One of the primary industry goals is the reduction in the price of these vehicles relative to the cost of traditional gasoline powered vehicles. Today these systems, such as the Prius, utilize one coolant loop for the engine at approximately 100 C coolant temperatures, and a second coolant loop for the inverter at 65 C. One way in which significant cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE). This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. Traditional power modules and the state-of-the-art inverters in the current HEV products, are based on chip and wire assembly and direct bond copper (DBC) on ceramic substrates. While a shift to silicon carbide (SiC) devices from silicon (Si) devices would allow the higher operating temperatures required for a single coolant loop, it also creates a number of challenges for the assembly of these devices into power inverters. While this traditional packaging technology can be extended to higher temperatures, the key issues are the substrate material and conductor stability, die bonding material, wire bonds, and bond metallurgy reliability as well as encapsulation materials that are stable at high operating temperatures. The larger temperature differential during power cycling, which would be created by higher coolant temperatures, places tremendous stress on traditional aluminum wire bonds that are used to interconnect power devices. Selection of the bond metallurgy and wire bond

  8. Durability of polyimide adhesives and their bonded joints for high-temperature applications

    Science.gov (United States)

    Parvatareddy, Hari

    The objective of this study was to evaluate and develop an understanding of durability of an adhesive bonded system, for application in a future high speed civil transport (HSCT) aircraft structure. The system under study was comprised of Ti-6Al-4V metal adherends and a thermosetting polyimide adhesive, designated as FM-5, supplied by Cytec Engineered Materials, Inc. An approach based on fracture mechanics was employed to assess Ti-6Al-4V/FM-5 bond durability. Initially, wedge tests were utilized to find a durable surface pretreatment for the titanium adherends. Based on an extensive screening study, chromic acid anodization (CAA) was chosen as the standard pretreatment for this research project. Double cantilever beam specimens (DCB) were then made and aged at 150sp°C, 177sp°C, and 204sp°C in three different environments; ambient atmospheric air (14.7 psia), and reduced air pressures of 2 psia (13.8 KPa) and 0.2 psia (1.38 KPa). Joints were aged for up to 18 months (including several intermediate aging times) in the above environments. The strain energy release rate (G) of the adhesive joints was monitored as a function of exposure time in the different environments. A 40% drop in fracture toughness was noted over the 18 month period, with the greatest degradation observed in samples aged at 204sp°C in ambient atmospheric air pressure. The loss in adhesive bond performance with time was attributable to a combination of physical and chemical aging phenomena in the FM-5 resin, and possible degradation of the metal-adhesive interface(s). Several mechanical and material tests, performed on the bonded joints and neat FM-5 resin specimens, confirmed the above statement. It was also noted that physical aging could be "erased" by thermal rejuvenation, partially restoring the toughness of the FM-5 adhesive material. The FM-5 adhesive material displayed good chemical resistance towards organic solvents and other aircraft fluids such as jet fuel and hydraulic fluid. The

  9. High-Temperature High-Power Packaging Techniques for HEV Traction Applications

    Energy Technology Data Exchange (ETDEWEB)

    Elshabini, Aicha [University of Idaho; Barlow, Fred D. [University of Idaho

    2006-11-01

    A key issue associated with the wider adoption of hybrid-electric vehicles (HEV) and plug in hybrid-electric vehicles (PHEV) is the implementation of the power electronic systems that are required in these products. One of the primary industry goals is the reduction in the price of these vehicles relative to the cost of traditional gasoline powered vehicles. Today these systems, such as the Prius, utilize one coolant loop for the engine at approximately 100 C coolant temperatures, and a second coolant loop for the inverter at 65 C. One way in which significant cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE). This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. Traditional power modules and the state-of-the-art inverters in the current HEV products, are based on chip and wire assembly and direct bond copper (DBC) on ceramic substrates. While a shift to silicon carbide (SiC) devices from silicon (Si) devices would allow the higher operating temperatures required for a single coolant loop, it also creates a number of challenges for the assembly of these devices into power inverters. While this traditional packaging technology can be extended to higher temperatures, the key issues are the substrate material and conductor stability, die bonding material, wire bonds, and bond metallurgy reliability as well as encapsulation materials that are stable at high operating temperatures. The larger temperature differential during power cycling, which would be created by higher coolant temperatures, places tremendous stress on traditional aluminum wire bonds that are used to interconnect power devices. Selection of the bond metallurgy and wire bond

  10. Closed Brayton Cycle power system with a high temperature pellet bed reactor heat source for NEP applications

    Science.gov (United States)

    Juhasz, Albert J.; El-Genk, Mohamed S.; Harper, William B., Jr.

    1992-01-01

    Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems.

  11. A Natural Application for High Temperature Superconductors: a Bearing for the Azimuth Mount of a Lunar Telescope

    Science.gov (United States)

    Ma, Ki; Lamb, Mark; Chen, Peter; Wilson, Thomas; Cooley, Rodger; Xia, Harold; Fowler, Clay; Chen, Quark; Chu, Wei-Kan

    1995-01-01

    A bearing for telescope mounts on the moon has to function in a cold dusty vacuum environment that impairs the operation of almost all traditional bearings, but it is a natural environment for bearings constructed out of magnets and high temperature superconductors. The challenge lies not so much in the weight of the telescope that has to be supported, but in the smoothness of forces required for precision positioning control over a long stretch of time without human intervention. In this paper, we present a design of hybrid superconductor magnet bearings intended for use on the azimuth mount of an altitude-azimuth telescope mount system. In addition to the general features of hybrid super conducting magnet bearings, we will address particular issues connected with the application of these bearings on a telescope mount.

  12. Tailored benzoxazines as novel resin systems for printed circuit boards in high temperature e-mobility applications

    Energy Technology Data Exchange (ETDEWEB)

    Troeger, K., E-mail: altstaedt@uni-bayreuth.de; Darka, R. Khanpour, E-mail: altstaedt@uni-bayreuth.de; Neumeyer, T., E-mail: altstaedt@uni-bayreuth.de; Altstaedt, V., E-mail: altstaedt@uni-bayreuth.de [Polymer Engineering, University of Bayreuth, Germany and Polymer Engineering, Universitaetsstrasse 30, 95447 Bayreuth (Germany)

    2014-05-15

    This study focuses on the development of Bisphenol-F-benzoxazine resins blended with different ratios of a trifunctional epoxy resin suitable as matrix for substrates for high temperature printed circuit board (HT-PCB) applications. With the benzoxazine blends glass transition temperatures of more than 190 °C could be achieved in combination with a coefficient of thermal expansion in thickness direction (z-CTE) of less than 60 ppm/K without adding any fillers. This shows the high potential of the benzoxazine-epoxy blend systems as substrate materials for HT-PCBs. To understand the thermal behavior of the different formulations, the apparent crosslink density was calculated based on data from Dynamic Mechanical Analysis. Laminates in laboratory scale were prepared and characterized to demonstrate the transformation of the neat resin properties into real electronic substrate properties. The produced laminates exhibit a z-CTE below 40 ppm/K.

  13. Tailored benzoxazines as novel resin systems for printed circuit boards in high temperature e-mobility applications

    Science.gov (United States)

    Troeger, K.; Darka, R. Khanpour; Neumeyer, T.; Altstaedt, V.

    2014-05-01

    This study focuses on the development of Bisphenol-F-benzoxazine resins blended with different ratios of a trifunctional epoxy resin suitable as matrix for substrates for high temperature printed circuit board (HT-PCB) applications. With the benzoxazine blends glass transition temperatures of more than 190 °C could be achieved in combination with a coefficient of thermal expansion in thickness direction (z-CTE) of less than 60 ppm/K without adding any fillers. This shows the high potential of the benzoxazine-epoxy blend systems as substrate materials for HT-PCBs. To understand the thermal behavior of the different formulations, the apparent crosslink density was calculated based on data from Dynamic Mechanical Analysis. Laminates in laboratory scale were prepared and characterized to demonstrate the transformation of the neat resin properties into real electronic substrate properties. The produced laminates exhibit a z-CTE below 40 ppm/K.

  14. Development of Polybenzimidazole-Based High-Temperature Membrane and Electrode Assemblies for Stationary and Automotive Applications

    Energy Technology Data Exchange (ETDEWEB)

    Vogel, John A.

    2008-09-03

    The program began on August 1, 2003 and ended on July 31, 2007. The goal of the project was to optimize a high-temperature polybenzimidazole (PBI) membrane to meet the performance, durability, and cost targets required for stationary fuel cell applications. These targets were identified in the Fuel Cell section (3.4) of DOE’s Hydrogen, Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan. A membrane that operates at high temperatures is important to the fuel cell industry because it is insensitive to carbon monoxide (a poison to low-temperature fuel cells), and does not require complex water management strategies. Together, these two benefits greatly simplify the fuel cell system. As a result, the high-temperature fuel cell system realizes a cost benefit as the number of components is reduced by nearly 30%. There is also an inherent reliability benefit as components such as humidifiers and pumps for water management are unnecessary. Furthermore, combined heat and power (CHP) systems may be the best solution for a commercial, grid-connected, stationary product that must offer a cost benefit to the end user. For a low-temperature system, the quality of the heat supplied is insufficient to meet consumer needs and comfort requirements, so peak heaters or supplemental boilers are required. The higher operating temperature of PBI technology allows the fuel cell to meet the heat and comfort demand without the additional equipment. Plug Power, working with the Rensselaer Polytechnic Institute (RPI) Polymer Science Laboratory, made significant advances in optimizing the PBI membrane material for operation at temperatures greater than 160oC with a lifetime of 40,000 hours. Supporting hardware such as flow field plates and a novel sealing concept were explored to yield the lower-cost stack assembly and corresponding manufacturing process. Additional work was conducted on acid loss, flow field design and cathode electrode

  15. Unsteady aerodynamic interaction effects on turbomachinery blade life and performance

    Science.gov (United States)

    Adamczyk, John J.

    1992-01-01

    This paper is an attempt to address the impact of a class of unsteady flows on the life and performance of turbomachinery blading. These class of flows to be investigated are those whose characteristic frequency is an integral multiple of rotor shaft speed. Analysis of data recorded downstream of a compressor and turbine rotor will reveal that this class of flows can be highly three-dimensional and may lead to the generation of secondary flows within downstream blading. By explicitly accounting for these unsteady flows in the design of turbomachinery blading for multistage applications, it may be possible to bring about gains in performance and blade life.

  16. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  17. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  18. High Temperature Materials Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The High Temperature Materials Lab provides the Navy and industry with affordable high temperature materials for advanced propulsion systems. Asset List: Arc Melter...

  19. Material Science for High-Efficiency Photovoltaics: From Advanced Optical Coatings to Cell Design for High-Temperature Applications

    Science.gov (United States)

    Perl, Emmett Edward

    a top junction. These designs maximize reflection of high-energy light for an InGaN top junction while minimizing reflection of low-energy light that would be absorbed by the lower four junctions. Increasing the reflectivity of high-energy photons enables a second pass of light through the InGaN cell, leading to increased absorption and a higher photocurrent. These optical designs enhanced the efficiency of a 2.65eV InGaN solar cell to a value of 3.3% under the AM0 spectrum, the highest reported efficiency for a standalone InGaN solar cell. The second half of the dissertation describes the development of III-V solar cells for high-temperature applications. As the operating temperature of a solar cell is increased, the ideal bandgap of the top junction increases. AlGaInP solar cells with bandgaps ranging from 1.9eV to 2.2eV are developed. A 2.03eV AlGaInP solar cell is demonstrated with a bandgap-voltage offset of 440mV, the lowest of any AlGaInP solar cell reported to date. Single-junction AlGaInP, GaInP, and GaAs solar cells designed for high-temperature operation are characterized up to a temperature of 400°C. The cell properties are compared to an analytical drift-diffusion model, and we find that a fundamental increase in the intrinsic carrier concentration, ni, dominates the temperature dependence of the dark currents, open-circuit voltage, and cell efficiency. These findings provide a valuable guide to the design of any system that requires high-temperature solar cell operation.

  20. Electrical properties of n-type multicrystalline silicon for photovoltaic application-Impact of high temperature boron diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Jourdan, J.; Dubois, S.; Cabal, R. [INES - CEA Grenoble, 50 avenue du Lac Leman, bat. PUMA2, 73370, Le Bourget du Lac (France); Veschetti, Y. [INES - CEA Grenoble, 50 avenue du Lac Leman, bat. PUMA2, 73370, Le Bourget du Lac (France)], E-mail: Yannick.Veschetti@cea.fr

    2009-03-15

    The effects of boron diffusion were investigated on electronic grade n-type single- and multicrystalline silicon wafers for solar cells application. Doped p{sup +}-layers were formed using specific spin-on dopant (SOD) source annealed in a tube furnace. Homogeneous diffused layers with sheet resistance values of 70 {omega}/sq were achieved on large area silicon wafers. Bulk electrical properties were investigated measuring the effective carrier lifetime after the diffusion step. A significant degradation of the bulk electrical properties was observed using the SOD technique. Unlike for the single-crystalline silicon, it was determined that this effect was not due to an interstitial iron contamination originating from the SOD, but rather by the thermal degradation of the material. Boron diffusion was followed by a phosphorous diffusion sequence, necessary in the fabrication process for the formation of the back surface field. This additional step leads to an improvement of effective lifetime values due to an efficient gettering of the impurities. Finally, bulk carrier lifetimes from 100 {mu}s to over 300 {mu}s were deduced on n-type multicrystalline silicon after boron and phosphorus diffusion. This underlines the potential of this material for photovoltaic application and its stability after high temperature treatments provided that a gettering step is included after the boron diffusion step.

  1. Surface Effects and Challenges for Application of Piezoelectric Langasite Substrates in Surface Acoustic Wave Devices Caused by High Temperature Annealing under High Vacuum

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2015-12-01

    Full Text Available Substrate materials that are high-temperature stable are essential for sensor devices which are applied at high temperatures. Although langasite is suggested as such a material, severe O and Ga diffusion into an O-affine deposited film was observed during annealing at high temperatures under vacuum conditions, leading to a damage of the metallization as well as a change of the properties of the substrate and finally to a failure of the device. Therefore, annealing of bare LGS (La 3 Ga 5 SiO 14 substrates at 800 ∘ C under high vacuum conditions is performed to analyze whether this pretreatment improves the suitability and stability of this material for high temperature applications in vacuum. To reveal the influence of the pretreatment on the subsequently deposited metallization, RuAl thin films are used as they are known to oxidize on LGS at high temperatures. A local study of the pretreated and metallized substrates using transmission electron microscopy reveals strong modification of the substrate surface. Micro cracks are visible. The composition of the substrate is strongly altered at those regions. Severe challenges for the application of LGS substrates under high-temperature vacuum conditions arise from these substrate damages, revealing that the pretreatment does not improve the applicability.

  2. High-Temperature Erosion Resistance of FeBSiNb Amorphous Coatings Deposited by Arc Spraying for Boiler Applications

    Science.gov (United States)

    Cheng, J. B.; Liang, X. B.; Chen, Y. X.; Wang, Z. H.; Xu, B. S.

    2013-06-01

    Erosive high-temperature wear in boilers is one of the main causes of downtime and one of the principal engineering problems in these installations. This article discusses the use of FeBSiNb amorphous coatings synthesized by arc spraying to improve elevated-temperature erosion resistance for boiler applications. The influence of test temperature, velocity, and impact angle on material wastage was revealed using air solid particle erosion rig. The experimental results showed that moderate degradation of the coating was predominant at lower impact velocity and impact angles, while severe damage arose for higher velocities and impact angles. The erosion behavior of the coating was sensitive to test temperature. The erosion rates of the coating decreased as a function of environment temperature. The relationship between microstructure and erosion resistance of the coating was also analyzed in details. The FeBSiNb coating had excellent elevated-temperature erosion resistance at temperatures at least up to 600 °C during service.

  3. Facile synthesis of iron oxides/reduced graphene oxide composites: application for electromagnetic wave absorption at high temperature

    Science.gov (United States)

    Zhang, Lili; Yu, Xinxin; Hu, Hongrui; Li, Yang; Wu, Mingzai; Wang, Zhongzhu; Li, Guang; Sun, Zhaoqi; Chen, Changle

    2015-03-01

    Iron oxides/reduced graphene oxide composites were synthesized by facile thermochemical reactions of graphite oxide and FeSO4.7H2O. By adjusting reaction temperature, α-Fe2O3/reduced graphene oxide and Fe3O4/reduced graphene oxide composites can be obtained conveniently. Graphene oxide and reduced graphene oxide sheets were demonstrated to regulate the phase transition from α-Fe2O3 to Fe3O4 via γ-Fe2O3, which was reported for the first time. The hydroxyl groups attached on the graphene oxide sheets and H2 gas generated during the annealing of graphene oxide are believed to play an important role during these phase transformations. These samples showed good electromagnetic wave absorption performance due to their electromagnetic complementary effect. These samples possess much better electromagnetic wave absorption properties than the mixture of separately prepared Fe3O4 with rGO, suggesting the crucial role of synthetic method in determining the product properties. Also, these samples perform much better than commercial absorbers. Most importantly, the great stability of these composites is highly advantageous for applications as electromagnetic wave absorption materials at high temperatures.

  4. Development of ultrasonic thermometry for high-temperature high-resolution temperature profiling applications in LMFBR safety research

    Science.gov (United States)

    Field, M. E.

    1986-05-01

    Ultrasonic thermometry was developed as a high temperature profiling diagnostic for use in the Liquid Metal Fast Breeder Reactor (LMFBR) Debris Coolability Program at Sandia National Laboratories. These instruments were used successfully in the DC series experiments and the D10 experiment. Temperatures approaching 3000 C with spatial resolution of 10 mm and indicated temperature gradients of 700 C/cm were measured. Instruments were operated in molten sodium, molten steel, and molten UO2 environments. Up to 14 measurement zones on a single instrument in molten sodium were used with 12 mm and 15 mm spatial resolution. Hermetically sealed units operating at elevated temperatures were used. Post-test examination revealed very little systematic calibration drifts (less than 10 C) with random drifts occuring with less than 40 C standard deviation in a 10 to 12 mm measured zone. The stability of the system varies from +/- 1 C to +/- 15 C depending on the sensor design constraints for a particular application. Doped tungsten sensors were developed to permit operation of total measurement zone length of 30 cm at temperatures above 2500 C.

  5. Application of High Temperature Corrosion-Resistant Materials and Coatings Under Severe Corrosive Environment in Waste-to-Energy Boilers

    Science.gov (United States)

    Kawahara, Yuuzou

    2007-06-01

    Corrosion-resistant materials (CRMs) and coatings are key technologies to increase power generation efficiency and reduce maintenance in waste-to-energy (WTE) plants. Corrosion environment became severe as steam temperatures have increased. The steam condition of more than 400 °C/3.9 MPa became possible in WTE boilers by using highly durable corrosion-resistant coatings, such as thermal spray of Al/80Ni20Cr alloy, HVOF-sprayed NiCrSiB alloy, Alloy 625 weld overlay for waterwall tubes and also superheater tubes. Also, the use of 310S type stainless steels and high Cr-high Mo-Ni base and high Si-Cr-Ni-Fe alloys have progressed because of a better understanding of corrosion mechanisms. Furthermore, high durability coatings using cermet and ceramic materials were applied to high temperature superheaters. This paper describes the major developments and the application of CRMs and coating technologies in the last 30 years in WTE plants, the corrosion mechanisms of alloys, the deterioration mechanisms of spray coating layers, and future subjects for the development of corrosion-resistant materials and coatings.

  6. Silicon carbide resonant tuning fork for microsensing applications in high-temperature and high G-shock environments

    Institute of Scientific and Technical Information of China (English)

    David R Myers; Kan Bun Cheng; Babak Jamshidi; Robert G Azevedo; Debbie G Senesky; Li Chen; Mehran Mehregany; Muthu B J Wijesundara; Albert P Pisano

    2012-01-01

    We present the fabrication and testing of a silicon carbide (SiC) balanced mass doublended tuning fork that survives harsh environments without compromising the device strain sensitivity and resolution bandwidth. The device features a material stack that survives corrosive environments and enables high-temperature operation. To perform hightemperature testing, a specialized setup was constructed that allows the tuning fork to be characterized using traditional silicon electronics. The tuning fork has been operated at 600°C in the presence of dry steam for short durations. This tuning fork has also been tested to 64 000 G using a hard-launch, soft-catch shock implemented with a light gas gun. However, the device still has a strain sensitivity of 66 Hz/μe and strain resolution of 0. 045 μe in a 10 kHz bandwidth. As such, this balanced-mass double-ended tuning fork can be used to create a variety of different sensors including strain gauges, accelerometers, gyroscopes, and pressure transducers. Given the adaptable fabrication process flow, this device could be useful to micro-electro-mechanical systems (MEMS) designers creating sensors for a variety of different applications.

  7. Facile synthesis of iron oxides/reduced graphene oxide composites: application for electromagnetic wave absorption at high temperature.

    Science.gov (United States)

    Zhang, Lili; Yu, Xinxin; Hu, Hongrui; Li, Yang; Wu, Mingzai; Wang, Zhongzhu; Li, Guang; Sun, Zhaoqi; Chen, Changle

    2015-03-19

    Iron oxides/reduced graphene oxide composites were synthesized by facile thermochemical reactions of graphite oxide and FeSO4 · 7H2O. By adjusting reaction temperature, α-Fe2O3/reduced graphene oxide and Fe3O4/reduced graphene oxide composites can be obtained conveniently. Graphene oxide and reduced graphene oxide sheets were demonstrated to regulate the phase transition from α-Fe2O3 to Fe3O4 via γ-Fe2O3, which was reported for the first time. The hydroxyl groups attached on the graphene oxide sheets and H2 gas generated during the annealing of graphene oxide are believed to play an important role during these phase transformations. These samples showed good electromagnetic wave absorption performance due to their electromagnetic complementary effect. These samples possess much better electromagnetic wave absorption properties than the mixture of separately prepared Fe3O4 with rGO, suggesting the crucial role of synthetic method in determining the product properties. Also, these samples perform much better than commercial absorbers. Most importantly, the great stability of these composites is highly advantageous for applications as electromagnetic wave absorption materials at high temperatures.

  8. Ultra-High Temperature Gratings

    Institute of Scientific and Technical Information of China (English)

    John Canning; Somnath Bandyopadhyay; Michael Stevenson; Kevin Cook

    2008-01-01

    Regenerated gratings seeded by type-Ⅰ gratings are shown to withstand temperatures beyond 1000 ℃. The method of regeneration offers a new approach to increasing temperature resistance of stable fibre Bragg and other gratings. These ultra-high temperature (UHT) gratings extend the applicability of silicate based components to high temperature applications such as monitoring of smelters and vehicle and aircraft engines to high power fibre lasers.

  9. Development of Manufacturing Methods for Low-Cost, High-Temperature Sensors Applicable to Hypersonic Research Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Routine installation and use of high-temperature optical sensors for characterization of advanced materials critical to NASA hypersonic programs are difficult due to...

  10. Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications

    Institute of Scientific and Technical Information of China (English)

    李晨; 谭秋林; 薛晨阳; 张文栋; 李运芝; 熊继军

    2015-01-01

    In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600 ◦C. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor.

  11. Rational mutagenesis by engineering disulphide bonds improves Kluyveromyces lactis beta-galactosidase for high-temperature industrial applications

    Science.gov (United States)

    Rico-Díaz, Agustín; Álvarez-Cao, María-Efigenia; Escuder-Rodríguez, Juan-José; González-Siso, María-Isabel; Cerdán, M. Esperanza; Becerra, Manuel

    2017-01-01

    Kluyveromyces lactis β-galactosidase (Kl-β-Gal) is one of the most important enzymes in the dairy industry. The poor stability of this enzyme limits its use in the synthesis of galactooligosaccharides (GOS) and other applications requiring high operational temperature. To obtain thermoresistant variants, a rational mutagenesis strategy by introducing disulphide bonds in the interface between the enzyme subunits was used. Two improved mutants, R116C/T270C and R116C/T270C/G818C, had increased half-lives at 45 °C compared to Kl-β-Gal (2.2 and 6.8 fold increases, respectively). Likewise, Tm values of R116C/T270C and R116C/T270C/G818C were 2.4 and 8.5 °C, respectively, higher than Kl-β-Gal Tm. Enrichment in enzymatically active oligomeric forms in these mutant variants also increased their catalytic efficiency, due to the reinforcement of the interface contacts. In this way, using an artificial substrate (p-nitrophenyl-β-D-galactopyranoside), the Vmax values of the mutants were ~1.4 (R116C/T270C) and 2 (R116C/T270C/G818C) fold higher than that of native Kl-β-Gal. Using the natural substrate (lactose) the Vmax for R116C/T270C/G818C almost doubled the Vmax for Kl-β-Gal. Validation of these mutant variants of the enzyme for their use in applications that depend on prolonged incubations at high temperatures was achieved at the laboratory scale by monitoring their catalytic activity in GOS synthesis. PMID:28361909

  12. Effect of microstructure on high-temperature mechanical behavior of nickel-base superalloys for turbine disc applications

    Science.gov (United States)

    Sharpe, Heather Joan

    2007-05-01

    Engineers constantly seek advancements in the performance of aircraft and power generation engines, including, lower costs and emissions, and improved fuel efficiency. Nickel-base superalloys are the material of choice for turbine discs, which experience some of the highest temperatures and stresses in the engine. Engine performance is proportional to operating temperatures. Consequently, the high-temperature capabilities of disc materials limit the performance of gas-turbine engines. Therefore, any improvements to engine performance necessitate improved alloy performance. In order to take advantage of improvements in high-temperature capabilities through tailoring of alloy microstructure, the overall objectives of this work were to establish relationships between alloy processing and microstructure, and between microstructure and mechanical properties. In addition, the projected aimed to demonstrate the applicability of neural network modeling to the field of Ni-base disc alloy development and behavior. The first phase of this work addressed the issue of how microstructure varies with heat treatment and by what mechanisms these structures are formed. Further it considered how superalloy composition could account for microstructural variations from the same heat treatment. To study this, four next-generation Ni-base disc alloys were subjected to various controlled heat-treatments and the resulting microstructures were then quantified. These quantitative results were correlated to chemistry and processing, including solution temperature, cooling rate, and intermediate hold temperature. A complex interaction of processing steps and chemistry was found to contribute to all features measured; grain size, precipitate distribution, grain boundary serrations. Solution temperature, above a certain threshold, and cooling rate controlled grain size, while cooling rate and intermediate hold temperature controlled precipitate formation and grain boundary serrations. Diffusion

  13. Development of a new 718-type Ni-Co superalloy family for high temperature applications at 750∘C

    Directory of Open Access Journals (Sweden)

    Fedorova Tatiana

    2014-01-01

    Full Text Available Alloy718 has been used for many years in the aerospace industry due to its unique mechanical properties and good processing characteristics, especially its workability. However, the temperature limit of Alloy718 is about 650 ∘C because of the thermal instability of the main strengthening phase γ′′-Ni3(Nb,Ti,Al. Numerous attempts have been made to develop a new wrought 718-type alloy for high temperature applications. The approach was to increase the stability, i.e. the solvus temperature of the γ′-phase (Tγ′,s. However, this affected workability as the solvus temperature of the δ-phase (Tδ,s did not increase accordingly so that the window for fine grain forging Tδ,s-Tγ′,s became smaller. In this paper the development of a new γ′/γ′-alloy on the basis of Alloy718 is presented, where the microstructure is stable at 800 ∘C, mechanical properties are similar to Alloy718, yet do not deteriorate beyond 650 ∘C, and the forging window is wider than the one of Alloy718, allowing for good workability. This was essentially achieved by the addition of about 17%–30% Co in combination with an Al/Ti-ratio of more than 5.0 and an Al-content of about 1.6%–2.2%. The key role of cobalt is to stabilize the δ-phase, allowing for solvus temperatures in excess of 1100 ∘C. Consequently, the stability of the γ′ -phase can be increased by further addition of aluminium. At the same time the Ti-content is reduced to prevent formation of the η-(Ni,Co3(Ti,Al,Nb phase. Besides discussion of the alloy development concept, information on microstructure evolution and mechanical properties will be given.

