WorldWideScience

Sample records for bubbleless gas transfer

  1. Liquefied Natural Gas Transfer

    Science.gov (United States)

    1980-01-01

    Chicago Bridge & Iron Company's tanks and associated piping are parts of system for transferring liquefied natural gas from ship to shore and storing it. LNG is a "cryogenic" fluid meaning that it must be contained and transferred at very low temperatures, about 260 degrees below Fahrenheit. Before the LNG can be pumped from the ship to the storage tanks, the two foot diameter transfer pipes must be cooled in order to avoid difficulties associated with sharp differences of temperature between the supercold fluid and relatively warm pipes. Cooldown is accomplished by sending small steady flow of the cryogenic substance through the pipeline; the rate of flow must be precisely controlled or the transfer line will be subjected to undesirable thermal stress.

  2. Production of surfactin and fengycin by Bacillus subtilis in a bubbleless membrane bioreactor.

    Science.gov (United States)

    Coutte, François; Lecouturier, Didier; Yahia, Saliha Ait; Leclère, Valérie; Béchet, Max; Jacques, Philippe; Dhulster, Pascal

    2010-06-01

    Surfactin and fengycin are lipopeptide biosurfactants produced by Bacillus subtilis. This work describes for the first time the use of bubbleless bioreactors for the production of these lipopeptides by B. subtilis ATCC 21332 with aeration by a hollow fiber membrane air-liquid contactor to prevent foam formation. Three different configurations were tested: external aeration module made from either polyethersulfone (reactor BB1) or polypropylene (reactor BB2) and a submerged module in polypropylene (reactor BB3). Bacterial growth, glucose consumption, lipopeptide production, and oxygen uptake rate were monitored during the culture in the bioreactors. For all the tested membranes, the bioreactors were of satisfactory bacterial growth and lipopeptide production. In the three configurations, surfactin production related to the culture volume was in the same range: 242, 230, and 188 mg l(-1) for BB1, BB2, and BB3, respectively. Interestingly, high differences were observed for fengycin production: 47 mg l(-1) for BB1, 207 mg l(-1) for BB2, and 393 mg l(-1) for BB3. A significant proportion of surfactin was adsorbed on the membranes and reduced the volumetric oxygen mass transfer coefficient. The degree of adsorption depended on both the material and the structure of the membrane and was higher with the submerged polypropylene membrane.

  3. Gas and liquid transfer

    Energy Technology Data Exchange (ETDEWEB)

    Shimura, T.; Asano, H. [RWMC, Minato-ku, Tokyo (Japan); Vomvoris, S.; Marschall, P. [NAGRA, Wettingen (Switzerland); Lanyon, G.W. [Fracture Systems Ltd, Tregurrian, St Ives (United Kingdom); Ando, K.; Yamamoto, S. [Obayashi Corporation, Shinagawa Intercity Tower B, Minato-ku, Tokyo (Japan); Senger, R. [INTERA Incorporated, Austin, Texas (United States); Xu, T.; Finsterle, S. [Lawrence Berkeley National Lab., Earth Sciences Div., Berkeley, CA (United States); Alkan, H.; Muller, W [Istec, Institute for Safety Technology, Cologne (Germany); Rousseau-Gueutin, P.; Goncalves, J.; Violette, S. [UMR 7619 Sisyphe, 75 - Paris (France); Rousseau-Gueutin, P.; Cruchaudet, M. [Agence Nationale pour la Gestion des Dechets Radioactifs, Lab. de Souterrain de Meuse/Haute-Marne, 55 - Bure (France); Altmann, S.; Enachescu, C.; Delay, J.; Cruchaudet, M.; Vaissiere, R. de la [ANDRA - Agence Nationale pour la Gestion des Dechets Radioactifs, 92 - Chatenay Malabry (France); Greef, V. de [UMR 7649 LMS, 91 - Palaiseau (France); Montavon, G.; Alhajji, E.; Guo, Z. [Subatech laboratory, 44 - Nantes (France); Lebotlan, D.; Grambow, B. [LAIEM, 44 - Nantes (France); Tournassat, C. [Bureau de Recherches Geologiques et Minieres (BRGM), 45 - Orleans (France)

    2007-07-01

    This session gathers 6 articles dealing with: gas migration through bentonite/sand: Lessons learned from the GMT in-situ test (T. Shimura, S. Vomvoris, G.W. Lanyon, P. Marschall, K. Ando, S. Yamamoto, H. Asano); the modeling approaches of two-phase flow phenomena associated with corrosion of SF/HLW canisters in a proposed repository in Opalinus clay, Switzerland (R. Senger, T. Xu, P. Marschall, S. Finsterle); the approaches for modelling gas transport in clay formations based on improved Darcy and non-Darcy flow concepts (H. Alkan, W. Mueller); deriving large scale hydraulic behaviour from borehole pressure history data (C. Enachescu, J. Delay, M. Cruchaudet, R. de la Vaissiere); the interpretation of interstitial pressures in clay media: Application to the Callovo-Oxfordian (P. Rousseau-Gueutin, J. Goncalves, M. Cruchaudet, S. Altmann, V. de Greef, S. Violette); and the porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the states of water (G. Montavon, E. Alhajji, D. Lebotlan, Z. Guo, C. Tournassat, B. Grambow)

  4. Heat Transfer in Gas Turbines

    Science.gov (United States)

    Garg, Vijay K.

    2001-01-01

    The turbine gas path is a very complex flow field. This is due to a variety of flow and heat transfer phenomena encountered in turbine passages. This manuscript provides an overview of the current work in this field at the NASA Glenn Research Center. Also, based on the author's preference, more emphasis is on the computational work. There is much more experimental work in progress at GRC than that reported here. While much has been achieved, more needs to be done in terms of validating the predictions against experimental data. More experimental data, especially on film cooled and rough turbine blades, are required for code validation. Also, the combined film cooling and internal cooling flow computation for a real blade is yet to be performed. While most computational work to date has assumed steady state conditions, the flow is clearly unsteady due to the presence of wakes. All this points to a long road ahead. However, we are well on course.

  5. Scaling of heat transfer in gas-gas injector combustor

    Institute of Scientific and Technical Information of China (English)

    Wang Xiao-Wei; Cai Guo-Biao; Gao Yu-Shan

    2011-01-01

    The scaling of heat transfer in gas-gas injector combuetor is investigated theoretically, numerically and experimentally based on the previous study on the scaling of gas-gas combustion flowfield. The similarity condition of the gas-gas injector combustor heat transfer is obtained by conducting a formulation analysis of the boundary layer Navier-Stokes equations and a dimensional analysis of the corresponding heat transfer phenomenon. Then, a practicable engineering scaling criterion of the gas-gas injector combustor heat transfer is put forward. The criterion implies that when the similarity conditions of inner flowfield are satisfied, the size and the pressure of gas-gas combustion chamber can be changed, while the heat transfer can still be qualitatively similar to the distribution trend and quantitatively correlates well with the size and pressure as q ∝ pc0.8dt-0.2. Based on the criterion, single-element injector chambers with different geometric sizes and at different chamber pressures ranging from 1 MPa to 20 MPa are numerically simulated. A single-element injector chamber is designed and hot-fire tested at seven chamber pressures from 0.92 MPa to 6.1 MPa.The inner wall heat flux are obtained and analysed. The numerical and experimental results both verified the scaling criterion in gas-gas injector combustion chambers under different chamber pressures and geometries.

  6. Novel Water Treatment Processes Based on Hybrid Membrane-Ozonation Systems: A Novel Ceramic Membrane Contactor for Bubbleless Ozonation of Emerging Micropollutants

    Directory of Open Access Journals (Sweden)

    Stylianos K. Stylianou

    2015-01-01

    Full Text Available The aim of this study is the presentation of novel water treatment systems based on ozonation combined with ceramic membranes for the treatment of refractory organic compounds found in natural water sources such as groundwater. This includes, firstly, a short review of possible membrane based hybrid processes for water treatment from various sources. Several practical and theoretical aspects for the application of hybrid membrane-ozonation systems are discussed, along with theoretical background regarding the transformation of target organic pollutants by ozone. Next, a novel ceramic membrane contactor, bringing into contact the gas phase (ozone and water phase without the creation of bubbles (bubbleless ozonation, is presented. Experimental data showing the membrane contactor efficiency for oxidation of atrazine, endosulfan, and methyl tert-butyl ether (MTBE are shown and discussed. Almost complete endosulfan degradation was achieved with the use of the ceramic contactor, whereas atrazine degradation higher than 50% could not be achieved even after 60 min of reaction time. Single ozonation of water containing MTBE could not result in a significant MTBE degradation. MTBE mineralization by O3/H2O2 combination increased at higher pH values and O3/H2O2 molar ratio of 0.2 reaching a maximum of around 65%.

  7. Gas transfer in a bubbly wake flow

    Science.gov (United States)

    Karn, A.; Gulliver, J. S.; Monson, G. M.; Ellis, C.; Arndt, R. E. A.; Hong, J.

    2016-05-01

    The present work reports simultaneous bubble size and gas transfer measurements in a bubbly wake flow of a hydrofoil, designed to be similar to a hydroturbine blade. Bubble size was measured by a shadow imaging technique and found to have a Sauter mean diameter of 0.9 mm for a reference case. A lower gas flow rate, greater liquid velocities, and a larger angle of attack all resulted in an increased number of small size bubbles and a reduced weighted mean bubble size. Bubble-water gas transfer is measured by the disturbed equilibrium technique. The gas transfer model of Azbel (1981) is utilized to characterize the liquid film coefficient for gas transfer, with one scaling coefficient to reflect the fact that characteristic turbulent velocity is replaced by cross-sectional mean velocity. The coefficient was found to stay constant at a particular hydrofoil configuration while it varied within a narrow range of 0.52-0.60 for different gas/water flow conditions.

  8. Mass transfer in gas-liquid slurry reactors

    NARCIS (Netherlands)

    Beenackers, A.A.C.M.; Swaaij, van W.P.M.

    1993-01-01

    A critical review is presented on the mass transfer characteristics of gas¿liquid slurry reactors. The recent findings on the influence of the presence of solid particles on the following mass transfer parameters in slurry reactors are discussed: volumetric gas¿liquid mass transfer coefficients (kLa

  9. Review of mass transfer aspects for biological gas treatment

    NARCIS (Netherlands)

    Kraakman, N.J.R.; Rocha-Rios, J.; Van Loosdrecht, M.C.M.

    2011-01-01

    This contribution reviews the mass transfer aspects of biotechnological processes for gas treatment, with an emphasis on the underlying principles and technical feasible methods for mass transfer enhancements. Understanding of the mass transfer behavior in bioreactors for gas treatment will result i

  10. MASS-TRANSFER IN GAS-LIQUID SLURRY REACTORS

    NARCIS (Netherlands)

    BEENACKERS, AACM; VANSWAAIJ, WPM

    1993-01-01

    A critical review is presented on the mass transfer characteristics of gas-liquid slurry reactors. The recent findings on the influence of the presence of solid particles on the following mass transfer parameters in slurry reactors are discussed: volumetric gas-liquid mass transfer coefficients (k(L

  11. Gas turbine heat transfer and cooling technology

    CERN Document Server

    Han, Je-Chin; Ekkad, Srinath

    2012-01-01

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

  12. Heat Transfer in Flue Gas with Vapor Condensation

    Institute of Scientific and Technical Information of China (English)

    贾力; 彭晓峰

    2002-01-01

    This paper combines the film model with Nusselt's condensation theory to analyze the effects of water vapor condensation on the heat transfer performance of flue gas flowing through a vertical tube. The analysis compares the condensation and convective heat transfer rates. For the concentration range investigated, the water vapor condensation transfers more energy than the flue gas convection, but the convective heat transfer can not be neglected. The heat transfer intensification due to the condensation increased as the water vapor fraction increased. The theoretical results compared well with experimental data.

  13. Optimising Gas Quenching Technology through Modelling of Heat Transfer

    Institute of Scientific and Technical Information of China (English)

    Florent Chaffotte; Linda L(e)fevre; Didier Domergue; Aymeric Goldsteinas; Xavier Doussot; Qingfei Zhang

    2004-01-01

    Gas Quenching represents an environmentally friendly alternative to more commonly-used oil quenching. Yet,the performances of this technology remain limited in terms of cooling rates reached compared to oil quenching. Distortion and process homogeneity also have to be controlled carefully. The efficiency of the gas quenching process fully depends on the heat transfer between the gas and the quenched parts. The goal of this study is the optimisation of the gas quenching process efficiency through a better understanding of the heat transfer phenomena involved. The study has been performed with modelling means and validated by an experimental approach. The configuration of the gas flow has a major influence on the heat transfer phenomena between the gas and the parts. The fluid dynamics modelling approach performed in this study allows to optimise the heat transfer phenomena. New gas quenching processes allowing enhanced gas quenching performance through higher cooling rates can be thereby identified. The new solutions have been validated in experimental and industrial conditions. Results obtained allow to expect significant improvement of high pressure gas quenching technology.

  14. Optimising Gas Quenching Technology through Modelling of Heat Transfer

    Institute of Scientific and Technical Information of China (English)

    FiorentChaffotte; LindaLefevre; DidierDomergue; AymericGoidsteinas; XavierDoussot; QingfeiZhang

    2004-01-01

    Gas Quenching represents an environmentally friendly alternative to more commonly-used oil quenching. Yet,the performances of this technology remain limited in terms of cooling rates reached compared to oil quenching. Distortion and process homogeneity also have to be controlled carefully. The efficiency of the gas quenching process fully depends on the heat transfer between the gas and the quenched parts. The goal of this study is the optimisation of the gas quenching process efficiency through a better understanding of the heat transfer phenomena involved. The study has been performed with modelling means and validated by an experimental approach. ThE configuration of the gas flow has a major influence on the heat transfer phenomena between the gas and the parts. The fluid dynamics modelling approach performed in this study allows to optimise the heat transfer phenomena. New gas quenching processes allowing enhanced gas quenching performance through higher cooling rates can be thereby identified. The new solutions have been validated in experimental and industrial conditions. Results obtained allow to expect significant improvement of high pressure gas quenching technology.

  15. Enhancement of gas phase heat transfer by acoustic field application.

    Science.gov (United States)

    Komarov, Sergey; Hirasawa, Masahiro

    2003-06-01

    This study discusses a possibility for enhancement of heat transfer between solids and ambient gas by application of powerful acoustic fields. Experiments are carried out by using preheated Pt wires (length 0.1-0.15 m, diameter 50 and 100 micro m) positioned at the velocity antinode of a standing wave (frequency range 216-1031 Hz) or in the path of a travelling wave (frequency range 6.9-17.2 kHz). A number of experiments were conducted under conditions of gas flowing across the wire surface. Effects of sound frequency, sound strength, gas flow velocity and wire preheating temperature on the Nusselt number are examined with and without sound application. The gas phase heat transfer rate is enhanced with acoustic field strength. Higher temperatures result in a vigorous radiation from the wire surface and attenuate the effect of sound. The larger the gas flow velocity, the smaller is the effect of sound wave on heat transfer enhancement.

  16. The Mechanism of Interfacial Mass Transfer in Gas Absorption Process

    Institute of Scientific and Technical Information of China (English)

    马友光; 冯惠生; 徐世昌; 余国琮

    2003-01-01

    Based on the method of molecular thermodynamics ,the mass transfer mechanism at gas-liquid interface is studied theoretically,and a nowe mathematical model is proposed,Using laser holographic interference technique,the hydrodynamics and mass transfer characteristics of CO2 absorption are measured,It is shown that the calculated results are in good agreement with the experimental data.

  17. Burnett simulations of gas flow and heat transfer in microchannels

    Institute of Scientific and Technical Information of China (English)

    Fubing BAO; Jianzhong LIN

    2009-01-01

    In micro- and nanoscale gas flows, the flow falls into the transition flow regime. There are not enough molecule collisions and the gas deviates from the equilibrium. The Navier-Stokes equations fail to describe the gas flow in this regime. The direct simulation Monte Carlo method converges slowly and requires lots of computational time. As a result, the high-order Burnett equations are used to study the gas flow and heat transfer characteristics in micro- and nanoscale gas flows in this paper. The Burnett equations are first reviewed, and the augmented Burnett equations with high-order slip bound-ary conditions are then used to model the gas flow and heat transfer in Couette and Poiseuille flows in the transition regime.

  18. Gathering and Transferring Project for Datianchi Gas Field Completed

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    @@ The surface gathering and transferring project for Datianchi structure passed the examination on May 24, signaling completion of the seven-year-old largescale natural gas transmission project. This project will provide additional 8 million cubic meters of natural gas to the markets in Sichuan-Chongqing area each day, paving the way for long-distance transmission of natural gas from this area to Jianghan plain.

  19. Heat transfer to finned tubes exposed to hot waste gas

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, E.; Kremer, H.

    1975-05-01

    Transfer of heat by forced convection to finned tubes, particularly to those with an elliptical center pipe, is described. These pipes are used in gas-fired water heaters, boilers, and heat exchangers. Finned tubes in a test tunnel were exposed to a stream of waste gas from a gas/air mixture at different Reynolds numbers. Mathematical relationships showing the dependence of the Nusselt number on the Reynolds number and on the geometry of the tubes were derived. The single pipe showed a significant drop in the heat-transfer coefficient as the gap between fins became closer. The results of the measurement of heat transfer by forced convection to finned tubes were expressed in a standard form for all tubes. The same heat transfer law can be applied to electrically heated finned tubes exposed to a stream of cooling air.

  20. Membrane-based gas transfer: an environmental engineering laboratory.

    Science.gov (United States)

    Kilduff, J; Liu, J X; Komisar, S J

    2004-01-01

    We propose an educational experience in which students design a membrane gas transfer reactor, construct a bench-scale version in the laboratory, and employ the reactor to measure mass transfer coefficients. The membrane reactor is useful for teaching mass transfer principles because the mass transfer interface is well defined and easily observed. The system can be modeled successfully using straightforward mathematics. The reactor can be designed and constructed by students, using the mathematical model as a basis, providing insight into the physical meaning of model parameters. The proposed membrane system can be readily operated to obtain data that can be employed to develop or modify existing mass transfer correlations. This can provide students with significant insight into the development of mass transfer correlations and how the constants in such correlations are typically determined. These features help promote a deeper understanding of mass transfer principles.

  1. Gas-liquid mass transfer : influence of sparger location

    OpenAIRE

    Sardeing, Rodolphe; Aubin, Joelle; Poux, Martine; Xuereb, Catherine

    2004-01-01

    The performance of three sparger diameters (DS = 0.6D, DS = D, DS = 1.6D) in combination with three positions (below, above or level with the impeller) for gas-liquid dispersion and mass transfer were evaluated in the case of the Rushton turbine and the A315 propeller in up- or down-pumping mode. The results show that the best results in terms of gas handling and mass transfer capacities are obtained for all impellers with the sparger placed below it and with a diameter at least e...

  2. Heat transfer across the interface between nanoscale solids and gas.

    Science.gov (United States)

    Cheng, Chun; Fan, Wen; Cao, Jinbo; Ryu, Sang-Gil; Ji, Jie; Grigoropoulos, Costas P; Wu, Junqiao

    2011-12-27

    When solid materials and devices scale down in size, heat transfer from the active region to the gas environment becomes increasingly significant. We show that the heat transfer coefficient across the solid-gas interface behaves very differently when the size of the solid is reduced to the nanoscale, such as that of a single nanowire. Unlike for macroscopic solids, the coefficient is strongly pressure dependent above ∼10 Torr, and at lower pressures it is much higher than predictions of the kinetic gas theory. The heat transfer coefficient was measured between a single, free-standing VO(2) nanowire and surrounding air using laser thermography, where the temperature distribution along the VO(2) nanowire was determined by imaging its domain structure of metal-insulator phase transition. The one-dimensional domain structure along the nanowire results from the balance between heat generation by the focused laser and heat dissipation to the substrate as well as to the surrounding gas, and thus serves as a nanoscale power-meter and thermometer. We quantified the heat loss rate across the nanowire-air interface, and found that it dominates over all other heat dissipation channels for small-diameter nanowires near ambient pressure. As the heat transfer across the solid-gas interface is nearly independent of the chemical identity of the solid, the results reveal a general scaling relationship for gaseous heat dissipation from nanostructures of all solid materials, which is applicable to nanoscale electronic and thermal devices exposed to gaseous environments.

  3. Air-sea transfer of gas phase controlled compounds

    Science.gov (United States)

    Yang, M.; Bell, T. G.; Blomquist, B. W.; Fairall, C. W.; Brooks, I. M.; Nightingale, P. D.

    2016-05-01

    Gases in the atmosphere/ocean have solubility that spans several orders of magnitude. Resistance in the molecular sublayer on the waterside limits the air-sea exchange of sparingly soluble gases such as SF6 and CO2. In contrast, both aerodynamic and molecular diffusive resistances on the airside limit the exchange of highly soluble gases (as well as heat). Here we present direct measurements of air-sea methanol and acetone transfer from two open cruises: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The transfer of the highly soluble methanol is essentially completely airside controlled, while the less soluble acetone is subject to both airside and waterside resistances. Both compounds were measured concurrently using a proton-transfer-reaction mass spectrometer, with their fluxes quantified by the eddy covariance method. Up to a wind speed of 15 m s-1, observed air-sea transfer velocities of these two gases are largely consistent with the expected near linear wind speed dependence. Measured acetone transfer velocity is ∼30% lower than that of methanol, which is primarily due to the lower solubility of acetone. From this difference we estimate the “zero bubble” waterside transfer velocity, which agrees fairly well with interfacial gas transfer velocities predicted by the COARE model. At wind speeds above 15 m s-1, the transfer velocities of both compounds are lower than expected in the mean. Air-sea transfer of sensible heat (also airside controlled) also appears to be reduced at wind speeds over 20 m s-1. During these conditions, large waves and abundant whitecaps generate large amounts of sea spray, which is predicted to alter heat transfer and could also affect the air-sea exchange of soluble trace gases. We make an order of magnitude estimate for the impacts of sea spray on air-sea methanol transfer.

  4. Evaluating gas transfer velocity parameterizations using upper ocean radon distributions

    Science.gov (United States)

    Bender, Michael L.; Kinter, Saul; Cassar, Nicolas; Wanninkhof, Rik

    2011-02-01

    Sea-air fluxes of gases are commonly calculated from the product of the gas transfer velocity (k) and the departure of the seawater concentration from atmospheric equilibrium. Gas transfer velocities, generally parameterized in terms of wind speed, continue to have considerable uncertainties, partly because of limited field data. Here we evaluate commonly used gas transfer parameterizations using a historical data set of 222Rn measurements at 105 stations occupied on Eltanin cruises and the Geosecs program. We make this evaluation with wind speed estimates from meteorological reanalysis products (from National Centers for Environmental Prediction and European Centre for Medium-Range Weather Forecasting) that were not available when the 22Rn data were originally published. We calculate gas transfer velocities from the parameterizations by taking into account winds in the period prior to the date that 222Rn profiles were sampled. Invoking prior wind speed histories leads to much better agreement than simply calculating parameterized gas transfer velocities from wind speeds on the day of sample collection. For individual samples from the Atlantic Ocean, where reanalyzed winds agree best with observations, three similar recent parameterizations give k values for individual stations with an rms difference of ˜40% from values calculated using 222Rn data. Agreement of basin averages is much better. For the global data set, the average difference between k constrained by 222Rn and calculated from the various parameterizations ranges from -0.2 to +0.9 m/d (average, 2.9 m/d). Averaging over large domains, and working with gas data collected in recent years when reanalyzed winds are more accurate, will further decrease the uncertainties in sea-air fluxes.

  5. Gas-Liquid Mass Transfer Coefficient in Stirred Tank Reactors

    NARCIS (Netherlands)

    Yawalkar, Archis A.; Heesink, Albertus B.M.; Versteeg, Geert F.; Pangarkar, Vishwas G.

    2002-01-01

    Volumetric gas—liquid mass transfer coefficient (kLa) data available in the literature for larger tanks (T = 0.39 m to 2.7 m) have been analyzed on the basis of relative dispersion parameter, N/Ncd. It was observed that at a given superficial gas velocity (VG), kLa values were approximately the same

  6. Heat transfer and flow characteristics on a gas turbine shroud.

    Science.gov (United States)

    Obata, M; Kumada, M; Ijichi, N

    2001-05-01

    The work described in this paper is an experimental investigation of the heat transfer from the main flow to a turbine shroud surface, which may be applicable to ceramic gas turbines. Three kinds of turbine shrouds are considered with a flat surface, a taper surface and a spiral groove surface opposite to the blades in an axial flow turbine of actual turbo-charger. Heat transfer measurements were performed for the experimental conditions of a uniform heat flux or a uniform wall temperature. The effects of the inlet flow angle, rotational speed, and tip clearance on the heat transfer coefficient were clarified under on- and off-design flow conditions. The mean heat transfer coefficient was correlated to the blade Reynolds number and tip clearance, and compared with an experimental correlation and measurements of a flat surface. A comparison was also made for the measurement of static pressure distributions.

  7. Simulation of rarefied gas flow and heat transfer in microchannels

    Institute of Scientific and Technical Information of China (English)

    王娴; 王秋旺; 陶文铨; 郑平

    2002-01-01

    Analysis and simulation of rarefied nitrogen gas flow and heat transfer were performed with the Knusden number ranging from 0.05 to 1.0, using the direct simulation of Monte Carlo (DSMC) method. The influences of the Kn number and the aspect ratio on the gas temperature and wall heat flux in the microchannels were studied parametrically. The total and local heat fluxes of the microchannel walls varying with the channel inlet velocities were also investigated in detail. It was found that the Kn number and the aspect ratio greatly influence the heat transfer performance of microchannels, and both the channel inlet and outlet have higher heat fluxes while the heat flux in the middle part of channels is very low. It is also found that the inlet free stream flow velocity has small affect on the wall total heat flux while it changes the distribution of local heat flux.

  8. Trap For Noncondensable Gas In Heat-Transfer Fluid

    Science.gov (United States)

    Edelstein, Fred; Cordes, Bruce; Brown, Richard F.

    1990-01-01

    Trap acts as scrubber by removing noncondensable gas as it is generated slowly or released by outgassing in vapor/liquid heat-transfer system. Includes tube of stainless steel or other poorly thermally conductive material attached to tap on top of main vapor line where vapor flows toward condenser. Sub-cooled liquid from outlet of condenser cools upper end of tube below vapor temperature.

  9. Charge Transfer Properties Through Graphene Layers in Gas Detectors

    CERN Document Server

    Thuiner, P; Jackman, R.B.; Müller, H.; Nguyen, T.T.; Oliveri, E.; Pfeiffer, D.; Resnati, F.; Ropelewski, L.; Smith, J.A.; van Stenis, M.; Veenhof, R.

    2015-01-01

    Graphene is a single layer of carbon atoms arranged in a honeycomb lattice with remarkable mechanical, electrical and optical properties. For the first time graphene layers suspended on copper meshes were installed into a gas detector equipped with a gaseous electron multiplier. Measurements of low energy electron and ion transfer through graphene were conducted. In this paper we describe the sample preparation for suspended graphene layers, the testing procedures and we discuss the preliminary results followed by a prospect of further applications.

  10. Fundamental heat transfer research for gas turbine engines

    Science.gov (United States)

    Metzger, D. E. (Editor)

    1980-01-01

    Thirty-seven experts from industry and the universities joined 24 NASA Lewis staff members in an exchange of ideas on trends in aeropropulsion research and technology, basic analyses, computational analyses, basic experiments, near-engine environment experiments, fundamental fluid mechanics and heat transfer, and hot technology as related to gas turbine engines. The workshop proceedings described include pre-workshop input from participants, presentations of current activity by the Lewis staff, reports of the four working groups, and a workshop summary.

  11. Polyoxometalate-mediated electron transfer-oxygen transfer oxidation of cellulose and hemicellulose to synthesis gas.

    Science.gov (United States)

    Sarma, Bidyut Bikash; Neumann, Ronny

    2014-08-01

    Terrestrial plants contain ~70% hemicellulose and cellulose that are a significant renewable bioresource with potential as an alternative to petroleum feedstock for carbon-based fuels. The efficient and selective deconstruction of carbohydrates to their basic components, carbon monoxide and hydrogen, so called synthesis gas, is an important key step towards the realization of this potential, because the formation of liquid hydrocarbon fuels from synthesis gas are known technologies. Here we show that by using a polyoxometalate as an electron transfer-oxygen transfer catalyst, carbon monoxide is formed by cleavage of all the carbon-carbon bonds through dehydration of initially formed formic acid. In this oxidation-reduction reaction, the hydrogen atoms are stored on the polyoxometalate as protons and electrons, and can be electrochemically released from the polyoxometalate as hydrogen. Together, synthesis gas is formed. In a hydrogen economy scenario, this method can also be used to convert carbon monoxide to hydrogen.

  12. 77 FR 2293 - AmeriGas Propane, L.P., AmeriGas Propane, Inc., Energy Transfer Partners, L.P., and Energy...

    Science.gov (United States)

    2012-01-17

    ... AmeriGas Propane, L.P., AmeriGas Propane, Inc., Energy Transfer Partners, L.P., and Energy Transfer...'') with AmeriGas Propane, L.P. (``AmeriGas''), AmeriGas Propane, Inc., Energy Transfer Partners, L.P. (``ETP''), and Energy Transfer Partners GP, L.P. (``ETP GP''), which is designed to guard...

  13. An improvement of surfactin production by B. subtilis BBG131 using design of experiments in microbioreactors and continuous process in bubbleless membrane bioreactor.

    Science.gov (United States)

    Motta Dos Santos, Luiz Fernando; Coutte, François; Ravallec, Rozenn; Dhulster, Pascal; Tournier-Couturier, Lucie; Jacques, Philippe

    2016-10-01

    Culture medium elements were analysed by a screening DoE to identify their influence in surfactin specific production by a surfactin constitutive overproducing Bacillus subtilis strain. Statistics pointed the major enhancement caused by high glutamic acid concentrations, as well as a minor positive influence of tryptophan and glucose. Successively, a central composite design was performed in microplate bioreactors using a BioLector®, in which variations of these impressive parameters, glucose, glutamic acid and tryptophan concentrations were selected for optimization of product-biomass yield (YP/X). Results were exploited in combination with a RSM. In absolute terms, experiments attained an YP/X 3.28-fold higher than those obtained in Landy medium, a usual culture medium used for lipopeptide production by B. subtilis. Therefore, two medium compositions for enhancing biomass and surfactin specific production were proposed and tested in continuous regime in a bubbleless membrane bioreactor. An YP/X increase of 2.26-fold was observed in bioreactor scale.

  14. Utilization of heat pipes for transfer heat from the flue gas into the heat transfer medium

    Directory of Open Access Journals (Sweden)

    Lenhard Richard

    2014-03-01

    Full Text Available The contribution is listed possible application of heat pipes in systems for obtaining heat from flue gas of small heat sources. It is also stated in the contribution design an experimental device on which to study the impact of fill (the quantity, type of load at various temperature parameters (temperature heating and cooling thermal power transferred to the heat pipe. Is listed measurement methodology using heat pipes designed experimental facility, measurement results and analysis of the results obtained.

  15. CONVECTIVE HEAT TRANSFER IN CYCLONE DEVICE WITH EXTERNAL GAS RECIRCULATION

    Directory of Open Access Journals (Sweden)

    S. V. Karpov

    2016-01-01

    Full Text Available The article considers the convective heat transfer on the surface of a hollow cylinder or several billets in a cyclone device with the new principle of external gas recirculation. According to this principle, transport of coolant from the lateral surface of the chamber, where the temperature is the highest, in the axial region is being fulfilled due to the pressure drop between the wall and axial areas of cyclonic flow. Dependency analysis of average and local heat transfer coefficients from operational and geometrical parameters has been performed; the generalized similarity equations for the calculation of the latter have been suggested. It is demonstrated that in case of download of a cyclone chamber with several billets, the use of the considered scheme of the external recirculation due to the specific characteristics of aerodynamics practically does not lead to noticeable changes in the intensity of convective heat transfer. Both experimental data and the numerical simulation results obtained with the use of OpenFOAM platform were used in the work. The investigations fulfilled will expand the area of the use of cyclone heating devices.

  16. Ultrasonic investigation of hydrodynamics and mass transfer in a gas-liquid(-liquid) stirred vessel

    NARCIS (Netherlands)

    Cents, A. H. G.; Brilmant, D. W. F.; Versteeg, G. F.

    2005-01-01

    The rate of gas-liquid mass transfer is very important in several industrial chemical engineering applications. In many multi-phase reaction systems, however, the mechanism of mass transfer is not well understood. This is for instance the case in Gas-Liquid-Solid (G-L-S) and Gas-Liquid-Liquid (G-L-L

  17. 77 FR 10373 - Greenhouse Gas Reporting Program: Electronics Manufacturing: Revisions to Heat Transfer Fluid...

    Science.gov (United States)

    2012-02-22

    ... AGENCY 40 CFR Part 98 RIN 2060-AR09 Greenhouse Gas Reporting Program: Electronics Manufacturing... category of the Greenhouse Gas Reporting Rule related to fluorinated heat transfer fluids. More... INFORMATION CONTACT: Carole Cook, Climate Change Division, Office of Atmospheric Programs...

  18. Monte Carlo simulations of dense gas flow and heat transfer in micro- and nano-channels

    Institute of Scientific and Technical Information of China (English)

    WANG Moran; LI Zhixin

    2005-01-01

    The dense gas flow and heat transfer in micro- and nano-channels was simulated using the Enskog simulation Monte Carlo (ESMC) method. The results were compared with those from the direct simulation Monte Carlo (DSMC) method and from the consistent Boltzmann algorithm (CBA). The dense gas flow and heat transfer characteristics were thus analyzed. The results showed that when the gas density was large enough, the finite gas density effect on the flow and heat transfer cannot be ignored, which decreased the skin friction coefficient and changed the heat transfer characteristics on the channel wall surfaces.

  19. Heat transfer problems in gas-cooled solid blankets

    Energy Technology Data Exchange (ETDEWEB)

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

    1976-01-01

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

  20. Experience transfer in Norwegian oil and gas industry: Approaches and organizational mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Aase, Karina

    1997-12-31

    The main objective of this thesis has been to explore how experience transfer works in Norwegian oil and gas industry. This includes how the concept of experience transfer is defined, what the barriers to achieve experience transfer are, how the oil and gas companies address experience transfer, and how these approaches work. The thesis is organized in five papers: (1) describes how organizational members perceive experience transfer and then specifies the organizational and structural barriers that must be overcome to achieve efficient transfer. (2) discusses the organizational means an oil company implements to address experience transfer. (3) describes a process of improving and using requirement and procedure handbooks for experience transfer. (4) explores how the use of information technology influences experience transfer. (5) compares organizational members` perceptions of experience transfer means in an oil company and an engineering company involved in offshore development projects. 277 refs., 3 figs., 29 tabs.

  1. Two Heat-Transfer Improvements for Gas Liquefiers

    Science.gov (United States)

    Martin, Jerry L.

    2005-01-01

    Two improvements in heat-transfer design have been investigated with a view toward increasing the efficiency of refrigerators used to liquefy gases. The improvements could contribute to the development of relatively inexpensive, portable oxygen liquefiers for medical use. A description of the heat-transfer problem in a pulse-tube refrigerator is prerequisite to a meaningful description of the first improvement. In a pulse-tube refrigerator in particular, one of in-line configuration heat must be rejected from two locations: an aftercooler (where most of the heat is rejected) and a warm heat exchanger (where a small fraction of the total input power must be rejected as heat). Rejection of heat from the warm heat exchanger can be problematic because this heat exchanger is usually inside a vacuum vessel. When an acoustic-inertance tube is used to provide a phase shift needed in the pulse-tube cooling cycle, another problem arises: Inasmuch as the acoustic power in the acoustic-inertance tube is dissipated over the entire length of the tube, the gas in the tube must be warmer than the warm heat exchanger in order to reject heat at the warm heat exchanger. This is disadvantageous because the increase in viscosity with temperature causes an undesired increase in dissipation of acoustic energy and an undesired decrease in the achievable phase shift. Consequently, the overall performance of the pulse-tube refrigerator decreases with increasing temperature in the acoustic-inertance tube. In the first improvement, the acoustic-inertance tube is made to serve as the warm heat exchanger and to operate in an approximately isothermal condition at a lower temperature, thereby increasing the achievable phase shift and the overall performance of the refrigerator. This is accomplished by placing the acoustic-inertance tube inside another tube and pumping a cooling fluid (e.g., water) in the annular space between the tubes. Another benefit of this improvement is added flexibility of

  2. An automated gas exchange tank for determining gas transfer velocities in natural seawater samples

    Directory of Open Access Journals (Sweden)

    K. Schneider-Zapp

    2014-02-01

    Full Text Available In order to advance understanding of the role of seawater surfactants in the air–sea exchange of climatically active trace gases via suppression of the gas transfer velocity (kw, we constructed a fully automated, closed air-water gas exchange tank and coupled analytical system. The system allows water-side turbulence in the tank to be precisely controlled with an electronically operated baffle. Two coupled gas chromatographs and an integral equilibrator, connected to the tank in a continuous gas-tight system, allow temporal changes in the partial pressures of SF6, CH4 and N2O to be measured simultaneously in the tank water and headspace at multiple turbulence settings, during a typical experimental run of 3.25 h. PC software developed by the authors controls all operations and data acquisition, enabling the optimisation of experimental conditions with high reproducibility. The use of three gases allows three independent estimates of kw for each turbulence setting; these values are subsequently normalised to a constant Schmidt number for direct comparison. The normalised kw estimates show close agreement. Repeated experiments with MilliQ water demonstrate a typical measurement accuracy of 4% for kw. Experiments with natural seawater show that the system clearly resolves the effects on kw of spatial and temporal trends in natural surfactant activity. The system is an effective tool with which to probe the relationships between kw, surfactant activity and biogeochemical indices of primary productivity, and should assist in providing valuable new insights into the air–sea gas exchange process.

  3. An automated gas exchange tank for determining gas transfer velocities in natural seawater samples

    Directory of Open Access Journals (Sweden)

    K. Schneider-Zapp

    2014-07-01

    Full Text Available In order to advance understanding of the role of seawater surfactants in the air–sea exchange of climatically active trace gases via suppression of the gas transfer velocity (kw, we constructed a fully automated, closed air–water gas exchange tank and coupled analytical system. The system allows water-side turbulence in the tank to be precisely controlled with an electronically operated baffle. Two coupled gas chromatographs and an integral equilibrator, connected to the tank in a continuous gas-tight system, allow temporal changes in the partial pressures of SF6, CH4 and N2O to be measured simultaneously in the tank water and headspace at multiple turbulence settings, during a typical experimental run of 3.25 h. PC software developed by the authors controls all operations and data acquisition, enabling the optimisation of experimental conditions with high reproducibility. The use of three gases allows three independent estimates of kw for each turbulence setting; these values are subsequently normalised to a constant Schmidt number for direct comparison. The normalised kw estimates show close agreement. Repeated experiments with Milli-Q water demonstrate a typical measurement accuracy of 4% for kw. Experiments with natural seawater show that the system clearly resolves the effects on kw of spatial and temporal trends in natural surfactant activity. The system is an effective tool with which to probe the relationships between kw, surfactant activity and biogeochemical indices of primary productivity, and should assist in providing valuable new insights into the air–sea gas exchange process.

  4. Biological conversion of synthesis gas. Mass transfer/kinetic studies

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.; Basu, R.; Johnson, E.R.; Clausen, E.C.; Gaddy, J.L.

    1992-03-01

    Mass transfer and kinetic studies were carried out for the Rhodospirillum rubrum and Chlorobium thiosulfatophilum bacterial systems. R. rubrum is a photosynthetic anaerobic bacterium which catalyzes the biological water gas shift reaction: CO + H{sub 2}0 {yields} CO{sub 2} + H{sub 2}. C. thiosulfatophilum is also a H{sub 2}S and COS to elemental sulfur. The growth of R. rubrum may be satisfactorily carried out at 25{degree} and 30{degree}C, while CO uptake and thus the conversion of CO best occurs at temperatures of either 30{degree}, 32{degree} or 34{degree}C. The rate of conversion of COs and H{sub 2}O to CO{sub 2} and H{sub 2}S may be modeled by a first order rate expression. The rate constant at 30{degree}C was found to be 0.243 h{sup {minus}1}. The growth of C. thiosulfatophilum may be modeled in terms of incoming light intensity using a Monod equation: {mu} = {sub 351} + I{sub o}/{sup 0.152}I{sub o}. Comparisons of the growth of R. rubrum and C. thiosulfatophilum shows that the specific growth rate of C. thiosulfatophilum is much higher at a given light intensity.

  5. Gas-Liquid Mass Transfer Characteristics in a Gas-Liquid-Solid Bubble Column under Elevated Pressure and Temperature

    Institute of Scientific and Technical Information of China (English)

    Haibo Jin; Suohe Yang; Guangxiang He; Delin Liu; Zemin Tong; Jianhua Zhu

    2014-01-01

    abstract The volumetric mass transfer coefficient kLa of gases (H2, CO, CO2) and mass transfer coefficient kL on liquid par-affin side were studied using the dynamic absorption method in slurry bubble column reactors under elevated temperature and elevated pressure. Meanwhile, gas-holdup and gas-liquid interfacial area a were obtained. The effects of temperature, pressure, superficial gas velocity and solid concentration on the mass transfer coeffi-cient were discussed. Experimental results show that the gas-liquid volumetric mass transfer coefficient kLa and interfacial area a increased with the increase of pressure, temperature, and superficial gas velocity, and decreased with the slurry concentration. The mass transfer coefficient kL increased with increasing superficial gas velocity and temperature and decreased with higher slurry concentration, while it changed slightly with pressure. Ac-cording to analysis of experimental data, an empirical correlation is obtained to calculate the values of kLa for H2 (CO, CO2) in the gas-paraffin-quartz system in a bubble column under elevated temperature and elevated pressure.

  6. Heat Transfer Enhancement by Fluidized Solid Particles in Gas Carrying Evaporation

    Institute of Scientific and Technical Information of China (English)

    于志家; 孙成新; 孙相彧; 刘展红

    2001-01-01

    Heat transfer characteristics are studied for gas carrying evaporation with fluidized solid particles in a vertical rectangular conduit. Experimental results show that heat transfer of gas carrying evaporation is enhanced and the superheat of liquid in contact with heating surface lowers remarkably by introducing solid particles. Nucleate boiling on the heating surface is suppressed to a considerable degree. The mechanism of heat transfer enhancement by fluidized solid particles is analyzed with the consideration of collisions of solid particles with the boiling vapor bubbles.

  7. An investigation of condensation heat transfer in a closed tube containing a soluble noncondensable gas

    Science.gov (United States)

    Saaski, E. W.; Hanson, R. J.

    1976-01-01

    A more exact one-dimensional condensation heat transfer model for insoluble gases was developed and compared with experimental data. Modifications to this model to accommodate soluble gas behavior were also accomplished, and the effects on gas front behavior demonstrated. Analytical models for condensation heat transfer are documented, and an optical method used for measuring gas concentration profiles is outlined. Experimental data is then presented and interpreted.

  8. Studies on the Influence of Third Component on Gas-Liquid Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of the third component on gas-liquid mass transfer was studied by use of laser holographic interferometry. Four surfactants were added respectively and experimental results show that the microamount of surfactants can change obviously the concentration near the interface on bubble mass transfer process, which indicated that the third component has a significant effect on the bubble mass transfer process.

  9. DMS gas transfer coefficients from algal blooms in the Southern Ocean

    Directory of Open Access Journals (Sweden)

    T. G. Bell

    2014-11-01

    Full Text Available Air/sea dimethylsulfide (DMS fluxes and bulk air/sea gradients were measured over the Southern Ocean in February/March 2012 during the Surface Ocean Aerosol Production (SOAP study. The cruise encountered three distinct phytoplankton bloom regions, consisting of two blooms with moderate DMS levels, and a high biomass, dinoflagellate-dominated bloom with high seawater DMS levels (>15 nM. Gas transfer coefficients were considerably scattered at wind speeds above 5 m s−1. Bin averaging the data resulted in a linear relationship between wind speed and mean gas transfer velocity consistent with that previously observed. However, the wind speed-binned gas transfer data distribution at all wind speeds is positively skewed. The flux and seawater DMS distributions were also positively skewed, which suggests that eddy covariance-derived gas transfer velocities are consistently influenced by additional, log-normal noise. A~flux footprint analysis was conducted during a transect into the prevailing wind and through elevated DMS levels in the dinoflagellate bloom. Accounting for the temporal/spatial separation between flux and seawater concentration significantly reduces the scatter in computed transfer velocity. The SOAP gas transfer velocity data shows no obvious modification of the gas transfer-wind speed relationship by biological activity or waves. This study highlights the challenges associated with eddy covariance gas transfer measurements in biologically active and heterogeneous bloom environments.

  10. Fast ethylamine gas sensing based on intermolecular charge-transfer complexation

    Institute of Scientific and Technical Information of China (English)

    Eun Mi Lee; Seon Young Gwon; Young A Son; Sung Hoon Kim

    2012-01-01

    We have investigated the fast ethylamine gas sensing of 2-chloro-3,5-dinitrobenzotrifluoride (CDBF) loaded poly(acrylonitrile)nanofiber based on an intermolecular charge-transfer complexation.Reversible response and recovery were achieved using alternating gas exposure.This system shows a fast ethylamine gas sensing within 0.4 s.

  11. Fundamental mechanisms that influence the estimate of heat transfer to gas turbine blades

    Science.gov (United States)

    Graham, R. W.

    1979-01-01

    Estimates of the heat transfer from the gas to stationary (vanes) or rotating blades poses a major uncertainty due to the complexity of the heat transfer processes. The gas flow through these blade rows is three dimensional with complex secondary viscous flow patterns that interact with the endwalls and blade surfaces. In addition, upstream disturbances, stagnation flow, curvature effects, and flow acceleration complicate the thermal transport mechanisms in the boundary layers. Some of these fundamental heat transfer effects are discussed. The chief purpose of the discussion is to acquaint those in the heat transfer community, not directly involved in gas turbines, of the seriousness of the problem and to recommend some basic research that would improve the capability for predicting gas-side heat transfer on turbine blades and vanes.

  12. Dissolved gas dynamics in wetland soils: Root-mediated gas transfer kinetics determined via push-pull tracer tests

    Science.gov (United States)

    Reid, Matthew C.; Pal, David S.; Jaffé, Peter R.

    2015-09-01

    Gas transfer processes are fundamental to the biogeochemical and water quality functions of wetlands, yet there is limited knowledge of the rates and pathways of soil-atmosphere exchange for gases other than oxygen and methane (CH4). In this study, we use a novel push-pull technique with sulfur hexafluoride (SF6) and helium (He) as dissolved gas tracers to quantify the kinetics of root-mediated gas transfer, which is a critical efflux pathway for gases from wetland soils. This tracer approach disentangles the effects of physical transport from simultaneous reaction in saturated, vegetated wetland soils. We measured significant seasonal variation in first-order gas exchange rate constants, with smaller spatial variations between different soil depths and vegetation zones in a New Jersey tidal marsh. Gas transfer rates for most biogeochemical trace gases are expected to be bracketed by the rate constants for SF6 and He, which ranged from ˜10-2 to 2 × 10-1 h-1 at our site. A modified Damköhler number analysis is used to evaluate the balance between biochemical reaction and root-driven gas exchange in governing the fate of environmental trace gases in rooted, anaerobic soils. This approach confirmed the importance of plant gas transport for CH4, and showed that root-driven transport may affect nitrous oxide (N2O) balances in settings where N2O reduction rates are slow.

  13. Heat and Mass Transfer Processes in Scrubber of Flue Gas Heat Recovery Device

    OpenAIRE

    Veidenbergs, I; Blumberga, D; Vīgants, E; Kozuhars, G

    2010-01-01

    The paper deals with the heat and mass transfer process research in a flue gas heat recovery device, where complicated cooling, evaporation and condensation processes are taking place simultaneously. The analogy between heat and mass transfer is used during the process of analysis. In order to prepare a detailed process analysis based on heat and mass process descriptive equations, as well as the correlation for wet gas parameter calculation, software in the Microsoft Office Excel environment...

  14. Gas hydrate fast nucleation from melting ice and quiescent growth along vertical heat transfer tube

    Institute of Scientific and Technical Information of China (English)

    XIE; Yingming; GUO; Kaihua; LIANG; Deqing; FAN; Shuanshi

    2005-01-01

    During the observation of HCFC141b gas hydrate growth processes outside a vertical heat transfer tube, two exciting phenomena were found: fast nucleation of gas hydrate from melting ice, and the spontaneous permeation of water into the guest phases along the surface of heat transfer tube to form gas hydrate continuously. These two phenomena were explained with Zhou & Sloan's hypothesis and the theory of surface free energy respectively, and a novel method of gas hydrate formation was presented--gas hydrate fast nucleation from melting ice and quiescent growth along heat transfer tube. There is no mechanic stirring in this method, the formed gas hydrates are compact, the ratio of unreacted interstitial water is little, which overcome the drawback of high energy cost and high ratio of unreacted interstitial water among the formed gas hydrates in the system with mechanic stirring. This finding will benefit the gas hydrate application technologies such as natural gas storage technology or cool storage technology with gas hydrate.

  15. Mass transfer and hydrodynamics in stirred gas-liquid-liquid contactors

    NARCIS (Netherlands)

    Cents, Antonius Harold Gerrit

    2003-01-01

    It can be concluded from the research study described in this thesis that the mechanism of mass transfer in gas-liquid-liquid systems is still not completely clear. In this work mass transfer experiments were carried out with five different organic dispersed liquids, toluene, 1-octanol, n-heptane, n

  16. The FCC Flue Gas SOx Transfer Additive RFS Developed by RIPP

    Institute of Scientific and Technical Information of China (English)

    Chen Beiyan; Jiang Wenbin; Song Haitao; Shen Ningyuan; Tian Huiping; He Mingyuan

    2007-01-01

    The present paper introduces the development of FCC flue gas SOx transfer additives by RIPP with a brief discussion of SOx transfer mechanism. The second-generation SOx transfer additives of the RFS series are RIPP's proprietary additives with significantly improved performances. The results of commercial tests indicate that the RFS additive can effectively control SOx emission of the FCC regenerator while maintaining product yields and product quality when the additive is used in a proper concentration range.

  17. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1: Physical mass transfer processes. A specific application: mass transfer in highly viscous liquids

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Smolders, C.A.; Swaaij, van W.P.M.

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  18. Gas-Liquid Mass Transfer in a Slurry Bubble Column Reactor under High Temperature and

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The gas-liquid mass transfer of H2 and CO in a high temperature and high-pressure three-phase slurry bubble column reactor is studied. The gas-liquid volumetric mass transfer coefficients κLα are obtained by measuring the dissolution rate of H2 and CO. The influences of the main operation conditions, such as temperature, pressure, superficial gas velocity and solid concentration, are studied systematically. Two empirical correlations are proposed to predict κLα values for H2 and CO in liquid paraffin/solid particles slurry bubble column reactors.

  19. Enhanced convective and film boiling heat transfer by surface gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.; Greene, G.A. (Brookhaven National Lab., Upton, NY (United States)); Irvine, T.F., Jr. (State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering)

    1992-04-01

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured (0 to 8.5 cm/s), the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  20. Enhanced convective and film boiling heat transfer by surface gas injection

    Energy Technology Data Exchange (ETDEWEB)

    Duignan, M.R.; Greene, G.A. [Brookhaven National Lab., Upton, NY (United States); Irvine, T.F., Jr. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Mechanical Engineering

    1992-04-01

    Heat transfer measurements were made for stable film boiling of water over a horizontal, flat stainless steel plate from the minimum film boiling point temperature, T{sub SURFACE} {approximately}500K, to T{sub SURFACE} {approximately}950K. The pressure at the plate was approximately 1 atmosphere and the temperature of the water pool was maintained at saturation. The data were compared to the Berenson film-boiling model, which was developed for minimum film-boiling-point conditions. The model accurately represented the data near the minimum film-boiling point and at the highest temperatures measured, as long it was corrected for the heat transferred by radiation. On the average, the experimental data lay within {plus_minus}7% of the model. Measurements of heat transfer were made without film boiling for nitrogen jetting into an overlying pool of water from nine 1-mm- diameter holes, drilled in the heat transfer plate. The heat flux was maintained constant at approximately 26.4 kW/m{sup 2}. For water-pool heights of less than 6cm the heat transfer coefficient deceased linearly with a decrease in heights. Above 6cm the heat transfer coefficient was unaffected. For the entire range of gas velocities measured [0 to 8.5 cm/s], the magnitude of the magnitude of the heat transfer coefficient only changed by approximately 20%. The heat transfer data bound the Konsetov model for turbulent pool heat transfer which was developed for vertical heat transfer surfaces. This agreement suggests that surface orientation may not be important when the gas jets do not locally affect the surface heat transfer. Finally, a database was developed for heat transfer from the plate with both film boiling and gas jetting occurring simultaneously, in a pool of water maintained at its saturation temperature. The effect of passing nitrogen through established film boiling is to increase the heat transfer from that surface. 60 refs.

  1. OGO-6 gas-surface energy transfer experiment

    Science.gov (United States)

    Mckeown, D.; Dummer, R. S.; Bowyer, J. M., Jr.; Corbin, W. E., Jr.

    1973-01-01

    The kinetic energy flux of the upper atmosphere was analyzed using OGO-6 data. Energy transfer between 10 microwatts/sq cm and 0.1 W/sq cm was measured by short-term frequency changes of temperature-sensitive quartz crystals used in the energy transfer probe. The condition of the surfaces was continuously monitored by a quartz crystal microbalance to determine the effect surface contamination had on energy accommodation. Results are given on the computer analysis and laboratory tests performed to optimize the operation of the energy transfer probe. Data are also given on the bombardment of OGO-6 surfaces by high energy particles. The thermoelectrically-cooled quartz crystal microbalance is described in terms of its development and applications.

  2. Optimizing Geothermal Drilling: Oil and Gas Technology Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Denninger, Kate; Eustes, Alfred; Visser, Charles; Baker, Walt; Bolton, Dan; Bell, Jason; Bell, Sean; Jacobs, Amelia; Nagandran, Uneshddarann; Tilley, Mitch; Quick, Ralph

    2015-09-02

    There is a significant amount of financial risk associated with geothermal drilling. This study of drilling operations seeks opportunities to improve upon current practices and technologies. The scope of this study included analyzing 21 geothermal wells and 21 oil and gas wells. The goal was to determine a 'Perfect Well' using historical data to compare the best oil and gas well to the best geothermal well. Unfortunately, limitations encountered in the study included missing data (bit records, mud information, etc.) and poor data collection practices An online software database was used to format drilling data to IADC coded daily drilling reports and generate figures for analysis. Six major issues have been found in geothermal drilling operations. These problems include lost circulation, rig/ equipment selection, cementing, penetration rate, drilling program, and time management. As a result of these issues, geothermal drilling averaged 56.4 days longer than drilling comparable oil and gas wells in the wells in this study. Roughly $13.9 million was spent on non-productive time in the 21 geothermal wells, compared with only $1.3 million in the oil and gas wells, assuming a cost of $50,000 per day. Comparable events such as drilling the same sized hole, tripping in/out, cementing, and running the same size casing took substantially less time in the oil and gas wells. Geothermal wells were drilled using older and/or less advanced technology to depths less than 10,000 feet, while oil and gas wells reached 12,500 feet faster with purpose built rigs. A new approach is now underway that will optimize drilling programs throughout the drilling industry using Mechanical Specific Energy (MSE) as a tool to realize efficient drilling processes. Potential improvements for current geothermal operations are: the use of electronic records, real time services, and official glossary terms to describe rig operations, and advanced drilling rigs/technology.

  3. Aspects of mass transfer in gas-liquid oxidation reactions

    NARCIS (Netherlands)

    Hoorn, Johannes Adriaan Aris

    2005-01-01

    Chemical reactors in which reactants are present in both gas and liquid occur frequently in industry. The study of these type of reactors is quite a challenge in many aspects. Clever design and optimisation increase the profit of the chemical plant, improve safety and reduce the impact on the enviro

  4. CONJUGATE MODEL FOR HEAT AND MASS TRANSFER OF POROUS WALL IN THE HIGH TEMPERATURE GAS FLOW

    Institute of Scientific and Technical Information of China (English)

    A.F. Polyakov; D.L.Reviznikov; 沈青; 魏叔如

    2001-01-01

    Heat and mass transfer of a porous permeable wall in a high temperature gas dynamical flow is considered. Numerical simulation is conducted on the ground of the conjugate mathematical model which includes filtration and heat transfer equations in a porous body and boundary layer equations on its surface. Such an approach enables one to take into account complex interaction between heat and mass transfer in the gasdynamical flow and in the structure subjected to this flow.The main attention is given to the impact of the intraporous heat transfer intensity on the transpiration cooling efficiency.

  5. Thermal Analysis of the Divertor Primary Heat Transfer System Piping During the Gas Baking Process

    Energy Technology Data Exchange (ETDEWEB)

    Yoder Jr, Graydon L [ORNL; Harvey, Karen [ORNL; Ferrada, Juan J [ORNL

    2011-02-01

    A preliminary analysis has been performed examining the temperature distribution in the Divertor Primary Heat Transfer System (PHTS) piping and the divertor itself during the gas baking process. During gas baking, it is required that the divertor reach a temperature of 350 C. Thermal losses in the piping and from the divertor itself require that the gas supply temperature be maintained above that temperature in order to ensure that all of the divertor components reach the required temperature. The analysis described in this report was conducted in order to estimate the required supply temperature from the gas heater.

  6. Optimizing Geothermal Drilling: Oil and Gas Technology Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Tilley, Mitch; Eustes, Alfred; Visser, Charles; Baker, Walt; Bolton, Dan; Bell, Jason; Nagandran, Uneshddarann; Quick, Ralph

    2015-01-26

    There is a significant amount of financial risk associated with geothermal drilling; however, there are opportunities to improve upon current practices and technologies used. The scope of this drilling operational study included 21 geothermal wells and 21 oil and gas wells. The goal was to determine a 'perfect well' using historical data to compare the best oil and gas well to the best geothermal well. Unfortunately, limitations encountered in the study included missing data (bit records, mud information, etc.), poor data collection, and difficult to ascertain handwriting. An online software database was used to format drilling data to IADC coded daily drilling reports and generate analysis figures. Six major issues have been found in geothermal drilling operations. These problems include lost circulation, rig/equipment selection, cementing, penetration rate, drilling program, and time management. As a result of these issues, geothermal drilling averages 56.4 days longer than drilling comparable oil and gas wells in the wells in this study. Roughly $13.9 million would be lost due to non-productive time in the 21 geothermal wells and only $1.3 million in the oil and gas wells, assuming a cost of $50,000 per day. Comparable events such as drilling the same sized hole, tripping in/out, cementing, and running the same size casing took substantially less time in the oil and gas wells. Geothermal wells were drilled using older and/or less advanced technology to depths less than 10,000 feet, while oil and gas wells reached 12,500 feet faster with purpose built rigs. A new approach is now underway that will optimize drilling programs throughout the drilling industry. It is the use of Mechanical Specific Energy (MSE) as a tool to realize efficient drilling processes. However, a work-flow must also be established in order for there to be an efficient drilling program. Potential improvements for current geothermal operations are: the use of electronic records, real

  7. Effect of particle loading on heat transfer enhancement in a gas-solid suspension cross flow

    Institute of Scientific and Technical Information of China (English)

    周劲松; 骆仲泱; 高翔; 倪明江; 岑可法

    2002-01-01

    Heat transfer between gas-solid multiphase flow and tubes occurs in many industry processes, such as circulating fluidized bed process, pneumatic conveying process, chemical process, drying process, etc. (This paper focuses on the influence of the presence of particles on the heat transfer between a tube and gas-solid sus-pension. The presence of particles causes positive enhancement of heat transfer in the case of high solid loading ratio, but heat transfer reduction has been found for in the case of very low soliding ratio (Ms of less than 0.05 kg/kg). A usefial correlation ineorpomting solid lolling ratio, particle size and flow Reytmlds number was derived from experimental data. In addition, the κ-ε two-equation model and the Fluctuation-Spectrum-Random-Trajectory Model (FSRT Model) are used to simulate the flow field and heat transit of the gas-phase and the solid-phase, respectively. Through coupling of the two phases the model can predict the local and total heat transfer characteristics of tube in gas-solid cross flow. For the total heat transfer enhancement due to particles loading the model predictions agreed well wih experimental data.

  8. Connection Between Liquid Distribution and Gas-Liquid Mass Transfer in Monolithic Bed

    Institute of Scientific and Technical Information of China (English)

    许闽; 刘辉; 李成岳; 周媛; 季生福

    2011-01-01

    With a particular focus on the connection between liquid flow distribution and gas-liquid mass transfer in monolithic beds in the Taylor flow regime, hydrodynamic and gas-liquid mass transfer experiments were carriedout in a column with a monolithic bed of cell density of 50 cpsi with trio different distributors (nozzle and packed bed distributors). Liquid saturation in individual channels was measured by using self-made micro-conductivity probes. A mal-distribution factor was used to evaluate uniform degree of phase distribution in monoliths. Overall bed pressure drop and mass transfer coefficients were measured. For liquid flow distribution and gas-liquid masstransfer, it is found that the superficial liquid velocity is a crucial factor and the packed bed distributor is better than the nozzle distributor. A semi-theoretical analysis using single channel models shows that the packed bed distributor always yields shorter and uniformly distributed liquid slugs compared to the nozzle distributor, which in turn ensures a better mass transfer performance. A bed scale mass transfer model is proposed by employing the single channel models in individual channels and incorporating effects of non-uniform liquid distribution along the bedcross-section. The model predicts the overall gas-liquid mass transfer coefficient wig a relative error within +30%.

