Sample records for thermal conductivity heat

  1. Thermal conductivity and heat transfer in superlattices

    SciTech Connect (OSTI)

    Chen, G.; Neagu, M.; Borca-Tasciuc, T.

    1997-07-01T23:59:59.000Z

    Understanding the thermal conductivity and heat transfer processes in superlattice structures is critical for the development of thermoelectric materials and devices based on quantum structures. This work reports progress on the modeling of thermal conductivity of superlattice structures. Results from the models established based on the Boltzmann transport equation could explain existing experimental results on the thermal conductivity of semiconductor superlattices in both in plane and cross-plane directions. These results suggest the possibility of engineering the interfaces to further reduce thermal conductivity of superlattice structures.

  2. Thermal Conductivity of Composites Under Di erent Heating Scenarios

    E-Print Network [OSTI]

    Thermal Conductivity of Composites Under Di#11;erent Heating Scenarios H.T. Banks #3; , J.H. Hogan of composites under three di#11;erent heating scenarios: (i) a laser pulse heat source, (ii) a preheated composite sample, and (iii) a continuous heat source. 1 Introduction Adhesives such as epoxies, gels

  3. Thermally conductive cementitious grout for geothermal heat pump systems

    DOE Patents [OSTI]

    Allan, Marita (Old Field, NY)

    2001-01-01T23:59:59.000Z

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  4. An International Round-Robin Study, Part II: Thermal Diffusivity, Specific Heat and Thermal Conductivity

    SciTech Connect (OSTI)

    Wang, Hsin [ORNL; Porter, Wallace D [ORNL; Bottner, Harold [Fraunhofer-Institute, Freiburg, Germany; Konig, Jan [Fraunhofer-Institute, Freiburg, Germany; Chen, Lidong [Chinese Academy of Sciences; Bai, Shengqiang [Chinese Academy of Sciences; Tritt, Terry M. [Clemson University; Mayolett, Alex [Corning, Inc; Senawiratne, Jayantha [Corning, Inc; Smith, Charlene [Corning, Inc; Harris, Fred [ZT-Plus; Gilbert, Partricia [Marlow Industries, Inc; Sharp, J [Marlow Industries, Inc; Lo, Jason [CANMET - Materials Technology Laboratory, Natural Resources of Canada; Keinke, Holger [University of Waterloo, Canada; Kiss, Laszlo I. [University of Quebec at Chicoutimi

    2013-01-01T23:59:59.000Z

    For bulk thermoelectrics, figure-of-merit, ZT, still needs to improve from the current value of 1.0 - 1.5 to above 2 to be competitive to other alternative technologies. In recent years, the most significant improvements in ZT were mainly due to successful reduction of thermal conductivity. However, thermal conductivity cannot be measured directly at high temperatures. The combined measurements of thermal diffusivity and specific heat and density are required. It has been shown that thermal conductivity is the property with the greatest uncertainty and has a direct influence on the accuracy of the figure of merit. The International Energy Agency (IEA) group under the implementing agreement for Advanced Materials for Transportation (AMT) has conducted two international round-robins since 2009. This paper is Part II of the international round-robin testing of transport properties of bulk bismuth telluride. The main focuses in Part II are on thermal diffusivity, specific heat and thermal conductivity.

  5. eXtremes of heat conduction: Pushing the boundaries of the thermal

    E-Print Network [OSTI]

    Braun, Paul

    eXtremes of heat conduction: Pushing the boundaries of the thermal conductivity of materials David. · For example, simplest case of thermal conductivity where resistive scattering dominates C() v() l() d C for the highest thermal conductivity any material (higher conductivity than diamond) Yu et al. (2005) Maruyama

  6. Heat conduction through a trapped solid: effect of structural changes on thermal conductance

    E-Print Network [OSTI]

    Debasish Chaudhuri; Abhishek Chaudhuri; Surajit Sengupta

    2007-03-20T23:59:59.000Z

    We study the conduction of heat across a narrow solid strip trapped by an external potential and in contact with its own liquid. Structural changes, consisting of addition and deletion of crystal layers in the trapped solid, are produced by altering the depth of the confining potential. Nonequilibrium molecular dynamics simulations and, wherever possible, simple analytical calculations are used to obtain the thermal resistance in the liquid, solid and interfacial regions (Kapitza or contact resistance). We show that these layering transitions are accompanied by sharp jumps in the contact thermal resistance. Dislocations, if present, are shown to increase the thermal resistance of the strip drastically.