  14. Report of the first prototype of non-imaging focusing heliostat and its application in high temperature solar furnace

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.T.; Ismail, Ghazally [Malaysia Univ. of Science and Technology, Inst. of Energy and Environment, Selangor (Malaysia); Chong, K.K.; Lim, C.S.; Lim, B.H.; Tan, B.K. [Malaysia Univ. of Science and Technology, Inst. of Energy and Environment, Selangor (Malaysia); Univ. of Technology Malaysia, Faculty of Electrical Engineering, Johor (Malaysia); Tan, K.K.; Aliman, Omar; Bligh, T.P. [Univ. of Technology Malaysia, Faculty of Electrical Engineering, Johor (Malaysia)

    2002-06-01

    Following the publication on the principle and theory of a newly proposed non-imaging focusing heliostat, this paper presents a report on the design, optical alignment and application of the first prototype heliostat. In the architecture of the first prototype, 25 mirrors, each with a dimension of 40x40 cm, are arranged into five rows and five columns to form a total reflective area of 4 m{sup 2}. The design of the essential part of the first prototype heliostat will be discussed in this paper, which consists of two primary elements; a rotation-elevation system for tracking a mirror support frame which carries 25 mirror facets, and a separate two-axis tracking system for compensating (each second) off-axis aberrations of 24 slave facets relative to the central mirror, which is fixed in the mirror frame. The rotation-elevation system consists of a pedestal supporting a rotational tracking mechanism carrying a U-shaped arm and a second tracking system for tracking a moving frame in elevation. The moving frame carries a central stationary (relative to the frame) mirror, called a master mirror. Slave mirrors are arrayed in five rows and five columns, and eight stepper motors drive the outer four rows and columns relative to the master mirror via a computer programme implementing newly proposed formulas to eliminate the first-order aberration. With a second stage concentrator comprising a small aperture size parabolic mirror (diameter of 60 cm), a cost-effective high temperature solar furnace was constructed. In our experiment, the highest furnace temperature of 3400 deg C has been recorded through the melting of pure tungsten wires. (Author)

  15. A Comparative Analysis of Nature-Inspired Optimization Approaches to 2D Geometric Modelling for Turbomachinery Applications

    Directory of Open Access Journals (Sweden)

    Amir Safari

    2013-01-01

    Full Text Available A vast variety of population-based optimization techniques have been formulated in recent years for use in different engineering applications, most of which are inspired by natural processes taking place in our environment. However, the mathematical and statistical analysis of these algorithms is still lacking. This paper addresses a comparative performance analysis on some of the most important nature-inspired optimization algorithms with a different basis for the complex high-dimensional curve/surface fitting problems. As a case study, the point cloud of an in-hand gas turbine compressor blade measured by touch trigger probes is optimally fitted using B-spline curves. In order to determine the optimum number/location of a set of Bezier/NURBS control points for all segments of the airfoil profiles, five dissimilar population-based evolutionary and swarm optimization techniques are employed. To comprehensively peruse and to fairly compare the obtained results, parametric and nonparametric statistical evaluations as the mathematical study are presented before designing an experiment. Results illuminate a number of advantages/disadvantages of each optimization method for such complex geometries’ parameterization from several different points of view. In terms of application, the final appropriate parametric representation of geometries is an essential, significant component of aerodynamic profile optimization processes as well as reverse engineering purposes.

  16. Turbomachinery Flow Physics and Dynamic Performance

    CERN Document Server

    Schobeiri, Meinhard T

    2012-01-01

    With this second revised and extended edition, the readers have a solid source of information for designing state-of-the art turbomachinery components and systems at hand.   Based on fundamental principles of turbomachinery thermo-fluid mechanics, numerous CFD based calculation methods are being developed to simulate the complex 3-dimensional, highly unsteady turbulent flow within turbine or compressor stages. The objective of this book is to present the fundamental principles of turbomachinery fluid-thermodynamic design process of turbine and compressor components, power generation and aircraft gas turbines in a unified and compact manner. The book provides senior undergraduate students, graduate students and engineers in the turbomachinery industry with a solid background of turbomachinery flow physics and performance fundamentals that are essential for understanding turbomachinery performance and flow complexes.   While maintaining the unifying character of the book structure in this second revised and e...

  17. Electro-magnetic properties and engineering applications of single-domain high temperature superconductor yttrium barium copper oxide

    Science.gov (United States)

    Qu, Dehui

    High temperature superconductors (HTS) exhibit a commonly known Meissner effect, which can cause a unusually strong magnetic repulsion. Using this effect, magnetic bearings have been constructed with 1000 times less friction than that of conventional bearings. The commercialization of the flywheel energy storage device (FESD) could mean cost-savings for the electric power industry. For instance, using a flywheel device, the energy can be generated most efficiently at a steady rate, and meet the high demand in peak daytime hours. Since the magnetic levitation using HTS involves very little friction, only about 0.1 percent of stored energy is lost per hour making electricity consumption most economic. As FESD is to be commercialized in the future, need for more expensive fossil fuel generating plants would be reduced or eliminated. In magnetic levitation using an anisotropic HTS such as YBa2Cu 3Ox, it has been reported that the levitation force is determined by sample geometry and flux pinning strength. Previous studies on critical current density and flux creep have indicated that crystal orientation should have a significant effect on levitation force due to superconducting anisotropy. The underline mechanisms governing the levitation force associated with superconducting anisotropy have not, however, been identified. Finding the crystal orientation dependence of the levitation force is not only of great interest to fundamental studies, but also important for industrial applications. For instance, the levitation force has been found to be one of the key parameters influencing the energy loss in flywheel energy storage. Enhancement of the levitation force has been the main goal in HTS materials development for magnetic bearings. The study of the relationship between levitation force and various materials parameters including crystal orientation, flux pinning strength, and geometry provide valuable information in further optimizing the materials performance in

  18. Calcium aluminate silicate Ca2Al2SiO7 single crystal applicable to piezoelectric sensors at high temperature

    Science.gov (United States)

    Takeda, Hiroaki; Hagiwara, Manabu; Noguchi, Hiroaki; Hoshina, Takuya; Takahashi, Tomoko; Kodama, Nobuhiro; Tsurumi, Takaaki

    2013-06-01

    Ca2Al2SiO7 (CAS) bulk single crystals were grown by the Czochralski method. Material constants of the crystal were determined over the driving temperature range of a typical combustion pressure sensor. The electrical resistivity at 800 °C was found to be of the order of 108 Ωcm. We constructed a measurement system for the direct piezoelectric effect at high temperature, and characterized the crystals in a simulated engine cylinder combustion environment. Output charge signal against applied stress was detected at 700 °C. These observations suggest that CAS crystals are superior candidate materials for high temperature for stress sensing.

  19. Analysis of the thin-film SOI lateral bipolar transistor and optimization of its output characteristics for high-temperature applications

    Science.gov (United States)

    Adriaensen, S.; Flandre, D.

    2002-09-01

    In this paper, we investigate and optimize the static characteristics of NPN lateral bipolar transistors implemented in a thin-film fully-depleted SOI CMOS process for high-temperature analog applications. The basic lateral SOI bipolar device, which shows good behaviour in high-temperature circuits in spite of its relatively poor performances, is firstly described regarding its process and layout parameters. Then the concept of the graded-base bipolar transistor is introduced. This device presents significantly improved output characteristics while preserving standard current gain and CMOS process compatibility. Measurements and simulations are used to demonstrate the improvements of the breakdown voltage and the Early voltage of the bipolar device.

  20. Analysis on application of high temperature ifber sensor%高温光纤传感器应用分析

    Institute of Scientific and Technical Information of China (English)

    赵亚丽

    2016-01-01

    高温光纤传感器在现代各个领域中应用广泛,解决了传统光纤传感器在高温下无法稳定工作的问题。文章对高温光纤传感器的工作原理进行了简述,介绍了其完成热结构温度和应变测试的运行机理,分别介绍了以高温光纤传感器检测飞机进气口温度和排除过山车安全隐患的应用实例,说明了其性能上的优势。%High temperature optical ifber sensor is widely used in various ifelds of modern, which solved the problem that traditional o ptical ifber sensor can not work stably in high temperature. In this paper, the working principle of high temperature optical ifber sensor is brielfy described, temperature and operating mechanism of whose completing the thermal structure and strain testing are introduced. And a case that high temperature optical ifber sensor measured plane air inlet temperature and a case that it eliminated the hidden dangers of roller coaster are separately taken to show its performance advantages.

  1. High-resolution transmission measurements of CO2 at high temperatures for industrial applications

    DEFF Research Database (Denmark)

    Evseev, Vadim; Fateev, Alexander; Clausen, Sønnik

    2012-01-01

    . The spectra have been recorded in a high-temperature flow gas cell and using a Fourier transform infrared (FTIR) spectrometer at a nominal resolution of 0.125 cm-1. The volume fractions of CO2 in the measurements were 1,10 and 100%. The measurements have been validated by comparison with medium...

  2. Self-Propagating High-Temperature Synthesis in the Ti-C-Ni-Mo System on Application of Powerful Ultrasound

    Science.gov (United States)

    Kulak, M. M.; Khina, B. B.

    2014-03-01

    An experimental setup has been developed and a study has been made of the self-propagating high-temperature synthesis in a Ti-C-Ni-Mo system under the conditions of action of ultrasonic vibrations. The influence of the amplitude of ultrasonic vibrations on the combustion rate and temperature and on the phase composition and structure of the derived composite material based on titanium carbide with a metal binder has been determined. The heat-transfer coefficient on the surface of a sample for vibrations at ultrasound frequency has been evaluated. Consideration has been given to possible mechanisms of influence of ultrasonic vibrations on the process of self-propagating high-temperature synthesis. It has been shown that the reduction in the synthesis temperature is due to the cooling of the sample because of the forced convection of the surrounding gas, whereas the change in the structure of the synthesized material is related to the change in the conditions of high-temperature heterogeneous interaction in the wave of self-propagating high-temperature synthesis.

  3. A European project on high temperature metrology for industrial applications; Un proyecto europeo en metrologia de altas temperaturas para aplicaciones industriales

    Energy Technology Data Exchange (ETDEWEB)

    Campo, D. del; Machin, G.

    2013-09-01

    The measurement of temperatures above 1000 degree centigrade is both difficult and yet vital for the success of a wide range of industrial processes; glass and ceramic manufacturing (1100 degree centigrade to 2000 degree centigrade) or refractory metals production (2500+ degree centigrade) are clear examples. Many of these industries require improved process efficiency/control, because of growing environmental concerns (emissions zero waste) and competition from outside the EU. One of the keys to making advances to these drivers is improving process control by improved high temperature measurement. In the frame of the European Metrology Research Program (EMRP), a project named High temperature metrology for industrial applications (HiTeMS) with the overall objective of developing a suite of methods and techniques for improving the measurement of high temperatures in industry has been running since September 2011. This paper gives an overview of the main objectives of the project and the technical activities that are being performed. (Author)

  4. Design and development of NiTi-based precipitation-strengthened high-temperature shape memory alloys for actuator applications

    Science.gov (United States)

    Hsu, Derek Hsen Dai

    As a vital constituent in the field of smart materials and structures, shape memory alloys (SMAs) are becoming ever-more important due to their wide range of commercial and industrial applications such as aircraft couplings, orthodontic wires, and eyeglasses frames. However, two major obstacles preventing SMAs from fulfilling their potential as excellent actuator materials are: 1) the lack of commercially-viable SMAs that operate at elevated temperatures, and 2) the degradation of mechanical properties and shape memory behavior due to thermal cyclic fatigue. This research utilized a thermodynamically-driven systems design approach to optimize the desired properties by controlling the microstructure and processing of high-temperature SMAs (HTSMAs). To tackle the two aforementioned problems with HTSMAs, the introduction of Ni2TiAl coherent nanoprecipitates in a Ni-Ti-Zr/Hf HTSMA matrix is hypothesized to strengthen the martensite phase while simultaneously increasing the transformation temperature. Differential scanning calorimetry (DSC) was used to determine the transformation temperatures and thermal cyclic stability of each alloy. Also, microstructural characterization was performed using X-ray diffraction (XRD), optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atom probe tomography (APT). Lastly, compression testing was used to assess the mechanical behavior of the alloys. From the investigation of the first set of Ni48.5Ti31.5-X Zr20AlX (X = 0, 1, 2, 3) prototype alloys, Al addition was found to decrease the transformation temperatures, decrease the thermal cyclic stability, but also increase the strength due to the nucleation and growth of embrittling NiTi2 and NiTiZr Laves phases. However, the anticipated Heusler phase precipitation did not occur. The next study focused on Ni50Ti30-XHf20Al X (X = 0, 1, 2, 3, 4, 5) prototype alloys which replaced Zr with Hf to avoid the formation of brittle Laves phases

  5. High-Resolution Digital Two-Color PIV for Turbomachinery Flows

    Science.gov (United States)

    Copenhaver, W.; Gogineni, S.; Goss, L.

    1996-11-01

    Turbomachinery flows are inherently unsteady. However, steady design methods are currently used to develop turbomachinery, with the lack of basic understanding of unsteady effects being compensated by use of extensive empirical correlations. Conventional laser anemometry provides quantitative evidence of unsteady effects in turbomachinery but is limited in fully exploring this phenomenon. The PIV technique holds great promise for elucidating unsteady flow mechanisms in turbomachinery if obstacles to its application in a transonic turbomachine can be overcome. Implementation involves critical issues such as tracer seeding and optical access for transmitter and receiver. Initially, an 18-in.-dia. axial fan is used to explore these issues. One optical configuration considered is the fiber-optic fanning light sheet in conjunction with high-power pulsed lasers. Instantaneous velocity measurements are made between blades at different spanwise locations.

  6. Development of an aluminized multi-phase steel with dual phase properties for high temperature corrosion resistance applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahieu, J.; Cooman, B.C. de [Lab. for Iron and Steelmaking, Dept. of Metallurgy and Materials Science, Ghent Univ., Zwijnaarde (Belgium); Maki, J. [Yawata R and D Lab., Nippon Steel Corp. (Japan); Fiorucci, M. [Galvalange Sarl, Dudelange (Luxembourg); Claessens, S. [OCAS NV, Zelzate (Belgium)

    2003-04-01

    A high strength, high Mn, Cr-Mo containing multi-phase steel grade was aluminized with a 90 wt% Al-10 wt% Si alloy coating, using a laboratory hot-dip simulator. The adhesion of the coating to the steel strip was evaluated and the microstructure of the as deposited material was assessed. The coated sheet steel was tested at high temperatures by monitoring the weight gain of the samples and their mechanical properties as a function of time. It was found that the thermal properties of the aluminized sheet were excellent. The analysis of the coating/substrate interface revealed the dissolution of brittle intermetallic phases, explaining the excellent high temperature resistance performance of the Al-Si coating up to temperatures as high as 900 C. In addition, the use of a continuous annealing cycle common in current aluminizing lines, resulted in a dual phase microstructure. (orig.)

  7. Numerical Analysis of a Single Microchannel Within a High-Temperature Hydrogen Heat Exchanger for Beamed Energy Propulsion Applications

    Science.gov (United States)

    2013-07-01

    Conference Paper 3. DATES COVERED (From - To) 14 Jul 2013 – 19 Jul 2013 4. TITLE AND SUBTITLE Numerical Analysis of a Single Microchannel Within a High...propulsion spacecraft. It was found that despite the very small diameter of the microchannels , each design produced extreme temperature...2013, Minneapolis, MN, USA HT2013-17217 DRAFT NUMERICAL ANALYSIS OF A SINGLE MICROCHANNEL WITHIN A HIGH- TEMPERATURE HYDROGEN HEAT EXCHANGER FOR

  8. Cast Aluminum Alloys for High Temperature Applications Using Nanoparticles Al2O3 and Al3-X Compounds (X = Ti, V, Zr)

    Science.gov (United States)

    Lee, Jonathan A.

    2009-01-01

    In this paper, the effect of nanoparticles Al2O3 and Al3-X compounds (X = Ti, V, Zr) on the improvement of mechanical properties of aluminum alloys for elevated temperature applications is presented. These nanoparticles were selected based on their low cost, chemical stability and low diffusions rates in aluminum at high temperatures. The strengthening mechanism at high temperature for aluminum alloy is based on the mechanical blocking of dislocation movements by these nanoparticles. For Al2O3 nanoparticles, the test samples were prepared from special Al2O3 preforms, which were produced using ceramic injection molding process and then pressure infiltrated by molten aluminum. In another method, Al2O3 nanoparticles can also be homogeneously mixed with fine aluminum powder and consolidated into test samples through hot pressing and sintering. With the Al3-X nanoparticles, the test samples are produced as precipitates from in-situ reactions with molten aluminum using conventional permanent mold or die casting techniques. It is found that cast aluminum alloy using nanoparticles Al3-X is the most cost effective method to produce high strength aluminum alloys for high temperature applications in comparison to nanoparticles Al2O3. Furthermore, significant mechanical properties retention in high temperature environment could be achieved with Al3-X nanoparticles, resulting in tensile strength of nearly 3 times higher than most 300- series conventional cast aluminum alloys tested at 600 F.

  9. An experimental insight into the evolution of permeability at high temperatures and applications for shallow conduit and lava dome degassing

    Science.gov (United States)

    Chadderton, Amy; Sammonds, Peter; Meredith, Philip; Smith, Rosanna; Tuffen, Hugh; Gaunt, Elizabeth

    2016-04-01

    Two recent eruptions in Chile, at Chaitén Volcano in 2008-10 and Cordón Caulle in 2011-12, allowed the first detailed observations of rhyolitic activity and provided insights into the evolution of highly silicic eruptions. Both events exhibited simultaneous explosive and effusive activity, with both lava and ash plumes emitted from the same vent [1]. The permeability of fracture networks that act as fluid flow pathways is key to understanding such eruptive behaviour. Here, we report results from a systematic experimental investigation of permeability in volcanic rocks at magmatic temperatures and pressures, in the presence of pore fluids using our newly-developed high-temperature permeability facility. Enhancements to the High Temperature Triaxial Deformation Cell at UCL [2] have enabled us to make permeability measurements on 25mm x 50mm cores at both elevated temperature and elevated hydrostatic pressure [3]. We present results from several suites of permeability measurements on samples of dome dacite from the 2004-08 eruption of Mount St Helens, and rhyolite collected from the lava dome formed during the 2008-10 eruption of Chaitén, Chile. Tests were conducted at temperatures up to 900oC and under an effective pressure of 5 MPa, using the steady-state flow technique. Samples were cooled to room temperature between each high temperature test, and the permeability of each sample was re-measured before heating to the next temperature increment in the series. Additional longer duration high temperature tests were also conducted to investigate the development of a permeable network at high temperatures over time. The results show a complex permeability evolution that includes a reduction in permeability by approximately 3 orders of magnitude up to 600oC. Together with thermal cracking tests, AE data and SEM/thin section analysis these new experimental permeability results are applied to enhance our understanding of the complex issue of shallow conduit and lava

  10. Solid Lubricants for Oil-Free Turbomachinery

    Science.gov (United States)

    DellaCorte, Christopher

    2005-01-01

    Recent breakthroughs in gas foil bearing solid lubricants and computer based modeling has enabled the development of revolulionary Oil-Free turbomachinery systems. These innovative new and solid lubricants at low speeds (start-up and shut down). Foil bearings are hydrodynamic, self acting fluid film bearings made from thin, flexible sheet metal foils. These thin foils trap a hydrodynamic lubricating air film between their surfaces and moving shaft surface. For low temperature applications, like ainrafl air cycle machines (ACM's), polymer coatings provide important solid lubrication during start-up and shut down prior to the development of the lubricating fluid film. The successful development of Oil-Free gas turbine engines requires bearings which can operate at much higher temperatures (greater than 300 C). To address this extreme solid lubrication need, NASA has invented a new family of compostie solid lubricant coatings, NASA PS300.

  11. Microstructure and properties of an HfB{sub 2}-SiC composite for ultra high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Monteverde, F.; Bellosi, A. [National Research Council, Institute of Science and Technology for Ceramics, Via Granarolo 64, 48018 Faenza (Italy)

    2004-05-01

    An ultra-high-temperature ceramic (UHTC) based on HfB{sub 2} was produced. The microstructure consisted of fine and regular diboride grains (2 {mu}m average size), with SiC particulate distributed intergranularly, not rarely in clustered formation, and low levels of secondary phases were identified. The resulting thermo-mechanical properties proved interesting results for microhardness and fracture toughness. The microstructural alteration experienced within the explored temperature range renders the material unsuitable for service in extreme conditions of temperature and pressure. (Abstract Copyright [2004], Wiley Periodicals, Inc.)

  12. APPLICATION OF THE UNIFIED STATISTICAL MATERIAL DATABASE FOR DESIGN AND LIFE/RISK ASSESSMENT OF HIGH TEMPERATURE COMPONENTS

    Institute of Scientific and Technical Information of China (English)

    K.Fujiyama; T.Fujiwara; Y.Nakatani; K.Saito; A.Sakuma; Y.Akikuni; S.Hayashi; S.Matsumoto

    2004-01-01

    Statistical manipulation of material data was conducted for probabilistic life assessment or risk-based design and maintenance for high temperature components of power plants. To obtain the statistical distribution of material properties, dominant parameters affecting material properties are introduced into normalization of statistical variables. Those parameters are hardness, chemical composition, characteristic microstructural features and so on. Creep and fatigue properties are expressed by normalized parameters and the unified statistical distributions are obtained. These probability distribution functions show good coincidence statistically with the field database of steam turbine components. It was concluded that the unified statistical baseline approach is useful for the risk management of components in power plants.

  13. New concept of composite strengthening in Co-Re based alloys for high temperature applications in gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Mukherji, D.; Roesler, J.; Fricke, T.; Schmitz, F. [Technische Univ. Braunschweig (DE). Inst. fuer Werkstoffkunde (IfW); Piegert, S. [Siemens AG, Berlin (DE). Energy Sector (F PR GT EN)

    2010-07-01

    High temperature material development is mainly driven by gas turbine needs. Today, Ni-based superalloys are the dominant material class in the hot section of turbines. Material development will continue to push the maximum service temperature of Ni-superalloys upwards. However, this approach has a fundamental limit and can not be sustained indefinitely, as the Ni-superalloys are already used very close to their melting point. Within the frame work of a DFG Forschergruppe program (FOR 727) - ''Beyond Ni-base Superalloys'' - Co-Re based alloys are being developed as a new generation of high temperature materials that can be used at +100 C above single crystal Ni-superalloys. Along with other strengthening concepts, hardening by second phase is explored to develop a two phase composite alloy. With quaternary Co-Re-Cr-Ni alloys we demonstrate this development concept, where Co{sub 2}Re{sub 3}-type {sigma} phase is used in a novel way as the hardening phase. Thermodynamic calculation was used for designing model alloy compositions. (orig.)

  14. Construction and in-situ characterisation of high-temperature fixed point cells devoted to industrial applications

    Directory of Open Access Journals (Sweden)

    Sadli Mohamed

    2014-01-01

    Full Text Available Among the activities of the European Metrology Research Programme (EMRP project HiTeMS one work package is devoted to the development and testing of industrial solutions for long-standing temperature measurement problems at the highest temperatures. LNE-Cnam, NPL, TUBITAK-UME have worked on the design of high temperature fixed points (HTFP suitable for in-situ temperature monitoring to be implemented in the facilities of CEA (Commissariat à l’énergie atomique et aux énergies alternatives. Several high temperature fixed point cells were constructed in these three national metrology institutes (NMIs using a rugged version of cells based on the hybrid design of the laboratory HTFP developed and continuously improved at LNE-Cnam during the last years. The fixed points of interest were Co-C, Ru-C and Re-C corresponding to melting temperatures of 1324 °C, 1953 °C and 2474 °C respectively. The cells were characterised at the NMIs after their construction. Having proved robust enough, they were transported to CEA and tested in an induction furnace and cycled from room temperature to temperatures much above the melting temperatures (> +400 °C with extremely high heating and cooling rates (up to 10 000 K/h. All the cells withstood the tests and the melting plateaus could be observed in all cases.

  15. A Passive Pressure Sensor Fabricated by Post-Fire Metallization on Zirconia Ceramic for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Tao Luo

    2014-09-01

    Full Text Available A high-temperature pressure sensor realized by the post-fire metallization on zirconia ceramic is presented. The pressure signal can be read out wirelessly through the magnetic coupling between the reader antenna and the sensor due to that the sensor is equivalent to an inductive-capacitive (LC resonance circuit which has a pressure-sensitive resonance frequency. Considering the excellent mechanical properties in high-temperature environment, multilayered zirconia ceramic tapes were used to fabricate the pressure-sensitive structure. Owing to its low resistivity, sliver paste was chosen to form the electrical circuit via post-fire metallization, thereby enhancing the quality factor compared to sensors fabricated by cofiring with a high-melting-point metal such as platinum, tungsten or manganese. The design, fabrication, and experiments are demonstrated and discussed in detail. Experimental results showed that the sensor can operate at 600 °C with quite good coupling. Furthermore, the average sensitivity is as high as 790 kHz/bar within the measurement range between 0 and 1 Bar.