  9. A conjugate heat transfer procedure for gas turbine blades.

    Science.gov (United States)

    Croce, G

    2001-05-01

    A conjugate heat transfer procedure, allowing for the use of different solvers on the solid and fluid domain(s), is presented. Information exchange between solid and fluid solution is limited to boundary condition values, and this exchange is carried out at any pseudo-time step. Global convergence rate of the procedure is, thus, of the same order of magnitude of stand-alone computations.

  10. Design of Solid-Gas Interfaces for Enhanced Thermal Transfer

    Science.gov (United States)

    2015-09-28

    components used in the Air Force hardware. 15. SUBJECT TERMS energy and momentum exchange at solid liquid -interface chemical surface modification and...increased energy exchange efficiency as the gas atom mass is better matching solid atom mass. When the trapping -desorption dynamics dominates for...adsorption in single-walled carbon nanotube bundles, Int. J. Quant. Chem. 108, (2008) 1714. [17] P. S. Cheung, J. G. Powles, The properties of liquid

  11. Effect of particle loading on heat transfer enhancement in a gas-solid suspension cross flow

    Institute of Scientific and Technical Information of China (English)

    周劲松; 骆仲泱; 高翔; 倪明江; 岑可法

    2002-01-01

    Heat transfer between gas-solid multiphase flow and tubes occurs in m a ny industry processes, such as circulating fluidized bed process, pneumatic conv eying process, chemical process, drying process, etc. This paper focuses on the influence of the presence of particles on the heat transfer between a tube and g as-solid suspension. The presence of particles causes positive enhancement of h e at transfer in the case of high solid loading ratio, but heat transfer reduction has been found for in the case of very low solid loading ratio (Ms of les s than 0.05 kg/kg). A useful correlation incorporating solid loading ratio, particle s ize and flow Reynolds number was derived from experimental data. In addition, th e k-ε two-equation model and the Fluctuation-Spectrum- Random-Trajecto ry Model ( FSRT Model) are used to simulate the flow field and heat transfer of the gas-ph a se and the solid-phase, respectively. Through coupling of the two phases the mo d el can predict the local and total heat transfer characteristics of tube in gas - solid cross flow. For the total heat transfer enhancement due to particles loadi ng the model predictions agreed well with experimental data.

  12. The boomerang area: An example of oil and gas fields related to a transfer zone development

    Energy Technology Data Exchange (ETDEWEB)

    Specht, M.; Colletta, B.; Letouzey, J. (Institut Francais de petrole, Ruiel-Malmaison (France)); Baby, P. (ORSTOM, Santa Cruz (Bolivia)); Oller, J.; Montemuro, G. (YPFB, Santa Cruz (Bolivia)); Guillier, B. (IFEA, Santa Cruz (Bolivia))

    1993-02-01

    We present results of a study realized from petroleum data of Yacimientos Petroliferos Fiscales Bolivianos of the most important transfer zone of the Bolivian Andean belt: the Santa Cruz transfer zone. Frontal part of the Bolivian Andean belt consists of a thick series (6 to 8 km) of paleozoic to cenozoic sedimentary rocks thrusted eastwards on a sole thrust located in paleozoic series. The frontal part of the belt, globally N-S oriented, undergoes an important deviation East of Santa Cruz with a left lateral offset of 100 Km. Taking into account the E-W shortening direction, this transfer zone can be interpreted as a lateral ramp. The Santa Cruz transfer zone coincide with a set of small oil and gas fields whereas frontal structures lack hydrocarbon occurrences. We are then faced with a two-fold problem: (1) what is the origin of the transfer zone (2) why are the oil and gas concentrated in the transfer zone Our synthesis shows that the transfer zone is superimposed on the limit of a detached Paleozoic basin whose border direction is oblique to the regional shortening direction. We then interpret the oil and gas formation in two steps: (1) source rock maturation and hydrocarbon migration towards the top of the Paleozoic sedimentary wedge before Andean deformation. (2) hydrocarbon dismigration towards anticlinal structures developed during the lateral ramp propagation. In order to test our interpretation we performed a set of analog model experiments whose 3D visualization was analyzed by computerized X-ray tomography.

  13. Gas transfer model to design a ventilator for neonatal total liquid ventilation.

    Science.gov (United States)

    Bonfanti, Mirko; Cammi, Antonio; Bagnoli, Paola

    2015-12-01

    The study was aimed to optimize the gas transfer in an innovative ventilator for neonatal Total Liquid Ventilation (TLV) that integrates the pumping and oxygenation functions in a non-volumetric pulsatile device made of parallel flat silicone membranes. A computational approach was adopted to evaluate oxygen (O2) and carbon dioxide (CO2) exchanges between the liquid perfluorocarbon (PFC) and the oxygenating gas, as a function of the geometrical parameter of the device. A 2D semi-empirical model was implemented to this purpose using Comsol Multiphysics to study both the fluid dynamics and the gas exchange in the ventilator. Experimental gas exchanges measured with a preliminary prototype were compared to the simulation outcomes to prove the model reliability. Different device configurations were modeled to identify the optimal design able to guarantee the desired gas transfer. Good agreement between experimental and simulation outcomes was obtained, validating the model. The optimal configuration, able to achieve the desired gas exchange (ΔpCO2 = 16.5 mmHg and ΔpO2 = 69 mmHg), is a device comprising 40 modules, 300 mm in length (total exchange area = 2.28 m(2)). With this configuration gas transfer performance is satisfactory for all the simulated settings, proving good adaptability of the device.

  14. Characterization of gas transfer and mixing in a bubble column equipped with a rubber membrane diffuser

    Science.gov (United States)

    Poulsen; Iversen

    1998-06-20

    Gas transfer and mixing were characterized in a 32-L bubble column reactor equipped with a commercially available rubber membrane diffuser. The performance of the membrane diffuser indicates that the slits in the membrane are best described as holes with elastic lids, acting as valves cutting off bubbles from the gas stream. The membrane diffuser thus functions as a one-way valve preventing backflow of liquid. Our design of the bottom plate of the reactor enabled us to optimize the aeration by changing the tension of the membrane. We thereby achieved mass transfer coefficients higher than those previously reported in bubble columns. A strong dependence of mass transfer on gas holdup and bubble size was indicated by estimates based on these two variables. The microalga, Rhodomonas sp. , sensitive to chemical and physical stress, was maintained for 8 months in continuous culture with a productivity identical to cultures grown in stirred tank reactors. Copyright 1998 John Wiley & Sons, Inc.

  15. Mass Transfer Enhancement of Gas Absorption by Adding the Dispersed Organic Phases

    Institute of Scientific and Technical Information of China (English)

    张志刚; 许天行; 李文秀; 纪智玲; 许光荣

    2011-01-01

    Mass transfer enhancement of gas absorption by adding a dispersed organic phase has been studied in this work. Various dispersed organic phases (heptanol, octanol, isoamyl alcohol, heptane, octane, and isooctane) were tested respectively in the experiment. According to the theoretical model and experimental data, the overall volumetric mass transfer coefficient and enhancement factor were obtained under different dispersed organic phase volume fraction and stirring speed. The experimental results indicate that gas-liquid mass transfer is enhanced at different level by adding a dispersed organic phase. The best performance of enhancement were achieved with the dispersed organic phase volumetric fraction of 5% and under an intermediate stirring speed of 670 r·min^-1. Among the organic phases tested in the experiment, alcohols show better performance, which gave 20% higher enhance-ment of overall volumetric mass transfer coefficient than adding alkanes.

  16. Experience Transfer in Norwegian Oil and Gas Industry: Approaches and Organizational Mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Aase, Karina

    1997-07-01

    The core aim of the study is to explore the concept of experience transfer in oil and gas industry, and how an oil company approaches this concept. The thesis consists of five papers which are combined in a general description entitled 'Experience transfer in Norwegian oil and gas industry: approaches and organizational mechanisms'. The first paper describes how organizational members perceive experience transfer, and then specifies the many organizational and structural barriers that have to be overcome to achieve efficient experience transfer. The second paper elaborates and assesses the organizational means an oil company implements to address experience transfer. The third paper describes a process of improving and using requirement and procedure handbooks for experience transfer. The fourth paper explores in more detail how the use of information technology influences experience transfer. And the fifth paper compares organizational members' perceptions of experience transfer means in an oil company and an engineering company involved in offshore development projects. Some of the papers are based upon the same data material. Therefore there are reiterations in parts of the contents, especially in the methodological sections.

  17. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Błaszczuk Artur

    2015-09-01

    Full Text Available This paper focuses on assessment of the effect of flue gas recirculation (FGR on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  18. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    Science.gov (United States)

    Błaszczuk, Artur

    2015-09-01

    This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  19. Energy transfer process in gas models of Lennard-Jones interactions

    CERN Document Server

    Yang, Jinghua; Wang, Jiao; Zhao, Hong

    2011-01-01

    We perform simulations to investigate how the energy carried by a molecule transfers to others in an equilibrium gas model. For this purpose we consider a microcanonical ensemble of equilibrium gas systems, each of them contains a tagged molecule located at the same position initially. The ensuing transfer process of the energy initially carried by the tagged molecule is then exposed in terms of the ensemble-averaged energy density distribution. In both a 2D and a 3D gas model with Lennard-Jones interactions at room temperature, it is found that the energy carried by a molecule propagates in the gas ballistically, in clear contrast with the Gaussian diffusion widely assumed in previous studies. A possible scheme of experimental study of this issue is also proposed

  20. High-precision gas gain and energy transfer measurements in Ar–CO2 mixtures

    CERN Document Server

    Şahin, Özkan; Veenhof, Rob

    2014-01-01

    Ar–CO2 is a Penning mixture since a fraction of the energy stored in Ar 3p53d3p53d and higher excited states can be transferred to ionize CO2 molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO2 mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO2 at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×105.

  1. High-precision gas gain and energy transfer measurements in Ar–CO{sub 2} mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Şahin, Özkan, E-mail: osahin@uludag.edu.tr [Department of Physics, Uludağ University, 16059 Bursa (Turkey); Kowalski, Tadeusz Z. [Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, Kraków (Poland); Veenhof, Rob [Department of Physics, Uludağ University, 16059 Bursa (Turkey); RD51 collaboration, CERN, Genève (Switzerland)

    2014-12-21

    Ar–CO{sub 2} is a Penning mixture since a fraction of the energy stored in Ar 3p{sup 5}3d and higher excited states can be transferred to ionize CO{sub 2} molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar–CO{sub 2} mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1–50% CO{sub 2} at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5×10{sup 5}.

  2. Convective heat transfer for incompressible laminar gas flow in micropassage with constant wall temperature

    Institute of Scientific and Technical Information of China (English)

    安刚; 李俊明; 王补宣

    2001-01-01

    Theoretical investigations have been performed on the convective heat transfer for incompressible laminar flow of gases through microtube and parallel-plates micropassages with constant wall temperature. Considering the change in thermal conductivity and viscosity of gas in wall adjacent region from the kinetic theory, mathematical models are built for both of the micropassages. The dimensionless temperature distribution and the corresponding heat transfer characteristics are simulated numerically, and the results discussed briefly.

  3. Effect of liquid distribution on gas-water phase mass transfer in an unsaturated sand during infiltration

    Science.gov (United States)

    Imhoff, Paul T.; Jaffé, Peter R.

    1994-09-01

    Gas-water phase mass transfer was examined in a homogeneous sand with both the gas and water phase mobile: water was infiltrated from the top of the sand column while benzene-laden air flowed upward from the bottom. Mass-transfer limitations for this situation may be important for applications of bioventing, where water and nutrients are added at the ground surface simultaneously with induced air movement to carry oxygen and volatile organics to microbial populations. Gas- and water-phase samples indicate that gas-water phase mass transfer was sufficiently fast that equilibrium between gas and water phases was achieved at all sampling locations within the porous medium. Lower-bound estimates for the gas-water mass-transfer rate coefficient show that mass transfer was at least 10-40 times larger than predictions made from an empirical model developed for gas-water phase mass transfer in an identical porous medium. A water-phase tracer test demonstrates that water flow was much more uniform in this study than in those earlier experiments, which is a likely explanation for the differing rates of gas-water phase mass transfer. It is hypothesized that the liquid distribution in previous laboratory experiments was less uniform because of preferential flow paths due to wetting front instabilities. Gas-water phase mass-transfer rate coefficients reported in this investigation are for an ideal situation of uniform water infiltration: mass-transfer rates in field soils are expected to be significantly smaller.

  4. Acoustic Transfer Functions Derived from Finite Element Modeling for Thermoacoustic Stability Predictions of Gas Turbine Engines

    OpenAIRE

    Black, Paul Randall

    2007-01-01

    Acoustic Transfer Functions Derived from Finite Element Modeling for Thermoacoustic Stability Predictions of Gas Turbine Engines Design and prediction of thermoacoustic instabilities is a major challenge in aerospace propulsion and the operation of power generating gas turbine engines. This is a complex problem in which multiple physical systems couple together. Traditionally, thermoacoustic models can be reduced to dominant physics which depend only on flame dynamics and acoustics. Th...

  5. Gas stream in Algol. [mass transfer in binary star systems

    Science.gov (United States)

    Cugier, H.; Chen, K.-Y.

    1977-01-01

    Additional absorption features in the red wings of the Mg II resonance lines near 2800 A are found in observations of Algol made from the Copernicus satellite. The absorption features were clearly seen only during a part of the primary eclipse, in the phase interval 0.90-0.03. The observations are interpreted as being produced by a stream of matter flowing from Algol B in the direction of Algol A. The measured Doppler shifts of the features give the value of 150 km/s as the characteristic velocity of matter in the stream. The mass transfer connected with the stream is estimated to be of the order of 10 to the -13th power solar mass per year.

  6. Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip

    Science.gov (United States)

    Azad, Gm S.; Han, Je-Chin; Teng, Shuye; Boyle, Robert J.

    2000-01-01

    Heat transfer coefficient and static pressure distributions are experimentally investigated on a gas turbine blade tip in a five-bladed stationary linear cascade. The blade is a 2-dimensional model of a first stage gas turbine rotor blade with a blade tip profile of a GE-E(sup 3) aircraft gas turbine engine rotor blade. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial chord of 1.1 x 10(exp 6). The middle 3-blade has a variable tip gap clearance. All measurements are made at three different tip gap clearances of about 1%, 1.5%, and 2.5% of the blade span. Heat transfer measurements are also made at two different turbulence intensity levels of 6.1 % and 9.7% at the cascade inlet. Static pressure measurements are made in the mid-span and the near-tip regions as well as on the shroud surface, opposite the blade tip surface. Detailed heat transfer coefficient distributions on the plane tip surface are measured using a transient liquid crystal technique. Results show various regions of high and low heat transfer coefficient on the tip surface. Tip clearance has a significant influence on local tip beat transfer coefficient distribution. Heat transfer coefficient also increases about 15-20% along the leakage flow path at higher turbulence intensity level of 9.7% over 6.1 %.

  7. Microporous hollow fibre membrane modules as gas-liquid contactors. Part 1. Physical mass transfer processes : A specific application

    NARCIS (Netherlands)

    Kreulen, H.; Versteeg, G.F.; Swaaij, W.P.M. van

    1993-01-01

    Gas-liquid mass transfer has been studied in a membrane module with non-wetted microporous fibres in the laminar flow regime. This new type of gas/liquid contactor can be operated stabily over a large range of gas and liquid flows because gas and liquid phase do not influence each other directly. Th

  8. Study of 3-D Numerical Simulation for Gas Transfer in the Goaf of the Coal Mining

    Institute of Scientific and Technical Information of China (English)

    WU Zheng-yan; JIANG Shu-guang; HE Xin-jian; WANG Lan-yun; LIN Bai-quan

    2007-01-01

    In order to simulate field distribution rules, mathematical models for 3-D air flows and gas transfer in the goaf of the coal mining are established, based on theories of permeability and dynamic dispersion through porous media. A gas dispersion equation in a 3-D field is calculated by use of numerical method on a weighted upstream multi-element balance. Based on data of an example with a U type ventilation mode, surface charts of air pressure distribution and gas concentration are drawn by Graphtool software. Finally, a comparison between actually measured results in the model test and the numerical simulation results is made to proves the numerical implementation feasible.

  9. Convective heat transfer for incompressible laminar gas flow in micropassage with constant wall temperature

    Institute of Scientific and Technical Information of China (English)

    An; Gang; (

    2001-01-01

    [1]Tuckermann, D. B., Pease, R. F., Optimized convective cooling using micromachined structure, J. Electro-Chemical Society, 1982, 129(3): 98c.[2]Wu Peiyi, Little, W. A., Measurement of friction factor for the flow of gases in very fine channel used for microminiature Joule-Thomson refrigerators, Cryogenics, 1983, 23(5): 273.[3]Wu Peiyi, Little, W. A., Measurement of the heat transfer characteristics of gas flow in fine channel heat exchangers used for microminiature refrigerators, Cryogenics, 1984, 24(8): 415.[4]Choi, B., Barron, R. F., Warrington, R. O., Fluid flow and heat transfer in microtubes, ASME DSC, 1991, 32: 123.[5]Pfahler, J., Harley, J., Bua, H. et al., Gas and liquid flow in small channel, ASME DSC, 1991, 32: 49.[6]Beskok, A., Karniadakis, G. E., Simulation of slip-flow in complex micro-geometries, ASME DSC, 1992, 40: 355.[7]Mohiuddin, M. G., Li Dongqing, Dale, J. D., Heat transfer and fluid flow in microchannels, Int. J. Heat and Mass Transfer, 1997, 40(13): 3079.[8]Li, J. M., Wang, B. X., Peng, X. F., The wall effect for laminar flow through microtube, in Int. Center for Heat and Mass Transfer (ICHMT) Symposium on Molecular and Microscale Heat Transfer in Material Processing and Other Application Yokohama, Japan, (eds. Tanasawa, I., Nishio, S.), New York: Begell House,1996, 55-65.[9]Li, J. M., Wang, B. X., Peng, X. F., Laminar flow of gas through extremely narrow parallel plates, in Heat Transfer and Technology 1996, Proc. Fourth ISHT (ed. Wang, B. X.), Beijing: Higher Education Press, 1996, 318-322.[10]Li, J. M., Wang, B. X., Peng, X. F., Wall effect of gas laminar heat transfer in microtubes, Journal of Engineering Thermophysics (in Chinese), 1998, 19(5): 596.[11]Li, J. M., Wang, B. X., Peng, X. F., Laminar heat transfer of gas in microchannels between two paralled plates, Journal of Engineering Thermophysics (in Chinese), 1999, 20(2): 194.[12]Tao, W. Q., Numerical Heat Transfer (in Chinese), Xi

  10. Modeling of Aerobrake Ballute Stagnation Point Temperature and Heat Transfer to Inflation Gas

    Science.gov (United States)

    Bahrami, Parviz A.

    2012-01-01

    A trailing Ballute drag device concept for spacecraft aerocapture is considered. A thermal model for calculation of the Ballute membrane temperature and the inflation gas temperature is developed. An algorithm capturing the most salient features of the concept is implemented. In conjunction with the thermal model, trajectory calculations for two candidate missions, Titan Explorer and Neptune Orbiter missions, are used to estimate the stagnation point temperature and the inflation gas temperature. Radiation from both sides of the membrane at the stagnation point and conduction to the inflating gas is included. The results showed that the radiation from the membrane and to a much lesser extent conduction to the inflating gas, are likely to be the controlling heat transfer mechanisms and that the increase in gas temperature due to aerodynamic heating is of secondary importance.

  11. Carbon dioxide stripping in aquaculture -- part II: development of gas transfer models

    Science.gov (United States)

    Colt, John; Watten, Barnaby; Pfeiffer, Tim

    2012-01-01

    The basic mass transfer equation for gases such as oxygen and carbon dioxide can be derived from integration of the driving force equation. Because of the physical characteristics of the gas transfer processes, slightly different models are used for aerators tested under the non steady-state procedures, than for packed columns, or weirs. It is suggested that the standard condition for carbon dioxide should be 20 °C, 1 atm, CCO2=20 mg/kg, and XCO2=0.000285. The selection of the standard condition for carbon dioxide based on a fixed mole fraction ensures that standardized carbon dioxide transfer rates will be comparable even though the value of C*CO2 in the atmosphere is increasing with time. The computation of mass transfer for carbon dioxide is complicated by the impact of water depth and gas phase enrichment on the saturation concentration within the unit, although the importance of either factor depends strongly on the specific type of aerator. For some types of aerators, the most accurate gas phase model remains to be determined for carbon dioxide. The assumption that carbon dioxide can be treated as a non-reactive gas in packed columns may apply for cold acidic waters but not for warm alkaline waters.

  12. Mass transfer in thin films under counter-current gas: experiments and numerical study

    Science.gov (United States)

    Lucquiaud, Mathieu; Lavalle, Gianluca; Schmidt, Patrick; Ausner, Ilja; Wehrli, Marc; O Naraigh, Lennon; Valluri, Prashant

    2016-11-01

    Mass transfer in liquid-gas stratified flows is strongly affected by the waviness of the interface. For reactive flows, the chemical reactions occurring at the liquid-gas interface also influence the mass transfer rate. This is encountered in several technological applications, such as absorption units for carbon capture. We investigate the absorption rate of carbon dioxide in a liquid solution. The experimental set-up consists of a vertical channel where a falling film is sheared by a counter-current gas flow. We measure the absorption occurring at different flow conditions, by changing the liquid solution, the liquid flow rate and the gas composition. With the aim to support the experimental results with numerical simulations, we implement in our level-set flow solver a novel module for mass transfer taking into account a variant of the ghost-fluid formalism. We firstly validate the pure mass transfer case with and without hydrodynamics by comparing the species concentration in the bulk flow to the analytical solution. In a final stage, we analyse the absorption rate in reactive flows, and try to reproduce the experimental results by means of numerical simulations to explore the active role of the waves at the interface.

  13. Gas-transfer analysis. Section H - real gas results via the van der Waals equation of state and virial expansion extension of its limiting Abel-Noble form

    Energy Technology Data Exchange (ETDEWEB)

    Chenoweth, D R

    1983-06-01

    An ideal-gas, quasi-steady, duct-flow model previously formulated for small scale gas-transfer problems is extended to real gases via the van der Waals equation of state as well as general virial expansions. The model is applicable for an arbitrary series of ducting components where each is described empirically by total pressure and total temperature change correlations. The adequacy of the van der Waals model for gas-transfer calculations is verified by comparisons with: (1) real gas PVT data; (2) the magnitudes of the controlling effects; and (3) approximate limiting case solutions with numerical results using more accurate real-gas modeling. 25 figures.

  14. Heat Transfer between an Individual Carbon Nanotube and Gas Environment in a Wide Knudsen Number Regime

    Directory of Open Access Journals (Sweden)

    Hai-Dong Wang

    2013-01-01

    Full Text Available Applications of carbon nanotube (CNT and graphene in thermal management have recently attracted significant attention. However, the lack of efficient prediction formula for heat transfer coefficient between nanomaterials and gas environment limits the further development of this technique. In this work, a kinetic model has been established to predict the heat transfer coefficient of an individual CNT in gas environment. The heat dissipation around the CNT is governed by molecular collisions, and outside the collision layer, the heat conduction is dominant. At nanoscales, the natural convection can be neglected. In order to describe the intermolecular collisions around the CNT quantitatively, a correction factor 1/24 is introduced and agrees well with the experimental observation. The prediction of the present model is in good agreement with our experimental results in free molecular regime. Further, a maximum heat transfer coefficient occurs at a critical diameter of several nanometers, providing guidelines on the practical design of CNT-based heat spreaders.

  15. Fission-gas release at extended burnups: effect of two-dimensional heat transfer

    Energy Technology Data Exchange (ETDEWEB)

    Tayal, M. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada); Yu, S.D. [Ryerson Polytechnic Univ., Toronto, Ontario (Canada); Lau, J.H.K

    2000-09-01

    To better simulate the performance of high-burnup CANDU fuel, a two-dimensional model for heat transfer between the pellet and the sheath has been added to the computer code ELESTRES. The model covers four relative orientations of the pellet and the sheath and their impacts on heat transfer and fission-gas release. The predictions of the code were compared to a database of 27 experimental irradiations involving extended burnups and normal burnups. The calculated values of fission gas release matched the measurements to an average of 94%. Thus, the two-dimensional heat transfer model increases the versatility of the ELESTRES code to better simulate fuels at normal as well as at extended burnups. (author)

  16. Progress towards understanding and predicting convection heat transfer in the turbine gas path

    Science.gov (United States)

    Simoneau, Robert J.; Simon, Frederick F.

    1992-01-01

    A new era is drawing in the ability to predict convection heat transfer in the turbine gas path. We feel that the technical community now has the capability to mount a major assault on this problem, which has eluded significant progress for a long time. We hope to make a case for this bold statement by reviewing the state of the art in three major heat transfer, configuration-specific experiments, whose data have provided the big picture and guided both the fundamental modeling research and the code development. Following that, we review progress and directions in the development of computer codes to predict turbine gas path heat transfer. Finally, we cite examples and make observations on the more recent efforts to do all this work in a simultaneous, interactive, and more synergistic manner. We conclude with an assessment of progress, suggestions for how to use the current state of the art, and recommendations for the future.

  17. Heat Transfer Research of Gas-solid-liquid Three Phase Coupling of EGR Cooler

    Directory of Open Access Journals (Sweden)

    Fu-Wu Yan

    2014-05-01

    Full Text Available The main aim of the study is to get the temperature and backpressure of a car engine exhaust gas which goes through the EGR-cooler. So the internal fluid flow and heat transfer process of the EGR cooler must be studied more clearly, numerical simulations are applied. Based on the strong coupling method, gas-solid-liquid three phases coupling model of the typical heat transfer unit is established. According to the coupling result, the heat flux of the tube’s outside surface is gained and then mapped to the inner surface of the cooler’s water. The water model is set up based on the separation coupling method. According to the analysis of the calculation, the detailed pressure and temperature distribution of the gas, water and solid are obtained. From the distribution cloud, we know the changes of the parameters along the fluid flows streamline.

  18. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors.

    Science.gov (United States)

    Tirunehe, Gossaye; Norddahl, B

    2016-04-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air-water and air-CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas-liquid mediums. CMC solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas-liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (U(G)) range of 0.0004-0.0025 m/s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular membrane sparger achieved greater interfacial area and an enhanced overall mass transfer coefficient (K(L)a) by a factor of 1.2-1.9 compared to the flat sheet membrane.

  19. Information transfer model of natural processes: from the ideal gas law to the distance dependent redshift

    CERN Document Server

    Fielitz, P

    2009-01-01

    We consider a general information transfer model which comprises any natural process which is able to transfer information and which can be characterised by only two independent process variables. We further postulate that these independent process variables serve as source and destination of information during a natural process. To define information which is directly related to the process variables, we apply the definition of information originally formulated by Hartley. We demonstrate that the proposed information transfer model yields well known laws, which, as yet, have not been directly related to information theory, such as the ideal gas law, the radioactive decay law, the formation law of vacancies in single crystals, and Fick's first law. Further, for the propagation of photons from a point source the information transfer model shows that any detector device, if at rest relative to the point source, will measure a redshift relative to the photon wavelength which is emitted from the point source. Tha...

  20. Observations of the gas stream in the mass transfer binary HR 2142 prime 1

    Science.gov (United States)

    Peters, G. J.

    1981-01-01

    The mass transfer binary system HR 2142 was observed at selected phases with the high resolution spectrograph on IUE. The observations were scheduled throughout the interval 0.91 phi 0.00 in order to allow viewing of the light of the primary star through the gas stream as it presents different orientations to the line of sight. Numerous UV lines formed in the gas stream were identified. The strengths and velocity variations displayed by these lines are compared with those observed in the ground based spectral region. As part of a preliminary analysis of the IUE data, column densities and velocities from Si III (4), Si IV (1), and Ti III (1) are used to deduce electron densities in the gas stream as well as its thickness. Possible evidence for stratification in the gas stream is presented.

  1. Fluorescence resonance energy transfer of gas-phase ions under ultra high vacuum and ambient conditions.

    Science.gov (United States)

    Frankevich, Vladimir; Chagovets, Vitaliy; Widjaja, Fanny; Barylyuk, Konstantin; Yang, Zhiyi; Zenobi, Renato

    2014-05-21

    We report evidence for fluorescence resonance energy transfer (FRET) of gas-phase ions under ultra high vacuum conditions (10(-9) mbar) inside a mass spectrometer as well as under ambient conditions inside an electrospray plume. Two different FRET pairs based on carboxyrhodamine 6G (donor) and ATTO590 or Bodipy TR (acceptor) dyes were examined and their gas-phase optical properties were studied. Our measurements indicate a different behavior for the two FRET pairs, which can be attributed to their different conformations in the gas phase. Upon desolvation via electrospray ionization, one of the FRET pairs undergoes a conformational change that leads to disappearance of FRET. This study shows the promise of FRET to obtain a direct correlation between solution and gas-phase structures.

  2. The influence of polymeric membrane gas spargers on hydrodynamics and mass transfer in bubble column bioreactors

    DEFF Research Database (Denmark)

    Tirunehe, Gossay; Norddahl, B.

    2016-01-01

    Gas sparging performances of a flat sheet and tubular polymeric membranes were investigated in 3.1 m bubble column bioreactor operated in a semi batch mode. Air–water and air–CMC (Carboxymethyl cellulose) solutions of 0.5, 0.75 and 1.0 % w/w were used as interacting gas–liquid mediums. CMC...... solutions were employed in the study to simulate rheological properties of bioreactor broth. Gas holdup, bubble size distribution, interfacial area and gas–liquid mass transfer were studied in the homogeneous bubbly flow hydrodynamic regime with superficial gas velocity (UG) range of 0.0004–0.0025 m....../s. The study indicated that the tubular membrane sparger produced the highest gas holdup and densely populated fine bubbles with narrow size distribution. An increase in liquid viscosity promoted a shift in bubble size distribution to large stable bubbles and smaller specific interfacial area. The tubular...

  3. Using eddy covariance to estimate air-sea gas transfer velocity for oxygen

    Science.gov (United States)

    Andersson, Andreas; Rutgersson, Anna; Sahlée, Erik

    2016-07-01

    Air-sea gas transfer velocity for O2 is calculated using directly measured fluxes with the eddy covariance technique. It is a direct method and is frequently used to determine fluxes of heat, humidity, and CO2, but has not previously been used to estimate transfer velocities for O2, using atmospheric eddy covariance data. The measured O2 fluxes are upward directed, in agreement with the measured air-sea gradient of the O2 concentration, and opposite to the direction of the simultaneously measured CO2 fluxes. The transfer velocities estimated from measurements are compared with prominent wind speed parameterizations of the transfer velocity for CO2 and O2, previously established from various measurement techniques. Our result indicates stronger wind speed dependence for the transfer velocity of O2 compared to CO2 starting at intermediate wind speeds. This stronger wind speed dependence appears to coincide with the onset of whitecap formation in the flux footprint and the strong curvature of a cubic wind-dependent function for the transfer velocity provides the best fit to the data. Additional data using the measured O2 flux and an indirect method (based on the Photosynthetic Quotient) to estimate oxygen concentration in water, support the stronger wind dependence for the transfer velocity of O2 compared to CO2.

  4. Heat Transfer Characteristics of Liquid-Gas Taylor Flows incorporating Microencapsulated Phase Change Materials

    Science.gov (United States)

    Howard, J. A.; Walsh, P. A.

    2014-07-01

    This paper presents an investigation on the heat transfer characteristics associated with liquid-gas Taylor flows in mini channels incorporating microencapsulated phase change materials (MPCM). Taylor flows have been shown to result in heat transfer enhancements due to the fluid recirculation experienced within liquid slugs which is attributable to the alternating liquid slug and gas bubble flow structure. Microencapsulated phase change materials (MPCM) also offer significant potential with increased thermal capacity due to the latent heat required to cause phase change. The primary aim of this work was to examine the overall heat transfer potential associated with combining these two novel liquid cooling technologies. By investigating the local heat transfer characteristics, the augmentation/degradation over single phase liquid cooling was quantified while examining the effects of dimensionless variables, including Reynolds number, liquid slug length and gas void fraction. An experimental test facility was developed which had a heated test section and allowed MPCM-air Taylor flows to be subjected to a constant heat flux boundary condition. Infrared thermography was used to record high resolution experimental wall temperature measurements and determine local heat transfer coefficients from the thermal entrance point. 30.2% mass particle concentration of the MPCM suspension fluid was examined as it provided the maximum latent heat for absorption. Results demonstrate a significant reduction in experimental wall temperatures associated with MPCM-air Taylor flows when compared with the Graetz solution for conventional single phase coolants. Total enhancement in the thermally developed region is observed to be a combination of the individual contributions due to recirculation within the liquid slugs and also absorption of latent heat. Overall, the study highlights the potential heat transfer enhancements that are attainable within heat exchange devices employing MPCM

  5. Oil and gas technology transfer activities and potential in eight major producing states. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    1993-07-01

    In 1990, the Interstate Oil and Gas Compact Commission (the Compact) performed a study that identified the structure and deficiencies of the system by which oil and gas producers receive information about the potential of new technologies and communicate their problems and technology needs back to the research community. The conclusions of that work were that major integrated companies have significantly more and better sources of technology information than independent producers. The majors also have significantly better mechanisms for communicating problems to the research and development (R&D) community. As a consequence, the Compact recommended analyzing potential mechanisms to improve technology transfer channels for independents and to accelerate independents acceptance and use of existing and emerging technologies. Building on this work, the Compact, with a grant from the US Department Energy, has reviewed specific technology transfer organizations in each of eight major oil producing states to identify specific R&D and technology transfer organizations, characterize their existing activities, and identify potential future activities that could be performed to enhance technology transfer to oil and gas producers. The profiles were developed based on information received from organizations,follow-up interviews, site visit and conversations, and participation in their sponsored technology transfer activities. The results of this effort are reported in this volume. In addition, the Compact has also developed a framework for the development of evaluation methodologies to determine the effectiveness of technology transfer programs in performing their intended functions and in achieving desired impacts impacts in the producing community. The results of that work are provided in a separate volume.

  6. Study on the Holdup and Mass Transfer Performances for Gas-Liquid-Liquid System in a Screen Plate Column

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The gas and dispersed phase holdups and mass transfer coefficients of liquid-iquid were determined for gas-liquid-liquid three phase system in a screen plate column. The flow pattern of gas-liquid-liquid three phase system was studied under different gas velocities. The shape factors showed the geometric properties of screen plates and the corrected drop characteristic velocities were introduced. The phase holdup in two phases was correlated. The research results indicated that mass transfer coefficient for liquid-liquid system in a column with screen plates and gas agitation was found to increase apparently.

  7. Dynamic modeling of fixed-bed adsorption of flue gas using a variable mass transfer model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jehun; Lee, Jae W. [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2016-02-15

    This study introduces a dynamic mass transfer model for the fixed-bed adsorption of a flue gas. The derivation of the variable mass transfer coefficient is based on pore diffusion theory and it is a function of effective porosity, temperature, and pressure as well as the adsorbate composition. Adsorption experiments were done at four different pressures (1.8, 5, 10 and 20 bars) and three different temperatures (30, 50 and 70 .deg. C) with zeolite 13X as the adsorbent. To explain the equilibrium adsorption capacity, the Langmuir-Freundlich isotherm model was adopted, and the parameters of the isotherm equation were fitted to the experimental data for a wide range of pressures and temperatures. Then, dynamic simulations were performed using the system equations for material and energy balance with the equilibrium adsorption isotherm data. The optimal mass transfer and heat transfer coefficients were determined after iterative calculations. As a result, the dynamic variable mass transfer model can estimate the adsorption rate for a wide range of concentrations and precisely simulate the fixed-bed adsorption process of a flue gas mixture of carbon dioxide and nitrogen.

  8. Wall heat transfer in gas-fired furnaces: Effect of radiation modelling

    Directory of Open Access Journals (Sweden)

    Vondál J.

    2015-06-01

    Full Text Available The purpose of this work is to study heat transfer to cooled walls in a MW-scale laboratory furnace with a dominating thermal radiation component. Experiment is performed in a specially designed combustion chamber with segmental water-cooled walls and profile of absorbed heat flux is measured along the flame. Non-premixed natural gas flame is stabilized by a guide-vane swirler. The unsteady governing equations of turbulent flow are solved by a finite-volume code with a two-equation k-ε realizable turbulence model, a combination of first-order and second-order upwind schemes and implicit time integration. The coupling of pressure with velocity is treated by SIMPLE (semi-implicit method for pressure-linked equations algorithm. Radiative heat transfer as the main heat transfer method is modelled with special care by discrete ordinates method and gas absorption coefficient is calculated by two alternatives of WSGGM (weighted sum of grey gases model. The predicted total heat transfer rate is found to depend strongly on method chosen for the computation of mean beam length. The results of numerical simulations show that overall heat transfer in a process furnace can be successfully predicted, while heat flux profile along the flame is more difficult to predict accurately. Good engineering accuracy is nevertheless achievable with reasonable computational resources. The trend of deviations is reported, which is useful for the interpretation of practical predictions of process furnaces (fired heaters.

  9. Studies on fluid dynamics of the flow field and gas transfer in orbitally shaken tubes.

    Science.gov (United States)

    Zhu, Li-Kuan; Song, Bo-Yan; Wang, Zhen-Long; Monteil, Dominique T; Shen, Xiao; Hacker, David L; De Jesus, Maria; Wurm, Florian M

    2017-01-01

    Orbitally shaken cylindrical bioreactors [OrbShake bioreactors (OSRs)] without an impeller or sparger are increasingly being used for the suspension cultivation of mammalian cells. Among small volume OSRs, 50-mL tubes with a ventilated cap (OSR50), originally derived from standard laboratory centrifuge tubes with a conical bottom, have found many applications including high-throughput screening for the optimization of cell cultivation conditions. To better understand the fluid dynamics and gas transfer rates at the liquid surface in OSR50, we established a three-dimensional simulation model of the unsteady liquid forms (waves) in this vessel. The studies verified that the operating conditions have a large effect on the interfacial surface. The volumetric mass transfer coefficient (kL a) was determined experimentally and from simulations under various working conditions. We also determined the liquid-phase mass transfer coefficient (kL ) and the specific interfacial area (a) under different conditions to demonstrate that the value of a affected the gas transfer rate more than did the value of kL . High oxygen transfer rates, sufficient for supporting the high-density culture of mammalian cells, were found. Finally, the average axial velocity of the liquid was identified to be an important parameter for maintaining cells in suspension. Overall these studies provide valuable insights into the preferable operating conditions for the OSR50, such as those needed for cell cultures requiring high oxygen levels. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:192-200, 2017.

  10. Mass Transfer in a closed stirred gas/liquid contactor: Part 2: The liquid phase mass transfer coefficient kL

    NARCIS (Netherlands)

    Koetsier, W.T.; Thoenes, D.

    1973-01-01

    The liquid phase mass transfer coefficient kL for the absorption of oxygen in tap water and in ionic solutions has been calculated from the quotien It is concluded that the liquid phase mass transfer coefficient is roughly proportional to the stirrer speed. The gas fraction e apparently has little

  11. Verification of Methodology for Determination of Deposit Thickness on Heat Transfer Surface of Natural Gas Coolers

    Directory of Open Access Journals (Sweden)

    Miroslav PŘÍHODA

    2010-12-01

    Full Text Available The paper describes briefly an original methodology for the determination of the deposit thickness on the inside heat transfer surface of natural gas cooler and a procedure of its verification at the cooler CH_R of the booster station KS01 in Velké Kapušany. The methodology is based on the measurement of the degree of the gas cooling. It has the universal validity and can be used to determine the thickness of the deposits of all types of coolers working on any booster station.

  12. Examination of charge transfer in Au/YSZ for high-temperature optical gas sensing

    Energy Technology Data Exchange (ETDEWEB)

    Baltrus, John P. [U.S. DOE; Ohodnicki, Paul R. [U.S. DOE

    2014-01-01

    Au-nanoparticle incorporated oxide thin film materials demonstrate significant promise as functionalsensor materials for high temperature optical gas sensing in severe environments relevant for fossil andnuclear based power generation. The Au/yttria-stabilized zirconia (YSZ) system has been extensivelystudied in the literature and serves as a model system for fundamental investigations that seek to betterunderstand the mechanistic origin of the plasmonic gas sensing response. In this work, X-ray photoelec-tron spectroscopy techniques are applied to Au/YSZ films in an attempt to provide further experimentalevidence for a proposed sensing mechanism involving a change in free carrier density of Au nanoparticles due to charge transfer.

  13. Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade

    Science.gov (United States)

    Azad, Gm S.; Han, Je-Chin; Boyle, Robert J.

    2000-01-01

    Experimental investigations are performed to measure the detailed heat transfer coefficient and static pressure distributions on the squealer tip of a gas turbine blade in a five-bladed stationary linear cascade. The blade is a 2-dimensional model of a modem first stage gas turbine rotor blade with a blade tip profile of a GE-E(sup 3) aircraft gas turbine engine rotor blade. A squealer (recessed) tip with a 3.77% recess is considered here. The data on the squealer tip are also compared with a flat tip case. All measurements are made at three different tip gap clearances of about 1%, 1.5%, and 2.5% of the blade span. Two different turbulence intensities of 6.1% and 9.7% at the cascade inlet are also considered for heat transfer measurements. Static pressure measurements are made in the mid-span and near-tip regions, as well as on the shroud surface opposite to the blade tip surface. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and an exit Reynolds number based on the axial chord of 1.1 x 10(exp 6). A transient liquid crystal technique is used to measure the heat transfer coefficients. Results show that the heat transfer coefficient on the cavity surface and rim increases with an increase in tip clearance. 'Me heat transfer coefficient on the rim is higher than the cavity surface. The cavity surface has a higher heat transfer coefficient near the leading edge region than the trailing edge region. The heat transfer coefficient on the pressure side rim and trailing edge region is higher at a higher turbulence intensity level of 9.7% over 6.1 % case. However, no significant difference in local heat transfer coefficient is observed inside the cavity and the suction side rim for the two turbulence intensities. The squealer tip blade provides a lower overall heat transfer coefficient when compared to the flat tip blade.

  14. Heat and mass transfer rates during flow of dissociated hydrogen gas over graphite surface

    Science.gov (United States)

    Nema, V. K.; Sharma, O. P.

    1986-01-01

    To improve upon the performance of chemical rockets, the nuclear reactor has been applied to a rocket propulsion system using hydrogen gas as working fluid and a graphite-composite forming a part of the structure. Under the boundary layer approximation, theoretical predictions of skin friction coefficient, surface heat transfer rate and surface regression rate have been made for laminar/turbulent dissociated hydrogen gas flowing over a flat graphite surface. The external stream is assumed to be frozen. The analysis is restricted to Mach numbers low enough to deal with the situation of only surface-reaction between hydrogen and graphite. Empirical correlations of displacement thickness, local skin friction coefficient, local Nusselt number and local non-dimensional heat transfer rate have been obtained. The magnitude of the surface regression rate is found low enough to ensure the use of graphite as a linear or a component of the system over an extended period without loss of performance.

  15. NACOWA experiments on LMFBR cover gas aerosols, heat transfer, and fission product enrichment

    Energy Technology Data Exchange (ETDEWEB)

    Minges, J.; Schuetz, W.

    1993-12-01

    Fifteen different NACOWA test series were carried out. The following items were investigated: sodium mass concentration in the cover gas, sodium aerosol particle size, radiative heat transfer across the cover gas, total heat transfer across the cover gas, sodium deposition on the cover plate, temperature profiles across the cover gas, phenomena if the argon cover gas is replaced by helium, enrichment of cesium, iodine, and zinc in the aerosol and in the deposits. The conditions were mainly related to the design parameters of the EFR. According to the first consistent design, a pool temperature of 545 C and a roof temperature of only 120 C were foreseen at a cover gas height of 85 cm. The experiments were carried out in a stainless steel test vessel of 0.6 m diameter and 1.14 m height. Pool temperature (up to 545 C), cover gas height (12.5 cm, 33 cm, and others), and roof temperature (from 110 C to 450 C) were the main parameters. (orig./HP) [Deutsch] Es wurden fuenfzehn verschiedene NACOWA-Versuchsreihen durchgefuehrt. Folgende Themen wurden behandelt: Natrium-Massenkonzentration im Schutzgas, Natriumaerosol-Partikelgroesse, Strahlungswaermeuebergang durch das Schutzgas, Gesamtwaermeuebergang durch das Schutzgas, Natriumablagerung am Deckel, Temperaturprofile im Schutzgas, Phaenomene beim Uebergang von Argon-Schutzgas auf Helium-Schutzgas, Anreicherung von Caesium, Jod und Zink im Aerosol und in den Ablagerungen. Die Versuchsbedingungen wurden hauptsaechlich durch die Auslegungsparameter des EFR bestimmt. Beim `first consistent design` war eine Pooltemperatur von 545 C und eine Dachtemperatur von nur 120 C bei 85 cm Argon-Schutzgashoehe vorgesehen. Die Experimente wurden in einem Edelstahlbehaelter von 0,6 m Durchmesser und 1,14 m Hoehe durchgefuehrt. Pooltemperatur (bis 545 C), Schutzgashoehe (12,5 cm, 33 cm und andere) sowie Deckeltemperatur (von 100 C bis 450 C) waren die wichtigsten experimentellen Parameter. (orig./HP)

  16. Analysis of small scale turbulent structures and the effect of spatial scales on gas transfer

    Science.gov (United States)

    Schnieders, Jana; Garbe, Christoph

    2014-05-01

    The exchange of gases through the air-sea interface strongly depends on environmental conditions such as wind stress and waves which in turn generate near surface turbulence. Near surface turbulence is a main driver of surface divergence which has been shown to cause highly variable transfer rates on relatively small spatial scales. Due to the cool skin of the ocean, heat can be used as a tracer to detect areas of surface convergence and thus gather information about size and intensity of a turbulent process. We use infrared imagery to visualize near surface aqueous turbulence and determine the impact of turbulent scales on exchange rates. Through the high temporal and spatial resolution of these types of measurements spatial scales as well as surface dynamics can be captured. The surface heat pattern is formed by distinct structures on two scales - small-scale short lived structures termed fish scales and larger scale cold streaks that are consistent with the footprints of Langmuir Circulations. There are two key characteristics of the observed surface heat patterns: 1. The surface heat patterns show characteristic features of scales. 2. The structure of these patterns change with increasing wind stress and surface conditions. In [2] turbulent cell sizes have been shown to systematically decrease with increasing wind speed until a saturation at u* = 0.7 cm/s is reached. Results suggest a saturation in the tangential stress. Similar behaviour has been observed by [1] for gas transfer measurements at higher wind speeds. In this contribution a new model to estimate the heat flux is applied which is based on the measured turbulent cell size und surface velocities. This approach allows the direct comparison of the net effect on heat flux of eddies of different sizes and a comparison to gas transfer measurements. Linking transport models with thermographic measurements, transfer velocities can be computed. In this contribution, we will quantify the effect of small scale

  17. Mass transfer correlation in flotation of palm oil by colloidal gas aphrons

    Energy Technology Data Exchange (ETDEWEB)

    Hashim, M.A.; Dey, A.; Hasan, S.; Sen Gupta, B. [Inst. of Post Graduate Studies and Research, University of Malaya, Kuala Lumpur (Malaysia)

    1999-11-01

    Colloidal gas aphrons (CGAs) are micron-sized bubbles, which are produced by stirring a dilute surfactant solution at a high speed. In this work, CGAs have been used to clarify oily wastewater by flotation technique. The CGAs sparging rate was a critical factor that governed the efficiency of the process. A model for the determination of the mass transfer coefficient is also developed for the purpose of process design. (orig.)

  18. Two-flux method for radiation heat transfer in anisotropic gas-particles media

    Institute of Scientific and Technical Information of China (English)

    WANG Fei; CEN Kefa; T. Girasole; A. Garo; G. Gréhan; YAN Jianhua

    2004-01-01

    Two-flux method can be used, as a simplification for the radiative heat transfer, to predict heat flux in a slab consisting of gas and particles. In the original two-flux method (Schuster, 1905 and Schwarzschild, 1906), the radiation field was assumed to be isotropic. But for gas-particles mixture in combustion environments, the scatterings of particles are usually anisotropic, and the original two-flux method gives critical errors when ignoring this anisotropy. In the present paper, a multilayer four-flux model developed by Rozé et al. (2001) is extended to calculate the radiation heat flux in a slab containing participating particles and gas mixture. The analytic resolution of the radiative transfer equation in the framework of a two-flux approach is presented. The average crossing parameter ε And the forward scattering ratio ζ are defined to describe the anisotropy of the radiative field. To validate the model, the radiation transfer in a slab has been computed. Comparisons with the exact analytical result of Modest (1993) and the original two-flux model show the exactness and the improvement. The emissivity of a slab containing flyash/CO2/H2O mixture is obtained using the new model. The result is identical with that of Goodwin (1989).

  19. Progress towards understanding and predicting heat transfer in the turbine gas path

    Science.gov (United States)

    Simoneau, Robert J.; Simon, Frederick F.

    1993-01-01

    A new era is dawning in the ability to predict convection heat transfer in the turbine gas path. We feel that the technical community now has the capability to mount a major assault on this problem, which has eluded significant progress for a long time. In this paper we hope to make a case for this bold statement by reviewing the state of the art in three major and related areas, which we believe are indispensable to the understanding and accurate prediction of turbine gas path heat transfer: configuration-specific experiments, fundamental physics and model development, and code development. We begin our review with the configuration-specific experiments, whose data have provided the big picture and guided both the fundamental modeling research and the code development. Following that, we examine key modeling efforts and comment on what will be needed to incorporate them into the codes. In this region we concentrate on bypass transition, 3D endwalls, and film cooling. We then review progress and directions in the development of computer codes to predict turbine gas path heat transfer. Finally, we cite examples and make observations on the more recent efforts to do all this work in a simultaneous, interactive, and more synergistic manner. We conclude with an assessment of progress, suggestions for how to use the current state of the art, and recommendations for the future.

  20. Phonon Boltzmann equation-based discrete unified gas kinetic scheme for multiscale heat transfer

    CERN Document Server

    Guo, Zhaoli

    2016-01-01

    Numerical prediction of multiscale heat transfer is a challenging problem due to the wide range of time and length scales involved. In this work a discrete unified gas kinetic scheme (DUGKS) is developed for heat transfer in materials with different acoustic thickness based on the phonon Boltzmann equation. With discrete phonon direction, the Boltzmann equation is discretized with a second-order finite-volume formulation, in which the time-step is fully determined by the Courant-Friedrichs-Lewy (CFL) condition. The scheme has the asymptotic preserving (AP) properties for both diffusive and ballistic regimes, and can present accurate solutions in the whole transition regime as well. The DUGKS is a self-adaptive multiscale method for the capturing of local transport process. Numerical tests for both heat transfers with different Knudsen numbers are presented to validate the current method.

  1. A two-dimensional position sensitive gas chamber with scanned charge transfer readout

    Science.gov (United States)

    Gómez, F.; Iglesias, A.; Lobato, R.; Mosquera, J.; Pardo, J.; Pena, J.; Pazos, A.; Pombar, M.; Rodríguez, A.

    2003-10-01

    We have constructed and tested a two-dimensional position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position-dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solution reduces considerably the number of electronic readout channels needed to cover large detector areas. The use of a 25 μm thick kapton etched circuit allows high charge transfer efficiency with a low gating voltage, consequently needing a very simple commutating circuit. The present prototype covers 8×8 cm2 with a pixel size of 1.27×1.27 mm2. Depending on the intended use and beam characteristics a smaller effective pixel is feasible and larger active areas are possible. This detector can be used for X-ray or other continuous beam intensity profile monitoring.

  2. Study of Mass Transfer in Gas Blowing Processes for Silicon Purification

    Science.gov (United States)

    Altenberend, Jochen; Chichignoud, Guy; Delannoy, Yves

    2017-03-01

    Boron removal processes are crucial to make the metallurgical route for silicon refining for solar cells competitive and thus reduce the cost of solar energy. The rate-limiting step was investigated in silicon purification processes for boron removal based on gas blowing, to gain better understanding that should help to improve the design of such processes. We calculate the boron concentration in the off-gas that corresponds to chemical equilibrium between the gas and silicon. The real concentration in the off-gas ranges between 9 and 30 pct of this theoretical value calculated using Gibbs free energies reported in literature. Purification experiments with varying temperature and hydrogen concentration were done to evaluate whether limited chemical reaction rates induce deviation from chemical equilibrium. The experiments and data from literature show that the chemical reactions at the surface of the melt are close to chemical equilibrium, thus the purification rate is limited by mass transfer in the gas phase near the interface. Based on this, recommendations for the design of a gas blowing purification process are given.

  3. A simple technique for continuous measurement of time-variable gas transfer in surface waters

    Science.gov (United States)

    Bohlke, Johnkarl F.; Harvey, Judson W.; Busenberg, Eurybiades; Tobias, Craig R.

    2009-01-01

    Mass balance models of dissolved gases in streams, lakes, and rivers serve as the basis for estimating wholeecosystem rates for various biogeochemical processes. Rates of gas exchange between water and the atmosphere are important and error-prone components of these models. Here we present a simple and efficient modification of the SF6 gas tracer approach that can be used concurrently while collecting other dissolved gas samples for dissolved gas mass balance studies in streams. It consists of continuously metering SF6-saturated water directly into the stream at a low rate of flow. This approach has advantages over pulse injection of aqueous solutions or bubbling large amounts of SF6 into the stream. By adding the SF6 as a saturated solution, we minimize the possibility that other dissolved gas measurements are affected by sparging and/or bubble injecta. Because the SF6 is added continuously we have a record of changing gas transfer velocity (GTV) that is contemporaneous with the sampling of other nonconservative ambient dissolved gases. Over a single diel period, a 30% variation in GTV was observed in a second-order stream (Sugar Creek, Indiana, USA). The changing GTV could be attributed in part to changes in temperature and windspeed that occurred on hourly to diel timescales.

  4. Bond-specific dissociation following excitation energy transfer for distance constraint determination in the gas phase.

    Science.gov (United States)

    Hendricks, Nathan G; Lareau, Nichole M; Stow, Sarah M; McLean, John A; Julian, Ryan R

    2014-09-24

    Herein, we report chemistry that enables excitation energy transfer (EET) to be accurately measured via action spectroscopy on gaseous ions in an ion trap. It is demonstrated that EET between tryptophan or tyrosine and a disulfide bond leads to excited state, homolytic fragmentation of the disulfide bond. This phenomenon exhibits a tight distance dependence, which is consistent with Dexter exchange transfer. The extent of fragmentation of the disulfide bond can be used to determine the distance between the chromophore and disulfide bond. The chemistry is well suited for the examination of protein structure in the gas phase because native amino acids can serve as the donor/acceptor moieties. Furthermore, both tyrosine and tryptophan exhibit unique action spectra, meaning that the identity of the donating chromophore can be easily determined in addition to the distance between donor/acceptor. Application of the method to the Trpcage miniprotein reveals distance constraints that are consistent with a native-like fold for the +2 charge state in the gas phase. This structure is stabilized by several salt bridges, which have also been observed to be important previously in proteins that retain native-like structures in the gas phase. The ability of this method to measure specific distance constraints, potentially at numerous positions if combined with site-directed mutagenesis, significantly enhances our ability to examine protein structure in the gas phase.

  5. An evaluation of gas transfer velocity parameterizations during natural convection using DNS

    Science.gov (United States)

    Fredriksson, Sam T.; Arneborg, Lars; Nilsson, Hâkan; Zhang, Qi; Handler, Robert A.

    2016-02-01

    Direct numerical simulations (DNS) of free surface flows driven by natural convection are used to evaluate different methods of estimating air-water gas exchange at no-wind conditions. These methods estimate the transfer velocity as a function of either the horizontal flow divergence at the surface, the turbulent kinetic energy dissipation beneath the surface, the heat flux through the surface, or the wind speed above the surface. The gas transfer is modeled via a passive scalar. The Schmidt number dependence is studied for Schmidt numbers of 7, 150 and 600. The methods using divergence, dissipation and heat flux estimate the transfer velocity well for a range of varying surface heat flux values, and domain depths. The two evaluated empirical methods using wind (in the limit of no wind) give reasonable estimates of the transfer velocity, depending however on the surface heat flux and surfactant saturation. The transfer velocity is shown to be well represented by the expression, ks=A |Bν|1/4 Sc-n, where A is a constant, B is the buoyancy flux, ν is the kinematic viscosity, Sc is the Schmidt number, and the exponent n depends on the water surface characteristics. The results suggest that A=0.39 and n≈1/2 and n≈2/3 for slip and no-slip boundary conditions at the surface, respectively. It is further shown that slip and no-slip boundary conditions predict the heat transfer velocity corresponding to the limits of clean and highly surfactant contaminated surfaces, respectively. This article was corrected on 22 MAR 2016. See the end of the full text for details.

  6. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongying; Huang, Guangming, E-mail: gmhuang@ustc.edu.cn

    2015-03-31

    Graphical abstract: Direct and humidity independent mass spectrometry analysis of gas phase chemicals could be achieved via ambient proton transfer ionization, ion intensity was found to be stable with humidity ranged from ∼10% to ∼100%. - Highlights: • A humidity independent mass spectrometric method for gas phase samples analysis. • A universal and good sensitivity method. • The method can real time identify plant released raw chemicals. - Abstract: In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m{sup −3}, ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages.

  7. The gas-liquid mass transfer coefficient (k(L)a) in the gas-liquid Multi-stage Agitated Contactor (MAC)

    NARCIS (Netherlands)

    Breman, B.B; Beenackers, A.A C M; Bouma, M.J; VanderWerf, M.H.

    1996-01-01

    Data on the volumetric liquid-side gas-liquid mass transfer coefficient, k(L)a, in a Multi-stage Agitated Contractor (MAC) are reported for three gas-liquid systems (air-water, helium-n-octane, and air-Monoethylene Glycol (MEG)). k(L)a (s(-1)) was determined using a dynamic method with moderately so

  8. Effects of gas bubble production on heat transfer from a volumetrically heated liquid pool

    Science.gov (United States)

    Bull, Geoffrey R.

    Aqueous solutions of uranium salts may provide a new supply chain to fill potential shortfalls in the availability of the most common radiopharmaceuticals currently in use worldwide, including Tc99m which is a decay product of Mo99. The fissioning of the uranium in these solutions creates Mo99 but also generates large amounts of hydrogen and oxygen from the radiolysis of the water. When the dissolved gases reach a critical concentration, bubbles will form in the solution. Bubbles in the solution affect both the fission power and the heat transfer out of the solution. As a result, for safety and production calculations, the effects of the bubbles on heat transfer must be understood. A high aspect ratio tank was constructed to simulate a section of an annulus with heat exchangers on the inner and outer steel walls to provide cooling. Temperature measurements via thermocouples inside the tank and along the outside of the steel walls allowed the calculation of overall and local heat transfer coefficients. Different air injection manifolds allowed the exploration of various bubble characteristics and patterns on heat transfer from the pool. The manifold type did not appear to have significant impact on the bubble size distributions in water. However, air injected into solutions of magnesium sulfate resulted in smaller bubble sizes and larger void fractions than those in water at the same injection rates. One dimensional calculations provide heat transfer coefficient values as functions of the superficial gas velocity in the pool.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-08-15

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

  10. Surfactant control of gas transfer velocity along an offshore coastal transect: results from a laboratory gas exchange tank

    Science.gov (United States)

    Pereira, R.; Schneider-Zapp, K.; Upstill-Goddard, R. C.