  7. Discrete thermal element modelling of heat conduction in particle systems: Basic formulations

    E-Print Network [OSTI]

    Martin, Ralph R.

    methodology, termed the discrete thermal element method (DTEM), for the effec- tive modelling of heat rights reserved. Keywords: Discrete thermal element method; Circular particle; Thermal contact; Heat conduction; Boundary (integral) equation/element 1. Introduction Heat transfer in particle systems can

  8. Measurement of the electronic thermal conductance channels and heat capacity of graphene at low temperature

    E-Print Network [OSTI]

    Measurement of the electronic thermal conductance channels and heat capacity of graphene at low, Gwf , test the Wiedemann-Franz (wf) law, and infer the electronic heat capacity, with a minimum value of a Coulomb-interacting electron-hole plasma may result in deviations from the Fermi-liquid values of the Mott

  9. Thermal conductivity and specific heat of sorghum grain

    E-Print Network [OSTI]

    Miller, Clinton Frank

    1963-01-01T23:59:59.000Z

    Formation of Test Canister Ice Jacket ~ Sealing Test Canister in Calorimeter. . 43 44 Testing of Samples. Initial Calorimeter Observations. 49 Insertion of Grain Samples into Calorimeter. . . . 50 Final Test Observations Processing of Data. 54... to Contain the Grain Sample 38 for the Determination of Specific Heat 39 12. Top View of Calorimeter. 40 13. Galvanized Iron Cylinder Used to Form the Ice Jacket Around the Test Canister 42 VIII Figures 14. Clamping Device Used to Hold Test Canister...

  10. Determination of temperature-dependent heat conductivity and thermal diffusivity of waste glass melter feed

    SciTech Connect (OSTI)

    Pokorny, Richard; Rice, Jarrett A.; Schweiger, Michael J.; Hrma, Pavel R.

    2013-06-01T23:59:59.000Z

    The cold cap is a layer of reacting glass batch floating on the surface of melt in an all-electric continuous glass melter. The heat needed for the conversion of the melter feed to molten glass must be transferred to and through the cold cap. Since the heat flux into the cold cap determines the rate of melting, the heat conductivity is a key property of the reacting feed. We designed an experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples that monitors the evolution of the temperature field while the crucible is heated at a constant rate. Then we used two methods to calculate the heat conductivity and thermal diffusivity of the reacting feed: the approximation of the temperature field by polynomial functions and the finite-volume method coupled with least-squares analysis. Up to 680°C, the heat conductivity of the reacting melter feed was represented by a linear function of temperature.

  11. Determination of heat conductivity and thermal diffusivity of waste glass melter feed: Extension to high temperatures

    SciTech Connect (OSTI)

    Rice, Jarrett A.; Pokorny, Richard; Schweiger, Michael J.; Hrma, Pavel R.

    2014-05-12T23:59:59.000Z

    The heat conductivity ({lambda}) and the thermal diffusivity (a) of reacting glass batch, or melter feed, control the heat flux into and within the cold cap, a layer of reacting material floating on the pool of molten glass in an all-electric continuous waste glass melter. After previously estimating {lambda} of melter feed at temperatures up to 680 deg C, we focus in this work on the {lambda}(T) function at T > 680 deg C, at which the feed material becomes foamy. We used a customized experimental setup consisting of a large cylindrical crucible with an assembly of thermocouples, which monitored the evolution of the temperature field while the crucible with feed was heated at a constant rate from room temperature up to 1100°C. Approximating measured temperature profiles by polynomial functions, we used the heat transfer equation to estimate the {lambda}(T) approximation function, which we subsequently optimized using the finite-volume method combined with least-squares analysis. The heat conductivity increased as the temperature increased until the feed began to expand into foam, at which point the conductivity dropped. It began to increase again as the foam turned into a bubble-free glass melt. We discuss the implications of this behavior for the mathematical modeling of the cold cap.

  12. Subsurface Temperature, Moisture, Thermal Conductivity and Heat Flux, Barrow, Area A, B, C, D

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Cable, William; Romanovsky, Vladimir

    Subsurface temperature data are being collected along a transect from the center of the polygon through the trough (and to the center of the adjacent polygon for Area D). Each transect has five 1.5m vertical array thermistor probes with 16 thermistors each. This dataset also includes soil pits that have been instrumented for temperature, water content, thermal conductivity, and heat flux at the permafrost table. Area C has a shallow borehole of 2.5 meters depth is instrumented in the center of the polygon.