  16. Magnetic sensor with silicon on insulator structure for high temperature applications; SOI kozo wo mochiita koon`yo jiki sensor

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Y.; Kawai, H.; Terada, T.; Kawahito, S.; Ishida, M.; Nakamura, T. [Toyohashi University of Technology, Aichi (Japan)

    1996-09-20

    To enable stable magnetic measurement in high temperature surroundings, a Hall cell of the SOI structure (with a single-crystal Si layer formed on an insulating film) was experimentally fabricated, and its characteristics as a magnetic sensor were examined. This element can be mass-produced by use of the current semiconductor manufacturing technology. In the conventional method of element isolation using the pn-junction, backward leak currents across the pn-junction grow large at high temperatures, reducing sensitivity and increasing offset voltage (the Hall voltage at zero magnetic field) to disable the elements. Under the circumstances, an SOI structure in which elements are isolated by an SiO2 film were studied. Sensitivity and temperature characteristics are dependent on donor concentration. But there is a relationship of trade-off between sensitivity and the usable temperature range, and this means that a donor concentration fit for the given purpose needs be chosen. To inhibit the generation of the offset voltage, Hall element shapes and chip bonding methods were studied, and a magnetic sensor with an offset variation not more than {plus_minus}3mV was obtained. In an SOI magnetic sensor, the temperature range in which sensitivity remains constant expands as donor concentration is enhanced, and this permits the use of the SOI magnetic sensor in higher-temperature operations. 6 refs., 13 figs., 1 tab.

  17. The Development of an INL Capability for High Temperature Flow, Heat Transfer, and Thermal Energy Storage with Applications in Advanced Small Modular Reactors, High Temperature Heat Exchangers, Hybrid Energy Systems, and Dynamic Grid Energy Storage C

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xiaodong [The Ohio State Univ., Columbus, OH (United States); Zhang, Xiaoqin [The Ohio State Univ., Columbus, OH (United States); Kim, Inhun [The Ohio State Univ., Columbus, OH (United States); O' Brien, James [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-10-01

    The overall goal of this project is to support Idaho National Laboratory in developing a new advanced high temperature multi fluid multi loop test facility that is aimed at investigating fluid flow and heat transfer, material corrosion, heat exchanger characteristics and instrumentation performance, among others, for nuclear applications. Specifically, preliminary research has been performed at The Ohio State University in the following areas: 1. A review of fluoride molten salts’ characteristics in thermal, corrosive, and compatibility performances. A recommendation for a salt selection is provided. Material candidates for both molten salt and helium flow loop have been identified. 2. A conceptual facility design that satisfies the multi loop (two coolant loops [i.e., fluoride molten salts and helium]) multi purpose (two operation modes [i.e., forced and natural circulation]) requirements. Schematic models are presented. The thermal hydraulic performances in a preliminary printed circuit heat exchanger (PCHE) design have been estimated. 3. An introduction of computational methods and models for pipe heat loss analysis and cases studies. Recommendations on insulation material selection have been provided. 4. An analysis of pipe pressure rating and sizing. Preliminary recommendations on pipe size selection have been provided. 5. A review of molten fluoride salt preparation and chemistry control. An introduction to the experience from the Molten Salt Reactor Experiment at Oak Ridge National Laboratory has been provided. 6. A review of some instruments and components to be used in the facility. Flowmeters and Grayloc connectors have been included. This report primarily presents the conclusions drawn from the extensive review of literatures in material selections and the facility design progress at the current stage. It provides some useful guidelines in insulation material and pipe size selection, as well as an introductory review of facility process and components.

  18. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR program, TRS Technologies has developed several new dielectrics for high temperature applications including signal conditioning, filtering and energy...

  19. High temperature interfacial superconductivity

    Science.gov (United States)

    Bozovic, Ivan [Mount Sinai, NY; Logvenov, Gennady [Port Jefferson Station, NY; Gozar, Adrian Mihai [Port Jefferson, NY

    2012-06-19

    High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator (La.sub.2CuO.sub.4) and a metal (La.sub.1-xSr.sub.xCuO.sub.4), neither of which is superconducting per se, is described. Depending upon the layering sequence of the bilayers, T.sub.c may be either .about.15 K or .about.30 K. This highly robust phenomenon is confined to within 2-3 nm around the interface. After exposing the bilayer to ozone, T.sub.c exceeds 50 K and this enhanced superconductivity is also shown to originate from a 1 to 2 unit cell thick interfacial layer. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T.sub.c phases and to significantly enhance superconducting properties in other superconductors. The superconducting interface may be implemented, for example, in SIS tunnel junctions or a SuFET.

  20. High temperature polymer matrix composites

    Science.gov (United States)

    Serafini, Tito T. (Editor)

    1987-01-01

    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) Characterization; (4) environmental effects; and (5) applications.

  1. Preparation and Photocatalytic Application of High Temperature Stabilized ZrSiO4@TiO2 Hybrid Nanostructure

    Institute of Scientific and Technical Information of China (English)

    PENG Cheng; FANG Peiyu; ZENG Zhichao; Lü Ming; WU Jianqing

    2014-01-01

    A new ZrSiO4@TiO2 hybrid nanostructure was prepared by a heterogeneous flocculation method. Phytic acid was introduced to modify the surface charging of the components for hybrid assembly. The obtained powder was coated on ceramic tiles and fired at 900 ℃ to fabricate photocatalytic ceramic. Experimental results show that anatase TiO2 in the composite powder has high thermal stability until 1 200℃. ZrSiO4 matrix prevents the mass transfer of anatase TiO2 at high temperature and greatly retards the phase transition of anatase to rutile. Besides, the photocatalytic ceramic shows apparent activities for the degradation of methyl orange under ultra-violet irradiation.

  2. Gate-all-around OTA`s for rad-hard and high-temperature analog applications

    Energy Technology Data Exchange (ETDEWEB)

    Vandooren, A.; Colinge, J.P. [Univ. of California, Davis, CA (United States). Dept. of Electrical and Computer Engineering; Flandre, D. [Univ. Catholique de Louvain, Louvain-La-Neuve (Belgium). Lab. de Microelectronique

    1999-08-01

    Performance of operational transconductance amplifiers (OTA`s) fabricated in the gate-all-around SOI technology is described at elevated temperature and after total dose irradiation. Design guidelines using two analog parameters (early voltage and transconductance to drain current ratio) are proposed for correct operation in these two different harsh environments. The design methodology using the two analog parameters of interest is proposed and applied to the specific case of the GAA technology. The temperature and dose dependence of the two above design parameters are then presented. Two different OTA architectures are considered: a single-stage amplifier and a folded cascode amplifier. Experimental results obtained separately for each environment are discussed. High-temperature measurements were performed up to 300 C, while total dose measurements were obtained for doses up to 15 Mrad(Si) total dose of gamma rays from a {sup 60}Co source.

  3. A theory of density-of-states effective masses in heavily doped silicon at high temperatures and its applications

    Science.gov (United States)

    Van Cong, H.

    2007-01-01

    A theory of density-of-states effective masses in the n(p)-type heavily doped silicon at high temperatures, T, was developed, taking into account the effects of nonparabolicity in the band and Fermi-Dirac statistics. It was applied to determine the intrinsic carrier density at 200⩽ T (K)⩽500 accurate to within 4.8%, and at 300 K semi-empirical forms for band gap narrowing (BGN) and apparent BGN with an accuracy of 17% and for optical gap with a precision of 1%, giving rise to a satisfactory description of both electrical and optical data. Furthermore, at 280⩽ T (K)⩽400, the BGN can be assumed to be T-independent, with a precision of 8.8%.

  4. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  5. Gallium phosphide high temperature diodes

    Science.gov (United States)

    Chaffin, R. J.; Dawson, L. R.

    1981-01-01

    High temperature (300 C) diodes for geothermal and other energy applications were developed. A comparison of reverse leakage currents of Si, GaAs, and GaP was made. Diodes made from GaP should be usable to 500 C. A Liquid Phase Epitaxy (LPE) process for producing high quality, grown junction GaP diodes is described. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run. These LPE wafers were cut into die and metallized to make the diodes. These diodes produce leakage currents below ten to the -9th power A/sq cm at 400 C while exhibiting good high temperature rectification characteristics. High temperature life test data is presented which shows exceptional stability of the V-I characteristics.

  6. Turbomachinery for the air management and energy recovery in fuel cell gas turbine hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Traverso, A.; Magistri, L.; Massardo, A.F. [DIMSET (TPG), University of Genoa, Via Montallegro 1, 16145, Genoa (Italy)

    2010-02-15

    High temperature fuel cells (MCFCs and SOFCs) can operate at atmospheric or pressurised conditions. In both cases, system performance can be significantly improved when the fuel cells are integrated with proper devices, which are designed to provide the necessary air inlet conditions and to recover the exhaust gas energy. This paper presents a review of modelling and design issues for the integration of turbomachinery with the fuel cell system, because turbomachinery is the most promising technology for coping with the high temperature fuel cell requirements. Since the gas turbine expander performance is significantly influenced by exhausts compositions, analytical approach is undertaken for properly modelling composition influence on expander performance, and results are presented to demonstrate the quantitative influence of the system parameters on the performance. The analysis covers the three main aspects of performance evaluation: the on-design, the off-design and, as a final mention, the control of the fuel cell hybrid systems. (author)

  7. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Lamichhane, Ranjan [APEI, Inc.; Shepherd, Paul [APEI, Inc.; Glover, Michael [APEI, Inc.

    2014-01-01

    This paper presents a high-temperature capable intelligent power module that contains SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter (Fig. 1) to determine the performance of the module in a system level application. The converter was operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The peak efficiency was found to be 97.5% at 2.9 kW.

  8. High-temperature hydrogenation of pure and silver-decorated titanate nanotubes to increase their solar absorbance for photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Plodinec, Milivoj [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Gajović, Andreja, E-mail: gajovic@irb.hr [Ruđer Bošković Institute, Bijenička 54, HR-1002 Zagreb (Croatia); Jakša, Gregor; Žagar, Kristina; Čeh, Miran [Institute Jožef Stefan, Jamova 39, 1000 Ljubljana (Slovenia)

    2014-04-05

    Graphical abstract: The aim of the work is to study how annealing in a reducing atmosphere of titanate nanotubes (TiNT) and Ag decorated titanate nanotubes (TiNT@Ag) influenced on their structure, morphology, phase transitions, UV–ViS-NIR absorbance and photocatalytic activity. An increase of photocatalytic activity after a heat treatment in a reducing atmosphere was observed in the TiNT and TiNT@Ag. We found that the hydrogenated TiNT@Ag samples (TiNT@Ag-HA) had a two-times higher photodegradation impact on the caffeine than the TiNT samples, which is a consequence of the increased absorption of visible light and the synergetic effects between the silver and the TiO{sub 2} nanoparticles that increase the efficiency of the formation of electron–hole pairs and the charge transfer to the surface of the nanoparticles. -- Highlights: • Titanate nanotubes with and without Ag nanoparticles were hydrogenated at 550 °C. • TiO{sub 2} nanostructures obtained by hydrogenation have core–shell structure. • Hydrogenated samples show absorption in the visible spectral region. • Hydrogenated Ag decorated sample show stronger absorption in visible than in UV. • Photocatalytic efficiency is improved by hydrogenation and by Ag nanoparticles. -- Abstract: Titanate nanotubes (TiNTs) and silver-decorated titanate nanotubes (TiNTs@Ag) were synthesized using the hydrothermal method. In the decorated nanotubes the silver particles were obtained by the photoreduction of AgNO{sub 3} under UV light. Pure and Ag-decorated nanotubes were high-temperature heat treated at 550 °C in a hydrogen atmosphere and the “core–shell”-structured TiO{sub 2} nanoparticles were formed. For the structural characterization of all the titanate nanostructures we used conventional and analytical transmission electron microscopy (TEM) techniques, X-ray diffraction (XRD) and Raman spectroscopy. The Ag-decorated titanate nanostructures were additionally studied by X-ray photo

  9. Cerâmicas porosas para aplicação em altas temperaturas Porous ceramics for high temperature applications

    Directory of Open Access Journals (Sweden)

    M. O. C. Villas Bôas

    2007-12-01

    Full Text Available Com o objetivo de reduzir o consumo energético, tem crescido o uso de cerâmicas refratárias porosas como isolantes térmicos para altas temperaturas. Entre as técnicas comumente empregadas na produção desses materiais (como a adição de surfactante e incorporação de orgânicos, destaca-se aquela baseada na geração de poros por meio de transformações de fase. Comparada às outras técnicas, esse processo se mostra bastante simples e sem geração de voláteis tóxicos. Neste trabalho, essa técnica foi utilizada para produzir porosos por meio da decomposição de hidróxidos de alumínio e alumínio-magnésio, e da posterior reação de espinelização, que os estabiliza e impede sua densificação acima de 1000 ºC. Verificou-se que o uso de hidróxidos complexos resulta em maior volume de poros, resistência mecânica e refratariedade que sua utilização isolada.In order to reduce the energy consumption, the use of porous refractory ceramics as high-temperature insulating materials has grown significantly. Among the techniques employed in the production of these materials, such as the addition of foam and organic compounds, the generation of pores by phase transformation presents great technological interest, due to its easy processing route and lack of toxic volatiles. In the present work, this technique was employed to produce porous ceramics by the decomposition of aluminum and aluminum-magnesium hydroxides. The in-situ spinelization reaction reduces the densification at high temperatures. It was verified that the use of complex hydroxides generates greater porosity, mechanical strength and refractoriness.

  10. High-Temperature Optical Sensor

    Science.gov (United States)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  11. Minnowbrook V: 2006 Workshop on Unsteady Flows in Turbomachinery

    Science.gov (United States)

    LaGraff, John E.; Ashpis, David E.; Oldfield, Martin L. G.; Gostelow, J. Paul

    2006-01-01

    This CD-ROM contain materials presented at the Minnowbrook V 2006 Workshop on Unsteady Flows in Turbomachinery, held at the Syracuse University Minnowbrook Conference Center, New York, on August 20-23, 2006. The workshop organizers were John E. LaGraff (Syracuse University), Martin L.G. Oldfield (Oxford University), and J. Paul Gostelow (University of Leicester). The workshop followed the theme, venue, and informal format of four earlier workshops: Minnowbrook I (1993), Minnowbrook II (1997), Minnowbrook III (2000), and Minnowbrook IV (2003). The workshop was focused on physical understanding of unsteady flows in turbomachinery, with the specific goal of contributing to engineering application of improving design codes for turbomachinery. The workshop participants included academic researchers from the United States and abroad and representatives from the gas-turbine industry and U.S. Government laboratories. The physical mechanisms discussed were related to unsteady wakes, active flow control, turbulence, bypass and natural transition, separation bubbles and turbulent spots, modeling of turbulence and transition, heat transfer and cooling, surface roughness, unsteady CFD, and DNS. This CD-ROM contains copies of the viewgraphs presented, organized according to the workshop sessions. Full-color viewgraphs and animations are included. The workshop summary and the plenary discussion transcripts clearly highlight the need for continued vigorous research in the technologically important area of unsteady flows in turbomachines.

  12. [Iodine concentration in ultra-high temperature pasteurized cow's milk. Applications in clinical practice and in community nutrition].

    Science.gov (United States)

    Arrizabalaga, Juan José; Jalón, Mercedes; Espada, Mercedes; Cañas, Mercedes; Latorre, Pedro María

    2015-07-20

    Changes to dairy cow feeding have made milk a very important food source of iodine in several European countries and in USA. We aimed to measure the iodine content in ultra-high temperature (UHT) milk, the most widely consumed milk in Spain and in the south-west of Europe. Every month, throughout 2008, UHT milk samples of commercial brands available in Vitoria-Gasteiz (Basque Country, Spain) were collected and their iodine content was determined using high-performance liquid chromatography, according to official method 992.22 of the Association of Official Analytical Chemists International. The average (SD) iodide content and median (P25-P75) of standard UHT milk samples (n=489) were 197.6 (58.1) and 190 (159-235) μg/L, respectively. There were no significant differences between the iodide content in whole, semi-skimmed and skimmed milk (P=.219). The average iodide concentration and median in organic UHT milk (n=12) were 56.4 (8.6) and 55 (50.5-61.5) μg/L, figures that are much lower than those found in standard milk (P<.0001). Standard UHT milk available in our food-retailing outlets constitutes a very important source of iodine. One glass of standard UHT milk (200-250mL) provides an average amount of 50μg of iodine. This amount represents around 50% of the iodine intake recommended during childhood or 20% of the iodine intake recommended for pregnant and lactating women. Copyright © 2013 Elsevier España, S.L.U. All rights reserved.

  13. One-step chemical synthesis of ZnO/graphene oxide molecular hybrids for high-temperature thermoelectric applications.

    Science.gov (United States)

    Chen, Dongsheng; Zhao, Yan; Chen, Yani; Wang, Biao; Chen, Haiyan; Zhou, Jun; Liang, Ziqi

    2015-02-11

    ZnO as high-temperature thermoelectric material suffers from high lattice thermal conductivity and poor electrical conductivity. Al is often used to n-dope ZnO to form Zn1-xAlxO (AZO). Owing to very limited Al solubility (less than 2 atom %) in AZO, however, electrical conductivity is difficult to improve further. Moreover, such a low concentration of Al dopants can hardly reduce the thermal conductivity. Here, we propose slightly adding chemically reduced graphene oxides (rGOs) to AZO in various contents to modulate the carrier concentration and simultaneously optimize the electrical and thermal conductivities. Such nanocomposites with rGO embedded in AZO matrix are formed on the molecular level by one-step solution chemistry method. No obvious changes are found in crystalline structures of AZO after introducing rGOs. The rGO inclusions are shown to uniformly mix the AZO matrix that consists of compacted nanoparticles. In such AZO/rGO hybrids, Zn2+ is captured by the rGO, releasing extra electrons and thus increasing electron density, as confirmed by Hall measurements. The phonon-boundary scattering at the interface between AZO and rGO remarkably reduces the lattice thermal conductivity. Therefore, a respectable thermoelectric figure of merit of 0.28 at 900 °C is obtained in these nanocomposites at the rGO content of 1.5 wt %, which is 8 times larger than that of pure ZnO and 60% larger than that of alloyed AZO. This work demonstrates a facile wet chemistry route to produce nanostructured thermoelectric composites in which electrical conductivity can be greatly increased while largely lowering thermal conductivity, collectively enhancing the thermoelectric performance.

  14. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...... input to the cell then hydrogen is produced giving syngas. This syngas can then be further reacted to form hydrocarbon fuels and chemicals. Operating at high temperature gives much higher efficiencies than can be achieved with low temperature electrolysis. Current state of the art SOECs utilise a dense...

  15. Computer Aided Multi-scale Design of SiC-Si3N4 Nanoceramic Composites for High-Temperature Structural Applications

    Energy Technology Data Exchange (ETDEWEB)

    Vikas Tomer; John Renaud

    2010-08-31

    It is estimated that by using better and improved high temperature structural materials, the power generation efficiency of the power plants can be increased by 15% resulting in significant cost savings. One such promising material system for future high-temperature structural applications in power plants is Silicon Carbide-Silicon Nitride (SiC-Si{sub 3}N{sub 4}) nanoceramic matrix composites. The described research work focuses on multiscale simulation-based design of these SiC-Si{sub 3}N{sub 4} nanoceramic matrix composites. There were two primary objectives of the research: (1) Development of a multiscale simulation tool and corresponding multiscale analyses of the high-temperature creep and fracture resistance properties of the SiC-Si{sub 3}N{sub 4} nanocomposites at nano-, meso- and continuum length- and timescales; and (2) Development of a simulation-based robust design optimization methodology for application to the multiscale simulations to predict the range of the most suitable phase morphologies for the desired high-temperature properties of the SiC-Si{sub 3}N{sub 4} nanocomposites. The multiscale simulation tool is based on a combination of molecular dynamics (MD), cohesive finite element method (CFEM), and continuum level modeling for characterizing time-dependent material deformation behavior. The material simulation tool is incorporated in a variable fidelity model management based design optimization framework. Material modeling includes development of an experimental verification framework. Using material models based on multiscaling, it was found using molecular simulations that clustering of the SiC particles near Si{sub 3}N{sub 4} grain boundaries leads to significant nanocomposite strengthening and significant rise in fracture resistance. It was found that a control of grain boundary thicknesses by dispersing non-stoichiometric carbide or nitride phases can lead to reduction in strength however significant rise in fracture strength. The

  16. Global dynamics of shaft lines of turbo-machineries coupled to surrounding fluids: application to the case of fluid sheets; Dynamique globale des lignes d'arbres de turbomachines couplees aux fluides environnants: application au cas des lames fluides

    Energy Technology Data Exchange (ETDEWEB)

    Lornage, D.

    2001-12-15

    Shaft lines of turbo-machineries have to stand increasing reliability, efficiency and safety requirements. A precise modeling of the rotating parts with all possible coupling has become necessary. In this context, this work aims to develop a global modeling of rotating wheel/shaft system inside a surrounding fluid in order to foresee its dynamical behaviour. The use and advantage of Eulerian, Lagrangian and mixed (arbitrary Lagrangian Eulerian - ALE) formulations is recalled first. A bibliographic synthesis of the classical techniques used in structure mechanics and of coupling techniques for rotating machines is presented. The coupling technique retained is presented. It uses fluid and structure models independently developed and validated. The structure domain is discretized by the finite-element method. The fluid domain is discretized by the finite-difference method taking into consideration the hypotheses linked with thin films. A modal base projection combined with a mesh at the fluid-structure interface allows an efficient, adaptable and evolutive coupling. Finally, the method is applied to 3 test-cases. The first two ones comprise a shaft/disc system coupled to a fluid sheet between the disc and the casing and to an hydrodynamic bearing. Both cases allow a first validation of the coupling method. The third case aims to study a structure closer to a real system made of a shaft and a wheel coupled to a fluid sheet between a flange and a casing. These three applications allow to show the trends linked with the fluid effects and the coupling between the flexible sub-parts of the structure. (J.S.)

  17. Synthesis, processing and characterization of ZrB (suíndice 2)-based ultra high temperature ceramics (UHTC) for aerospace applications

    OpenAIRE

    Mínguez López, Pablo José

    2009-01-01

    The high melting temperature of ultra-high temperature ceramics (UHTCs) makes ZrB2-based composites potential candidates for aerospace applications. Full densification of these composites faces major challenge due to the strong covalent bonding and the high-melting point, although with additions of SiC, ZrC, MoSi2, etc. densification can be achieved at reasonable temperatures. The present work investigates the preparation and analysis of ZrB2/SiC (20vol %) composites with different polytypes ...

  18. Analysis of turbomachineries by means of the application of the SMDTurbo system; Analisis de turbomaquinas mediante la aplicacion del sistema SMDTurbo

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga, Helen; Garcia, Ernesto; Bernabe, Jose; Aboites, Fernando [CIATEQ, A.C., Queretaro (Mexico)

    2007-11-15

    In this paper is presented an integral system in experimental phase developed by CIATEQ for the monitoring and acquisition of involved physical variables in the turbo-machinery analysis. The system has been denominated SMDTurbo (System of Monitoring and Diagnosis for Turbo machinery) and its purpose is to realize a diagnosis (on the basis of mathematical and graphical tools) of the performance of the turbo machinery through the measurement of variables such as pressure, temperature and vibration. The obtained data from these elements is used for its later processing of analysis and diagnosis by means of specialized software with which the performance of the turbo machinery will be able to be performed (TM). Preliminary results of the proposal are presented. [Spanish] En este trabajo se presenta un sistema integral en fase experimental desarrollado por CIATEQ para el monitoreo y adquisicion de variables fisicas involucradas en el analisis de turbomaquinaria. El sistema se ha denominado SMDTuro (Sistema de Monitoreo y Diagnostico para Turbomaquinaria) y tiene como proposito realizar un diagnostico (en base a herramientas matematicas y graficas) del rendimiento de la turbomaquina a traves de la medicion de variables como presion, tempreratura y vibracion. La informacion obtenida de estos elementos se utiliza para su posterior proceso de analisis y diagnostico mediante un software especializado con el cual se podra realizar el rendimiento de la turbomaquinaria (TM). Se presentan resultados preliminares de la propuesta.