    2016-07-01

    Understanding the physical and biogeochemical controls of air-sea gas exchange is necessary for establishing biogeochemical models for predicting regional- and global-scale trace gas fluxes and feedbacks. To this end we report the results of experiments designed to constrain the effect of surfactants in the sea surface microlayer (SML) on the gas transfer velocity (kw; cm h-1), seasonally (2012-2013) along a 20 km coastal transect (North East UK). We measured total surfactant activity (SA), chromophoric dissolved organic matter (CDOM) and chlorophyll a (Chl a) in the SML and in sub-surface water (SSW) and we evaluated corresponding kw values using a custom-designed air-sea gas exchange tank. Temporal SA variability exceeded its spatial variability. Overall, SA varied 5-fold between all samples (0.08 to 0.38 mg L-1 T-X-100), being highest in the SML during summer. SML SA enrichment factors (EFs) relative to SSW were ˜ 1.0 to 1.9, except for two values (0.75; 0.89: February 2013). The range in corresponding k660 (kw for CO2 in seawater at 20 °C) was 6.8 to 22.0 cm h-1. The film factor R660 (the ratio of k660 for seawater to k660 for "clean", i.e. surfactant-free, laboratory water) was strongly correlated with SML SA (r ≥ 0.70, p ≤ 0.002, each n = 16). High SML SA typically corresponded to k660 suppressions ˜ 14 to 51 % relative to clean laboratory water, highlighting strong spatiotemporal gradients in gas exchange due to varying surfactant in these coastal waters. Such variability should be taken account of when evaluating marine trace gas sources and sinks. Total CDOM absorbance (250 to 450 nm), the CDOM spectral slope ratio (SR = S275 - 295/S350 - 400), the 250 : 365 nm CDOM absorption ratio (E2 : E3), and Chl a all indicated spatial and temporal signals in the quantity and composition of organic matter in the SML and SSW. This prompts us to hypothesise that spatiotemporal variation in R660 and its relationship with SA is a consequence of compositional

  11. Experimental study of condensation heat transfer in the presence of noncondensable gas on the vertical tube

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Yeong-Jun; Choi, Dong-Jae; Lee, Yeon-Gun [Jeju National University, Jeju (Korea, Republic of); Kim, Sin [Chung-Ang University, Seoul (Korea, Republic of)

    2015-05-15

    The Passive Containment Cooling System (PCCS) that will be introduced in the next generation nuclear power plant removes released energy to containment through the condensation heat transfer phenomenon in the event of the loss of coolant accident(LOCA) or main steam line break(MSLB). The released steam is mixed with the air inside the containment and condensed on the tube bundle's outer surface of PCCS. In this study, an experimental study is performed to investigate the condensation heat transfer in the presence of noncondensable gas on vertical tube. Experiments were conducted using a tube with 1000 mm in length and 40 mm in outer diameter tube. The experimental data are obtained at pressure of 2, 3, 4 bar and the air mass fraction varied from 0.1 to 0.7. The experimental results are compared to the prediction of existing correlations. In a vertical tube with 40 mm in O.D. and 1000 mm in height, three sets of experiments to measure the condensation heat transfer coefficient are performed at 2, 3, 4 bar. Experimental results show that the condensation heat transfer coefficient reduces with an increase of the noncondensable mass fraction. The results are compared with the prediction of existing correlations by Uchida, Tagami and Dehbi. The compared result shows that these correlations underestimate the experimental results. That's because Uchida's and Tagami's correlations do not reflect all the effects of primary physical parameters and Dehbi's experiment did not maintain the uniform gas mixtures state inside chamber and has significant wall temperature gradient along the tube height. As further works, a new correlation will be proposed based on the experimental results. In addition, the heat transfer enhancement by using a finned tube is to be experimentally investigated.

  12. Characterization of carbon dioxide transfer in a hollow fiber membrane module as a solution for gas-liquid transfer in microgravity conditions.

    Science.gov (United States)

    Farges, Berangere; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-F.

    In microgravity, one of the major difficulties encountered in closed photosynthetic reactors is the gas-liquid transfer with the necessity to provide CO2 (carbon source, pH control) and to recover the produced O2 . Indeed, reduced gravity is expected to modify gas liquid transfer and liquid phase mixing characteristics inside photobioreactors conceived to regenerate atmosphere of closed life-support systems. To obtain efficient mass transfer conditions and mixing of phases, several solutions are possible: use of rotating reactor (centrifugal field), use of forced, co-current convective reactor with gas-liquid separator and use of membrane modules. In terms of space process engineering, the membrane reactor can be a valuable alternative in which the gas and liquid phases are separated with a selectively permeable membrane. The rate-limiting factors in this reactor were demonstrated to be the surface of membrane A needed for diffusion of gases and the CO2 and O2 mass transfer coefficients in the liquid phase kL. How-ever, the major advantages of the membrane reactor are that it is composed of a hydrophobic membrane (here PTFE) which showed a high hydrophobicity, an important chemical resis-tance, a very long term stability and overall which is favourable to gas transfer. Moreover, the volumetric mass transfer coefficients are sufficiently high to build compact systems with small footprints, no complex rotating devices and lighter weights. This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient CO kL 2 obtained in case of an absorption experiment at pH = 8 using the

  13. Coefficient of solid-gas heat transfer in particle fixed bed; Coeficiente de transferencia de calor gas-solido em leito fixo de particulas

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes Filho, Francisco

    1991-03-01

    The work presents a study on heat transfer between gas and solid phases for fixed beds in the absence of mass transfer and chemical reactions. Mathematical models presented in the literature were analyzed concerning to the assumptions made on axial dispersion in the fluid phase and interparticle thermal conductivity. Heat transfer coefficients and their dependency on flow conditions, particles and packed bed characteristics were experimentally determined through the solution of the previous mathematical models. Pressure drop behaviour for the packed beds used for the heat transfer study was also included. (author) 32 refs., 12 figs.

  14. Mass transfer in gas-liquid stirred reactor with various triple-impeller combinations☆

    Institute of Scientific and Technical Information of China (English)

    Jinjin Zhang; Zhengming Gao; Yating Cai; Ziqi Cai; Jie Yang; Yuyun Bao

    2016-01-01

    The gassed power demand and volumetric mass transfer coefficient (kLa) were investigated in a fully baffled, dished-base stirred vessel with a diameter of 0.30 m agitated by five triple-impeller combinations. Six types of impellers (six-half-elliptical-blade disk turbine (HEDT), four-wide-blade hydrofoil impeller (WH) pumping down (D) and pumping up (U), parabolic-blade disk turbine (PDT), and CBY narrow blade (N) and wide blade (W)) were used to form five combinations identified by PDT + 2CBYN, PDT + 2CBYW, PDT + 2WHD, HEDT + 2WHD and HEDT + 2WHU, respectively. The results show that the relative power demand of HEDT+2WHU is higher than that of other four impeller combinations under all operating conditions. At low superficial gas velocity (uG), kLa differences among impeller combinations are not obvious. However, when uG is high, PDT+2WHD shows the best mass transfer performance and HEDT+2WHU shows the worst mass trans-fer performance under al operating conditions. At high uG and a given power input, the impel er combinations with high agitation speed and big projection cross-sectional area lead to relatively high values of kLa. Based on the experimental data, the regressed correlations of gassed power number with Froude number and gas flow number, and kLa with power consumption and superficial gas velocity are obtained for five different impeller combinations, which could be used as guidance for industrial design.

  15. On which timescales do gas transfer velocities control North Atlantic CO2 flux variability?

    Science.gov (United States)

    Couldrey, Matthew P.; Oliver, Kevin I. C.; Yool, Andrew; Halloran, Paul R.; Achterberg, Eric P.

    2016-05-01

    The North Atlantic is an important basin for the global ocean's uptake of anthropogenic and natural carbon dioxide (CO2), but the mechanisms controlling this carbon flux are not fully understood. The air-sea flux of CO2, F, is the product of a gas transfer velocity, k, the air-sea CO2 concentration gradient, ΔpCO2, and the temperature- and salinity-dependent solubility coefficient, α. k is difficult to constrain, representing the dominant uncertainty in F on short (instantaneous to interannual) timescales. Previous work shows that in the North Atlantic, ΔpCO2 and k both contribute significantly to interannual F variability but that k is unimportant for multidecadal variability. On some timescale between interannual and multidecadal, gas transfer velocity variability and its associated uncertainty become negligible. Here we quantify this critical timescale for the first time. Using an ocean model, we determine the importance of k, ΔpCO2, and α on a range of timescales. On interannual and shorter timescales, both ΔpCO2 and k are important controls on F. In contrast, pentadal to multidecadal North Atlantic flux variability is driven almost entirely by ΔpCO2; k contributes less than 25%. Finally, we explore how accurately one can estimate North Atlantic F without a knowledge of nonseasonal k variability, finding it possible for interannual and longer timescales. These findings suggest that continued efforts to better constrain gas transfer velocities are necessary to quantify interannual variability in the North Atlantic carbon sink. However, uncertainty in k variability is unlikely to limit the accuracy of estimates of longer-term flux variability.

  16. Gas-liquid mass transfer in a cross-flow hollow fiber module : Analytical model and experimental validation

    NARCIS (Netherlands)

    Dindore, V. Y.; Versteeg, G. F.

    2005-01-01

    The cross-flow operation of hollow fiber membrane contactors offers many advantages and is preferred over the parallel-flow contactors for gas-liquid mass transfer operations. However, the analysis of such a cross-flow membrane gas-liquid contactor is complicated due to the change in concentrations

  17. Microbial synthesis gas utilization and ways to resolve kinetic and mass-transfer limitations.

    Science.gov (United States)

    Yasin, Muhammad; Jeong, Yeseul; Park, Shinyoung; Jeong, Jiyeong; Lee, Eun Yeol; Lovitt, Robert W; Kim, Byung Hong; Lee, Jinwon; Chang, In Seop

    2015-02-01

    Microbial conversion of syngas to energy-dense biofuels and valuable chemicals is a potential technology for the efficient utilization of fossils (e.g., coal) and renewable resources (e.g., lignocellulosic biomass) in an environmentally friendly manner. However, gas-liquid mass transfer and kinetic limitations are still major constraints that limit the widespread adoption and successful commercialization of the technology. This review paper provides rationales for syngas bioconversion and summarizes the reaction limited conditions along with the possible strategies to overcome these challenges. Mass transfer and economic performances of various reactor configurations are compared, and an ideal case for optimum bioreactor operation is presented. Overall, the challenges with the bioprocessing steps are highlighted, and potential solutions are suggested. Future research directions are provided and a conceptual design for a membrane-based syngas biorefinery is proposed.

  18. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1999-10-31

    During FY99, the Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions. PTTC's national organization has active grassroots programs that connect with independents through its 10 Regional Lead Organizations (RLOs). These activities--including technology workshops, resource centers, websites, newsletters, and other outreach efforts--are guided by regional Producer Advisory Groups (PAGs). The role of the national headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. This technical progress report summarizes PTTC's accomplishments during FY99, which lay the groundwork for further growth in the future.

  19. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2000-05-01

    During FY00, the Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions. PTTC's national organization has active grassroots programs that connect with independents through its 10 Regional Lead Organizations (RLOs). These activities--including technology workshops, resource centers, websites, newsletters, and other outreach efforts--are guided by regional Producer Advisory Groups (PAGs). The role of the national headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. This technical progress report summarizes PTTC's accomplishments during FY00, which lay the groundwork for further growth in the future.

  20. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Shestakov Igor A.

    2015-01-01

    Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.

  1. Unit operations for gas-liquid mass transfer in reduced gravity environments

    Science.gov (United States)

    Pettit, Donald R.; Allen, David T.

    1992-01-01

    Basic scaling rules are derived for converting Earth-based designs of mass transfer equipment into designs for a reduced gravity environment. Three types of gas-liquid mass transfer operations are considered: bubble columns, spray towers, and packed columns. Application of the scaling rules reveals that the height of a bubble column in lunar- and Mars-based operations would be lower than terrestrial designs by factors of 0.64 and 0.79 respectively. The reduced gravity columns would have greater cross-sectional areas, however, by factors of 2.4 and 1.6 for lunar and Martian settings. Similar results were obtained for spray towers. In contract, packed column height was found to be nearly independent of gravity.

  2. A high-power ultrasonic microreactor and its application in gas-liquid mass transfer intensification.

    Science.gov (United States)

    Dong, Zhengya; Yao, Chaoqun; Zhang, Xiaoli; Xu, Jie; Chen, Guangwen; Zhao, Yuchao; Yuan, Quan

    2015-02-21

    The combination of ultrasound and microreactor is an emerging and promising area, but the report of designing high-power ultrasonic microreactor (USMR) is still limited. This work presents a robust, high-power and highly efficient USMR by directly coupling a microreactor plate with a Langevin-type transducer. The USMR is designed as a longitudinal half wavelength resonator, for which the antinode plane of the highest sound intensity is located at the microreactor. According to one dimension design theory, numerical simulation and impedance analysis, a USMR with a maximum power of 100 W and a resonance frequency of 20 kHz was built. The strong and uniform sound field in the USMR was then applied to intensify gas-liquid mass transfer of slug flow in a microfluidic channel. Non-inertial cavitation with multiple surface wave oscillation was excited on the slug bubbles, enhancing the overall mass transfer coefficient by 3.3-5.7 times.

  3. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Donald Duttlinger

    1999-12-01

    During FY99, the Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions. PTfC's national organization has active grassroots programs that connect with independents through its 10 Regional Lead Organizations (RLOs). These activities--including technology workshops, resource centers, websites, newsletters, and other outreach efforts--are guided by regional Producer Advisory Groups (PAGs). The role of the national headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. This technical progress report summarizes PTTC's accomplishments during FY99, which lay the groundwork for further growth in the future.

  4. Heat transfer analysis of fuel assemblies in a heterogeneous gas core nuclear rocket

    Science.gov (United States)

    Watanabe, Yoichi; Appelbaum, Jacob; Diaz, Nils; Maya, Isaac

    1991-01-01

    Heat transfer problems of a heterogeneous gaseous core nuclear rocket were studied. The reactor core consists of 1.5-m long hexagonal fuel assemblies filled with pressurized uranium tetrafluoride (UF4) gas. The fuel gas temperature ranges from 3500 to 7000 K at a nominal operating condition of 40 atm. Each fuel assembly has seven coolant tubes, through which hydrogen propellant flows. The propellant temperature is not constrained by the fuel temperature but by the maximum temperature of the graphite coolant tube. For a core achieving a fission power density of 1000 MW/cu m, the propellant core exit temperature can be as high as 3200 K. The physical size of a 1250 MW gaseous core nuclear rocket is comparable with that of a NERVA-type solid core nuclear rocket. The engine can deliver a specific impulse of 1020 seconds and a thrust of 330 kN.

  5. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2003-04-30

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and natural gas producers make timely, informed technology decisions. Networking opportunities that occur with a Houston Headquarters (HQ) location are increasing name awareness. Focused efforts by Executive Director Don Duttlinger to interact with large independents, national service companies and some majors are continuing to supplement the support base of the medium to smaller industry participants around the country. PTTC is now involved in many of the technology-related activities that occur in high oil and natural gas activity areas. Access to technology remains the driving force for those who do not have in-house research and development capabilities and look to the PTTC to provide services and options for increased efficiency.

  6. Gas-grain energy transfer in solar nebula shock waves: Implications for the origin of chondrules

    Science.gov (United States)

    Hood, L. L.; Horanyi, M.

    1993-01-01

    Meteoritic chondrules provide evidence for the occurrence of rapid transient heating events in the protoplanetary nebula. Astronomical evidence suggests that gas dynamic shock waves are likely to be excited in protostellar accretion disks by processes such as protosolar mass ejections, nonaxisymmetric structures in an evolving disk, and impact on the nebula surface of infalling 'clumps' of circumstellar gas. Previous detailed calculations of gas-grain energy and momentum transfer have supported the possibility that such shock waves could have melted pre-existing chondrule-sized grains. The main requirement for grains to reach melting temperatures in shock waves with plausibly low Mach numbers is that grains existed in dust-rich zones (optical depth greater than 1) where radiative cooling of a given grain can be nearly balanced by radiation from surrounding grains. Localized dust-rich zones also provide a means of explaining the apparent small spatial scale of heating events. For example, the scale size of at least some optically thick dust-rich zones must have been relatively small (less than 10 kilometers) to be consistent with petrologic evidence for accretion of hot material onto cold chondrules. The implied number density of mm-sized grains for these zones would be greater than 30 m(exp -3). In this paper, we make several improvements of our earlier calculations to include radiation self-consistently in the shock jump conditions, and we include heating of grains due to radiation from the shocked gas. In addition, we estimate the importance of momentum feedback of dust concentrations onto the shocked gas which would tend to reduce the efficiency of gas dynamic heating of grains in the center of the dust cloud.

  7. Humidity independent mass spectrometry for gas phase chemical analysis via ambient proton transfer reaction.

    Science.gov (United States)

    Zhu, Hongying; Huang, Guangming

    2015-03-31

    In this work, a humidity independent mass spectrometric method was developed for rapid analysis of gas phase chemicals. This method is based upon ambient proton transfer reaction between gas phase chemicals and charged water droplets, in a reaction chamber with nearly saturate humidity under atmospheric pressure. The humidity independent nature enables direct and rapid analysis of raw gas phase samples, avoiding time- and sample-consuming sample pretreatments in conventional mass spectrometry methods to control sample humidity. Acetone, benzene, toluene, ethylbenzene and meta-xylene were used to evaluate the analytical performance of present method. The limits of detection for benzene, toluene, ethylbenzene and meta-xylene are in the range of ∼0.1 to ∼0.3 ppbV; that of benzene is well below the present European Union permissible exposure limit for benzene vapor (5 μg m(-3), ∼1.44 ppbV), with linear ranges of approximately two orders of magnitude. The majority of the homemade device contains a stainless steel tube as reaction chamber and an ultrasonic humidifier as the source of charged water droplets, which makes this cheap device easy to assemble and facile to operate. In addition, potential application of this method was illustrated by the real time identification of raw gas phase chemicals released from plants at different physiological stages.

  8. Preliminary characterization of carbon dioxide transfer in a hollow fiber membrane module as a possible solution for gas-liquid transfer in microgravity conditions

    Science.gov (United States)

    Farges, Bérangère; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-François

    2012-01-01

    In microgravity, one of the major challenge encountered in biological life support systems (BLSS) is the gas-liquid transfer with, for instance, the necessity to provide CO2 (carbon source, pH control) and to recover the evolved O2 in photobioreactors used as atmosphere bioregenerative systems.This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module used as a possible efficient solution to the microgravity gas-liquid transfer. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient kLCO obtained in case of absorption experiments at pH 8 using the hollow fiber membrane module. The consistency of the proposed method, based on a gas and liquid phase balances verifying carbon conservation enables a very accurate determination of the kLCO value as a main limiting step of the whole process. Nevertheless, further experiments are still needed to demonstrate that the proposed method could serve in the future as reference method for mass transfer coefficient determination if using membrane modules for BLSS in reduced or microgravity conditions.

  9. Gas-Liquid Mass Transfer in a Slurry Bubble Column Reactor under High Temperature andHigh Pressure

    Institute of Scientific and Technical Information of China (English)

    杨卫国; 王金福; 金涌

    2001-01-01

    The gas-liquid mass transfer of H2 and CO in a high temperature and high-pressure three-phase slurry bubble column reactor is studied. The gas-liquid volumetric mass transfer coefficients kLa are obtained by measuring the dissolution rate of H2 and CO. The influences of the main operation conditions, such as temperature, pressure,superficial gas velocity and solid concentration, are studied systematically. Two empirical correlations are proposed to predict kLa values for H2 and CO in liquid paraffln/solid particles slurry bubble column reactors.

  10. Effect of Schmidt number on mass transfer across a sheared gas-liquid interface in a wind-driven turbulence.

    Science.gov (United States)

    Takagaki, Naohisa; Kurose, Ryoichi; Kimura, Atsushi; Komori, Satoru

    2016-11-14

    The mass transfer across a sheared gas-liquid interface strongly depends on the Schmidt number. Here we investigate the relationship between mass transfer coefficient on the liquid side, kL, and Schmidt number, Sc, in the wide range of 0.7 ≤ Sc ≤ 1000. We apply a three-dimensional semi direct numerical simulation (SEMI-DNS), in which the mass transfer is solved based on an approximated deconvolution model (ADM) scheme, to wind-driven turbulence with mass transfer across a sheared wind-driven wavy gas-liquid interface. In order to capture the deforming gas-liquid interface, an arbitrary Lagrangian-Eulerian (ALE) method is employed. Our results show that similar to the case for flat gas-liquid interfaces, kL for the wind-driven wavy gas-liquid interface is generally proportional to Sc(-0.5), and can be roughly estimated by the surface divergence model. This trend is endorsed by the fact that the mass transfer across the gas-liquid interface is controlled mainly by streamwise vortices on the liquid side even for the wind-driven turbulence under the conditions of low wind velocities without wave breaking.

  11. Effect of Schmidt number on mass transfer across a sheared gas-liquid interface in a wind-driven turbulence

    Science.gov (United States)

    Takagaki, Naohisa; Kurose, Ryoichi; Kimura, Atsushi; Komori, Satoru

    2016-11-01

    The mass transfer across a sheared gas-liquid interface strongly depends on the Schmidt number. Here we investigate the relationship between mass transfer coefficient on the liquid side, kL, and Schmidt number, Sc, in the wide range of 0.7 ≤ Sc ≤ 1000. We apply a three-dimensional semi direct numerical simulation (SEMI-DNS), in which the mass transfer is solved based on an approximated deconvolution model (ADM) scheme, to wind-driven turbulence with mass transfer across a sheared wind-driven wavy gas-liquid interface. In order to capture the deforming gas-liquid interface, an arbitrary Lagrangian-Eulerian (ALE) method is employed. Our results show that similar to the case for flat gas-liquid interfaces, kL for the wind-driven wavy gas-liquid interface is generally proportional to Sc‑0.5, and can be roughly estimated by the surface divergence model. This trend is endorsed by the fact that the mass transfer across the gas-liquid interface is controlled mainly by streamwise vortices on the liquid side even for the wind-driven turbulence under the conditions of low wind velocities without wave breaking.

  12. Evaluation of the swell effect on the air-sea gas transfer in the coastal zone

    Science.gov (United States)

    Gutiérrez-Loza, Lucía; Ocampo-Torres, Francisco J.

    2016-04-01

    Air-sea gas transfer processes are one of the most important factors regarding global climate and long-term global climate changes. Despite its importance, there is still a huge uncertainty on how to better parametrize these processes in order to include them on the global climate models. This uncertainty exposes the need to increase our knowledge on gas transfer controlling mechanisms. In the coastal regions, breaking waves become a key factor to take into account when estimating gas fluxes, however, there is still a lack of information and the influence of the ocean surface waves on the air-sea interaction and gas flux behavior must be validated. In this study, as part of the "Sea Surface Roughness as Air-Sea Interaction Control" project, we evaluate the effect of the ocean surface waves on the gas exchange in the coastal zone. Direct estimates of the flux of CO2 (FCO2) and water vapor (FH2O) through eddy covariance, were carried out from May 2014 to April 2015 in a coastal station located at the Northwest of Todos Santos Bay, Baja California, México. For the same period, ocean surface waves are recorded using an Acoustic Doppler Current Profiler (Workhorse Sentinel, Teledyne RD Instruments) with a sampling rate of 2 Hz and located at 10 m depth about 350 m away from the tower. We found the study area to be a weak sink of CO2 under moderate wind and wave conditions with a mean flux of -1.32 μmol/m2s. The correlation between the wind speed and FCO2 was found to be weak, suggesting that other physical processes besides wind may be important factors for the gas exchange modulation at coastal waters. The results of the quantile regression analysis computed between FCO2 and (1) wind speed, (2) significant wave height, (3) wave steepness and (4) water temperature, show that the significant wave height is the most correlated parameter with FCO2; Nevertheless, the behavior of their relation varies along the probability distribution of FCO2, with the linear regression

  13. Gas transfer under high wind and its dependence on wave breaking and sea state

    Science.gov (United States)

    Brumer, Sophia; Zappa, Christopher; Fairall, Christopher; Blomquist, Byron; Brooks, Ian; Yang, Mingxi

    2016-04-01

    Quantifying greenhouse gas fluxes on regional and global scales relies on parameterizations of the gas transfer velocity K. To first order, K is dictated by wind speed (U) and is typically parameterized as a non-linear functions of U. There is however a large spread in K predicted by the traditional parameterizations at high wind speed. This is because a large variety of environmental forcing and processes (Wind, Currents, Rain, Waves, Breaking, Surfactants, Fetch) actually influence K and wind speed alone cannot capture the variability of air-water gas exchange. At high wind speed especially, breaking waves become a key factor to take into account when estimating gas fluxes. The High Wind Gas exchange Study (HiWinGS) presents the unique opportunity to gain new insights on this poorly understood aspects of air-sea interaction under high winds. The HiWinGS cruise took place in the North Atlantic during October and November 2013. Wind speeds exceeded 15 m s-1 25% of the time, including 48 hrs with U10 > 20 m s-1. Continuous measurements of turbulent fluxes of heat, momentum, and gas (CO2, DMS, acetone and methanol) were taken from the bow of the R/V Knorr. The wave field was sampled by a wave rider buoy and breaking events were tracked in visible imagery was acquired from the port and starboard side of the flying bridge during daylight hours at 20Hz. Taking advantage of the range of physical forcing and wave conditions sampled during HiWinGS, we test existing parameterizations and explore ways of better constraining K based on whitecap coverage, sea state and breaking statistics contrasting pure windseas to swell dominated periods. We distinguish between windseas and swell based on a separation algorithm applied to directional wave spectra for mixed seas, system alignment is considered when interpreting results. The four gases sampled during HiWinGS ranged from being mostly waterside controlled to almost entirely airside controlled. While bubble-mediated transfer

  14. Calculation of the drag and heat transfer from a sphere in the gas flow in a cylindrical channel

    Science.gov (United States)

    Simakov, N. N.

    2016-09-01

    A numerical experiment on the simulation of heat transfer from a sphere to a gas flow in a cylindrical channel in the Stokes and transient flow regimes has been described. Radial and axial profiles of the gas temperature and the dependences of drag coefficient C d of the body and Nusselt number Nu on Reynolds number Re have been calculated and analyzed. The problem of the influence of the early drag crisis for a sphere on its heat transfer to the gas flow has been considered. The estimation of this phenomenon has shown that the early drag crisis of the sphere in a strongly turbulent flow causes a reduction in heat transfer from the sphere to the gas by three to six times (in approximately the same proportion as for its drag coefficient).

  15. Thermo-mechanical modeling of turbulent heat transfer in gas-solid flows including particle collisions

    Energy Technology Data Exchange (ETDEWEB)

    Mansoori, Zohreh; Saffar-Avval, Majid; Basirat-Tabrizi, Hassan; Ahmadi, Goodarz; Lain, Santiago

    2002-12-01

    A thermo-mechanical turbulence model is developed and used for predicting heat transfer in a gas-solid flow through a vertical pipe with constant wall heat flux. The new four-way interaction model makes use of the thermal k{sub {theta}}-{tau}{sub {theta}} equations, in addition to the hydrodynamic k-{tau} transport, and accounts for the particle-particle and particle-wall collisions through a Eulerian/Lagrangian formulation. The simulation results indicate that the level of thermal turbulence intensity and the heat transfer are strongly affected by the particle collisions. Inter-particle collisions attenuate the thermal turbulence intensity near the wall but somewhat amplify the temperature fluctuations in the pipe core region. The hydrodynamic-to-thermal times-scale ratio and the turbulent Prandtl number in the region near the wall increase due to the inter-particle collisions. The results also show that the use of a constant or the single-phase gas turbulent Prandtl number produces error in the thermal eddy diffusivity and thermal turbulent intensity fields. Simulation results also indicate that the inter-particle contact heat conduction during collision has no significant effect in the range of Reynolds number and particle diameter studied.

  16. Effects of magnetic fields on improving mass transfer in flue gas desulfurization using a fluidized bed

    Science.gov (United States)

    Zhang, Qi; Gui, Keting; Wang, Xiaobo

    2016-02-01

    The effects of magnetic fields on improving the mass transfer in flue gas desulfurization using a fluidized bed are investigated in the paper. In this research, the magnetically fluidized bed (MFB) is used as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. Lime slurry is continuously sprayed into the reactor. As a consequence, the desulfurization reaction and the slurry drying process take place simultaneously in the MFB. In this paper, the effects of ferromagnetic particles and external magnetic fields on the desulphurization efficiency are studied and compared with that of quartz particles as the fluidized particles. Experimental results show that the ferromagnetic particles not only act as a platform for lime slurry to precipitate on like quartz particles, but also take part in the desulfurization reaction. The results also show that the specific surface area of ferromagnetic particles after reaction is enlarged as the magnetic intensity increases, and the external magnetic field promotes the oxidation of S(IV), improving the mass transfer between sulphur and its sorbent. Hence, the efficiency of desulphurization under the effects of external magnetic fields is higher than that in general fluidized beds.

  17. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    1998-10-31

    In pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions, the Petroleum Technology Transfer Council (PTTC) functions as a cohesive national organization that implements industry's directives through active regional programs. The role of the national headquarters (HQ) organization includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. PTTC relies on 10 Regional Lead Organizations (RLOs) as its main program delivery mechanism to industry. Through its regions, PTTC connects with independent oil and gas producers--through technology workshops, resources centers, websites, newsletters, and other outreach efforts. The organization effectively combines federal, state, and industry funding to achieve important goals for all of these sectors. This integrated funding base, combined with industry volunteers guiding PTTC's activities and the dedication of national and regional staff, are achieving notable results. PTTC is increasingly recognized as a critical resource for information and access to technologies, especially for smaller companies. This technical progress report summarizes PTTC's accomplishments during FY98, and its strategy for achieving further growth in the future.

  18. Flow and heat transfer in gas turbine disk cavities subject to nonuniform external pressure field

    Energy Technology Data Exchange (ETDEWEB)

    Roy, R.P.; Kim, Y.W.; Tong, T.W. [Arizona State Univ., Tempe, AZ (United States)

    1995-10-01

    Injestion of hot gas from the main-stream gas path into turbine disk cavities, particularly the first-stage disk cavity, has become a serious concern for the next-generation industrial gas turbines featuring high rotor inlet temperature. Fluid temperature in the cavities increases further due to windage generated by fluid drag at the rotating and stationary surfaces. The resulting problem of rotor disk heat-up is exacerbated by the high disk rim temperature due to adverse (relatively flat) temperature profile of the mainstream gas in the annular flow passage of the turbine. A designer is concerned about the level of stresses in the turbine rotor disk and its durability, both of which are affected significantly by the disk temperature distribution. This distribution also plays a major role in the radial position of the blade tip and thus, in establishing the clearance between the tip and the shroud. To counteract mainstream gas ingestion as well as to cool the rotor and the stator disks, it is necessary to inject cooling air (bled from the compressor discharge) into the wheel space. Since this bleeding of compressor air imposes a penalty on the engine cycle performance, the designers of disk cavity cooling and sealing systems need to accomplish these tasks with the minimum possible amount of bleed air without risking disk failure. This requires detailed knowledge of the flow characteristics and convective heat transfer in the cavity. The flow in the wheel space between the rotor and stator disks is quite complex. It is usually turbulent and contains recirculation regions. Instabilities such as vortices oscillating in space have been observed in the flow. It becomes necessary to obtain both a qualitative understanding of the general pattern of the fluid motion as well as a quantitative map of the velocity and pressure fields.

  19. Dynamic Force Reduction and Heat Transfer Improvement for Horizontal Tubes in Large-Particle Gas-Fluidized Beds

    Institute of Scientific and Technical Information of China (English)

    Yusumi Nagahashi; John R.Grace; Kok-Seng Lim; Yutaka Asako

    2008-01-01

    The effects of tube bank configuration on forces and heat transfer were investigated for both two-dimensional and three-dimensional gas fluidized beds. Effective dynamic forces and heat transfer coefficients were measured for several tube bank configurations, and it was found that the average forces ate smaller than for a single tube. The heat transfer coefficient can be increased by providing sufficient space for particles to descend around both sides of the tube bank. The results provide useful guidelines for optimizing the configuration of tube banks to achieve high heat transfer coefficients while reducing tube erosion due to dynamic forces.

  20. Photochemistry with fast sample renewal using cluster beams: formation of rare-gas halides in charge-transfer reactions in NF 3-doped rare-gas clusters

    Science.gov (United States)

    Moussavizadeh, L.; von Haeften, K.; Museur, L.; Kanaev, A. V.; Castex, M. C.; von Pietrowski, R.; Möller, T.

    1999-05-01

    Charge transfer reactions in free clusters are observed in a photoluminescence study on doped rare-gas clusters (Rg clusters, Rg=Ar, Kr and Xe). Following photoexcitation into the first absorption bands of Rg clusters, fluorescence from free RgF* excimers ejected from the clusters and from Rg 2F* excimers localized in the interior of the clusters is observed. The results show that the reaction dynamics in clusters differs considerably from that in the gas and solid phase.

  1. A two-dimensional position sensitive gas chamber with scanned charge transfer readout

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, F. E-mail: faustgr@usc.es; Iglesias, A.; Lobato, R.; Mosquera, J.; Pardo, J.; Pena, J.; Pazos, A.; Pombar, M.; Rodriguez, A

    2003-10-21

    We have constructed and tested a two-dimensional position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position-dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solution reduces considerably the number of electronic readout channels needed to cover large detector areas. The use of a 25 {mu}m thick kapton etched circuit allows high charge transfer efficiency with a low gating voltage, consequently needing a very simple commutating circuit. The present prototype covers 8x8 cm{sup 2} with a pixel size of 1.27x1.27 mm{sup 2}. Depending on the intended use and beam characteristics a smaller effective pixel is feasible and larger active areas are possible. This detector can be used for X-ray or other continuous beam intensity profile monitoring.

  2. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-07-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidizing gas,(3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  3. Heat transfer to immersed horizontal tubes in gas fluidized bed dryers

    Energy Technology Data Exchange (ETDEWEB)

    Jonassen, Ola

    1999-10-01

    The main objective of this study was to construct heat pump fluidized bed dryers of the FHT type with improved dewatering capacity for a given size of the dryer. The use of heat exchangers immersed in the fluidized bed drying chambers is an important part of the FHT (Fluidized Bed High Temperature Heat Pump Dryer) concept. A pilot plant FHT dryer was built and successfully tested on fish meal raw material and seaweed. The plant included two fluidized bed drying chambers with immersed heat exchangers. The gain in water vapor of the drying air through the chambers was increased up to four times that of adiabatic drying. The energy saving concept was retained as a SMER ratio of 3.5 to 4.7 was measured in the same tests. Therefore optimization of the immersed heat exchangers was considered the most important single objective for this work. The optimization study of the heat exchangers was confined to the actual operating conditions for the dryers using: (1) Bubbling gas fluidized beds were used, (2) air as the only type of fluidising gas, (3) beds at atmospheric pressure, (4) bed temperatures below 100 {sup o}C, (5) fluidized particles of Geldart classes B and D, (6) horizontal tube banks for the immersed heat exchanger, and the influence of radiation heat transfer was ignored. The heat transfer study was confined to the fluidized bed side of the heat exchanger surface. It was concluded early in this work that the bubbles play a major role in generating the particle circulation inside the bed and hence also in heat transfer. Publications describing the most important bubble induced mechanisms contributing to high rates of heat transfer were found to be limited. Therefore the first part of this study was aimed at establishing a method for locating and measuring the size and rise velocity of bubbles inside the bed. The method established through this work using differential pressure measurements from two static pressure probes was used later in the study of heat transfer

  4. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-11-01

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of assisting U.S. independent oil and gas producers make timely, informed technology decisions by providing access to information during Fiscal Year 2002 (FY02). Functioning as a cohesive national organization, PTTC has active grassroots programs through its ten Regional Lead Organizations (RLOs) and three satellite offices that efficiently extend the program reach. They bring research and academia to the table via their association with geological surveys and engineering departments. The regional directors interact with independent oil and gas producers through technology workshops, resource centers, websites, newsletters, various technical publications and other outreach efforts. These are guided by regional Producer Advisory Groups (PAGs), who are area operators and service companies working with the regional networks. The role of the national Headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation wide technology transfer activities, and implementing a comprehensive communications effort. The organization effectively combines federal funding through the Department of Energy's (DOE) Office of Fossil Energy with state and industry funding to achieve important goals for all of these sectors. This integrated funding base is combined with industry volunteers guiding PTTC's activities and the dedication of national and regional staff to achieve notable results. PTTC is increasingly recognized as a critical resource for information and access to technologies, especially for smaller companies without direct contact with R&D efforts. The DOE participation is managed through the National Energy Technology Laboratory (NETL), which deploys a national natural gas program via the Strategic Center for Natural Gas (SCNG) and a national oil program through the National Petroleum Technology Office (NTPO). This technical progress report summarizes PTTC

  5. Natural gas large volumes measurement: going for on-line custody transfer; Medicao de grandes volumes de gas natural: rumo a transferencia de custodia on-line

    Energy Technology Data Exchange (ETDEWEB)

    Mercon, Eduardo G.; Frisoli, Caetano [PETROBRAS Transporte S.A. (TRANSPETRO), Rio de Janeiro, RJ (Brazil)

    2005-07-01

    This paper describes the structure of the natural gas flow measurement process in TRANSPETRO, and comments features and performance of existing or under-implantation equipment and systems, reviewing best practices and technology in use. This process runs through three interrelated segments: data flow measurement, strictly speaking; data transfer and acquisition; and data flow measurement certification (data consolidation to invoice). Initially, the work makes an approach to the data flow measurement segment, evaluating technical features of flow meters, and describing configurations and functions of the operating gas flow computers in TRANSPETRO's custody transfer stations. In this part it will also be presented the implantation of TRANSPETRO's system for gas chromatography data input on-line to flow computers. Further, in data transfer and acquisition, SCADA system technical aspects will be evaluated, considering communications protocols and programmable logic controllers functions in remote terminal units, and discussing their places in the measurement process. Additionally, TRANSPETRO's experience in data measurement certification tools is in discussion, as well as new upcoming tools and their potential features, from what new practices will be suggested. Finally, all the work has been conceived and carried out always aiming to the state-of-the-art technology in gas flow measurement: on-line custody transfer. (author)

  6. Proposal for data acquisition system of gas chromatograph and natural gas transfer custody via web; Proposta para um sistema de aquisicao de dados de cromatografia e medicao fiscal de gas natural via web

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Jose Paulo C.; Guimaraes, Marcelo F.; Zeitoune, Rafael J. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    In this paper, is presented a proposal of a Chromatograph and Transfer Custody Measurement Data Acquisition System through Web, complementary to the SCADA System, responsible for control and monitoring PETROBRAS Gas Pipelines, intended to comply with the requirements of the Gerencias de Qualidade e Medicao (MQD) and Planejamento Integrado da Logistica (PCL) from PETROBRAS Gas e Energia, regarding the evaluation of the quality of the natural gas that is being commercialized, as well as its billing. (author)

  7. Quasiclassical trajectory study of collisional energy transfer in toluene systems. I. Argon bath gas: Energy dependence and isotope effects

    Science.gov (United States)

    Lim, Kieran F.

    1994-05-01

    Experimental studies of collisional energy transfer from highly vibrationally excited toluene to various bath gases have recently been reported [Toselli and Barker, J. Chem. Phys. 97, 1809 (1992), and references therein]. A quasiclassical trajectory investigation for toluene in argon bath gas at 300 K for initial internal energies E'=41 000, 30 000, and 15 000 cm-1 is reported here. Collisional energy transfer is almost linearly dependent on E'. Predictions of energy transfer quantities are very sensitive to the average well depth of the assumed individual pairwise potentials, but is less sensitive to the detailed shape. Qualitative and quantitative agreement with experiment is obtained where the overall well depth is physically realistic. Isotope studies using 40Ar and pseudohelium (4Ar) bath gases indicate that energy transfer is independent of the mass of the bath-gas collider, but perdeuteration increases 1/2 by 13% over the undeuterated values.

  8. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2001-05-01

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and natural gas producers make timely, informed technology decisions. PTTC's Board made a strategic decision to relocate the Headquarters (HQ) office from Washington, DC to Houston, Texas. Driving force behind relocation was to better connect with independent producers, but cost savings could also be realized. Relocation was accomplished in late December 2000, with the HQ office being fully operational by January 2001. Early indications are that the HQ relocation is, in fact, enabling better networking with senior executives of independents in the Houston oil community. New Board leadership, elected in March 2001, will continue to effectively guide PTTC.

  9. Explicit analytical wave solutions of unsteady 1D ideal gas flow with friction and heat transfer

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Several families of algebraically explicit analytical wavesolutions are derived for the unsteady 1D ideal gas flow with friction and heat-transfer, which include one family of travelling wave solutions, three families of standing wave solutions and one standing wave solution. \\{Among\\} them, the former four solution families contain arbitrary functions, so actually there are infinite analytical wave solutions having been derived. Besides their very important theoretical meaning, such analytical wave solutions can guide the development of some new equipment, and can be the benchmark solutions to promote the development of computational fluid dynamics. For example, we can use them to check the accuracy, convergence and effectiveness of various numerical computational methods and to improve the numerical computation skills such as differential schemes, grid generation ways and so on.

  10. Improvement and modelling of hexenal transfer in liquid-gas reactor.

    Science.gov (United States)

    Ben Akacha, Najla; Guizani, Om Elkhir; Gargouri, Mohamed

    2007-12-01

    The aim of the present work is to improve the extraction of an aromatic compound, 2E-hexenal, from a continuous liquid-gas reactor. Having an improved process to recover hexenal could be of interest to obtain this chemical if produced by any biotechnological process. The experimental program proposed on the basis of a full 23 factorial design demonstrated that the conditions optima for the extraction are 40 degrees C as a reactor temperature and -10 degrees C as a temperature of trap for a nitrogen flow of 45 mL s-1. These conditions allowed to recover more than 75% of hexenal, when this compound was stripping by a nitrogen stream from the liquid phase. The mass transfer was theoretically and experimentally studied. The model predictions were validated against experimental results obtained for a reactor, and good correlation was observed for a simulation.

  11. The Gas Transfer through Polar Sea ice experiment: Insights into the rates and pathways that determine geochemical fluxes

    Science.gov (United States)

    Lovely, A.; Loose, B.; Schlosser, P.; McGillis, W.; Zappa, C.; Perovich, D.; Brown, S.; Morell, T.; Hsueh, D.; Friedrich, R.

    2015-12-01

    Sea ice is a defining feature of the polar marine environment. It is a critical domain for marine biota and it regulates ocean-atmosphere exchange, including the exchange of greenhouse gases such as CO2 and CH4. In this study, we determined the rates and pathways that govern gas transport through a mixed sea ice cover. N2O, SF6, 3He, 4He, and Ne were used as gas tracers of the exchange processes that take place at the ice-water and air-water interfaces in a laboratory sea ice experiment. Observation of the changes in gas concentrations during freezing revealed that He is indeed more soluble in ice than in water; Ne is less soluble in ice, and the larger gases (N2O and SF6) are mostly excluded during the freezing process. Model estimates of gas diffusion through ice were calibrated using measurements of bulk gas content in ice cores, yielding gas transfer velocity through ice (kice) of ˜5 × 10-4 m d-1. In comparison, the effective air-sea gas transfer velocities (keff) ranged up to 0.33 m d-1 providing further evidence that very little mixed-layer ventilation takes place via gas diffusion through columnar sea ice. However, this ventilation is distinct from air-ice gas fluxes driven by sea ice biogeochemistry. The magnitude of keff showed a clear increasing trend with wind speed and current velocity beneath the ice, as well as the combination of the two. This result indicates that gas transfer cannot be uniquely predicted by wind speed alone in the presence of sea ice.

  12. The Application of Discontinuous Galerkin Methods in Conjugate Heat Transfer Simulations of Gas Turbines

    Directory of Open Access Journals (Sweden)

    Zeng-Rong Hao

    2014-11-01

    Full Text Available The performance of modern heavy-duty gas turbines is greatly determined by the accurate numerical predictions of thermal loading on the hot-end components. The purpose of this paper is: (1 to present an approach applying a novel numerical technique—the discontinuous Galerkin (DG method—to conjugate heat transfer (CHT simulations, develop the engineering-oriented numerical platform, and validate the feasibility of the methodology and tool preliminarily; and (2 to utilize the constructed platform to investigate the aerothermodynamic features of a typical transonic turbine vane with convection cooling. Fluid dynamic and solid heat conductive equations are discretized into explicit DG formulations. A centroid-expanded Taylor basis is adopted for various types of elements. The Bassi-Rebay method is used in the computation of gradients. A coupled strategy based on a data exchange process via numerical flux on interface quadrature points is simply devised. Additionally, various turbulence Reynolds-Averaged-Navier-Stokes (RANS models and the local-variable-based transition model γ-Reθ are assimilated into the integral framework, combining sophisticated modelling with the innovative algorithm. Numerical tests exhibit good consistency between computational and analytical or experimental results, demonstrating that the presented approach and tool can handle well general CHT simulations. Application and analysis in the turbine vane, focusing on features around where there in cluster exist shock, separation and transition, illustrate the effects of Bradshaw’s shear stress limitation and separation-induced-transition modelling. The general overestimation of heat transfer intensity behind shock is conjectured to be associated with compressibility effects on transition modeling. This work presents an unconventional formulation in CHT problems and achieves its engineering applications in gas turbines.

  13. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2000-11-01

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions during Fiscal Year 2000 (FY00). Functioning as a cohesive national organization, PTTC has active grassroots programs through its ten Regional Lead Organizations (RLOs) who bring research and academia to the table via their association with geological surveys and engineering departments. The regional directors connect with independent oil and gas producers through technology workshops, resource centers, websites, newsletters, various technical publications and other outreach efforts. These are guided by regional Producer Advisory Groups (PAGs), who are area operators and service companies working with the Regional Lead Organizations. The role of the national headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation-wide technology transfer activities, and implementing a comprehensive communications effort. The organization effectively combines federal, state, and industry funding to achieve important goals for all of these sectors. This integrated funding base, combined with industry volunteers guiding PTTC's activities and the dedication of national and regional staff, are achieving notable results. PTTC is increasingly recognized as a critical resource for information and access to technologies, especially for smaller companies. This technical progress report summarizes PTTC's accomplishments during FY00, which lays the groundwork for further growth in the future. At a time of many industry changes and market movements, the organization has built a reputation and expectation to address industry needs of getting information distributed quickly which can impact the bottom line immediately.

  14. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Donald Duttlinger

    2001-11-01

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and gas producers make timely, informed technology decisions during Fiscal Year 2001 (FY01). Functioning as a cohesive national organization, PTTC has active grassroots programs through its ten Regional Lead Organizations (RLOs). They bring research and academia to the table via their association with geological surveys and engineering departments. The regional directors interact with independent oil and gas producers through technology workshops, resource centers, websites, newsletters, various technical publications and other outreach efforts. These are guided by regional Producer Advisory Groups (PAGs), who are area operators and service companies working with the regional networks. The role of the national Headquarters (HQ) staff includes planning and managing the PTTC program, conducting nation wide technology transfer activities, and implementing a comprehensive communications effort. The organization effectively combines federal funding through the Department of Energy's (DOE) Office of Fossil Energy, state, and industry funding to achieve important goals for all of these sectors. This integrated funding base, combined with industry volunteers guiding PTTC's activities and the dedication of national and regional staff, are achieving notable results. PTTC is increasingly recognized as a critical resource for information and access to technologies, especially for smaller companies without direct contact to R&D efforts. This technical progress report summarizes PTTC's accomplishments during FY01, which lays the groundwork for further growth in the future. At a time of many industry changes and wide market movements, the organization itself is adapting to change. PTTC has built a reputation and expectation among producers and other industry participants to quickly distribute information addressing technical needs. The organization

  15. Investigation on hydrodynamics and mass transfer characteristics of a gas-liquid ejector using three-dimensional CFD modeling

    Energy Technology Data Exchange (ETDEWEB)

    Utomo, Tony; Jin, Zhenhua; Rahman, MSq; Jeong, Hyo Min; Chung, Han Shik [Gyeongsang National University, Jinju (Korea, Republic of)

    2008-09-15

    An investigation of the gas-liquid ejector has been carried out to study the influence of operating conditions and ejector geometries on the hydrodynamics and mass transfer characteristics of the ejector by using three-dimensional CFD modeling. The CFD results were validated with experimental data. Flow field analysis and prediction of ejector performance were also conducted. Variations of the operating conditions were made by changing the gas-liquid flow rates ratio in the range of 0.2 to 1.2. The length to diameter ratio of mixing tube (L{sub M}/D{sub M}) was also varied from 4 to 10. CFD studies show that at L{sub M}/D{sub M}=5.5, the volumetric mass transfer coefficient increases with respect to gas flow rate. Meanwhile, at L{sub M}/D{sub M}=4, the plot of volumetric mass transfer coefficient to gas-liquid flow rate ratio reaches the maximum at gas-liquid flow rate ratio of 0.6. This study also shows that volumetric mass transfer coefficient decreases with the increase of mixing tube length

  16. Numerical analysis of heat transfer in the exhaust gas flow in a diesel power generator

    Science.gov (United States)

    Brito, C. H. G.; Maia, C. B.; Sodré, J. R.

    2016-09-01

    This work presents a numerical study of heat transfer in the exhaust duct of a diesel power generator. The analysis was performed using two different approaches: the Finite Difference Method (FDM) and the Finite Volume Method (FVM), this last one by means of a commercial computer software, ANSYS CFX®. In FDM, the energy conservation equation was solved taking into account the estimated velocity profile for fully developed turbulent flow inside a tube and literature correlations for heat transfer. In FVM, the mass conservation, momentum, energy and transport equations were solved for turbulent quantities by the K-ω SST model. In both methods, variable properties were considered for the exhaust gas composed by six species: CO2, H2O, H2, O2, CO and N2. The entry conditions for the numerical simulations were given by experimental data available. The results were evaluated for the engine operating under loads of 0, 10, 20, and 37.5 kW. Test mesh and convergence were performed to determine the numerical error and uncertainty of the simulations. The results showed a trend of increasing temperature gradient with load increase. The general behaviour of the velocity and temperature profiles obtained by the numerical models were similar, with some divergence arising due to the assumptions made for the resolution of the models.

  17. Gas Flow, Particle Acceleration, and Heat Transfer in Cold Spray: A review

    Science.gov (United States)

    Yin, Shuo; Meyer, Morten; Li, Wenya; Liao, Hanlin; Lupoi, Rocco

    2016-06-01

    Cold spraying is increasingly attracting attentions from both scientific and industrial communities due to its unique `low-temperature' coating build-up process and its potential applications in the additive manufacturing across a variety of industries. The existing studies mainly focused on the following subjects: particle acceleration and heating, coating build-up, coating formation mechanism, coating properties, and coating applications, among which particle acceleration and heating can be regarded as the premise of the other subjects because it directly determines whether particles have sufficient energy to deposit and form the coating. Investigations on particle acceleration and heating behavior in cold spraying have been widely conducted both numerically and experimentally over decades, where many valuable conclusions were drawn. However, existing literature on this topic is vast; a systematical summery and review work is still lack so far. Besides, some curtail issues involved in modeling and experiments are still not quite clear, which needs to be further clarified. Hence, a comprehensive summary and review of the literature are very necessary. In this paper, the gas flow, particle acceleration, and heat transfer behavior in the cold spray process are systematically reviewed. Firstly, a brief introduction is given to introduce the early analytical models for predicting the gas flow and particle velocity in cold spraying. Subsequently, special attention is directed towards the application of computational fluid dynamics technique for cold spray modeling. Finally, the experimental observations and measurements in cold spraying are summarized.

  18. Effect of carrier gas composition on transferred arc metal nanoparticle synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Matthias, E-mail: matthias.stein@uni-due.de; Kiesler, Dennis; Kruis, Frank Einar [University of Duisburg-Essen, Institute for Nanostructures and Technology (NST) and Center for Nanointegration Duisburg-Essen (CENIDE) (Germany)

    2013-01-15

    Metal nanoparticles are used in a great number of applications; an effective and economical production scaling-up is hence desirable. A simple and cost-effective transferred arc process is developed, which produces pure metal (Zn, Cu, and Ag) nanoparticles with high production rates, while allowing fast optimization based on energy efficiency. Different carrier gas compositions, as well as the electrode arrangements and the power input are investigated to improve the production and its efficiency and to understand the arc production behavior. The production rates are determined by a novel process monitoring method, which combines an online microbalance method with a scanning mobility particle sizer for fast production rate and size distribution measurement. Particle characterization is performed via scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction measurements. It is found that the carrier gas composition has the largest impact on the particle production rate and can increase it with orders of magnitude. This appears to be not only a result of the increased heat flux and melt temperature but also of the formation of tiny nitrogen (hydrogen) bubbles in the molten feedstock, which impacts feedstock evaporation significantly in bi-atomic gases. A production rate of sub 200 nm particles from 20 up to 2,500 mg/h has been realized for the different metals. In this production range, specific power consumptions as low as 0.08 kWh/g have been reached.

  19. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-05-31

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of helping U.S. independent oil and natural gas producers make timely, informed technology decisions. Networking opportunities that occur with a Houston Headquarters (HQ) location are increasing name awareness. Focused efforts by Executive Director Don Duttlinger to interact with large independents, national service companies and some majors are continuing to supplement the support base of the medium to smaller industry participants around the country. PTTC is now involved in many of the technology-related activities that occur in high oil and natural gas activity areas. Access to technology remains the driving force for those who do not have in-house research and development capabilities and look to the PTTC to provide services and options for increased efficiency. Looking forward to the future, the Board, Regional Lead Organization (RLO) Directors and HQ staff developed a 10-year vision outlining what PTTC needs to accomplish in supporting a national energy plan. This vision has been communicated to Department of Energy (DOE) staff and PTTC looks forward to continuing this successful federal-state-industry partnership. As part of this effort, several more examples of industry using information gained through PTTC activities to impact their bottom line were identified. Securing the industry pull on technology acceptance was the cornerstone of this directional plan.

  20. A transfer function for the prediction of gas hydrate inventories in marine sediments

    Directory of Open Access Journals (Sweden)

    M. Marquardt

    2010-02-01

    Full Text Available A simple prognostic tool for gas hydrate (GH quantification in marine sediments is presented based on a diagenetic transport-reaction model approach. One of the most crucial factors for the application of diagenetic models is the accurate formulation of microbial degradation rates of particulate organic carbon (POC and the coupled biogenic CH4 formation. Wallmann et al. (2006 suggested a kinetic formulation considering the ageing effects of POC and accumulation of reaction products (CH4, CO2 in the pore water. This model is applied to data sets of several ODP sites in order to test its general validity. Based on a thorough parameter analysis considering a wide range of environmental conditions, the POC accumulation rate (POCar in g/cm2/yr and the thickness of the gas hydrate stability zone (GHSZ in m were identified as the most important and independent controls for biogenic GH formation. Hence, depth-integrated GH inventories in marine sediments (GHI in g of CH4 per cm2 seafloor area can be estimated as:

    GHI = a · POCar · GHSZb · exp (−GHSZc/POCar/d + e

    with a = 0.00214, b = 1.234, c = −3.339, d = 0.3148, e = −10.265.

    Several tests indicate that the transfer function gives a realistic approximation of the minimum potential GH inventory of low gas flux (LGF systems. The overall advantage of the presented function is its simplicity compared to complex numerical models: only two easily accessible parameters are needed.

  1. Membrane gas transfer of methane and carbon dioxide in submerged coal deposits.

    Science.gov (United States)

    Cramer, T A; Johnson, D W; Urynowicz, A

    2009-01-01

    Membrane degassing technology may prove to be a viable alternative to current coal bed methane recovery. The proposed approach involves supplying a CO2 sweep gas to membrane fibres placed directly within a saturated coal seam to provide simultaneous CO2 sequestration and CH4 recovery. A system of ordinary differential equations derived from a mass balance on an infinitesimal fibre element enabled the calculation of lumen gas composition as a function of fibre length. The results were verified through the use of a bench-scale vessel. The model agreement appears reasonable for CH4 recovery; however, agreement for CO2 recovery declines as liquid flow decreases and lumen flow increases. To further evaluate the feasibility of the membrane degassing technology, model predictions were normalized to an average conventional CH4 recovery rate of 1.56 x 10(4) m3 d(-1). Assuming a hypothetical coal seam with a groundwater velocity of 100 cm d(-1), thickness of 36.6 m and an average depth of 107 m, 290,000 m2 or 7.73 km of fibre fabric is required, resulting in 4.11 x 10(5) m3 of CO2 transfer daily and an outlet gas composition of 95% CH4, 4.4% CO2 and 0.6% H2O vapour. Increasing groundwater velocities reduce the required membrane surface area with diminishing effect, stabilizing at 100 cm d(-1). Greater pore pressures also reduce required membrane areas, and predictions indicate that a deeper coal seam under 4.3 times greater pressure would require 98% fewer fibres as compared with the hypothetical coal seam and only 0.206 km of membrane fabric.

  2. A transfer function for the prediction of gas hydrate inventories in marine sediments

    Directory of Open Access Journals (Sweden)

    M. Marquardt

    2010-09-01

    Full Text Available A simple prognostic tool for gas hydrate (GH quantification in marine sediments is presented based on a diagenetic transport-reaction model approach. One of the most crucial factors for the application of diagenetic models is the accurate formulation of microbial degradation rates of particulate organic carbon (POC and the coupled formation of biogenic methane. Wallmann et al. (2006 suggested a kinetic formulation considering the ageing effects of POC and accumulation of reaction products (CH4, CO2 in the pore water. This model is applied to data sets of several ODP sites in order to test its general validity. Based on a thorough parameter analysis considering a wide range of environmental conditions, the POC accumulation rate (POCar in g/m2/yr and the thickness of the gas hydrate stability zone (GHSZ in m were identified as the most important and independent controls for biogenic GH formation. Hence, depth-integrated GH inventories in marine sediments (GHI in g of CH4 per cm2 seafloor area can be estimated as:

    GHI = a · POCar · GHSZb · exp (– GHSZc/POCar/d + e

    with a = 0.00214, b = 1.234, c = –3.339,

            d = 0.3148, e = –10.265.

    The transfer function gives a realistic first order approximation of the minimum GH inventory in low gas flux (LGF systems. The overall advantage of the presented function is its simplicity compared to the application of complex numerical models, because only two easily accessible parameters need to be determined.

  3. Investigation on the heat transfer characteristics during flow boiling of liquefied natural gas in a vertical micro-fin tube

    Science.gov (United States)

    Xu, Bin; Shi, Yumei; Chen, Dongsheng

    2014-03-01

    This paper presents an experimental investigation on the heat transfer characteristics of liquefied natural gas flow boiling in a vertical micro-fin tube. The effect of heat flux, mass flux and inlet pressure on the flow boiling heat transfer coefficients was analyzed. The Kim, Koyama, and two kinds of Wellsandt correlations with different Ftp coefficients were used to predict the flow boiling heat transfer coefficients. The predicted results showed that the Koyama correlation was the most accurate over the range of experimental conditions.

  4. Charge transfer reactions at interfaces between neutral gas and plasma: Dynamical effects and X-ray emission

    Science.gov (United States)

    Provornikova, E.; Izmodenov, V. V.; Lallement, R.

    2012-04-01

    Charge-transfer is the main process linking neutrals and charged particles in the interaction regions of neutral (or partly ionized) gas with a plasma. In this paper we illustrate the importance of charge-transfer with respect to the dynamics and the structure of neutral gas-plasma interfaces. We consider the following phenomena: (1) the heliospheric interface - region where the solar wind plasma interacts with the partly-ionized local interstellar medium (LISM) and (2) neutral interstellar clouds embedded in a hot, tenuous plasma such as the million degree gas that fills the so-called ``Local Bubble". In (1), we discuss several effects in the outer heliosphere caused by charge exchange of interstellar neutral atoms and plasma protons. In (2) we describe the role of charge exchange in the formation of a transition region between the cloud and the surrounding plasma based on a two-component model of the cloud-plasma interaction. In the model the cloud consists of relatively cold and dense atomic hydrogen gas, surrounded by hot, low density, fully ionized plasma. We discuss the structure of the cloud-plasma interface and the effect of charge exchange on the lifetime of interstellar clouds. Charge transfer between neutral atoms and minor ions in the plasma produces X-ray emission. Assuming standard abundances of minor ions in the hot gas surrounding the cold interstellar cloud, we estimate the X-ray emissivity consecutive to the charge transfer reactions. Our model shows that the charge-transfer X-ray emission from the neutral cloud-plasma interface may be comparable to the diffuse thermal X-ray emission from the million degree gas cavity itself.

  5. Effect of Non-Condensable Gas Mass Fraction on Condensation Heat Transfer for Water-Ethanol Vapor Mixture

    Science.gov (United States)

    Wang, Shixue; Utaka, Yoshio

    The condensation heat transfer characteristic curves for a ternary vapor mixture of water, ethanol and air (or nitrogen) under several ethanol concentrations and relatively low concentrations of air (or nitrogen) were measured. The effect of non-condensable gas on several different domains in the condensation curves was discussed. The effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable; whereas that in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, variations due to changes in non-condensable gas concentration of several characteristic points representing the curves were discussed.