  13. Subsurface Temperature, Moisture, Thermal Conductivity and Heat Flux, Barrow, Area A, B, C, D

    SciTech Connect (OSTI)

    Cable, William; Romanovsky, Vladimir

    2014-03-31T23:59:59.000Z

    Subsurface temperature data are being collected along a transect from the center of the polygon through the trough (and to the center of the adjacent polygon for Area D). Each transect has five 1.5m vertical array thermistor probes with 16 thermistors each. This dataset also includes soil pits that have been instrumented for temperature, water content, thermal conductivity, and heat flux at the permafrost table. Area C has a shallow borehole of 2.5 meters depth is instrumented in the center of the polygon.

  14. Coupled heat conduction and thermal stress formulation using explicit integration. [LMFBR

    SciTech Connect (OSTI)

    Marchertas, A.H.; Kulak, R.F.

    1982-06-01T23:59:59.000Z

    The formulation needed for the conductance of heat by means of explicit integration is presented. The implementation of these expressions into a transient structural code, which is also based on explicit temporal integration, is described. Comparisons of theoretical results with code predictions are given both for one-dimensional and two-dimensional problems. The coupled thermal and structural solution of a concrete crucible, when subjected to a sudden temperature increase, shows the history of cracking. The extent of cracking is compared with experimental data.

  15. Thermally conductive cementitious grouts for geothermal heat pumps. Progress report FY 1998

    SciTech Connect (OSTI)

    Allan, M.L.; Philippacopoulos, A.J.

    1998-11-01T23:59:59.000Z

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98. The developed thermally conductive grout consists of cement, water, a particular grade of silica sand, superplasticizer and a small amount of bentonite. While the primary function of the grout is to facilitate heat transfer between the U-loop and surrounding formation, it is also essential that the grout act as an effective borehole sealant. Two types of permeability (hydraulic conductivity) tests was conducted to evaluate the sealing performance of the cement-sand grout. Additional properties of the proposed grout that were investigated include bleeding, shrinkage, bond strength, freeze-thaw durability, compressive, flexural and tensile strengths, elastic modulus, Poisson`s ratio and ultrasonic pulse velocity.

  16. Impacts of Soil and Pipe Thermal Conductivity on Performance of Horizontal Pipe in a Ground-source Heat Pump

    E-Print Network [OSTI]

    Song, Y.; Yao, Y.; Na, W.

    2006-01-01T23:59:59.000Z

    In this paper the composition and thermal property of soil are discussed. The main factors that impact the soil thermal conductivity and several commonly-used pipe materials are studied. A model of heat exchanger with horizontal pipes of ground-source...

  17. Investigation into the effect of heat treatment on the thermal conductivity of 3-D carbon/carbon fiber composites

    SciTech Connect (OSTI)

    Dinwiddie, R.B.; Burchell, T.D. (Oak Ridge National Lab., TN (USA)); Baker, C.F. (Fiber Materials, Inc., Biddeford, ME (USA))

    1991-01-01T23:59:59.000Z

    The material used in this study was a carbon-carbon fiber composite manufactured from precursor yarn and petroleum based pitch through a process of repetitive densification of a woven preform. The resultant high temperature-high strength material exhibits relatively high thermal conductivity and is thus of interest to the fusion energy, plasma materials interactions (PMI) and plasma facing components (PFC) communities. Carbon-carbon fiber composite manufacture involves two distinct processes, preform weaving and component densification. In this study three samples were subjected to an additional heat treatment of 2550, 2750 or 3000{degree}C at Oak Ridge National Laboratory (ORNL) subsequent to their fourth graphitization at 2400{degree}C. It should be noted that no effort was made to optimize the composite for thermal conductivity, but rather only to provide a material with which to evaluate the effect of the final heat treatment temperature on the thermal conductivity. The fiber is the primary source of heat conduction in the composite. Consequently, increasing the fiber volume fraction, and/or the fiber thermal conductivity is expected to increase the composite thermal conductivity. 3 refs., 1 fig.