  19. Development and applications of methodologies for the neutronic design of the Pebble Bed Advanced High Temperature Reactor (PB-AHTR)

    Science.gov (United States)

    Fratoni, Massimiliano

    This study investigated the neutronic characteristics of the Pebble Bed Advanced High Temperature Reactor (PB-AHTR), a novel nuclear reactor concept that combines liquid salt (7LiF-BeF2---flibe) cooling and TRISO coated-particle fuel technology. The use of flibe enables operation at high power density and atmospheric pressure and improves passive decay-heat removal capabilities, but flibe, unlike conventional helium coolant, is not transparent to neutrons. The flibe occupies 40% of the PB-AHTR core volume and absorbs ˜8% of the neutrons, but also acts as an effective neutron moderator. Two novel methodologies were developed for calculating the time dependent and equilibrium core composition: (1) a simplified single pebble model that is relatively fast; (2) a full 3D core model that is accurate and flexible but computationally intensive. A parametric analysis was performed spanning a wide range of fuel kernel diameters and graphite-to-heavy metal atom ratios to determine the attainable burnup and reactivity coefficients. Using 10% enriched uranium ˜130 GWd/tHM burnup was found to be attainable, when the graphite-to-heavy metal atom ratio (C/HM) is in the range of 300 to 400. At this or smaller C/HM ratio all reactivity coefficients examined---coolant temperature, coolant small and full void, fuel temperature, and moderator temperature, were found to be negative. The PB-AHTR performance was compared to that of alternative options for HTRs, including the helium-cooled pebble-bed reactor and prismatic fuel reactors, both gas-cooled and flibe-cooled. The attainable burnup of all designs was found to be similar. The PB-AHTR generates at least 30% more energy per pebble than the He-cooled pebble-bed reactor. Compared to LWRs the PB-AHTR requires 30% less natural uranium and 20% less separative work per unit of electricity generated. For deep burn TRU fuel made from recycled LWR spent fuel, it was found that in a single pass through the core ˜66% of the TRU can be

  20. Design and evaluation of a high temperature/pressure supercritical carbon dioxide direct tubular receiver for concentrating solar power applications

    Science.gov (United States)

    Ortega, Jesus Daniel

    This work focuses on the development of a solar power thermal receiver for a supercritical-carbon dioxide (sCO2), Brayton power-cycle to produce ~1 MWe. Closed-loop sCO2 Brayton cycles are being evaluated in combination with concentrating solar power to provide higher thermal-to-electric conversion efficiencies relative to conventional steam Rankine cycles. High temperatures (923--973 K) and pressures (20--25 MPa) are required in the solar receiver to achieve thermal efficiencies of ~50%, making concentrating solar power (CSP) technologies a competitive alternative to current power generation methods. In this study, the CSP receiver is required to achieve an outlet temperature of 923 K at 25 MPa or 973 K at 20 MPa to meet the operating needs. To obtain compatible receiver tube material, an extensive material review was performed based the ASME Boiler and Pressure Vessel Code, ASME B31.1 and ASME B313.3 codes respectively. Subsequently, a thermal-structural model was developed using a commercial computational fluid (CFD) dynamics and structural mechanics software for designing and analyzing the tubular receiver that could provide the heat input for a ~2 MWth plant. These results were used to perform an analytical cumulative damage creep-fatigue analysis to estimate the work-life of the tubes. In sequence, an optical-thermal-fluid model was developed to evaluate the resulting thermal efficiency of the tubular receiver from the NSTTF heliostat field. The ray-tracing tool SolTrace was used to obtain the heat-flux distribution on the surfaces of the receiver. The K-ω SST turbulence model and P-1 radiation model used in Fluent were coupled with SolTrace to provide the heat flux distribution on the receiver surface. The creep-fatigue analysis displays the damage accumulated due to the cycling and the permanent deformation of the tubes. Nonetheless, they are able to support the required lifetime. The receiver surface temperatures were found to be within the safe

  1. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  2. HIGH TEMPERATURE DISPLACEMENT SENSOR

    Institute of Scientific and Technical Information of China (English)

    Xu Longxiang; Zhang Jinyu; Schweitzer Gerhard

    2005-01-01

    A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90~350 mV at 550℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2~3 V at 550℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550℃ in a magnetic bearing system for more than 100 h.

  3. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  4. High-temperature protective coatings on superalloys

    Institute of Scientific and Technical Information of China (English)

    刘培生; 梁开明; 周宏余

    2002-01-01

    Protective coatings are essential for superalloys to serve as blades of gas turb ines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high-temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high-temperature oxidation law of aluminide coatings.

  5. Applications of high-temperature superconductors in power technology[8470 High-current and high-voltage technology: power systems; power transmission lines and cables;

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2003-11-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications.

  6. Computational Modeling of Vortex Generators for Turbomachinery

    Science.gov (United States)

    Chima, R. V.

    2002-01-01

    In this work computational models were developed and used to investigate applications of vortex generators (VGs) to turbomachinery. The work was aimed at increasing the efficiency of compressor components designed for the NASA Ultra Efficient Engine Technology (UEET) program. Initial calculations were used to investigate the physical behavior of VGs. A parametric study of the effects of VG height was done using 3-D calculations of isolated VGs. A body force model was developed to simulate the effects of VGs without requiring complicated grids. The model was calibrated using 2-D calculations of the VG vanes and was validated using the 3-D results. Then three applications of VGs to a compressor rotor and stator were investigated: 1) The results of the 3-D calculations were used to simulate the use of small casing VGs used to generate rotor preswirl or counterswirl. Computed performance maps were used to evaluate the effects of VGs. 2) The body force model was used to simulate large part-span splitters on the casing ahead of the stator. Computed loss buckets showed the effects of the VGs. 3) The body force model was also used to investigate the use of tiny VGs on the stator suction surface for controlling secondary flows. Near-surface particle traces and exit loss profiles were used to evaluate the effects of the VGs.

  7. Unsteady measurement techniques for turbomachinery flows

    Science.gov (United States)

    Jaffa, Nicholas Andrew

    Accurate unsteady measurements are required for studying the flows in high speed turbomachines, which rely on the interaction between rotating and stationary components. Using statistics of phase locked ensembles simplifies the problem, but accurate frequency response in the 10-100 kHz range significantly limits the applicable techniques. This research advances the state of the art for phase resolved measurement techniques using for high speed turbomachinery flows focusing on the following areas: development, validation, and uncertainty quantification. Four methods were developed and implemented: an unsteady total pressure probe, the multiple overheat hot-wire method, the slanted hot-wire method, and the phase peak yaw hot-wire method. These methods allow for the entire phase locked average flow field to be measured (temperature, pressure, and velocity components, swirl angle, etc.). No trusted reference measurement or representative canonical flow exists for comparison of the phase resolved quantities, making validation challenging. Five different validation exercises were performed to increase the confidence and explore the range of applicability. These exercises relied on checking for consistency with expected flow features, comparing independent measurements, and cross validation with CFD. The combined uncertainties for the measurements were quantified using uncertainty estimates from investigations into the elemental error sources. The frequency response uncertainty of constant temperature hot-wire system was investigated using a novel method of illuminating the wire with a laser pulse. The uncertainty analysis provided estimates for the uncertainty in the measurements as well as showing the sensitivity to various sources of error.

  8. Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

    Institute of Scientific and Technical Information of China (English)

    Dipak Kumar; KN Pandey; Dipak Kumar Das

    2016-01-01

    In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying (APS) techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to investigate the phases and microstructure of the as-sprayed, APS-deposited CoNiCrAlY bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of theγ/γ′-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in CoNiCrAlY bond-coatings with excellent thermal cy-clic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

  9. Microstructure studies of air-plasma-spray-deposited CoNiCrAlY coatings before and after thermal cyclic loading for high-temperature application

    Science.gov (United States)

    Kumar, Dipak; Pandey, K. N.; Das, Dipak Kumar

    2016-08-01

    In the present study, bond-coats for thermal barrier coatings were deposited via air plasma spraying (APS) techniques onto Inconel 800 and Hastelloy C-276 alloy substrates. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and atomic force microscopy (AFM) were used to investigate the phases and microstructure of the as-sprayed, APS-deposited CoNiCrAlY bond-coatings. The aim of this work was to study the suitability of the bond-coat materials for high temperature applications. Confirmation of nanoscale grains of the γ/γ'-phase was obtained by TEM, high-resolution TEM, and AFM. We concluded that these changes result from the plastic deformation of the bond-coat during the deposition, resulting in CoNiCrAlY bond-coatings with excellent thermal cyclic resistance suitable for use in high-temperature applications. Cyclic oxidative stability was observed to also depend on the underlying metallic alloy substrate.

  10. A wide bandgap silicon carbide (SiC) gate driver for high-temperature and high-voltage applications

    Energy Technology Data Exchange (ETDEWEB)

    Lamichhane, Ranjan [University of Arkansas; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; BRITTONJr., CHARLES L. [Oak Ridge National Laboratory (ORNL); Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Matt [APEI, Inc.; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas; Podar, Mircea [ORNL; Perez, M [University of Arkansas; Mcnutt, Tyler [APEI, Inc.; Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.

    2014-01-01

    Limitations of silicon (Si) based power electronic devices can be overcome with Silicon Carbide (SiC) because of its remarkable material properties. SiC is a wide bandgap semiconductor material with larger bandgap, lower leakage currents, higher breakdown electric field, and higher thermal conductivity, which promotes higher switching frequencies for high power applications, higher temperature operation, and results in higher power density devices relative to Si [1]. The proposed work is focused on design of a SiC gate driver to drive a SiC power MOSFET, on a Cree SiC process, with rise/fall times (less than 100 ns) suitable for 500 kHz to 1 MHz switching frequency applications. A process optimized gate driver topology design which is significantly different from generic Si circuit design is proposed. The ultimate goal of the project is to integrate this gate driver into a Toyota Prius plug-in hybrid electric vehicle (PHEV) charger module. The application of this high frequency charger will result in lighter, smaller, cheaper, and a more efficient power electronics system.

  11. Forming a Turbomachinery Seals Working Group: An Overview and Discussion

    Science.gov (United States)

    Proctor, Margaret P.

    2007-01-01

    Purose: Identify technical challenges to improving turbomachinery seal leakage and wear performance, reliability and cost effectiveness. Develop a coordinated effort to resolve foundational issues for turbomachinery seal technologies. Identify and foster opportunities for collaboration. Advocate for funding.

  12. Desulfurization at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Panula-Nikkilae, E.; Kurkela, E.; Mojtahedi, W.

    1987-01-01

    Two high-temperature desulfurization methods, furnace injection and gasification-desulfurization are presented. In furnace injection, the efficiency of desulfurization is 50-60%, but this method is applied in energy production plants, where flue gas desulfurization cannot be used. Ca-based sorbents are used as desulfurization material. Factors affecting desulfurization and the effect of injection on the boiler and ash handling are discussed. In energy production based on gasification, very low sulfur emissions can be achieved by conventional low-temperature cleanup. However, high-temperature gas cleaning leads to higher efficiency and can be applied to smaller size classes. Ca-, Fe-, or Zn-based sorbents or mixed metals can be used for desulfurization. Most of the methods under development are based on the use of regenerative sorbents in a cleanup reactor located outside the gasifier. So far, only calcium compounds have been used for desulfurization inside the gasifier.

  13. High Temperature ESP Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Jack Booker; Brindesh Dhruva

    2011-06-20

    The objective of the High Temperature ESP Monitoring project was to develop a downhole monitoring system to be used in wells with bottom hole well temperatures up to 300°C for measuring motor temperature, formation pressure, and formation temperature. These measurements are used to monitor the health of the ESP motor, to track the downhole operating conditions, and to optimize the pump operation. A 220 ºC based High Temperature ESP Monitoring system was commercially released for sale with Schlumberger ESP motors April of 2011 and a 250 ºC system with will be commercially released at the end of Q2 2011. The measurement system is now fully qualified, except for the sensor, at 300 °C.

  14. Strangeness at high temperatures

    CERN Document Server

    Schmidt, Christian

    2013-01-01

    We use up to fourth order cumulants of net strangeness fluctuations and their correlations with net baryon number fluctuations to extract information on the strange meson and baryon contribution to the low temperature hadron resonance gas, the dissolution of strange hadronic states in the crossover region of the QCD transition and the quasi-particle nature of strange quark contributions to the high temperature quark-gluon plasma phase.

  15. Periodic nanostructures imprinted on high-temperature stable sol–gel films by ultraviolet-based nanoimprint lithography for photovoltaic and photonic applications

    Energy Technology Data Exchange (ETDEWEB)

    Back, Franziska [Schott AG, Research and Technology Development, Hattenbergstraße 10, 55122 Mainz (Germany); Fraunhofer-Institut für Silicatforschung ISC, Neunerplatz 2, 97082 Würzburg (Germany); Bockmeyer, Matthias; Rudigier-Voigt, Eveline [Schott AG, Research and Technology Development, Hattenbergstraße 10, 55122 Mainz (Germany); Löbmann, Peer [Fraunhofer-Institut für Silicatforschung ISC, Neunerplatz 2, 97082 Würzburg (Germany)

    2014-07-01

    Nanostructured sol–gel films with high-temperature stability are used in the area of electronics, photonics or biomimetic materials as light-trapping architectures in solar cells, displays, waveguides or as superhydrophobic surfaces with a lotus effect. In this work, high-temperature stable 2-μm nanostructured surfaces were prepared by ultraviolet-based nanoimprint lithography using an alkoxysilane binder incorporating modified silica nanoparticles. Material densification during thermal curing and microstructural evolution which are destined for a high structural fidelity of nanostructured films were investigated in relation to precursor chemistry, particle morphology and particle content of the imprint resist. The mechanism for densification and shrinkage of the films was clarified and correlated with the structural fidelity to explain the influence of the geometrical design on the optical properties. A high internal coherence of the microstructure of the nanostructured films results in a critical film thickness of > 5 μm. The structured glassy layers with high inorganic content show thermal stability up to 800 °C and have a high structural fidelity > 90% with an axial shrinkage of 16% and a horizontal shrinkage of 1%. This material allows the realization of highly effective light-trapping architectures for polycrystalline silicon thin-film solar cells on glass but also for the preparation of 2D photonic crystals for telecommunication wavelengths. - Highlights: • Fundamental research • Hybrid sol–gel material with high-temperature stability and contour accuracy • Ensuring of cost-efficient and industrially feasible processing • Application in photonic and photovoltaic.

  16. Development and Application of Interatomic Potentials for Ultra High Temperature Ceramics (UHTC): ZrB2 and HfB2

    Science.gov (United States)

    Lawson, John W.; Daw, Murray; Bauschlicher

    2012-01-01

    Ultra high temperature ceramics (UHTC) including ZrB2 and HfB2 are characterized by high melting point, good strength, and reasonable oxidation resistance. These materials are of interest for use as sharp leading edges for hypersonic vehicles among other applications. Progress in computational modeling of UHTCs has been limited in part due to the absence of suitable interatomic potentials. We present a Tersoff style parameterization of such potentials for ZrB2 and HfB2 appropriate for atomistic simulations. Parameters are fit to data generated from ab initio calculations. The accuracy of the potentials is assessed against further ab initio data. As a first non ]trivial application, molecular dynamics simulations are performed to evaluate the thermal conductivity of single crystals and the thermal resistance of high symmetry grain boundaries.

  17. High Temperature Capacitor Development

    Energy Technology Data Exchange (ETDEWEB)

    John Kosek

    2009-06-30

    The absence of high-temperature electronics is an obstacle to the development of untapped energy resources (deep oil, gas and geothermal). US natural gas consumption is projected to grow from 22 trillion cubic feet per year (tcf) in 1999 to 34 tcf in 2020. Cumulatively this is 607 tcf of consumption by 2020, while recoverable reserves using current technology are 177 tcf. A significant portion of this shortfall may be met by tapping deep gas reservoirs. Tapping these reservoirs represents a significant technical challenge. At these depths, temperatures and pressures are very high and may require penetrating very hard rock. Logistics of supporting 6.1 km (20,000 ft) drill strings and the drilling processes are complex and expensive. At these depths up to 50% of the total drilling cost may be in the last 10% of the well depth. Thus, as wells go deeper it is increasingly important that drillers are able to monitor conditions down-hole such as temperature, pressure, heading, etc. Commercial off-the-shelf electronics are not specified to meet these operating conditions. This is due to problems associated with all aspects of the electronics including the resistors and capacitors. With respect to capacitors, increasing temperature often significantly changes capacitance because of the strong temperature dependence of the dielectric constant. Higher temperatures also affect the equivalent series resistance (ESR). High-temperature capacitors usually have low capacitance values because of these dielectric effects and because packages are kept small to prevent mechanical breakage caused by thermal stresses. Electrolytic capacitors do not operate at temperatures above 150oC due to dielectric breakdown. The development of high-temperature capacitors to be used in a high-pressure high-temperature (HPHT) drilling environment was investigated. These capacitors were based on a previously developed high-voltage hybridized capacitor developed at Giner, Inc. in conjunction with a

  18. The NDT methods under high temperature service environment

    Directory of Open Access Journals (Sweden)

    Zhang Zhen-guo

    2016-01-01

    Full Text Available Concerning the detective requirement of the equipment under high temperature running status, this paper summarizes the technical characteristics and related applications of several non-destructive testing methods(NDT, such as thermal infrared imaging technology in high temperature, ultrasonic testing technique in high temperature, pulsed eddy current technology in high temperature and magnetic powder flaw detection technology in high temperature, penetration testing technique in high temperature and indirect visual detection in high temperature and on-line monitoring system in high temperature.

  19. Analytical electron microscopy study of new class material Cr2AlC for coating applications at high temperature environments

    Science.gov (United States)

    Iskandar, R.

    2017-04-01

    The interactions between electron and specimens produce wide range of secondary signals from the specimen that can be used in analytical electron microscopy. These signals will give us chemical information and electronic structure information of specimen atoms. Two techniques which based on these secondary signals, X-rays energy-dispersive spectroscopy (XEDS) and electron energy-loss spectroscopy (EELS), are very powerful to be used for characterization materials. These two techniques are complementary each on the other. The former is very useful to quantify heavy elements and the other is very suitable to identify light elements as oxygen and carbon. In this report, we demonstrated the capability of these techniques to investigate microstructure evolution during the oxidation process of thin film Cr2AlC at 1320 °C. This thin film belongs to MAX phase, a new class material, and becomes a promising candidate for coating applications since it exhibits a good oxidation resistant.

  20. Introduction of CORC® wires: highly flexible, round high-temperature superconducting wires for magnet and power transmission applications

    Science.gov (United States)

    Weiss, Jeremy D.; Mulder, Tim; ten Kate, Herman J.; van der Laan, Danko C.

    2017-01-01

    Conductor on Round Core (CORC®) technology has achieved a long sought-after benchmark by enabling the production of round, multifilament, (RE)Ba2Ca3O7-x coated conductors with practical current densities for use in magnets and power applications. Recent progress, including the demonstration of engineering current density beyond 300 Amm-2 at 4.2 K and 20 T, indicates that CORC® cables are a viable conductor for next generation high field magnets. Tapes with 30 μm substrate thickness and tape widths down to 2 mm have improved the capabilities of CORC® technology by allowing the production of CORC® wires as thin as 3 mm in diameter with the potential to enhance the engineering current density further. An important benefit of the thin CORC® wires is their improved flexibility compared to thicker (7-8 mm diameter) CORC® cables. Critical current measurements were carried out on tapes extracted from CORC® wires made using 2 and 3 mm wide tape after bending the wires to various diameters from 10 to 3.5 cm. These thin wires are highly flexible and retain close to 90% of their original critical current even after bending to a diameter of 3.5 cm. A small 5-turn solenoid was constructed and measured as a function of applied magnetic field, exhibiting an engineering current density of 233 Amm-2 at 4.2 K and 10 T. CORC® wires thus form an attractive solution for applications between 4.2 and 77 K, including high-field magnets that require high current densities with small bending diameters, benefiting from a ready-to-use form (similar to NbTi and contrary to Nb3Sn wires) that does not require additional processing following coil construction.

  1. Turbomachinery computational fluid dynamics: asymptotes and paradigm shifts.

    Science.gov (United States)

    Dawes, W N

    2007-10-15

    This paper reviews the development of computational fluid dynamics (CFD) specifically for turbomachinery simulations and with a particular focus on application to problems with complex geometry. The review is structured by considering this development as a series of paradigm shifts, followed by asymptotes. The original S1-S2 blade-blade-throughflow model is briefly described, followed by the development of two-dimensional then three-dimensional blade-blade analysis. This in turn evolved from inviscid to viscous analysis and then from steady to unsteady flow simulations. This development trajectory led over a surprisingly small number of years to an accepted approach-a 'CFD orthodoxy'. A very important current area of intense interest and activity in turbomachinery simulation is in accounting for real geometry effects, not just in the secondary air and turbine cooling systems but also associated with the primary path. The requirements here are threefold: capturing and representing these geometries in a computer model; making rapid design changes to these complex geometries; and managing the very large associated computational models on PC clusters. Accordingly, the challenges in the application of the current CFD orthodoxy to complex geometries are described in some detail. The main aim of this paper is to argue that the current CFD orthodoxy is on a new asymptote and is not in fact suited for application to complex geometries and that a paradigm shift must be sought. In particular, the new paradigm must be geometry centric and inherently parallel without serial bottlenecks. The main contribution of this paper is to describe such a potential paradigm shift, inspired by the animation industry, based on a fundamental shift in perspective from explicit to implicit geometry and then illustrate this with a number of applications to turbomachinery.

  2. High-temperature piezoelectric single crystal ReCa(4)O(BO(3))(3) for sensor applications.

    Science.gov (United States)

    Zhang, Shujun; Fei, Yiting; Frantz, Eric; Snyder, David W; Chai, Bruce H T; Shrout, Thomas R

    2008-12-01

    Large-size and high-quality ReCa(4)O(BO(3))(3) (ReCOB, Re = rare earth) single crystals were grown by the Czochralski pulling method. In this work, the electrical properties were investigated at room temperature and elevated temperature for YCa(4)O(BO(3))(3) (YCOB). The dielectric permittivity, piezoelectric strain coefficient, and electromechanical coupling were found to be on the order of 11, 6.5 pC/N, and 12.5%, respectively, with a high piezoelectric voltage coefficient around 0.067 Vm/N. The electrical resistivity of YCOB was found to be 2 x 10(8) Ohm.m at 800 degrees C, with Q values of 4,500 at 950 degrees C. The frequency/temperature coefficient of YCOB was found to be -75 to -85ppm/K in the temperature range of 30 to 950 degrees C, depending on the crystal orientations. Together with their temperature-independent properties, ReCOB crystals are promising candidates for sensing applications at elevated temperatures.

  3. Contribution to the development of a Doppler global velocimeter for applications in turbomachinery; Contribution au developpement d'un velocimetre global a effet doppler en vue de l'application aux turbomachines

    Energy Technology Data Exchange (ETDEWEB)

    Buchet, H.

    2002-03-15

    Research in turbomachinery requires to develop CFD code as well as experimental device. Measurements are of prime important to set testing bench and access unsteady 3D velocimetry field in rotating parts. Since 1996, DGV technique (Doppler Global Velocimetry) has been developed at ONERA-Toulouse. This technique measure frequency shift caused by Doppler effect. To be applied in turbomachinery, this new method must be compared with PIV. As a reference case, a flow which geometry is comparable to that of a compressor blade grid has been chosen. Tests have been performed at Laboratoire Aerodynamique de Supaero in a transonic wind tunnel on an isolated profile. Wake has been characterised with the two different methods by measuring velocity average flow field. Results are promising and justify further development of the system.(author)

  4. Convergence of Fourier-based time methods for turbomachinery wake passing problems

    Science.gov (United States)

    Gomar, Adrien; Bouvy, Quentin; Sicot, Frédéric; Dufour, Guillaume; Cinnella, Paola; François, Benjamin

    2014-12-01

    The convergence of Fourier-based time methods applied to turbomachinery flows is assessed. The focus is on the harmonic balance method, which is a time-domain Fourier-based approach standing as an efficient alternative to classical time marching schemes for periodic flows. In the literature, no consensus exists concerning the number of harmonics needed to achieve convergence for turbomachinery stage configurations. In this paper it is shown that the convergence of Fourier-based methods is closely related to the impulsive nature of the flow solution, which in turbomachines is essentially governed by the characteristics of the passing wakes between adjacent rows. As a result of the proposed analysis, a priori estimates are provided for the minimum number of harmonics required to accurately compute a given turbomachinery configuration. Their application to several contra-rotating open-rotor configurations is assessed, demonstrating the practical interest of the proposed methodology.

  5. Improved modeling techniques for turbomachinery flow fields

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarayana, B.; Fagan, J.R. Jr.

    1995-12-31

    This program has the objective of developing an improved methodology for modeling turbomachinery flow fields, including the prediction of losses and efficiency. Specifically, the program addresses the treatment of the mixing stress tensor terms attributed to deterministic flow field mechanisms required in steady-state Computational Fluid Dynamic (CFD) models for turbomachinery flow fields. These mixing stress tensors arise due to spatial and temporal fluctuations (in an absolute frame of reference) caused by rotor-stator interaction due to various blade rows and by blade-to-blade variation of flow properties. This will be accomplished in a cooperative program by Penn State University and the Allison Engine Company. These tasks include the acquisition of previously unavailable experimental data in a high-speed turbomachinery environment, the use of advanced techniques to analyze the data, and the development of a methodology to treat the deterministic component of the mixing stress tenor.

  6. High Temperature Piezoelectric Drill

    Science.gov (United States)

    Bao, Xiaoqi; Scott, James; Boudreau, Kate; Bar-Cohen, Yoseph; Sherrit, Stewart; Badescu, Mircea; Shrout, Tom; Zhang, Shujun

    2009-01-01

    The current NASA Decadal mission planning effort has identified Venus as a significant scientific target for a surface in-situ sampling/analyzing mission. The Venus environment represents several extremes including high temperature (460 deg C), high pressure (9 MPa), and potentially corrosive (condensed sulfuric acid droplets that adhere to surfaces during entry) environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than 1000 deg C and the piezoelectric ceramics Bismuth Titanate higher than 600 deg C. A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to 500 deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The drilling performances of a prototype Ultrasonic/Sonic Drill/Corer (USDC) using high temperate piezoelectric ceramics and single crystal were tested at temperature up to 500 deg C. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper.

  7. High temperature superconducting compounds

    Science.gov (United States)

    Goldman, Allen M.

    1992-11-01

    The major accomplishment of this grant has been to develop techniques for the in situ preparation of high-Tc superconducting films involving the use of ozone-assisted molecular beam epitaxy. The techniques are generalizable to the growth of trilayer and multilayer structures. Films of both the DyBa2Cu3O(7-x) and YBa2Cu3O(7-x) compounds as well as the La(2-x)Sr(x)CuO4 compound have been grown on the usual substrates, SrTiO3, YSZ, MgO, and LaAlO3, as well as on Si substrates without any buffer layer. A bolometer has been fabricated on a thermally isolated SiN substrate coated with YSZ, an effort carried out in collaboration with Honeywell Inc. The deposition process facilitates the fabrication of very thin and transparent films creating new opportunities for the study of superconductor-insulator transitions and the investigation of photo-doping with carriers of high temperature superconductors. In addition to a thin film technology, a patterning technology has been developed. Trilayer structures have been developed for FET devices and tunneling junctions. Other work includes the measurement of the magnetic properties of bulk single crystal high temperature superconductors, and in collaboration with Argonne National Laboratory, measurement of electric transport properties of T1-based high-Tc films.