  6. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    Science.gov (United States)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind shear

  7. Gas transfer velocities of methane and carbon dioxide in a subtropical shallow pond

    Science.gov (United States)

    Xiao, Shangbin

    2015-04-01

    Two diel field campaigns under different weather patterns were carried out in the summer and autumn of 2013 to measure CO2 and CH4 fluxes and to probe the rates of gas exchange across the air-water interface in a subtropical eutrophic pond in China. Bubble emissions of CH4 accounted for 99.7% and 91.67% of the total CH4 emission measured at two sites in the summer; however, no bubble was observed in the autumn. The pond was supersaturated with CO2 and CH4 during the monitoring period, and the saturation ratios (i.e., observed concentration / equilibrium concentration) of CH4 were much higher than that of CO2. Although the concentration of dissolved CO2 in the surface water collected in the autumn was 1.24 times of that in the summer, the mean diffusive CO2 flux across the water-air interface measured in the summer is almost twice compared with that in the autumn. The mean concentration of dissolved CH4 in the surface water in the autumn was around half of that in the summer, but the mean diffusive CH4 flux in the summer is 4-5 times of that in the autumn. Our data showed that the variation in gas exchange rate was dominated by differences in weather patterns and primary production. Averaged k600-CO2 and k600-CH4 (the gas transfer velocity normalized to a Schmidt number of 600) were 0.65 and 0.55 cm/h in the autumn, and 2.83 and 1.64 cm/h in the summer respectively. No statistically significant correlation was found between k600 and U10 (wind speed at 10 m height) in the summer at low wind speeds in clear weather. Diffusive gas fluxes increased during the nights, which resulted from the nighttime cooling effect of water surface and stronger turbulent mixing in the water column. The chemical enhancements for CO2 was estimated up to 1.94-fold in the hot and clear summer with low wind speeds, which might have been resulted from the increasing hydration reactions in water due to the high water temperature and active metabolism in planktonic algae. However, both the air

  8. An asymptotic preserving unified gas kinetic scheme for frequency-dependent radiative transfer equations

    Science.gov (United States)

    Sun, Wenjun; Jiang, Song; Xu, Kun; Li, Shu

    2015-12-01

    This paper presents an extension of previous work (Sun et al., 2015 [22]) of the unified gas kinetic scheme (UGKS) for the gray radiative transfer equations to the frequency-dependent (multi-group) radiative transfer system. Different from the gray radiative transfer equations, where the optical opacity is only a function of local material temperature, the simulation of frequency-dependent radiative transfer is associated with additional difficulties from the frequency-dependent opacity. For the multiple frequency radiation, the opacity depends on both the spatial location and the frequency. For example, the opacity is typically a decreasing function of frequency. At the same spatial region the transport physics can be optically thick for the low frequency photons, and optically thin for high frequency ones. Therefore, the optical thickness is not a simple function of space location. In this paper, the UGKS for frequency-dependent radiative system is developed. The UGKS is a finite volume method and the transport physics is modeled according to the ratio of the cell size to the photon's frequency-dependent mean free path. When the cell size is much larger than the photon's mean free path, a diffusion solution for such a frequency radiation will be obtained. On the other hand, when the cell size is much smaller than the photon's mean free path, a free transport mechanism will be recovered. In the regime between the above two limits, with the variation of the ratio between the local cell size and photon's mean free path, the UGKS provides a smooth transition in the physical and frequency space to capture the corresponding transport physics accurately. The seemingly straightforward extension of the UGKS from the gray to multiple frequency radiation system is due to its intrinsic consistent multiple scale transport modeling, but it still involves lots of work to properly discretize the multiple groups in order to design an asymptotic preserving (AP) scheme in all

  9. Reactor models for a series of continuous stirred tank reactors with a gas-liquid-solid leaching system: Part II. Gas-transfer control

    Science.gov (United States)

    Papangelakis, V. G.; Demopoulos, G. P.

    1992-12-01

    This article is the second in a three-article series devoted to the development of comprehensive three-phase steady-state reactor models. In this article in particular, model equations are developed for the case of a leaching reactor operating under pure gas-transfer control. That is, the transfer of a gaseous reactant at the g-1 interface is considered to be the controlling step of the process rather than the particle dissolution reaction itself. For the derivation of the appropriate model equations, the gas-transfer capacity of the reactor is coupled with the particle dissolution kinetics. Two model versions are developed. In model version 1, the dissolved gas is assumed to be distributed equally among all particles. On the basis of this assumption, a gastransfer control-shrinking core model (GTC-SCM) equation is formulated which, along with the segregated flow model, helps to calculate the conversion of the solid phase. The size distribution of the particles at the exit of the reactor is computed via a mass-particle size density (PSD) function derived with the use of the population balance model (PBM). In model version 2, the dissolved gas is assumed to be distributed among particles in proportion to their surface area. Using the PBM, equations are developed suitable for the calculation of the total specific surface area of the reacting solids and their conversion. Single as well as multiple parallel leaching reactions are considered in developing the two model versions.

  10. Application of the penetration theory for gas - Liquid mass transfer without liquid bulk : Differences with system with a bulk

    NARCIS (Netherlands)

    van Elk, E. P.; Knaap, M. C.; Versteeg, G. F.

    2007-01-01

    Frequently applied micro models for gas-liquid mass transfer all assume the presence of a liquid bulk. However, some systems are characterized by the absence of a liquid bulk, a very thin layer of liquid flows over a solid surface. An example of such a process is absorption in a column equipped with

  11. Quasiclassical trajectory study of collisional energy transfer in toluene systems. II. Helium bath gas: Energy and temperature dependences, and angular momentum transfer

    Science.gov (United States)

    Lim, Kieran F.

    1994-11-01

    The collisional deactivation of highly vibrationally excited toluene-d0 and toluene-d8 by helium bath gas has been investigated using quasiclassical trajectory simulations. Collisional energy transfer was found to increase with initial toluene internal energy, in agreement with the experiments of Toselli and Barker [J. Chem. Phys. 97, 1809 (1992), and references therein]. The temperature dependence of 1/2 is predicted to be T(0.44±0.10), in agreement with the experiments of Heymann, Hippler, and Troe [J. Chem. Phys. 80, 1853 (1984)]. Toluene is found to have no net angular-momentum (rotational-energy) transfer to helium bath gas, although 1/2 has a temperature dependence of T(0.31±0.07). Re-evaluation of earlier calculations [``Paper I:'' Lim, J. Chem. Phys. 100, 7385 (1994)] found that rotational energy transfer could be induced by increasing the mass of the collider, or by increasing the strength of the intermolecular interaction: in these cases, angular-momentum transfer depended on the initial excitation energy. In all cases, the final rotational distributions remained Boltzmann.

  12. Proposed heat transfer model for the gas-liquid heat transfer effects observed in the Stanford Research Institute scaled tests. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Corradini, M; Sonin, A A; Todreas, N

    1976-12-01

    In 1971-72, the Stanford Research Institute conducted a series of scaled experiments which simulated a sodium-vapor expansion in a hypothetical core disruptive accident (HCDA) for the Fast Flux Test Facility. A non-condensible explosive source was used to model the pressure-volume expansion characteristics of sodium vapor as predicted by computer code calculations. Rigid piston-cylinder experiments (/sup 1///sub 10/ and /sup 1///sub 30/ scale) were undertaken to determine these expansion characteristics. The results showed that the pressure-volume characteristics depend significantly on the presence of water in the cylinder reducing the work output by about 50 percent when a sufficient water depth was present. The study presented proposes that the mechanism of heat transfer between the water and high temperature gas was due to area enhancement by Taylor instabilities at the gas-liquid interface. A simple heat transfer model is proposed which describes this energy transport process and agrees well with the experimental data from both scaled experiments. The consequences of this analysis suggest that an estimate of the heat transfer to the cold slug during a full-scale HCDA due to sodium vapor expansion and the accompanying reduction in mechanical work energy warrants further investigation. The implication of this analysis is that for either sodium or fuel vapor expansion in an HCDA, there is an inherent heat transfer mechanism which significantly reduces the work output of the expanding bubble.

  13. Local overall volumetric gas-liquid mass transfer coefficients in gas-liquid-solid reversed flow jet loop bioreactor with a non-Newtonian fluid.

    Science.gov (United States)

    Jianping; Ping; Lin; Yunlin

    2000-07-01

    The local overall volumetric gas-liquid mass transfer coefficients at the specified point in a gas-liquid-solid three-phase reversed flow jet loop bioreactor (JLB) with a non-Newtonian fluid was experimentally investigated by a transient gassing-in method. The effects of liquid jet flow rate, gas jet flow rate, particle density, particle diameter, solids loading, nozzle diameter and CMC concentration on the local overall volumetric gas-liquid mass transfer coefficient (K(L)a) profiles were discussed. It was observed that local overall K(L)a profiles in the three-phase reversed flow JLB with non-Newtonian fluid increased with the increase of gas jet flow rate, liquid jet flow rate, particle density and particle diameter, but decreased with the increase of the nozzle diameter and CMC concentration. The presence of solids at a low concentration increased the local overall K(L)a profiles, and the optimum of solids loading for a maximum profile of the local overall K(L)a was found to be 0.18x10(-3)m(3) corresponding to a solids volume fraction, varepsilon(S)=2.8%.

  14. A Mathematical Model of Membrane Gas Separation with Energy Transfer by Molecules of Gas Flowing in a Channel to Molecules Penetrating this Channel from the Adjacent Channel

    Directory of Open Access Journals (Sweden)

    Szwast Maciej

    2015-06-01

    Full Text Available The paper presents the mathematical modelling of selected isothermal separation processes of gaseous mixtures, taking place in plants using membranes, in particular nonporous polymer membranes. The modelling concerns membrane modules consisting of two channels - the feeding and the permeate channels. Different shapes of the channels cross-section were taken into account. Consideration was given to co-current and counter-current flows, for feeding and permeate streams, respectively, flowing together with the inert gas receiving permeate. In the proposed mathematical model it was considered that pressure of gas changes along the length of flow channels was the result of both - the drop of pressure connected with flow resistance, and energy transfer by molecules of gas flowing in a given channel to molecules which penetrate this channel from the adjacent channel. The literature on membrane technology takes into account only the drop of pressure connected with flow resistance. Consideration given to energy transfer by molecules of gas flowing in a given channel to molecules which penetrate this channel from the adjacent channel constitute the essential novelty in the current study. The paper also presents results of calculations obtained by means of a computer program which used equations of the derived model. Physicochemical data concerning separation of the CO2/CH4 mixture with He as the sweep gas and data concerning properties of the membrane made of PDMS were assumed for calculations.

  15. A Lattice Gas Automata Model for the Coupled Heat Transfer and Chemical Reaction of Gas Flow Around and Through a Porous Circular Cylinder

    Directory of Open Access Journals (Sweden)

    Hongsheng Chen

    2015-12-01

    Full Text Available Coupled heat transfer and chemical reaction of fluid flow in complex boundaries are explored by introducing two additional properties, i.e. particle type and energy state into the Lattice gas automata (LGA Frisch–Hasslacher–Pomeau (FHP-II model. A mix-redistribute of energy and type of particles is also applied on top of collision rules to ensure randomness while maintaining the conservation of mass, momentum and energy. Simulations of heat transfer and heterogeneous reaction of gas flow passing a circular porous cylinder in a channel are presented. The effects of porosity of cylinder, gas inlet velocity, and reaction probability on the reaction process are further analyzed with respect to the characteristics of solid morphology, product concentration, and temperature profile. Numerical results indicate that the reaction rate increases with increasing reaction probability as well as gas inlet velocity. Cylinders with a higher value of porosity and more homogeneous structure also react with gas particles faster. These results agree well with the basic theories of gas–solid reactions, indicating the present model provides a method for describing gas–solid reactions in complex boundaries at mesoscopic level.

  16. Detection of nerve agents using proton transfer reaction mass spectrometry with ammonia as reagent gas.

    Science.gov (United States)

    Ringer, Joachim M

    2013-01-01

    The chemical warfare agents (CWA) Sarin, Soman, Cyclosarin and Tabun were characterised by proton transfer mass spectrometry (PTRMS). It was found that PTRMS is a suitable technique to detect nerve agents highly sensitively, highly selectively and in near real-time. Methods were found to suppress molecule fragmentation which is significant under PTRMS hollow cathode ionisation conditions. In this context, the drift voltage (as one of the most important system parameters) was varied and ammonia was introduced as an additional chemical reagent gas. Auxiliary chemicals such as ammonia affect ionisation processes and are quite common in context with detectors for CWAs based on ion mobility spectrometry (IMS). With both, variation of drift voltage and ammonia as the reagent gas, fragmentation can be suppressed effectively. Suppression of fragmentation is crucial particularly concerning the implementation of an algorithm for automated agent identification in field applications. On the other hand, appearance of particular fragments might deliver additional information. Degradation and rearrangement products of nerve agents are not distinctive for the particular agent but for the chemical class they belong to. It was found that switching between ammonia doped and ordinary water ionisation chemistry can easily be performed within a few seconds. Making use of this effect it is possible to switch between fragment and molecular ion peak spectra. Thus, targeted fragmentation can be used to confirm identification based only on single peak detection. PTRMS turned out to be a promising technique for future CWA detectors. In terms of sensitivity, response time and selectivity (or confidence of identification, respectively) PTRMS performs as a bridging technique between IMS and GC-MS.

  17. Thermal-Flow Code for Modeling Gas Dynamics and Heat Transfer in Space Shuttle Solid Rocket Motor Joints

    Science.gov (United States)

    Wang, Qunzhen; Mathias, Edward C.; Heman, Joe R.; Smith, Cory W.

    2000-01-01

    A new, thermal-flow simulation code, called SFLOW. has been developed to model the gas dynamics, heat transfer, as well as O-ring and flow path erosion inside the space shuttle solid rocket motor joints by combining SINDA/Glo, a commercial thermal analyzer. and SHARPO, a general-purpose CFD code developed at Thiokol Propulsion. SHARP was modified so that friction, heat transfer, mass addition, as well as minor losses in one-dimensional flow can be taken into account. The pressure, temperature and velocity of the combustion gas in the leak paths are calculated in SHARP by solving the time-dependent Navier-Stokes equations while the heat conduction in the solid is modeled by SINDA/G. The two codes are coupled by the heat flux at the solid-gas interface. A few test cases are presented and the results from SFLOW agree very well with the exact solutions or experimental data. These cases include Fanno flow where friction is important, Rayleigh flow where heat transfer between gas and solid is important, flow with mass addition due to the erosion of the solid wall, a transient volume venting process, as well as some transient one-dimensional flows with analytical solutions. In addition, SFLOW is applied to model the RSRM nozzle joint 4 subscale hot-flow tests and the predicted pressures, temperatures (both gas and solid), and O-ring erosions agree well with the experimental data. It was also found that the heat transfer between gas and solid has a major effect on the pressures and temperatures of the fill bottles in the RSRM nozzle joint 4 configuration No. 8 test.

  18. Large eddy simulation for predicting turbulent heat transfer in gas turbines.

    Science.gov (United States)

    Tafti, Danesh K; He, Long; Nagendra, K

    2014-08-13

    Blade cooling technology will play a critical role in the next generation of propulsion and power generation gas turbines. Accurate prediction of blade metal temperature can avoid the use of excessive compressed bypass air and allow higher turbine inlet temperature, increasing fuel efficiency and decreasing emissions. Large eddy simulation (LES) has been established to predict heat transfer coefficients with good accuracy under various non-canonical flows, but is still limited to relatively simple geometries and low Reynolds numbers. It is envisioned that the projected increase in computational power combined with a drop in price-to-performance ratio will make system-level simulations using LES in complex blade geometries at engine conditions accessible to the design process in the coming one to two decades. In making this possible, two key challenges are addressed in this paper: working with complex intricate blade geometries and simulating high-Reynolds-number (Re) flows. It is proposed to use the immersed boundary method (IBM) combined with LES wall functions. A ribbed duct at Re=20 000 is simulated using the IBM, and a two-pass ribbed duct is simulated at Re=100 000 with and without rotation (rotation number Ro=0.2) using LES with wall functions. The results validate that the IBM is a viable alternative to body-conforming grids and that LES with wall functions reproduces experimental results at a much lower computational cost.

  19. Effect of Non-condensable gas on Solutal Marangoni Condensation Heat Transfer Characteristics for Water-Ethanol Vapor Mixture

    Science.gov (United States)

    Wang, Shixue; Utaka, Yoshio

    The condensation heat transfer characteristic curves for ternary vapor mixture of water, ethanol and air (or nitrogen) under the ethanol mass fraction of 0.01, 0.07, 0.25, 0.45 and relatively low concentrations of air (or nitrogen) were measured.The effect of air (or nitrogen) as a non-condensable gas on several different domains in the Marangoni condensation characteristic curves was discussed. It was shown that the effect of non-condensable gas in the domains controlled by the diffusion resistance and the filmwise condensation was not notable but in the domain dominated by the condensate resistance of dropwise mode was remarkable. Moreover, the variations of the several characteristic points representing the characteristic curves caused by the change in non-condensable gas concentration were discussed. The deteriorations of the maximum heat transfer coefficient and the maximum heat flux for low ethanol concentration and low concentration of non-condensable gas, in which the excellent heat transfer characteristics were exhibited, were more remarkable.

  20. Analysis of Fluid Flow and Heat Transfer Model for the Pebble Bed High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    S. Yamoah

    2012-06-01

    Full Text Available The pebble bed type high temperature gas cooled nuclear reactor is a promising option for next generation reactor technology and has the potential to provide high efficiency and cost effective electricity generation. The reactor unit heat transfer poses a challenge due to the complexity associated with the thermalflow design. Therefore to reliably simulate the flow and heat transport of the pebble bed modular reactor necessitates a heat transfer model that deals with radiation as well as thermal convection and conduction. In this study, a model with the capability to simulate fluid flow and heat transfer in the pebble bed modular reactor core has been developed. The developed model was implemented on a personal computer using FORTRAN 95 programming language. Several important fluid flow and heat transfer parameters have been examined: including the pressure drop over the reactor core, the heat transfer coefficient, the Nusselt number and the effective thermal conductivity of the fuel pebbles. Results obtained from the simulation experiments show a uniform pressure in the radial direction for a core to fuel element diameter (D/d ratio>20 and the heat transfer coefficient increases with increasing temperature and coolant mass flow rate. The model can adequately account for the flow and heat transfer phenomenon and the loss of pressure through friction in the pebble bed type high temperature nuclear reactor.

  1. Evaluation of radiation heat transfer in porous medial: Application for a pebble bed modular reactor cooled by CO2 gas

    Directory of Open Access Journals (Sweden)

    Sidi-Ali Kamel

    2013-01-01

    Full Text Available This work analyses the contribution of radiation heat transfer in the cooling of a pebble bed modular reactor. The mathematical model, developed for a porous medium, is based on a set of equations applied to an annular geometry. Previous major works dealing with the subject have considered the forced convection mode and often did not take into account the radiation heat transfer. In this work, only free convection and radiation heat transfer are considered. This can occur during the removal of residual heat after shutdown or during an emergency situation. In order to derive the governing equations of radiation heat transfer, a steady-state in an isotropic and emissive porous medium (CO2 is considered. The obtained system of equations is written in a dimensionless form and then solved. In order to evaluate the effect of radiation heat transfer on the total heat removed, an analytical method for solving the system of equations is used. The results allow quantifying both radiation and free convection heat transfer. For the studied situation, they show that, in a pebble bed modular reactor, more than 70% of heat is removed by radiation heat transfer when CO2 is used as the coolant gas.

  2. A Computational Fluid Dynamic and Heat Transfer Model for Gaseous Core and Gas Cooled Space Power and Propulsion Reactors

    Science.gov (United States)

    Anghaie, S.; Chen, G.

    1996-01-01

    A computational model based on the axisymmetric, thin-layer Navier-Stokes equations is developed to predict the convective, radiation and conductive heat transfer in high temperature space nuclear reactors. An implicit-explicit, finite volume, MacCormack method in conjunction with the Gauss-Seidel line iteration procedure is utilized to solve the thermal and fluid governing equations. Simulation of coolant and propellant flows in these reactors involves the subsonic and supersonic flows of hydrogen, helium and uranium tetrafluoride under variable boundary conditions. An enthalpy-rebalancing scheme is developed and implemented to enhance and accelerate the rate of convergence when a wall heat flux boundary condition is used. The model also incorporated the Baldwin and Lomax two-layer algebraic turbulence scheme for the calculation of the turbulent kinetic energy and eddy diffusivity of energy. The Rosseland diffusion approximation is used to simulate the radiative energy transfer in the optically thick environment of gas core reactors. The computational model is benchmarked with experimental data on flow separation angle and drag force acting on a suspended sphere in a cylindrical tube. The heat transfer is validated by comparing the computed results with the standard heat transfer correlations predictions. The model is used to simulate flow and heat transfer under a variety of design conditions. The effect of internal heat generation on the heat transfer in the gas core reactors is examined for a variety of power densities, 100 W/cc, 500 W/cc and 1000 W/cc. The maximum temperature, corresponding with the heat generation rates, are 2150 K, 2750 K and 3550 K, respectively. This analysis shows that the maximum temperature is strongly dependent on the value of heat generation rate. It also indicates that a heat generation rate higher than 1000 W/cc is necessary to maintain the gas temperature at about 3500 K, which is typical design temperature required to achieve high

  3. The effect of microbubbles on gas-liquid mass transfer coefficient and degradation rate of COD in wastewater treatment.

    Science.gov (United States)

    Yao, Kangning; Chi, Yong; Wang, Fei; Yan, Jianhua; Ni, Mingjiang; Cen, Kefa

    2016-01-01

    A commonly used aeration device at present has the disadvantages of low mass transfer rate because the generated bubbles are several millimeters in diameter which are much bigger than microbubbles. Therefore, the effect of a microbubble on gas-liquid mass transfer and wastewater treatment process was investigated. To evaluate the effect of each bubble type, the volumetric mass transfer coefficients for microbubbles and conventional bubbles were determined. The volumetric mass transfer coefficient was 0.02905 s(-1) and 0.02191 s(-1) at a gas flow rate of 0.67 L min(-1) in tap water for microbubbles and conventional bubbles, respectively. The degradation rate of simulated municipal wastewater was also investigated, using aerobic activated sludge and ozone. Compared with the conventional bubble generator, the chemical oxygen demand (COD) removal rate was 2.04, 5.9, 3.26 times higher than those of the conventional bubble contactor at the same initial COD concentration of COD 200 mg L(-1), 400 mg L(-1), and 600 mg L(-1), while aerobic activated sludge was used. For the ozonation process, the rate of COD removal using microbubble generator was 2.38, 2.51, 2.89 times of those of the conventional bubble generator. Based on the results, the effect of initial COD concentration on the specific COD degradation rate were discussed in different systems. Thus, the results revealed that microbubbles could enhance mass transfer in wastewater treatment and be an effective method to improve the degradation of wastewater.

  4. TECHNOLOGY TRANSFER TO U.S. INDEPENDENT OIL AND NATURAL GAS PRODUCERS

    Energy Technology Data Exchange (ETDEWEB)

    Donald F. Duttlinger; E. Lance Cole

    2003-12-15

    The Petroleum Technology Transfer Council (PTTC) continued pursuing its mission of assisting U.S. independent oil and gas producers to make timely, informed technology decisions. Functioning as a cohesive national organization, PTTC has active grassroots programs through its 10 Regional Lead Organizations (RLOs) and 3 Satellite Offices that encompass all of the oil- and natural gas-producing regions in the U.S. Active volunteer leadership from the Board and regional Producer Advisory Groups keeps activities focused on producer's needs. Technical expertise and personal networks of national and regional staff enable PTTC to deliver focused, technology-related information in a manner that is cost and time effective for independents. The organization effectively combines federal funding through the Department of Energy's (DOE) Office of Fossil Energy with matching state and industry funding, forming a unique partnership. This final report summarizes PTTC's accomplishments. In this final fiscal year of the contract, activities exceeded prior annual activity levels by significant percentages. Strategic planning implemented during the year is focusing PTTC's attention on changes that will bear fruit in the future. Networking and connections are increasing PTTC's sphere of influence with both producers and the service sector. PTTC's reputation for unbiased bottom-line information stimulates cooperative ventures. In FY03 PTTC's regions held 169 workshops, drawing 8,616 attendees. There were nearly 25,000 reported contacts. This represents a 38% increase in attendance and 34% increase in contacts as compared to FY02 activity. Repeat attendance at regional workshops, a measure of customer satisfaction and value received, remained strong at 50%. 39% of participants in regional workshops respond ''Yes'' on feedback forms when asked if they are applying technologies based on knowledge gained through PTTC. This feedback

  5. Secondary flow and heat transfer control in gas turbine inlet nozzle guide vanes

    Science.gov (United States)

    Burd, Steven Wayne

    1998-12-01

    Endwall heat transfer is a very serious problem in the inlet nozzle guide vane region of gas turbine engines. To resolve heat transfer concerns and provide the desired thermal protection, modern cooling flows for the vane endwalls tend to be excessive leading to lossy and inefficient designs. Coolant introduction is further complicated by the flow patterns along vane endwall surfaces. They are three-dimensional and dominated by strong, complex secondary flows. To achieve performance goals for next-generation engines, more aerodynamically efficient and advanced cooling concepts, including combustor bleed cooling, must be investigated. To this end, the overall performance characteristics of several combustor bleed flow designs are assessed in this experimental study. In particular, their contributions toward secondary flow control and component cooling are documented. Testing is performed in a large-scale, guide vane simulator comprised of three airfoils encased between one contoured and one flat endwall. Core flow is supplied to this simulator at an inlet chord Reynolds number of 350,000 and turbulence intensity of 9.5%. Combustor bleed cooling flow is injected through the contoured endwall via inclined slots. The slots vary in cross-sectional area, have equivalent slot widths, and are positioned with their leeward edges 10% of the axial chord ahead of the airfoil leading edges. Measurements with hot-wire anemometry characterize the inlet and exit flow fields of the cascade. Total and static pressure measurements document aerodynamic performance. Thermocouple measurements detail thermal fields and permit evaluation of surface adiabatic effectiveness. To elucidate the effects of bleed injection, data are compared to an experiment taken without bleed. The influence of bleed mass flow rate and slot geometry on the aerodynamic losses and thermal protection arc given. This study suggests that such combustor bleed flow cooling offers significant thermal protection without

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

    Institute of Scientific and Technical Information of China (English)

    LU Tao; WANG Kuisheng

    2009-01-01

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

  7. Catse Analysis of Damage Reason of Gas Heat Transfer and Solutions%煤气换热器损坏原因分析及解决方案

    Institute of Scientific and Technical Information of China (English)

    郭红永; 张宁; 王三多; 刘常鹏

    2011-01-01

    针对鞍钢1700 ASP生产线加热炉煤气换热器损坏问题,从煤气换热器本身构造及外部环境进行系统分析,并采用化学检测等方法确定了换热器损坏的直接原因,具体为煤气管道中的水进入换热器内造成温度应力、内部煤气分流不均、空气换热器换热效果不佳等,并提出了改进煤气换热器结构、加大煤气管道排水能力、增加空气换热器换热而积的策略.%Aiming at the gas heat transfer damage problem of heating furnace in Ansteel 1700 ASP production Line, systemic analysis was done from the gas heat transfer itself structure and external environment, and the direct damage reasons were determined by using chemical testing methods, which included the temperature stress caused by the water of gas pipes into the heat transfer, the uneven distributed internal gas, the bad heat transfer effect of the air transfer, and so on. The treatment strategies were promoted such as improving the structure of gas heat transfer, increasing the gas pipes drainage efforts, and increasing the heat transfer area of air heat transfer.

  8. Heat transfer in supersonic dusty-gas flow past a blunt body with inertial particle deposition effect

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Heat transfer in a supersonic steady flow of a dilute dusty-gas past a sphere is considered at large and moderate Reynolds numbers. For the regime of inertial particle deposition on the frontal surface of the body, a parametric study of maximum increase in the particle-induced heat flux at the stagnation point is performed over a wide range of the Reynolds number, the particle inertia parameter, the ratio of the phase specific heats, and the body surface temperature.

  9. Computer-based sensing and visualizing of metal transfer mode in gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    Chen Maoai; Wu Chuansong; Lü Yunfei

    2008-01-01

    Using Xenon lamp lights to overcome the strong interference from the welding arc, a computer-based system is developed to sense and visualize the metal transfer in GMAW. This system combines through-the-arc sensing of the welding current and arc voltage with high speed imaging of the metal transfer. It can simultaneously display the metal transfer processes and waveforms of electrical welding parameters in real-time The metal transfer videos and waveforms of electrical welding parameters can be recorded. Metal transfers under various welding conditions have been investigated with the system developed.

  10. Experimental evaluation of enthalpy efficiency and gas-phase contaminant transfer in an enthalpy recovery unit with polymer membrane foils

    DEFF Research Database (Denmark)

    Nie, Jinzhe; Yang, Jianrong; Fang, Lei;

    2015-01-01

    Experimental studies were conducted in a laboratory setting to investigate the enthalpy efficiency and gas-phase contaminant transfer in a polymer membrane enthalpy recovery unit. One commercially available polymer membrane enthalpy recovery unit was used as a reference unit. Simulated indoor air...... and outdoor air by twin chambers was connected to the unit. Three chemical gases were dosed to the indoor exhaust air to mimic indoor air contaminants. Based on the measurements of temperature, humidity ratio, and contaminant concentrations of the indoor exhaust air and outdoor air supply upstream...... and downstream of the unit, the temperature efficiencies, humidity efficiencies, enthalpy efficiencies, and contaminant transfer ratios were calculated. The results showed that over 60% of enthalpy recovery efficiency could be achieved and that the contaminant transfer ratios were in the range of 5.4% to 9...

  11. Modelling of gas-liquid reactors - stability and dynamic behaviour of gas-liquid mass transfer accompanied by irreversible reaction

    NARCIS (Netherlands)

    Elk, E.P. van; Borman, P.C.; Kuipers, J.A.M.; Versteeg, G.F.

    1999-01-01

    The dynamic behaviour and stability of single-phase reacting systems has been investigated thoroughly in the past and design rules for stable operation are available from literature. The dynamic behaviour of gas-liquid processes is considerably more complex and has received relatively little attenti

  12. Mechanism of kinetic energy transfer in homogeneous bidisperse gas-solid flow and its implications for segregation

    Science.gov (United States)

    Mehrabadi, Mohammad; Subramaniam, Shankar

    2017-02-01

    Most gas-solid flows encountered in nature and industrial applications are polydisperse, and the segregation or mixing of particle classes in polydisperse gas-solid flows is a phenomenon of great practical importance. A statistically homogeneous gas-solid flow with a bidisperse distribution (in size or density) of particles is a canonical representation of polydisperse flows. A key feature that distinguishes the bidisperse flow from its monodisperse counterpart is the exchange of momentum and kinetic energy between the particle classes due to collisions, which are important for applications outside the very dilute regime. The average exchange of linear momentum between particle classes due to collisions occurs through the particle-particle drag term. The conservation equations for average momentum corresponding to each particle class can be used to deduce the average slip velocity between the particle size and density classes, which is the signature of particle segregation. In this canonical problem, the steady value of particle mean slip velocity results from a balance between three terms, each in turn involving the body force or the mean fluid pressure gradient, the gas-particle drag, and the particle-particle drag. The particle-particle drag depends on the particle velocity fluctuations in each class [Louge, M. Y. et al., "The role of particle collisions in pneumatic transport," J. Fluid Mech. 231, 345-359 (1991)], thereby coupling the mean and second-moment equations. For monodisperse gas-solid flows the transfer of kinetic energy from the mean to second-moment equations was explained by Subramaniam and co-workers who proposed the conservation of interphase turbulent kinetic energy transfer principle [Xu, Y. and Subramaniam, S., "Consistent modeling of interphase turbulent kinetic energy transfer in particle-laden turbulent flows," Phys. Fluids 19(8), 085101 (2007)], and this was subsequently verified by particle-resolved direct numerical simulation [Mehrabadi

  13. Numerical Simulation of Heat Transfer in a Gas Solid Crossflow Moving Packed Bed Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    Anyuan Liu; Shi Liu; Yufeng Duan; Zhonggang Pan

    2001-01-01

    The mechanism of heat transfer in a crossfiow moving packed bed heat transfer exchanger is analyzed and a two dimensional heat transfer mathematical model has been developed based on the two fluid model (TFM) approach, in which both phases are considered to be continuous and fully interpenetrating. This model is solved by means of numerical method and the results are approximately in agreement with the experimental ones.

  14. Mass transfer phenomena of gaseous hydrocarbons and nitrogen dioxide across gas-inorganic pigments boundaries

    Science.gov (United States)

    Birbatakou, S.; Pagopoulou, I.; Kalantzopoulos, A.; Roubani-Kalantzopoulou, F.

    1998-11-01

    Reversed-flow gas chromatography was used to study the kinetics of the action of five hydrocarbons namely, ethane, ethene, ethyne, propene and butene and of the nitrogen dioxide, on three known and widely used pigments, the white one TiO2, and the yellows CdS and PbCrO4. The calculation of kinetic parameters and mass transfer coefficients is based on an experimental adsorption isotherm. All these calculations are based on a non linear adsorption isotherm model as it is well accepted that the linear one is inadequate for inorganic substances like these mentioned in this work. The inadequacy is mainly attributed to the non-uniformity of the solid surface. Five physicochemical parameters have been obtained for each of the twenty heterogeneous reactions studied. With these systematic experiments under conditions which are similar to the atmospheric ones, an extrapolation of the results obtained to “real" atmospheres with a high degree of confidence is possible. Some of the calculations were based on the linear model for comparison. La cinétique de la réaction de cinq hydrocarbures (éthane, éthylène, acétylène, propène, boutène) et du dioxyde d'azote avec trois pigments (le blanc de TiO2 et les jaunes de CdS et PbCrO4) a été étudiée par chromatographie en phase gazeuse a flux inversé. Le calcul des paramètres cinétiques et des coefficients de transfert de masse a été effectué à partir des isothermes d'adsorption expérimentales en faisant l'hypothèse d`un modèle d'adsorption non-linéaire, qui résulte de la non-uniformité de la surface. Cinq paramètres physico-chimiques ont été obténus pour chacune des vingt réaction hétérogènes étudiées. À partir de ces résultats obténus dans des conditions similaires aux conditions atmosphériques, l'extrapolation à des atmosphères réelles paraît possible avec une bonne confiance. Quelques calculs ont été effectués avec un modèle linéaire pour comparaison.

  15. Simultaneous measurements of air-sea gas transfer velocity and near surface turbulence at low to moderate winds (Invited)

    Science.gov (United States)

    Wang, B.; Liao, Q.; Fillingham, J. H.; Bootsma, H. A.

    2013-12-01

    Parameterization of air-sea gas transfer velocity was routinely made with wind speed. Near surface turbulent dissipation rate has been shown to have better correlation with the gas transfer velocity in a variety of aquatic environments (i.e., the small eddy model) while wind speed is low to moderate. Wind speed model may underestimate gas transfer velocity at low to moderate winds when the near surface turbulence is produced by other environmental forcing. We performed a series of field experiments to measure the CO2 transfer velocity, and the statistics of turbulence immediately below the air-water interface using a novel floating PIV and chamber system. The small eddy model was evaluated and the model coefficient was found to be a non-constant, and it varies with the local turbulent level (figure 1). Measure results also suggested an appropriate scaling of the vertical dissipation profile immediately below the interface under non-breaking conditions, which can be parameterized by the wind shear, wave height and wave age (figure 2). Figure 1. Relation between the coefficient of the small eddy model and dissipation rate. The data also include Chu & Jirka (2003) and Vachon et al. (2010). The solid regression line: α = 0.188log(ɛ)+1.158 Figure 2. Non-dimensional dissipation profiles. Symbols: measured data with the floating PIV. Solid line: regression of measured data with a -0.79 decaying rate. Dash line with -2 slope: Terray et al. (1996) relation. Dash line with two layer structure: Siddiqui & Loewen (2007) relation.

  16. Gas hold-up and oxygen mass transfer in three pneumatic bioreactors operating with sugarcane bagasse suspensions.

    Science.gov (United States)

    Esperança, M N; Cunha, F M; Cerri, M O; Zangirolami, T C; Farinas, C S; Badino, A C

    2014-05-01

    Sugarcane bagasse is a low-cost and abundant by-product generated by the bioethanol industry, and is a potential substrate for cellulolytic enzyme production. The aim of this work was to evaluate the effects of air flow rate (QAIR), solids loading (%S), sugarcane bagasse type, and particle size on the gas hold-up (εG) and volumetric oxygen transfer coefficient (kLa) in three different pneumatic bioreactors, using response surface methodology. Concentric tube airlift (CTA), split-cylinder airlift (SCA), and bubble column (BC) bioreactor types were tested. QAIR and %S affected oxygen mass transfer positively and negatively, respectively, while sugarcane bagasse type and particle size (within the range studied) did not influence kLa. Using large particles of untreated sugarcane bagasse, the loop-type bioreactors (CTA and SCA) exhibited higher mass transfer, compared to the BC reactor. At higher %S, SCA presented a higher kLa value (0.0448 s−1) than CTA, and the best operational conditions in terms of oxygen mass transfer were achieved for %S 27.0 L min−1. These results demonstrated that pneumatic bioreactors can provide elevated oxygen transfer in the presence of vegetal biomass, making them an excellent option for use in three-phase systems for cellulolytic enzyme production by filamentous fungi.

  17. Simulation and Optimization of Strengthening the Gas-Liquid Mass Transfer Structure in Tray Column

    Directory of Open Access Journals (Sweden)

    Duan Jihai

    2015-01-01

    Full Text Available This paper presented the analysis of the effect of the mesh layers, installation height and opening rate on gas-liquid two-phase flow field by numerical simulation, which based on Euler-Euler model and identified the best liquid-gas ratio. The simulation results showed that: when the installation height of the square mesh was 25 mm and opening rate was 55.7%, the gas holdup distribution in the upper part of the mesh became higher and improved the liquid velocity distribution. Meanwhile, the gas-liquid distribution on trays was more uniform.

  18. Convective Heat Transfer in Internal Gas Flows with Temperature-Dependent Properties.

    Science.gov (United States)

    1982-06-30

    effects of variable properties have been provided by Petukhov [1970],specifically for turbulent flow in circular tubes.and by Leontiev o for the...243-249. Leontiev , A. I., 1966. Heat and mass transfer in turbulent boundary layers, Adv. Heat Transfer, 3, pp. 33-100. Leung, E. Y., V. M. Kays and W

  19. ENHANCEMENT OF GAS TO WATER MASS-TRANSFER RATES BY A DISPERSED ORGANIC-PHASE

    NARCIS (Netherlands)

    VANEDE, CJ; VANHOUTEN, R; BEENACKERS, AACM

    1995-01-01

    Experimental data are presented on the enhancement of oxygen mass transfer into an aqueous sulphite solution in a stirred cell, due to the presence of a dispersed liquid octene phase. The observed enhancement factors can be described with a new mass transfer theory, called the Film Variable Hold-up

  20. Determination of the gas-to-membrane mass transfer coefficient in a catalytic membrane reactor

    NARCIS (Netherlands)

    Veldsink, J.W.; Versteeg, G.F.; Swaaij, W.P.M. van

    1995-01-01

    A novel method to determine the external mass transfer coefficient in catalytic membrane reactors (Sloot et al., 1992a, b) was presented in this study. In a catalytically active membrane reactor, in which a very fast reaction occurs, the external transfer coefficient can conveniently be measured by

  1. Gas Temperature and Radiative Heat Transfer in Oxy-fuel Flames

    DEFF Research Database (Denmark)

    Bäckström, Daniel; Johansson, Robert; Andersson, Klas

    temperature than the suction pyrometer in the low velocity regions of the furnace, a difference which is likely to be an effect of the purge gas added in the optical probe. The measured temperature fluctuations were evaluated by modeling of the gas radiation. The influence from the measured fluctuations...

  2. A Computationally-Efficient Kinetic Approach for Gas/Particle Mass Transfer Treatments: Development, Testing, and 3-D Application

    Science.gov (United States)

    Hu, X.; Zhang, Y.

    2007-05-01

    The Weather Research and Forecast/Chemistry Model (WRF/Chem) that simulates chemistry simultaneously with meteorology has recently been developed for real-time forecasting by the U.S. National Center for Atmospheric Research (NCAR) and National Oceanic & Atmospheric Administration (NOAA). As one of the six air quality models, WRF/Chem with a modal aerosol module has been applied for ozone and PM2.5 ensemble forecasts over eastern North America as part of the 2004 New England Air Quality Study (NEAQS) program (NEAQS-2004). Significant differences exist in the partitioning of volatile species (e.g., ammonium and nitrate) simulated by the six models. Model biases are partially attributed to the equilibrium assumption used in the gas/particles mass transfer approach in some models. Development of a more accurate, yet computationally- efficient gas/particle mass transfer approach for three-dimensional (3-D) applications, in particular, real-time forecasting, is therefore warranted. Model of Aerosol Dynamics, Reaction, Ionization, and Dissolution (MADRID) has been implemented into WRF/Chem (referred to as WRF/Chem-MADRID). WRF/Chem-MADRID offers three gas/particle partitioning treatments: equilibrium, kinetic, and hybrid approaches. The equilibrium approach is computationally-efficient and commonly used in 3-D air quality models but less accurate under certain conditions (e.g., in the presence of coarse, reactive particles such as PM containing sea-salts in the coastal areas). The kinetic approach is accurate but computationally-expensive, limiting its 3-D applications. The hybrid approach attempts to provide a compromise between merits and drawbacks of the two approaches by treating fine PM (typically MADRID has recently been developed for 3-D applications based on an Analytical Predictor of Condensation (referred to as kinetic/APC). In this study, WRF/Chem-MADRID with the kinetic/APC approach will be further evaluated along with the equilibrium and hybrid approaches

  3. Hydrodynamics and heat transfer of gas-solid two-phase mixtures flowing through packed beds-a review

    Institute of Scientific and Technical Information of China (English)

    Yulong Ding; Yurong He; Ngoc Thang Cong; Wei Yang; Haisheng Chen

    2008-01-01

    Flow of a gas-solid two-phase mixture through a packed bed is relevant to a number of industrial processes such as heat recovery and filtration of dusty flue gases,iron making in shaft reactors,gas purification,and sorption enhanced reaction processes.In spite of the industrial relevance,little work has been reported in the literature.The limited amount of research work has mainly addressed the macroscopic hydrodynamics in terms of pressure drop and solids hold-ups at the ambient temperature.Very little is done,until fairly recent,on solids motion at the single particle level,hydrodynamics at elevated temperatures and heat transfer.This paper reviews the recent development in the field including both the hydrodynamics and heat transfer of gas-solid two-phase mixtures flowing through packed beds,which is believed to represent the state-of-the-art in the field.The review is not aimed to be exhaustive but rather focused on our own work carried out over the past few years in the Institute of Particle Science & Engineering at the University of Leeds.And some of our results are compared with that of other groups.

  4. Gas-liquid transfer data used to analyze hydrophobic hydration and find the nature of the Kauzmann-Tanford hydrophobic factor.

    Science.gov (United States)

    Baldwin, Robert L

    2012-05-08

    Hydrophobic free energy for protein folding is currently measured by liquid-liquid transfer, based on an analogy between the folding process and the transfer of a nonpolar solute from water into a reference solvent. The second part of the analogy (transfer into a nonaqueous solvent) is dubious and has been justified by arguing that transfer out of water probably contributes the major part of the free energy change. This assumption is wrong: transfer out of water contributes no more than half the total, often less. Liquid-liquid transfer of the solute from water to liquid alkane is written here as the sum of 2 gas-liquid transfers: (i) out of water into vapor, and (ii) from vapor into liquid alkane. Both gas-liquid transfers have known free energy values for several alkane solutes. The comparable values of the two different transfer reactions are explained by the values, determined in 1991 for three alkane solutes, of the cavity work and the solute-solvent interaction energy. The transfer free energy is the difference between the positive cavity work and the negative solute-solvent interaction energy. The interaction energy has similar values in water and liquid alkane that are intermediate in magnitude between the cavity work in water and in liquid alkane. These properties explain why the transfer free energy has comparable values (with opposite signs) in the two transfers. The current hydrophobic free energy is puzzling and poorly defined and needs a new definition and method of measurement.

  5. The use of an Ultrasonic ''Transfer reference meter'' to investigate differences of two gas meters in series in fiscal natural gas measurement

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, Volker; Dietz, Toralf; Ehrlich, Andreas; Stoll, Peter; Slawig, Heiko

    2005-07-01

    This paper introduces the use of an Ultrasonic 8 path ''Transfer reference meter'' and a reference meter of another technology to investigate differences as high as 0,8% in a German custody transfer station. This method can be used much more effectively since none of the meters under question needs to be taken out of operation or sent back. Additionally, using the more detailed profile information gained from an 8 path meter it is possible to investigate installation effects and detect sources of the deviations. First results of the investigation of the above mentioned station will be shown and discussed. Possible ways of using transfer reference meters of different technologies and their advantages and drawbacks are also considered. Conclusion: The use of a reference meter section integrating different measuring technologies for diagnosing installation-conditional deviations under operational conditions has proven to be very successful. The combination of metrological experience of the manufacturers, the application-engineering competence of the operator, and the utilization of the diagnostic capabilities of state-of-the-art measuring methods, such as the ultrasonic and the Coriolis measuring technique, allows an in depth study of the behaviour of the measuring section. Taking this as a basis, it is possible to optimise station layouts, reduce the cost for additional high-pressure calibrations, and ensure reliable operation. The plan for the future is to examine the offset between ultrasonic/turbine gas meter and Coriolis gas meter by extended tests. Among other things, the entire package will be tested once again both under high-pressure and low-pressure conditions. At the same time, a statement will be made as to the long-term behaviour of the relative deviations. As an additional intellectual approach, the idea has arisen to examine whether a sole low-pressure calibration and/or water calibration for meters may be sufficient in the future

  6. 吸收过程的界面传质机理%The Mechanism of Interfacial Mass Transfer in Gas Absorption Process

    Institute of Scientific and Technical Information of China (English)

    马友光; 冯惠生; 徐世昌; 余国琮

    2003-01-01

    Based on the method of molecular thermodynamics, the mass transfer mechanism at gas-liquid interface is studied theoretically, and a new mathematical model is proposed. Using laser holographic interference technique, the hydrodynamics and mass transfer characteristics of CO2 absorption are measured. It is shown that the calculated results are in good agreement with the experimental data.

  7. Heat Transfer between Horizontal Finned Tubes and a Gas-Solid Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Grewal, N.S.; Cheung, T.K.; Saxena, S.C.

    1985-04-01

    The heat-transfer coefficients are measured between electrically heated V-thread tubes and square fluidized beds of alumina and silica sand. The effect of particle size, mass fluidizing velocity, V-thread pitch, and tube pitch on the heat transfer rate is investigated. One-dimensional and two-dimensional heat conduction models are developed for determining the temperature distribution in a V-thread fin. The models are used to calculate the corrected heat-transfer coefficients for the finned tubes. A correlation for the fin effectiveness factor is proposed and is found to be reliable to predict its value for finned tubes with geometry and orientation similar to that in the present investigation. The correlation in conjunction with the existing correlatins for the heat-transfer coefficient for smooth tubes is found, in general, to predict the coefficients for finned tubes immersed in a fluidized bed within + or - 25%.

  8. A New Model for Gas Transfer and Storage in a Permeable Volcanic Edifice

    Science.gov (United States)

    Collinson, A. D.; Neuberg, J.

    2011-12-01

    There is a marked contrast between the behaviour of a volcano in an open system compared to one which is closed. It is therefore essential to understand degassing, to appreciate how much gas is lost and where. Previous studies by a variety of scientists have led to the accumulation of data via field evidence from both active and fossil volcanoes (Stasiuk et al., 1996), laboratory experiments (Moore et al., 1994) and conceptual modelling, in which Darcy's law has become increasingly applicable (Eichelberger et al., 1986; Edmonds et al., 2003). Of particular interest for this study, is the effect different permeabilities have on the degree and pattern of the gas flux. A new method has been devised to investigate gas transport and storage in a permeable volcanic edifice. The continuity equation and Darcy's law are amalgamated to derive a partial differential equation which is solved using a finite element method to obtain the gas pressure. The associated pressure gradient is then used within Darcy's law to calculate the gas flux. The properties of the gas are described by the ideal gas law. The strength of this method is that it allows the modelling of two and three dimensional structures both in stationary equilibrium and as a time dependent progression. A geometry is created and the pressure and permeabilites incorporated into the model as boundary and domain conditions respectively. The aim of the model is to investigate how variable permeability and pressure gradients influence the gas flux, for example highly permeable cracks in the dome, or impermeable layers within the volcanic structure. We also use this gas model to complement the model of Neuberg et al. (2006) in which brittle failure of the conduit-wall boundary is used as a trigger mechanism of low-frequency earthquakes. The associated behaviour of the gas in response to the brittle failure is simulated in our model by increasing the permeability through a narrow zone at the boundary between the conduit

  9. EFFECTS OF ALTERNATE ANTIFOAM AGENTS, NOBLE METALS, MIXING SYSTEMS AND MASS TRANSFER ON GAS HOLDUP AND RELEASE FROM NONNEWTONIAN SLURRIES

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, H; Mark Fowley, M; Charles Crawford, C; Michael Restivo, M; Robert Leishear, R

    2007-12-24

    Gas holdup tests performed in a small-scale mechanically-agitated mixing system at the Savannah River National Laboratory (SRNL) were reported in 2006. The tests were for a simulant of waste from the Hanford Tank 241-AZ-101 and featured additions of DOW Corning Q2-3183A Antifoam agent. Results indicated that this antifoam agent (AFA) increased gas holdup in the waste simulant by about a factor of four and, counter intuitively, that the holdup increased as the simulant shear strength decreased (apparent viscosity decreased). These results raised questions about how the AFA might affect gas holdup in Hanford Waste Treatment and Immobilization Plant (WTP) vessels mixed by air sparging and pulse-jet mixers (PJMs). And whether the WTP air supply system being designed would have the capacity to handle a demand for increased airflow to operate the sparger-PJM mixing systems should the AFA increase retention of the radiochemically generated flammable gases in the waste by making the gas bubbles smaller and less mobile, or decrease the size of sparger bubbles making them mix less effectively for a given airflow rate. A new testing program was developed to assess the potential effects of adding the DOW Corning Q2-3183A AFA to WTP waste streams by first confirming the results of the work reported in 2006 by Stewart et al. and then determining if the AFA in fact causes such increased gas holdup in a prototypic sparger-PJM mixing system, or if the increased holdup is just a feature of the small-scale agitation system. Other elements of the new program include evaluating effects other variables could have on gas holdup in systems with AFA additions such as catalysis from trace noble metals in the waste, determining mass transfer coefficients for the AZ-101 waste simulant, and determining whether other AFA compositions such as Dow Corning 1520-US could also increase gas holdup in Hanford waste. This new testing program was split into two investigations, prototypic sparger

  10. Rotational Energy Transfer of N2 Gas Determined Using a New Ab Initio Potential Energy Surface

    Science.gov (United States)

    Huo, Winifred M.; Stallcop, James R.; Partridge, Harry; Langhoff, Stephen R. (Technical Monitor)

    1997-01-01

    Rotational energy transfer between two N2 molecules is a fundamental process of some importance. Exchange is expected to play a role, but its importance is somewhat uncertain. Rotational energy transfer cross sections of N2 also have applications in many other fields including modeling of aerodynamic flows, laser operations, and linewidth analysis in nonintrusive laser diagnostics. A number of N2-N2 rigid rotor potential energy surface (PES) has been reported in the literature.

  11. A novel high-heat transfer low-NO{sub x} natural gas combustion system. Phase 1 final report

    Energy Technology Data Exchange (ETDEWEB)

    Rue, D.M. [Institute of Gas Technology, Des Plaines, IL (United States); Fridman, A. [Univ. of Illinois, Chicago (United States); Viskanta, R. [Purdue Univ. (United States); Neff, D. [Cumbustion Tec, Inc. (United States)

    1997-11-01

    Phase I of the project focused on acquiring the market needs, modeling, design, and test plan information for a novel high-heat transfer low-NO{sub x} natural gas combustion system. All goals and objectives were achieved. The key component of the system is an innovative burner technology which combines high temperature natural gas preheating with soot formation and subsequent soot burnout in the flame, increases the system`s energy efficiency and furnace throughput, while minimizing the furnace air emissions, all without external parasitic systems. Work has included identifying industry`s needs and constraints, modeling the high luminosity burner system, designing the prototype burner for initial laboratory-scale testing, defining the test plan, adapting the burner technology to meet the industry`s needs and constraints, and outlining the Industrial Adoption Plan.

  12. Mass transfer and chemical reaction in gas-liquid-liquid systems

    NARCIS (Netherlands)

    Brilman, Derk Willem Frederik

    1998-01-01

    Gas-liquid-liquid reaction systems may be encountered in several important fields of application as e.g. hydroformylation, alkylation, carboxylation, polymerisation, hydrometallurgy, biochemical processes and fine chemicals manufacturing. However, the reaction engineering aspects of these systems ha

  13. Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties

    Science.gov (United States)

    Doi, Toshiyuki

    2016-09-01

    Transient motion of and heat transfer in a rarefied gas between plane parallel walls with different surface properties are studied based on kinetic theory. It is assumed that one wall is a diffuse reflection boundary and the other wall is a Maxwell-type boundary, and the transient behavior of the gas caused by a sudden heating of one of the walls is studied. The linearized Boltzmann equation for a hard-sphere molecular gas is numerically studied using the modified hybrid scheme of the characteristic coordinate and finite difference methods, to correctly describe the discontinuities in the velocity distribution function. The transient motion of the gas from an early time stage to the final time-independent state is studied over a wide range of the mean free path and the accommodation coefficient of the boundary. Between the two transient flows caused by the heating of the respective walls, the values of the heat flow on the heated wall are different, whereas those on the unheated wall coincide identically. This property, which is a consequence of the symmetric relation of the linearized Boltzmann equation, is numerically confirmed over a wide range of the mean free path. The long time behavior of the heat flow on the walls is quite similar to that of the shear stress in the Couette flow problem, whereas a distinct wavy behavior is observed in an early time stage.

  14. Effect of internal pressure and gas/liquid interface area on the CO mass transfer coefficient using hollow fibre membranes as a high mass transfer gas diffusing system for microbial syngas fermentation.

    Science.gov (United States)

    Yasin, Muhammad; Park, Shinyoung; Jeong, Yeseul; Lee, Eun Yeol; Lee, Jinwon; Chang, In Seop

    2014-10-01

    This study proposed a submerged hollow fibre membrane bioreactor (HFMBR) system capable of achieving high carbon monoxide (CO) mass transfer for applications in microbial synthesis gas conversion systems. Hydrophobic polyvinylidene fluoride (PVDF) membrane fibres were used to fabricate a membrane module, which was used for pressurising CO in water phase. Pressure through the hollow fibre lumen (P) and membrane surface area per unit working volume of the liquid (A(S)/V(L)) were used as controllable parameters to determine gas-liquid volumetric mass transfer coefficient (k(L)a) values. We found a k(L)a of 135.72 h(-1) when P was 93.76 kPa and AS/VL was fixed at 27.5m(-1). A higher k(L)a of 155.16 h(-1) was achieved by increasing AS/VL to 62.5m(-1) at a lower P of 37.23 kPa. Practicality of HFMBR to support microbial growth and organic product formation was assessed by CO/CO2 fermentation using Eubacterium limosum KIST612.

  15. Mass transfer across combustion gas thermal boundary layers - Power production and materials processing implications

    Science.gov (United States)

    Rosner, D. E.

    1985-01-01

    The effects of Soret diffusion (for vapors) and thermophoresis (for particles) are illustrated using recent optical experiments and boundary layer computations. Mass transfer rate augmentations of up to a factor of 1000 were observed and predicted for submicron-particle capture by cooled solid surfaces, while mass transfer suppressions of more than 10 to the -10th-fold were predicted for 'overheated' surfaces. It is noted that the results obtained are of interest in connection with such technological applications as fly-ash capture in power generation equipment and glass droplet deposition in optical-waveguide manufacture.

  16. Two-flux method for radiation heat transfer in anisotropic gas-particles media

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    [1]Schuster, A., Radiation through a foggy atmosphere, Astrophysics J., 1905, 21(1): 1-22.[2]Schwarzchild, K., Equilibrium of the Sun's atmosphere, Nachr. Ges. Wiss. Gottingen Math.-Phys. Klasse, 1906, (1): 41-53.[3]Maheu, B., Letoulouzan, J. N., Gouesbet, G., Four-flux models to solve the scattering transfer equation in terms of Loren-Mie parameters, Applied Optics, 1984, 23(19): 3353-3362.[4]Maheu, B., Gouesbet, G., Four-flux models to solve the scattering transfer equation: special cases, Applied Optics, 1986, 25(7): 1122-1128.[5]Roze, C., Girasole, T., Tafforin, A. G., Multiplayer four-flux model of scattering, emitting and absorbing media, Atmospheric Environment, 2001, 35: 5125-5130.[6]Modest, M. F., Radiative Heat Transfer, New York: McGraw-Hill Series in Mechanical Engineering, 1993.[7]Goodwin, D. G., Mitchner, M., Flyash radiative properties and effects on radiative heat transfer in coal-fired systems, International Journal of Heat and Mass Transfer, 1989, 32(4): 627-638.[8]Siegel, R., Howell, J. R., Thermal Radiation Heat Transfer, 2nd ed., New York: Hemisphere Publishing Corporation, 1980.[9]Irvine, T. F., Hartnett, J. P., Advances in Heat Transfer, Vol. 3, New York: Academic Press, 1966.[10]Rozé, C., Girasole, T., Grehan, G. et al., Average crossing parameter and forward scattering ratio values in four-flux model for multiple scattering media, Optics Communication, 2001, 194: 251-263.[11]Wall, T. F., Lowe, A., Wibberley, L. J. et al., Fly ash characteristics and radiative heat transfer in pulverized-coal-fired furnace, Combustion Science and Technology, 1981, 26: 107-121.[12]Ozisik, M. N., Radiative Transfer and Interactions with Conduction and Convection, New York: Wiley, 1973.[13]Gupta, R. P., Wall, T. F., Truelove, J. S., Radiative scatter by fly ash in pulverized-coal-fired furnace: application of the Monte Carlo method to anisotropic scatter, International Journal of Heat and Mass Transfer, 1983

  17. Velocity Slip and Interfacial Momentum Transfer in the Transient Section of Supersonic Gas-Droplet Two-Phase Flows

    Institute of Scientific and Technical Information of China (English)

    魏文韫; 朱家骅; 夏素兰; 戴光清; 高旭东

    2002-01-01

    Modelling and simulations are conducted on velocity slip and interfacial momentum transfer for super-sonic two-phase (gas-droplet) flow in the transient section inside and outside a Laval jet(L J). The initial velocity slipbetween gas and droplets causes an interfacial momentum transfer flux as high as (2.0-5.0) × 104 Pa. The relaxationtime corresponding to this transient process is in the range of 0.015-0.090 ms for the two-phase flow formed insidethe LJ and less than 0.5 ms outside the LJ. It demonstrates the unique performance of this system for application tofast chemical reactions using electrically active media with a lifetime in the order of 1 ms. Through the simulationsof the transient processes with initial Mach number Mg from 2.783 to 4.194 at different axial positions inside theLJ. it is found that Mg has the strongest effect on the process. The momentum flux increases as the Mach numberdecreases. Due to compression by the shock wave at the end of the L J, the flow pattern becomes two dimensionaland viscous outside the LJ. Laser Doppler velocimeter (LDV) measurements of droplet velocities outside the LJ arein reasonably good agreement with the results of the simulation.

  18. Gas transfer rates from airlifts used for concurrent aeration, carbon dioxide stripping, and recirculation

    Science.gov (United States)

    Airlifts simplify recirculating aquaculture systems and can potentially reduce capital costs and minimize maintenance issues. Airlifts have the ability to move and aerate water as well as degass the water of any carbon dioxide. This study evaluated the oxygen transfer and carbon dioxide removal abil...

  19. Mass Transfer Study of Chlorine Dioxide Gas Through Polymeric Packaging Materials

    Science.gov (United States)

    A continuous system for measuring the mass transfer of gaseous chlorine dioxide (ClO2), a strong oxidizing agent and used in food and pharmaceutical packaging, through 10 different types of polymeric packaging material was developed utilizing electrochemical sensor as a detector. Permeability, diff...

  20. Diagnostic System of Wireless Acoustic Emission Signal Transfer for Monitoring Oil-and-Gas Facilities

    Directory of Open Access Journals (Sweden)

    Skalsky, V.R.

    2016-01-01

    Full Text Available The structure of diagnostic 8-channel system for wireless transfer of acoustic emission information during monitoring the objects of long operation is revealed. The results of the development of algorithmic software for hardware system and personal computer, which performs system control and post-processing of acoustic emission information. are presented. The basic specifications of the system are described.

  1. Wind and Wave Characteristics Observed During the LUMINY Gas Transfer Experiments

    NARCIS (Netherlands)

    Caulliez, G.; Jaouen, L.; Larsen, S.E.; Hansen, F.Aa.; Lund, S.; Leeuw, G. de; Woolf, D.K.; Bowyer, P.A.; Leifer, I.; Kunz, G.J.; Nightingale, P.D.; Rhee, T.S.; Liddicoat, M.I.; Baker, J.; Rapsomanikis, S.; Hassoun, S.; Cohen, L.H.

    1999-01-01

    The parameterization of the greenhouse gas fluxes between the atmosphere and oceans as function of wind and sea state parameters remains a challenging problem, of key importance for climate modelling. It is well-known that exchange across the air-water interface of gases of poor solubility as carbon

  2. Experimental and numerical investigations of high temperature gas heat transfer and flow in a VHTR reactor core

    Science.gov (United States)

    Valentin Rodriguez, Francisco Ivan

    High pressure/high temperature forced and natural convection experiments have been conducted in support of the development of a Very High Temperature Reactor (VHTR) with a prismatic core. VHTRs are designed with the capability to withstand accidents by preventing nuclear fuel meltdown, using passive safety mechanisms; a product of advanced reactor designs including the implementation of inert gases like helium as coolants. The present experiments utilize a high temperature/high pressure gas flow test facility constructed for forced and natural circulation experiments. This work examines fundamental aspects of high temperature gas heat transfer applied to VHTR operational and accident scenarios. Two different types of experiments, forced convection and natural circulation, were conducted under high pressure and high temperature conditions using three different gases: air, nitrogen and helium. The experimental data were analyzed to obtain heat transfer coefficient data in the form of Nusselt numbers as a function of Reynolds, Grashof and Prandtl numbers. This work also examines the flow laminarization phenomenon (turbulent flows displaying much lower heat transfer parameters than expected due to intense heating conditions) in detail for a full range of Reynolds numbers including: laminar, transition and turbulent flows under forced convection and its impact on heat transfer. This phenomenon could give rise to deterioration in convection heat transfer and occurrence of hot spots in the reactor core. Forced and mixed convection data analyzed indicated the occurrence of flow laminarization phenomenon due to the buoyancy and acceleration effects induced by strong heating. Turbulence parameters were also measured using a hot wire anemometer in forced convection experiments to confirm the existence of the flow laminarization phenomenon. In particular, these results demonstrated the influence of pressure on delayed transition between laminar and turbulent flow. The heat

  3. Numerical simulation of gas flow and heat transfer in a rough microchannel using the lattice Boltzmann method.

    Science.gov (United States)

    Dorari, Elaheh; Saffar-Avval, Majid; Mansoori, Zohreh

    2015-12-01

    In microfluidics, two important factors responsible for the differences between the characteristics of the flow and heat transfer in microchannels and conventional channels are rarefaction and surface roughness which are studied in the present work. An incompressible gas flow in a microchannel is simulated two dimensionally using the lattice Boltzmann method. The flow is in the slip regime and surface roughness is modeled by both regular and Gaussian random distribution of rectangular modules. The effects of relative surface roughness height and Knudsen number on gaseous flow and heat transfer are studied. It was shown that as the relative roughness height increases, the Poiseuille number increases and the Nusselt number has a decreasing or increasing trend, depending on the degree of rarefaction. A comparison between the flow and heat transfer characteristics in regular and random distribution of surface roughness demonstrates that in regular roughness, circular flows are more pronounced; Poiseuille number is higher and Nusselt number is lower than that of its equivalent random roughness.