  18. Nonlinear Electron Heat Conduction Equation and Self similar method for 1-D Thermal Waves in Laser Heating of Solid Density DT Fuel

    E-Print Network [OSTI]

    A. Mohammadian Pourtalari; M. A. Jafarizadeh; M. Ghoranneviss

    2011-11-23T23:59:59.000Z

    Electron heat conduction is one of the ways that energy transports in laser heating of fusible target material. The aim of Inertial Confinement Fusion (ICF) is to show that the thermal conductivity is strongly dependent on temperature and the equation of electron heat conduction is a nonlinear equation. In this article, we solve the one-dimensional (1-D) nonlinear electron heat conduction equation with a self-similar method (SSM). This solution has been used to investigate the propagation of 1-D thermal wave from a deuterium-tritium (DT) plane source which occurs when a giant laser pulse impinges onto a DT solid target. It corresponds to the physical problem of rapid heating of a boundary layer of material in which the energy of laser pulse is released in a finite initial thickness.

  19. Simulated evolution of fractures and fracture networks subject to thermal cooling: A coupled discrete element and heat conduction model

    SciTech Connect (OSTI)

    Huang, Hai; Plummer, Mitchell; Podgorney, Robert

    2013-02-01T23:59:59.000Z

    Advancement of EGS requires improved prediction of fracture development and growth during reservoir stimulation and long-term operation. This, in turn, requires better understanding of the dynamics of the strongly coupled thermo-hydro-mechanical (THM) processes within fractured rocks. We have developed a physically based rock deformation and fracture propagation simulator by using a quasi-static discrete element model (DEM) to model mechanical rock deformation and fracture propagation induced by thermal stress and fluid pressure changes. We also developed a network model to simulate fluid flow and heat transport in both fractures and porous rock. In this paper, we describe results of simulations in which the DEM model and network flow & heat transport model are coupled together to provide realistic simulation of the changes of apertures and permeability of fractures and fracture networks induced by thermal cooling and fluid pressure changes within fractures. Various processes, such as Stokes flow in low velocity pores, convection-dominated heat transport in fractures, heat exchange between fluid-filled fractures and solid rock, heat conduction through low-permeability matrices and associated mechanical deformations are all incorporated into the coupled model. The effects of confining stresses, developing thermal stress and injection pressure on the permeability evolution of fracture and fracture networks are systematically investigated. Results are summarized in terms of implications for the development and evolution of fracture distribution during hydrofracturing and thermal stimulation for EGS.

  20. Heat Transfer -1 You are given the following information for a fluid with thermal conductivity of k = 0.0284 W/m-K that

    E-Print Network [OSTI]

    Virginia Tech

    Heat Transfer - 1 You are given the following information for a fluid with thermal conductivity the flow is laminar near the wall. a) (30 points) Determine the corresponding heat transfer coefficient the heat transfer coefficient as a function of x. c) (25 points) Determine the average heat transfer

  1. Manipulator having thermally conductive rotary joint for transferring heat from a test specimen

    DOE Patents [OSTI]

    Haney, S.J.; Stulen, R.H.; Toly, N.F.

    1983-05-03T23:59:59.000Z

    A manipulator for rotatably moving a test specimen in an ultra-high vacuum chamber includes a translational unit movable in three mutually perpendicular directions. A manipulator frame is rigidly secured to the translational unit for rotatably supporting a rotary shaft. A first copper disc is rigidly secured to an end of the rotary shaft for rotary movement within the vacuum chamber. A second copper disc is supported upon the first disc. The second disc receives a cryogenic cold head and does not rotate with the first disc. The second disc receives a cryogenic cold head and does not rotate with the first disc. A sapphire plate is interposed between the first and second discs to prevent galling of the copper material while maintaining high thermal conductivity between the first and second discs. A spring is disposed on the shaft to urge the second disc toward the first disc and compressingly engage the interposed sapphire plate. A specimen mount is secured to the first disc for rotation within the vacuum chamber. The specimen maintains high thermal conductivity with the second disc receiving the cryogenic transfer line.

  2. NANO REVIEW Open Access Thermal conductivity and thermal boundary

    E-Print Network [OSTI]

    Boyer, Edmond

    NANO REVIEW Open Access Thermal conductivity and thermal boundary resistance of nanostructures and the thermal transport prop- erties is a key point to design materials with preferred thermal properties with the heat dissipation on them. The influence of the interfacial roughness on the thermal conductivity

  3. Cermet fuel thermal conductivity

    E-Print Network [OSTI]

    Alvis, John Mark

    1988-01-01T23:59:59.000Z

    CERMET FUEL THERMAL CONDUCTIVITY A Thesis by JOHN MARK ALVIS, JR. Submitted to the Graduate College of Texas A&. M University in partial fulfilment of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Nuclear... particles of low conductivity dispersed in a metal matrix of high conductivity. A computer code was developed in order to compute the conductivity of cermet fuels as predicted by existing models and an additional model derived in this work...