  8. Standard Practice for Installation, Inspection, and Maintenance of Valve-body Pressure-relief Methods for Geothermal and Other High-Temperature Liquid Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This practice covers installation, inspection, and maintenance of valve body cavity pressure relief methods for valves used in geothermal and other high-temperature liquid service. The valve type covered by this practice is a design with an isolated body cavity such that when the valve is in either the open or closed position pressure is trapped in the isolated cavity, and there is no provision to relieve the excess pressure internally. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  9. High-Temperature SiC Power Module with Integrated SiC Gate Drivers for Future High-Density Power Electronics Applications

    Energy Technology Data Exchange (ETDEWEB)

    Whitaker, Mr. Bret [APEI, Inc.; Cole, Mr. Zach [APEI, Inc.; Passmore, Mr. Brandon [APEI, Inc.; Martin, Daniel [APEI, Inc.; Mcnutt, Tyler [APEI, Inc.; Lostetter, Dr. Alex [APEI, Inc.; Ericson, Milton Nance [ORNL; Frank, Steven Shane [ORNL; Britton Jr, Charles L [ORNL; Marlino, Laura D [ORNL; Mantooth, Alan [University of Arkansas; Francis, Dr. Matt [University of Arkansas; Lamichhane, Ranjan [University of Arkansas; Shepherd, Dr. Paul [University of Arkansas; Glover, Dr. Michael [University of Arkansas

    2014-01-01

    This paper presents the testing results of an all-silicon carbide (SiC) intelligent power module (IPM) for use in future high-density power electronics applications. The IPM has high-temperature capability and contains both SiC power devices and SiC gate driver integrated circuits (ICs). The high-temperature capability of the SiC gate driver ICs allows for them to be packaged into the power module and be located physically close to the power devices. This provides a distinct advantage by reducing the gate driver loop inductance, which promotes high frequency operation, while also reducing the overall volume of the system through higher levels of integration. The power module was tested in a bridgeless-boost converter to showcase the performance of the module in a system level application. The converter was initially operated with a switching frequency of 200 kHz with a peak output power of approximately 5 kW. The efficiency of the converter was then evaluated experimentally and optimized by increasing the overdrive voltage on the SiC gate driver ICs. Overall a peak efficiency of 97.7% was measured at 3.0 kW output. The converter s switching frequency was then increased to 500 kHz to prove the high frequency capability of the power module was then pushed to its limits and operated at a switching frequency of 500 kHz. With no further optimization of components, the converter was able to operate under these conditions and showed a peak efficiency of 95.0% at an output power of 2.1 kW.

  10. Panel report on high temperature ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Nolet, T C [ed.

    1979-01-01

    Fundamental research is reported concerning high temperature ceramics for application in turbines, engines, batteries, gasifiers, MHD, fuel cells, heat exchangers, and hot wall combustors. Ceramics microstructure and behavior are included. (FS)

  11. Four-Spot Time-Of-Flight Laser Anemometer For Turbomachinery

    Science.gov (United States)

    Wernet, Mark P.; Skoch, Gary J.

    1995-01-01

    Two-color, four-spot time-of-flight laser anemometer designed for measuring flow velocity within narrow confines of small centrifugal compressor. Apparatus well suited for measuring fast (typical speeds 160 to 700 m/s), highly turbulent gas flows in turbomachinery. Other potential applications include measurement of gas flows in pipelines and in flows from explosions.

  12. Characterization of Ni19.5Ti50.5Pd25Pt5 High-Temperature Shape Memory Alloy Springs and their Potential Application in Aeronautics

    Science.gov (United States)

    Stebner, Aaron; Padula, Santo A.; Noebe, Ronald D.

    2008-01-01

    Shape memory alloys (SMAs) have been used as actuators in many different industries since the discovery of the shape memory effect, but the use of SMAs as actuation devices in aeronautics has been limited due to the temperature constraints of commercially available materials. Consequently, work is being done at NASA's Glenn Research Center to develop new SMAs capable of being used in high temperature environments. One of the more promising high-temperature shape memory alloys (HTSMAs) is Ni19.5Ti50.5Pd25Pt5. Recent work has shown that this material is capable of being used in operating environments of up to 250 C. This material has been shown to have very useful actuation capabilities, demonstrating repeatable strain recoveries up to 2.5% in the presence of an externally applied load. Based on these findings, further work has been initiated to explore potential applications and alternative forms of this alloy, such as springs. Thus, characterization of Ni19.5Ti50.5Pd25Pt5 springs, including their mechanical response and how variations in this response correlate to changes in geometric parameters, are discussed. The effects of loading history, or training, on spring behavior were also investigated. A comparison of the springs with wire actuators is made and the benefits of using one actuator form as opposed to the other discussed. These findings are used to discuss design considerations for a surge-control mechanism that could be used in the centrifugal compressor of a T-700 helicopter engine.

  13. Characterization of Ni19.5Ti50.5Pd25Pt5 High-Temperature Shape Memory Alloy Springs and their Potential Application in Aeronautics

    Science.gov (United States)

    Stebner, Aaron; Padula, Santo A.; Noebe, Ronald D.

    2008-01-01

    Shape memory alloys (SMAs) have been used as actuators in many different industries since the discovery of the shape memory effect, but the use of SMAs as actuation devices in aeronautics has been limited due to the temperature constraints of commercially available materials. Consequently, work is being done at NASA's Glenn Research Center to develop new SMAs capable of being used in high temperature environments. One of the more promising high-temperature shape memory alloys (HTSMAs) is Ni19.5Ti50.5Pd25Pt5. Recent work has shown that this material is capable of being used in operating environments of up to 250 C. This material has been shown to have very useful actuation capabilities, demonstrating repeatable strain recoveries up to 2.5% in the presence of an externally applied load. Based on these findings, further work has been initiated to explore potential applications and alternative forms of this alloy, such as springs. Thus, characterization of Ni19.5Ti50.5Pd25Pt5 springs, including their mechanical response and how variations in this response correlate to changes in geometric parameters, are discussed. The effects of loading history, or training, on spring behavior were also investigated. A comparison of the springs with wire actuators is made and the benefits of using one actuator form as opposed to the other discussed. These findings are used to discuss design considerations for a surge-control mechanism that could be used in the centrifugal compressor of a T-700 helicopter engine.

  14. Silicon carbide, an emerging high temperature semiconductor

    Science.gov (United States)

    Matus, Lawrence G.; Powell, J. Anthony

    1991-01-01

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  15. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  16. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  17. High temperature interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gozar, A., E-mail: adrian.gozar@yale.edu [Yale University, New Haven, CT 06511 (United States); Bozovic, I. [Yale University, New Haven, CT 06511 (United States); Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2016-02-15

    Highlight: • This review article covers the topic of high temperature interface superconductivity. • New materials and techniques used for achieving interface superconductivity are discussed. • We emphasize the role played by the differences in structure and electronic properties at the interface with respect to the bulk of the constituents. - Abstract: High-T{sub c} superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-T{sub c} Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both ‘passive’ hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  18. High temperature catalytic membrane reactors

    Energy Technology Data Exchange (ETDEWEB)

    1990-03-01

    Current state-of-the-art inorganic oxide membranes offer the potential of being modified to yield catalytic properties. The resulting modules may be configured to simultaneously induce catalytic reactions with product concentration and separation in a single processing step. Processes utilizing such catalytically active membrane reactors have the potential for dramatically increasing yield reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity. Examples of commercial interest include hydrogenation, dehydrogenation, partial and selective oxidation, hydrations, hydrocarbon cracking, olefin metathesis, hydroformylation, and olefin polymerization. A large portion of the most significant reactions fall into the category of high temperature, gas phase chemical and petrochemical processes. Microporous oxide membranes are well suited for these applications. A program is proposed to investigate selected model reactions of commercial interest (i.e. dehydrogenation of ethylbenzene to styrene and dehydrogenation of butane to butadiene) using a high temperature catalytic membrane reactor. Membranes will be developed, reaction dynamics characterized, and production processes developed, culminating in laboratory-scale demonstration of technical and economic feasibility. As a result, the anticipated increased yield per reactor pass economic incentives are envisioned. First, a large decrease in the temperature required to obtain high yield should be possible because of the reduced driving force requirement. Significantly higher conversion per pass implies a reduced recycle ratio, as well as reduced reactor size. Both factors result in reduced capital costs, as well as savings in cost of reactants and energy.

  19. Multiscale Modeling of Ultra High Temperature Ceramics (UHTC) ZrB2 and HfB2: Application to Lattice Thermal Conductivity

    Science.gov (United States)

    Lawson, John W.; Daw, Murray S.; Squire, Thomas H.; Bauschlicher, Charles W.

    2012-01-01

    We are developing a multiscale framework in computational modeling for the ultra high temperature ceramics (UHTC) ZrB2 and HfB2. These materials are characterized by high melting point, good strength, and reasonable oxidation resistance. They are candidate materials for a number of applications in extreme environments including sharp leading edges of hypersonic aircraft. In particular, we used a combination of ab initio methods, atomistic simulations and continuum computations to obtain insights into fundamental properties of these materials. Ab initio methods were used to compute basic structural, mechanical and thermal properties. From these results, a database was constructed to fit a Tersoff style interatomic potential suitable for atomistic simulations. These potentials were used to evaluate the lattice thermal conductivity of single crystals and the thermal resistance of simple grain boundaries. Finite element method (FEM) computations using atomistic results as inputs were performed with meshes constructed on SEM images thereby modeling the realistic microstructure. These continuum computations showed the reduction in thermal conductivity due to the grain boundary network.

  20. A novel no-insulation winding technique of high temperature-superconducting racetrack coil for rotating applications: A progress report in Korea university

    Science.gov (United States)

    Choi, Y. H.; Song, J. B.; Yang, D. G.; Kim, Y. G.; Hahn, S.; Lee, H. G.

    2016-10-01

    This paper presents our recent progress on core technology development for a megawatt-class superconducting wind turbine generator supported by the international collaborative R&D program of the Korea Institute of Energy Technology Evaluation and Planning. To outperform the current high-temperature-superconducting (HTS) magnet technology in the wind turbine industry, a novel no-insulation winding technique was first proposed to develop the second-generation HTS racetrack coil for rotating applications. Here, we briefly report our recent studies on no-insulation (NI) winding technique for GdBCO coated conductor racetrack coils in the following areas: (1) Charging-discharging characteristics of no-insulation GdBCO racetrack coils with respect to external pressures applied to straight sections; (2) thermal and electrical stabilities of no-insulation GdBCO racetrack coils encapsulated with various impregnating materials; (3) quench behaviors of no-insulation racetrack coils wound with GdBCO conductor possessing various lamination layers; (4) electromagnetic characteristics of no-insulation GdBCO racetrack coils under time-varying field conditions. Test results confirmed that this novel NI winding technique was highly promising. It could provide development of a compact, mechanically dense, and self-protecting GdBCO magnet for use in real-world superconducting wind turbine generators.

  1. Semi-structured meshes for axial turbomachinery blades

    Science.gov (United States)

    Sbardella, L.; Sayma, A. I.; Imregun, M.

    2000-03-01

    This paper describes the development and application of a novel mesh generator for the flow analysis of turbomachinery blades. The proposed method uses a combination of structured and unstructured meshes, the former in the radial direction and the latter in the axial and tangential directions, in order to exploit the fact that blade-like structures are not strongly three-dimensional since the radial variation is usually small. The proposed semi-structured mesh formulation was found to have a number of advantages over its structured counterparts. There is a significant improvement in the smoothness of the grid spacing and also in capturing particular aspects of the blade passage geometry. It was also found that the leading- and trailing-edge regions could be discretized without generating superfluous points in the far field, and that further refinements of the mesh to capture wake and shock effects were relatively easy to implement. The capability of the method is demonstrated in the case of a transonic fan blade for which the steady state flow is predicted using both structured and semi-structured meshes. A totally unstructured mesh is also generated for the same geometry to illustrate the disadvantages of using such an approach for turbomachinery blades. Copyright

  2. Pebble Bed Reactors Design Optimization Methods and their Application to the Pebble Bed Fluoride Salt Cooled High Temperature Reactor (PB-FHR)

    Science.gov (United States)

    Cisneros, Anselmo Tomas, Jr.

    and PEBBED for a high temperature gas cooled pebble bed reactor. Three parametric studies were performed for exploring the design space of the PB-FHR---to select a fuel design for the PB-FHR] to select a core configuration; and to optimize the PB-FHR design. These parametric studies investigated trends in the dependence of important reactor performance parameters such as burnup, temperature reactivity feedback, radiation damage, etc on the reactor design variables and attempted to understand the underlying reactor physics responsible for these trends. A pebble fuel parametric study determined that pebble fuel should be designed with a carbon to heavy metal ratio (C/HM) less than 400 to maintain negative coolant temperature reactivity coefficients. Seed and thorium blanket-, seed and inert pebble reflector- and seed only core configurations were investigated for annular FHR PBRs---the C/HM of the blanket pebbles and discharge burnup of the thorium blanket pebbles were additional design variable for core configurations with thorium blankets. Either a thorium blanket or graphite pebble reflector is required to shield the outer graphite reflector enough to extend its service lifetime to 60 EFPY. The fuel fabrication costs and long cycle lengths of the thorium blanket fuel limit the potential economic advantages of using a thorium blanket. Therefore, the seed and pebble reflector core configuration was adopted as the baseline core configuration. Multi-objective optimization with respect to economics was performed for the PB-FHR accounting for safety and other physical design constraints derived from the high-level safety regulatory criteria. These physical constraints were applied along in a design tool, Nuclear Application Value Estimator, that evaluated a simplified cash flow economics model based on estimates of reactor performance parameters calculated using correlations based on the results of parametric design studies for a specific PB-FHR design and a set of

  3. Nonlinear plasmonics at high temperatures

    CERN Document Server

    Sivan, Yonatan

    2016-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on {\\em experimentally}-measured data for the metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution, and thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modelling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high temperature non...

  4. Nonlinear plasmonics at high temperatures

    Directory of Open Access Journals (Sweden)

    Sivan Yonatan

    2017-01-01

    Full Text Available We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  5. Nonlinear plasmonics at high temperatures

    Science.gov (United States)

    Sivan, Yonatan; Chu, Shi-Wei

    2017-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  6. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  7. Development of high temperature capable piezoelectric sensors

    Science.gov (United States)

    Suprock, Andrew D.; Tittmann, Bernhard R.

    2017-02-01

    The objective of the project was to investigate the influence of the temperature effect on ultrasonic transducers based on a comparison of the effects of high temperature conditions versus those of high temperature and irradiation on the transducer system. There was also a preliminary move towards the establishment of the means for optimizing the bulk single crystal transducer fabrication process in order to achieve peak efficiency and maximum effectiveness in both irradiated and non-irradiated high temperature applications. Optimization of the material components within the transducer will greatly increase non-destructive testing abilities for industry, structural health monitoring. Here is presented a progress report on the testing of several different piezoelectric materials under high temperature conditions. The viability of aluminum nitride (AlN) as a transducer material in high temperature conditions has been previously explored [1] and has been further tested to ensure reliability. Bistmuth Titanate (BiT) has also been tested and has displayed excellent effectiveness for high temperature application.

  8. Identification of Turbomachinery Noise Sources Using Acoustical Holography Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Evaluation and enhancement of the acoustical performance of turbomachinery requires knowledge of the acoustic sources. However, the noise generation mechanisms...

  9. Small Scale High Speed Turbomachinery

    Science.gov (United States)

    London, Adam P. (Inventor); Droppers, Lloyd J. (Inventor); Lehman, Matthew K. (Inventor); Mehra, Amitav (Inventor)

    2015-01-01

    A small scale, high speed turbomachine is described, as well as a process for manufacturing the turbomachine. The turbomachine is manufactured by diffusion bonding stacked sheets of metal foil, each of which has been pre-formed to correspond to a cross section of the turbomachine structure. The turbomachines include rotating elements as well as static structures. Using this process, turbomachines may be manufactured with rotating elements that have outer diameters of less than four inches in size, and/or blading heights of less than 0.1 inches. The rotating elements of the turbomachines are capable of rotating at speeds in excess of 150 feet per second. In addition, cooling features may be added internally to blading to facilitate cooling in high temperature operations.

  10. Active magnetic bearings for optimum turbomachinery design

    Science.gov (United States)

    Hustak, J.; Kirk, R. G.; Schoeneck, K. A.

    1985-01-01

    The design and shop test results are given for a high speed eight stage centrifugal compressor supported by active magnetic bearings. A brief summary of the rotor dynamics analysis is presented with specific attention given to design considerations for optimum rotor stability. The concerns for retrofit of magnetic bearings in existing machinery are discussed with supporting analysis of a four stage centrifugal compressor. Recommendations are given on design and analysis requirements for successful machinery operation of either retrofit or new design turbomachinery.

  11. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  12. Study and control of the conductivity of Nb-doped Bi4Ti3O12 for high temperature piezoelectric applications

    Directory of Open Access Journals (Sweden)

    Damjanovic, D.

    1999-12-01

    Full Text Available Bismuth-based layered compounds have been considered during the last years as interesting materials for high temperature piezoelectric applications, due to their stability and wide thermal range of the ferroelectric activity. The high electrical conductivity present at high temperatures has been a disadvantage for the potential applications of these compounds. On Bi4Ti3O12 (BIT, different doping, such as Nb5+ and W6+ were used to increase resistivity. It has been shown that Nb5+ doping modifies piezoelectric response, passing from relatively high hysteretic to linear and almost completely non-hysteretic. In the present work, the effect of Nb5+ doping related to the conduction response is investigated. Studies of the I-V curves as a function of the temperature allows us, for the first time, to measure the conductivity of these compounds at room temperature (RT and to discuss which are the microstructural elements that control the conductivity of the material using a serial electrical model. It is shown that at temperatures between RT and 125ºC the grain boundary conductivity limits the total conductivity. At higher temperatures, the material conducts mainly through the bulk of grains. Conduction type, conductivity thermal regimes and chemical composition may explain the change in the piezoelectric behaviour.Compuestos laminares de bismuto han sido considerados en los últimos años materiales interesantes como piezoeléctricos en aplicaciones de alta temperatura, debido a su estabilidad y amplio rango térmico de existencia de actividad ferroeléctrica. Sin embargo, la elevada conductividad presente a altas temperaturas ha sido una desventaja para las potenciales aplicaciones de estos compuestos. En el caso de Bi4Ti3O12 (BIT, diferentes dopantes como Nb5+ o W6+ han sido empleados para aumentar la resistencia eléctrica del material. Es conocido que el dopado con Nb5+ modifica la respuesta piezoeléctrica del material pasando de presentar una

  13. Improved ferroelectric and pyroelectric properties of Pb-doped SrBi{sub 4}Ti{sub 4}O{sub 15} ceramics for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Venkata Ramana, E., E-mail: venkataramanaesk@rediffmail.com [I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro 3810 193 (Portugal); Graça, M.P.F.; Valente, M.A. [I3N-Aveiro, Department of Physics, University of Aveiro, Aveiro 3810 193 (Portugal); Bhima Sankaram, T. [Materials Research Laboratory, Department of Physics, Osmania University, Hyderabad 500 007 (India)

    2014-01-15

    Highlights: • Sr{sub 1−x}Pb{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (SPBT, x = 0 − 0.4) ceramics were synthesized by soft chemical method. • X-ray diffraction analysis confirmed the formation of bismuth layered structure. • SEM images showed plate like grain morphology with random orientation of plate faces. • Pb-doping resulted in improved ferroelectricity of SrBi{sub 4}Ti{sub 4}O{sub 15} ceramics. • Pb-doped SrBi{sub 4}Ti{sub 4}O{sub 15} exhibited improved pyroelectric properties with high T{sub C}. -- Abstract: Ferroelectric properties of Pb-modified strontium bismuth titanate ceramics with chemical formula Sr{sub 1−x}Pb{sub x}Bi{sub 4}Ti{sub 4}O{sub 15} (x = 0–0.4) were investigated. Polycrystalline ceramics were synthesized by soft chemical method to study the effect of Pb-doping on its physical properties. X-ray diffraction analysis revealed a bismuth layered structure for all the compounds. The doping resulted in an increased tetragonal strain and improved ferroelectric properties. Scanning electron microscope images showed plate like grain morphology with random orientation of platelets. The ferroelectric transition temperature of the ceramics increased systematically from 525 °C to 560 °C with the increase of doping concentration. The piezoelectric coefficient (d{sub 33}) of the ceramics was enhanced significantly with Pb doping, exhibiting a maximum value of 21.8 pC/N for 40 mol.% Pb-doped SBT. Pyroelectric studies carried out using the Byer–Roundy method indicated that the modified SBT ceramics are promising candidates for high temperature pyroelectric applications.

  14. Transient heat transfer behavior of water spray evaporative cooling on a stainless steel cylinder with structured surface for safety design application in high temperature scenario

    Science.gov (United States)

    Aamir, Muhammad; Liao, Qiang; Hong, Wang; Xun, Zhu; Song, Sihong; Sajid, Muhammad

    2017-02-01

    High heat transfer performance of spray cooling on structured surface might be an additional measure to increase the safety of an installation against any threat caused by rapid increase in the temperature. The purpose of present experimental study is to explore heat transfer performance of structured surface under different spray conditions and surface temperatures. Two cylindrical stainless steel samples were used, one with pyramid pins structured surface and other with smooth surface. Surface heat flux of 3.60, 3.46, 3.93 and 4.91 MW/m2 are estimated for sample initial average temperature of 600, 700, 800 and 900 °C, respectively for an inlet pressure of 1.0 MPa. A maximum cooling rate of 507 °C/s was estimated for an inlet pressure of 0.7 MPa at 900 °C for structured surface while for smooth surface maximum cooling rate of 356 °C/s was attained at 1.0 MPa for 700 °C. Structured surface performed better to exchange heat during spray cooling at initial sample temperature of 900 °C with a relative increase in surface heat flux by factor of 1.9, 1.56, 1.66 and 1.74 relative to smooth surface, for inlet pressure of 0.4, 0.7, 1.0 and 1.3 MPa, respectively. For smooth surface, a decreasing trend in estimated heat flux is observed, when initial sample temperature was increased from 600 to 900 °C. Temperature-based function specification method was utilized to estimate surface heat flux and surface temperature. Limited published work is available about the application of structured surface spray cooling techniques for safety of stainless steel structures at very high temperature scenario such as nuclear safety vessel and liquid natural gas storage tanks.

  15. Transient heat transfer behavior of water spray evaporative cooling on a stainless steel cylinder with structured surface for safety design application in high temperature scenario

    Science.gov (United States)

    Aamir, Muhammad; Liao, Qiang; Hong, Wang; Xun, Zhu; Song, Sihong; Sajid, Muhammad

    2016-05-01

    High heat transfer performance of spray cooling on structured surface might be an additional measure to increase the safety of an installation against any threat caused by rapid increase in the temperature. The purpose of present experimental study is to explore heat transfer performance of structured surface under different spray conditions and surface temperatures. Two cylindrical stainless steel samples were used, one with pyramid pins structured surface and other with smooth surface. Surface heat flux of 3.60, 3.46, 3.93 and 4.91 MW/m2 are estimated for sample initial average temperature of 600, 700, 800 and 900 °C, respectively for an inlet pressure of 1.0 MPa. A maximum cooling rate of 507 °C/s was estimated for an inlet pressure of 0.7 MPa at 900 °C for structured surface while for smooth surface maximum cooling rate of 356 °C/s was attained at 1.0 MPa for 700 °C. Structured surface performed better to exchange heat during spray cooling at initial sample temperature of 900 °C with a relative increase in surface heat flux by factor of 1.9, 1.56, 1.66 and 1.74 relative to smooth surface, for inlet pressure of 0.4, 0.7, 1.0 and 1.3 MPa, respectively. For smooth surface, a decreasing trend in estimated heat flux is observed, when initial sample temperature was increased from 600 to 900 °C. Temperature-based function specification method was utilized to estimate surface heat flux and surface temperature. Limited published work is available about the application of structured surface spray cooling techniques for safety of stainless steel structures at very high temperature scenario such as nuclear safety vessel and liquid natural gas storage tanks.

  16. Materials, Turbomachinery and Heat Exchangers for Supercritical CO2 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark; Nellis, Greg; Corradini, Michael

    2012-10-19

    The objective of this project is to produce the necessary data to evaluate the performance of the supercritical carbon dioxide cycle. The activities include a study of materials compatibility of various alloys at high temperatures, the heat transfer and pressure drop in compact heat exchanger units, and turbomachinery issues, primarily leakage rates through dynamic seals. This experimental work will serve as a test bed for model development and design calculations, and will help define further tests necessary to develop high-efficiency power conversion cycles for use on a variety of reactor designs, including the sodium fast reactor (SFR) and very high-temperature gas reactor (VHTR). The research will be broken into three separate tasks. The first task deals with the analysis of materials related to the high-temperature S-CO{sub 2} Brayton cycle. The most taxing materials issues with regard to the cycle are associated with the high temperatures in the reactor side heat exchanger and in the high-temperature turbine. The system could experience pressures as high as 20MPa and temperatures as high as 650°C. The second task deals with optimization of the heat exchangers required by the S-CO{sub 2} cycle; the S-CO{sub 2} flow passages in these heat exchangers are required whether the cycle is coupled with a VHTR or an SFR. At least three heat exchangers will be required: the pre-cooler before compression, the recuperator, and the heat exchanger that interfaces with the reactor coolant. Each of these heat exchangers is unique and must be optimized separately. The most challenging heat exchanger is likely the pre-cooler, as there is only about a 40°C temperature change but it operates close to the CO{sub 2} critical point, therefore inducing substantial changes in properties. The proposed research will focus on this most challenging component. The third task examines seal leakage through various dynamic seal designs under the conditions expected in the S-CO{sub 2} cycle

  17. High temperature nanoplasmonics

    Science.gov (United States)

    Alabastri, Alessandro; Toma, Andrea; Malerba, Mario; De Angelis, Francesco; Proietti Zaccaria, Remo

    2016-09-01

    Metallic nanostructures can be utilized as heat nano-sources which can find application in different areas such as photocatalysis, nanochemistry or sensor devices. Here we show how the optical response of plasmonic structures is affected by the increase of temperature. In particular we apply a temperature dependent dielectric function model to different nanoparticles finding that the optical responses are strongly dependent on shape and aspect-ratio. The idea is that when metallic structures interact with an electromagnetic field they heat up due to Joule effect. The corresponding temperature increase modifies the optical response of the particle and thus the heating process. The key finding is that, depending on the structures geometry, absorption efficiency can either increase or decrease with temperature. Since absorption relates to thermal energy dissipation and thus to temperature increase, the mechanism leads to positive or negative loops. Consequently, not only an error would be made by neglecting temperature but it would be not even possible to know, a priori, if the error is towards higher or lower values.