  4. Extension of Weighted Sum of Gray Gas Data to Mathematical Simulation of Radiative Heat Transfer in a Boiler with Gas-Soot Media

    Directory of Open Access Journals (Sweden)

    Samira Gharehkhani

    2014-01-01

    Full Text Available In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site.

  5. Extension of weighted sum of gray gas data to mathematical simulation of radiative heat transfer in a boiler with gas-soot media.

    Science.gov (United States)

    Gharehkhani, Samira; Nouri-Borujerdi, Ali; Kazi, Salim Newaz; Yarmand, Hooman

    2014-01-01

    In this study an expression for soot absorption coefficient is introduced to extend the weighted-sum-of-gray gases data to the furnace medium containing gas-soot mixture in a utility boiler 150 MWe. Heat transfer and temperature distribution of walls and within the furnace space are predicted by zone method technique. Analyses have been done considering both cases of presence and absence of soot particles at 100% load. To validate the proposed soot absorption coefficient, the expression is coupled with the Taylor and Foster's data as well as Truelove's data for CO2-H2O mixture and the total emissivities are calculated and compared with the Truelove's parameters for 3-term and 4-term gray gases plus two soot absorption coefficients. In addition, some experiments were conducted at 100% and 75% loads to measure furnace exit gas temperature as well as the rate of steam production. The predicted results show good agreement with the measured data at the power plant site.

  6. Subparsec-scale dynamics of a dusty gas disk exposed to anisotropic AGN radiation with frequency-dependent radiative transfer

    CERN Document Server

    Namekata, Daisuke

    2016-01-01

    We explore the gas dynamics near the dust sublimation radius of active galactic nucleus (AGN). For the purpose, we perform axisymmetric radiation hydrodynamic simulations of a dusty gas disk of radius $\\approx 1\\,\\mathrm{pc}$ around a supermassive black hole of mass $10^{7}\\,\\mathrm{M_{\\odot}}$ taking into account (1) anisotropic radiation of accretion disk, (2) X-ray heating by corona, (3) radiative transfer of infrared (IR) photons reemitted by dust, (4) frequency dependency of direct and IR radiations, and (5) separate temperatures for gas and dust. As a result, we find that for Eddington ratio $\\approx 0.77$, a nearly neutral, dense ($\\approx 10^{6\\operatorname{-}8}\\;\\mathrm{cm^{-3}}$), geometrically-thin ($h/r<0.06$) disk forms with a high velocity ($\\approx 200 \\sim 3000\\;\\mathrm{km/s}$) dusty outflow launched from the disk surface. The disk temperature is determined by the balance between X-ray heating and various cooling, and the disk is almost supported by thermal pressure. Contrary to \\citet{krol...

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

    Indian Academy of Sciences (India)

    Nilanjan Coomar; Ravikiran Kadoli

    2010-02-01

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

  8. Analysis of Gas Radiative Transfer Using Box Model and Its Comparison with Gray Band Approximation

    Institute of Scientific and Technical Information of China (English)

    Yuying Liu; Xinxin Zhang

    2003-01-01

    On the basis of a wide range survey of various models or treatment methods for the calculation of radiative properties of gases, box model, which is similar to the gray band approximation of spectral band model, was applied to evaluate the gas properties in this paper. In order to compare the accuracy of box model with that of gray band approximation of spectral band models, a typical one-dimensional gas radiation problem was analyzed using discrete ordinate method. Comparing with the widely used gray band approximation of narrow band model or exponential wide band model, box model can well evaluate the radiation source term of the radiative problem.It also has the advantages of simplicity and easy to code, so it is practicable and useful for some complex engineering problems.

  9. Experimental Study on Gas-Solid Mass Transfer in Circulating Fluidized Beds%循环流化床气固传质实验研究

    Institute of Scientific and Technical Information of China (English)

    王琳娜; 张苓; 靳东杰; 李静海

    2002-01-01

    This study is devoted to gas-solid mass transfer behavior in heterogeneous two-phase flow. Experiments were carried out in a cold circulating fluidized bed of 3.0 m in height and 72 mm in diameter with naphthalene particles. Axial and radial distributions of sublimated naphthalene concentration in air were measured with an online concentration monitoring system HP GC-MS. Mass transfer coefficients were obtained under various operating conditions, showing that heterogeneous flow structure strongly influences the axial and radial profiles of mass transfer coefficients. In the bottom dense region, mass transfer rate is high due to intensive dynamic behavior and higher relative slip velocity between gas and clusters. In the middle transition region and the upper dilute region, as a result of low mass transfer driving force and the influence of flow structure, mass transfer rate distribution becomes non-uniform. In conclusion, among the operating parameters influencing mass transfer coefficients, the superficial gas velocity is the most important factor and the solid circulation rate should be also taken into account.

  10. Heat Transfer Measurements and Predictions on a Power Generation Gas Turbine Blade

    Science.gov (United States)

    Giel, Paul W.; Bunker, Ronald S.; VanFossen, G. James; Boyle, Robert J.

    2000-01-01

    Detailed heat transfer measurements and predictions are given for a power generation turbine rotor with 129 deg of nominal turning and an axial chord of 137 mm. Data were obtained for a set of four exit Reynolds numbers comprised of the design point of 628,000, -20%, +20%, and +40%. Three ideal exit pressure ratios were examined including the design point of 1.378, -10%, and +10%. Inlet incidence angles of 0 deg and +/-2 deg were also examined. Measurements were made in a linear cascade with highly three-dimensional blade passage flows that resulted from the high flow turning and thick inlet boundary layers. Inlet turbulence was generated with a blown square bar grid. The purpose of the work is the extension of three-dimensional predictive modeling capability for airfoil external heat transfer to engine specific conditions including blade shape, Reynolds numbers, and Mach numbers. Data were obtained by a steady-state technique using a thin-foil heater wrapped around a low thermal conductivity blade. Surface temperatures were measured using calibrated liquid crystals. The results show the effects of strong secondary vortical flows, laminar-to-turbulent transition, and also show good detail in the stagnation region.

  11. The relationship between ocean surface turbulence and air-sea gas transfer velocity: An in-situ evaluation

    Science.gov (United States)

    Esters, L.; Landwehr, S.; Sutherland, G.; Bell, T. G.; Saltzman, E. S.; Christensen, K. H.; Miller, S. D.; Ward, B.

    2016-05-01

    Although the air-sea gas transfer velocity k is usually parameterized with wind speed, the so-called small-eddy model suggests a relationship between k and ocean surface dissipation of turbulent kinetic energy ɛ. Laboratory and field measurements of k and ɛ have shown that this model holds in various ecosystems. Here, field observations are presented supporting the theoretical model in the open ocean. These observations are based on measurements from the Air-Sea Interaction Profiler and eddy covariance CO2 and DMS air-sea flux data collected during the Knorr11 cruise. We show that the model results can be improved when applying a variable Schmidt number exponent compared to a commonly used constant value of 1/2. Scaling ɛ to the viscous sublayer allows us to investigate the model at different depths and to expand its applicability for more extensive data sets.

  12. Large volume injection in gas chromatography using the through oven transfer adsorption desorption interface operating under vacuum.

    Science.gov (United States)

    Aragón, Álvaro; Toledano, Rosa M; Gea, Sara; Cortés, José M; Vázquez, Ana M; Villén, Jesús

    2014-06-01

    The present work describes a modification of the Through Oven Transfer Adsorption Desorption (TOTAD) interface, consisting of coupling a vacuum system to reduce the consumption of the helium needed to totally remove the eluent for large volume injection (LVI) in gas chromatography (GC). Two different retention materials in the liner of the TOTAD interface were evaluated: Tenax TA, which was seen to be unsuitable for working under vacuum conditions, and polydimethylsiloxane (PDMS), which provided satisfactory repeatability as well as a good sensitivity. No variability was observed in the retention times in either case. Solutions containing organophosphorous pesticides in two different solvents, a polar (methanol/water) and a non-polar (hexane) solvent, were used to evaluate the modification. The vacuum system coupled to the TOTAD interface allowed up to 90% helium to be saved without affecting the performance.

  13. Gas-solid turbulent flow and heat transfer with collision effect in a vertical pipe

    Energy Technology Data Exchange (ETDEWEB)

    Saffar-Avval, M.; Basirat Tabrizi, H.; Ramezani, P. [Department of Mechanical Engineering, Amirkabir University of Technology, PO Box 15875-4413, Tehran (Iran); Mansoori, Z. [Energy Research Center, Amirkabir University of Technology, PO Box 15875-4413, Tehran (Iran)

    2007-01-15

    A turbulent gas-solid suspension upward flow in a vertical pipe is simulated numerically using Eulerian-Lagrangian approach. Particle-particle and particle-wall collisions are simulated based on deterministic approach. The influence of particle collisions on the particle concentration, mean temperature and fluctuating velocities are investigated. Numerical results are presented for different values of loading ratios. The profiles of particle concentration, mean velocity and temperature are shown to be flatter by considering inter-particle collisions, while this effect on the gas mean velocity and temperature is not significant. It is demonstrated that the effect of inter-particle collisions have a dramatic influence on the particle fluctuation velocity. It is shown that the profiles of particle concentration and particle velocity are flattened due to inter-particle collisions and this effect becomes more pronounced with increasing loading ratio. Also, the attenuation of turbulence by inter-particle collisions in the core region of the pipe is increased by increasing loading ratio. (author)

  14. Influence of Metal Transfer Stability and Shielding Gas Composition on CO and CO2 Emissions during Short-circuiting MIG/MAG Welding

    Directory of Open Access Journals (Sweden)

    Valter Alves de Meneses

    Full Text Available Abstract: Several studies have demonstrated the influence of parameters and shielding gas on metal transfer stability or on the generation of fumes in MIG/MAG welding, but little or nothing has been discussed regarding the emission of toxic and asphyxiating gases, particularly as it pertains to parameterization of the process. The purpose of this study was to analyze and evaluate the effect of manufacturing aspects of welding processes (short-circuit metal transfer stability and shielding gas composition on the gas emission levels during MIG/MAG welding (occupational health and environmental aspects. Using mixtures of Argon with CO2 and O2 and maintaining the same average current and the same weld bead volume, short-circuit welding was performed with carbon steel welding wire in open (welder’s breathing zone and confined environments. The welding voltage was adjusted to gradually vary the transfer stability. It was found that the richer the composition of the shielding gas is in CO2, the more CO and CO2 are generated by the arc. However, unlike fume emission, voltage and transfer stability had no effect on the generation of these gases. It was also found that despite the large quantity of CO and CO2 emitted by the arc, especially when using pure CO2 shielding gas, there was no high level residual concentration of CO and CO2 in or near the worker’s breathing zone, even in confined work cells.

  15. Efficient transfer of positrons from a buffer-gas-cooled accumulator into an orthogonally oriented superconducting solenoid for antihydrogen studies

    CERN Document Server

    Comeau, D; Fitzakerley, D; George, M C; Hessels, E A; Storry, C H; Weel, M; Grzonka, D; Oelert, W; Gabrielse, G; Kalra, R; Kolthammer, W S; McConnell, R; Richerme, P; Mullers, A; Walz, J

    2012-01-01

    Positrons accumulated in a room-temperature buffer-gas-cooled positron accumulator are efficiently transferred into a superconducting solenoid which houses the ATRAP cryogenic Penning trap used in antihydrogen research. The positrons are guided along a 9 m long magnetic guide that connects the central field lines of the 0.15 T field in the positron accumulator to the central magnetic field lines of the superconducting solenoid. Seventy independently controllable electromagnets are required to overcome the fringing field of the large-bore superconducting solenoid. The guide includes both a 15 degrees upward bend and a 105 degrees downward bend to account for the orthogonal orientation of the positron accumulator with respect to the cryogenic Penning trap. Low-energy positrons ejected from the accumulator follow the magnetic field lines within the guide and are transferred into the superconducting solenoid with nearly 100% efficiency. A 7 m long 5 cm diameter stainless-steel tube and a 20 mm long, 1.5 mm diamet...

  16. The influence of adsorption coating on molecular heat transfer in the system `rarefied gas — metal'

    Science.gov (United States)

    Ukhov, A. I.; Borisov, S. F.; Porodnov, B. T.

    2010-03-01

    Based on the classical concept of atomic motion and the Goodman and Wachman lattice theory, we have developed a computer program to model the equilibrium and non-equilibrium scattering of helium atoms by 3D tungsten crystal lattice with allowance for adsorption surface coating. Within the concept of energy accommodation coefficient, we have calculated the rate of molecular heat transfer of helium to clean tungsten surface or to tungsten surface partially covered with an adsorbate. The calculations were performed for various surface temperatures. The calculated dependences were compared to test data obtained in experiments with surfaces controlled in terms of their chemical composition. Within the developed approach, the simulations proved capable of providing an adequate description to experimental data obtained for the equilibrium energy accommodation coefficient on the clean surface, and also for the non-equilibrium energy accommodation coefficient for the surface partially covered with adsorbate.

  17. Characterization of Gas-Phase Organics Using Proton Transfer Reaction Time-of-Flight Mass Spectrometry: Aircraft Turbine Engines.

    Science.gov (United States)

    Kilic, Dogushan; Brem, Benjamin T; Klein, Felix; El-Haddad, Imad; Durdina, Lukas; Rindlisbacher, Theo; Setyan, Ari; Huang, Rujin; Wang, Jing; Slowik, Jay G; Baltensperger, Urs; Prevot, Andre S H

    2017-03-17

    Nonmethane organic gas emissions (NMOGs) from in-service aircraft turbine engines were investigated using a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) at an engine test facility at Zurich Airport, Switzerland. Experiments consisted of 60 exhaust samples for seven engine types (used in commercial aviation) from two manufacturers at thrust levels ranging from idle to takeoff. Emission indices (EIs) for more than 200 NMOGs were quantified, and the functional group fractions (including acids, carbonyls, aromatics, and aliphatics) were calculated to characterize the exhaust chemical composition at different engine operation modes. Total NMOG emissions were highest at idling with an average EI of 7.8 g/kg fuel and were a factor of ∼40 lower at takeoff thrust. The relative contribution of pure hydrocarbons (particularly aromatics and aliphatics) of the engine exhaust decreased with increasing thrust while the fraction of oxidized compounds, for example, acids and carbonyls increased. Exhaust chemical composition at idle was also affected by engine technology. Older engines emitted a higher fraction of nonoxidized NMOGs compared to newer ones. Idling conditions dominated ground level organic gas emissions. Based on the EI determined here, we estimate that reducing idle emissions could substantially improve air quality near airports.

  18. Direct measurements of wind-water momentum coupling in a marsh with emergent vegetation and implications for gas transfer estimates

    Science.gov (United States)

    Tse, I.; Poindexter, C.; Variano, E. A.

    2013-12-01

    Among the numerous ecological benefits of restoring wetlands is carbon sequestration. As emergent vegetation thrive, atmospheric CO2 is removed and converted into biomass that gradually become additional soil. Forecasts and management for these systems rely on accurate knowledge of gas exchange between the atmosphere and the wetland surface waters. Our previous work showed that the rate of gas transfer across the air-water interface is affected by the amount of water column mixing caused by winds penetrating through the plant canopy. Here, we present the first direct measurements of wind-water momentum coupling made within a tule marsh. This work in Twitchell Island in the California Delta shows how momentum is imparted into the water from wind stress and that this wind stress interacts with the surface waters in an interesting way. By correlating three-component velocity signals from a sonic anemometer placed within the plant canopy with data from a novel Volumetric Particle Imager (VoPI) placed in the water, we measure the flux of kinetic energy through the plant canopy and the time-scale of the response. We also use this unique dataset to estimate the air-water drag coefficient using an adjoint method.

  19. Heat transfer in a compact tubular heat exchanger with helium gas at 3.5 MPa

    Science.gov (United States)

    Olson, Douglas A.; Glover, Michael P.

    1990-01-01

    A compact heat exchanger was constructed consisting of circular tubes in parallel brazed to a grooved base plate. This tube specimen heat exchanger was tested in an apparatus which radiatively heated the specimen on one side at a heat flux of up to 54 W/sq cm, and cooled the specimen with helium gas at 3.5 MPa and Reynolds numbers of 3000 to 35,000. The measured friction factor of the tube specimen was lower than that of a circular tube with fully developed turbulent flow, although the uncertainty was high due to entrance and exit losses. The measured Nusselt number, when modified to account for differences in fluid properties between the wall and the cooling fluid, agreed with past correlations for fully developed turbulent flow in circular tubes.

  20. Spatiotemporal patterns in methane flux and gas transfer velocity at low wind speeds: Implications for upscaling studies on small lakes

    Science.gov (United States)

    Schilder, J.; Bastviken, D.; Hardenbroek, M.; Heiri, O.

    2016-06-01

    Lakes contribute significantly to the global natural emissions of methane (CH4) and carbon dioxide. However, to accurately incorporate them into the continental carbon balance more detailed surveys of lacustrine greenhouse gas emissions are needed, especially in respect to spatiotemporal variability and to how this affects the upscaling of results. We investigated CH4 flux from a small, wind-shielded lake during 10 field trips over a 14 month period. We show that floating chambers may be used to calibrate the relationship between gas transfer velocity (k) and wind speed at 10 m height (U10) to the local system, in order to obtain more accurate estimates of diffusive CH4 flux than by applying general models predicting k based on U10. We confirm earlier studies indicating strong within-lake spatial variation in this relationship and in ebullitive CH4 flux within the lake basin. However, in contrast to the pattern reported in other studies, ebullitive CH4 flux was highest in the central parts of the lake. Our results indicate positive relationships between k and U10 at very low U10 (0-3 m s-1), which disagrees with earlier suggestions that this relationship may be negligible at low U10 values. We estimate annually averaged open water CH4 emission from Lake Gerzensee to be 3.6-5.8 mmol m-2 d-1. Our data suggest that estimates of greenhouse gas emissions from aquatic systems to the atmosphere based on the upscaling of short-term and small-scale measurements can be improved if both spatial and temporal variabilities of emissions are taken into account.

  1. Quantification of diesel exhaust gas phase organics by a thermal desorption proton transfer reaction mass spectrometer

    Directory of Open Access Journals (Sweden)

    M. H. Erickson

    2012-02-01

    Full Text Available A new approach was developed to measure the total abundance of long chain alkanes (C12 and above in urban air using thermal desorption with a proton transfer reaction mass spectrometer (PTR-MS. These species are emitted in diesel exhaust and may be important precursors to secondary organic aerosol production in urban areas. Long chain alkanes undergo dissociative proton transfer reactions forming a series of fragment ions with formula CnH2n+1. The yield of the fragment ions is a function of drift conditions. At a drift field strength of 80 Townsends, the most abundant ion fragments from C10 to C16 n-alkanes were m/z 57, 71 and 85. The PTR-MS is insensitive to n-alkanes less than C8 but displays an increasing sensitivity for larger alkanes. Higher drift field strengths yield greater normalized sensitivity implying that the proton affinity of the long chain n-alkanes is less than H2O. Analysis of diesel fuel shows the mass spectrum was dominated by alkanes (CnH2n+1, monocyclic aromatics, and an ion group with formula CnH2n−1 (m/z 97, 111, 125, 139. The PTR-MS was deployed in Sacramento, CA during the Carbonaceous Aerosols and Radiative Effects Study field experiment in June 2010. The ratio of the m/z 97 to 85 ion intensities in ambient air matched that found in diesel fuel. Total diesel exhaust alkane concentrations calculated from the measured abundance of m/z 85 ranged from the method detection limit of ~1 μg m−3 to 100 μg m−3 in several air pollution episodes. The total diesel exhaust alkane concentration determined by this method was on average a factor of 10 greater than the sum of alkylbenzenes associated with spark ignition vehicle exhaust.

  2. Heat transfer in a compact heat exchanger containing rectangular channels and using helium gas

    Science.gov (United States)

    Olson, D. A.

    1991-01-01

    Development of a National Aerospace Plane (NASP), which will fly at hypersonic speeds, require novel cooling techniques to manage the anticipated high heat fluxes on various components. A compact heat exchanger was constructed consisting of 12 parallel, rectangular channels in a flat piece of commercially pure nickel. The channel specimen was radiatively heated on the top side at heat fluxes of up to 77 W/sq cm, insulated on the back side, and cooled with helium gas flowing in the channels at 3.5 to 7.0 MPa and Reynolds numbers of 1400 to 28,000. The measured friction factor was lower than that of the accepted correlation for fully developed turbulent flow, although the uncertainty was high due to uncertainty in the channel height and a high ratio of dynamic pressure to pressure drop. The measured Nusselt number, when modified to account for differences in fluid properties between the wall and the cooling fluid, agreed with past correlations for fully developed turbulent flow in channels. Flow nonuniformity from channel-to-channel was as high as 12 pct above and 19 pct below the mean flow.

  3. Characterisation of the volatile profiles of infant formulas by proton transfer reaction-mass spectrometry and gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    Ruth, van S.M.; Floris, V.; Fayoux, S.

    2006-01-01

    The volatile profiles of 13 infant formulas were evaluated by proton transfer reaction-mass spectrometry (PTR-MS) and gas chromatography¿mass spectrometry (GC¿MS). The infant formulas varied in brand (Aptamil, Cow & Gate, SMA), type (for different infant target groups) and physical form (powder/

  4. Modelling of heat and mass transfer in a granular medium during high-temperature air drying. Effect of the internal gas pressure

    Science.gov (United States)

    Othmani, Hammouda; Hassini, Lamine; Lamloumi, Raja; El Cafsi, Mohamed Afif

    2016-02-01

    A comprehensive internal heat and water transfer model including the gas pressure effect has been proposed in order to improve the industrial high-temperature air drying of inserts made of agglomerated sand. In this model, the internal gas phase pressure effect was made perfectly explicit, by considering the liquid and vapour transfer by filtration and the liquid expulsion at the surface. Wet sand enclosed in a tight cylindrical glass bottle dried convectively at a high temperature was chosen as an application case. The model was validated on the basis of the experimental average water content and core temperature curves for drying trials at different operating conditions. The simulations of the spatio-temporal distribution of internal gas pressure were performed and interpreted in terms of product potential damage. Based on a compromise between the drying time and the pressure increase, a simple drying cycle was implemented in order to optimize the drying process.

  5. Transfer-matrix study of a hard-square lattice gas with two kinds of particles and density anomaly.

    Science.gov (United States)

    Oliveira, Tiago J; Stilck, Jürgen F

    2015-09-01

    Using transfer matrix and finite-size scaling methods, we study the thermodynamic behavior of a lattice gas with two kinds of particles on the square lattice. Only excluded volume interactions are considered, so that the model is athermal. Large particles exclude the site they occupy and its four first neighbors, while small particles exclude only their site. Two thermodynamic phases are found: a disordered phase where large particles occupy both sublattices with the same probability and an ordered phase where one of the two sublattices is preferentially occupied by them. The transition between these phases is continuous at small concentrations of the small particles and discontinuous at larger concentrations, both transitions are separated by a tricritical point. Estimates of the central charge suggest that the critical line is in the Ising universality class, while the tricritical point has tricritical Ising (Blume-Emery-Griffiths) exponents. The isobaric curves of the total density as functions of the fugacity of small or large particles display a minimum in the disordered phase.

  6. Regularities pertinent to heat transfer between torch gas layers and steam boiler firebox waterwalls. Part I. Geometrical and physical torch model as a source of heat radiation

    Science.gov (United States)

    Makarov, A. N.

    2014-09-01

    The progress seen in the 19th-21st centuries in the development of methods for calculating heat transfer in torch furnaces, fireboxes, and combustion chambers is analyzed. Throughout the 20th century, calculations of heat transfer were carried out based on the law for radiation from solid bodies deduced by Y. Stefan and L. Boltzmann. It is shown that the use of this law for calculating heat transfer of a torch (a gaseous source of radiation) in heating furnaces and power-generating installations leads to incorrect results. It is substantiated that there is crisis of methods for calculating heat transfer in torch furnaces and power-generating installations. Geometrical and physical torch models in the form of radiating cylindrical gas volumes as sources of heat radiation are proposed for overcoming this crisis.

  7. Local Liquid Side Mass Transfer Model in Gas-Liquid-Solid Three-Phase Flow Airlift Loop Reactor for Newtonian and Non-Newtonian Fluids

    Institute of Scientific and Technical Information of China (English)

    闻建平; 贾晓强; 毛国柱

    2004-01-01

    A small scale isotropic mass transfer model was developed for the local liquid side mass transfer coefficients in gas-liquid-solid three-phase flow airlift loop reactor for Newtonian and non-Newtonian fluids. It is based on Higbie's penetration theory and Kolmogoroff's theory of isotropic turbulence with kl=3√2D∈11/3/π(η1-1/3-λf-1/3)where e1 is local rate of energy dissipation, Af is the local microscale, r/l is the local Kolmogoroff scale and D is the diffusion coefficient. The capability of the proposed model is discussed in the light of experimental data obtained from 12 L gas-liquid-solid three-phase flow airlift loop reactor using Newtonian and non-Newtonian fluids. Good agreement with the experimental data was obtained over a wide range of conditions suggesting a general applicability of the proposed model.

  8. Monitoring gas retention and slurry transport during the transfer of waste from Tank 241-C-106 to Tank 241-AY-102

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, C.W.; Erian, F.F.; Meyer, P.A. [and others

    1997-07-01

    The retained gas volume can be estimated by several methods. All of these methods have significant uncertainties, but together they form a preponderance of evidence that describes the gas retention behavior of the tank. The methods are (1) an increase in nonconvective layer thickness; (2) a waste surface level rise (surface level effect [SLE] model); (3) the barometric pressure effect (BPE model); (4) direct void measurement; and (5) the consequences of the transfer process. The nonconvective layer thickness can be determined with sufficient accuracy to describe the overall waste configuration by means of temperature profiles or densitometer indications. However, the presence of a nonconvective layer does not necessarily indicate significant gas retention, and small changes in layer thickness that could quantify gas retention cannot be detected reliably with the methods available. The primary value of this measurement is in establishing the actual {open_quotes}fluffing factor{close_quotes} for thermal calculations. Surface level rise is not a useful measure of gas retention in Tank 241-C-106 (C-106) since the waste level fluctuates with regular makeup water additions. In Tank 241-AY-102 (AY-102) with the existing ventilation system it should be possible to determine the gas retention rate within 30-60% uncertainty from the surface level rise, should a significant rise be observed. The planned ventilation system upgrades in AY- 102 will greatly reduce the exhaust flow and the headspace humidity, and the evaporation rate should be significantly lower when transfers begin. This could reduce the uncertainty in gas retention rate estimates to around {+-} 10%.

  9. Conclusions of the commission: property transfer of natural gas transport networks; Conclusions de la commission: transfert de propriete des reseaux de transport de gaz naturel

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-05-01

    This document deals with the evolution of the avoidance of the natural gas transport allowances and their transfers modalities. The first part recalls the juridical, technical and economical situation and the european context taking into account by the commission in this project. The commission choices of the evaluation methods are then presented. The evaluations and the conclusions of the commission are presented in the last part. (A.L.B.)

  10. Flow pattern-based mass and heat transfer and frictional drag of gas-non-Newtonian liquid flow in helical coil: two- and three-phase systems

    Science.gov (United States)

    Thandlam, Anil Kumar; Das, Chiranjib; Majumder, Subrata Kumar

    2016-08-01

    Investigation of wall-liquid mass transfer and heat transfer phenomena with gas-Newtonian and non-Newtonian fluids in vertically helical coil reactor have been reported in this article. Experiments were conducted to investigate the effect of various dynamic and geometric parameters on mass and heat transfer coefficients in the helical coil reactor. The flow pattern-based heat and mass transfer phenomena in the helical coil reactor are highlighted at different operating conditions. The study covered a wide range of geometric parameters such as diameter of the tube (d t ), diameter of the coil (D c ), diameter of the particle (d p ), pitch difference (p/D c ) and concentrations of non-Newtonian liquid. The correlation models for the heat and mass transfer coefficient based on the flow pattern are developed which may be useful in process scale-up of the helical coil reactor for industrial application. The frictional drag coefficient was also estimated and analyzed by mass transfer phenomena based on the electrochemical method.

  11. Influence of fluid-mechanical characteristics of the system on the volumetric mass transfer coefficient and gas dispersion in three-phase system

    Directory of Open Access Journals (Sweden)

    Knežević Milena M.

    2014-01-01

    Full Text Available Distribution of gas bubbles and volumetric mass transfer coefficient, Kla, in a three phase system, with different types of solid particles at different operation conditions were studied in this paper. The ranges of superficial gas and liquid velocities used in this study were 0,03-0,09 m/s and 0-0,1 m/s, respectively. The three different types of solid particles were used as a bed in the column (glass dp=3 mm, dp=6 mm; ceramic dp=6 mm. The experiments were carried out in a 2D plexiglas column, 278 x 20,4 x 500 mm and in a cylindrical plexiglas column, with a diameter of 64 mm and a hight of 2000 mm. The Kla coefficient increased with gas and liquid velocities. Results showed that the volumetric mass transfer coefficient has a higher values in three phase system, with solid particles, compared with two phase system. The particles properties (diameter and density have a major impact on oxygen mass transfer in three phase systems.

  12. Experimental investigation of the liquid volumetric mass transfer coefficient for upward gas-liquid two-phase flow in rectangular microchannels

    Directory of Open Access Journals (Sweden)

    X. Y. Ji

    2010-12-01

    Full Text Available The gas-liquid two-phase mass transfer process in microchannels is complicated due to the special dynamical characteristics. In this work, a novel method was explored to measure the liquid side volumetric mass transfer coefficient kLa. Pressure transducers were utilized to measure the pressure variation of upward gas-liquid two-phase flow in three vertical rectangular microchannels and the liquid side volumetric mass transfer coefficient kLa was calculated through the Pressure-Volume-Temperature correlation of the gas phase. Carbon dioxide-water, carbon dioxide-ethanol and carbon dioxide-n-propanol were used as working fluids, respectively. The dimensions of the microchannels were 40 µm×240 µm (depth×width, 100 µm×800 µm and 100 µm×2000 µm, respectively. Results showed that the channel diameter and the capillary number influence kLa remarkably and that the maximum value of kLa occurs in the annular flow regime. A new correlation of kLa was proposed based on the Sherwood number, Schmidt number and the capillary number. The predicted values of kLa agreed well with the experimental data.

  13. H. R. 5740: Barrow Gas Field Transfer Act of 1984. A bill introduced by the Committee on Interior and Insular Affairs, US House of Representatives, Ninety-Eighth Congress, Second Session, May 24 and June 14, 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    The amended text of H.R. 5740 as it was submitted to the House for consideration delineates the transfer of natural gas rights to the North Slope Borough contained in the Barrow gas fields and the Walakpa discovery site. The conveyance includes support facilities and other interests for the purpose of exploring for and producing natural gas. The Bill specifies privileges and limitations under the Alaska Native Claims Settlement Act. Entitled the ''Barrow Gas Field Transfer Act of 1984'', the Bill was submitted to the second session of the 98th Congress.

  14. Development of transfer zones and location of oil and gas fields in frontal part of Bolivian Andean fold-and-thrust belt

    Energy Technology Data Exchange (ETDEWEB)

    Baby, P. (Orstom, Santa Cruz (Bolivia)); Specht, M.; Colletta, B.; Letouzey, J. (Institut Francais du Petrole, Rueil-Malmaison (France)); Mendez, E. (YPFB, Santa Cruz (Bolivia)); Guillier, B. (IFEA, Santa Cruz (Bolivia))

    1993-02-01

    The frontal part of the Bolivian Andean thrust belt consists of a thick series of paleozoic to cenozoic sedimentary rocks (5 to 8 km thick) which are folded and thrusted towards the east on a sole thrust at the base of paleozoic series. The front of this tectonic wedge is characterized by transfer zones of various scales and geometries. The main oil and gas fields are located in these transfer zones. A study realized from YPFB (Yacimientos Petroliferos Fiscales Bolivianos) seismic data shows that in all the cases, the deformation is controlled by the geometry and thickness variations of the paleozoic basin. The most spectacular transfer zone appears at the bolivian orocline scale and corresponds to the famous bending of the andean thrust front close to Santa Cruz. More to the south (19 to 22[degrees] S) the southern foreland fold and thrust belt is characterized by a set of local right lateral offset transfer zones ([open quotes]en echellon[close quotes] folds). The difference of geometry and scale of the transfer zones seems to be related to the variation of the angle value between the shortening direction and the direction of the paleozoic basin borders. In order to test our interpretation, to constrain the boundary conditions and to study the thrust propagation sequence, we performed a set of analog model experiments whose 3D visualization was analyzed by computerized X-ray tomography.

  15. Analysis of Heat Transfer and Pressure Drop for a Gas Flowing Through a set of Multiple Parallel Flat Plates at High Temperatures

    Science.gov (United States)

    Einstein, Thomas H.

    1961-01-01

    Equations were derived representing heat transfer and pressure drop for a gas flowing in the passages of a heater composed of a series of parallel flat plates. The plates generated heat which was transferred to the flowing gas by convection. The relatively high temperature level of this system necessitated the consideration of heat transfer between the plates by radiation. The equations were solved on an IBM 704 computer, and results were obtained for hydrogen as the working fluid for a series of cases with a gas inlet temperature of 200 R, an exit temperature of 5000 0 R, and exit Mach numbers ranging from 0.2 to O.8. The length of the heater composed of the plates ranged from 2 to 4 feet, and the spacing between the plates was varied from 0.003 to 0.01 foot. Most of the results were for a five- plate heater, but results are also given for nine plates to show the effect of increasing the number of plates. The heat generation was assumed to be identical for each plate but was varied along the length of the plates. The axial variation of power used to obtain the results presented is the so-called "2/3-cosine variation." The boundaries surrounding the set of plates, and parallel to it, were assumed adiabatic, so that all the power generated in the plates went into heating the gas. The results are presented in plots of maximum plate and maximum adiabatic wall temperatures as functions of parameters proportional to f(L/D), for the case of both laminar and turbulent flow. Here f is the Fanning friction factor and (L/D) is the length to equivalent diameter ratio of the passages in the heater. The pressure drop through the heater is presented as a function of these same parameters, the exit Mach number, and the pressure at the exit of the heater.

  16. Enhancement of Oxygen Mass Transfer and Gas Holdup Using Palm Oil in Stirred Tank Bioreactors with Xanthan Solutions as Simulated Viscous Fermentation Broths

    Directory of Open Access Journals (Sweden)

    Suhaila Mohd Sauid

    2013-01-01

    Full Text Available Volumetric mass transfer coefficient (kLa is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h−1. It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.

  17. Modeling mass transfer in solid oxide fuel cell anode: II. H2/CO co-oxidation and surface diffusion in synthesis-gas operation

    Science.gov (United States)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2016-08-01

    Following the previous work on comparing performance of Fickian, Stefan-Maxwell and dusty-gas model for mass transfer in single fuel system, this article is focused on the electrochemistry and transport in the anode of solid oxide fuel cell using H2sbnd H2Osbnd COsbnd CO2sbnd N2 hybrid fuel. Under the standard framework of the dusty-gas model combined with the Butler-Volmer equation, it carries out a macroscopic area-specific modeling work. More specifically, two variables of hydrogen current fraction and enhancement factor are well defined and solved for the electrochemical co-oxidation of H2 and CO, and the diffusion equivalent circuit model is introduced to describe more comprehensively the resistance of mass transfer including molecular/Knudsen diffusion and surface diffusion. The model has been validated well in full region of Vsbnd I performance of an experimental anode-supported button cell. An approximate analytical solution of the hydrogen current fraction is also presented for explicit computation. Comparison between the results by different approaches for the effective diffusivity shows the importance of right mass-transfer modeling.

  18. Investigation of the effects of pressure gradient, temperature and wall temperature ratio on the stagnation point heat transfer for circular cylinders and gas turbine vanes

    Science.gov (United States)

    Nagamatsu, H. T.; Duffy, R. E.

    1984-01-01

    Low and high pressure shock tubes were designed and constructed for the purpose of obtaining heat transfer data over a temperature range of 390 to 2500 K, pressures of 0.3 to 42 atm, and Mach numbers of 0.15 to 1.5 with and without pressure gradient. A square test section with adjustable top and bottom walls was constructed to produce the favorable and adverse pressure gradient over the flat plate with heat gages. A water cooled gas turbine nozzle cascade which is attached to the high pressure shock tube was obtained to measuse the heat flux over pressure and suction surfaces. Thin-film platinum heat gages with a response time of a few microseconds were developed and used to measure the heat flux for laminar, transition, and turbulent boundary layers. The laminar boundary heat flux on the shock tube wall agreed with Mirel's flat plate theory. Stagnation point heat transfer for circular cylinders at low temperature compared with the theoretical prediction, but for a gas temperature of 922 K the heat fluxes were higher than the predicted values. Preliminary flat plate heat transfer data were measured for laminar, transition, and turbulent boundary layers with and without pressure gradients for free-stream temperatures of 350 to 2575 K and flow Mach numbers of 0.11 to 1.9. The experimental heat flux data were correlated with the laminar and turbulent theories and the agreement was good at low temperatures which was not the case for higher temperatures.

  19. Net sea–air CO2 flux uncertainties in the Bay of Biscay based on the choice of wind speed products and gas transfer parameterizations

    Directory of Open Access Journals (Sweden)

    P. Otero

    2013-05-01

    Full Text Available The estimation of sea–air CO2 fluxes is largely dependent on wind speed through the gas transfer velocity parameterization. In this paper, we quantify uncertainties in the estimation of the CO2 uptake in the Bay of Biscay resulting from the use of different sources of wind speed such as three different global reanalysis meteorological models (NCEP/NCAR 1, NCEP/DOE 2 and ERA-Interim, one high-resolution regional forecast model (HIRLAM-AEMet, winds derived under the Cross-Calibrated Multi-Platform (CCMP project, and QuikSCAT winds in combination with some of the most widely used gas transfer velocity parameterizations. Results show that net CO2 flux estimations during an entire seasonal cycle (September 2002–September 2003 may vary by a factor of ~ 3 depending on the selected wind speed product and the gas exchange parameterization, with the highest impact due to the last one. The comparison of satellite- and model-derived winds with observations at buoys advises against the systematic overestimation of NCEP-2 and the underestimation of NCEP-1. In the coastal region, the presence of land and the time resolution are the main constraints of QuikSCAT, which turns CCMP and ERA-Interim in the preferred options.

  20. Ultrasonic nebulization extraction-heating gas flow transfer-headspace single drop microextraction of essential oil from pericarp of Zanthoxylum bungeanum Maxim.

    Science.gov (United States)

    Wei, Shigang; Zhang, Huihui; Wang, Yeqiang; Wang, Lu; Li, Xueyuan; Wang, Yinghua; Zhang, Hanqi; Xu, Xu; Shi, Yuhua

    2011-07-22

    The ultrasonic nebulization extraction-heating gas flow transfer coupled with headspace single drop microextraction (UNE-HGFT-HS-SDME) was developed for the extraction of essential oil from Zanthoxylum bungeanum Maxim. The gas chromatography-mass spectrometry was applied to the determination of the constituents in the essential oil. The contents of the constituents from essential oil obtained by the proposed method were found to be more similar to those obtained by hydro-distillation (HD) than those obtained by ultrasonic nebulization extraction coupled with headspace single drop microextraction (UNE-HS-SDME). The heating gas flow was firstly used in the analysis of the essential oil to transfer the analytes from the headspace to the solvent microdrop. The relative standard deviations for determining the five major constituents were in the range from 1.5 to 6.7%. The proposed method is a fast, sensitive, low cost and small sample consumption method for the determination of the volatile and semivolatile constituents in the plant materials.

  1. Heat Transfer and Cooling in Gas Turbines (Le Transfert Thermique et le Refroidissement dans les Turbines a Gaz)

    Science.gov (United States)

    1993-02-01

    transfer coefficient of the problem, unsteady calculations may assuming a composite wall. This simple be required. approach allows the effect of... frottement est utilisd avee un coefficient de valcur bidimensionnelle moyenne v t(2D). En outre, frottement constant. Des lois analytiques d~crivant les la...Diffusion coefficient of Investigation of the flow field near napthalene such junctions are reported by many hm Mass transfer coefficient authors

  2. 改善气液传质的新型表面曝气装置%A Novel Surface Aeration Configuration for Improving Gas-Liquid Mass Transfer

    Institute of Scientific and Technical Information of China (English)

    禹耕之; 毛在砂; 王蓉

    2002-01-01

    A novel surface aeration configuration featured with a self-rotating and floating baffle (SRFB) and a Rnshton disk turbine (DT) with a perforated disk has been developed. The SRFB, consisted of 12 fan blades twisted by an angle of 30° to the horizontal plane, is incorporated onto the impeller shaft to improve gas entrainment, bubble breakup, mixing in a φ154 mm agitated vessel. This new configuration is compared to the conventional DT surface aeration experimentally. The results suggest that the critical impeller speed for onset of gas entrainment is lower for the new configuration and it demands greater power consumption. Moreover, the SRFB system produces 30%-68% higher volumetric mass transfer coefficient per unit power input than that obtained in the conventional DT surface aerator under the same operation conditions.

  3. Electron Transfer Reaction between M-C6H6 and M+-C6H6 Complexes in the Gas Phase: Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    DFT/BLYP method is used to theoretically investigate the electron transfer (ET) reactions between M (Li, Na, Mg)-C6H6 and M+-C6H6 complexes in the gas phase. The geometry optimization of the precursor complexes and the transition state in the process of ET reaction was performed at 6-31G basis set level. The activation energy, the coupling matrix element and the rate constant of the ET reaction are calculated at semi-quantitative level.

  4. Corrosion Control Technique for High-sulphur Gas Gathering and Transferring System in Puguang Gas Field%普光气田集输系统的腐蚀控制技术

    Institute of Scientific and Technical Information of China (English)

    龚金海; 刘德绪; 王晓霖

    2012-01-01

    The gathering and transferring system in Puguang gas-field includes a central gas gathering station and 16 substations covering 38 gas wells and 37.78 km pipelines. The content of hydrogen sulfide in the natural gas is nearly 15%and carbon dioxide from 8% to 10%, so the wet high-sour gas makes great corrosion risk to transferring system. Based on tests of electrochemical corrosion, hydrogen-induced cracking (HIC), sulphide stress cracking (SSC), the materials of anti-sulphide~eorrosion were studied and selected for pipelines and equipment. And injection technique of corrosion inhibitors is used to prevent the pipes from internal corrosion "pre-coating &continuous injecting". Also, cathodic protection and intelligent pigging detection are applied as well. Furthermore, corrosion monitoring techniques including corrosion coupon (CC), electro-resistance (ER), linear polarization resistance (LPR) and field signature method (FSM) are introduced to monitor the corrosion development roundly. The monitoring results show that the average corrosion rate of Puguang gathering and transferring system is limited below 0. 044 ram/a.%普光气田集输系统共建有16座集气站、1座集气总站、38口开发井,站外管线37.78km。由于天然气中硫化氢含量15%左右,二氧化碳含量8%~10%,且采用湿气集输工艺,因此集输系统存在较大腐蚀风险。通过电化学腐蚀试验、抗氢致开裂(HIC)和抗硫化物应力腐蚀(SSC)试验,确定了集输系统抗硫材质,采用“预涂膜+连续注入”的缓蚀剂加注工艺、阴极保护技术和智能清管技术等对设备实施保护。采用腐蚀挂片、电阻探针、线性极化探针和电指纹等多种腐蚀陈测手段。普光气田集输系统腐蚀速率控制在0.044mm/a以下。

  5. Regularities of heat transfer in the gas layers of a steam boiler furnace flame. Part II. Gas layer radiation laws and the procedure for calculating heat transfer in furnaces, fire boxes, and combustion chambers developed on the basis of these laws

    Science.gov (United States)

    Makarov, A. N.

    2014-10-01

    The article presents the results stemming from the scientific discovery of laws relating to radiation from the gas layers generated during flame combustion of fuel and when electric arc burns in electric-arc steel-melting furnaces. The procedure for calculating heat transfer in electric-arc and torch furnaces, fire-boxes, and combustion chambers elaborated on the basis of this discovery is described.

  6. Transference and natural gas distribution system analysis utilizing hybrid modelling; Analise de sistemas de transferencia e distribuicao de gas natural utilizando modelagem hibrida

    Energy Technology Data Exchange (ETDEWEB)

    Calvo, Robson A.; Martinkoski, Ricardo [Centro Federal de Educacao Tecnologica do Parana (CEFET), Curitiba, PR (Brazil); Neves Junior, Flavio [Centro Federal de Educacao Tecnologica do Parana (CEFET), Curitiba, PR (Brazil). Programa de Pos-Graduacao em Engenharia Eletrica e Informatica Industrial

    2003-07-01

    The objective of this article is to apply techniques of formal specification in modelling of natural gas transmission and distribution systems. In this case the formal models are characterized by using hybrid automata. Initially the existent components in the net are modeled and represented by independent hybrid automata. The global dynamics is obtained through the product hybrid automata. Languages representing the desirable states of the system are obtained from the hybrid automata, allowing a hybrid control procedure. An automatic tool as SHIFT must be used to modelling and simulation. (author)

  7. Local effects of ice floes and leads on skin sea surface temperature, mixing and gas transfer in the marginal ice zone

    Science.gov (United States)

    Zappa, Christopher; Brumer, Sophia; Brown, Scott; LeBel, Deborah; McGillis, Wade; Schlosser, Peter; Loose, Brice

    2014-05-01

    Recent years have seen extreme changes in the Arctic. Marginal ice zones (MIZ), or areas where the "ice-albedo feedback" driven by solar warming is highest and ice melt is extensive, may provide insights into the extent of these changes. Furthermore, MIZ play a central role in setting the air-sea CO2 balance making them a critical component of the global carbon cycle. Incomplete understanding of how the sea-ice modulates gas fluxes renders it difficult to estimate the carbon budget in MIZ. Here, we investigate the turbulent mechanisms driving gas exchange in leads, polynyas and in the presence of ice floes using both field and laboratory measurements. Here, we present measurements of visible and IR imagery of melting ice floes in the marginal ice zone north of Oliktok Point AK in the Beaufort Sea made during the Marginal Ice Zone Ocean and Ice Observations and Processes EXperiment (MIZOPEX) in July-August 2013. The visible and IR imagery were taken from the unmanned airborne vehicle (UAV) ScanEagle. The visible imagery clearly defines the scale of the ice floes. The IR imagery show distinct cooling of the skin sea surface temperature (SST) as well as an intricate circulation and mixing pattern that depends on the surface current, wind speed, and near-surface vertical temperature/salinity structure. Individual ice floes develop turbulent wakes as they drift and cause transient mixing of an influx of colder surface (fresh) melt water. We capture a melting and mixing event that explains the changing pattern observed in skin SST and is substantiated using laboratory experiments. The Gas Transfer through Polar Sea Ice experiment was performed at the US Army Cold Regions Research and Engineering Laboratory (Hanover, NH) under varying ice coverage, winds speed, fetch and currents. Supporting measurements were made of air and water temperature, humidity, salinity and wave height. Air-side profiling provided momentum, heat, and CO2 fluxes. Transfer velocities are also

  8. Enhanced lipidic algae biomass production using gas transfer from a fermentative Rhodosporidium toruloides culture to an autotrophic Chlorella protothecoides culture.

    Science.gov (United States)

    Santos, C A; Caldeira, M L; Lopes da Silva, T; Novais, J M; Reis, A

    2013-06-01

    In order to produce single-cell oil for biodiesel, a yeast and a microalga were, for the first time, grown in two separate reactors connected by their gas-phases, taking advantage of their complementary nutritional metabolisms, i.e., respiration and photosynthesis. The yeast Rhodosporidium toruloides was used for lipid production, originating a carbon dioxide-enriched outlet gas stream which in turn was used to stimulate the autotrophic growth of Chlorella protothecoides in a vertical-alveolar-panel (VAP) photobioreactor. The microalgal biomass productivity was 0.015 gL(-1)h(-1), and its lipid productivity attained 2.2 mgL(-1)h(-1) when aerated with the outlet gas stream from the yeast fermenter. These values represent an increase of 94% and 87%, respectively, as compared to a control culture aerated with air. The CO2 bio-fixed by the microalgal biomass reached an estimated value of 29 mgL(-1)h(-1) in the VAP receiving the gas stream from the fermenter, a value 1.9 times higher than that measured in the control VAP.

  9. CFD Study of Full-Scale Aerobic Bioreactors: Evaluation of Dynamic O2 Distribution, Gas-Liquid Mass Transfer and Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Humbird, David; Sitaraman, Hariswaran; Stickel, Jonathan; Sprague, Michael A.; McMillan, Jim

    2016-11-18

    If advanced biofuels are to measurably displace fossil fuels in the near term, they will have to operate at levels of scale, efficiency, and margin unprecedented in the current biotech industry. For aerobically-grown products in particular, scale-up is complex and the practical size, cost, and operability of extremely large reactors is not well understood. Put simply, the problem of how to attain fuel-class production scales comes down to cost-effective delivery of oxygen at high mass transfer rates and low capital and operating costs. To that end, very large reactor vessels (>500 m3) are proposed in order to achieve favorable economies of scale. Additionally, techno-economic evaluation indicates that bubble-column reactors are more cost-effective than stirred-tank reactors in many low-viscosity cultures. In order to advance the design of extremely large aerobic bioreactors, we have performed computational fluid dynamics (CFD) simulations of bubble-column reactors. A multiphase Euler-Euler model is used to explicitly account for the spatial distribution of air (i.e., gas bubbles) in the reactor. Expanding on the existing bioreactor CFD literature (typically focused on the hydrodynamics of bubbly flows), our simulations include interphase mass transfer of oxygen and a simple phenomenological reaction representing the uptake and consumption of dissolved oxygen by submerged cells. The simulations reproduce the expected flow profiles, with net upward flow in the center of column and downward flow near the wall. At high simulated oxygen uptake rates (OUR), oxygen-depleted regions can be observed in the reactor. By increasing the gas flow to enhance mixing and eliminate depleted areas, a maximum oxygen transfer (OTR) rate is obtained as a function of superficial velocity. These insights regarding minimum superficial velocity and maximum reactor size are incorporated into NREL's larger techno-economic models to supplement standard reactor design equations.

  10. Highly regioselective hydride transfer, oxidative dehydrogenation, and hydrogen-atom abstraction in the thermal gas-phase chemistry of [Zn(OH)](+)/C3H8.

    Science.gov (United States)

    Wu, Xiao-Nan; Zhao, Hai-Tao; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2014-12-28

    The thermal reactions of [Zn(OH)](+) with C3H8 have been studied by means of gas-phase experiments and computational investigation. Two types of C-H bond activation are observed in the experiment, and pertinent mechanistic features include inter alia: (i) the metal center of [Zn(OH)](+) serves as active site in the hydride transfer to generate [i-C3H7](+) as major product, (ii) generally, a high regioselectivity is accompanied by remarkable chemoselectivity: for example, the activation of a methyl C-H bond results mainly in the formation of water and [Zn(C3,H7)](+). According to computational work, this ionic product corresponds to [HZn(CH3CH=CH2)](+). Attack of the zinc center at a secondary C-H bond leads preferentially to hydride transfer, thus giving rise to the generation of [i-C3H7](+); (iii) upon oxidative dehydrogenation (ODH), liberation of CH3CH2=CH2 occurs to produce [HZn(H2O)](+). Both, ODH as well as H2O loss proceed through the same intermediate which is characterized by the fact that a methylene hydrogen atom from the substrate is transferred to the zinc and one hydrogen atom from the methyl group to the OH group of [Zn(OH)](+). The combined experimental/computational gas-phase study of C-H bond activation by zinc hydroxide provides mechanistic insight into related zinc-catalyzed large-scale processes and identifies the crucial role that the Lewis-acid character of zinc plays.

  11. Power Consumption, Mixing Time, and Oxygen Mass Transfer in a Gas-Liquid Contactor Stirred with a Dual Impeller for Different Spacing

    Directory of Open Access Journals (Sweden)

    Hayder Mohammed Issa

    2016-01-01

    Full Text Available Multiple or dual impellers are widely implemented in stirred contactors used in various biological processes like fermentation, water treatment, and pharmaceutical production. The spacing between impellers is considered as a crucial factor in designing of these types of contactors resulting in variation of oxygen mass transfer, mixing time, or power consumption for such biological system. A study of three parts was conducted to characterize the effect of the spacing between impellers on the most important parameters that related to biological contactor performance: oxygen mass transfer coefficient kla from the gas phase (air to the liquid phase (water, mixing time, and power consumption for different operating rotational speeds (1.67–3.33 rps and for three different spacing positions. The used impellers system in the study is a dual impeller system which consists of an inverted and bladed rotated cone (IBRC and a pitched-blade up-flow propeller (PBPU. The experimental results showed that the shorter spacing (the lower PBPU in a higher position is more convenient, as the achieved oxygen mass transfer coefficient has showed an improvement in its values with lower mixing time and with a slight alteration in power consumption.

  12. Modeling of gas-liquid mass transfer in a stirred tank bioreactor agitated by a Rushton turbine or a new pitched blade impeller.

    Science.gov (United States)

    Gelves, Ricardo; Dietrich, A; Takors, Ralf

    2014-03-01

    A combined computational fluid dynamics (CFD) and population balance model (PBM) approach has been applied to simulate hydrodynamics and mass transfer in a 0.18 m(3) gas-liquid stirred bioreactor agitated by (1) a Rushton turbine, and (2) a new pitched blade geometry with rotating cartridges. The operating conditions chosen were motivated by typical settings used for culturing mammalian cells. The effects of turbulence, rotating flow, bubbles breakage and coalescence were simulated using the k-ε, multiple reference frame (MRF), Sliding mesh (SM) and PBM approaches, respectively. Considering the new pitched blade geometry with rotating aeration microspargers, [Formula: see text] mass transfer was estimated to be 34 times higher than the conventional Rushton turbine set-up. Notably, the impeller power consumption was modeled to be about 50 % lower. Independent [Formula: see text] measurements applying the same operational conditions confirmed this finding. Motivated by these simulated and experimental results, the new aeration and stirring device is qualified as a very promising tool especially useful for cell culture applications which are characterized by the challenging problem of achieving relatively high mass transfer conditions while inserting only low stirrer energy.

  13. Flow and heat and mass transfer in laminar and turbulent mist gas-droplets stream over a flat plate

    CERN Document Server

    Terekhov, Victor I

    2014-01-01

    In this book the author presents selected challenges of thermal-hydraulics modeling of two-phase flows in minichannels with change of phase. These encompass the common modeling of flow boiling and flow condensation using the same expression. Approaches to model these two respective cases show, however, that experimental data show different results to those obtained by methods of calculation of heat transfer coefficient for respective cases. Partially that can be devoted to the fact that there are non-adiabatic effects present in both types of phase change phenomena which modify the pressure drop due to friction, responsible for appropriate modelling. The modification of interface shear stresses between flow boiling and flow condensation in case of annular flow structure may be considered through incorporation of the so called blowing parameter, which differentiates between these two modes of heat transfer. On the other hand, in case of bubbly flows, the generation of bubbles also modifies the friction pressur...

  14. Hollow fiber membrane based H-2 diffusion for efficient in situ biogas upgrading in an anaerobic reactor

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2013-01-01

    Bubbleless gas transfer through a hollow fiber membrane (HFM) module was used to supply H2 to an anaerobic reactor for in situ biogas upgrading, and it creates a novel system that could achieve a CH4 content higher than 90 % in the biogas. The increase of CH4 content and pH, and the decrease of b...... also demonstrated that the biofilm formed on the membrane only contributed 22-36 % to the H2 consumption, while most of the H2 was consumed by the microorganisms in the liquid phase....

  15. Convective heat-transfer rate distributions over a 140 deg blunt cone at hypersonic speeds in different gas environments

    Science.gov (United States)

    Stewart, David A.; Chen, Y. K.

    1993-01-01

    Experiments were conducted in air, CO2, and CO2-argon gas mixtures to obtain heating distribution data over a 140 deg blunt cone with various corner radii. The effect of corner radius on the heating distribution over the forebody of the cone was included in the investigation. These experiments provide data for validation of two-dimensional axisymmetric and three-dimensional Navier-Stokes solutions. Heating distribution data and measured bow shock wave stand-off distances for 0 deg angle of attack were compared with predicted values using a two-dimensional axisymmetric Navier-Stokes code.

  16. Oceanic whitecaps: Sea surface features detectable via satellite that are indicators of the magnitude of the air-sea gas transfer coefficient

    Indian Academy of Sciences (India)

    E C Monahan

    2002-09-01

    Stage A whitecaps (spilling wave crests) have a microwave emissivity of close to 1. Thus if even a small fraction of the sea surface is covered by these features there will be a detectable enhancement in the apparent microwave brightness temperature of that surface as determined by satellite-borne microwave radiometers. This increase in the apparent microwave brightness temperature can as a consequence be routinely used to estimate the fraction of the sea surface covered by stage A whitecaps. For all but the very lowest wind speeds it has been shown in a series of controlled experiments that the air-sea gas transfer coeffcient for each of a wide range of gases, including carbon dioxide and oxygen, is directly proportional to the fraction of the sea surface covered by these stage A whitecaps.

  17. Loss of ammonia during electron-transfer dissociation of deuterated peptides as an inherent gauge of gas-phase hydrogen scrambling

    DEFF Research Database (Denmark)

    Rand, Kasper D; Zehl, Martin; Jensen, Ole Nørregaard;

    2010-01-01

    detected by a depletion of deuterium when deuterated ammonia is lost from peptides during ETD. This straightforward method requires no modifications to the experimental workflow and has the great advantage that the occurrence of hydrogen scrambling can be directly detected in the actual peptides analyzed......The application of electron-transfer dissociation (ETD) to obtain single-residue resolution in hydrogen exchange-mass spectrometry (HX-MS) experiments has recently been demonstrated. For such measurements, it is critical to ensure that the level of gas-phase hydrogen scrambling is negligible. Here...... we utilize the abundant loss of ammonia upon ETD of peptide ions as a universal reporter of positional randomization of the exchangeable hydrogens (hydrogen scrambling) during HX-ETD experiments. We show that the loss of ammonia from peptide ions proceeds without depletion of deuterium when employing...

  18. The collisional energy transfer between the D1Π and d3Π states of the NaK dimer induced by argon buffer gas

    Science.gov (United States)

    Zhiwei, Huang; Teck Chee, Chia; Cheong Hoong, Diong; Sing, Lee; Wei, Zheng; Jinkai, Chen

    1998-04-01

    By using the 514.5 nm line of a cw argon-ion laser, the discrete spectrum of D1@MX1D+ transitions and the continuum spectrum of d3@Ma3D+ transitions of the NaK dimer in a heat pipe could be observed in the range of 500-700 nm. The collision-induced enhancement effects of the intensities IdMa and the quenching effect of the intensities IDMX by collisions with argon buffer gas at different pressures were measured experimentally. Based on the stationary collisional model and lifetime measurements, the quenching cross sections and cross sections for collision-induced energy transfer between the D1@ and d3@ states could be estimated.

  19. Numerical and Experimental Modelling of Gas Flow and Heat Transfer in the Air Gap of an Electric Machine. Part Ⅱ: Grooved Surfaces

    Institute of Scientific and Technical Information of China (English)

    Maunu KUOSA; Petri SALLINEN; Arttu REUNANEN; Jari BACKMAN; Jaakko LARJOLA; Lasse KOSKELAINEN

    2005-01-01

    The study deals with the cooling of a high-speed electric machine through an air gap with numerical and experimental methods. The rotation speed of the test machine is between 5000~40000 r/min and the machine is cooled by a forced gas flow through the air gap. In the previous part of the research the friction coefficient was measured for smooth and grooved stator cases with a smooth rotor. The heat transfer coefficient was recently calculated by a numerical method and measured for a smooth stator-rotor combination. In this report the cases with axial groove slots at the stator and/or rotor surfaces are studied. Numerical flow simulations and measurements have been done for the test machine dimensions at a large velocity range. At constant mass flow rate the heat transfer coefficients by the numerical method attain bigger values with groove slots on the stator or rotor surfaces. The results by the numerical method have been confirmed with measurements. The RdF-sensor was glued to the stator and rotor surfaces to measure the heat flux through the surface, as well as the temperature.