  4. Critical evaluation of anomalous thermal conductivity and convective heat transfer enhancement in nanofluids

    E-Print Network [OSTI]

    Prabhat, Naveen

    2010-01-01T23:59:59.000Z

    While robust progress has been made towards the practical use of nanofluids, uncertainties remain concerning the fundamental effects of nanoparticles on key thermo-physical properties. Nanofluids have higher thermal ...

  5. Low thermal conductivity skutterudites

    SciTech Connect (OSTI)

    Fleurial, J.P.; Caillat, T.; Borshchevsky, A.

    1997-07-01T23:59:59.000Z

    Recent experimental results on semiconductors with the skutterudite crystal structure show that these materials possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Both n-type and p-type conductivity samples have been obtained, using several preparation techniques. Associated with a low hole effective mass, very high carrier mobilities, low electrical resistivities and moderate Seebeck coefficients are obtained in p-type skutterudites. For a comparable doping level, the carrier mobilities of n-type samples are about an order of magnitude lower than the values achieved on p-type samples. However, the much larger electron effective masses and Seebeck coefficients on p-type samples. However, the much larger electron effective masses and Seebeck coefficients make n-type skutterudite promising candidates as well. Unfortunately, the thermal conductivities of the binary skutterudites compounds are too large, particularly at low temperatures, to be useful for thermoelectric applications. Several approaches to the reduction of the lattice thermal conductivity in skutterudites are being pursued: heavy doping, formation of solid solutions and alloys, study of novel ternary and filled skutterudite compounds. All those approaches have already resulted in skutterudite compositions with substantially lower thermal conductivity values in these materials. Recently, superior thermoelectric properties in the moderate to high temperature range were achieved for compositions combining alloying and filling of the skutterudite structure. Experimental results and mechanisms responsible for low thermal conductivity in skutterudites are discussed.

  6. THERMALLY CONDUCTIVE CEMENTITIOUS GROUTS FOR GEOTHERMAL HEAT PUMPS. PROGRESS REPORT BY 1998

    SciTech Connect (OSTI)

    ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

    1998-11-01T23:59:59.000Z

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.

  7. Temperature, thermal-conductivity, and heat-flux data,Raft River...

    Open Energy Info (EERE)

    conductivity; United States; USGS Authors Urban, T.C.; Diment, W.H.; Nathenson, M.; Smith, E.P.; Ziagos, J.P.; Shaeffer and M.H. Published Open-File Report - U. S. Geological...

  8. Experimental thermal conductivity and contact conductance of graphite composites

    E-Print Network [OSTI]

    Jackson, Marian Christine

    1998-01-01T23:59:59.000Z

    Figure 2. 1 One-Dimensional Heat Transfer by Conduction Across a Plane Wall Figure 2. 2 Fundamental Element for Electrically Based Thermal Model. . . 14 Figure 2. 3 Rectangular Unit Cell Orientation . 14 Figure 2. 4 Model of Parabolic Distribution... a low transverse thermal conductivity, they show better thermal performance than MMC's for some weight-critical applications (Ibrahim, 1992). Graphite/organic compound composites also will be reviewed. Using a high conductivity graphite fiber...

  9. HEATS: Thermal Energy Storage

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

  10. Low Conductivity Thermal Barrier Coatings

    E-Print Network [OSTI]

    Wadley, Haydn

    Low Conductivity Thermal Barrier Coatings A Dissertation Presented to The Faculty of the School conductivity of the coatings. The minimum thermal conductivity occurs at a low rotation rate and is 0.8 W intrinsic thermal conductivity, good phase stability and greater resistance to sintering and CMAS attack

  11. Enhanced Thermal Conductivity Oxide Fuels

    SciTech Connect (OSTI)

    Alvin Solomon; Shripad Revankar; J. Kevin McCoy

    2006-01-17T23:59:59.000Z

    the purpose of this project was to investigate the feasibility of increasing the thermal conductivity of oxide fuels by adding small fractions of a high conductivity solid phase.

  12. M. Bahrami ENSC 388 (F09) Steady Conduction Heat Transfer 1 Steady Heat Conduction

    E-Print Network [OSTI]

    Bahrami, Majid

    of the material. In the limiting case where x0, the equation above reduces to the differential form: W dx dT k is the only energy interaction; the energy balance for the wall can be expressed: dt dE QQ wall outin). Thermal Conductivity Thermal conductivity k [W/mK] is a measure of a material's ability to conduct heat

  13. Thermal conductivity of thermal-battery insulations

    SciTech Connect (OSTI)

    Guidotti, R.A.; Moss, M.