  18. High temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...... of the book describe rationalization and illustration of approaches to high temperature PEM systems. Chapters 6 - 13 are devoted to fabrication, optimization and characterization of phosphoric acid-doped polybenzimidazole membranes, the very first electrolyte system that has demonstrated the concept...... of and motivated extensive research activity in the field. The last 11 chapters summarize the state-of-the-art of technological development of high temperature-PEMFCs based on acid doped PBI membranes including catalysts, electrodes, MEAs, bipolar plates, modelling, stacking, diagnostics and applications....

  19. Hydrogen permeable high-temperature membranes. Development and application in gas separation processes and in hydrogen-producing reactions for process heat utilization. Wasserstoffpermeable Hochtemperaturmembranen. Entwicklung und Einsatz in Gastrennprozessen und in Wasserstoff erzeugenden Reaktionen zur Nutzung von Prozesswaerme

    Energy Technology Data Exchange (ETDEWEB)

    Weirich, W.

    1990-04-03

    The thesis deals with hydrogen-permeable, high-temperature membranes consisting of metal-bare or ceramic-base materials, discussing their fabrication and properties as well as the analyses and experimentes performed for studying the applicability of these membranes in hydrogen production processes or in energy conversion processes for the utilization of process heat from HTGR-type reactors. (orig.)

  20. Calculation of alternating current losses in stacks and coils made of second generation high temperature superconducting tapes for large scale applications

    DEFF Research Database (Denmark)

    Zermeno, Victor M. R.; Abrahamsen, Asger Bech; Mijatovic, Nenad;

    2013-01-01

    A homogenization method to model a stack of second generation High Temperature Superconducting tapes under AC applied transport current or magnetic field has been obtained. The idea is to find an anisotropic bulk equivalent for the stack such that the geometrical layout of the internal alternatin...

  1. Intermetallic-based high-temperature materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-07-01

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminides are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  2. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  3. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  4. 10.3 High-temperature Instrumentation

    Science.gov (United States)

    Piazza, Anthony

    2008-01-01

    This viewgraph presentation describes high temperature instrumentation development from 1960-1970, 1980-1990 and 2000-present. The contents include: 1) Background; 2) Objective; 3) Application and Sensor; 4) Attachment Techniques; 5) Evaluation/Characterization Testing; and 6) Future testing.

  5. Anharmonic phonons and high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Crespi, V.H.; Cohen, M.L. (Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States))

    1993-07-01

    We examine a simple model of anharmonic phonons with application to the superconducting isotope effect. Linear and quadratic electron-phonon coupling are considered for various model potentials. The results of the model calculations are compared with the high-temperature superconductors La[sub 2[minus][ital x

  6. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  7. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS Technologies proposes to develop high temperature electrostrictors from bismuth-based ferroelectrics. These materials will exhibit high strain and low loss in...

  8. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  9. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and dev

  10. Development and application of a high-temperature sampling probe for burning chamber conditions of fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M.; Jormanainen, P.; Roine, J.; Paakkinen, K. [VTT Chemistry, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland)

    1996-12-01

    A sampling probe for the burning chamber conditions of fluidized-bed combustion will be developed in this project. The probe will be suitable for sampling vaporous heavy and alkali metals and other condensing compounds (e.g. chlorides) as well combustion gases and alternatively also flue gas particles at high temperatures. The knowledge gained with the probe will help understanding, developing and modeling combustion processes and will thus aid the manufacturers of the boilers. (author)

  11. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    OpenAIRE

    Myles, Timothy D.; Siwon Kim; Radenka Maric; Mustain, William E.

    2015-01-01

    In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC). The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs) were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs) manufactu...

  12. Development and application of a high-temperature sampling probe for burning chamber conditions in fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M. [VTT Chemical Technology, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland). Environmental Technology

    1997-10-01

    Determination of heavy and alkali metals and other condensing compounds (e.g. chlorides) in combustion chamber conditions is limited by the poor suitability of traditional methods for sampling at high temperatures. IFRF has developed a high-temperature sampling probe for sampling HCN and NH{sub 3}, which has been tested for sampling of NH{sub 3} by Chalmers University of Technology in Sweden. VTT Chemical Technology and Chalmers University of Technology have in their preliminary experiments determined contents of vaporous heavy metals in the combustion chamber of a 12 MW circulating fluidized-bed boiler using this probe. According to the results, the modified probe is suitable for heavy metal determination in combustion chamber. Based on this series of experiments, modification of the probe has been started on the own financing of VTT Chemical Technology and a field measurement was performed in November 1994 to test the present version of the probe. Based on the results of that measurement, the probe has been modified further on as a part of this LIEKKI 2 project. Similar kind of a principle has been applied in the probe which has been developed by VTT Energy during 1994. The probe is built for determination of gas composition of fluidized bed in full-scale boilers. The purpose of this project is to develop and test a sampling probe for fluidized bed combustion. The main advantage of the probe is that condensation losses in sampling due to high temperature gradients can be avoided. Thus, the probe is very suitable for sampling vaporous heavy and alkali metals and other condensing species as well as burning gases and alternatively also solids at high temperatures

  13. Influence of active magnetic bearing sensor location on the calculated critical speeds of turbomachinery

    OpenAIRE

    1989-01-01

    The calculation of critical speeds for turbomachinery with active magnetic bearings (AMBs) is of great interest due to the increasing number of applications of this new technology. The potential for increased turbomachine performance through improved AMB design has created the need for a more accurate method for predicting the system's undamped critical speeds. This thesis documents the development of a method which improves the accuracy of critical speed calculation by properl...

  14. Packaging Technology for SiC High Temperature Electronics

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Spry, David J.; Meredith, Roger D.; Nakley, Leah M.; Beheim, Glenn M.; Hunter, Gary W.

    2017-01-01

    High-temperature environment operable sensors and electronics are required for long-term exploration of Venus and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500 C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors in relevant environments. This talk will discuss a ceramic packaging system developed for high temperature electronics, and related testing results of SiC integrated circuits at 500 C facilitated by this high temperature packaging system, including the most recent progress.

  15. Structural integrity and life extension of high-temperature components

    Institute of Scientific and Technical Information of China (English)

    WANG Chun; SHEN Shi-ming

    2005-01-01

    Four different topics for high-temperature components, namely the development of the assessment codes for the structural integrity of high-temperature components, the application of continuous damage mechanics and probabilistic damage mode on the life assessment of high-temperature components, the life extension for high-tem perature components and a proposed strategy for remanufacturing of high-temperature components were discussed in this paper. These topics should provide some important insights for the design and re-design of high- temperature components.

  16. High-Temperature Capacitor Polymer Films

    Science.gov (United States)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  17. High-power stirling-type pulse tube cooler for power engineering applications of high temperature superconductivity; Hochleistungspulsrohrkuehler vom Stirling-Typ fuer energietechnische Anwendungen der Hochtemperatursupraleitung

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Marc

    2015-12-15

    For the cooling of high temperature superconducting 4 MVA machines (motors or generators), a single-stage Stirling-type pulse-tube cryocooler was built. The cooling power, which the cryocooler was aimed for, is 80 - 100 W at 30 K with an electrical input power of 10 kW (8 kW pV-power). The advantages of this cooler type compared to traditional cooling concepts are an increased reliability and long maintenance intervals. While single-stage Stirling-type pulse-tube cryocoolers for the temperature range of liquid nitrogen (77 K) are already commercially available, there exist currently no commercial systems for the temperature range near 30 K, which is the important range for applications of high-temperature superconductivity. The experimental setup consisted of a 10 kW linear compressor, type 2S297W, from CFIC Inc. which was used as the pressure wave generator. The compressor was operated by a Micromaster 440 frequency inverter from Siemens, which was controlled by a custom-made computer program. The cold head was made in inline configuration, in order to avoid deflection losses. During the first cool-downs tests a temperature inhomogeneity occurred in the regenerator at low temperature and high pV-power, which was attributed to a constant mass flow (circular dc-flow) within the regenerator. This firstly observed dc-flow, generates a net energy flow from the hot end to the cold end of the regenerator, which reduces the cooling capacity considerably and hence the minimum attainable temperature is severely increased. For the design and optimization of the cold-head, a cryocooler model was initially created using the commercial simulation software Sage, which did not include the regenerator inhomogeneity seen in the experiment. For the modeling of the observed streaming inhomogeneity caused by the dc-flow, the regenerator was replaced by two identical parallel regenerators with variable transverse thermal coupling. In the inhomogeneous case (without dc-flow) the

  18. Vibration Control in Turbomachinery Using Active Magnetic Journal Bearings

    Science.gov (United States)

    Knight, Josiah D.

    1996-01-01

    The effective use of active magnetic bearings for vibration control in turbomachinery depends on an understanding of the forces available from a magnetic bearing actuator. The purpose of this project was to characterize the forces as functions shaft position. Both numerical and experimental studies were done to determine the characteristics of the forces exerted on a stationary shaft by a magnetic bearing actuator. The numerical studies were based on finite element computations and included both linear and nonlinear magnetization functions. Measurements of the force versus position of a nonrotating shaft were made using two separate measurement rigs, one based on strain gage measurement of forces, the other based on deflections of a calibrated beam. The general trends of the measured principal forces agree with the predictions of the theory while the magnitudes of forces are somewhat smaller than those predicted. Other aspects of theory are not confirmed by the measurements. The measured forces in the normal direction are larger than those predicted by theory when the rotor has a normal eccentricity. Over the ranges of position examined, the data indicate an approximately linear relationship between the normal eccentricity of the shaft and the ratio of normal to principal force. The constant of proportionality seems to be larger at lower currents, but for all cases examined its value is between 0.14 and 0.17. The nonlinear theory predicts the existence of normal forces, but has not predicted such a large constant of proportionality for the ratio. The type of coupling illustrated by these measurements would not tend to cause whirl, because the coupling coefficients have the same sign, unlike the case of a fluid film bearing, where the normal stiffness coefficients often have opposite signs. They might, however, tend to cause other self-excited behavior. This possibility must be considered when designing magnetic bearings for flexible rotor applications, such as gas

  19. Development of a version of the reactor dynamics code DYN3D applicable for High Temperature Reactors; Entwicklung einer Version des Reaktordynamikcodes DYN3D fuer Hochtemperaturreaktoren. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, Ulrich; Apanasevich, Pavel; Baier, Silvio; Duerigen, Susan; Fridman, Emil; Grahn, Alexander; Kliem, Soeren; Merk, Bruno

    2012-07-15

    Based on the reactor dynamics code DYN3D for the simulation of transient processes in Light Water Reactors, a code version DYN3D-HTR for application to graphitemoderated, gas-cooled block-type high temperature reactors has been developed. This development comprises: - the methodical improvement of the 3D steady-state neutron flux calculation for the hexagonal geometry of the HTR fuel element blocks - the development of methods for the generation of homogenised cross section data taking into account the double heterogeneity of the fuel element block structure - the implementation of a 3D model for heat conduction and heat transport in the graphite matrix. The nodal method for neutron flux calculation based on SP3 transport approximation was extended to hexagonal fuel element geometry, where the hexagons are subdivided into triangles, thus the method had finally to be derived for triangular geometry. In triangular geometry, a subsequent subdivision of the hexagonal elements can be considered, and therefore, the effect of systematic mesh refinement can be studied. The algorithm was verified by comparison with Monte Carlo reference solutions, on the node-wise level, as well as also on the pin-wise level. New procedures were developed for the homogenization of the double-heterogeneous fuel element structures. One the one hand, the so-called Reactivity equivalent Physical Transformation (RPT), the two-step homogenization method based on 2D deterministic lattice calculations, was extended to cells with different temperatures of the materials. On the other hand, the progress in development of Monte Carlo methods for spectral calculations, in particular the development of the code SERPENT, opened a new, fully consistent 3D approach, where all details of the structures on fuel particle, fuel compact and fuel block level can be taken into account within one step. Moreover, a 3D heat conduction and heat transport model was integrated into DYN3D to be able to simulate radial

  20. Damping of High-temperature Shape Memory Alloys

    Science.gov (United States)

    Duffy, Kirsten P.; Padula, Santo A., II; Scheiman, Daniel A.

    2008-01-01

    Researchers at NASA Glenn Research Center have been investigating high temperature shape memory alloys as potential damping materials for turbomachinery rotor blades. Analysis shows that a thin layer of SMA with a loss factor of 0.04 or more would be effective at reducing the resonant response of a titanium alloy beam. Two NiTiHf shape memory alloy compositions were tested to determine their loss factors at frequencies from 0.1 to 100 Hz, at temperatures from room temperature to 300 C, and at alternating strain levels of 34-35x10(exp -6). Elevated damping was demonstrated between the M(sub s) and M(sub f) phase transformation temperatures and between the A(sub s) and A(sub f) temperatures. The highest damping occurred at the lowest frequencies, with a loss factor of 0.2-0.26 at 0.1 Hz. However, the peak damping decreased with increasing frequency, and showed significant temperature hysteresis in heating and cooling. Keywords: High-temperature, shape memory alloy, damping, aircraft engine blades, NiTiHf

  1. Developing large eddy simulation for turbomachinery applications.

    Science.gov (United States)

    Eastwood, Simon J; Tucker, Paul G; Xia, Hao; Klostermeier, Christian

    2009-07-28

    For jets, large eddy resolving simulations are compared for a range of numerical schemes with no subgrid scale (SGS) model and for a range of SGS models with the same scheme. There is little variation in results for the different SGS models, and it is shown that, for schemes which tend towards having dissipative elements, the SGS model can be abandoned, giving what can be termed numerical large eddy simulation (NLES). More complex geometries are investigated, including coaxial and chevron nozzle jets. A near-wall Reynolds-averaged Navier-Stokes (RANS) model is used to cover over streak-like structures that cannot be resolved. Compressor and turbine flows are also successfully computed using a similar NLES-RANS strategy. Upstream of the compressor leading edge, the RANS layer is helpful in preventing premature separation. Capturing the correct flow over the turbine is particularly challenging, but nonetheless the RANS layer is helpful. In relation to the SGS model, for the flows considered, evidence suggests issues such as inflow conditions, problem definition and transition are more influential.

  2. Predicting Flutter and Forced Response in Turbomachinery

    Science.gov (United States)

    VanZante, Dale E.; Adamczyk, John J.; Srivastava, Rakesh; Bakhle, Milind A.; Shabbir, Aamir; Chen, Jen-Ping; Janus, J. Mark; To, Wai-Ming; Barter, John

    2005-01-01

    TURBO-AE is a computer code that enables detailed, high-fidelity modeling of aeroelastic and unsteady aerodynamic characteristics for prediction of flutter, forced response, and blade-row interaction effects in turbomachinery. Flow regimes that can be modeled include subsonic, transonic, and supersonic, with attached and/or separated flow fields. The three-dimensional Reynolds-averaged Navier-Stokes equations are solved numerically to obtain extremely accurate descriptions of unsteady flow fields in multistage turbomachinery configurations. Blade vibration is simulated by use of a dynamic-grid-deformation technique to calculate the energy exchange for determining the aerodynamic damping of vibrations of blades. The aerodynamic damping can be used to assess the stability of a blade row. TURBO-AE also calculates the unsteady blade loading attributable to such external sources of excitation as incoming gusts and blade-row interactions. These blade loadings, along with aerodynamic damping, are used to calculate the forced responses of blades to predict their fatigue lives. Phase-lagged boundary conditions based on the direct-store method are used to calculate nonzero interblade phase-angle oscillations; this practice eliminates the need to model multiple blade passages, and, hence, enables large savings in computational resources.

  3. Calculation of three-dimensional transonic flows in turbomachinery with generalized von Mises corrdinate system

    Institute of Scientific and Technical Information of China (English)

    沈孟育; 刘秋生; 张增产

    1996-01-01

    An efficient numerical method for calculating the three-dimensional transonic flows in turbomachinery is proposed. Instead of the Euler equation, streamsurface-governing equations are deduced in the generalized von Mises coordinate system to reflect the flow feature in turbomachinery. Its main advantage is that it is easier to specify more reasonable initial values, i.e. initial streamsurface position, thus accelerating the convergence rate of the iteration process. Moreover, to use the generalized von Mises coordinates makes the present method capable of incorporating the calculation of the flow field, design and modification of the blade contour into a unified algorithm. A rotated finite difference scheme for the streamsurface-governing equations is constructed, and a new measure is presented to deal with the double-value problem of the velocity and density caused by the application of the stream functions as coordinates in the transonic flow. Three test cases were considered with the present approach

  4. Topology Method for Analyses of 3—D Viscous Flow Structure in Transonic Turbomachinery

    Institute of Scientific and Technical Information of China (English)

    YanhuGuo; BaoguoWang; 等

    1997-01-01

    A topology method is presented in this paper to reveal flow tructure occurring insie turbomachinery,in which near wall flow structure is revealed by using wall limiting streamilines and space flow feature is revealed by using space streamilines and cross-section streamlines,As an example ,a computational three-dimensional viscous flow field inside a transonic turbine cascade is studied.Through the analysis,the form and evolution of vortex system and the whole process of separation occurring within this cascade are revealed.The application of topology method for analyze flow structure inside turbomachinmery is very important for understanding flow features and mechanism of flow loss even for improving the design of turbomachinery and increasing its efficiency.

  5. Effect of high-temperature on the swellable organically-modified silica (SOMS) and its application to gas-phase hydrodechlorination of trichloroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Hyuntae; Celik, Gokhan; Gunduz, Seval; Majumdar, Sreshtha Sinha; Dean, Stacey L.; Edmiston, Paul L.; Ozkan, Umit S.

    2017-07-01

    Pd catalysts supported on swellable organically-modified silica (SOMS) and high-temperature-treated swellable organically-modified silica (H-SOMS) were characterized and tested for gas-phase hydrodechlorination (HDC) of trichloroethylene (TCE) conditions. The high-temperature treatment on SOMS resulted in an increase in surface area and pore diameter as well as significant improvement of Pd dispersion on H-SOMS with smaller Pd particle sizes compared to the Pd/SOMS catalyst. Although the high-temperature treatment led to some alteration of the SOMS polysiloxane network, the hydrophobicity and organic vapor adsorption characteristics of SOMS were preserved. The reduction and oxidation characteristics of Pd on SOMS and HSOMS were investigated in situ using XANES technique. It was found that the Pd sites in the pores of SOMS was accessible to small molecules such as H2, facilitating the reduction of PdOx, whereas oxidation of metallic Pd was limited even at higher temperatures when O2 was used. This effect was only observed over Pd/SOMS catalyst. For Pd/H-SOMS, because the pores were more widely open than Pd/SOMS, both reduction and oxidation of Pd were observed. Finally, the catalytic activity of Pd/H-SOMS for gas-phase HDC of TCE was significantly better than Pd/SOMS. When water was added to the reactant stream (TCE + H2O), both Pd/SOMS and Pd/H-SOMS maintained its catalytic performances due to hydrophobic property of the supports.

  6. Rare earth permanent-magnet alloys’ high temperature phase transformation in situ and dynamic observation and its application in material design

    CERN Document Server

    Pan, Shuming

    2013-01-01

    The process of high temperature phase transition of rare earth permanent-magnet alloys is revealed by photographs taken by high voltage TEM. The relationship between the formation of nanocrystal and magnetic properties is discussed in detail, which effects alloys composition and preparation process. The experiment results verified some presumptions, and were valuable for subsequent scientific research and creating new permanent-magnet alloys. The publication is intended for researchers, engineers and managers in the field of material science, metallurgy, and physics. Prof. Shuming Pan is senior engineer of Beijing General Research Institute of Non-ferrous Metal.

  7. Real-time observation system development for high-temperature liquid/solid interfaces and its application to solid-source solution growth of AlN

    Science.gov (United States)

    Kangawa, Yoshihiro; Kusaba, Akira; Sumiyoshi, Hiroaki; Miyake, Hideto; Boćkowski, Michał; Kakimoto, Koichi

    2015-06-01

    Interfacial phenomena at the liquid/solid interface under high temperatures were observed in real time to understand the growth process of AlN during solid-source solution growth. In this study, we used an AlN/α-Al2O3 template as the substrate; these wide-bandgap materials made the substrate transparent to visible light. Therefore, we observed the morphology of the liquid/solid interface through the template from the bottom. In this investigation, a polycrystal formed because of melt-back etching during the initial stage of growth; nevertheless, we succeeded in obtaining real-time images of interfacial phenomena.

  8. Application of the high temperature series expansions method Green’s function theory to the spinel systems: AxA’1-xB2X4

    Science.gov (United States)

    El Grini, A.; Salmi, S.; Marzouk, A.; Benzakour, N.; Bouslykhane, K.; Hourmatallah, A.

    2017-03-01

    The magnetic properties of Mn-Cu ferrites MnxCu1-xFe2O4, have been studied using the many-body Green’s function theory (GFT) and high temperature series expansion theory (HTSE). The thermal magnetization and the magnetic susceptibility are given for different values of magnetic field and dilution x. The transition temperature TC is calculated as a function of Mn concentration. The obtained results are in good agreement with experimental results. The critical exponents associated with the magnetic susceptibility (γ) and the correlation lengths (ν) have been deduced. The obtained values are comparable to those of 3D Heisenberg model.

  9. An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Yun Tu

    2017-02-01

    Full Text Available Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG fabricated in hydrogen (H2-loaded boron–germanium (B–Ge co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration. The regeneration characteristics of the RFBGs and the strain characteristics of the sensor are evaluated. Numerical simulation of the sensor is conducted using a three-dimensional finite element model. Anomalous decay behavior of two regeneration regimes is observed for the FBGs written in H2-loaded B–Ge co-doped fiber. The strain sensor exhibits good linearity, stability and repeatability when exposed to constant high temperatures of up to 540 °C. A satisfactory agreement is obtained between the experimental and numerical results in strain sensitivity. The results demonstrate that the improved metal-packaged strain sensors based on RFBGs in H2-loaded B–Ge co-doped fiber provide great potential for high-temperature applications by addressing the issues of mechanical integrity and packaging.

  10. An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

    Science.gov (United States)

    Tu, Yun; Ye, Lin; Zhou, Shao-Ping; Tu, Shan-Tung

    2017-01-01

    Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG) fabricated in hydrogen (H2)-loaded boron–germanium (B–Ge) co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration. The regeneration characteristics of the RFBGs and the strain characteristics of the sensor are evaluated. Numerical simulation of the sensor is conducted using a three-dimensional finite element model. Anomalous decay behavior of two regeneration regimes is observed for the FBGs written in H2-loaded B–Ge co-doped fiber. The strain sensor exhibits good linearity, stability and repeatability when exposed to constant high temperatures of up to 540 °C. A satisfactory agreement is obtained between the experimental and numerical results in strain sensitivity. The results demonstrate that the improved metal-packaged strain sensors based on RFBGs in H2-loaded B–Ge co-doped fiber provide great potential for high-temperature applications by addressing the issues of mechanical integrity and packaging. PMID:28241465

  11. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard;

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...

  12. A high capacity manganese-based sorbent for regenerative high temperature desulfurization with direct sulfur production conceptual process application to coal gas cleaning

    Energy Technology Data Exchange (ETDEWEB)

    Bakker, W.J.W.; Kapteijn, F.; Moulijn, J.A. [Delft University of Technology, Delft (Netherlands)

    2003-12-15

    A high capacity, monolith or particle shaped, regenerable sorbent has been developed for the desulfurization of a dry type coal gas. It consists of crystalline MnAl{sub 2}O{sub 4}, a small amount of disperse MnO, and an amorphous Mn-Al-O phase. Elemental sulfur is the only observed regeneration product during regeneration with SO{sub 2}. The sorbent can be used in the temperature range between 673 and 1273 K but the optimum capacity is utilized between 1100 and 1200 K. For regeneration with SO{sub 2} the regeneration temperature should be > 873 K to avoid sulfate formation. The sulfur uptake capacity is high and amounts up to 20 wt.% S and the sorbent performance appears to be stable during at least 110 sulfiding and regeneration cycles at 1123 K. For temperatures above 1100 K thermodynamic calculations are in accordance with the observed (solid) phases after sulfiding and regeneration, indicating the predictive potential for high temperatures. The performance of the surface sites that play an important role during desulfurization can, however, not be predicted. The regenerative removal of H{sub 2}S, COS, HCl and HF can possibly take place simultaneously with the same sorbent. A new conceptual process configuration for high temperature coal gas cleaning and sorbent regeneration is proposed. Compared to other processes, less heat exchange equipment is required and no Claus unit is necessary to convert the regeneration product to sulfur.

  13. The modified relaxation time function: A novel analysis technique for relaxation processes. Application to high-temperature molybdenum internal friction peaks

    Energy Technology Data Exchange (ETDEWEB)

    Matteo, C.L. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Avda. Paseo Colon 850, 1063 Buenos Aires (Argentina); Lambri, O.A. [Instituto de Fisica Rosario, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Laboratorio de Materiales, Escuela de Ing. Electrica, Universidad Nacional de Rosario, Avda. Pellegrini 250, (2000) Rosario (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Zelada-Lambri, G.I. [Instituto de Fisica Rosario, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Laboratorio de Materiales, Escuela de Ing. Electrica, Universidad Nacional de Rosario, Avda. Pellegrini 250, (2000) Rosario (Argentina); Sorichetti, P.A. [Departamento de Fisica, Facultad de Ingenieria, Universidad de Buenos Aires, Avda. Paseo Colon 850, 1063 Buenos Aires (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apdo. 644, 48080 Bilbao, Pais Vasco (Spain)

    2008-07-01

    The modified relaxation time (MRT) function, which is based on a general linear viscoelastic formalism, has several important mathematical properties that greatly simplify the analysis of relaxation processes. In this work, the MRT is applied to the study of the relaxation damping peaks in deformed molybdenum at high temperatures. The dependence of experimental data from these relaxation processes with temperature are adequately described by a Havriliak-Negami (HN) function, and the MRT makes it possible to find a relation between the parameters of the HN function and the activation energy of the process. The analysis reveals that for the relaxation peak appearing at temperatures below 900 K, the physical mechanism is related to a vacancy-diffusion-controlled movement of dislocations. In contrast, when the peak appears at temperatures higher than 900 K, the damping is controlled by a mechanism of diffusion in the low-temperature tail of the peak, and in the high-temperature tail of the peak the creation plus diffusion of vacancies at the dislocation line occurs.