  20. Calculations of non-gray gas radiative heat transfer by coupling the discrete ordinates method with the Leckner model in 3D rectangular enclosures

    Science.gov (United States)

    Fathi Azarkhavarani, M. E.; Hosseini Abardeh, R.; Rahmani, M.

    2015-12-01

    In this study a new approach for radiation heat flux calculations by coupling the discrete ordinates method with the Leckner global model is introduced. The aim is to analyze the radiative heat transfer problem within a three-dimensional enclosure filled with non-gray gas mixture of H2O and CO2 . A computer code developed by this approach is applied to radiative calculations in three groups of well-known test cases published previously; considering homogeneous and inhomogeneous isothermal and non-isothermal participating media. All results are compared with well-known calculations based on statistical narrow band model. Also a new series of predictions for a medium with non-black walls and various mixture of H2O and CO2 is performed to demonstrate the applicability of the Leckner model. The effect of different compositions of H2O and CO2 on the radiative transfer within modern combustors is also examined. Based on the results obtained, it is believed that the discrete ordinates method coupled with the Leckner global model despite of its inherent simplicity and low computational cost is sufficiently accurate. For its convenient use, this method is suitable for a wide range of engineering calculations of participating media as well as for its link to previously written computational fluid dynamics codes.

  1. Intermolecular hydrogen transfer between guest species in small and large cages of methane + propane mixed gas hydrates.

    Science.gov (United States)

    Sugahara, Takeshi; Kobayashi, Yusuke; Tani, Atsushi; Inoue, Tatsuya; Ohgaki, Kazunari

    2012-03-15

    To investigate the molecular interaction between guest species inside of the small and large cages of methane + propane mixed gas hydrates, thermal stabilities of the methyl radical (possibly induced in small cages) and the normal propyl and isopropyl radicals (induced in large cages) were investigated by means of electron spin resonance measurements. The increase of the total amount of the normal propyl and isopropyl radicals reveals that the methyl radical in the small cage withdraws one hydrogen atom from the propane molecule enclathrated in the adjacent large cage of the structure-II hydrate. A guest species in a hydrate cage has the ability to interact closely with the other one in the adjacent cages. The clathrate hydrate may be utilized as a possible nanoscale reaction field.

  2. Analysis of conjugated heat transfer, in transient state of the first stage of a gas turbine; Analisis de transferencia de calor conjugada, en estado transitorio, de la primera etapa de una turbina de gas

    Energy Technology Data Exchange (ETDEWEB)

    Campos Amezcua, Alfonso; Mazur C, Zdzislaw [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Gallegos Munoz, Armando [Facultad de Ingenieria Mecanica, Electrica y Electronica (FIMEE), Universidad de Guanajuato, Guanajuato (Mexico)

    2007-11-15

    This article presents an analysis of conjugated heat transfer in the first stage of movable blades during the starting of a gas turbine, covering a period of 1,012 seconds. The developed computer model is in 3D and uses as initial and border conditions typical starting curves for stack gases, the cooling air and the angular velocity of the blades. As a result of the numerical predictions, the temperature distributions in stack gases, the trowel of the blade and the cooling air are included, doing emphasis in the results obtained in the solid (body of the blade), since these are used for thermo-mechanical stress analysis and later estimation of the blade residual life. [Spanish] Este articulo presenta un analisis de transferencia de calor conjugada en la primera etapa de alabes moviles, durante el arranque de una turbina de gas, cubriendo un periodo de 1.012 segundos. El modelo computacional desarrollado es en tres dimensiones y utiliza como condiciones iniciales y de frontera curvas de arranque tipicas para los gases de combustion, el aire de enfriamiento y la velocidad angular de los alabes. Como resultado de las predicciones numericas, se incluyen las distribuciones de temperatura en los gases de combustion, la paleta del alabe y el aire de enfriamiento, haciendo enfasis en los resultados obtenidos en el solido (cuerpo del alabe), ya que estos se utilizan para analisis de esfuerzos termomecanicos y posterior estimacion de vida residual del alabe.

  3. MHD free convection flow of a visco-elastic (Kuvshiniski type dusty gas through a semi infinite plate moving with velocity decreasing exponentially with time and radiative heat transfer

    Directory of Open Access Journals (Sweden)

    Om Prakash

    2011-06-01

    Full Text Available The present paper is concerned with the study of MHD free convective flow of a visco-elastic (Kuvshinski type dusty gas through a porous medium induced by the motion of a semi-infinite flat plate under the influence of radiative heat transfer moving with velocity decreasing exponentially with time. The expressions for velocity distribution of a dusty gas and dust particles, concentration profile and temperature field are obtained. The effect of Schmidt number (Sc, Magnetic field parameter (M and Radiation parameter (N on velocity distribution of dusty gas and dust particles, concentration and temperature distribution are discussed graphically.

  4. Effects of high free-flow turbulence, intensive cooling, and wake on the external heat transfer of a gas turbine blade with external heat transfer. Zum Einfluss hoher Freistromturbulenz, intensiver Kuehlung und einer Nachlaufstroemung auf den aeusseren Waermeuebergang einer konvektiv gekuehlten Gasturbinenschaufel

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, A.V.

    1986-04-18

    The effects of free flow turbulence on the heat transfer characteristics of a gas turbine blade with convective cooling are investigated in hot-gas conditions, making a rigid distribution between isotropic turbulence and the free laminar turbulence of a wake flow. The influence of different Reynolds numbers of the grid flow and of different degrees of surface cooling is determined by means of heat transfer experiments with isotropic turbulence generated by quadratic grids. Experimental heat transfer data are compared with the results of a difference boundary layer calculation. The free flow turbulence is determined by laser doppler anemometry while the temperature field is calculated by a finite element method with experimentally determined boundary conditions. Another factor investigated was the effect of a wake on the heat transfer along the blade surface. A turbulent wake was simulated and discussed. (HAG).

  5. 土壤气相抽提过程非水相液体与气相的传质动力学研究%Kinetic Mass Transfer Between Non-aqueous Phase Liquid and Gas During Soil Vapor Extraction

    Institute of Scientific and Technical Information of China (English)

    李鑫钢; 黄国强; 沈铁孟

    2002-01-01

    The mass transfer between non-aqueous phase liquid(NAPL) phase and soil gas phase in soil vapor extraction(SVE) process has been investigated by one-dimensional venting experiments. During quasi-steady volatilization of three single-component NAPLs in a sandy soil, constant initial lumped mass transfer coefficient (λgN,0) canbe obtained if the relative saturation (ξ) between NAPL phase and gas phase is higher than a critical value (ξc), andthe lumped mass transfer coefficient decreases with ξ when ξ<ξc. It is also shown that the lumped mass transfercoefficient can be increased by blending porous micro-particles into the sandy soil because of the increasing of theinterfacial area.

  6. Flue gas condensation in oxyfuel power plants. Heat- and mass transfer measurements and experimental validation of an efficient condensation concept; Rauchgaskondensation in Oxyfuel-Kraftwerken. Waerme- und Stoffuebergangsmessungen sowie experimentelle Validierung eines effizienten Kondensationskonzepts

    Energy Technology Data Exchange (ETDEWEB)

    Raindl, Markus

    2010-12-06

    Condensation of a steam-inert gas mixture in an Oxyfuel condenser differs significantly from condensation of pure steam: condenser pressure and rest gas content increase dramatically, heat- and mass transfer coefficients are lower and oversaturation of the steam-inert gas mixture yields to fog formation. In the context of this thesis, therefore, at first the optimal ranges of working parameters for Oxyfuel processes calculated. In the following some heat flux measurements were carried out on a horizontal, crossflow pipe to validate various heat- and mass transfer theories. Building on these results a new, efficient condensation concept was developed to reduce fog formation. The final results of the measurements with a laboratory model show great performance regarding fog reduction and condensation efficiency. (orig.)

  7. Effects of total pressure on non-grey gas radiation transfer in oxy-fuel combustion using the LBL, SNB, SNBCK, WSGG, and FSCK methods

    Science.gov (United States)

    Chu, Huaqiang; Gu, Mingyan; Consalvi, Jean-Louis; Liu, Fengshan; Zhou, Huaichun

    2016-03-01

    The effects of total pressure on gas radiation heat transfer are investigated in 1D parallel plate geometry containing isothermal and homogeneous media and an inhomogeneous and non-isothermal CO2-H2O mixture under conditions relevant to oxy-fuel combustion using the line-by-line (LBL), statistical narrow-band (SNB), statistical narrow-band correlated-k (SNBCK), weighted-sum-of-grey-gases (WSGG), and full-spectrum correlated-k (FSCK) models. The LBL calculations were conducted using the HITEMP2010 and CDSD-1000 databases and the LBL results serve as the benchmark solution to evaluate the accuracy of the other models. Calculations of the SNB, SNBCK, and FSCK were conducted using both the 1997 EM2C SNB parameters and their recently updated 2012 parameters to investigate how the SNB model parameters affect the results under oxy-fuel combustion conditions at high pressures. The WSGG model considered is the recently developed one by Bordbar et al. [19] for oxy-fuel combustion based on LBL calculations using HITEMP2010. The total pressure considered ranges from 1 up to 30 atm. The total pressure significantly affects gas radiation transfer primarily through the increase in molecule number density and only slightly through spectral line broadening. Using the 1997 EM2C SNB model parameters the accuracy of SNB and SNBCK is very good and remains essentially independent of the total pressure. When using the 2012 EM2C SNB model parameters the SNB and SNBCK results are less accurate and their error increases with increasing the total pressure. The WSGG model has the lowest accuracy and the best computational efficiency among the models investigated. The errors of both WSGG and FSCK using the 2012 EM2C SNB model parameters increase when the total pressure is increased from 1 to 10 atm, but remain nearly independent of the total pressure beyond 10 atm. When using the 1997 EM2C SNB model parameters the accuracy of FSCK only slightly decreases with increasing the total pressure.

  8. Effect of gas-transfer velocity parameterization choice on air-sea CO2 fluxes in the North Atlantic Ocean and the European Arctic

    Science.gov (United States)

    Wrobel, Iwona; Piskozub, Jacek

    2016-09-01

    The oceanic sink of carbon dioxide (CO2) is an important part of the global carbon budget. Understanding uncertainties in the calculation of this net flux into the ocean is crucial for climate research. One of the sources of the uncertainty within this calculation is the parameterization chosen for the CO2 gas-transfer velocity. We used a recently developed software toolbox, called the FluxEngine (Shutler et al., 2016), to estimate the monthly air-sea CO2 fluxes for the extratropical North Atlantic Ocean, including the European Arctic, and for the global ocean using several published quadratic and cubic wind speed parameterizations of the gas-transfer velocity. The aim of the study is to constrain the uncertainty caused by the choice of parameterization in the North Atlantic Ocean. This region is a large oceanic sink of CO2, and it is also a region characterized by strong winds, especially in winter but with good in situ data coverage. We show that the uncertainty in the parameterization is smaller in the North Atlantic Ocean and the Arctic than in the global ocean. It is as little as 5 % in the North Atlantic and 4 % in the European Arctic, in comparison to 9 % for the global ocean when restricted to parameterizations with quadratic wind dependence. This uncertainty becomes 46, 44, and 65 %, respectively, when all parameterizations are considered. We suggest that this smaller uncertainty (5 and 4 %) is caused by a combination of higher than global average wind speeds in the North Atlantic (> 7 ms-1) and lack of any seasonal changes in the direction of the flux direction within most of the region. We also compare the impact of using two different in situ pCO2 data sets (Takahashi et al. (2009) and Surface Ocean CO2 Atlas (SOCAT) v1.5 and v2.0, for the flux calculation. The annual fluxes using the two data sets differ by 8 % in the North Atlantic and 19 % in the European Arctic. The seasonal fluxes in the Arctic computed from the two data sets disagree with each

  9. Simultaneous determination of benzene and phenol in heat transfer fluid by head-space gas chromatography hyphenated with ion mobility spectrometry.

    Science.gov (United States)

    Criado-García, L; Garrido-Delgado, R; Arce, L; López, F; Peón, R; Valcárcel, M

    2015-11-01

    The quantitative determination of some compounds such as benzene and phenol in a complex matrix by ion mobility spectrometry (IMS) can be a difficult task, due to the influence of other components present in the matrix and the chemical properties of both compounds, such as their high volatility and low proton affinity. Monitoring of these compounds in a heat transfer fluid (HTF) is essential to check the correct working of a thermosolar plant and for safety and environmental reasons. Benzene and phenol, among other compounds, are produced when HTF is exposed to high temperatures in continuous cycles and their presence can decrease the efficiency of HTF. For the first time, a headspace module coupled to a gas chromatography column in combination with an IMS (with a tritium ionization source) has been optimized and fully validated to simultaneously quantify benzene and phenol in HTF. The limit of detection (LOD) and limit of quantification (LOQ) achieved with the method proposed were 0.011 and 0.038 g L(-1) and 0.004 and 0.014 g L(-1) for benzene and phenol respectively. The precision of the method was evaluated in terms of repeatability and reproducibility with all values lower than 9.2% and 13.3%, respectively. Results demonstrated that benzene and phenol were generated in the HTF heating process, and its concentration increased with heating time (approximately 483 h). The average concentration values for benzene and phenol in degraded HTF samples were not significantly different to values obtained using a gas chromatography-flame ionization detector instrument. Therefore, IMS is a promising technique for in-field quality control of HTF in a thermosolar plant due to its speed, versatility, sensitivity and selectivity to quantify these degradation compounds.

  10. Structure Segmentation and Transfer Faults in the Marcellus Shale, Clearfield County, Pennsylvania: Implications for Gas Recovery Efficiency and Risk Assessment Using 3D Seismic Attribute Analysis

    Science.gov (United States)

    Roberts, Emily D.

    The Marcellus Shale has become an important unconventional gas reservoir in the oil and gas industry. Fractures within this organic-rich black shale serve as an important component of porosity and permeability useful in enhancing production. Horizontal drilling is the primary approach for extracting hydrocarbons in the Marcellus Shale. Typically, wells are drilled perpendicular to natural fractures in an attempt to intersect fractures for effective hydraulic stimulation. If the fractures are contained within the shale, then hydraulic fracturing can enhance permeability by further breaking the already weakened rock. However, natural fractures can affect hydraulic stimulations by absorbing and/or redirecting the energy away from the wellbore, causing a decreased efficiency in gas recovery, as has been the case for the Clearfield County, Pennsylvania study area. Estimating appropriate distances away from faults and fractures, which may limit hydrocarbon recovery, is essential to reducing the risk of injection fluid migration along these faults. In an attempt to mitigate the negative influences of natural fractures on hydrocarbon extraction within the Marcellus Shale, fractures were analyzed through the aid of both traditional and advanced seismic attributes including variance, curvature, ant tracking, and waveform model regression. Through the integration of well log interpretations and seismic data, a detailed assessment of structural discontinuities that may decrease the recovery efficiency of hydrocarbons was conducted. High-quality 3D seismic data in Central Pennsylvania show regional folds and thrusts above the major detachment interval of the Salina Salt. In addition to the regional detachment folds and thrusts, cross-regional, northwest-trending lineaments were mapped. These lineaments may pose a threat to hydrocarbon productivity and recovery efficiency due to faults and fractures acting as paths of least resistance for induced hydraulic stimulation fluids

  11. Trace gas detection from fermentation processes in apples; an intercomparison study between proton-transfer-reaction mass spectrometry and laser photoacoustics

    Science.gov (United States)

    Boamfa, E. I.; Steeghs, M. M. L.; Cristescu, S. M.; Harren, F. J. M.

    2004-12-01

    A custom-built proton-transfer-reaction mass spectrometry (PTR-MS) instrument was used to monitor the emission of various compounds (aldehydes, alcohols, acids, acetates and C-6 compounds) related to fermentation, aroma and flavour, released by four apple cultivars (Elstar, Jonaglod, Granny Smith and Pink Lady) under short anaerobic (24 h) and post-anaerobic conditions. The novel feature of our instrument is the new design of the collisional dissociation chamber, which separates the high pressure in the drift tube (2 mbar) from the high vacuum pressure in the detection region (10-6 mbar). The geometry of this chamber was changed and a second turbo pump was added to reduce the influence of collisional loss of ions, background signals and cluster ions, which facilitates the interpretation of the mass spectra and increases the signal intensity at the mass of the original protonated compound. With this system, detection limits of similar magnitude to the ones reported in literature are reached. An intercomparison study between PTR-MS and a CO laser-based photoacoustic trace gas detector is presented. The alcoholic fermentation products (acetaldehyde and ethanol) from young rice plants were simultaneously monitored by both methods. A very good agreement was observed for acetaldehyde production. The photoacoustic detector showed about two times lower ethanol concentration as compared to PTR-MS, caused by memory effects due to sticking of compounds to the walls of the nylon tube used to transport the trace gases to the detector.

  12. Gas-liquid transfer data used to analyze hydrophobic hydration and find the nature of the Kauzmann-Tanford hydrophobic factor

    OpenAIRE

    Baldwin, Robert L.

    2012-01-01

    Hydrophobic free energy for protein folding is currently measured by liquid-liquid transfer, based on an analogy between the folding process and the transfer of a nonpolar solute from water into a reference solvent. The second part of the analogy (transfer into a nonaqueous solvent) is dubious and has been justified by arguing that transfer out of water probably contributes the major part of the free energy change. This assumption is wrong: transfer out of water contributes no more than half ...

  13. Simple setup for gas-phase h/d exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale

    DEFF Research Database (Denmark)

    Mistarz, Ulrik Hvid; Brown, Jeffery M; Haselmann, Kim F

    2014-01-01

    inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated....../D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium...... separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow....

  14. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption is a new, efficient and flexible way to carry out gas-liquid contacting operations with hollow fibre membranes. Advantages of gas absorption membranes over conventional G-L contactors are: -High specific surface area and rapid mass transfer resulting in very compact and low w

  15. 接触式烟气冷凝换热器的换热性能%Heat transfer performance of direct-contact flue-gas condensation heat exchanger

    Institute of Scientific and Technical Information of China (English)

    刘华; 周贤; 付林

    2014-01-01

    Based on the analytical solution of heat-mass transfer fundamental formula between flue-gas and water surface,analyses the key influencing factors on heat transfer efficiency of flue-gas and water. The results show that the main influencing factors are the water-gas ratio,height of heat exchanger and sprayed water droplet diameter.However,velocity of gas influences less.Sets up the performance test-bed for boiler flue-gas heat recovery,and verifies the results of theoretical calculation.%通过求解烟气与水表面之间的热质交换基本方程,得出了烟气与水换热的解析解,并分析了接触式烟气与水处理过程热质交换性能的影响因素。结果表明,烟气与水换热效率的主要影响因素是水气比、换热器高度、喷水雾化粒径,而烟气流速的影响相对较小。搭建了锅炉烟气余热回收实验台,验证了理论计算结果的正确性。

  16. Deactivation of CO(v = 1) by n-H/sub 2/ and n-D/sub 2/ in liquid Ar: a comparison with energy transfer in the gas phase

    Energy Technology Data Exchange (ETDEWEB)

    Lupo, D.W.; Lucas, D.

    1986-10-09

    The rate coefficients for deactivation of vibrationally excited CO by n-H/sub 2/ and n-D/sub 2/ in liquid Ar at 87 K are reported. The results are compared with the measurements for the same processes in the gas phase at low temperature; the rate coefficients are found to be approximately equal in the two phases. These results are compared with the predictions of the isolated binary interaction (IBI) model, which predicts that the energy-transfer rate should be approximately 3 times larger in the liquid phase than in the gas phase for a given concentration of hydrogen or deuterium. Some possible reasons for the discrepancy are discussed.

  17. Measurements of acetone and other gas phase product yields from the OH-initiated oxidation of terpenes by proton-transfer-reaction mass spectrometry (PTR-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Wisthaler, A.; Lindinger, W. [University of Innsbruck (Austria). Institut fuer Ionenphysik; Jensen, N.R.; Winterhalter, R.; Hjorth, J. [Joint Research Centre, European Commission, Environment Institute, Ispra (Italy)

    2001-07-01

    The atmospheric oxidation of several terpenes appears to be a potentially relevant source of acetone in the atmosphere. Proton-transfer-reaction mass spectrometry was used as an on-line analytical method in a chamber study to measure acetone and other gas phase products from the oxidation of {alpha}- and {beta}-pinene initiated by OH radicals in air and in the presence of NO{sub x}. Acetone may be formed promptly, following attack by the OH radical on the terpene, via a series of highly unstable radical intermediates. It can also be formed by slower processes, via degradation of stable non-radical intermediates such as pinonaldehyde and nopinone. Primary acetone and pinonaldehyde molar yields of 11{+-}2% (one {sigma}) and 34{+-}9% (one {sigma}), respectively, were found from the reaction between {alpha}-pinene and the OH radical. After all {alpha}-pinene had been consumed, an additional formation of acetone due to the degradation of stable non-radical intermediates was observed. The total amount of acetone formed was 15{+-}2% (one {sigma}) of the reacted {alpha}-pinene. An upper limit of 12{+-}3% (one {sigma}) for the acetone molar yield from the oxidation of pinonaldehyde was established. From the reaction between {beta}-pinene and the OH radicals, primary acetone and nopinone molar yields of 13{+-}2% (one {sigma}) and 25{+-}3% (one {sigma}), respectively, were observed. Additional amounts of acetone were formed by the further degradation of the primary product, such as the most abundant product nopinone. The total amount of acetone formed was 16{+-}2% (one {sigma}) of the reacted {beta}-pinene. An upper limit of 12{+-}2% (one {sigma}) for the acetone molar yield from the oxidation of nopinone was established. The observed product yields from {alpha}- and {beta}-pinene are in good agreement with other studies using mass-spectrometric and gas chromatographic analytical techniques, but differ significantly from previous studies using spectroscopic methods. Possible

  18. Buoyancy-Driven Heat Transfer During Application of a Thermal Gradient for the Study of Vapor Deposition at Low Pressure Using and Ideal Gas

    Science.gov (United States)

    Frazier, D. O.; Hung, R. J.; Paley, M. S.; Penn, B. G.; Long, Y. T.

    1996-01-01

    A mathematical model has been developed to determine heat transfer during vapor deposition of source materials under a variety of orientations relative to gravitational accelerations. The model demonstrates that convection can occur at total pressures as low as 10-2 mm Hg. Through numerical computation, using physical material parameters of air, a series of time steps demonstrates the development of flow and temperature profiles during the course of vapor deposition. These computations show that in unit gravity vapor deposition occurs by transport through a fairly complicated circulating flow pattern when applying heat to the bottom of the vessel with parallel orientation with respect to the gravity vector. The model material parameters for air predict the effect of kinematic viscosity to be of the same order as thermal diffusivity, which is the case for Prandtl number approx. 1 fluids. Qualitative agreement between experiment and the model indicates that 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-l-ol (DAMNA) at these pressures indeed approximates an ideal gas at the experiment temperatures, and may validate the use of air physical constants. It is apparent that complicated nonuniform temperature distribution in the vapor could dramatically affect the homogeneity, orientation, and quality of deposited films. The experimental test i's a qualitative comparison of film thickness using ultraviolet-visible spectroscopy on films generated in appropriately oriented vapor deposition cells. In the case where heating of the reaction vessel occurs from the top, deposition of vapor does not normally occur by convection due to a stable stratified medium. When vapor deposition occurs in vessels heated at the bottom, but oriented relative to the gravity vector between these two extremes, horizontal thermal gradients induce a complex flow pattern. In the plane parallel to the tilt axis, the flow pattern is symmetrical and opposite in direction from that where the vessel is

  19. Electron transfer reactions

    CERN Document Server

    Cannon, R D

    2013-01-01

    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  20. Homogenization of some radiative heat transfer models: application to gas-cooled reactor cores; Homogeneisation de modeles de transferts thermiques et radiatifs: application au coeur des reacteurs a caloporteur gaz

    Energy Technology Data Exchange (ETDEWEB)

    El Ganaoui, K

    2006-09-15

    In the context of homogenization theory we treat some heat transfer problems involving unusual (according to the homogenization) boundary conditions. These problems are defined in a solid periodic perforated domain where two scales (macroscopic and microscopic) are to be taken into account and describe heat transfer by conduction in the solid and by radiation on the wall of each hole. Two kinds of radiation are considered: radiation in an infinite medium (non-linear problem) and radiation in cavity with grey-diffuse walls (non-linear and non-local problem). The derived homogenized models are conduction problems with an effective conductivity which depend on the considered radiation. Thus we introduce a framework (homogenization and validation) based on mathematical justification using the two-scale convergence method and numerical validation by simulations using the computer code CAST3M. This study, performed for gas cooled reactors cores, can be extended to other perforated domains involving the considered heat transfer phenomena. (author)

  1. Numerical Research of External Heat Transfer for Heavy Gas Turbine Blade%重型燃机透平叶片外壁面换热的数值研究

    Institute of Scientific and Technical Information of China (English)

    慕粉娟; 王思远

    2015-01-01

    开发了重型燃机叶片的外换热及气膜修正程序,对某重型燃机的透平第一级静叶片进行了外换热计算,并针对有气膜冷却的叶片对外换热系数进行了修正,分析了不同截面叶型的换热系数分布和湍流度对换热的影响,同时对比了气膜修正前后的换热系数,得到了叶片外部换热特点。%This article developed the external heat transfer program for heavy gas turbine blade ,and calculated the EHTC (external heat transfer coefficients) of some heavy gas turbine first stage stator blade ,corrected the EHTC with the air-film correction program. The distribution of the HTC along the blade profile on different sections was analyzed. The effect of the turbulence intensity on the heat transfer was also discussed. The HTC before and after air-film corrected was compared. Thus, we got the external heat transfer characteristics of blade.

  2. Study on the Principle Mechanisms of Heat Transfer for Cryogenic Insulations: Especially Accounting for the Temperature-Dependent Deposition-Evacuation of the Filling Gas (Self-Evacuating Systems)

    Science.gov (United States)

    Geisler, Matthias; Vidi, Stephan; Ebert, Hans-Peter

    2016-11-01

    This study concentrates on the principles of heat transfer within cryogenic insulation systems, especially accounting for self-evacuating systems (deposition-evacuation of the filling gas). These principles allow the extrapolation to other temperatures, gases and other materials with the input of only a few experimentally derived or carefully estimated material properties. The type of gas (e.g. air or CO2) within the porous insulation material dominates the behaviour of the effective thermal conductivity during the cooldown of the cryogenic application. This is due to the specific temperature-dependent saturation gas pressure which determines the contribution of the gas conductivity. The selected material classes include powders, fibrous insulations, foams, aerogels and multilayer insulations in the temperature range of 20 K to 300 K. Novel within this study is an analytical function for the total and the mean thermal conductivity with respect to the temperature, type of gas, external pressure and material class of the insulation. Furthermore, the integral mean value of the thermal conductivity, the so-called mean thermal conductivity, is calculated for a mechanically evacuated insulation material and an insulation material evacuated by deposition-evacuation of the filling gas, respectively. This enables a comparison of the total thermal conductivity of cryogenic insulation materials and their applicability for a self-evacuating cryogenic insulation system.

  3. Prediction of Core-Annulus Solids Mass Transfer Coefficient in Gas-Solid Fluidized Bed Risers%气固循环流化床提升管环核区颗粒质量传递系数的估计

    Institute of Scientific and Technical Information of China (English)

    刘新华; 高士秋; 宋文立

    2005-01-01

    Based on analysis of energy dissipation in the core region of gas-solid fluidized bed risers, a simplified model for determination of core-annulus solids mass transfer coefficient was developed according to turbulent diffusion mechanism of particles. The simulation results are consistent with published experimental data. Core-annulus solids mass transfer coefficient decreases with increasing particle size, particle density and solids circulation rate,but generally increases with increasing superficial gas velocity and riser diameter. In the upper dilute region of gas-solid fluidized bed risers, core-annulus solids mass transfer coefficient was found to change little with the axial coordinate in the bed.

  4. A Three-dimensional Heterogeneous Mass Transfer Model for the Absorption of Gas into Multiphase System%多项体系气体吸收的三维非均相传质模型

    Institute of Scientific and Technical Information of China (English)

    蔡旺锋; 张丹; 许春建; 周明

    2005-01-01

    A three-dimensional heterogeneous mass transfer model was proposed to investigate the enhancement of dispersed particles on gas absorption. The strategy to calculate local and overall enhancement factors is proposed.Instead of a global grid, the composite overlapping grid is adopted, which simplifies the setup and solution of the three-dimensional model equations. It is found that dispersed particle hold-up, particle size, liquid-solid partition coefficient of transported component, characteristic contact time, and the shortest distance between particles and gas-liquid interface have major influence on absorption enhancement factor. The particle-particle interaction on gas absorption and the lateral diffusion of transported component in liquid film were studied with the multi-particle simulation. The proposed model predicted the experimental data from the literature reasonably well.

  5. Prediction and rational correlation of thermophoretically reduced particle mass transfer to hot surfaces across laminar or turbulent forced-convection gas boundary layers

    Science.gov (United States)

    Gokoglu, Suleyman A.; Rosner, Daniel E.

    1986-01-01

    A formulation previously developed to predict and correlate the thermophoretically-augmented submicron particle mass transfer rate to cold surfaces is found to account for the thermophoretically reduced particle mass transfer rate to overheated surfaces such that thermophoresis brings about a 10-decade reduction below the convective mass transfer rate expected by pure Brownian diffusion and convection alone. Thermophoretic blowing is shown to produce effects on particle concentration boundary-layer (BL) structure and wall mass transfer rates similar to those produced by real blowing through a porous wall. The applicability of the correlations to developing BL-situations is demonstrated by a numerical example relevant to wet-steam technology.

  6. Simple setup for gas-phase H/D exchange mass spectrometry coupled to electron transfer dissociation and ion mobility for analysis of polypeptide structure on a liquid chromatographic time scale.

    Science.gov (United States)

    Mistarz, Ulrik H; Brown, Jeffery M; Haselmann, Kim F; Rand, Kasper D

    2014-12-01

    Gas-phase hydrogen/deuterium exchange (HDX) is a fast and sensitive, yet unharnessed analytical approach for providing information on the structural properties of biomolecules, in a complementary manner to mass analysis. Here, we describe a simple setup for ND3-mediated millisecond gas-phase HDX inside a mass spectrometer immediately after ESI (gas-phase HDX-MS) and show utility for studying the primary and higher-order structure of peptides and proteins. HDX was achieved by passing N2-gas through a container filled with aqueous deuterated ammonia reagent (ND3/D2O) and admitting the saturated gas immediately upstream or downstream of the primary skimmer cone. The approach was implemented on three commercially available mass spectrometers and required no or minor fully reversible reconfiguration of gas-inlets of the ion source. Results from gas-phase HDX-MS of peptides using the aqueous ND3/D2O as HDX reagent indicate that labeling is facilitated exclusively through gaseous ND3, yielding similar results to the infusion of purified ND3-gas, while circumventing the complications associated with the use of hazardous purified gases. Comparison of the solution-phase- and gas-phase deuterium uptake of Leu-Enkephalin and Glu-Fibrinopeptide B, confirmed that this gas-phase HDX-MS approach allows for labeling of sites (heteroatom-bound non-amide hydrogens located on side-chains, N-terminus and C-terminus) not accessed by classical solution-phase HDX-MS. The simple setup is compatible with liquid chromatography and a chip-based automated nanoESI interface, allowing for online gas-phase HDX-MS analysis of peptides and proteins separated on a liquid chromatographic time scale at increased throughput. Furthermore, online gas-phase HDX-MS could be performed in tandem with ion mobility separation or electron transfer dissociation, thus enabling multiple orthogonal analyses of the structural properties of peptides and proteins in a single automated LC-MS workflow.

  7. Hydrodynamique, transfert de chaleur et combustion de gaz naturel en lit fluidisé circulant Hydrodynamics, Heat Transfer and Combustion of Natural Gas in a Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Feugier A.

    2006-11-01

    Full Text Available L'hydrodynamique, les transferts de chaleur et la combustion du gaz naturel ont été étudiés dans un réacteur à lit circulant de 15 cm de diamètre et de 7 m de haut. Ce réacteur peut opérer avec des vitesses de gaz allant jusqu'à 15 m/s, jusqu'à des températures de 880-900°C et avec des débits de solides compris entre 0 et 15t/h. Les charges utilisées sont des sables de granulométrie allant de 95 à 625 microns. Le profil de concentration en solides dans le réacteur est déterminé à partir du profil de pression. Une corrélation reliant la vitesse de glissement des particules aux principaux paramètres opératoires, rend compte de façon très satisfaisante de l'ensemble des résultats expérimentaux. La mise en place d'un échangeur en paroi dans la partie supérieure du réacteur a permis la détermination de coefficients d'échange thermique. Ces derniers sont essentiellement fonction de la, concentration en particules au droit de l'échangeur et de la granulométrie des particules. Des valeurs allant jusqu'à 200 W/m2 K peuvent, être obtenues. Enfin, la combustion du méthane s'avère très sensible à la présence de particules dans le réacteur. Ces particules ont un effet inhibiteur. Hydrodynamics, heat transfer and combustion of natural gas have been investigated in a circulating-bed reactor 15 cm in diameter and 7 m high. This reactor can operate with gas velocities up to 15 m/s, at temperature up to 880-900°C and with solids flow rates of between 0 and 15 t/h. The solids used are sands with a particle size ranging from 95 to 625 microns. The solids concentration profile in the reactor is determined from the pressure profile. A correlation linking the slippage velocity of particles to the principal operating parameters very satisfactorily takes into consideration the overall experimental results. The installation of a wall heat exchanger in the upper part of the reactor enabled the heat exchange coefficients to be

  8. Mass Transfer Cooling Near The Stagnation Point

    Science.gov (United States)

    Roberts, Leonard

    1959-01-01

    A simplified analysis is made of mass transfer cooling, that is, injection of a foreign gas, near the stagnation point for two-dimensional and axisymmetric bodies. The reduction in heat transfer is given in terms of the properties of the coolant gas and it is shown that the heat transfer may be reduced considerably by the introduction of a gas having appropriate thermal and diffusive properties. The mechanism by which heat transfer is reduced is discussed.

  9. Flow prediction and heat transfer in a cooling square duch of a gas turbine blade using CFD; Predicciones de flujo y transferencia de calor en un conductor de alabe enfriado de turbina de gas utilizando CFD

    Energy Technology Data Exchange (ETDEWEB)

    Urquiza B, Gustavo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Sierra E, Fernando [Universidad Nacional Autonoma de Mexico, Mexico D.F. (Mexico); Kubiak S, Janusz; Campos A, Rafael [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2003-10-15

    A numerical investigation has been conducted to study the turbulent flow and the heat transfer in a blade turbine coolant passage involving a 180 degrees turn. The study provides a comparison test for two turbulence models. The numerical solution was conducted employing two models for turbulence, the renormalization Group Theory (RNG) and the Reynolds Stress Model (RSM), using a refined grid to model with detail the recirculating flow. Computations are performed with a commercial finite volume code which solves three dimensional, incompressible, Navier-Stokes and Energy equations. At the passage turn, significant secondary flows are present, formed by a pair of symmetrical vortices. Results have been compared against published experimental data for Re = 53 000. Very good agreement is achieved for the prediction of the local static pressure distribution along the passage. A strong effect of rotation has been observed mainly in the flow field as described in detail in the paper. [Spanish] En este trabajo se presenta una investigacion numerica para estudiar el flujo turbulento y la transferencia de calor en un conducto de enfriamiento de un alabes de turbina de gas con giro de 180 grados. El estudio proporciona una comparacion de resultados para dos modelos de turbulencia. La solucion numerica emplea dos modelos de turbulencia: el modelo de esfuerzos de Reynolds (RSM) y el modelo de la teoria del grupo de renormalizacion (RNG), utilizando una malla refinada para modelar con detalle el flujo de recirculacion. Los calculos fueron realizados con un codigo comercial de volumenes finitos el cual resuelve las ecuaciones tridimensionales de Navier-Stoke y de energia para flujo incompresible. En la seccion de giro del conductor, aparecen flujos secundarios significativos, formados por un par de celulas simetricas. Los resultados han sido comparados contra datos experimentales de la literatura para Re = 53 000. se obtuvo un buen acuerdo para la prediccion de la distribucion de

  10. 超重力旋转床中气液传质性能的研究进展%Progress on Performance of Gas-Liquid Mass Transference in Hypergravity Rotating Packet Bed

    Institute of Scientific and Technical Information of China (English)

    方健; 詹丽; 余国贤; 路平; 晋梅

    2015-01-01

    Rotating packed bed is a kind of new reaction device in industrial chemistry process ,used the centrifugal force generated by materials filling in high speed rotating to imitate the hypergravity enviro⁃ment ,the liquid contacted reversely with the gas phase at high relative velocity in curving hole of packing bed under the conditions of high dispersion ,high turbulence ,strong mixture and quick renew of inter⁃face ,it strongly intensified the gas-liquid mass transference. Reviewed the influence factors on the effect of gas-liquid mass transference in hypergravity rotating packed bed ,introduced the typical theory on gas-liquid mass transference ,moreover , introduced recent progress of the theory and the model of gas-liquid transference in hypergravity rotating packed bed ,prospected the intensifying technology in this field.%超重力旋转床是一种强化化学工业过程的新型反应器,利用高速旋转填料所产生的离心力来模拟超重力环境,液体在高分散、高湍动、强混合以及界面的快速更新下与气相以极大的相对速度在填料的弯曲孔道中进行逆向接触,极大地强化了气液传质过程而不液泛。对影响超重力旋转床气液传质效果的因素,如填料、转子转速以及气/液体流量等进行了综述,并在此基础上,介绍了典型的气液传质理论和近年来国内外对超重力旋转床中气液传质理论及气液传质模型的研究进展,最后对超重力旋转床气液传质的强化技术进行了展望。

  11. Mass Transfer with Chemical Reaction.

    Science.gov (United States)

    DeCoursey, W. J.

    1987-01-01

    Describes the organization of a graduate course dealing with mass transfer, particularly as it relates to chemical reactions. Discusses the course outline, including mathematics models of mass transfer, enhancement of mass transfer rates by homogeneous chemical reaction, and gas-liquid systems with chemical reaction. (TW)

  12. Toward a Full Simulation of the Basic Oxygen Furnace: Deformation of the Bath Free Surface and Coupled Transfer Processes Associated with the Post-Combustion in the Gas Region

    Science.gov (United States)

    Doh, Y.; Chapelle, P.; Jardy, A.; Djambazov, G.; Pericleous, K.; Ghazal, G.; Gardin, P.

    2013-06-01

    The present article treats different phenomena taking place in a steelmaking converter through the development of two separate models. The first model describes the cavity produced at the free surface of the metal bath by the high-speed impinging oxygen jet. The model is based on a zonal approach, where gas compressibility effects are taken into account only in the high velocity jet region, while elsewhere the gas is treated as incompressible. The volume of fluid (VOF) method is employed to follow the deformation of the bath free surface. Calculations are presented for two- and three-phase systems and compared against experimental data obtained in a cold model experiment presented in the literature. The influence on the size and shape of the cavity of various parameters and models (including the jet inlet boundary conditions, the VOF advection scheme, and the turbulence model) is studied. Next, the model is used to simulate the interaction of a supersonic oxygen jet with the surface of a liquid steel bath in a pilot-scale converter. The second model concentrates on fluid flow, heat transfer, and the post-combustion reaction in the gas phase above the metal bath. The model uses the simple chemical reaction scheme approach to describe the transport of the chemical species and takes into account the consumption of oxygen by the bath and thermal radiative transfer. The model predictions are in reasonable agreement with measurements collected in a laboratory experiment and in a pilot-scale furnace.

  13. Gas phase ion chemistry

    CERN Document Server

    Bowers, Michael T

    1979-01-01

    Gas Phase Ion Chemistry, Volume 2 covers the advances in gas phase ion chemistry. The book discusses the stabilities of positive ions from equilibrium gas-phase basicity measurements; the experimental methods used to determine molecular electron affinities, specifically photoelectron spectroscopy, photodetachment spectroscopy, charge transfer, and collisional ionization; and the gas-phase acidity scale. The text also describes the basis of the technique of chemical ionization mass spectrometry; the energetics and mechanisms of unimolecular reactions of positive ions; and the photodissociation

  14. Adjoint Sensitivity Analysis of Radiative Transfer Equation: Temperature and Gas Mixing Ratio Weighting Functions for Remote Sensing of Scattering Atmospheres in Thermal IR

    Science.gov (United States)

    Ustinov, E.

    1999-01-01

    Sensitivity analysis based on using of the adjoint equation of radiative transfer is applied to the case of atmospheric remote sensing in the thermal spectral region with non-negligeable atmospheric scattering.

  15. Investigation on heat transfer evaluation for a more efficient two-zone combustion model in the case of natural gas SI engines

    OpenAIRE

    Lounici, Mohand Said; Loubar, Khaled; Balistrou, Mourad; Tazerout, Mohand

    2010-01-01

    Abstract Two-zone model is one of the most interesting engine simulation tools, especially for SI engines. However, the pertinence of the simulation depends on the accuracy of the heat transfer model. In fact, an important part of the fuel energy is transformed to heat loss from the chamber walls. Also, knock appearance is closely related to heat exchange. However, in the previous studies using two-zone models, many choices are made for heat transfer evaluation and no choice influe...

  16. Gas Stirring to Enhance Mass Transfer During Extraction of Copper by Naphthenic Acid%用气相搅动方法强化环烷酸萃取铜的质量传递

    Institute of Scientific and Technical Information of China (English)

    Olfat A Fadali

    2004-01-01

    The effect of nitrogen sparging on the mass transfer rate in the extraction of copper from aqueous solution by a kerosene solution of naphthenic acids was studied.Investigated variables: nitrogen flow rate, copper ion concentration, and extraction temperature. It was concluded that the mass transfer coefficient of copper extraction was related to the gas flow rate by the equation: K = aU. The effect of temperature on the mass transfer coefficient was found to obey Arrhenius equation with an activation energy of 2875 calories. The mass transfer coefficient was found to decrease with increasing copper ion concentration.%研究了氮注射对环烷酸萃取溶液中铜离子的质量转移速率的影响.研究的因素包括:氮流速、铜离子浓度及萃取温度.结果发现,铜离子萃取的质量转移速率与气体流速有关,并遵守如下方程:K=aU,温度对质量转移速率的影响遵循阿列纽斯方程,其活化能为2875卡路里;质量转移系数随溶液中铜离子浓度的增加而降低.

  17. Experimental Study and Numerical Simulation on Shell Side Heat Transfer of Novel Gas-to-Gas Heat Exchanger with Corrugated Flat Tubes%新型波纹扁管气-气换热器壳程传热实验研究与数值模拟

    Institute of Scientific and Technical Information of China (English)

    曾国浩; 凌子夜; 高学农; 张正国; 曾文良

    2015-01-01

    Aimed at the characteristics of gas-to-gas heat transfer, a novel heat exchanger with the corrugated flat tubes is developed. An experimental system for researching heat transfer process between hot air with cold air is set up. In the experimental heat exchanger, the hot air flows in tube side and the cold air flows in the shell side. The Fluent 6.3 software was used to simulate heat transfer coefficient and pressure drop in the shell side. Results show that while the hot air velocity is 20 ms1 in the tube side, the cold air velocity within 15 to 25 ms1 in the shell side, the total heat transfer coefficient of heat exchanger is 81~88 Wm2K1. The numerical simulation heat transfer coefficients and the simulated pressure drops are in good agreement with correspondent experimental data. Corrugated flat tube heat exchanger has the advantages of high efficiency and compact, it is suitable for application in gas-to-gas heat transfer field.%针对气-气换热的特点,开发出了一种新型的波纹扁管换热器。构建了热空气与冷空气换热的实验系统,热空气在管程流动,冷空气在壳程流动,实验研究了波纹扁管气-气换热器的传热性能,并采用Fluent 6.3软件对壳程空气的传热与压降进行了数值模拟。结果表明,当管程空气流速为20 ms1,壳程空气流速在15~25 ms1,换热器的总传热系数为81~88 Wm2K1。壳程传热系数和壳程压降的数值模拟结果与实验值吻合良好。波纹扁管换热器具有高效紧凑的优点,适用于气-气换热领域。

  18. Efeito do gás de proteção e do modo de transferência na aplicação da liga 625 em aço carbono Effect of shielding gas and transfer mode on the application of 625 alloy in carbon steel

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Iconomos Baixo

    2009-12-01

    Full Text Available Neste trabalho foram analisados os efeitos do gás de proteção (Ar, Ar/CO2, Ar/O2 e Ar/He/O2 e do modo de transferência (curto-circuito e corrente pulsada utilizando o processo MIG/ MAG com arame ER-NiCrMo-3 para produzir depósitos sobre chapa assim como o passe de raiz em juntas em V produzidas em aço ABNT 1020. Os resultados mais favoráveis na soldagem do passe de raiz foram obtidos na soldagem com corrente pulsada, empregando uma junta em V com abertura de 90º e atmosfera de Ar + 25% CO2. A utilização de atmosferas de proteção com 20% Hélio e baixo percentual de gás ativo não produziu os resultados esperados, sendo eficaz somente na soldagem com deposição sobre chapa, porém tímida em produzir resultados satisfatórios na solda do passe de raiz. Resultados ruins foram obtidos na soldagem com transferência por curto-circuito, independente do gás de proteção, e quando utilizada atmosfera composta por Argônio puro, independente do modo de transferência ajustado.In this study the effect of shielding gas (Ar, Ar/CO2, Ar/O2 and Ar/He/O2 and transfer mode (short-circuit and pulsed current in MIG/MAG welding with ER-NiCrMo-3 wire to produce bead-on-plate deposits and root passes in "V" joints of ABNT 1020 steel were analyzed. The most favorable results in root pass welding were obtained with pulsed current, employing a "V" joint with a 90º aperture and Ar+25%CO2 atmosphere. The use of shielding atmospheres with 20% helium and a low percentage of active gas did not produce the expected results, being effective only in bead-on-plate weld deposition. However, it was not very effective to produce satisfactory results in root pass welding. Poor results were obtained in the welding with short-circuit transfer regardless of the used shielding gas, and when an atmosphere of pure argon was used, regardless of the mode of transfer.

  19. Report of study group 10.3 ''gas market development in developing countries: technology transfer and financing''; Rapport du groupe d'etudes 10.3 ''l'evolution du marche gazier dans les pays en voie de developpement. Transfert des tehnologies et financement''

    Energy Technology Data Exchange (ETDEWEB)

    Okimi, H.

    2000-07-01

    The study of SG10.3 in this triennium focuses on the gas downstream in developing countries. Discussions on gas developments have flourished in the international gas community often with more emphasis on production and transmission. This may be because that gas distribution is an every day activity for gas enterprises in many member countries and is thought not new. When we look at developments in developing countries, however, the gas downstream development is more important than we normally think. Upstream gas cannot be developed without confidence in gas market; then this affects the whole gas development which may not be achieved without a guaranteed market. A gas market is not simply there but has to be developed. When a gas field is found, people may simply think that there is a market for the gas somewhere. But gas is not a commodity in the countries where there is no distribution networks. Market development is an infrastructure development there, and it often requires complicated processes including financing, technology transfer, implementation of gas networks, marketing, and operation and maintenance. (author)

  20. Natural Gas Market Hubs

    Data.gov (United States)

    Department of Homeland Security — A hub is a physical transfer point for natural gas where several pipelines are connected. A market center is a hub where the operator offers services that facilitate...

  1. 固体颗粒对搅拌罐中气液传质的影响%Influence of Solid Particles on Gas-liquid Mass Transfer in a Stirred Tank

    Institute of Scientific and Technical Information of China (English)

    沙作良; 韩冰; Louhi-Kultanen Marjatta

    2015-01-01

    在带有Rushton搅拌桨的搅拌罐中,研究了恒定温度和恒定气体流量条件下不同粒径的固体颗粒和搅拌速率对气液传质速率的影响.结果表明:固体体积分数小于0.08%,时,石英砂(41.1,µm和640,µm)对气液体积传质系数kLa没有影响;而对于碳酸钙颗粒(5.07,µm),当其体积分数大于0.4%,时,kLa 随着固体含量的增加而增大.通过对实验数据的拟合,得到一个含有功率输入、浆液有效黏度、颗粒粒径和固含量的半经验公式,该公式能够很好地表达颗粒对气液传质的影响.%Gas-liquid mass transfer in a stirred tank was studied with a Rushton impeller. Mass transfer rate was investigated using various concentration of different-sized solid particles,as well as different rotation speed at a constant temperature and gas flow rate. When the solid volume fraction was less than 0.08%,no effect of quartz sands(41.1,µm and 640,µm)on the volumetric mass transfer kLa was observed. However,kLa was increased when the solid volume fraction of calcium carbonate particles(5.07,µm)was above 0.4%,. A semi-empirical equation of specific power input,effective viscosity of slurry,particle size,and solid loading was obtained by fitting the experimental data. This equation can successfully describe the effect of particles on gas-liquid mass transfer.

  2. Investigation on natural gas heater with different heat-transfer medium%不同中间载热介质天然气加热炉的研究

    Institute of Scientific and Technical Information of China (English)

    郭韵; 曹伟武; 钱尚源; 严平

    2012-01-01

    As a special type of furnace,the natural gas heater adopts the indirect heating by the heat-transfer medium.Apparently,the properties of the heat-transfer medium and the form of heat transfer process of the heat-transfer medium in the cylinder are the key elements that greatly affect the thermal efficiency of natural gas heater.Analysis and comparison of the temperature distribution and flow condition between the water and ethylene glycol in the cylinder were carried out by experimental investigations.Based on the investigations on medium selection and heater’s integral structure and combining with the engineering practical needs,effective measures to improve the efficiency of natural gas heaters have been brought forward in this article and the technology has got itself the China invention patents.%天然气加热炉是采用中间载热介质间接加热的一种特殊的炉型形式,中间载热介质的性质及其传热过程的形成是影响天然气加热炉效率的重要关键因素。本文通过天然气加热炉试验系统对大筒体内水和乙二醇两种不同中间载热介质的温度分布和热流场进行了分析比较,研究不同中间载热介质对天然气加热炉换热的影响,并结合工程实际的需要,从中间载热介质的选择和加热炉整体传热结构两方面,提出了改善天然气加热炉效率的有效途径,并获得了国家发明专利授权。

  3. 75 FR 39680 - Houston Pipe Line Company LP, Worsham-Steed Gas Storage, L.P., Energy Transfer Fuel, LP, Mid...

    Science.gov (United States)

    2010-07-12

    ... Storage, L.P., Energy Transfer Fuel, LP, Mid Continent Market Center, L.L.C., Oasis Pipeline, LP (Not... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. PR10-44-000; Docket No. PR10-46-000; Docket No....

  4. Laboratory Determination of Gas-Side Mass Transfer Coefficients Applicable to Soil Venting Systems for Removing Petroleum Hydrocarbons from Vadose Zone Soils

    Science.gov (United States)

    1991-01-01

    monolayers situated on either side of this interface (Treybal, 1980; Henley and Seader , 1981). This equilibrium condition may be used to describe mass transfer...W.F. Reehl and D.H. Rosenblatt, eds., Handbook of Chemical Property Estimation Methods, American Chemical Society, 1990. Henley, E.J. and J.D. Seader

  5. Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

    Science.gov (United States)

    Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

    2011-01-01

    Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

  6. CFD-based investigation of heat transfer characteristics of flue gas-water eat exchanger panels produced with a novel manufacturing proces

    NARCIS (Netherlands)

    Fukue, T.; Spitas, C.; Dwaikat, M.; Ishizuka, M.

    2013-01-01

    This study describes the characteristics of a panel geometry obtained by a novel manufacturing process for the development of ultra-compact flue gas-water condensing heat exchangers. In this process two stainless steel sheets are prepared and stacked and then brazed together in a special pattern out

  7. Discussion on waste heat comprehensive utilization of heat transfer oil and waste gas%导热油-烟气综合余热利用工艺探讨

    Institute of Scientific and Technical Information of China (English)

    姜学仕; 倪军亮; 范孟洲; 郭黎明

    2015-01-01

    梁式竖窑导热油余热由于热量小、温度低而易被忽视。通过对梁式竖窑热工分析及导热油余热分析,提出了导热油-烟气综合余热利用方案,并对经济效益进行分析。指出导热油烟气综合利用投资省,回报率高,操作简单,节能减排。%With low calories and low temperature,the waste heat of the heat transfer oil in beam shaft kiln was easy to overlook. Based on thermal analysis and waste heat analysis of the heat transfer oil, the article proposed a comprehensive utilization program of the waste heat of heat transfer oil and waste gas,which had the features such as low invest,high return,simple operation,energy saving and emission reduction.

  8. Heat transfer in cryogenic helium gas by turbulent Rayleigh-Bénard convection in a cylindrical cell of aspect ratio 1

    Science.gov (United States)

    Urban, Pavel; Hanzelka, Pavel; Musilová, Věra; Králík, Tomáš; La Mantia, Marco; Srnka, Aleš; Skrbek, Ladislav

    2014-05-01

    We present experimental results on the heat transfer efficiency of cryogenic turbulent Rayleigh-Bénard convection (RBC) in a cylindrical cell 0.3 m in both diameter and height which has improvements with respect to various corrections connected with finite thermal conductivity of sidewalls and plates. The heat transfer efficiency described by the Nusselt number {\\rm{Nu}}={\\rm{Nu}}({\\rm{Ra}},Pr ) is investigated for the range of Rayleigh number {{10}^{6}}account. In contrast, if the mean temperature is determined as an arithmetic mean of the bottom and top plate temperatures, {\\rm{Nu}}({\\rm{Ra}})\\propto {\\rm{R}}{{{\\rm{a}}}^{\\gamma }} displays spurious crossover to higher γ that might be misinterpreted as a transition to the ultimate Kraichnan regime. The second step of our analysis, reported here for the first time, is to ignore the NOB effects affecting the top half of the RBC cell. We replace it by the inverted nearly OB bottom half in order to eliminate the boundary layer asymmetry. This leads to the effective temperature difference \\Delta {{T}_{{\\rm{eff}}}}=2({{T}_{{\\rm{b}}}}-{{T}_{{\\rm{c}}}}), where {{T}_{{\\rm{b}}}} denotes the bottom plate temperature, and to effective {\\rm{N}}{{{\\rm{u}}}_{{\\rm{eff}}}} and {\\rm{R}}{{{\\rm{a}}}_{{\\rm{eff}}}} values. The effective heat transfer efficiency obtained, showing no tendency of crossover to the ultimate regime up to 2\\times {{10}^{15}} in {\\rm{R}}{{{\\rm{a}}}_{{\\rm{eff}}}}, is reported and discussed.

  9. Vapor-phase combustion and heat and mass transfer during the interaction of a high-temperature gas flow with a solid

    Energy Technology Data Exchange (ETDEWEB)

    Pushkin, V.N.; Sukhov, G.S.; Iarin, L.P.

    1988-08-01

    The problem of the combustion of a solid in incoming gas flow containing an oxidizer is solved by using an analytical model allowing for phase transitions and chemical transformations and assuming a quasi-equilibrium state on the free surface and diffusion combustion at the flame front. The hydrodynamic, temperature, and concentration fields are investigated for the case of flow past a body with a spherical nose. The principal combustion characteristics are determined as a function of the incoming flow intensity. 6 references.

  10. Coupled heat transfer analysis of air cooling gas turbine%气冷涡轮气热耦合数值模拟

    Institute of Scientific and Technical Information of China (English)

    周驰; 王强; 郭兆元; 黄家骅; 冯国泰

    2009-01-01

    应用有限差分方法进行气冷涡轮气热耦合计算,研究了影响气热耦合计算精度的几个因素,包括:流场壁面附近的计算网格、湍流转捩模型以及能量方程中普朗特数的计算等.为了能够应用高精度离散格式,并加快计算速度,采用了气热耦合动力学的微分方程与相应的差分格式,采用了结构化网格.数值计算结果与试验进行对比表明,在流场壁面附近应采用正交性好的网格,并在计算中考虑转捩的影响;而普朗特数的变化对本次计算的影响不大.%Coupled heat transfer simulations with a FDM coupled solver were carried out to study the factors effecting the coupled simulation accuracy.Such factors included numerical grids around the blade wall,the turbulence and transition models,and the variation of Pradtl number.The difference scheme corresponding to the conjugate heat transfer dynamics differential equation and structured grids were employed to ensure the computational accuracy and speed.The comparison between numerical results and the measured ones shows that the grids quality around the blade wall and the transition model are essential for the coupled heat transfer simulations,and that the variation of Prandtl number affects slightly on the numerical results.

  11. Hypervalent radical formation probed by electron transfer dissociation of zwitterionic tryptophan and tryptophan-containing dipeptides complexed with Ca2+ and 18-crown-6 in the gas phase.

    Science.gov (United States)

    Fujihara, Akimasa; Matsuo, Sou; Tajiri, Michiko; Wada, Yoshinao; Hayakawa, Shigeo

    2015-10-01

    The relationship between peptide structure and electron transfer dissociation (ETD) is important for structural analysis by mass spectrometry. In the present study, the formation, structure and reactivity of the reaction intermediate in the ETD process were examined using a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. ETD product ions of zwitterionic tryptophan (Trp) and Trp-containing dipeptides (Trp-Gly and Gly-Trp) were detected without reionization using non-covalent analyte complexes with Ca(2+) and 18-crown-6 (18C6). In the collision-induced dissociation, NH3 loss was the main dissociation pathway, and loss related to the dissociation of the carboxyl group was not observed. This indicated that Trp and its dipeptides on Ca(2+) (18C6) adopted a zwitterionic structure with an NH3 (+) group and bonded to Ca(2+) (18C6) through the COO(-) group. Hydrogen atom loss observed in the ETD spectra indicated that intermolecular electron transfer from a molecular anion to the NH3 (+) group formed a hypervalent ammonium radical, R-NH3 , as a reaction intermediate, which was unstable and dissociated rapidly through N-H bond cleavage. In addition, N-Cα bond cleavage forming the z1 ion was observed in the ETD spectra of Trp-GlyCa(2+) (18C6) and Gly-TrpCa(2+) (18C6). This dissociation was induced by transfer of a hydrogen atom in the cluster formed via an N-H bond cleavage of the hypervalent ammonium radical and was in competition with the hydrogen atom loss. The results showed that a hypervalent radical intermediate, forming a delocalized hydrogen atom, contributes to the backbone cleavages of peptides in ETD.

  12. The Unique Gas-Phase Chemistry of the [AuO](+) /CH4 Couple: Selective Oxygen-Atom Transfer to, Rather than Hydrogen-Atom Abstraction from, Methane.

    Science.gov (United States)

    Zhou, Shaodong; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2016-08-26

    The thermal reaction of [AuO](+) with methane has been explored using FT-ICR mass spectrometry complemented by high-level quantum chemical calculations. In contrast to the previously studied congener [CuO](+) , and to [AgO](+) , [AuO](+) reacts with CH4 exclusively via oxygen-atom transfer to form CH3 OH, and a novel mechanistic scenario for this selective oxidation process has been revealed. Also, the origin of the inertness of the [AgO](+) /CH4 couple has been addressed computationally.

  13. Mechanistic aspects of gas-phase hydrogen-atom transfer from methane to [CO](·+) and [SiO](·+) : why do they differ?

    Science.gov (United States)

    Dietl, Nicolas; Troiani, Anna; Schlangen, Maria; Ursini, Ornella; Angelini, Giancarlo; Apeloig, Yitzhak; de Petris, Giulia; Schwarz, Helmut

    2013-05-17

    The reactivity of the two diatomic congeneric systems [CO](·+) and [SiO](·+) towards methane has been investigated by means of mass spectrometry and quantum-chemical calculations. While [CO](·+) gives rise to three different reaction channels, [SiO](·+) reacts only by hydrogen-atom transfer (HAT) from methane under thermal conditions. A theoretical analysis of the respective HAT processes reveals two distinctly different mechanistic pathways for [CO](·+) and [SiO](·+), and a comparison to the higher metal oxides of Group 14 emphasizes the particular role of carbon as a second-row p element.

  14. An Unsteady Heterogeneous Mass Transfer Model for Gas Absorption Enhanced by Dispersed Third Phase Droplets%第三分散相液滴增强气体吸收的一维非稳态非均相传质模型

    Institute of Scientific and Technical Information of China (English)

    沈树华; 马友光; 卢素敏; 朱春英

    2009-01-01

    A model for one-dimensional unsteady heterogeneous mass transfer was developed based on Danck-werts' surface renewal theory in order to describe the mass transfer enhancement of absorption process for a slightly soluble gas in a gas-liquid-liquid system. The model accounts for the mass transfer resistance within the dispersed phase and the effect of emulsion viscosity on mass transfer. An analytical solution for enhancement factor was ob-tained by Laplace domain transformation. The absorption rates of carbon dioxide in the dodecane-in-water and cas-tor oil-in-water systems were measured in a thermostatic reactor, and the enhancement factors were calculated at different volume fractions of dispersed phase and stirrer speeds. The model predictions agree well with the experi-mental data.

  15. Numerical modeling of two-dimensional heat-transfer and temperature-based calibration using simulated annealing optimization method: Application to gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Bjelić Mišo B.