    1995-08-01T23:59:59.000Z

    The thermal conductivities of a variety of insulating materials used in thermal batteries were measured in atmospheres of argon and helium using several techniques. (Helium was used to simulate the hydrogen atmosphere that results when a Li(Si)/FeS{sub 2} thermal battery ages.) The guarded-hot-plate method was used with the Min-K insulation because of its extremely low thermal conductivity. For comparison purposes, the thermal conductivity of the Min-K insulating board was also measured using the hot-probe method. The thermal-comparator method was used for the rigid Fiberfrax board and Fiberfrax paper. The thermal conductivity of the paper was measured under several levels of compression to simulate the conditions of the insulating wrap used on the stack in a thermal battery. The results of preliminary thermal-characterization tests with several silica aerogel materials are also presented.

  14. Experimental Measurement of the Interface Heat Conductance Between Nonconforming Beryllium and Type 316 Stainless Steel Surfaces Subjected to Nonuniform Thermal Deformations

    SciTech Connect (OSTI)

    Abelson, Robert Dean; Abdou, Mohamed A. [University of California, Los Angeles (United States)

    2001-03-15T23:59:59.000Z

    In fusion blanket designs that employ beryllium as a neutron multiplier, the interface conductance h plays a key role in evaluating the blanket's thermal profile. Therefore, an extensive experimental program was conducted to measure the magnitude of h between nonconforming beryllium and Type 316 stainless steel surfaces subjected to nonuniform thermal deformations. The magnitude of h was measured as a function of relevant environmental, surface, and geometric parameters, including surface roughness, contact pressure, gas pressure, gas type, and magnitude and direction of heat flow. The results indicate the following: (a) Decreasing the interfacial surface roughness from 6.28 to 0.28 {mu}m, in 760 Torr of helium, increased the magnitude of h by up to 100%; however, increasing the surface roughness reduced the dependence of h on the magnitude of the contact pressure. (b) The interface conductance was significantly higher for measurements made in helium gas as opposed to air. Additionally, the sensitivity of h to the gas pressure was significantly greater for runs conducted in helium and/or with smoother surfaces. This sensitivity was reduced in air and/or with roughened surfaces, and it was essentially nonexistent for the 6.25-{mu}m specimen for air pressures exceeding 76 Torr. (c) For runs conducted in vacuum, the interface conductance was more sensitive to heat flux than when runs were conducted in 760 Torr of helium. (d) The interface conductance was found to be dependent on the direction of heat flux. When the specimens were arranged so that heat flowed from the steel to the beryllium disk, the magnitude of h was generally greater than in the opposite direction.

  15. An Innovative High Thermal Conductivity Fuel Design

    SciTech Connect (OSTI)

    Jamil A. Khan

    2009-11-21T23:59:59.000Z

    Thermal conductivity of the fuel in today's Light Water Reactors, Uranium dioxide, can be improved by incorporating a uniformly distributed heat conducting network of a higher conductivity material, Silicon Carbide. The higher thermal conductivity of SiC along with its other prominent reactor-grade properties makes it a potential material to address some of the related issues when used in UO2 [97% TD]. This ongoing research, in collaboration with the University of Florida, aims to investigate the feasibility and develop a formal methodology of producing the resultant composite oxide fuel. Calculations of effective thermal conductivity of the new fuel as a function of %SiC for certain percentages and as a function of temperature are presented as a preliminary approach. The effective thermal conductivities are obtained at different temperatures from 600K to 1600K. The corresponding polynomial equations for the temperature-dependent thermal conductivities are given based on the simulation results. Heat transfer mechanism in this fuel is explained using a finite volume approach and validated against existing empirical models. FLUENT 6.1.22 was used for thermal conductivity calculations and to estimate reduction in centerline temperatures achievable within such a fuel rod. Later, computer codes COMBINE-PC and VENTURE-PC were deployed to estimate the fuel enrichment required, to maintain the same burnup levels, corresponding to a volume percent addition of SiC.