  14. 高温贫氧燃烧技术的研究与应用%Study and Application of High Temperature Air Combustion Technology

    Institute of Scientific and Technical Information of China (English)

    马宪国; 郑国耀; 李道林

    2001-01-01

    高温贫氧燃烧技术是90年代初在西方工业发达国家发展起来的一种新型燃烧技术,其特点是不存 在传统燃烧过程中出现的局部高温高氮区,炉膛传热效率显著提高,NOx的生成受到抑制。另外,还介绍了国 外在高温贫氧燃烧技术的最新实验室研究成果。图11参4%High temperature air combustion (HTAC) is a new burring technology developed in indus trial countries in recent years which can evidently enhance heat transfer in the chamber of a furnace and reduce NOx emission. A great deal of study has been done on the basic research and industrial ap plication of the HTAC technology. This paper gives a brief introduction on experimental studies of high temperature air combustion in developed countries. Figs 11 and refs 4.

  15. Survey of Properties of Key Single and Mixture Halide Salts for Potential Application as High Temperature Heat Transfer Fluids for Concentrated Solar Thermal Power Systems

    Directory of Open Access Journals (Sweden)

    Chao-Jen Li

    2014-04-01

    Full Text Available In order to obtain high energy efficiency in a concentrated solar thermal power plant, more and more high concentration ratio to solar radiation are applied to collect high temperature thermal energy in modern solar power technologies. This incurs the need of a heat transfer fluid being able to work at more and more high temperatures to carry the heat from solar concentrators to a power plant. To develop the third generation heat transfer fluids targeting at a high working temperature at least 800 ℃, a research team from University of Arizona, Georgia Institute of Technology, and Arizona State University proposed to use eutectic halide salts mixtures in order to obtain the desired properties of low melting point, low vapor pressure, great stability at temperatures at least 800 ℃, low corrosion, and favorable thermal and transport properties. In this paper, a survey of the available thermal and transport properties of single and eutectic mixture of several key halide salts is conducted, providing information of great significance to researchers for heat transfer fluid development.

  16. Tailoring a High Temperature Corrosion Resistant FeNiCrAl for Oxy-Combustion Application by Thermal Spray Coating and HIP

    Directory of Open Access Journals (Sweden)

    Jarkko Metsäjoki

    2015-10-01

    Full Text Available Oxy-fuel combustion combined with CCS (carbon capture and storage aims to decrease CO2 emissions in energy production using fossil fuels. Oxygen firing changes power plant boiler conditions compared to conventional firing. Higher material temperatures and harsher and more variable environmental conditions cause new degradation processes that are inadequately understood at the moment. In this study, an Fe-Ni-Cr-Al alloy was developed based on thermodynamic simulations. The chosen composition was manufactured as powder by gas atomization. The powder was sieved into two fractions: The finer was used to produce thermal spray coatings by high velocity oxy-fuel (HVOF and the coarser to manufacture bulk specimens by hot isostatic pressing (HIP. The high temperature corrosion properties of the manufactured FeNiCrAl coating and bulk material were tested in laboratory conditions simulating oxy-combustion. The manufacturing methods and the results of high temperature corrosion performance are presented. The corrosion performance of the coating was on average between the bulk steel references Sanicro 25 and TP347HFG.

  17. Application of indium tin oxide (ITO) thin film as a low emissivity film on Ni-based alloy at high temperature

    Science.gov (United States)

    Sun, Kewei; Zhou, Wancheng; Tang, Xiufeng; Luo, Fa

    2016-09-01

    Indium tin oxide (ITO) films as the low emissivity coatings of Ni-based alloy at high temperature were studies. ITO films were deposited on the polished surface of alloy K424 by direct current magnetron sputtering. These ITO-coated samples were heat-treated in air at 600-900 °C for 150 h to explore the effect of high temperature environment on the emissivity. The samples were analyzed by X-ray diffraction (XRD), SEM and EDS. The results show that the surface of sample is integrity after heat processing at 700 °C and below it. A small amount of fine crack is observed on the surface of sample heated at 800 °C and Ti oxide appears. There are lots of fine cracks on the sample annealed at 900 °C and a large number of various oxides are detected. The average infrared emissivities at 3-5 μm and 8-14 μm wavebands were tested by an infrared emissivity measurement instrument. The results show the emissivity of the sample after annealed at 600 and 700 °C is still kept at a low value as the sample before annealed. The ITO film can be used as a low emissivity coating of super alloy K424 up to 700 °C.

  18. High temperature superconductor current leads

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Hinsdale, IL); Poeppel, Roger B. (Glen Ellyn, IL)

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  19. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  20. Study of Application of Boric Acid in High Temperature Coatings%硼酸应用在耐高温涂层中的研究

    Institute of Scientific and Technical Information of China (English)

    闫实; 刘朝辉; 成声月; 刘强; 阮峥; 邓智平

    2015-01-01

    选取硼酸高温脱水后的混合物作为填料,与高岭土、滑石粉、铝粉等填料制备了以有机硅树脂为基料,可以耐受800℃的耐高温防护涂层并测试了涂层的各项性能。为研究硼酸混合物在涂层高温灼烧过程中的作用机理,对涂层在经200℃固化、500℃高温灼烧和700℃高温灼烧后的表层形貌、元素和涂层物质变化情况进行分析。阐明了涂层中有机硅树脂上的有机基团会在500℃时大量分解。硼酸混合物在高温下,会以熔融态填充有机硅树脂分解挥发产生的空隙,并粘接其他颜填料,但是涂层表面会有硼酸混合物脱水造成的少量凹陷存在。%Using silicone resin as base stock, using dehydrated boric acid mixture,kaolin,talcum powder and aluminum powder as fillers, a high temperature coating which can resist 800 ℃ was prepared. And every performance of the coating was tested. In order to research the action mechanism of boric acid mixture in high temperature calcination process of the coating, changes of the surface morphology and composing elements of the coating during solidifying under 200 ℃ and calcining under 500 ℃ and 700 ℃ were analyzed. The results show that, lots of organic groups on the organosilicon resin can be decomposed at 500 ℃;under high temperature, boric acid mixture in the molten state can fill the voids of the organosilicon resin produced by decomposition of organic groups, but a small amount of pits on surface of the coat will be formed by dehydration of boric acid mixture.

  1. Solar-driven high temperature radiant cooling

    Institute of Scientific and Technical Information of China (English)

    SONG ZhaoPei; WANG RuZhu; ZHAI XiaoQiang

    2009-01-01

    Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller's COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%.According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion.

  2. High-temperature discontinuously reinforced aluminum

    Science.gov (United States)

    Zedalis, M. S.; Bryant, J. D.; Gilman, P. S.; Das, S. K.

    1991-08-01

    High-temperature discontinuously reinforced aluminum (HTDRA) composites have been developed for elevated-temperature applications by incorporating SiC particulate reinforcement into a rapidly solidified, high-temperature Al-Fe-V-Si (alloy 8009) matrix. HTDRA combines the superior elevated-temperature strength, stability and corrosion resistance of the 8009 matrix with the excellent specific stiffness and abrasion resistance of the discontinuous SiC particulate reinforcement. On a specific stiffness basis, HTDRA is competitive with Ti-6-Al-4V and 17-4 PH stainless steel to temperatures approaching 480°C. Potential aerospace applications being considered for HTDRA include aircraft wing skins, missile bodies, and miscellaneous engine, spacecraft and hypersonic vehicle components.

  3. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  4. Interface high-temperature superconductivity

    Science.gov (United States)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  5. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  6. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  7. Properties of high temperature SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Falco, C. M.; Wu, C. T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb/sub 3/Sn is outlined, and comments are made on directions future work should take.

  8. Application of in-situ nano-scanning calorimetry and X-ray diffraction to characterize Ni–Ti–Hf high-temperature shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, Patrick J., E-mail: mccluske@ge.com [GE Global Research, One Research Circle, Niskayuna, NY 12309 (United States); Xiao, Kechao [School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 (United States); Gregoire, John M. [Joint Center for Artificial Photosynthesis, California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Dale, Darren [Cornell High Energy Synchrotron Source, Ithaca, NY 14853 (United States); Vlassak, Joost J. [School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 (United States)

    2015-03-10

    Combinatorial nanocalorimetry and synchrotron X-ray diffraction were combined to study the martensite–austenite (M–A) phase transformation behavior of Ni–Ti–Hf shape memory alloys. A thin-film library of Ni–Ti–Hf samples with a range of compositions was deposited on a parallel nano-scanning calorimeter device using sputter deposition. Crystallization of each amorphous as-deposited sample by local heating at approximately 10{sup 4} K/s produced a nanoscale grain structure of austenite and martensite. Individual samples were then cycled through the M–A transformation, while the transformation enthalpy was measured by nanocalorimetry and the low- and high-temperature phase compositions were determined by X-ray diffraction. The techniques enable correlation of the observed behavior during thermal cycling with the thermodynamic and structural properties of the samples.

  9. Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

    Directory of Open Access Journals (Sweden)

    Timothy D. Myles

    2015-10-01

    Full Text Available In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC. The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs manufactured by Reactive Spray Deposition Technology (RSDT. MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored.

  10. Two-particle response in cluster dynamical mean-field theory: formalism and application to the Raman response of high-temperature superconductors.

    Science.gov (United States)

    Lin, Nan; Gull, Emanuel; Millis, Andrew J

    2012-09-07

    A method is presented for the unbiased numerical computation of two-particle response functions of correlated electron materials via a solution of the dynamical mean-field equations in the presence of a perturbing field. The power of the method is demonstrated via a computation of the Raman B(1g) and B(2g) scattering intensities of the two-dimensional Hubbard model in parameter regimes believed to be relevant to high-temperature superconductivity. The theory reproduces the "two-magnon" peak characteristic of the Raman intensity of insulating parent compounds of high-T(c) copper oxide superconductors, and shows how it evolves to a quasiparticle response, as carriers are added. The method can be applied in any situation where a solution of equilibrium dynamical mean-field equations is feasible.

  11. Positron Annihilation Lifetime Spectroscopy Study of Neutron Irradiated High Temperature Superconductors YBa2Cu3O7-δ for Application in Fusion Facilities

    Science.gov (United States)

    Veterníková, J.; Chudý, M.; Slugeň, V.; Eisterer, M.; Weber, H. W.; Sojak, S.; Petriska, M.; Hinca, R.; Degmová, J.; Sabelová, V.

    2012-02-01

    This study focuses on the crystallographic defects introduced by neutron irradiation and the resulting changes of the superconducting properties in the high temperature superconductor YBa2Cu3O7-δ. This material is considered to be most promising for magnet systems in future fusion reactors. Two different bulk samples, pure non-doped YBa2Cu3O7-δ (YBCO) and multi-seed YBa2Cu3O7-δ doped by platinum (MS2F) were studied prior to and after irradiation in the TRIGA MARK II reactor in Vienna. Neutron irradiation is responsible for a significant enhancement of the critical current densities as well as for a reduction in critical temperature. The accumulation of small open volume defects (treatment.

  12. Development of the novel ferrous-based stainless steel for biomedical applications, part I: high-temperature microstructure, mechanical properties and damping behavior.

    Science.gov (United States)

    Wu, Ching-Zong; Chen, Shih-Chung; Shih, Yung-Hsun; Hung, Jing-Ming; Lin, Chia-Cheng; Lin, Li-Hsiang; Ou, Keng-Liang

    2011-10-01

    This research investigated the high-temperature microstructure, mechanical properties, and damping behavior of Fe-9 Al-30 Mn-1C-5 Co (wt.%) alloy by means of electron microscopy, experimental model analysis, and hardness and tensile testing. Subsequent microstructural transformation occurred when the alloy under consideration was subjected to heat treatment in the temperature range of 1000-1150 °C: γ → (γ+κ). The κ-phase carbides had an ordered L'1(2)-type structure with lattice parameter a = 0.385 nm. The maximum yield strength (σ(y)), hardness, elongation, and damping coefficient of this alloy are 645 MPa, Hv 292, ~54%, and 178.5 × 10(-4), respectively. These features could be useful in further understanding the relationship between the biocompatibility and the wear and corrosion resistance of the alloy, so as to allow the development of a promising biomedical material. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Joining of ultra-high temperature ceramics

    OpenAIRE

    Silvestroni, Laura; Sciti, Diletta; Esposito, Laura; Glaeser, Andreas

    2012-01-01

    In the last decade, ultra-high temperature ceramics raised renewed interest after the first studies in the 60's. Thanks to their high melting point, superior to any group of materials, and to their set of interesting physical and engineering properties, they find application in aerospace industry, propulsion field, as cladding materials in generation IV nuclear reactors and solar absorbers in novel HT CSP systems. Recent efforts were devoted to the achievement of high strength and toughness m...

  14. GRAPHENE PEEK COMPOSITES AS HIGH TEMPERATURE ADHESIVES

    Science.gov (United States)

    2017-09-05

    Price DW, Roberts JA, Scott JB, Wadhawan A, Ye Z, Tour JM. Nanotubes in microwave fields : light emission , intense heat, outgassing, and reconstruction...Arepalli S, Yowell LL, Tour JM. Carbon nanotube composite curing through absorption of microwave radiation. Composites Science and Technology. 2008 Dec...polymer that is suitable for high-temperature applications. Graphene is a two-dimensional form of carbon nanomaterial that has been studied

  15. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  16. Minnowbrook V: 2006 Workshop on Unsteady Flows in Turbomachinery. (Conference Abstracts)

    Science.gov (United States)

    LaGraff, John E. (Editor); Ashpis, David E. (Editor); Oldfield, Martin L. G. (Editor); Gostelow, J. Paul (Editor)

    2006-01-01

    This volume contains materials presented at the Minnowbrook V 2006 Workshop on Unsteady Flows in Turbomachinery, held at the Syracuse University Minnowbrook Conference Center, New York, on August 20-23, 2006. The workshop organizers were John E. LaGraff (Syracuse University), Martin L.G. Oldfield (Oxford University), and J. Paul Gostelow (University of Leicester). The workshop followed the theme, venue, and informal format of four earlier workshops: Minnowbrook I (1993), Minnowbrook II (1997), Minnowbrook III (2000), and Minnowbrook IV (2003). The workshop was focused on physical understanding of unsteady flows in turbomachinery, with the specific goal of contributing to engineering application of improving design codes for turbomachinery. The workshop participants included academic researchers from the United States and abroad and representatives from the gas-turbine industry and U.S. Government laboratories. The physical mechanisms discussed were related to unsteady wakes, active flow control, turbulence, bypass and natural transition, separation bubbles and turbulent spots, modeling of turbulence and transition, heat transfer and cooling, surface roughness, unsteady CFD, and DNS. The workshop summary and the plenary discussion transcripts clearly highlight the need for continued vigorous research in the technologically important area of unsteady flows in turbomachines. This volume contains abstracts and copies of select viewgraphs organized according to the workshop sessions. Full-color viewgraphs and animations are included in the CD-ROM version only (Doc.ID 20070024781).

  17. Thermodynamics of High Temperature Plasmas

    Directory of Open Access Journals (Sweden)

    Ettore Minardi

    2009-03-01

    Full Text Available In this work we discuss how and to what extent the thermodynamic concepts and the thermodynamic formalism can be extended to the description of high temperature states of the plasma not necessarily associated with a Boltzmann distribution and with thermal equilibrium.The discussion is based on the “magnetic or electrostatic entropy concept”, an interpretative and predictive tool based on probability and information, defined in a suitably coarse-grained possibility space of all current density or of all electric charge density distributions under testable constraints, and whose variation properties are proven to be related under certain conditions to the equilibrium and the stability of the system. In the case of magnetic equilibrium the potentiality of the magnetic entropy concept is illustrated by comparing the predictions of the current density and pressure profiles with the observations in different tokamak machines and different tokamak regimes, as well as by showing how the equilibrium and the stability in devices as different as the reversed field pinch or the magnetic well are described by the variation properties of the same entropy functional applied to the different situations. In fact it emerges that the maximum of the entropy can be seen in these different cases as an optimization constraint for the minimum of the magnetic energy. The application of the entropy concept to the electrostatic processes shows in particular that the so-called reactive instabilities (non-dissipative, non-resonant instabilities with a marginal point admit a neighboring state with higher entropy and are therefore of special relevance from the point of view of the physical evolution of the system. In this case the thermodynamic formalism allows the introduction of the concept of “thermodynamic fluctuations” of the macroscopic charge density and provides a method for the calculation of the “thermodynamic” fluctuation levels both on the stable as

  18. Forming a Turbomachinery Seals Working Group - An Overview and Discussion

    Science.gov (United States)

    Proctor, Margaret P.

    2007-01-01

    A proposal to form a Turbomachinery Seals Working Group is discussed. Survey responses regarding the purpose, membership, and meeting frequency are presented as well as the areas of expertise and experience of the respondents. The types of seals used, designed, or sold, current work, and technical challenges of turbomachinery seals, their materials, analysis, geometry, manufacturing, maintenance, testing, and incorporation into engine systems are also presented.

  19. Aerodynamics of advanced axial-flow turbomachinery

    Science.gov (United States)

    Serovy, G. K.; Kavanagh, P.; Kiishi, T. H.

    1980-01-01

    A multi-task research program on aerodynamic problems in advanced axial-flow turbomachine configurations was carried out at Iowa State University. The elements of this program were intended to contribute directly to the improvement of compressor, fan, and turbine design methods. Experimental efforts in intra-passage flow pattern measurements, unsteady blade row interaction, and control of secondary flow are included, along with computational work on inviscid-viscous interaction blade passage flow techniques. This final report summarizes the results of this program and indicates directions which might be taken in following up these results in future work. In a separate task a study was made of existing turbomachinery research programs and facilities in universities located in the United States. Some potentially significant research topics are discussed which might be successfully attacked in the university atmosphere.

  20. Application of techniques of dynamic reliability to the assessment of safety a high-temperature Nuclear reactor; Aplicacion de Tecnicas de Fiabilidad Dinamica a la Evaluacion de Seguridad de un Reactor Nuclear de Alta Temperatura

    Energy Technology Data Exchange (ETDEWEB)

    Flores, A.; Gallego Diaz, E.

    2011-07-01

    The main objective of this work is to describe the application of the methodology of integrated analysis of safety to safety assessment of High Temperature Engineering Test Reactor (HTTR), as a demonstration of its ability to be applied to technologies other than light-water reactors, which was initially conceived. The practical application of the method in the case of the HTTR has required the development of a basic model of the HTTR, called DD-HTTR5+, that it allows to represent in a way joint dynamics of the plant and its characteristics of reliability, as well as existing interactions.

  1. Turbomachinery for small solar power plants

    Energy Technology Data Exchange (ETDEWEB)

    Bammert, K.; Heikal, H.; Mobarak, A.

    1981-01-01

    Conversion of solar energy into mechanical or electrical energy in small solar power plants (10 bis 500 kW) requires new design criteria, especially with regard to turbomachinery. The cycles suitable for solar power production are affected by many variables such as kinds of working fluid, range of power and maximum cycle temperature determined by the type of collector. Also, the size of the plant will influence the selection of the various components of the plant, especially that of the turbomachinery. A study of a suitable thermodynamic cycle and working fluid is done for different ranges of power and temperature. The working fluids considered are steam, toluene, and refrigerant 113 for the Rankine cycle systems and air for gas turbine systems. For Rankine cycles, turbine selection is a problem in the small power range. This is mainly due to the fact, that for high efficiency the enthalpy drop should be as high as possible, and the mass flow rate of the working fluid through the turbine becomes very small. This, in turn, requires high rotational speed, multistaging and partial admission, especially if water is the working fluid. Toluene offers better design criteria for the turbine in the same temperature and power range (50-200 kW). For the very small range (10 kW) refrigerant 113 or similar should be used, otherwise severe design problems with the turbine will occur. In this power range, photovoltaics may also be considered. For high concentration systems with Brayton cycles (800-1000/sup 0/C) only open-cycle gas turbine plants should be used.

  2. Redox dynamics in multicomponent, iron-bearing silicate melts and glasses: Application to the float-glass processing of high-temperature silicate glassmelts

    Science.gov (United States)

    Cook, Glen Bennett

    Processing high-strain-point glasses by the float process is challenged by the relative thermochemical properties of glassmelts and the liquid-metal float medium. As the chemical reaction between the glassmelt and the float metal involves dynamic reduction of the glassmelt, this research has examined the constraints on high-temperature float processing of glassmelts by combining metal-alloy/oxide reaction thermodynamics and Wagnerian kinetic models for redox reactions in silicate melts. The dynamic response of Fe-bearing, p-type (polaronic) semiconducting amorphous silicates to a chemical potential gradient of oxygen has been shown to be rate-limited by the chemical diffusion of network-modifying cations. The persistence of this mechanism to very low Fe concentrations in Fe-doped magnesium aluminosilicate glasses was proven with Rutherford backscattering spectroscopy. Three glasses, with 0.1, 0.5, and 1.25 mol. % FeO were reacted with air at temperatures from 710-845sp°C. For all compositions and temperatures, oxidation was dominated by network modifier diffusion; an activation energy of 475 kJ*molsp{-1} characterized the process. Chemical dynamics in a high-temperature float environment were characterized on liquid-liquid reaction couples between two low-Fe sodium-aluminoborosilicate (NABS) glassmelts (0.01 and 0.08 mol. % FeO) and Au-30Sn and Au-28Ge (atomic basis) alloys. Experiments were performed in the temperature range 1250-1450sp°C for 30 min; wavelength-dispersive and Rutherford backscattering spectroscopies were employed. These exothermic liquid-metal alloys display large negative deviations from ideal solution behavior, with significantly depressed chemical activities. Diffusion of Sn or Ge in the NABS glassmelts (depth and concentration) was limited at all temperatures to levels comparable to conventional soda-lime (NCS) float glass (˜2 min on pure Sn at 1100sp°C). Incorporation of Sn or Ge was reduced significantly in the higher-Fe-content NABS

  3. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  4. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  5. Experimental Validation of Passive Safety System Models: Application to Design and Optimization of Fluoride-Salt-Cooled, High-Temperature Reactors

    Science.gov (United States)

    Zweibaum, Nicolas

    The development of advanced nuclear reactor technology requires understanding of complex, integrated systems that exhibit novel phenomenology under normal and accident conditions. The advent of passive safety systems and enhanced modular construction methods requires the development and use of new frameworks to predict the behavior of advanced nuclear reactors, both from a safety standpoint and from an environmental impact perspective. This dissertation introduces such frameworks for scaling of integral effects tests for natural circulation in fluoride-salt-cooled, high-temperature reactors (FHRs) to validate evaluation models (EMs) for system behavior; subsequent reliability assessment of passive, natural- circulation-driven decay heat removal systems, using these validated models; evaluation of life cycle carbon dioxide emissions as a key environmental impact metric; and recommendations for further work to apply these frameworks in the development and optimization of advanced nuclear reactor designs. In this study, the developed frameworks are applied to the analysis of the Mark 1 pebble-bed FHR (Mk1 PB-FHR) under current investigation at the University of California, Berkeley (UCB). (Abstract shortened by UMI.).

  6. Application of automatic inspection system to nondestructive test of heat transfer tubes of primary pressurized water cooler in the high temperature engineering test reactor. Joint research

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Takeshi; Furusawa, Takayuki [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Miyamoto, Satoshi [Japan Atomic Power Company, Tokyo (Japan)

    2001-07-01

    Heat transfer tubes of a primary pressurized water cooled (PPWC) in the high temperature engineering test reactor (HTTR) form the reactor pressure boundary of the primary coolant, therefore are important from the viewpoint of safety. To establish inspection techniques for the heat transfer tubes of the PPWC, an automatic inspection system was developed. The system employs a bobbin coil probe, a rotating probe for eddy current testing (ECT) and a rotating probe for ultrasonic testing (UT). Nondestructive test of a half of the heat transfer tubes of the PPWC was carried out by the automatic inspection system during reactor shutdown period of the HTTR (about 55% in the maximum reactor power in this paper). The nondestructive test results showed that the maximum signal-to-noise ratio was 1.8 in ECT. Pattern and phase of Lissajous wave, which were obtained for the heat transfer tube of the PPWC, were different from those obtained for the artificially defected tube. In UT echo amplitude of the PPWC tubes inspected was lower than 20% of distance-amplitude calibration curve. Thus, it was confirmed that there was no defect in depth, which was more than the detecting standard of the probes, on the outer surface of the heat transfer tubes of the PPWC inspected. (author)

  7. Challenges and Progress in the Development of High-Temperature Shape Memory Alloys Based on NiTiX Compositions for High-Force Actuator Applications

    Science.gov (United States)

    Padula, Santo, II; Bigelow, Glen; Noebe, Ronald; Gaydosh, Darrell; Garg, Anita

    2006-01-01

    Interest in high-temperature shape memory alloys (HTSMA) has been growing in the aerospace, automotive, process control, and energy industries. However, actual materials development has seriously lagged component design, with current commercial NiTi alloys severely limited in their temperature capability. Additions of Pd, Pt, Au, Hf, and Zr at levels greater than 10 at.% have been shown to increase the transformation temperature of NiTi alloys, but with few exceptions, the shape memory behavior (strain recovery) of these NiTiX systems has been determined only under stress free conditions. Given the limited amount of basic mechanical test data and general lack of information regarding the work attributes of these materials, a program to investigate the mechanical behavior of potential HTSMAs, with transformation temperatures between 100 and 500 C, was initiated. This paper summarizes the results of studies, focusing on both the practical temperature limitations for ternary TiNiPd and TiNiPt systems based on the work output of these alloys and the ability of these alloys to undergo repeated thermal cycling under load without significant permanent deformation or "walking". These issues are ultimately controlled by the detwinning stress of the martensite and resistance to dislocation slip of the individual martensite and austenite phases. Finally, general rules that govern the development of useful, high work output, next-generation HTSMA materials, based on the lessons learned in this work, will be provided

  8. Study on Fracture Behavior of 2D-C/C Composite for Application to Control Rod of Very High Temperature Reactor

    Science.gov (United States)

    Sumita, J.; Fujita, I.; Shibata, T.; Makita, T.; Takagi, T.; Kunimoto, E.; Sawa, K.; Kim, W.; Park, J.

    2011-10-01

    For a control rod element of the Very High Temperature Reactor, a carbon fiber reinforced carbon matrix composite (C/C composite) is one of the major candidate materials for its high strength and thermal stability. In this study, in order to establish the data base of the 2D-C/C composite, the fracture data was obtained by simulating the crack expected to be generated under the VHTR condition and the oxidation effect on the fracture behavior was evaluated. Moreover, the fracture mechanism of the C/C composite was investigated through scanning electron microscope observation. This study showed that the oxidized matrix caused reduction of the fracture toughness and the reduction ratio was dependent on the density of matrix and a number cracks. With increasing the oxidation, the fracture toughness is mainly dependent on the fiber characteristics. Furthermore, the crack grows along the boundary between fiber bundles without breaking the fiber. The cracks which were initiated at the interface between the matrix and the fiber were gathered into the voids in the boundary between fiber bundles, and, then, the cracks grew up in the matrix.