    2016-01-01

    Full Text Available Simulation models of welding processes allow us to predict influence of welding parameters on the temperature field during welding and by means of temperature field and the influence to the weld geometry and microstructure. This article presents a numerical, finite-difference based model of heat transfer during welding of thin sheets. Unfortunately, accuracy of the model depends on many parameters, which cannot be accurately prescribed. In order to solve this problem, we have used simulated annealing optimization method in combination with presented numerical model. This way, we were able to determine uncertain values of heat source parameters, arc efficiency, emissivity and enhanced conductivity. The calibration procedure was made using thermocouple measurements of temperatures during welding for P355GH steel. The obtained results were used as input for simulation run. The results of simulation showed that represented calibration procedure could significantly improve reliability of heat transfer model. [National CEEPUS Office of Czech Republic (project CIII-HR-0108-07-1314 and to the Ministry of Education and Science of the Republic of Serbia (project TR37020

  16. Natural gas; Gas Natural

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Carlos A.; Moraes, Claudia C.D. [Eletricidade de Sao Paulo S.A. (ELETROPAULO), Sao Paulo, SP (Brazil); Fonseca, Carlos H.F. [Centrais Eletricas de Santa Catarina S.A., Florianopolis, SC (Brazil); Silva, Clecio Fabricio da; Alves, Ricardo P. [Companhia Paranaense de Energia (COPEL), Curitiba, PR (Brazil); Sposito, Edivaldo Soares; Hulle, Lutero [Espirito Santo Centrais Eletricas S.A. (ESCELSA), Vitoria, ES (Brazil); S. Martins, Icaro da [Centrais Eletricas do Norte do Brasil S.A. (ELETRONORTE), Belem, PA (Brazil); Vilhena, Joao Luiz S. de [Companhia Energetica de Minas Gerais (CEMIG), Belo Horizonte, MG (Brazil); Fagundes, Zaluar Aquino [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul, Porto Alegre, RS (Brazil)

    1996-12-31

    An increase in the consumption of natural gas in Brazil is an expected fact in what concerns energetic planning. This work presents the existing situation in what concerns natural gas utilization in the main world economies, as well as an analysis of the participation of this fuel among the energy final consumption per sources. The Brazilian consumption of natural gas is also analysed as well as the international agreement between Brazil and Bolivia for natural gas commercialization. Some legal, institutional and political aspects related to natural gas commercialization are also discussed. Finally, several benefits to be brought by the utilization of natural gas are presented 10 refs., 3 tabs.

  17. Theoretical investigation of 2-(iminomethyl)phenol in the gas phase as a prototype of ultrafast excited-state intramolecular proton transfer

    Science.gov (United States)

    Daengngern, Rathawat; Prommin, Chanatkran; Rungrotmongkol, Thanyada; Promarak, Vinich; Wolschann, Peter; Kungwan, Nawee

    2016-07-01

    Photophysical properties of the smallest o-hydroxy Schiff base, 2-(iminomethyl)phenol (IMP), were elucidated using B3LYP and RI-ADC(2) methods. Cis-enol is the most stable conformation in ground state. Potential energy profiles show that enol-keto tautomerization occurs with a small barrier. However, isomerization from cis- to trans-keto is not possible because of a high barrier. The trans-keto tautomer is only accessible through a conical intersection (CI) after excited-state intramolecular proton transfer (ESIPT). Dynamics results show that cis-enol undergoes ultrafast ESIPT to give cis-keto. Regions of CI may be initiated to yield keto forms through radiativeless process with torsion twist of about 40-50°.

  18. Energy transfer dynamics and kinetics of elementary processes (promoted) by gas-phase CO2 -N2 collisions: Selectivity control by the anisotropy of the interaction.

    Science.gov (United States)

    Lombardi, Andrea; Pirani, Fernando; Laganà, Antonio; Bartolomei, Massimiliano

    2016-06-15

    In this work, we exploit a new formulation of the potential energy and of the related computational procedures, which embodies the coupling between the intra and intermolecular components, to characterize possible propensities of the collision dynamics in energy transfer processes of interest for simulation and control of phenomena occurring in a variety of equilibrium and nonequilibrium environments. The investigation reported in the paper focuses on the prototype CO2 -N2 system, whose intramolecular component of the interaction is modeled in terms of a many body expansion while the intermolecular component is modeled in terms of a recently developed bonds-as-interacting-molecular-centers' approach. The main advantage of this formulation of the potential energy surface is that of being (a) truly full dimensional (i.e., all the variations of the coordinates associated with the molecular vibrations and rotations on the geometrical and electronic structure of the monomers, are explicitly taken into account without freezing any bonds or angles), (b) more flexible than other usual formulations of the interaction and (c) well suited for fitting procedures better adhering to accurate ab initio data and sensitive to experimental arrangement dependent information. Specific attention has been given to the fact that a variation of vibrational and rotational energy has a higher (both qualitative and quantitative) impact on the energy transfer when a more accurate formulation of the intermolecular interaction (with respect to that obtained when using rigid monomers) is adopted. This makes the potential energy surface better suited for the kinetic modeling of gaseous mixtures in plasma, combustion and atmospheric chemistry computational applications. © 2016 Wiley Periodicals, Inc.

  19. The custody transfer commercial metering and management of uzbekistan-China natural gas pipeline%中乌跨国天然气管道的计量交接与管理

    Institute of Scientific and Technical Information of China (English)

    王仲瑀; 于栋; 郑宏伟

    2012-01-01

    从技术层面和管理层面叙述了我国第一条跨国天然气管道的计量计算方法和计量管理、交接模式。天然气贸易计量数据采用中乌哈三方公认的第三方的AGA报告和ISO标准进行计算,并根据实际情况、参考中国与乌兹别克斯坦的相关标准制定管理制度和规范作为补充,形成了中亚地区跨境贸易计量交接与管理的标准。%The calculation on metrology and model of the commercial metering data of China' s first cross-border natural gas pipeline from technology and management is introduced in the article. The commercial metering data is calculated according to AGA (American Gas Association) related reports which are recognized by China, Uzbekistan and Kazakhstan. The standard for cross-border custody transfer commercial metering and management is fulfilled successfully on the basis of the actual conditions and related standards and regulations in China and Uzbekistan.

  20. Radionuclide transfer. Radionuklid Transfer

    Energy Technology Data Exchange (ETDEWEB)

    Gerber, G.B.

    1993-01-01

    The research project described here had the aim to obtain further information on the transfer of nuclides during pregnancy and lactation. The tests were carried out in mini-pigs and rats receiving unchanging doses of radionuclides with the food. The following findings were revealed for the elements examined: Fe, Se, Cs and Zn were characterized by very high transfer levels in the mother, infant and foetus. A substantial uptake by the mother alone was observed for Co, Ag and Mn. The uptake by the foetus and infant here was 1 to 10 times lower. A preferential concentration in certain tissues was seen for Sr and Tc; the thyroid levels of Tc were about equally high in mothers and infants, while Sr showed less accumulation in the maternal bone. The lanthanide group of substances (Ce, Eu and Gd as well as Y and Ru) were only taken up to a very limited extent. The uptake of the examined radionuclides (Fe, Co, Ag, Ce) with the food ingested was found here to be ten times greater in rats as compared to mini-pigs. This showed that great caution must be observed, if the behaviour of radionuclides in man is extrapolated from relevant data obtained in rodents. (orig./MG)

  1. Controlled Environment Specimen Transfer

    DEFF Research Database (Denmark)

    Damsgaard, Christian Danvad; Zandbergen, Henny W.; Hansen, Thomas Willum

    2014-01-01

    an environmental transmission electron microscope to an in situ X-ray diffractometer through a dedicated transmission electron microscope specimen transfer holder, capable of sealing the specimen in a gaseous environment at elevated temperatures. Two catalyst material systems have been investigated; Cu/ZnO/Al2O3...... transferred in a reactive environment to the environmental transmission electron microscope where further analysis on the local scale were conducted. The Co/Al2O3 catalyst was reduced in the environmental microscope and successfully kept reduced outside the microscope in a reactive environment. The in situ......Specimen transfer under controlled environment conditions, such as temperature, pressure, and gas composition, is necessary to conduct successive complementary in situ characterization of materials sensitive to ambient conditions. The in situ transfer concept is introduced by linking...

  2. Condensation heat transfer of pure steam and steam from gas-steam mixture in tubes of AES-2006 PHRS SG heat exchanger

    Science.gov (United States)

    Balunov, B. F.; Il'in, V. A.; Shcheglov, A. A.; Lychakov, V. D.; Alekseev, S. B.; Kuhtevich, V. O.; Svetlov, S. V.; Sidorov, V. G.

    2017-01-01

    Results of experimental determination of the average heat transfer coefficient upon condensation of pure steam αc and steam from air-steam mixture αas.m in tubes of a large-scale model of the emergency cooling heat exchanger in the system of passive heat removal through steam generators of AES-2006 project at Leningrad II NPP are presented. The model contained 16 parallel tubes with a diameter of 16 × 2 mm and a length of 2.9 m connected to the upper steam distributing and lower condensate gathering horizontal collectors; the distance between their axes was 2.28 m. The tube segments were vertical, horizontal, or inclined. The internal diameter of the collectors was 40 or 60 mm. The model was placed in the lower part of a tank with a height of 6.5 m and a volume of 5.85 m3 filled with boiling water at atmospheric pressure. The experimental parameters were as follows: pressure range 0.43-7.77 MPa, condensate Reynolds number Ref = (0.87-9.3) × 103, and average air volume fraction at the segment with air-steam mixture 0.18-0.85. The studies showed that nonuniformity of static pressure distribution along the steam-distributing collector strongly influences the reduction of αc value (ejecting effect). The agreement between experimental and calculated according to statutory guidelines values of αc for vertical tubes is achieved if the dynamic head of the steam flow at the input of the steam-distributing collector does not exceed 1 kPa. Equations for calculation of the diffusion heat transfer coefficient at steam condensation from the air-steam mixture αas.m on the internal tube surface are proposed. In the considered conditions, air is completely displaced by steam flow from the upper to the lower part of the tubes. The boundary between these regions is characterized by an average reduced steam velocity through this cross section of 1.6 ± 0.4 m/s. Above the boundary cross section, it is recommended to calculate αc. according to [1].

  3. Multicomponent Gas-Particle Flow and Heat/Mass Transfer Induced by a Localized Laser Irradiation on a Urethane-Coated Stainless Steel Substrate

    CERN Document Server

    Afrin, Nazia; Zhang, Yuwen; Chen, J K; Ritter, Robin; Lampson, Alan; Stohs, Jonathan

    2016-01-01

    A three-dimensional numerical simulation is conducted for a complex process in a laser-material system, which involves heat and mass transfer in a compressible gaseous phase and chemical reaction during laser irradiation on a urethane paint coated on a stainless steel substrate. A finite volume method (FVM) with a co-located grid mesh that discretizes the entire computational domain is employed to simulate the heating process. The results show that when the top surface of the paint reaches a threshold temperature of 560 K, the polyurethane starts to decompose through chemical reaction. As a result, combustion products CO2, H2O and NO2 are produced and chromium (III) oxide, which serves as pigment in the paint, is ejected as solid parcels from the paint into the gaseous domain. Variations of temperature, density and velocity at the center of the laser irradiation spot, and the concentrations of reaction reactant/products in the gaseous phase are presented and discussed, by comparing six scenarios with differen...

  4. Solid H2 versus solid noble-gas environment: Influence on photoinduced hydrogen-atom transfer in matrix-isolated 4(3H)-pyrimidinone

    Science.gov (United States)

    Lapinski, Leszek; Nowak, Maciej J.; Rostkowska, Hanna

    2017-03-01

    UV-induced transformations have been studied for 4(3H)-pyrimidinone monomers isolated in low-temperature Ar, Ne, n-D2, and n-H2 matrices. The observed photochemical behavior of the compound drastically depended on the solid matrix environment. For 4(3H)-pyrimidinone isolated in solid Ar, the UV-induced phototautomeric transformation was clearly the dominating process, leading to a nearly quantitative conversion of the oxo reactant into the hydroxy product. For solid Ne environment, the oxo → hydroxy transformation was still the major photoprocess, but yielding less of the hydroxy product (ca. 64% of the yield in solid Ar). For 4(3H)-pyrimidinone isolated in solid n-H2, the oxo → hydroxy phototautomeric conversion did not occur (or occurred at a very tiny scale). Also for deuterated 4(3D)-pyrimidinone isolated in solid hydrogen, the analogous oxo → deuteroxy phototransformation was not observed. Finally, for the compound trapped in solid n-D2, the oxo → hydroxy phototautomerism clearly occurred, but the yield of the hydroxy tautomer was small (ca. 18% of the yield in solid Ar). Apart from hydrogen-atom-transfer processes, two other phototransformations: generation of open-ring conjugated ketene and valence Dewar isomer were observed for the compound isolated in Ar, Ne, n-D2, and n-H2 matrices.

  5. Charge transfer reactions between gas-phase hydrated electrons, molecular oxygen and carbon dioxide at temperatures of 80-300 K.

    Science.gov (United States)

    Akhgarnusch, Amou; Tang, Wai Kit; Zhang, Han; Siu, Chi-Kit; Beyer, Martin K

    2016-09-14

    The recombination reactions of gas-phase hydrated electrons (H2O)n˙(-) with CO2 and O2, as well as the charge exchange reaction of CO2˙(-)(H2O)n with O2, were studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry in the temperature range T = 80-300 K. Comparison of the rate constants with collision models shows that CO2 reacts with 50% collision efficiency, while O2 reacts considerably slower. Nanocalorimetry yields internally consistent results for the three reactions. Converted to room temperature condensed phase, this yields hydration enthalpies of CO2˙(-) and O2˙(-), ΔHhyd(CO2˙(-)) = -334 ± 44 kJ mol(-1) and ΔHhyd(O2˙(-)) = -404 ± 28 kJ mol(-1). Quantum chemical calculations show that the charge exchange reaction proceeds via a CO4˙(-) intermediate, which is consistent with a fully ergodic reaction and also with the small efficiency. Ab initio molecular dynamics simulations corroborate this picture and indicate that the CO4˙(-) intermediate has a lifetime significantly above the ps regime.

  6. 呼气中挥发性硫化物的质子转移反应质谱在线检测%On-line Detection of Volatile Sulfur Compounds in Breath Gas by Proton Transfer Reaction Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    沈成银; 王鸿梅; 黄超群; 陆燕; 夏磊; 陈小景; 王宏志; 储焰南

    2015-01-01

    利用自主研制的高灵敏呼气检测质子转移反应质谱( PTR-MS),对一名口臭受试者的口腔吹出气体、鼻子呼出气体和口腔内气体分别进行多组分实时监测,发现了该受试者呼气中3种引起口臭的挥发性硫化物( VSCs)的来源并不相同,其中甲硫醇主要来源于口腔,硫化氢和二甲基硫则主要来源于肺或呼吸道。本研究不仅发现了口腔内气体在PTR-MS呼气监测过程中的特征变化趋势,还分析了呼出气体中3种VSCs的来源,对于呼气的正确采样和检测具有重要的指导意义。%To develop a kind of noninvasive method of breath diagnosis in diseases, much attention has been paid to the study of the relation between diseases and volatile organic compounds in human breath gas. However, the gas in oral cavity was usually ignored in many studies of breath gas. The bad breath odor of a participant was studied by a home-made proton transfer reaction mass spectrometer( PTR-MS) . The breath via the mouth, breath via the nose and the air in the mouth cavity were monitored with the mode of multiple ion detect scans. The results show that three different volatile sulfur compounds that cause bad breath odor should be attributed to different sources. The source of methyl mercaptan in breath is oral cavity, and the source of hydrogen sulphide and dimethylsulfide in breath is lung or respiratory tract. The related result is very important to sampling and detection of breath gas.

  7. Characterization of gas-phase organics using proton transfer reaction time-of-flight mass spectrometry: fresh and aged residential wood combustion emissions

    Science.gov (United States)

    Bruns, Emily A.; Slowik, Jay G.; El Haddad, Imad; Kilic, Dogushan; Klein, Felix; Dommen, Josef; Temime-Roussel, Brice; Marchand, Nicolas; Baltensperger, Urs; Prévôt, André S. H.

    2017-01-01

    Organic gases emitted during the flaming phase of residential wood combustion are characterized individually and by functionality using proton transfer reaction time-of-flight mass spectrometry. The evolution of the organic gases is monitored during photochemical aging. Primary gaseous emissions are dominated by oxygenated species (e.g., acetic acid, acetaldehyde, phenol and methanol), many of which have deleterious health effects and play an important role in atmospheric processes such as secondary organic aerosol formation and ozone production. Residential wood combustion emissions differ considerably from open biomass burning in both absolute magnitude and relative composition. Ratios of acetonitrile, a potential biomass burning marker, to CO are considerably lower ( ˜ 0.09 pptv ppbv-1) than those observed in air masses influenced by open burning ( ˜ 1-2 pptv ppbv-1), which may make differentiation from background levels difficult, even in regions heavily impacted by residential wood burning. A considerable amount of formic acid forms during aging ( ˜ 200-600 mg kg-1 at an OH exposure of (4.5-5.5) × 107 molec cm-3 h), indicating residential wood combustion can be an important local source for this acid, the quantities of which are currently underestimated in models. Phthalic anhydride, a naphthalene oxidation product, is also formed in considerable quantities with aging ( ˜ 55-75 mg kg-1 at an OH exposure of (4.5-5.5) × 107 molec cm-3 h). Although total NMOG emissions vary by up to a factor of ˜ 9 between burns, SOA formation potential does not scale with total NMOG emissions and is similar in all experiments. This study is the first thorough characterization of both primary and aged organic gases from residential wood combustion and provides a benchmark for comparison of emissions generated under different burn parameters.

  8. Transfer Pricing

    DEFF Research Database (Denmark)

    Nielsen, Søren Bo

    2014-01-01

    Against a background of rather mixed evidence about transfer pricing practices in multinational enterprises (MNEs) and varying attitudes on the part of tax authorities, this paper explores how multiple aims in transfer pricing can be pursued across four different transfer pricing regimes. A MNE h...

  9. 33 CFR 127.319 - LNG transfer.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false LNG transfer. 127.319 Section 127... Waterfront Facilities Handling Liquefied Natural Gas Operations § 127.319 LNG transfer. During LNG transfer operations, the following must be met: (a) The operator of the waterfront facility handling LNG shall...

  10. Heat and mass transfer of heated falling film under gas-liquid cross-flow condition%气液叉流下受热液膜的热质传递特性

    Institute of Scientific and Technical Information of China (English)

    蒋斌; 王子云; 付祥钊; 王勇

    2011-01-01

    采用VOF两相流模型研究了气液叉流条件下受热液膜热质传递特性,在模型中添加了表面张力源项和气液相间传质源项.为了验证所建立模型的可靠性,采用非接触式红外热成像测温方法,进行了相应的气液叉流试验.对叉流条件下受热液膜热质传递过程进行了试验和模拟计算,结果显示无量纲壁面温度计算结果与试验结果吻合很好.应用所建立的模型,模拟计算并分析了表面张力、固液接触角、液膜流量等因素对液膜流动侧形和热质传递性能的影响,结果表明:在其他参数保持不变的情况下,表面张力从0.014 N/m增大到0.072 N/m的过程中,液膜覆盖面积由82.7%减小到73.2%;固液接触角从30°增大到60°的过程中,液膜覆盖面积由80.6%减小到69.4%;液膜流量越小,液膜厚度越小,越有利于液膜的蒸发;相反,较高的液膜流量会使液膜厚度增大,阻碍了液膜蒸发,从而使外掠过液膜的单位体积空气含湿量减小.%Based on volume of fluid(VOF) method,heat and mass transfer of heated falling film under gas-liquid cross-flow condition was investigated. Surface tension and species transport were taken into account. In order to verify reliability of the model,the experiment was performed by non-contact infrared thermal imaging technology under gas-liquid cross-flow condition. Heat and mass transfer of heated falling film under gas-liquid cross-flow condition was investigated experimentally and theoretically. The results show that the simulated dimensionless wall temperature is in good agreement with the experimental data. Based on the model, the influence of surface tension coefficient, solid-liquid contact angle and liquid film flow rate on heat transfer of liquid film was simulated. It is found that, remaining constant of other parameters, liquid film interfacial area decreases from 82. 7% to 73. 2% in corresponding with surface tension coefficient increases

  11. Direct fired absorption machine flue gas recuperator

    Science.gov (United States)

    Reimann, Robert C.; Root, Richard A.

    1985-01-01

    A recuperator which recovers heat from a gas, generally the combustion gas of a direct-fired generator of an absorption machine. The recuperator includes a housing with liquid flowing therethrough, the liquid being in direct contact with the combustion gas for increasing the effectiveness of the heat transfer between the gas and the liquid.

  12. Numerical study on heat transfer of slot nozzles impinging gas-jet cooling process%带钢镀后喷射冷却过程传热特性的数值研究

    Institute of Scientific and Technical Information of China (English)

    黄军; 武文斐; 张亚竹; 李保卫; 牛德志

    2012-01-01

    Impinging gas-jet cooling is the most important cooling method in a continuous steel strip annealing and galvanizing production. Numerical simulation of a bellow and an array of slot nozzles impinging gas-jet has been performed through the solution of 3D Navier-Stokes equations and energy equation by using the SIMPLE algorithm and a standard k-e turbulence model. The simulation results reveal the characteristics of flow field and temperature field. Heat flux on strip surface distribution characteristics presented slit-like;the average convection heat transfer coefficient is 127.3W/(m2 · K) and strip cooling rate is 12.4℃/s by typical operating conditions. Provide theoretical basis for design of quick cooling system in continuous steel strip annealing and galvanizing production.%喷射气体冷却是带钢连续退火和镀后冷却过程中最重要的冷却方法,利用数值模拟方法对带钢镀后喷射冷却过程中带钢传热特性进行研究,计算结果表明在带钢表面热流密度呈条缝状分布,典型工况下带钢表面平均对流换热系数为127.3W/(m2·K),带钢冷却速度为12.4℃/s.该研究为带钢连续退火机组及镀后快冷系统设计提供理论依据.

  13. Control Strategies for Gas Transfer in Solid State Fermentation%固态发酵过程中气体传质控制策略的研究进展

    Institute of Scientific and Technical Information of China (English)

    夏永军; 王渊龙; 侯建平; 艾连中; 任婧

    2012-01-01

    Solid state fermentation has the obvious superiority in production of biologics and biological treatment process. Especially in recent years, with the development of theoretical model and bioreactors, the application range of solid state fermentation is growing fast. In aerobic solid state fermentation systems, oxygen mass transfer is often one of very important limiting factors for optimal growth and productivity. It is related to restriction of the scale-up of solid state fermentation. This paper reviews the phenomena of oxygen mass transfer process in macroscale and mi- croscale solid state fermentation system. It highlights several control strategies for improving gas transfer efficiency in solid state fermentation. The application prospects of solid state fermentation are discussed at the end of paper.%固态发酵在一些生物制品的生产及生物处理过程中具有明显的优势,特别是近年来随着对固态发酵理论模型和发酵设备的研究不断深入,固态发酵的应用范围越来越广。对于好氧的固态发酵来说,氧气的传质效率低仍然是工艺优化和提高产量的主要限制因素,同时它也影响了固态发酵生产规模的扩大。该文分析了固态发酵过程中气体传质的原理及过程,并对此提出了一些提高固态发酵过程中气体传质效率的策略,如控制固体基质特性、选择合适的搅拌通风方式等,最后展望了固态发酵技术的发展前景。

  14. Mesure et modélisation multidimensionnelle des transferts thermiques gaz-paroi dans le cas des moteurs à allumage commandé Measurement and Multidimensional Modeling of Gas-Wall Heat Transfers in Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Gilaber P.

    2006-11-01

    formulation k-epsilon de la turbulence a été adoptée. La sensibilité du modèle aux effets de densité et de turbulence a été testée par l'intermédiaire de variations de l'avance à l'allumage et du régime. La comparaison entre mesure et simulation a montré un bon accord, tant en termes de flux thermiques locaux et instantanés, qu'en termes de bilan global. The computational fluid dynamics codes, which help to predict the behaviour of combusting gas in reciprocating engines, need, as boundary conditions for the momentum and energy equations, to approximate wall frictions and heat transfer between gas and walls. The purpose of this work is to validate a heat transfer model for spark ignited engines. Two steps of research have been worked on to meet this objective: an experimental phase and a computational phase. In the experimental phase, measurements were made on a test-engine instrumented with fast-response surface heat flux gages. Each gage consisted of a steel cylinder, containing two thermocouples. To analyze the influence of fluid dynamics on heat transfer, a Laser Doppler Velocimeter was used, by means of a spacer placed between the engine head and cylinder. The spacer was equiped with two windows and two heat-flux gages permitting simultaneous measurements of the heat flux and of the fluid dynamics outside the boundary layer. Two other gages were present in the head of the engine and up to ten data inputs could be simultaneously recorded at each crank-angle, including two velocity components and the cylinder pressure. A parametric analysis was carried out revealing the following trends:- the global heat transfer rate for a thermodynamic cycle of the engine decreases as the speed of the engine is increased, but the peak value of the wall heat-flux increases because of the increase of the turbulence level. - the volumetric efficiency appeared to have little effect on the turbulence level, and its influence on the heat transfer is mainly due to the increase of

  15. Gas-phase chemical dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Weston, R.E. Jr.; Sears, T.J.; Preses, J.M. [Brookhaven National Laboratory, Upton, NY (United States)

    1993-12-01

    Research in this program is directed towards the spectroscopy of small free radicals and reactive molecules and the state-to-state dynamics of gas phase collision, energy transfer, and photodissociation phenomena. Work on several systems is summarized here.

  16. 天然气纯氧换热式转化工艺、催化剂及设备的应用%Use of Natural Gas Heat Transfer Reforming by Pure Oxygen Process, Catalyst and Equipment

    Institute of Scientific and Technical Information of China (English)

    魏有福

    2014-01-01

    介绍了天然气纯氧换热式转化装置的工艺流程、主要设备和催化剂应用情况。该装置设备材质及催化剂均实现国产化,运行状况良好。经多年节能挖潜改造,各项指标全面超过其设计值,吨氨消耗和综合能耗均低于Tandem工艺。%A introduction is given of the use of equipment and technological process for natural gas heat transfer reforming by pure oxygen, main equipment and catalyst.The material of the equipment and catalyst are realized localization, and the operation conditions are good.After many years of energy saving and tapping the potentials and transform, all indicators are excess their design values, consumption per ton ammonia and comprehensive energy consumption are lower than that of Tandem process.

  17. Mechanistic Study of the Gas-Phase In-Source Hofmann Elimination of Doubly Quaternized Cinchona-Alkaloid Based Phase-Transfer Catalysts by (+)-Electrospray Ionization/Tandem Mass Spectrometry

    Science.gov (United States)

    Yang, Rong-Sheng; Sheng, Huaming; Lexa, Katrina W.; Sherer, Edward C.; Zhang, Li-Kang; Xiang, Bangping; Helmy, Roy; Mao, Bing

    2017-01-01

    An unusual in-source fragmentation pattern observed for 14 doubly quaternized cinchona alkaloid-based phase-transfer catalysts (PTC) was studied using (+)-ESI high resolution mass spectrometry. Loss of the substituted benzyl cation (R1 or R2) was found to be the major product ion [M2+ - R1 + or R2 +]+ in MS spectra of all PTC compounds. A Hofmann elimination product ion [M - H]+ was also observed. Only a small amount of the doubly charged M2+ ions were observed in the MS spectra, likely due to strong Columbic repulsion between the two quaternary ammonium cations in the gas phase. The positive voltage in the MS inlet but not the ESI probe was found to induce this extensive fragmentation for all PTC diboromo-salts. Compound 1 was used as an example to illustrate the proposed in-source fragmentation mechanism. The mechanism of formation of the Hofmann elimination product ion [M - H]+ was further investigated using HRMS/MS, H/D exchange, and DFT calculations. The proposed formation of 2b as the major Hofmann elimination product ion was supported both by HRMS/MS and DFT calculations. Formation of product ion 2b through a concerted unimolecular Ei elimination pathway is proposed rather than a bimolecular E2 elimination pathway for common solution Hofmann eliminations.

  18. Gas turbine

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ok Ryong

    2004-01-15

    This book introduces gas turbine cycle explaining general thing of gas turbine, full gas turbine cycle, Ericson cycle and Brayton cycle, practical gas turbine cycle without pressure loss, multiaxial type gas turbine cycle and special gas turbine cycle, application of basic theory on a study on suction-cooling gas turbine cycle with turbo-refrigerating machine using the bleed air, and general performance characteristics of the suction-cooling gas turbine cycle combined with absorption-type refrigerating machine.

  19. Geo energy research and development: technology transfer

    Energy Technology Data Exchange (ETDEWEB)

    Traeger, R.K.

    1982-03-01

    Sandia Geo Energy Programs related to geothermal, coal, oil and gas, and synfuel resources have provided a useful mechanism for transferring laboratory technologies to private industry. Significant transfer of hardware, computer programs, diagnostics and instrumentation, advanced materials, and in situ process understanding has occurred through US/DOE supported programs in the past five years. The text briefly reviews the technology transfer procedures and summarizes 32 items that have been transferred and another 20 technologies that are now being considered for possible transfer to industry. A major factor in successful transfer has been personal interactions between Sandia engineers and the technical staff from private industry during all aspects of the technology development.

  20. Heat transfer, diffusion, and evaporation

    Science.gov (United States)

    Nusselt, Wilhelm

    1954-01-01

    Although it has long been known that the differential equations of the heat-transfer and diffusion processes are identical, application to technical problems has only recently been made. In 1916 it was shown that the speed of oxidation of the carbon in iron ore depends upon the speed with which the oxygen of the combustion air diffuses through the core of gas surrounding the carbon surface. The identity previously referred to was then used to calculate the amount of oxygen diffusing to the carbon surface on the basis of the heat transfer between the gas stream and the carbon surface. Then in 1921, H. Thoma reversed that procedure; he used diffusion experiments to determine heat-transfer coefficients. Recently Lohrisch has extended this work by experiment. A technically very important application of the identity of heat transfer and diffusion is that of the cooling tower, since in this case both processes occur simultaneously.

  1. Transfer Pricing

    DEFF Research Database (Denmark)

    Rohde, Carsten; Rossing, Christian Plesner

    trade internally as the units have to decide what prices should be paid for such inter-unit transfers. One important challenge is to uncover the consequences that different transfer prices have on the willingness in the organizational units to coordinate activities and trade internally. At the same time...

  2. Barrow Gas Field Transfer Act of 1984. Hearing before the Subcommittee on Public Lands and Reserved Water of the Committee on Energy and Natural Resources United States Senate, Ninety-Eighth Congress, Second Session on S. 2762 and H. R. 5740, June 22, 1984

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    Doyle G. Frederick of the Department of the Interior's Geological Survey was the principal witness at a hearing on S. 2762 and H.R. 5740, identical bills transferring ownership of the Barrow gas fields from the US government to the North Slope Borough. The hearing explored economic and political implications of the transfer as well as specific concerns about the details of its implementation. The testimony and an appendix with additional material submitted for the record follow the text of the two bills.

  3. Mathematical simulation of the process of condensing natural gas

    OpenAIRE

    Tastandieva G.M.

    2015-01-01

    Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG) storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the...

  4. 76 FR 4417 - Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application

    Science.gov (United States)

    2011-01-25

    ... Maritime Administration Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License.... Liberty Deepwater Port would receive and transfer natural gas from purpose-built LNG regasification... equipped to vaporize LNG cargo to natural gas through onboard closed loop vaporization systems and...

  5. Influência da tensão de soldagem e do gás de proteção sobre a correlação entre indutância e regularidade da transferência metálica na soldagem MIG/MAG por curto-circuito The influence of the welding voltage and of the shielding gas on the correlation between inductance and metal transfer regularity in short-circuiting MIG/MAG welding

    Directory of Open Access Journals (Sweden)

    Daniel Souza

    2011-06-01

    Full Text Available O processo de soldagem MIG/MAG operando no modo de transferência por curto-circuito é largamente utilizado quando se requer baixo aporte de calor. Porém, operando nesse modo, o processo pode apresentar excessiva geração de respingos. Para se minimizar este problema, é necessário atuar na regulagem de seus parâmetros. É sabido que a indutância governa a taxa de variação da corrente, com reflexos sobre a regularidade da transferência da gota por curto-circuito. Mas pouco se conhece sobre o efeito da regulagem da tensão e do uso de gases sobre essa taxa de variação. O objetivo deste trabalho foi avaliar a influência da tensão de soldagem e do gás de proteção na correlação entre a indutância e a regularidade da transferência por curto-circuito na soldagem MIG/MAG de aço carbono. Soldagens foram realizadas varrendo-se a regulagem de tensão em três valores diferentes de regulagem de indutância e com dois gases de proteção, mantendo-se a corrente média constante. Um critério quantitativo foi utilizado para medição da regularidade da transferência. Condições de transferência foram visualizadas por meio de perfilografia sincronizada com filmagem de alta velocidade. Resultados mostraram que a tensão de soldagem e o gás de proteção não influenciaram as taxas de variação da corrente para uma mesma regulagem da indutância, mas que mesmo assim a regularidade do processo é dependente do gás de proteção e da tensão de soldagem.The MIG/MAG process operating as short-circuiting is widely used when low heat input is a demand. However, in this operating mode, excessive spattering may occur. To mitigate this problem, it is necessary to act on parameter settings. It is known that inductance governs the current increasing/decreasing rate, reflecting on the short-circuiting transfer regularity. However, little is known about the effect of arc voltage and the gas composition on this rate. Thus, in this work it was

  6. "Transfer Shock" or "Transfer Ecstasy?"

    Science.gov (United States)

    Nickens, John M.

    The alleged characteristic drop in grade point average (GPA) of transfer students and the subsequent rise in GPA was investigated in this study. No statistically significant difference was found in first term junior year GPA between junior college transfers and native Florida State University students after the variance accounted for by the…

  7. Heat Transfer and Cooling in Gas Turbines

    Science.gov (United States)

    1985-09-01

    refroidiuseiment de virole & vtrole, GCt effet de cutul est naturellement d’autant mieux r~alis6 que I’effieacit6 unitaire de chaque film eat importante. La...ftre remplie grace A lenregistrement sur le magnutique d’un top par tour delivre par un capteur magnetique dont l’un des ergots eat our le rotor et...conditions optimales. A cet effet un capteur capacitif est en cours de dfveloppement A I’ONERA et lea risoltats obtenus, compares A un appareil de

  8. Nonlinear analysis of thermal stresses of a of first stage nozzle of a gas turbine at full load from the results of an analysis of conjugated heat transference; Analisis no lineal de esfuerzos termicos de una tobera de primera etapa de turbina de gas a plena carga a partir de resultados de un analisis de transferencia de calor conjugado

    Energy Technology Data Exchange (ETDEWEB)

    Perez Hernandez, Efrain [Centro Nacional de Investigacion y Desarrollo Tecnologico (Cenidet), Cuernavaca, Morelos (Mexico); Mazur C, Zdzislaw; Garcia Illescas, R; Hernandez Rossette, Alejandro [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2007-11-15

    The gas turbines operate at extremely high temperatures, at high thermal and mechanical stresses, causing that the useful life of the involved components be reduced. In the present article the results realized by previous investigations of temperatures obtained from analysis of heat transfer and flow of fluids of the nozzle by means of the Star-CD program based on finite volumes is presented. Later, the NISA program of finite elements was used to realize the analysis of thermal stresses considering the material plasticity. The methodology employed to determine the material properties variable with the temperature of the super-alloy FSX-414 and the plasticity model used in the structural analysis in the finite element program. The result will be later used in the fatigue analysis for the useful life assessment. [Spanish] Las turbinas de gas operan a temperatura extremadamente altas, a elevados esfuerzos termicos y mecanicos, ocasionando que la vida de los componentes involucrados se reduzca. En el presente articulo se presentan los resultados realizados por previas investigaciones de temperaturas obtenidas a partir de analisis de transferencia de calor y flujo de fluidos de la tobera mediante el programa Star-CD basado en volumenes finitos. Posteriormente, se utilizo el programa NISA de elementos finitos para realizar el analisis de esfuerzos termicos considerando plasticidad del material. Se muestra la metodologia empleada para determinar las propiedades del material variables con la temperatura de la superaleacion FSX-414 y el modelo de plasticidad utilizado en el analisis estructural en el programa de elemento finito. Los resultados seran empleados posteriormente en el analisis de fatiga para la estimacion de vida util.

  9. Mass Transfer Method and Apparatus

    DEFF Research Database (Denmark)

    1995-01-01

    .g. polytetrafluoroethylene (PTFE, Teflon $m(3)) membranes, in the form of hollow fibres having gas-containing pores and contacting the second fluid with the inner surface of the membranes. Useful membranes are characterized in that they e.g. have a porosity ($g(e)) of at least 0.50, a mass transfer coefficient of e...

  10. 33 CFR 127.1203 - Gas detection.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Gas detection. 127.1203 Section... Waterfront Facilities Handling Liquefied Hazardous Gas Equipment § 127.1203 Gas detection. (a) Each... LHG that transfers a toxic LHG, other than anhydrous ammonia, must have at least two portable...

  11. Elements of heat transfer

    CERN Document Server

    Rathakrishnan, Ethirajan

    2012-01-01

    1 Basic Concepts and Definitions1.1 Introduction1.1.1 Driving Potential1.2 Dimensions and Units1.2.1 Dimensional Homogeneity1.3 Closed and Open Systems1.3.1 Closed System (ControlMass)1.3.2 Isolated System1.3.3 Open System (ControlVolume)1.4 Forms of Energy1.4.1 Internal Energy1.5 Properties of a System1.5.1 Intensive and Extensive Properties1.6 State and Equilibrium1.7 Thermal and Calorical Properties1.7.1 Specific Heat of an Incompressible Substance1.7.2 Thermally Perfect Gas 1.8 The Perfect Gas1.9 Summary1.10 Exercise ProblemsConduction Heat Transfer2.1 Introduction2.2 Conduction Heat Trans

  12. A Simple Experiment for Mass Transfer.

    Science.gov (United States)

    Rodriguez, Jesus M.; Henriquez, Vicente; Macias-Machin, Agustin

    1998-01-01

    Presents an experiment in which students use laboratory data to calculate the interphase mass transfer coefficient for a fluid passed over a sphere and obtain correlations for solid-gas mass transfer. Students develop a realistic mathematical model to describe the sublimation process. (DDR)

  13. Technology Transfer

    Science.gov (United States)

    Smith, Nanette R.

    1995-01-01

    The objective of this summer's work was to attempt to enhance Technology Application Group (TAG) ability to measure the outcomes of its efforts to transfer NASA technology. By reviewing existing literature, by explaining the economic principles involved in evaluating the economic impact of technology transfer, and by investigating the LaRC processes our William & Mary team has been able to lead this important discussion. In reviewing the existing literature, we identified many of the metrics that are currently being used in the area of technology transfer. Learning about the LaRC technology transfer processes and the metrics currently used to track the transfer process enabled us to compare other R&D facilities to LaRC. We discuss and diagram impacts of technology transfer in the short run and the long run. Significantly, it serves as the basis for analysis and provides guidance in thinking about what the measurement objectives ought to be. By focusing on the SBIR Program, valuable information regarding the strengths and weaknesses of this LaRC program are to be gained. A survey was developed to ask probing questions regarding SBIR contractors' experience with the program. Specifically we are interested in finding out whether the SBIR Program is accomplishing its mission, if the SBIR companies are providing the needed innovations specified by NASA and to what extent those innovations have led to commercial success. We also developed a survey to ask COTR's, who are NASA employees acting as technical advisors to the SBIR contractors, the same type of questions, evaluating the successes and problems with the SBIR Program as they see it. This survey was developed to be implemented interactively on computer. It is our hope that the statistical and econometric studies that can be done on the data collected from all of these sources will provide insight regarding the direction to take in developing systematic evaluations of programs like the SBIR Program so that they can

  14. Blastocyst Transfer

    OpenAIRE

    sprotocols

    2014-01-01

    ### Method: Blastocyst transfer is usually performed 24 hours after aggregation when the morulae have become expanded blastocysts and on the same day as injection. A little time is given between injection and transfer to allow blastocysts to re-expand. **The Recipient** Careful selection of the recipient is most important as the pups are the end result of a lot of hard work. Two strains of mice are used:RB Swiss and (CBA*C57BL6/J)f1. RB Swiss are quiet and make excellent mothers ...

  15. Heat transfer

    CERN Document Server

    Holman, J P

    2010-01-01

    As one of the most popular heat transfer texts, Jack Holman's "Heat Transfer" is noted for its clarity, accessible approach, and inclusion of many examples and problem sets. The new tenth edition retains the straight-forward, to-the-point writing style while covering both analytical and empirical approaches to the subject. Throughout the book, emphasis is placed on physical understanding while, at the same time, relying on meaningful experimental data in those situations that do not permit a simple analytical solution. New examples and templates provide students with updated resources for computer-numerical solutions.

  16. The performance of a new gas to gas heat exchanger with strip fin

    NARCIS (Netherlands)

    Wang, J.; Hirs, G.G.; Rollmann, P.

    1999-01-01

    A compact gas to gas heat exchanger needs large heat transfer areas on both fluid sides. This can be realised by adding secondary surfaces. The secondary surfaces are plate fin, strip fin, and louvered fin, etc. The fins extend the heat transfer surfaces and promote turbulence. This paper presents

  17. Transfer Entropy Analysis of the Stock Market

    CERN Document Server

    Baek, S K; Kwon, O; Moon, H T; Baek, Seung Ki; Jung, Woo-Sung; Kwon, Okyu; Moon, Hie-Tae

    2005-01-01

    In terms of transfer entropy, we investigated the strength and the direction of information transfer in the US stock market. Through the directionality of the information transfer, the more influential company between the correlated ones can be found and also the market leading companies are selected. Our entropy analysis shows that the companies related with energy industries such as oil, gas, and electricity influence the whole market.

  18. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  19. Fundamentals of gas particle flow

    CERN Document Server

    Rudinger, G

    1980-01-01

    Fundamentals of Gas-Particle Flow is an edited, updated, and expanded version of a number of lectures presented on the "Gas-Solid Suspensions” course organized by the von Karman Institute for Fluid Dynamics. Materials presented in this book are mostly analytical in nature, but some experimental techniques are included. The book focuses on relaxation processes, including the viscous drag of single particles, drag in gas-particles flow, gas-particle heat transfer, equilibrium, and frozen flow. It also discusses the dynamics of single particles, such as particles in an arbitrary flow, in a r

  20. Analysis of carbondioxide anti-sublimation heat transfer in natural gas flow in a tube heat exchanger under the third class boundary condition%第三类边界条件下套管内天然气中CO2凝华换热分析

    Institute of Scientific and Technical Information of China (English)

    刘瑶; 林文胜

    2012-01-01

    Taking the idea that removing carbondioxide by anti-sublimation in a pressurized liquefied natural gas (PLNG) process as the background, carbondioxide anti-sublimation heat transfer in natural gas flow in a tube heat exchanger was analyzed. Natural gas was simplified as methane + carbondioxide binary mixture. The mixture flows in the inner tube while being cooled by cold nitrogen in the outer tube, and carbondioxide was formed by anti-sublimation. A mathematical model of this heat transfer process was built, and the fourth-order Runge-Kutta method was used to solve the differential equations. The affects of flow velocity for natural gas and nitrogen, the inlet carbondioxide concentration, the temperature of inlet nitrogen, and the length of the tube heat exchanger on the carbondioxide anti-sublimation heat transfer process were analyzed under the third class boundary condition.%针对带压液化天然气( PLNG)流程中对高二氧化碳含量天然气进行二氧化碳凝华分离的设想,分析了天然气中二氧化碳在套管内的凝华换热.将天然气简化为甲烷+二氧化碳的二元混合物,该混合物在固管内流动,被管外冷氮气冷却直至其中二氧化碳凝华析出.建立了该传热过程的数学模型,采用四阶Runge-Kutta法求解微分方程,分析了天然气和氮气流速、二氧化碳进口体积分数、氮气进口温度、管长对第三类边界条件下凝华换热过程的影响.

  1. Sophisticated transfer

    NARCIS (Netherlands)

    Reinhart, T.

    2006-01-01

    On the eve of the Iraq war, fears were expressed in different circles that under the cover of war, Israel may attempt a transfer of Palestinians in the “seam line” area of the northern West Bank (Kalkilya, Tulkarem). Last week, the army produced a scene from this scenario. On April 2 at 3 AM, a larg

  2. Facilitating Transfers

    DEFF Research Database (Denmark)

    Kjær, Poul F.

    that the essential functional and normative purpose of regulatory governance is to facilitate, stabilise and justify the transfer of condensed social components (such as economic capital and products, political decisions, legal judgements, religious beliefs and scientific knowledge) from one social contexts...

  3. Modeling microscale heat transfer using Calore.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Rader, Daniel John; Wong, Chung-Nin Channy; Bainbridge, Bruce L.; Torczynski, John Robert; Piekos, Edward Stanley

    2005-09-01

    Modeling microscale heat transfer with the computational-heat-transfer code Calore is discussed. Microscale heat transfer problems differ from their macroscopic counterparts in that conductive heat transfer in both solid and gaseous materials may have important noncontinuum effects. In a solid material, three noncontinuum effects are considered: ballistic transport of phonons across a thin film, scattering of phonons from surface roughness at a gas-solid interface, and scattering of phonons from grain boundaries within the solid material. These processes are modeled for polycrystalline silicon, and the thermal-conductivity values predicted by these models are compared to experimental data. In a gaseous material, two noncontinuum effects are considered: ballistic transport of gas molecules across a thin gap and accommodation of gas molecules to solid conditions when reflecting from a solid surface. These processes are modeled for arbitrary gases by allowing the gas and solid temperatures across a gas-solid interface to differ: a finite heat transfer coefficient (contact conductance) is imposed at the gas-solid interface so that the temperature difference is proportional to the normal heat flux. In this approach, the behavior of gas in the bulk is not changed from behavior observed under macroscopic conditions. These models are implemented in Calore as user subroutines. The user subroutines reside within Sandia's Source Forge server, where they undergo version control and regression testing and are available to analysts needing these capabilities. A Calore simulation is presented that exercises these models for a heated microbeam separated from an ambient-temperature substrate by a thin gas-filled gap. Failure to use the noncontinuum heat transfer models for the solid and the gas causes the maximum temperature of the microbeam to be significantly underpredicted.

  4. Gas Hydrate Storage of Natural Gas

    Energy Technology Data Exchange (ETDEWEB)

    Rudy Rogers; John Etheridge

    2006-03-31

    lower heat transfer rate in the internal heat exchanger than was designed. It is believed that the fins on the heat-exchanger tubes did not make proper contact with the tubes transporting the chilled glycol, and pairs of fins were too close for interior areas of fins to serve as hydrate collection sites. A correction of the fabrication fault in the heat exchanger fin attachments could be easily made to provide faster formation rates. The storage success with the POC process provides valuable information for making the process an economically viable process for safe, aboveground natural-gas storage.

  5. Radiation heat transfer shapefactors for combustion systems

    Science.gov (United States)

    Emery, A. F.; Johansson, O.; Abrous, A.

    1987-01-01

    The computation of radiation heat transfer through absorbing media is commonly done through the zoning method which relies upon values of the geometric mean transmittance and absorptance. The computation of these values is difficult and expensive, particularly if many spectral bands are used. This paper describes the extension of a scan line algorithm, based upon surface-surface radiation, to the computation of surface-gas and gas-gas radiation transmittances.

  6. Carbon monoxide transfer in pig lungs during mechanical ventilation

    NARCIS (Netherlands)

    F.C.A.M. te Nijenhuis (Frances)

    1996-01-01

    textabstractThis thesis comprises studies of gas transfer in the lungs during mechanical ventilation, which have been obtained in healthy pigs. The objectives of this thesis were: I) to adapt the breath-holding teclmique, as used during spontaneous breathing for estimation of gas transfer, to condit

  7. 75 FR 70350 - Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License Application

    Science.gov (United States)

    2010-11-17

    ... Maritime Administration Liberty Natural Gas LLC, Liberty Liquefied Natural Gas (LNG) Deepwater Port License... receive and transfer natural gas from purpose-build LNG regasification vessels (LNGRVs) with a total cargo tank capacity of approximately 145,000 m\\3\\. The vessels would be equipped to vaporize LNG cargo...

  8. Gas treating absorption theory and practice

    CERN Document Server

    Eimer, Dag

    2014-01-01

    Gas Treating: Absorption Theory and Practice provides an introduction to the treatment of natural gas, synthesis gas and flue gas, addressing why it is necessary and the challenges involved.  The book concentrates in particular on the absorption-desorption process and mass transfer coupled with chemical reaction. Following a general introduction to gas treatment, the chemistry of CO2, H2S and amine systems is described, and selected topics from physical chemistry with relevance to gas treating are presented. Thereafter the absorption process is discussed in detail, column hardware is explain

  9. Natural Gas and Indoor Air Pollution: A Comparison With Coal Gas and Liquefied Petroleum Gas

    Institute of Scientific and Technical Information of China (English)

    YUE ZHANG; BAO-SHENG CHEN; GUANG-QUAN LIU; JU-NING WANG; ZHEN-HUA ZHAO; LIAN-QING LIN

    2003-01-01

    The study was designed to compare the combustion products of coal gas, liquefied petroleum gas and natural gas in relation to indoor air pollution. Methods Regular pollutants including B(a)P were monitored and 1-hydroxy pyrene were tested in urine of the enrolled subjects.Radon concentrations and their changes in four seasons were also monitored in the city natural gas from its source plant and transfer stations to final users. To analyze organic components of coal gas,liquefied petroleum gas and natural gas, a high-flow sampling device specially designed was used to collect their combustion products, and semi-volatile organic compounds contained in the particles were detected by gas chromatograph-mass spectrograph (GC/MS). Results Findings in the study showed that the regular indoor air pollutants particles and CO were all above the standard in winter when heating facilities were operated in the city, but they were lowest in kitchens using natural gas;furthermore, although NO2 and CO2 were slightly higher in natural gas, B(a)P concentration was lower in this group and 1-hydroxy pyrene was lowest in urine of the subjects exposed to natural gas.Organic compounds were more complicated in coal gas and liquefied petroleum gas than in natural gas. The concentration of radon in natural gas accounted for less than 1‰ of its effective dose contributing to indoor air pollution in Beijing households. Conclusion Compared to traditional fuels, gases are deemed as clean ones, and natural gas is shown to be cleaner than the other two gases.

  10. Mathematical simulation of the process of condensing natural gas

    Directory of Open Access Journals (Sweden)

    Tastandieva G.M.

    2015-01-01

    Full Text Available Presents a two-dimensional unsteady model of heat transfer in terms of condensation of natural gas at low temperatures. Performed calculations of the process heat and mass transfer of liquefied natural gas (LNG storage tanks of cylindrical shape. The influence of model parameters on the nature of heat transfer. Defined temperature regimes eliminate evaporation by cooling liquefied natural gas. The obtained dependence of the mass flow rate of vapor condensation gas temperature. Identified the possibility of regulating the process of “cooling down” liquefied natural gas in terms of its partial evaporation with low cost energy.

  11. moisture transfer

    Directory of Open Access Journals (Sweden)

    Don Kulasiri

    2005-01-01

    model drying porous materials. Coupled partial differential equations governing the moisture and heat transfer can be solved using numerical techniques, and in this paper we solve them analytically in a setting suitable for industrial drying situations. We discuss the nature of the solutions using the physical properties of Pinus radiata. It is shown that the temperature gradients play a significant role in deciding the moisture profiles within the material when thickness is large and that models based only on moisture potential gradients may not be sufficient to explain the drying phenomena in moist porous materials.

  12. Heat transfer

    CERN Document Server

    Jorge, Kubie; Thomas, Grassie

    2012-01-01

    A core task of engineers is to analyse energy related problems. The analytical treatment is usually based on principles of thermodynamics, fluid mechanics and heat transfer, but is increasingly being handled computationally.This unique resource presents a practical textbook, written for both undergraduates and professionals, with a series of over 60 computer workbooks on an accompanying CD.The book emphasizes how complex problems can be deconstructed into a series of simple steps. All thermophysical property computations are illustrated using diagrams within text and on the compani

  13. Gas Storage Technology Consortium

    Energy Technology Data Exchange (ETDEWEB)

    Joel Morrison; Elizabeth Wood; Barbara Robuck

    2010-09-30

    The EMS Energy Institute at The Pennsylvania State University (Penn State) has managed the Gas Storage Technology Consortium (GSTC) since its inception in 2003. The GSTC infrastructure provided a means to accomplish industry-driven research and development designed to enhance the operational flexibility and deliverability of the nation's gas storage system, and provide a cost-effective, safe, and reliable supply of natural gas to meet domestic demand. The GSTC received base funding from the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) Oil & Natural Gas Supply Program. The GSTC base funds were highly leveraged with industry funding for individual projects. Since its inception, the GSTC has engaged 67 members. The GSTC membership base was diverse, coming from 19 states, the District of Columbia, and Canada. The membership was comprised of natural gas storage field operators, service companies, industry consultants, industry trade organizations, and academia. The GSTC organized and hosted a total of 18 meetings since 2003. Of these, 8 meetings were held to review, discuss, and select proposals submitted for funding consideration. The GSTC reviewed a total of 75 proposals and committed co-funding to support 31 industry-driven projects. The GSTC committed co-funding to 41.3% of the proposals that it received and reviewed. The 31 projects had a total project value of $6,203,071 of which the GSTC committed $3,205,978 in co-funding. The committed GSTC project funding represented an average program cost share of 51.7%. Project applicants provided an average program cost share of 48.3%. In addition to the GSTC co-funding, the consortium provided the domestic natural gas storage industry with a technology transfer and outreach infrastructure. The technology transfer and outreach were conducted by having project mentoring teams and a GSTC website, and by working closely with the Pipeline Research Council International (PRCI) to

  14. Compact exhaust gas boilers. Investigation of heat transfer and pressure drop for serrated finned tubes. (Abbreviated edition); Kompakte avgasskjeler. Undersoekelse av varmeovergang og trykktap for serraterte finnede roer. (Forkortet utgave.)

    Energy Technology Data Exchange (ETDEWEB)

    Midtbust, H.O.; Naess, E.

    1995-07-03

    This report discusses investigations of pressure drops and heat transfer in cross-current flow of gases (air) on bundles of serrated finned tubes. For the various geometries the tube spacing and tube diameter varied while the geometry of the fins remained unchanged. Pressure drop and heat transfer were measured at six different air flows for each geometry, and the results compared with available correlations from the literature. The measurements are at variance with the correlations and indicate that the pressure loss coefficient for all the tested geometries are less influenced by the flow conditions (air speed) than predicted by the correlations. Compared with the correlation recommended by the tube supplier (Weierman`s correlation) the measured results are mostly somewhat higher than predicted for the larger air flows. The maximum observed deviation is 70%. The deviation between the published pressure loss correlations is also considerable. The heat transfer measurements agree qualitatively with the published correlations with respect to the flow conditions. Comparison with the heat transfer correlation recommended by the tube supplier indicates that the correlation over-predicts the heat transfer quite considerably. The deviation increases systematically with reduced tube diameter and with increased angle of the tube arrangement. 16 figs., 7 tabs.

  15. Momentum transfer by astrophysical jets

    CERN Document Server

    Chernin, L M; De Gouveia dal Pino, E M; Benz, W

    1994-01-01

    We have used 3-D smoothed particle hydrodynamical simulations to study the basic properties of the outflow that is created by a protostellar jet in a dense molecular cloud. The dynamics of the jet/cloud interaction is strongly affected by the cooling in the shocked gas behind the bow shock at the head of the jet. We show that this cooling is very rapid, with the cooling distance of the gas much less than the jet radius. Thus, although ambient gas is initially driven away from the jet axis by the high thermal pressure odf the post-shock gas, rapid cooling reduces the pressure and the outflow subsequently evolves in a momentum-conserving snowplow fashion. The velocity of the ambient gas is high in the vicinity of the jet head, but decreases rapidly as more material is swept up. Thus, this type of outflow produces extremely high velocity clumps of post shock gas which resemble the features seen in outflows. We have investigated the transfer of momentum from the jet to the ambient medium as a function of the jet ...

  16. Modeling ozone mass transfer in reclaimed wastewater.

    Science.gov (United States)

    Jiang, Pan; Chen, Hsiao-Ting; Babcock, Roger W; Stenstrom, Michael K

    2009-01-01

    Ozone mass transfer in reclaimed water was evaluated at pilot scale to determine mass-transfer characteristics and reaction kinetics and to assess the use of oxygen as a surrogate to measure this process. Tests were conducted in a 40-L/min pilot plant over a 3-year period. Nonsteady-state mass-transfer analyses for both oxygen and ozone were performed for superficial gas flow rates ranging from 0.13m/min to 0.40m/min. The psi factor, which is the ratio of volumetric mass-transfer coefficients of ozone to oxygen, was determined. The decrease in oxygen transfer rate caused by contaminants in reclaimed water was only 10 to 15% compared to tap water. A simple mathematical model was developed to describe transfer rate and steady state ozone concentration. Ozone decay was modeled accurately as a pseudo first-order reaction between ozone and ozone-demanding materials.

  17. 载体内循环膜分离反应器的水力学性质及气液传质特性研究%Study on the Hydrodynamic Property and Gas-liquid Mass Transfer Efficiency in a Membrane Separation Reactor with Inner-loop Carriers

    Institute of Scientific and Technical Information of China (English)

    谭显东; 羊依金; 刘建英; 黄健盛; 赵洪兵; 杨平

    2009-01-01

    The hydrodynamic property and gas-liquid mass transfer efficiency of membrane separation reactor with inner-loop carriers was studied in the tap water test. The result showed that the critical gas velocity needed by cir-culation fluidization state was 6.2~7.7 m/h when the carrier holdup and liquid flow were 2%~8% and 0 ~16 L/ h, respectively. After the carrier was added, the gas holdup and oxygen transfer coefficient can be improved with the increase of gas velocity and be reduced with increase of carrier holdup. Gas holdup was 0.65% ~ 3.5% and oxygen transfer coefficient was 8.3 2 ~ 2 8.0 h~(-1) when carrier holdup, liquid flow and gas velocity were 0 ~ 6 % , 5.3 L/h and 7.5 ~ 30.1 m/h, respectively . The circulating time and mixing time can be reduced with increase of gas velocity and carrier holdup. The circulating time was 2.9 ~34 s and mixing time was 10.2 ~41.9 s when carri-er holdup, liquid flow and gas velocity were 0~ 6%, 5.3 L/h and 3.8 ~ 22.6 m/h, respectively.%通过清水实验考察了载体内循环膜分离反应器的水力学性质及气液传质性能.结果表明,在固相含率为2%~8%、液流量为0~16L/h时,反应器达到循环流态化需要的临界气速为6.2~7.7 m/h;投加载体后,气相含率和氧传质系数随着气速的增加而增大,随着固相含率的增加而减小,在固相含率为0~6%、液流量为5.3 L/h、气速为7.5~30.1 m/h时,反应器的气相含率介于0.65%~3.5%之间,氧传质系数在8.32~28.0 h~(-1)之间变化;循环时间和混合时间都随着气速及固相含率的增加而减小,在固相含率为0~6%、液流量为5.3 L/h、气速为3.8~22.6 m/h时,循环时间为2.9-34 s,混合时间为10.2~41.9s.

  18. Local liquid side mass transfer model in gas-liquid-solid three-phase flow airlift loop reactor for Newtonian and non-Newtonian fluids%气-液-固三相气升式环流反应器中牛顿型及非牛顿型流体局部液相传质模型

    Institute of Scientific and Technical Information of China (English)

    闻建平; 贾晓强; 毛国柱

    2004-01-01

    A small scale isotropic mass transfer model was developed for the local liquid side mass transfer coefficients in gas-liquid-solid three-phase flow airlift loop reactor for Newtonian and non-Newtonian fluids.It is based on Higbie's penetration theory and Kolmogoroff's theory of isotropic turbulence with k1 = 3√2Dε1/3 1/π(η-1/3 1 -λ-1/3 f),where ε1 is local rate of energy dissipation,λf is the local microscale,η1 is the local Kolmogoroff scale and D is the diffusion coefficient.The capability of the proposed model is discussed in the light of experimental data obtained from 12 L gas-liquid-solid three-phase flow airlift loop reactor using Newtonian and non-Newtonian fluids.Good agreement with the experimental data was obtained over a wide range of conditions suggesting a general applicability of the proposed model.

  19. Requirements for gas quality and gas appliances

    NARCIS (Netherlands)

    Levinsky, Howard; Gersen, Sander; Kiewiet, Bert

    2015-01-01

    Introduction The gas transmission network in the Netherlands transports two different qualities of gas, low-calorific gas known as G-gas or L-gas and, high calorific gas (H-gas). These two gas qualities are transported in separate networks, and are connected by means of five blending and conversion

  20. Gas chromatography

    Science.gov (United States)

    Guiochon, Georges; Guillemin, Claude L.

    1990-11-01

    Gas chromatography is a powerful separation technique for gas and vapor mixtures. Combining separation and on-line detection permits accurate quantitative analysis of complex mixtures, including traces of compounds down to parts per trillions in some particular cases. The importance of gas chromatography in quality control and process control in the chemical and drug industry, in environmental pollution investigations and in clinical analysis is critical. The principles of the technique are discussed, the main components of a gas chromatograph are described and some idea of the importance of the applications is given.

  1. Gas magnetometer

    Science.gov (United States)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  2. Gas magnetometer

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert

    2016-05-03

    Measurement of a precessional rate of a gas, such as an alkali gas, in a magnetic field is made by promoting a non-uniform precession of the gas in which substantially no net magnetic field affects the gas during a majority of the precession cycle. This allows sensitive gases that would be subject to spin-exchange collision de-phasing to be effectively used for extremely sensitive measurements in the presence of an environmental magnetic field such as the Earth's magnetic field.