  16. Gas storage carbon with enhanced thermal conductivity

    DOE Patents [OSTI]

    Burchell, Timothy D. (Oak Ridge, TN); Rogers, Michael Ray (Knoxville, TN); Judkins, Roddie R. (Knoxville, TN)

    2000-01-01T23:59:59.000Z

    A carbon fiber carbon matrix hybrid adsorbent monolith with enhanced thermal conductivity for storing and releasing gas through adsorption and desorption is disclosed. The heat of adsorption of the gas species being adsorbed is sufficiently large to cause hybrid monolith heating during adsorption and hybrid monolith cooling during desorption which significantly reduces the storage capacity of the hybrid monolith, or efficiency and economics of a gas separation process. The extent of this phenomenon depends, to a large extent, on the thermal conductivity of the adsorbent hybrid monolith. This invention is a hybrid version of a carbon fiber monolith, which offers significant enhancements to thermal conductivity and potential for improved gas separation and storage systems.

  17. Thermal Conductivity of High-Modulus Polymer Fibers Xiaojia Wang,*,

    E-Print Network [OSTI]

    Cahill, David G.

    to be the dominate carriers of heat. 1. INTRODUCTION Polymeric materials typically have a low thermal conductivity transfer is critical are often limited by low thermal conductivity. Here, we leverage the enormous research and low-density PE with varying fiber volume fractions.11 They reported an axial thermal conductivity

  18. Effective Thermal Conductivity of Graded Nanocomposites with Interfacial Thermal

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    .M. Yin", G. H. Paulino", W.G. Buttlar", and L.Z. Sun'' '^Department of Civil and Environmental the effective thermal conductivity distribution in functionally graded materials (FGMs) considering the Kapitza is developed to derive the averaged heat flux field of the particle phase. Then the temperature gradient can

  19. Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders

    SciTech Connect (OSTI)

    Johnson, Matthew (DOE/NNSA Kansas City Plant (United States)); Weyant, J.; Garner, S. (Advanced Cooling Technologies, Inc. (Lancaster, PA (United States)); Occhionero, M. (CPS Technologies Corporation, Norton, MA (United States))

    2010-01-07T23:59:59.000Z

    Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate’s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.

  20. Thermal conductivity of electroless nickel-phosphorus alloy plating

    SciTech Connect (OSTI)

    Smith, D.D.

    1982-04-01T23:59:59.000Z

    Properties of specific heat, thermal diffusivity, density, and calculated thermal conductivity have been determined for a modified acid bath electroless nickel-12.7 wt% phosphorus alloy between 298 ad 423 K. Thermal conductivity values are about half those of pure nickel.

  1. Continuous Processing of High Thermal Conductivity Polyethylene...

    Broader source: Energy.gov (indexed) [DOE]

    Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Continuous Processing of High Thermal Conductivity Polyethylene Fibers and Sheets Massachusetts Institute of...

  2. Analysis of the Temporal Evolution of Thermal Conductivity in Alumina-Water Nanofluid

    E-Print Network [OSTI]

    Fortenberry, Stephen

    2009-09-30T23:59:59.000Z

    both the United States Department of Energy and Texas Advanced Research Program. vi NOMENCLATURE D Thermal diffusivity Ei Exponential integral k Thermal conductivity k n Nanofluid thermal conductivity k b Base fluid thermal...?s thermal conductivity (k) and thermal diffusivity (D), are related to the temperature difference null?nullnull between the heat source and surrounding medium at a distance (r) from the source of a quantity of heat (Q) a certain time (t) after the heat...

  3. Force and heat current formulas for many-body potentials in molecular dynamics simulation with applications to thermal conductivity calculations

    E-Print Network [OSTI]

    Fan, Zheyong; Wang, Hui-Qiong; Zheng, Jin-Cheng; Donadio, Davide; Harju, Ari

    2015-01-01T23:59:59.000Z

    We derive expressions of interatomic force and heat current for many-body potentials such as the Tersoff, the Brenner, and the Stillinger-Weber potential used extensively in molecular dynamics simulations of covalently bonded materials. Although these potentials have a many-body nature, a pairwise force expression that follows Newton's third law can be found without referring to any partition of the potential. Based on this force formula, a stress applicable for periodic systems can be unambiguously defined. The force formula can then be used to derive the heat current formulas using a natural potential partitioning. Our heat current formulation is found to be equivalent to most of the seemingly different heat current formulas used in the literature, but to deviate from the stress-based formula derived from two-body potential. We validate our formulation numerically on various systems descried by the Tersoff potential, namely three-dimensional silicon and diamond, two-dimensional graphene, and quasi-one-dimen...