  9. Study on Fracture Behavior of 2D-C/C Composite for Application to Control Rod of Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sumita, J; Fujita, I; Shibata, T; Sawa, K [Research Group for VHTR Fuel and Material, Division of Fuels and Materials Engineering, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 4002 Oarai-machi, Higashiibaraki-gun, Ibaraki-ken, 311-1393 (Japan); Makita, T [Functional Materials Development Team, Research and Development Div., Tokai Carbon Co., Ltd., 394-1 Subashiri, Oyama-cho, Sunto-gun, Shizuoka-ken, 410-1431 (Japan); Takagi, T [Engineering Group, FC Unit, FC Operation, Ibiden Co., LTd., 300 Aoyagi-cho, Ogaki-shi, Gifu-ken, 503-8503 (Japan); Kunimoto, E [Atomic Energy Section, Production Division, Toyo Tanso Co., Ltd., 2791 Matsuzaki, Takuma-cho, Mitoyo-shi, Kagawa-ken, 769-1102 (Japan); Kim, W; Park, J, E-mail: sumita.junya@jaea.go.jp [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 1045, Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

    2011-10-29

    For a control rod element of the Very High Temperature Reactor, a carbon fiber reinforced carbon matrix composite (C/C composite) is one of the major candidate materials for its high strength and thermal stability. In this study, in order to establish the data base of the 2D-C/C composite, the fracture data was obtained by simulating the crack expected to be generated under the VHTR condition and the oxidation effect on the fracture behavior was evaluated. Moreover, the fracture mechanism of the C/C composite was investigated through scanning electron microscope observation. This study showed that the oxidized matrix caused reduction of the fracture toughness and the reduction ratio was dependent on the density of matrix and a number cracks. With increasing the oxidation, the fracture toughness is mainly dependent on the fiber characteristics. Furthermore, the crack grows along the boundary between fiber bundles without breaking the fiber. The cracks which were initiated at the interface between the matrix and the fiber were gathered into the voids in the boundary between fiber bundles, and, then, the cracks grew up in the matrix.

  10. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  11. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  12. High temperature alloys: their exploitable potential

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B.; Merz, M.; Nihoul, J.; Ward, J. (eds.) (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center; NET-TEAM, Garching (DE))

    1987-01-01

    This book is the proceedings of a conference dealing with fundamental and technical aspects of the applications of high temperature alloys. It is split into five sections which cover the opening session of the conference and four further sessions covering: the theoretical and practical limits for HT alloys; the potential for development in alloys and processing; engineering considerations; the future outlook. The different sessions each included a number of invited papers followed by a series of posters and were concluded by a presentation of a 'synthesis' by a session rapporteur and general discussion. This structure is retained in the proceedings, including the discussion points in those cases where the authors have provided written answers to the questions raised. This book will be of interest to metallurgists, materials scientists, physicists and research workers in high temperature materials.

  13. Silicon Carbide Nanotube Oxidation at High Temperatures

    Science.gov (United States)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

    Silicon Carbide Nanotubes (SiCNTs) have high mechanical strength and also have many potential functional applications. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The high · temperature oxidation behavior of the nanotubes was of particular interest. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature. Thermogravimetric analysis (TGA) was used to study the oxidation kinetics of SiCNTs at temperatures ranging from 800degC to1300degC. The specific oxidation mechanisms were also investigated.

  14. Capability Study of Ti, Cr, W, Ta and Pt as Seed Layers for Electrodeposited Platinum Films on γ-Al2O3 for High Temperature and Harsh Environment Applications

    Directory of Open Access Journals (Sweden)

    Marietta Seifert

    2017-01-01

    Full Text Available High temperature surface acoustic wave sensors based on radio frequency identification technology require adequate antennas of high efficiency and thermal stability for the signal transmission. Platinum is well known and frequently used as a material of choice for high temperature and harsh environment applications because of the high melting point and its chemical stability. Therefore, one way to realize high temperature stable antennas is the combination of a Pt metallization on an Al 2 O 3 substrate. As a cost-effective technique, the Pt film is deposited via electrochemical deposition. For this growth procedure, a pre-deposited metallization on the Al 2 O 3 layer is required. This paper analyzes the influence of various seed layers (Ta, Ti, W, Cr, Pt on the morphology, stability and electrical properties of the electrochemically-grown Pt thick film after heat treatments up to 1000 ∘ C in air. We find an oxidation of all adhesion layers except for Pt, for which the best electrical properties were measured. Although significant areas of the films delaminate from the substrate, individual anchor structures retain a stable connection between the Pt layer and the rough Al 2 O 3 substrate.

  15. A new evaluation method for micro-fracture plugging in high-temperature deep wells and its application: A case study of the Xushen Gas Field, Songliao Basin

    Directory of Open Access Journals (Sweden)

    Yonggui Liu

    2016-03-01

    Full Text Available Micro-fractures are developed in volcanic layers of Cretaceous Yingcheng Fm in the deep part of Xujiaweizi fault depression, Songliao Basin. In the process of well drilling, various complex problems happen, such as borehole wall slabbing and collapse and serious fluid leakage. Based on conventional drilling fluid plugging evaluation methods, the real situations cannot be presented accurately, especially in fracture feature simulation and plugging effect evaluation. Therefore, a specific micro-fracture plugging evaluation method was put forward especially for high-temperature deep wells in the paper. It is a new type of micro-fracture core model with the fracture apertures in the range of 1–50 μm. It is made of aluminosilicate that is compositionally close to natural rocks. It is good in repeatability with fracture-surface roughness, pore development and fracture-surface morphology close to natural fractures. Obviously, this new model makes up for the deficiencies of the conventional methods. A new micro-fracture plugging evaluation instrument was independently designed with operating temperature of 200 °C and operating pressure of 3.5–5.0 MPa. It can be used to simulate the flow regime of downhole operating fluids, with the advantages of low drilling fluid consumption, convenient operation and low cost. The plugging capacity of the organo-silicone drilling fluid system was evaluated by using this instrument. It is shown that the grain size distribution of the drilling fluid is improved and its anti-collapse capacity is enhanced. Based on the field test in Well XSP-3, the safe drilling problems in volcanic layers with developed micro-fractures are effectively solved by using the drilling fluid formula which is optimized by means of this evaluation method. And the safe drilling is guaranteed in the deep fractured formations in this area.

  16. M5Si3(M=Ti, Nb, Mo) Based Transition-Metal Silicides for High Temperature Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhihong [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Transition metal silicides are being considered for future engine turbine components at temperatures up to 1600 C. Although significant improvement in high temperature strength, room temperature fracture toughness has been realized in the past decade, further improvement in oxidation resistance is needed. Oxidation mechanism of Ti5Si3-based alloys was investigated. Oxidation behavior of Ti5Si3-based alloy strongly depends on the atmosphere. Presence of Nitrogen alters the oxidation behavior of Ti5Si3 by nucleation and growth of nitride subscale. Ti5Si3.2and Ti5Si3C0.5 alloys exhibited an excellent oxidation resistance in nitrogen bearing atmosphere due to limited dissolution of nitrogen and increased Si/Ti activity ratio. MoSi2 coating developed by pack cementation to protect Mo-based Mo-Si-B composites was found to be effective up to 1500 C. Shifting coating composition to T1+T2+Mo3Si region showed the possibility to extend the coating lifetime above 1500 C by more than ten times via formation of slow growing Mo3Si or T2 interlayer without sacrificing the oxidation resistance of the coating. The phase equilibria in the Nb-rich portion of Nb-B system has been evaluated experimentally using metallographic analysis and differential thermal analyzer (DTA). It was shown that Nbss (solid solution) and NbB are the only two primary phases in the 0-40 at.% B composition range, and the eutectic reaction L {leftrightarrow} NbSS + NbB was determined to occur at 2104 ± 5 C by DTA.

  17. Passivation of high temperature superconductors

    Science.gov (United States)

    Vasquez, Richard P. (Inventor)

    1991-01-01

    The surface of high temperature superconductors such as YBa2Cu3O(7-x) are passivated by reacting the native Y, Ba and Cu metal ions with an anion such as sulfate or oxalate to form a surface film that is impervious to water and has a solubility in water of no more than 10(exp -3) M. The passivating treatment is preferably conducted by immersing the surface in dilute aqueous acid solution since more soluble species dissolve into the solution. The treatment does not degrade the superconducting properties of the bulk material.

  18. High Temperature Sorbents for Oxygen

    Science.gov (United States)

    Sharma, Pramod K. (Inventor)

    1996-01-01

    A sorbent capable of removing trace amounts of oxygen (ppt) from a gas stream at a high temperature above 200 C is introduced. The sorbent comprises a porous alumina silicate support such as zeolite containing from 1 to 10 percent by weight of ion exchanged transition metal such as copper or cobalt ions and 0.05 to 1.0 percent by weight of an activator selected from a platinum group metal such as platinum. The activation temperature, oxygen sorption and reducibility are all improved by the presence of the platinum activator.

  19. 第二代高温超导体研究与在聚变领域应用前景%Research and application status in fusion field of second generation high-temperature superconductors

    Institute of Scientific and Technical Information of China (English)

    孙林煜; 李鹏远

    2012-01-01

    简述了高温超导体的特点,系统介绍了第二代高温超导体的研究状况、制备工艺,并分析了第二代高温超导体在核聚变领域的应用前景.%The characteristics of high - temperature superconductors were reviewed. The research issues and the processes of second generation high — temperature superconductors were systematically introduced. In addition, the application of second temperature superconductor in nuclear fusion facility was discussed.

  20. High-temperature polyimide composites and its application in aeronautical engine%航空发动机用PMR聚酰亚胺树脂基复合材料

    Institute of Scientific and Technical Information of China (English)

    谭必恩; 益小苏

    2001-01-01

    This paper reviewed the progress of high-temperature PMR type polyimide matrix composites, and summarized its application in aeronautical engine field.%较全面地综述了PMR聚酰亚胺树脂及其复合材料的制备、性能,并总结了其在航空发动机上的应用情况,分析了目前存在的问题,并提出了将来可能的发展方向。

  1. Fabrication of high performance 2.5D SiO{sub 2f}/Si{sub 3}N{sub 4}-BN composites for high-temperature application

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Y.G.; Zhang, C.R.; Cao, F.; Wang, S.Q.; Hu, H.F.; Qi, G.J. [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha (China)

    2007-01-15

    A radar window for a re-entry vehicle should process critical mechanical properties. Fused silica, BN and Si{sub 3}N{sub 4} ceramics are the three popular materials for such applications, but are limited in some fields for their intrinsic disadvantages. In the present study, 2.5 dimensional silica fiber reinforced Si{sub 3}N{sub 4}-BN matrix composites were prepared by a PIP method through repeated infiltration of hybrid precursor and pyrolysis at high temperature in ammonia atmosphere. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  2. Investigations in the mechanism of carbothermal reduction of yttria stabilized zirconia for ultra-high temperature ceramics application and its influence on yttria contained in it

    Science.gov (United States)

    Sondhi, Anchal

    Zirconium carbide (ZrC) is a high modulus ceramic with an ultra-high melting temperature and, consequently, is capable of withstanding extreme environments. Carbon-carbon composites (CCCs) are important structural materials in current commercial and future hypersonic aircraft; however, these materials may be susceptible to degradation when exposed to elevated temperatures during extreme velocities. At speeds of exceeding Mach 5, intense heating of leading edges of the aircraft triggers rapid oxidation of carbon in CCCs resulting in degradation of the structure and probable failure. Environmental/thermal barrier coatings (EBC/TBC) are employed to protect airfoil structures from extreme conditions. Yttria stabilized zirconia (YSZ) is a well-known EBC/TBC material currently used to protect metallic turbine blades and other aerospace structures. In this work, 3 mol% YSZ has been studied as a potential EBC/TBC on CCCs. However, YSZ is an oxygen conductor and may not sufficiently slow the oxidation of the underlying CCC. Under appropriate conditions, ZrC can form at the interface between CCC and YSZ. Because ZrC is a poor oxygen ion conductor in addition to its stability at high temperatures, it can reduce the oxygen transport to the CCC and thus increase the service lifetime of the structure. This dissertation investigates the thermodynamics and kinetics of the YSZ/ZrC/CCC system and the resulting structural changes across multiple size scales. A series of experiments were conducted to understand the mechanisms and species involved in the carbothermal reduction of ZrO2 to form ZrC. 3 mol% YSZ and graphite powders were uniaxially pressed into pellets and reacted in a graphite (C) furnace. Rietveld x-ray diffraction phase quantification determined that greater fractions of ZrC were formed when carbon was the majority mobile species. These results were validated by modeling the process thermochemically and were confirmed with additional experiments. Measurements were

  3. Current trends in high temperature design

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L. (Illinois Univ., Urbana, IL (United States). Dept. of Mechanical Engineering)

    1992-01-01

    A review of high temperature design guidelines has been carried out in preparation for designing a solar storage module for the Freedom Spacelab. Three major guidelines, N47, R5 and RCC-MR form the basis of the survey. The main issues with current, mature design in the power industry appear to be adequately covered by these guidelines. A significant finding is that long established models of material damage have survived the test of time very well. A new design regime referred to as Very High Temperature Design (VHTD) is identified. The characteristics of this regime are changing material properties which require some changes in philosophy in drafting of future codes, particularly in regard to definitions of yield strengths and other design allowables. Finally, there is some discussion of the more general use of the stress/strain plane, e.g. isochronous curves, for representation of very complex material constitutive behaviour. A concept called the 'Relaxation Locus', which summarizes essential local constrained component behavior, is introduced and its application to high temperature design problems is discussed briefly. (author).

  4. Laser Plasma Coupling for High Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W.

    1999-11-04

    Simple scaling models indicate that quite high radiation temperatures can be achieved in hohlraums driven with the National Ignition Facility. A scaling estimate for the radiation temperature versus pulse duration for different size NIF hohlraums is shown in Figure 1. Note that a radiation temperature of about 650 ev is projected for a so-called scale 1 hohlraum (length 2.6mm, diameter 1.6mm). With such high temperature hohlraums, for example, opacity experiments could be carried out using more relevant high Z materials rather than low Z surrogates. These projections of high temperature hohlraums are uncertain, since the scaling model does not allow for the very strongly-driven laser plasma coupling physics. Lasnex calculations have been carried out to estimate the plasma and irradiation conditions in a scale 1 hohlraum driven by NIF. Linear instability gains as high as exp(100) have been found for stimulated Brillouin scattering, and other laser-driven instabilities are also far above their thresholds. More understanding of the very strongly-driven coupling physics is clearly needed in order to more realistically assess and improve the prospects for high temperature hohlraums. Not surprisingly, this regime has been avoided for inertial fusion applications and so is relatively unexplored.

  5. High temperature mechanical properties of iron aluminides

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2001-04-01

    Full Text Available Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the material, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered.

    Durante los últimos años se ha prestado mucha atención a la familia de intermetálicos Fe-Al, puesto que estos constituyen un considerable potencial como materiales de ingeniería en aplicaciones a temperaturas intermedias o altas, sobre todo en casos donde se necesita alta resistencia a la oxidación o corrosión. A pesar del considerable esfuerzo desarrollado para obtener aleaciones con mejores propiedades, su resistencia mecánica a alta temperatura no es muy elevada. Se discutirán los aspectos que contribuyen a la baja resistencia mecánica a temperatura elevada en función de la estructura de dislocaciones y los mecanismos de anclaje que operan en este intermetálico. Se considerarán, también, maneras alternativas para mejorar la resistencia a temperatura elevada mediante la modificación de la microestructura y la incorporación de partículas de segunda fase.

  6. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    The aim of this workshop is to share the needs of high temperature and nuclear fuel materials for future nuclear systems, to take stock of the status of researches in this domain and to propose some cooperation works between the different research organisations. The future nuclear systems are the very high temperature (850 to 1200 deg. C) gas cooled reactors (GCR) and the molten salt reactors (MSR). These systems include not only the reactor but also the fabrication and reprocessing of the spent fuel. This document brings together the transparencies of 13 communications among the 25 given at the workshop: 1) characteristics and needs of future systems: specifications, materials and fuel needs for fast spectrum GCR and very high temperature GCR; 2) high temperature materials out of neutron flux: thermal barriers: materials, resistance, lifetimes; nickel-base metal alloys: status of knowledge, mechanical behaviour, possible applications; corrosion linked with the gas coolant: knowledge and problems to be solved; super-alloys for turbines: alloys for blades and discs; corrosion linked with MSR: knowledge and problems to be solved; 3) materials for reactor core structure: nuclear graphite and carbon; fuel assembly structure materials of the GCR with fast neutron spectrum: status of knowledge and ceramics and cermets needs; silicon carbide as fuel confinement material, study of irradiation induced defects; migration of fission products, I and Cs in SiC; 4) materials for hydrogen production: status of the knowledge and needs for the thermochemical cycle; 5) technologies: GCR components and the associated material needs: compact exchangers, pumps, turbines; MSR components: valves, exchangers, pumps. (J.S.)

  7. Radiation Shielding Utilizing A High Temperature Superconducting Magnet Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This project aims to leverage near-term high-temperature superconducting technologies to assess applicability of magnetic shielding for protecting against exposure...

  8. Novel High Temperature Membrane for PEM Fuel Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation proposed in this STTR program is a high temperature membrane to increase the efficiency and power density of PEM fuel cells. The NASA application is...

  9. Quench in high temperature superconductor magnets

    CERN Document Server

    Schwartz, J

    2013-01-01

    High field superconducting magnets using high temperature superconductors are being developed for high energy physics, nuclear magnetic resonance and energy storage applications. Although the conductor technology has progressed to the point where such large magnets can be readily envisioned, quench protection remains a key challenge. It is well-established that quench propagation in HTS magnets is very slow and this brings new challenges that must be addressed. In this paper, these challenges are discussed and potential solutions, driven by new technologies such as optical fiber based sensors and thermally conducting electrical insulators, are reviewed.

  10. A Generalized Fluid Formulation for Turbomachinery Computations

    Science.gov (United States)

    Merkle, Charles L.; Sankaran, Venkateswaran; Dorney, Daniel J.; Sondak, Douglas L.

    2003-01-01

    A generalized formulation of the equations of motion of an arbitrary fluid are developed for the purpose of defining a common iterative algorithm for computational procedures. The method makes use of the equations of motion in conservation form with separate pseudo-time derivatives used for defining the numerical flux for a Riemann solver and the convergence algorithm. The partial differential equations are complemented by an thermodynamic and caloric equations of state of a complexity necessary for describing the fluid. Representative solutions with a new code based on this general equation formulation are provided for three turbomachinery problems. The first uses air as a working fluid while the second uses gaseous oxygen in a regime in which real gas effects are of little importance. These nearly perfect gas computations provide a basis for comparing with existing perfect gas code computations. The third case is for the flow of liquid oxygen through a turbine where real gas effects are significant. Vortex shedding predictions with the LOX formulations reduce the discrepancy between perfect gas computations and experiment by approximately an order of magnitude, thereby verifying the real gas formulation as well as providing an effective case where its capabilities are necessary.

  11. High-temperature beryllium embrittlement

    Energy Technology Data Exchange (ETDEWEB)

    Pokrovsky, A.S. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation); Fabritsiev, S.A. [D.V. Efremov Scientific Research Institute, 189631 St. Petersburg (Russian Federation); Bagautdinov, R.M. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation); Goncharenko, Yu.D. [Scientific Research Inst. of Atomic Reactors, Dimitrovgrad (Russian Federation)

    1996-10-01

    The neutron irradiation effect on the mechanical properties, swelling and fracture surface structure of various beryllium grades was studied in the BOR-60 reactor at 340 to 350 C up to a fluence of 7.2 x 10{sup 21} n/cm{sup 2}. At a mechanical testing temperature of 400 C there was observed a strong anisotropy of plastic beryllium deformation depending on the direction of sample cutting relative to the pressing direction. An increase of the testing temperature up to 700 C resulted in an abrupt embrittlement of all irradiated samples. In the most part of the surface structure the intercrystallite fracture along the grain boundaries was covered entirely with large pores, 1 to 4 {mu}m in size. It was suggested that the increased rate of pore formation along the grain boundaries resulted from a high-temperature embrittlement under irradiation. (orig.).

  12. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  13. High temperature control rod assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vollman, Russell E. (Solana Beach, CA)

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  14. High-temperature process-steam application at the Southern Union Refining Company, Hobbs, New Mexico (solar energy in the oil patch). Phase I design. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1979-07-31

    Southern Union Refining Company's Famariss Energy Refinery has worked diligently with Monument Solar Corporation in the conceptual and detail design for this unique application of solar generated steam. An area closely adjacent to the refinery and fronting New Mexico State Highway No. 18 has been designated for the solar collector array. Space planned for the demonstration parabolic trough array is sufficiently large to handle an array of 25,200 square feet in size - an array more than twice the size of the 10,080 square feet proposed originally. The conceptual design, performance, safety, environmental impact, and economic analysis are described. Engineering drawings are included. (WHK)

  15. Condition Monitoring of Blade in Turbomachinery: A Review

    Directory of Open Access Journals (Sweden)

    Ahmed M. Abdelrhman

    2014-03-01

    Full Text Available Blade faults and blade failures are ranked among the most frequent causes of failures in turbomachinery. This paper provides a review on the condition monitoring techniques and the most suitable signal analysis methods to detect and diagnose the health condition of blades in turbomachinery. In this paper, blade faults are categorised into five types in accordance with their nature and characteristics, namely, blade rubbing, blade fatigue failure, blade deformations (twisting, creeping, corrosion, and erosion, blade fouling, and loose blade. Reviews on characteristics and the specific diagnostic methods to detect each type of blade faults are also presented. This paper also aims to provide a reference in selecting the most suitable approaches to monitor the health condition of blades in turbomachinery.

  16. Study on Aerodynamic Design Optimization of Turbomachinery Blades

    Institute of Scientific and Technical Information of China (English)

    Naixing CHEN; Hongwu ZHANG; Weiguang HUANG; Yanji XU

    2005-01-01

    This paper describes the study on aerodynamics design optimization of turbomachinery blading developed by the authors at the Institute of Engineering Thermophysics, Chinese Academy of Sciences, during the recent few years. The present paper describes the aspects mainly on how to use a rapid approach of profiling a 3D blading and of grid generation for computation, a fast and accurate viscous computation method and an appropriate optimization methodology_ including a blade parameterization algorithm to optimize turbomachinery blading aerodynamically. Any blade configuration can be expressed by three curves, they are the camber lines, the thickness distributions and the radial stacking line, and then the blade geometry can be easily parameterized by a number of parameters with three polynomials. A gradient-based parameterization analytical method and a response surface method were applied herein for blade optimization. It was found that the optimization process provides reliable design for turbomachinery with reasonable computing time.

  17. Solving Incompressible Internal Flow Fields in Turbomachinery with Time Marching Algorithms

    Institute of Scientific and Technical Information of China (English)

    ZhuWei; SuoYisheng; 等

    1999-01-01

    A time marching algorithms,which is used to solve incomprssible internal flow fields in turbomachinery,has been developed.By using Chorin's method of artificial compressibility,the governing equations are transformed from elliptic type into hyperbolic form in order to extend the time marching technique to very low Mach number flows.Viscous effects can be predicted by using the distributed body force method and Baldwin-Lomax eddy viscosity turbulence model.Some accelerating convergence techniques such as multi-grid and local time step method are employed.The application to a flow field within a low-solidity rocket pump inducer is presented and discussed.

  18. Is the empirical approximation Y/G approx constant applicable to high-pressure and high-temperature environments for metals?

    CERN Document Server

    Hua, J S; Hua, T; Hu, S L

    2002-01-01

    Recently, we have found, by means of a shock wave experiment, that an empirical relation Y/G approx 1.9x10 sup - sup 2 (Y is the yield strength and G is the shear modulus) is applicable for describing the strength effect for shocked 93W (93% W with 7% Fe-Ni-Co as binder) in the pressure range up to 150 GPa. This represents an extension of existing knowledge of the empirical approximation Y/G approx constant for potassium obtained at liquid-N sub 2 temperature and in the pressure range below 0.55 GPa. This approximation is advantageous in allowing one to simply and conveniently construct the constitutive equation for shocked metals.

  19. Modeling and optimization of a heat-pump-assisted high temperature proton exchange membrane fuel cell micro-combined-heat-and-power system for residential applications

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Kær, Søren Knudsen; Nielsen, Mads Pagh

    2015-01-01

    In this study a micro-combined-heat-and-power (micro-CHP) system is coupled to a vapor-compression heat pump to fulfill the residential needs for heating (space heating and water heating) and electricity in detached single-family households in Denmark. Such a combination is assumed to be attractive...... for application, since both fuel cell technology and electric heat pumps are found to be two of the most efficient technologies for generation/conversion of useful energy. The micro-CHP system is fueled with natural gas and includes a fuel cell stack, a fuel processor and other auxiliary components. The micro....... The variational loads are considered from full to quarter load, and the micro-CHP system is optimized in terms of operating thermophysical parameters for every different load. The results clearly indicate the capability of the proposed system to perform efficiently throughout all necessary load changes to fulfill...

  20. The NASA high temperature superconductivity program

    Science.gov (United States)

    Sokoloski, Martin M.; Romanofsky, Robert R.

    1990-01-01

    It has been recognized from the onset that high temperature superconductivity held great promise for major advances across a broad range of NASA interests. The current effort is organized around four key areas: communications and data, sensors and cryogenics, propulsion and power, and space materials technology. Recently, laser ablated YBa2Cu3O(7-x) films on LaAIO produced far superior RF characteristics when compared to metallic films on the same substrate. This achievement has enabled a number of unique microwave device applications, such as low insertion loss phase shifters and high Q filters. Melt texturing and melt quenched techniques are being used to produce bulk materials with optimized magnetic properties. These yttrium enriched materials possess enhanced flux pinning characteristics and will lead to prototype cryocooler bearings. Significant progress has also occurred in bolometer and current lead technology. Studies are being conducted to evaluate the effect of high temperature superconducting materials on the performance and life of high power magneto-plasma-dynamic thrusters. Extended studies were also performed to evaluate the benefit of superconducting magnetic energy storage for LEO space station, lunar and Mars mission applications. The project direction and level of effort of the program are also described.