  3. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-04-01

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

  4. ADVANCED GAS TURBINE SYSTEMS RESEARCH

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2002-02-01

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

  5. Heat transfer between graphene and amorphous SiO2.

    Science.gov (United States)

    Persson, B N J; Ueba, H

    2010-11-24

    We study the heat transfer between graphene and amorphous SiO(2). We include both the heat transfer from the area of real contact, and between the surfaces in the non-contact region. We consider the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies, and the heat transfer by the gas in the non-contact region. We find that the dominant contribution to the heat transfer results from the area of real contact, and the calculated value of the heat transfer coefficient is in good agreement with the value deduced from experimental data.

  6. The Subscale Orbital Fluid Transfer Experiment

    Science.gov (United States)

    Meserole, J. S.; Collins, Frank G.; Jones, Ogden; Antar, Basil; Menzel, Reinhard; Gray, Perry

    1989-01-01

    The Center for Advanced Spacecraft Propulsion (CASP) is a subcontractor to Boeing Aerospace Corporation to provide support for the concept definition and design of a subscale orbital fluid transfer experiment (SOFTE). SOFTE is an experiment that will look at the fluid mechanics of the process of transfer of a saturated fluid between two tanks. The experiment will be placed in two get away special (GAS) can containers; the tanks will be in one container and the power and electronics will be in a second container. Since GAS cans are being used, the experiment will be autonomous. The work during the present year consisted of examining concepts for visual observation of the fluid transfer process, methods for accurately metering the amount of fluid transferred between the two tanks, possible test fluids, and materials for the elastomeric diaphragm.

  7. 油气集输过程中低温余热利用热泵技术的概述%Overview of the Heat Pump Technology for Low Temperature Waste Heat Utilization of Oil and Gas Gathering and Transferring Process

    Institute of Scientific and Technical Information of China (English)

    王辉; 吴明

    2015-01-01

    当前在油气集输系统中,低温(40~50℃)余热资源非常的丰富,造成了很大能源浪费和热“污染”。改善能源的利用效率,对于解决能源危机非常的关键。热泵是油气集输系统中低温余热进行回收的核心装置,其不仅能够提高能源品味,还具有操作简单,技术较成熟的特点。分析了油气集输系统的用能状况和能源消耗的原因,还论述了低温余热回收热泵技术和对热泵市场进行介绍。%Recently,in the process of oil and gas gatheringand transferring, the resourceoflow temperature waste heat isveryabundant. Andithascaused a lot of energy waste and thermal pollution.The key to solve the energy crisis isto improve energy efficiency .Theheatpump is thecore equipmentforthe low temperature waste heat recovery in the oil and gas gathering and transferringprocess.Ithas manyadvantages, suchassimpleoperation, maturetechnologyand soon.In thispaper,the condition of energy use and the reasonsof energy consumption in the oil and gas gathering and transferring systemwereanalyzed;theheat pump technologyforlow temperature waste heat recoverywasdiscussed, andthe market of the heatpumpwas alsointroduced.

  8. Mass transfer coefficients in metallurgical reactors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An overview on the application and achievements of physico-mathematical modeling of metallurgical processes in Chinais briefly declared. The important role of coefficients in model formulation is shown from our experience. The mass transfer coeffi-cients of the slag-metal reactions and the gas-metal reactions are discussed referring to the flow conditions near the interface. Theinfluence of the surface-active species on the mass transfer and the inteffacial reaction is also discussed briefly.

  9. Development of a cryogenic flexible pipe for the transfer of liquefied natural gas; Mise au point d'un flexible cryogenique pour le transfert du gaz naturel liquefie

    Energy Technology Data Exchange (ETDEWEB)

    Rigaud, J.; Gerez, J.M.; Dieumegard, C. [Coflexip Stena Offshore, 75 - Paris (France)

    2000-07-01

    For historical reasons, the liquefaction of natural gas is performed with onshore equipments and LNG tanker-ships are loaded and unloaded using rigid articulated arms. When these operations are performed in harbors, the movement of the ship with respect to the pier are relatively limited. Today, several companies aim at liquefying natural gas using floating facilities. The loading of tanker-ships is performed offshore, and thus movements between the ship and the floating facility are enhanced. The use of a flexible pipe can be an interesting alternative solution to the articulated arm. This article describes the state-of-the-art of the LNG flexible technology developed by Coflexip Stena Offshore and the progress of the program of development of a cryogenic flexible: structure, fittings, safety (leaks detection), thermal calculations, optimization of the corrugated hose profile, pressure drops, fatigue tests and service life, materials development, prototype and real tests. (J.S.)

  10. MATHEMATICAL MODELING OF THERMOPHYSICAL PARAMETERS OF VORTEX HEAT EXCHANGER OF HEATING SYSTEMS OF GAS DISTRIBUTION POINTS PREMISES

    Directory of Open Access Journals (Sweden)

    V. A. Lapin

    2009-09-01

    Full Text Available The mathematical model of heat transfer in vortex heat exchanger using natural gas energy which is released under decompression in gas-main pipe-lines for consumers of gas supply systems (dwellings, public and industrial buildings.

  11. Transferable Tight-Binding Potential for Hydrocarbons

    CERN Document Server

    Wang, Y; Wang, Yang

    1994-01-01

    A transferable tight-binding potential has been constructed for heteroatomic systems containing carbon and hydrogen. The electronic degree of freedom is treated explicitly in this potential using a small set of transferable parameters which has been fitted to small hydrocarbons and radicals. Transferability to other higher hydrocarbons were tested by comparison with ab initio calculations and experimental data. The potential can correctly reproduce changes in the electronic configuration as a function of the local bonding geometry around each carbon atom. This type of potential is well suited for computer simulations of covalently bonded systems in both gas-phase and condensed-phase systems.

  12. Gas turbines

    Energy Technology Data Exchange (ETDEWEB)

    Farahan, E.; Eudaly, J.P.

    1978-10-01

    This evaluation provides performance and cost data for commercially available simple- and regenerative-cycle gas turbines. Intercooled, reheat, and compound cycles are discussed from theoretical basis only, because actual units are not currently available, except on a special-order basis. Performance characteristics investigated include unit efficiency at full-load and off-design conditions, and at rated capacity. Costs are tabulated for both simple- and regenerative-cycle gas turbines. The output capacity of the gas turbines investigated ranges from 80 to 134,000 hp for simple units and from 12,000 to 50,000 hp for regenerative units.

  13. 17 CFR 229.1204 - (Item 1204) Oil and gas production, production prices and production costs.

    Science.gov (United States)

    2010-04-01

    ... price (including transfers) per unit of oil, gas and other products produced; and (2) The average... conversion to synthetic oil or gas, the product's production, transfer prices, and production costs should be disclosed separately from all other products. Instruction 4 to Item 1204: The transfer price of oil and...

  14. Research on Steam Condensation Heat Transfer Model in Presence of Non-condensable Gas at High Pressure%高压条件下含有非凝结性气体的水蒸气凝结传热模型研究

    Institute of Scientific and Technical Information of China (English)

    吴磊; 刘洋; 贾海军; 杨星团

    2016-01-01

    T he research on the steam condensation heat transfer in presence of non‐condensable gas at high pressure is vital in the safety of small reactors . Now the research of this physical problem mostly focuses on the low pressure condition ,and the research on the high pressure condition is quite immature .The steam condensation heat transfer model in presence of non‐condensable gas at high pressure w as established in this paper .Instead of the ideal gas assumption ,the real gas state equation was adopted to determine the relationship between the concentration gradient and partial pressure gradient in the diffusion equation . The model results coincide well with the existing experiment data , and it is indicated that this approach can be used for the thermo‐hydraulic analysis in the gas‐steam pressurizer ,compact containment and other nuclear safety related equipments .%研究高压条件下含有非凝结性气体的水蒸气凝结传热过程对于小型堆的安全非常重要。当前对这一物理过程的研究集中于压力较低的工况,高压条件下的研究尚不成熟。本文建立了一种适用于高压条件下含有非凝结性气体的水蒸气自然对流凝结传热理论模型,使用真实气体状态方程求解扩散方程中摩尔浓度梯度和分压梯度之间的关系,取代了前人方法中的理想气体假设。计算结果与已有的实验数据吻合较好,证明本方法可用于小型堆紧凑型安全壳和汽‐气稳压器等安全级设备的热工分析。

  15. Gas gangrene

    Science.gov (United States)

    ... also can be caused by group A streptococcus, Staphylococcus aureus, and Vibrio vulnificus . Clostridium is found nearly everywhere. As the bacteria grow inside the body, it makes gas and harmful substances (toxins) that can damage body tissues, cells, and blood ...

  16. Technology transfer by multinationals

    OpenAIRE

    2003-01-01

    The paper analyses the issue of technology transfer by multinational corporations. The following questions are explored: (a) world market of technologies, the role of MNCs (b) Choice of the technology transfer mode, Dunning's OLI-theory as a factor of the choice of the mode of transfer (c) measurement and profitability of technology transfer (d) transfer of technology through partnerships, JVs, alliances and through M&As (e) aspects of technology transfer by services multinationals. Paper uti...

  17. Catalytic hot gas cleaning of gasification gas

    Energy Technology Data Exchange (ETDEWEB)

    Simell, P. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1997-12-31

    {sub 2}O and gasification gas. Operation conditions free of external or internal mass transfer limitations were used. Apparent first order kinetic parameters were determined for all the studied gas mixtures. In addition, for the CO{sub 2} reaction, a mechanistic model of Langmuir-Hinshelwood type was derived and tested. The best mode was based on benzene single site adsorption as the rate determining step and non-dissociable adsorption of CO{sub 2}. To be active in gasification gas carbonate rocks have to be in a calcined state. When the catalyst was carbonated and water was present, the activity of the catalysts was lost almost completely. This decline of activity closely followed the equilibrium decomposition pressure and temperature of CaCO{sub 3}. (orig.) 56 refs.

  18. Study of heat transfer in CI engine using heat transfer correlation based on intake jet velocity

    Energy Technology Data Exchange (ETDEWEB)

    Sharief, A. [Sri Siddharhta Inst. of Technology, Tumkur, Karnataka (India); Samaga, B.S.; Shrinivas Rao, B.R. [Nitte Mahalinga Adyantaya Institute of Technology, Karkala, Karnataka (India); JAntonyc, A. [Sahyadri Inst. of Technology, Mangalore, Karnataka (India)

    2009-07-01

    A reliable heat transfer formulation is needed to simulate reciprocating combustion engines. In order to reduce heat loss and improve thermal efficiency, it is necessary to calculate the rate of heat transfer from the working fluid to the combustion chamber walls. The thermal stresses in the engine components must also be determined. In this study, the author calculated heat transfer coefficient in a diesel engine using a heat transfer correlation based on intake jet velocity instead of mean piston speed. Experiments were conducted in a diesel engine with natural aspiration of hot air at 150 to 300 degrees C. Peak temperature was 1100 degrees C at various loads. The convective heat transfer coefficient and radiative heat transfer coefficient component was also determined separately at various loads. This model based on intake jet velocity instead of mean piston speed was found to be more realistic when considering the influence of gas velocities on the thermal boundary layer thickness. 11 refs., 12 figs.

  19. Comment on "Similarity analysis in magnetohydrodynamics: effects of Hall and ion-slip currents on free convection flow and mass transfer of a gas past a semi-infinite vertical plate," A.A. Megahed, S.R. Komy, A.A. Afify

    CERN Document Server

    Pantokratoras, Asterios

    2007-01-01

    Comment on Similarity analysis in magnetohydrodynamics:effects of Hall and ion-slip currents on free convection flow and mass transfer of a gas past a semi-infinite vertical plate, A.A. Megahed, S.R. Komy, A.A. Afify [Acta Mechanica 151, 185-194 (2001)] In the above paper is investigated the boundary layer flow of an electrically conducting fluid over a vertical, stationary plate placed in a calm fluid. The effects of Hall and ion-slip currents are taken into account. The boundary layer equations are transformed into ordinary ones using a scaling group of transformations and subsequently are solved numerically. However, there are two fundamental errors in the above paper which are presented below.

  20. 78 FR 37213 - Southern Union Company, d/b/a Missouri Gas Energy; Laclede Gas Company; Notice of Application

    Science.gov (United States)

    2013-06-20

    ... jurisdiction certificate for the purpose of transporting natural gas in the same manner as MGE Southern Union...: (1) Requesting authorization for MGE Southern Union pursuant to section 7(b) of the Natural Gas Act (NGA) to abandon by transfer to Laclede its limited jurisdiction certificate to transport gas on a...

  1. Research into the transmission of natural gas by gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Gadonneix, P.

    1998-12-31

    This paper is the press release of the talk given at the `Gaz de France scientific meeting with the press` by P. Gadonneix, chairman of Gaz de France company, on October 7, 1998. The aim of this talk concerns the new French and European supply link for bringing natural gas from the Norwegian North Sea fields. This new supply link is the first direct link between Norway and France and the NorFra gas pipeline which brings natural gas from the North Sea to France is the longest offshore pipeline in the world. The `Artere des Hauts de France` pipeline (the largest diameter gas pipeline ever laid in France) is devoted to the transfer of natural gas from Dunkerque to the Gournay-sur-Aronde underground storage site. This paper describes successively: the French European gas supply hub, the NorFra project, the Artere des Hauts de France pipeline, the network performance research, the safety and quality guaranties, the reduction of overland natural gas transmission costs (improvement of pipe-laying techniques and optimization of line route and welding operations), the specific techniques used for road and river crossing (micro-tunnel digging, river-crossing ditches) and for anchoring (buoyancy compensation). Finally, the environmental impact of the laying operations is briefly described. (J.S.)

  2. Geo energy research and development: technology transfer update

    Energy Technology Data Exchange (ETDEWEB)

    Traeger, R.K.; Dugan, V.L.

    1983-01-01

    Sandia Geo Energy Programs in geothermal, coal, oil and gas, and synfuel technologies have been effective in transferring research concepts to applications in private industry. This report updates the previous summary (SAND82-0211, March 1982) to include recent technology transfers and to reflect recent changes in philosophy on technology transfer. Over 40 items transferred to industry have been identified in the areas of Hardware, Risk Removal and Understanding. Successful transfer is due largely to personal interactions between Sandia engineers and the technical staffs of private industry.

  3. Targeted Technology Transfer to US Independents

    Energy Technology Data Exchange (ETDEWEB)

    Donald F. Duttlinger; E. Lance Cole

    2006-09-29

    The Petroleum Technology Transfer Council (PTTC) was established by domestic crude oil and natural gas producers in 1994 as a national not-for-profit organization to address the increasingly urgent need to improve the technology-transfer process in the U.S. upstream petroleum industry. Coordinated from a Headquarters (HQ) office in Houston, PTTC maintains an active grassroots program executed by 10 Regional Lead Organizations (RLOs) and two satellite offices (Figure 1). Regional Directors interact with domestic oil and gas producers through technology workshops, resource centers, websites, newsletters, technical publications and cooperative outreach efforts. HQ facilitates inter-regional technology transfer and implements a comprehensive communications program. Active volunteers on the National Board and in Producer Advisory Groups (PAGs) in each of the 10 regions focus effort in areas that will create the most impact for domestic producers. Focused effort by dedicated individuals across the country has enabled PTTC to achieve the milestones outlined in Appendix A.

  4. Tolley's industrial and commercial gas installation practice

    CERN Document Server

    Hazlehurst, John

    2010-01-01

    This is the third of three essential reference volumes for those concerned with the installation and servicing of domestic and industrial gas equipment. This volume explains the basic principles underlying the practical and theoretical aspects of installing and servicing gas appliances and associated equipment, from the basics of combustion, to burners, pressure and flow, transfer of heat, controls, as well as materials and processes, electrical aspects, and metering and measuring devices. Covering both Natural Gas and Liquefied Petroleum Gas, the many illustrations and worked examples include

  5. Transfer Readiness Pilot Study.

    Science.gov (United States)

    Scott-Skillman, Thelma; And Others

    The California Community Colleges (CCC) has implemented a prototype model for determining student transfer readiness as a primary means of assessing community college transfer effectiveness. This report provides definitions of transfer readiness and guidelines for colleges participating in the CCC transfer readiness study. First, a memorandum from…

  6. The porosity in a fluidized bed heat transfer model

    NARCIS (Netherlands)

    Visser, G.; Valk, M.

    1993-01-01

    A mathematical model of heat transfer between a fluidized bed and an immersed surface and a model of gas flow and porosity, both recently published, were combined and further modified in the area of low velocities where the particle convective component of heat transfer is low or neglectable. Experi

  7. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  8. Mass transfer in rolling rotary kilns : a novel approach

    NARCIS (Netherlands)

    Heydenrych, M.D.; Greeff, P.; Heesink, A. Bert M.; Versteeg, G.F.

    2002-01-01

    A novel approach to modeling mass transfer in rotary kilns or rotating cylinders is explored. The movement of gas in the interparticle voids in the bed of the kiln is considered, where particles move concentrically with the geometry of the kiln and gas is entrained by these particles. The approach c

  9. Gas hydrates

    Digital Repository Service at National Institute of Oceanography (India)

    Ramprasad, T.

    , not all of them are white like snow. Some hydrates from the deep Gulf of Mexico are richly colored in shades of yellow, orange, or even red. The ice-like masses are beautiful, and contrast with the dull gray of deep sea muds. Hydrates from the Blake... volcanoes and associated gas hydrates: Marine Geology, v. 167, p. 29-42. Milkov, A.V. and R. Sassen, 2001a, Estimate of gas hydrate resource, northwestern Gulf of Mexico continental slope: Marine Geology, v. 179, pp. 71-83. Milkov, A.V., Sassen, R...

  10. 管壳式换热器壳侧气液两相流动和传热的数值模拟研究%Study on Numerical Simulation of Gas-liquid Two-phase Flow and Heat Transfer of Shell Side in a Shell and Tube Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    吕金丽; 戈锐; 李想; 张玉宝

    2012-01-01

    采用数值模拟方法,使用FLUENT对管壳式换热器壳侧的两相流动及相变传热进行了模拟计算.根据壳侧流体流动特点,选定合适的湍流模型、两相流模型为混合物模型,并根据汽水转化公式编写了自定义函数UDF来描述相变过程质和量的传递.对管壳式换热器壳侧的流体介质换热发生相变并产生气液两相流动进行了三维的数值模拟研究.得到了管壳式换热器壳程的速度场、温度场、压力场及气液各相的分布情况,对壳侧气液两相流动及相变换热进行了分析.对具有相变情况下的管壳式换热器的结构设计起到参考指导作用.%Numerical simulation methods are adopted in this paper. With the FLUENT software,the paper stimulates the two-phase flow and phase change and heat transfer. A turbulence model and a two-phase flow model are selected in this paper. Based on the characteristics of shell-side in the shell and tube heat exchangers, the paper writes User-defined Function (UDF) to describe the phase transition of quality and quantity through the use of the conversion formula. Flow media of shell and tube heat exchanger shell-side heat transfer occurring phase change and gas-liquid two-phase flow are studied by 3D numerical-simulation, obtaining velocity field, temperature field, pressure field and gas-liquid distribution of shell and tube heat exchanger shell side. The two-phase flow and phase change and heat transfer of shell-side in the shell and tube heat exchangers are analyzed. These will be provided some valuable references for the improvement of tube condenser structure design.

  11. Thermal radiation heat transfer

    CERN Document Server

    Howell, John R; Siegel, Robert

    2016-01-01

    Further expanding on the changes made to the fifth edition, Thermal Radiation Heat Transfer, 6th Edition continues to highlight the relevance of thermal radiative transfer and focus on concepts that develop the radiative transfer equation (RTE). The book explains the fundamentals of radiative transfer, introduces the energy and radiative transfer equations, covers a variety of approaches used to gauge radiative heat exchange between different surfaces and structures, and provides solution techniques for solving the RTE.

  12. Radiation and gas conduction heat transport across a helium dewer multilayer insulation system

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.A. [Lawrence Berkeley Lab., CA (United States)

    1995-02-01

    This report describes a method for calculating mixed heat transfer through the multilayer insulation used to insulated a 4K liquid helium cryostat. The method described permits one to estimate the insulation potential for a multilayer insulation system from first principles. The heat transfer regimes included are: radiation, conduction by free molecule gas conduction, and conduction through continuum gas conduction. Heat transfer in the transition region between the two gas conduction regimes is also included.

  13. Design of gas-inducing reactors

    Energy Technology Data Exchange (ETDEWEB)

    Patwardhan, A.W.; Joshi, J.B. [Univ. of Mumbai (India). Dept. of Chemical Technology

    1999-01-01

    A gas-inducing impeller enables efficient recycling of gas from the headspace into the liquid. Historically, these impellers were used for the first time in froth flotation machines. The various designs of gas-inducing impellers (including those used in froth flotation) could be classified into three categories, depending on the flow pattern coming into and leaving the impeller zone. Correlations for the power consumption, fractional gas holdup, mass-transfer coefficient, and so forth are also available in the literature, although these studies are not comprehensive. A process design algorithm has been presented for the design of gas-inducing impellers. The algorithm consists of the determination of the rate-controlling step, selection of geometry and the operating conditions, and an economic analysis to choose the optimum design. Guidelines have been given about the desired geometry of gas-inducing impellers for achieving different design objectives such as heat transfer, mass transfer, mixing, solid suspension, froth flotation, and so forth. It has been shown that the use of a gas-inducing impeller in a conventional stirred vessel can lead to a substantial increase in the productivity. It has been shown that the optimum geometry may not correspond to the maintenance of equal power consumption per unit volume, or equal tip speed on scale-up. Suggestions have been made for future work in this area.

  14. Gas sensor

    Science.gov (United States)

    Schmid, Andreas K.; Mascaraque, Arantzazu; Santos, Benito; de la Figuera, Juan

    2014-09-09

    A gas sensor is described which incorporates a sensor stack comprising a first film layer of a ferromagnetic material, a spacer layer, and a second film layer of the ferromagnetic material. The first film layer is fabricated so that it exhibits a dependence of its magnetic anisotropy direction on the presence of a gas, That is, the orientation of the easy axis of magnetization will flip from out-of-plane to in-plane when the gas to be detected is present in sufficient concentration. By monitoring the change in resistance of the sensor stack when the orientation of the first layer's magnetization changes, and correlating that change with temperature one can determine both the identity and relative concentration of the detected gas. In one embodiment the stack sensor comprises a top ferromagnetic layer two mono layers thick of cobalt deposited upon a spacer layer of ruthenium, which in turn has a second layer of cobalt disposed on its other side, this second cobalt layer in contact with a programmable heater chip.

  15. Elaboration of the international transfer mechanism of reduction in greenhouse gas emissions on the basis of the Russian federal law {sup A}bout agreements of products sharing'

    Energy Technology Data Exchange (ETDEWEB)

    Toivonen, N.R.; Koulikovskaya, L. [Petrozavodsk State University (Russian Federation)

    2001-07-01

    Suggestions for a comprehensive legal framework for the implementation in Russia of the flexibility mechanisms established under the Kyoto Protocol (i.e. joint implementation; clean development mechanism; international emissions trading) are proposed. It is suggested that the legal framework be established using the principles embodied in the existing Russian federal law, 'About agreements of product sharing' adopted in 1995. As a basic requirement, it is suggested that the new federal law must include the fundamental elements required to create possibilities for the Russian Federation to participate in the process of certified emission reductions (CER) transfer, emissions reduction unit (ERU) negotiation, and adjusted amount units (AAU) trading within the framework of the Kyoto Protocol implementation. The new law must also embody the basic procedures required to enter into agreements at the international, inter-regional and inter-sectoral levels. Failure to develop the legislative support and the legal framework to facilitate valid Russian participation in the implementation of the Kyoto Protocol will prevent many valuable initiatives and projects from being realized.

  16. Mixing and mass transfer in a pilot scale U-loop bioreactor

    DEFF Research Database (Denmark)

    Petersen, Leander Adrian Haaning; Villadsen, John; Jørgensen, Sten Bay;

    2017-01-01

    A system capable of handling a large volumetric gas fraction while providing a high gas to liquid mass transfer is a necessity if the metanotrophic bacterium Methylococcus capsulatus is to be used in single cell protein (SCP) production. In this study mixing time and mass transfer coefficients we...

  17. Mass transfer in wetted-wall columns: correlations at high Reynolds numbers

    DEFF Research Database (Denmark)

    Nielsen, Christian H.E.; Kiil, Søren; Thomsen, Henrik W.;

    1998-01-01

    The rate of gas-and liquid-phase mass transport in a pilot-scale wetted-wall column with an inner diameter of 3.26 cm and a length of 5 m was investigated. Empirical correlations for the physical liquid-phase mass transfer coefficient (k(L)(O)) and the gas-phase mass transfer coefficient (k...

  18. Natural Gas Transport

    OpenAIRE

    Tomás Correa; Nelson Osorio

    2009-01-01

    This paper reviews the present and future on natural gas transportation options, from oil and gas fields to markets, including liquefied natural gas, gas pipeline, compressed natural gas, natural gas hydrates, and gas to liquids and the perspectives of using them in Colombia, since this is the main fuel alternative to supply the world in at least the next 50 years.

  19. Natural Gas Transport

    Directory of Open Access Journals (Sweden)

    Tomás Correa

    2009-06-01

    Full Text Available This paper reviews the present and future on natural gas transportation options, from oil and gas fields to markets, including liquefied natural gas, gas pipeline, compressed natural gas, natural gas hydrates, and gas to liquids and the perspectives of using them in Colombia, since this is the main fuel alternative to supply the world in at least the next 50 years.

  20. Transfer Characteristics in Mechanically Stirred Airlift Loop Reactors with or without Static Mixers

    Institute of Scientific and Technical Information of China (English)

    吕效平; 王延儒; 时钧

    2000-01-01

    The mechanically stirred internal loop airlift reactors equipped with or without static mixers are devised for intensification of gas-liquid mass transfer rate. The influences of superficial gas velocity, agitation or static mixers on gas hold-up, mixing time, liquid circulating velocity and volumetric mass transfer coefficient have been investigated with tap water and carboxymethyl cellulose (CMC) aqueous solution. The experimental results indicate that mechanical agitation is more efficacious than static mixer in highly viscous media for improving mass transfer in airlift reactors. The empirical correlation of volumetric mass transfer coefficient with apparent viscosity, and energy consumption for mechanical agitation and aeration is developed.

  1. Wood gas; Holz gibt Gas

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, Claudia

    2011-06-17

    Sixty years ago, wood gas was even used as a car fuel. Today, this ancient technology is experiencing a renaissance. Small cogeneration plants with wood gasifiers are ideal for renewable and decentral power supply concepts for tomorrow. Until then, there is much pioneering work to do until plants will be ready for serial production.

  2. Determination of Vinyl Chloride at ug/l. Level in Water by Gas Chromatography

    Science.gov (United States)

    Bellar, Thomas A.; And Others

    1976-01-01

    A quantitative method for the determination of vinyl chloride in water is presented. Vinyl chloride is transfered to the gas phase by bubbling inert gas through the water. After concentration on silica gel or Carbosieve-B, determination is by gas chromatography. Confirmation of vinyl chloride is by gas chromatography-mass spectrometry. (Author/BT)

  3. Gas-Phase Covalent And Non-Covalent Ion/ion Chemistry Of Biological Macromolecules

    OpenAIRE

    Stutzman, John Robert

    2013-01-01

    Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry. The work de...

  4. Study on Commercial Application of FP-DSN Sulfur Transfer Additive in FCC Unit

    Institute of Scientific and Technical Information of China (English)

    Gao Siming; Han Rongxian; Chen Desheng

    2009-01-01

    The FCC unit with addition of various inventories of the FP-DSN type sulfur transfer additive was tested in a commercial scale. The effect of the sulfur transfer additive was analyzed by investigating the indicators related with the regenerator flue gas composition, the dry gas composition before desulfurization, the LPG composition before desulfurization, the acid gas, and the yield of gasoline and diesel. The test results indicated that the sulfur was trans-ferred fi'om the feed stream into the dry gas, LPG and acid gas, and the sulfur transfer effect was obvious only when the inventory of sulfur transfer additive exceeded over 2.0% of total FCC catalyst inventory.

  5. Local Heat and Mass Transfer for Gas—Solid Two Phase Flow in CFB

    Institute of Scientific and Technical Information of China (English)

    FengLu; Ming-HengShi

    1994-01-01

    An experimental investigation on the flow characteristics and the local heat and mass transfer between coarse wet particles and hot gas in the circulaing fluidized bed(CFB) has been performed.A twothermocouple contrast method was developed to measure the local gas and solid temperature along the height of the bed.The influences of air superficial velocity,solid rate and initial moisture content on the local heat and mass transfer between gas and sloid were examined.The correlations of heat and mass transfer coefficients between gas and coarse wet particles in CFB were obtained.

  6. 高温气冷堆球床等效导热系数实验研究进展%Progress in Pebble Bed Heat Transfer Test Facility of High Temperature Gas-cooled Reactor

    Institute of Scientific and Technical Information of China (English)

    任成; 杨星团; 李聪新; 孙艳飞

    2013-01-01

    Pebble bed effective thermal conductivity of the reactor core is a vital parameter which directly affects the maximum temperature of fuel and the temperature distribution of reactor core in high temperature gas-cooled reactor and plays a dominant role in afterheat removal. The experimental research of pebble bed effective thermal conductivity is helpful for improving the reactor analytical program, increasing the power of single reactor and the safe analysis of projects. The experiments and results of pebble bed effective thermal conductivity measurement at home and abroad are reviewed. The develop direction is also discussed.%堆芯球床等效导热系数是直接影响高温气冷堆燃料最高温度和堆芯温度分布的关键参数;在余热导出过程中起主导作用.开展球床等效导热系数的实验研究对于反应堆分析程序的完善、研究提高高温气冷堆单堆功率的可能性、以及工程的安全分析具有重要的意义.综述了国内外球床等效导热系数测量的研究现状,给出了清华大学HTR-PM三维堆芯球床等效导热系数测量实验最新成果,总结了各国实验的研究手段,对研究方向进行了讨论.

  7. ASSEMBLY TRANSFER SYSTEM DESCRIPTION DOCUMENT

    Energy Technology Data Exchange (ETDEWEB)

    B. Gorpani

    2000-06-26

    The Assembly Transfer System (ATS) receives, cools, and opens rail and truck transportation casks from the Carrier/Cask Handling System (CCHS). The system unloads transportation casks consisting of bare Spent Nuclear Fuel (SNF) assemblies, single element canisters, and Dual Purpose Canisters (DPCs). For casks containing DPCs, the system opens the DPCs and unloads the SNF. The system stages the assemblies, transfer assemblies to and from fuel-blending inventory pools, loads them into Disposal Containers (DCs), temporarily seals and inerts the DC, decontaminates the DC and transfers it to the Disposal Container Handling System. The system also prepares empty casks and DPCs for off-site shipment. Two identical Assembly Transfer System lines are provided in the Waste Handling Building (WHB). Each line operates independently to handle the waste transfer throughput and to support maintenance operations. Each system line primarily consists of wet and dry handling areas. The wet handling area includes a cask transport system, cask and DPC preparation system, and a wet assembly handling system. The basket transport system forms the transition between the wet and dry handling areas. The dry handling area includes the dry assembly handling system, assembly drying system, DC preparation system, and DC transport system. Both the wet and dry handling areas are controlled by the control and tracking system. The system operating sequence begins with moving transportation casks to the cask preparation area. The cask preparation operations consist of cask cavity gas sampling, cask venting, cask cool-down, outer lid removal, and inner shield plug lifting fixture attachment. Casks containing bare SNF (no DPC) are filled with water and placed in the cask unloading pool. The inner shield plugs are removed underwater. For casks containing a DPC, the cask lid(s) is removed, and the DPC is penetrated, sampled, vented, and cooled. A DPC lifting fixture is attached and the cask is placed

  8. Volcanic gas

    Science.gov (United States)

    McGee, Kenneth A.; Gerlach, Terrance M.

    1995-01-01

    In Roman mythology, Vulcan, the god of fire, was said to have made tools and weapons for the other gods in his workshop at Olympus. Throughout history, volcanoes have frequently been identified with Vulcan and other mythological figures. Scientists now know that the “smoke" from volcanoes, once attributed by poets to be from Vulcan’s forge, is actually volcanic gas naturally released from both active and many inactive volcanoes. The molten rock, or magma, that lies beneath volcanoes and fuels eruptions, contains abundant gases that are released to the surface before, during, and after eruptions. These gases range from relatively benign low-temperature steam to thick hot clouds of choking sulfurous fume jetting from the earth. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other volcanic gases are hydrogen sulfide, hydrochloric acid, hydrogen, carbon monoxide, hydrofluoric acid, and other trace gases and volatile metals. The concentrations of these gas species can vary considerably from one volcano to the next.

  9. Radiative heat transfer in porous uranium dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, S.L. [Texas A and M Univ., College Station, TX (United States)

    1992-12-01

    Due to low thermal conductivity and high emissivity of UO{sub 2}, it has been suggested that radiative heat transfer may play a significant role in heat transfer through pores of UO{sub 2} fuel. This possibility was computationally investigated and contribution of radiative heat transfer within pores to overall heat transport in porous UO{sub 2} quantified. A repeating unit cell was developed to model approximately a porous UO{sub 2} fuel system, and the heat transfer through unit cells representing a wide variety of fuel conditions was calculated using a finite element computer program. Conduction through solid fuel matrix as wekk as pore gas, and radiative exchange at pore surface was incorporated. A variety of pore compositions were investigated: porosity, pore size, shape and orientation, temperature, and temperature gradient. Calculations were made in which pore surface radiation was both modeled and neglected. The difference between yielding the integral contribution of radiative heat transfer mechanism to overall heat transport. Results indicate that radiative component of heat transfer within pores is small for conditions representative of light water reactor fuel, typically less than 1% of total heat transport. It is much larger, however, for conditions present in liquid metal fast breeder reactor fuel; during restructuring of this fuel type early in life, the radiative heat transfer mode was shown to contribute as much as 10-20% of total heat transport in hottest regions of fuel.

  10. Convective heat transfer

    CERN Document Server

    Kakac, Sadik; Pramuanjaroenkij, Anchasa

    2014-01-01

    Intended for readers who have taken a basic heat transfer course and have a basic knowledge of thermodynamics, heat transfer, fluid mechanics, and differential equations, Convective Heat Transfer, Third Edition provides an overview of phenomenological convective heat transfer. This book combines applications of engineering with the basic concepts of convection. It offers a clear and balanced presentation of essential topics using both traditional and numerical methods. The text addresses emerging science and technology matters, and highlights biomedical applications and energy technologies. What’s New in the Third Edition: Includes updated chapters and two new chapters on heat transfer in microchannels and heat transfer with nanofluids Expands problem sets and introduces new correlations and solved examples Provides more coverage of numerical/computer methods The third edition details the new research areas of heat transfer in microchannels and the enhancement of convective heat transfer with nanofluids....

  11. Introduction to heat transfer

    CERN Document Server

    SUNDÉN, B

    2012-01-01

    Presenting the basic mechanisms for transfer of heat, Introduction to Heat Transfer gives a deeper and more comprehensive view than existing titles on the subject. Derivation and presentation of analytical and empirical methods are provided for calculation of heat transfer rates and temperature fields as well as pressure drop. The book covers thermal conduction, forced and natural laminar and turbulent convective heat transfer, thermal radiation including participating media, condensation, evaporation and heat exchangers.

  12. Bed-to-wall heat transfer in a downer reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lehner, P.; Wirth, K-E. [Erlangen-Nuremberg Univ., Lehrstuhl Mechanische Verfahrenstechnik, Erlangen (Germany)

    1999-04-01

    The effects of superficial gas velocity, solid circulating rate, suspension density and particle sizes on the bed-to-wall heat transfer coefficient have been determined in a downer reactor 3.5 m high , with an internal diameter of 0.1 m. Results showed an increase in the bed-to-wall heat transfer coefficient with increasing suspension density. The heat transfer coefficient by gas convection was found to play a significant role, especially at lower solid circulation rates or suspension densities and larger particle sizes. It was determined that at a given particle suspension density in the downer reactor, the heat transfer coefficient increase with decreasing particle size. A model was proposed to determine the bed-to-wall heat transfer coefficient in a downer reactor. 24 refs., 1 tab., 8 figs.

  13. Transfer of gaming

    NARCIS (Netherlands)

    Korteling, J.E.

    2012-01-01

    An overview is provided of the activities and results op GATE WP 4.4 entiteld Transfer of Gaming (ToG). This work package has produced the principles and methodologies concerning optimalization and measurement of transfer of training in serious gaming. In addition, true transfer of job-specific comp

  14. Jet flow pattern and its effects on mass transfer area and gas phase pressure drop in a water-sparged aerocyclone%水力喷射空气旋流器中射流流型及其对传质面积和气相压降的影响

    Institute of Scientific and Technical Information of China (English)

    程治良; 全学军; 晏云鹏; 代黎

    2014-01-01

    Water-sparged aerocyclone (WSA) is high efficiency gas-liquid mass transfer equipment, which takes the advantage of coupling effect of gas cyclone and liquid jet fields. In order to investigate the mechanism of jet-cyclone system of WSA and improve its mass transfer performance, jet flow pattern and its transformation was investigated by direct observation. Effective gas-liquid interfacial area per unit volume (a) of the WSA was also determined by chemical reaction method with CO2-NaOH solution system. The results show that jet flow pattern is mainly affected by jet velocity and air inlet velocity. There exists five jet flow patterns in the WSA, i.e., steady state jet, deformed spiral jet, broken spiral jet, atomized spiral jet and total atomized spiral jet at jet velocity less than 4.42 m·s-1. At the jet velocity higher than 6.19 m·s-1 there exists only three jet flow patterns, i.e. deformed spiral jet, broken spiral jet and atomized spiral jet. The value of a is related to jet flow pattern, higher in atomized spiral jet than in other jets, and increases with liquid jet velocity because of the intense gas-liquid interaction in the WSA.%为了进一步提高水力喷射空气旋流器(WSA)的传质效率以及认识射旋流体系的气液传质机理,对 WSA中的射流流型进行了系统的观察研究,绘制出了不同进口气速下射流流型图。以CO2-NaOH化学吸收体系测定了相应射流流型下的有效比相界面积 a。结果表明,在低射流流速(≤4.42 m·s-1)下,液相射流随着进口气速增大,主要存在稳态射流、变形旋线射流、破碎旋线射流、雾化旋线射流、贴壁雾化旋线射流5种流型;在高射流流速(≥6.19 m·s-1)下,射流主要出现稳态射流、破碎旋线射流以及雾化旋线射流3种流型。a值与流型有关,雾化旋线射流下的a值大于其他流型下的对应值。低流速下的贴壁雾化,不利于气液两相充分接触,对应a值

  15. Characteristics of three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids.

    Science.gov (United States)

    Wen, Jianping; Jia, Xiaoqiang; Cheng, Xianrui; Yang, Peng

    2005-05-01

    Hydrodynamic and gas-liquid mass transfer characteristics, such as liquid velocity, gas holdup, solid holdup and gas-liquid volumetric mass transfer coefficient, in the riser and downcomer of the gas-liquid-solid three-phase internal loop airlift bioreactors with complete gas recirculation for non-Newtonian fluids, were investigated. A mathematical model for the description of flow behavior and gas-liquid mass transfer of these bioreactors was developed. The predicted results of this model agreed well with the experimental data.

  16. Transfer function combinations

    KAUST Repository

    Zhou, Liang

    2012-10-01

    Direct volume rendering has been an active area of research for over two decades. Transfer function design remains a difficult task since current methods, such as traditional 1D and 2D transfer functions, are not always effective for all data sets. Various 1D or 2D transfer function spaces have been proposed to improve classification exploiting different aspects, such as using the gradient magnitude for boundary location and statistical, occlusion, or size metrics. In this paper, we present a novel transfer function method which can provide more specificity for data classification by combining different transfer function spaces. In this work, a 2D transfer function can be combined with 1D transfer functions which improve the classification. Specifically, we use the traditional 2D scalar/gradient magnitude, 2D statistical, and 2D occlusion spectrum transfer functions and combine these with occlusion and/or size-based transfer functions to provide better specificity. We demonstrate the usefulness of the new method by comparing to the following previous techniques: 2D gradient magnitude, 2D occlusion spectrum, 2D statistical transfer functions and 2D size based transfer functions. © 2012 Elsevier Ltd.

  17. Making benefit transfers work

    DEFF Research Database (Denmark)

    Bateman, I.J.; Brouwer, R.; Ferrini, S.

    We develop and test guidance principles for benefits transfers. These argue that when transferring across relatively similar sites, simple mean value transfers are to be preferred but that when sites are relatively dissimilar then value function transfers will yield lower errors. The paper also...... provides guidance on the appropriate specification of transferable value functions arguing that these should be developed from theoretical rather than ad-hoc statistical principles. These principles are tested via a common format valuation study of water quality improvements across five countries. Results...... support our various hypotheses providing a set of principles for future transfer studies. The application also considers new ways of incorporating distance decay, substitution and framing effects within transfers and presents a novel water quality ladder....

  18. Making benefit transfers work

    DEFF Research Database (Denmark)

    Bateman, I. J.; Brouwer, R.; Ferrini, S.

    2011-01-01

    We develop and test guidance principles for benefits transfers. These argue that when transferring across relatively similar sites, simple mean value transfers are to be preferred but that when sites are relatively dissimilar then value function transfers will yield lower errors. The paper also...... provides guidance on the appropriate specification of transferable value functions arguing that these should be developed from theoretical rather than ad-hoc statistical principles. These principles are tested via a common format valuation study of water quality improvements across five countries. Results...... support our various hypotheses providing a set of principles for future transfer studies. The application also considers new ways of incorporating distance decay, substitution and framing effects within transfers and presents a novel water quality ladder....

  19. Natural gas conversion process

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The experimental apparatus was dismantled and transferred to a laboratory space provided by Lawrence Berkeley Laboratory (LBL) which is already equipped with a high-ventilation fume hood. This will enable us to make tests at higher gas flow rates in a safe environment. Three papers presented at the ACS meeting in San Francisco (Symposium on Natural Gas Upgrading II) April 5--10, 1992 show that the goal of direct catalytic conversion of Methane into heavier Hydrocarbons in a reducing atmosphere is actively pursued in three other different laboratories. There are similarities in their general concept with our own approach, but the temperature range of the experiments reported in these recent papers is much lower and this leads to uneconomic conversion rates. This illustrates the advantages of Methane activation by a Hydrogen plasma to reach commercial conversion rates. A preliminary process flow diagram was established for the Integrated Process, which was outlined in the previous Quarterly Report. The flow diagram also includes all the required auxiliary facilities for product separation and recycle of the unconverted feed as well as for the preparation and compression of the Syngas by-product.

  20. 急冷废热锅炉进口分配器内分布管椭圆度对气体流动与分布的影响%Optimization and investigation of flow for circular and elliptic gas distributor tubes in transfer line exchanger

    Institute of Scientific and Technical Information of China (English)

    郭兆阳; 王元华; 徐宏; 史永红; 郭超; 杨胜

    2012-01-01

    For improving the performance of the four-inlet bathtub-type transfer line exchanger (TLE) used in a 10000 t yearly capacity cracking furnace, the characteristics of flow field in the entrance of TLE was investigated with CFD method. The effects of ellipse eccentricity of the cross-section of the distributor tubes on the low velocity region, residence time, vorticity, rate of turbulent dissipation and gas maldistribution were investigated. The results indicate that higher ellipse eccentricity reduces the low velocity region, residence time, vorticity, rate of turbulent dissipation in the entrance of the TLE, but increases the maldistribution. A dimensionless performance index taking account of vorticity, turbulent dissipation rate and gas maldistribution was employed to compare and evaluate the overall performance in different ellipse eccentricity of distributor tube. The result shows that the optimal ellipse eccentricity of gas distributor tubes is between 1. 12 and 1. 2.%针对10万吨/年大型乙烯裂解炉用四进口“浴缸式”急冷废热锅炉现存问题,采用稳态与瞬态CFD数值计算方法研究了急冷废热锅炉进口分配器内的流动状况.比较了圆形截面和椭圆形截面分布管对流动的影响,分析了不同分布管截面椭圆度时废热锅炉换热管内的气体分配不均匀性及分配器内的低速区、停留时间、涡量和湍流耗散率.采用综合考虑涡量、湍流耗散率和气体分配不均匀性的量纲1化综合性能指标比较各结构的综合性能,结果表明当分布管椭圆度e在1.12~1.2之间时气体流动状况较佳.

  1. Advanced control for photoautotrophic growth and CO2-utilization efficiency using a membrane carbonation photobioreactor (MCPBR).

    Science.gov (United States)

    Kim, Hyun Woo; Marcus, Andrew K; Shin, Jeong Hoon; Rittmann, Bruce E

    2011-06-01

    A membrane carbonation (MC) module uses bubbleless gas-transfer membranes to supply inorganic carbon (C(i)) for photoautotrophic cyanobacterial growth in a photobioreactor (PBR); this creates the novel MCPBR system, which allows precise control of the CO(2)-delivery rate and minimal loss of CO(2) to the atmosphere. Experiments controlled the supply rate of C(i) to the main PBR by regulating the recirculation rate (Q(R)) between the module of MC chamber and the main PBR. The experiments evaluated how Q(R) controls the CO(2) mass transport in MC chamber and how it connects with the biomass production rate, C(i) concentration, pH in the PBR, and CO(2)-utilization efficiency. The biomass production rate and C(i) concentration increased in response to the C(i) supply rate (controlled by Q(R)), but not in linear proportion. The biomass production rate increased less than C(i) due to increased light limitation. Except for the highest Q(R), when the higher C(i) concentration caused the pH to decrease, CO(2) loss to gas ventilation was negligible. The results demonstrate that this MCPBR offers independent control over the growth of photoautotrophic biomass, pH control, and minimal loss of CO(2) to the atmosphere.

  2. Formation rate of natural gas hydrate

    Energy Technology Data Exchange (ETDEWEB)

    Mork, Marit

    2002-07-01

    The rate of methane hydrate and natural gas hydrate formation was measured in a 9.5 litre stirred tank reactor of standard design. The experiments were performed to better understand the performance and scale-up of a reactor for continuous production of natural gas hydrates. The hydrate formation rate was measured at steady-state conditions at pressures between 70 and 90 bar and temperatures between 7 and 15 deg C. Between 44 and 56 % of the gas continuously supplied to the reactor was converted to hydrate. The experimental results show that the rate of hydrate formation is strongly influenced by gas injection rate and pressure. The effect of stirring rate is less significant and subcooling has no observable effect on the formation rate. Hydrate crystal concentration and gas composition do not influence the hydrate formation rate. Observations of produced hydrate crystals indicate that the crystals are elongated, about 5 micron in diameter and 10 micron long. Analysis of the results shows that the rate of hydrate formation is dominated by gas-liquid mass transfer. A mass transfer model, the bubble-to-crystal model, was developed for the hydrate formation rate in a continuous stirred tank reactor, given in terms of concentration driving force and an overall mass transfer coefficient. The driving force is the difference between the gas concentration at the gas-liquid interface and at the hydrate crystal surface. These concentrations correspond to the solubility of gas in water at experimental temperature and pressure and the solubility of gas at hydrate equilibrium temperature and experimental pressure, respectively. The overall mass transfer coefficient is expressed in terms of superficial gas velocity and impeller power consumption, parameters commonly used in study of stirred tank reactors. Experiments and modeling show that the stirred tank reactor has a considerable potential for increased production capacity. However, at higher hydrate production rates the

  3. Sweet gas

    Science.gov (United States)

    Showstack, Randy

    When poisonous hydrogen sulfide contaminates a natural gas deposit, the drilling company usually caps the well and moves on to other areas that may contain larger reserves and offer stronger economic incentives. Chemical and biological methods exist to purify these wells, but most are complex and costly. However, a group of scientists now is developing what could be a cheaper, easier method to clean up and utilize this polluted natural gas.The technique—which involves growing “enrichment” cultures of bacteria that metabolize the hydrogen sulfide into harmless compounds—could be particularly useful to poor and energy-starved developing nations, says Norman Wainwright, a senior scientist at the Woods Hole Marine Biological Laboratory. “We're hoping the technique can be robust enough and inexpensive enough to be used in a developing country,” Wainwright says. Other scientists involved with the project are Porter Anderson, a University of Rochester professor emeritus associated with the lab and Ben Ebenhack, also of Rochester.

  4. 76 FR 44761 - Remittance Transfers

    Science.gov (United States)

    2011-07-27

    ... Electronic Fund Transfer Act (EFTA), as an example of money transfer instruments Federal credit unions (FCUs... receiving international and domestic electronic fund transfers'' after the words ``money orders'' from... checks, money orders, and other similar transfer instruments, including international and...

  5. Biological conversion of coal gas to methane

    Energy Technology Data Exchange (ETDEWEB)

    Barik, S.; Vega, J.L.; Clausen, E.C.; Gaddy, J.L.

    1988-08-01

    Biological conversion of low-Btu coal synthesis gas to higher Btu methane was demonstrated using both pure co-cultures and/or adapted-mixed anaerobic bacteria. Peptostreptococcus productus metabolized coal gas to mainly acetate and CO/sub 2/. The co-cultures containing methanogens converted these products to methane. In mixed culture studies, CH/sub 4/ and small amounts of acetate were produced. Reactor studies using stirred-tank and immobilized cell reactors exhibited excellent potential to convert CO, CO/sub 2/ and H/sub 2/ to methane at higher gas flow rates. Gas retention times ranging from 0.7 to 2 hours and high agitation were required for 90 percent CO conversion in these systems. This paper also illustrates the potential of biological methanation and demonstrates the need for good mass transfer in converting gas phase substrates. 21 refs., 1 fig., 7 tabs.

  6. [Evaluation of high-efficiency gas-liquid contactors for natural gas processing]. Semiannual technical progress report, October 1, 1992--March 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    1993-12-01

    The objective of this proposed program is to evaluate the potential of rotating gas-liquid contactors for natural gas processing by expanding the currently available database. This expansion will focus on application of this technology to environments representative of those typically encountered in natural gas processing plants. Operational and reliability concerns will be addressed while generating pertinent engineering data relating to the mass-transfer process. This report presents results on fluid dynamics and mass transfer coefficient studies.

  7. Oxygen transfer in a pressurized airlift bioreactor.

    Science.gov (United States)

    Campani, Gilson; Ribeiro, Marcelo Perencin Arruda; Horta, Antônio Carlos Luperni; Giordano, Roberto Campos; Badino, Alberto Colli; Zangirolami, Teresa Cristina

    2015-08-01

    Airlift bioreactors (ALBs) offer advantages over conventional systems, such as simplicity of construction, reduced risk of contamination, and efficient gas-liquid dispersion with low power consumption. ALBs are usually operated under atmospheric pressure. However, in bioprocesses with high oxygen demand, such as high cell density cultures, oxygen limitation may occur even when operating with high superficial gas velocity and air enriched with oxygen. One way of overcoming this drawback is to pressurize the reactor. In this configuration, it is important to assess the influence of bioreactor internal pressure on the gas hold-up, volumetric oxygen transfer coefficient (k(L)a), and volumetric oxygen transfer rate (OTR). Experiments were carried out in a concentric-tube airlift bioreactor with a 5 dm(3) working volume, equipped with a system for automatic monitoring and control of the pressure, temperature, and inlet gas flow rate. The results showed that, in disagreement with previous published results for bubble column and external loop airlift reactors, overpressure did not significantly affect k(L)a within the studied ranges of pressure (0.1-0.4 MPa) and superficial gas velocity in the riser (0.032-0.065 m s(-1)). Nevertheless, a positive effect on OTR was observed: it increased up to 5.4 times, surpassing by 2.3 times the oxygen transfer in a 4 dm(3) stirred tank reactor operated under standard cultivation conditions. These results contribute to the development of non-conventional reactors, especially pneumatic bioreactors operated using novel strategies for oxygen control.

  8. Calculating proper transfer prices

    Energy Technology Data Exchange (ETDEWEB)

    Dorkey, F.C. (Meliora Research Associates, Rochester, NY (United States)); Jarrell, G.A. (Univ. of Rochester, NY (United States))

    1991-01-01

    This article deals with developing a proper transfer pricing method. Decentralization is as American as baseball. While managers laud the widespread benefits of both decentralization and baseball, they often greet the term transfer price policy with a yawn. Since transfer prices are as critical to the success of decentralized firms as good pitchers are to baseball teams, this is quite a mistake on the part of our managers. A transfer price is the price charged to one division for a product or service that another division produced or provided. In many, perhaps most, decentralized organizations, the transfer pricing policies actually used are grossly inefficient and sacrifice the potential advantages of decentralization. Experience shows that far too many companies have transfer pricing policies that cost them significantly in foregone growth and profits.

  9. Waste Transfer Stations

    DEFF Research Database (Denmark)

    Christensen, Thomas Højlund

    2011-01-01

    tion and transport is usually the most costly part of any waste management system; and when waste is transported over a considerable distance or for a long time, transferring the waste from the collection vehicles to more efficient transportation may be economically beneficial. This involves...... a transfer station where the transfer takes place. These stations may also be accessible by private people, offering flexibility to the waste system, including facilities for bulky waste, household hazardous waste and recyclables. Waste transfer may also take place on the collection route from small...... satellite collection vehicles to large compacting vehicles that cannot effectively travel small streets and alleys within the inner city or in residential communities with narrow roads. However, mobile transfer is not dealt with in this chapter, which focuses on stationary transfer stations. This chapter...

  10. Experimental researches on mass and heat transfer in new typical cross-flow rotating packed bed

    Institute of Scientific and Technical Information of China (English)

    CHEN Haihui; ZENG Yingying; GAO Wenshuai

    2006-01-01

    New typical cross-flow Rotating Packed Bed(RPB)called multi-pulverizing RPB was manufactured.There is enough void in multi-pulverizing RPB,where liquid easily flows and is repeatedly pulverized by light packing,which decreases the material consumed,lightens the weight,and compacts the structure.Mass and heat transfer property in the new type PRB were studied by two experimental models.In the mass transfer model,the axial fan pumping gas press is only 100 Pa,mass transfer coefficient and volumetric mass transfer coefficient are similar to countercurrent RPB,which are an order quantity lager than that in the conventional packed tower.In the heat transfer experiment,the axial fan pumping gas press is only 120 Pa;volumetric heatwhich especially suits the treatment of large gas flow and lower gas pressure drop.

  11. Gas dynamic lasers. Citations from the NTIS data base

    Science.gov (United States)

    Carrigan, B.

    1980-07-01

    The citations cover research on kinetic and energy transfer processes, design, optics, nozzles, and performance of gas and chemical lasers relying on gas dynamic effects for lasing enhancement. Diffusion and flow studies specifically applicable to such lasers are also included. This updated bibliography contains 253 citations, 6 of which are new entries to the previous edition.

  12. Keypoint Transfer Segmentation

    OpenAIRE

    Wachinger, C.; Toews, M.; Langs, G.; Wells, W.; Golland, P.

    2015-01-01

    We present an image segmentation method that transfers label maps of entire organs from the training images to the novel image to be segmented. The transfer is based on sparse correspondences between keypoints that represent automatically identified distinctive image locations. Our segmentation algorithm consists of three steps: (i) keypoint matching, (ii) voting-based keypoint labeling, and (iii) keypoint-based probabilistic transfer of organ label maps. We introduce generative models for th...

  13. Wireless power transfer system

    OpenAIRE

    Arai, Hiroyuki

    2012-01-01

    This paper presents a survey of recent wireless power transfer systems. The issue of wireless power transfer is to achieve a highly efficient system with small positioning errors of the facilities setting. Several theories have been presented to obtain precise system design. This paper presents a summary of design theory for short range power transfer systems and detailed formulations based on a circuit model and an array of infinitesimal dipoles. In addition to these theories, this paper in...

  14. Strategic Transfer Pricing

    OpenAIRE

    Michael Alles; Srikant Datar

    1998-01-01

    Most research into cost systems has focused on their motivational implications. This paper takes a different approach, by developing a model where two oligopolistic firms strategically select their cost-based transfer prices. Duopoly models frequently assume that firms game on their choice of prices. Product prices, however, are ultimately based on the firms' transfer prices that communicate manufacturing costs to marketing departments. It is for this reason that transfer prices will have a s...

  15. Experimental and Numerical Investigation of Enhancement of Heat and Mass Transfer in Adsorbent Beds

    Institute of Scientific and Technical Information of China (English)

    LiuZhenyan; FuZhumantffu

    1994-01-01

    Some interrelated parameters of heat and mass transfer in two phases of pressure rise and constant pressure are obtained by studying the desorption processes of two kinds of cylindrical adsorbent beds.with fins and without fins.Moreover,the effects of equivalent thermal conductivity of adsorbent beds,contact thermal transfer coefficient,heat transfer of fins,condensation temperature,uncondensable gas in the adsorber are analyzed.finally,enhancement of heat and mass transfer has been attained.

  16. Gas Hydrate Growth Kinetics: A Parametric Study

    Directory of Open Access Journals (Sweden)

    Remi-Erempagamo Tariyemienyo Meindinyo

    2016-12-01

    Full Text Available Gas hydrate growth kinetics was studied at a pressure of 90 bars to investigate the effect of temperature, initial water content, stirring rate, and reactor size in stirred semi-batch autoclave reactors. The mixing energy during hydrate growth was estimated by logging the power consumed. The theoretical model by Garcia-Ochoa and Gomez for estimation of the mass transfer parameters in stirred tanks has been used to evaluate the dispersion parameters of the system. The mean bubble size, impeller power input per unit volume, and impeller Reynold’s number/tip velocity were used for analyzing observed trends from the gas hydrate growth data. The growth behavior was analyzed based on the gas consumption and the growth rate per unit initial water content. The results showed that the growth rate strongly depended on the flow pattern in the cell, the gas-liquid mass transfer characteristics, and the mixing efficiency from stirring. Scale-up effects indicate that maintaining the growth rate per unit volume of reactants upon scale-up with geometric similarity does not depend only on gas dispersion in the liquid phase but may rather be a function of the specific thermal conductance, and heat and mass transfer limitations created by the limit to the degree of the liquid phase dispersion is batched and semi-batched stirred tank reactors.

  17. Basic heat transfer

    CERN Document Server

    Bacon, D H

    2013-01-01

    Basic Heat Transfer aims to help readers use a computer to solve heat transfer problems and to promote greater understanding by changing data values and observing the effects, which are necessary in design and optimization calculations.The book is concerned with applications including insulation and heating in buildings and pipes, temperature distributions in solids for steady state and transient conditions, the determination of surface heat transfer coefficients for convection in various situations, radiation heat transfer in grey body problems, the use of finned surfaces, and simple heat exc

  18. Particle Dispersion Behaviors of Dense Gas-Particle Flows in Bubble Fluidized Bed

    OpenAIRE

    Xue Liu; Guohui Li; Sihao Lv

    2013-01-01

    An Euler-Euler two-fluid model incorporating a developed momentum transfer empirical coefficient is developed to study the particle dispersion behaviors of dense gas-particle flows in gas-fluidization reactor. In this model, the four-way couplings among gas-particles, particle-gas, and particle-particle collisions are fully considered based on kinetic theory of granular flows and an improved smooth continuous drag coefficient is utilized. Gas turbulent flow is solved by large eddy simulation....

  19. Stratum energy of coal-bed gas reservoir and their control on the coal-bed gas reservoir formation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Stratum energy of coal-bed gas reservoir, including coal-radix flexibility energy, groundwater flexibility energy and gas flexibility energy (hereinafter "three energy"), depends on the energy homeostasis system, the core process of which is the effective transfer of energy and the geological selective process. Combining with the mechanics experimentations of coal samples, different flexibility energy has been analyzed and researched quantificationally, and a profound discussion to their controls on the coal-bed gas reservoir formation has been made. It is shown that when gas reservoir is surrounded by edge water and bottom water, the deposited energy in the early phase of forming gas reservoir is mostly coal-radix and gas flexibility energy, but the effect of groundwater flexibility energy increases while water-body increases. The deposited energy in the middle and later phase of forming gas reservoir is mostly gas flexibility energy, which is greater than 80% of all deposited energy. In the whole process, larger groundwater body exerts greater influences on gas accumulation. The paper indicated that higher stratum energy is more propitious to forming coal-bed gas reservoir. And higher coal-radix flexibility energy and gas flexibility energy are more propitious to higher yield of gas reservoirs, while higher groundwater flexibility energy is more propitious to stable yield of gas reservoirs. Therefore, the key to evaluating the coal-bed gas reservoir formation is the stratum energy of coal-bed gas reservoir.

  20. EXPERIMENTAL RESEARCH OF CYLINDER-TO-BED HEAT TRANSFER IN AGITATED FLUIDIZED BEDS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Cylinder-to-bed heat transfer in agitated fluidized beds was studied experimentally.In the experiments, the aluminum particles were used as bed material, the diameter of which ranges from 0.5mm to 2mm.The effects of gas velocity, particles size, and agitator rotary speed on heat transfer were studied.From the experimental results, we have come to the following conclusions: (1) There are optimal ranges for airflow velocity and rotary speed to get optimal heat transfer coefficient; (2) The cylinder-to-bed heat transfer is greatly affected by gas velocity, rotary speed and particles sizes and the effect of rotary speed on heat transfer is similar to that of gas velocity; (3) Higher heat transfer coefficient is obtained with smaller particles.