  4. Design of a novel conduction heating based stress-thermal cycling apparatus for composite materials and its utilization to characterize composite microcrack damage thresholds

    E-Print Network [OSTI]

    Ju, Jaehyung

    2006-10-30T23:59:59.000Z

    performed as a function of mechanical inplane strain levels, heating rates, and number of thermal cycles. The apparatus generated cracks related to the in-plane stresses (or strains) on plies. The design and analysis concept of the synergistic stress...

  5. Experimental investigations of solid-solid thermal interface conductance

    E-Print Network [OSTI]

    Collins, Kimberlee C. (Kimberlee Chiyoko)

    2010-01-01T23:59:59.000Z

    Understanding thermal interface conductance is important for nanoscale systems where interfaces can play a critical role in heat transport. In this thesis, pump and probe transient thermoreflectance methods are used to ...

  6. Thermal Conductivity of Polycrystalline Semiconductors and Ceramics

    E-Print Network [OSTI]

    Wang, Zhaojie

    2012-01-01T23:59:59.000Z

    semiconductors and ceramics with desired thermalthermal conductivity of several polycrystalline semiconductors and ceramics,Thermal Conductivity of Polycrystalline Semiconductors and Ceramics

  7. Reduced Thermal Conductivity of Compacted Silicon Nanowires

    E-Print Network [OSTI]

    Yuen, Taylor S.

    Thermal-Barrier-Coating Applications,” Journa of American Ceramicthermal conductivity materials are typically found among ceramicsThermal Conductivity of Porous Materials: Application to Thick Barrier Coatings,” Journal of the European Ceramic

  8. Thermal Conductivity and Noise Attenuation in

    E-Print Network [OSTI]

    Cambridge, University of

    .3.4 Corrosion-resistant and high-temperature filters 9 1.3.5 Acoustic Applications 9 2. THERMAL CONDUCTIVITY 2.1 THERMAL RESISTANCE 2.1.1 Thermal Conductors in Series 12 2.1.2 Thermal conductors in parallel 13 2 difference RTH Thermal resistance of conductor sb Stefan's constant T4 Temperature difference K* Total

  9. THERMAL CONDUCTIVITY AND OTHER PROPERTIES OF CEMENTITIOUS GROUTS

    SciTech Connect (OSTI)

    ALLAN,M.

    1998-05-01T23:59:59.000Z

    The thermal conductivity and other properties cementitious grouts have been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. In addition to thermal conductivity, the cementitious grouts were also tested for bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the results for selected grout mixes. Relatively high thermal conductivities were obtained and this leads to reduction in predicted bore length and installation costs. Improvements in shrinkage resistance and bonding were achieved.

  10. Enhanced Thermal Conductivity of Water with Surfactant Encapsulated and Individualized Single-Walled Carbon Nanotube Dispersions

    E-Print Network [OSTI]

    Maruyama, Shigeo

    .L, Review of heat conduction in nanofluids, Journal of Heat transfer, 2011, 133, pp 040801-1-040801-14. #12; layering were considered to be responsible for the thermal conductivity enhancement in the open literature

  11. In-Pile Thermal Conductivity Measurement Method for Nuclear Fuels

    SciTech Connect (OSTI)

    Joy L. Rempe; Brandon Fox; Heng Ban; Joshua E. Daw; Darrell L. Knudson; Keith G. Condie

    2009-08-01T23:59:59.000Z

    Thermophysical properties of advanced nuclear fuels and materials during irradiation must be known prior to their use in existing, advanced, or next generation reactors. Thermal conductivity is one of the most important properties for predicting fuel and material performance. A joint Utah State University (USU) / Idaho National Laboratory (INL) project, which is being conducted with assistance from the Institute for Energy Technology at the Norway Halden Reactor Project, is investigating in-pile fuel thermal conductivity measurement methods. This paper focuses on one of these methods – a multiple thermocouple method. This two-thermocouple method uses a surrogate fuel rod with Joule heating to simulate volumetric heat generation to gain insights about in-pile detection of thermal conductivity. Preliminary results indicated that this method can measure thermal conductivity over a specific temperature range. This paper reports the thermal conductivity values obtained by this technique and compares these values with thermal property data obtained from standard thermal property measurement techniques available at INL’s High Test Temperature Laboratory. Experimental results and material properties data are also compared to finite element analysis results.

  12. Process for fabricating composite material having high thermal conductivity

    DOE Patents [OSTI]

    Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

    2001-01-01T23:59:59.000Z

    A process for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost.

  13. High thermal power density heat transfer apparatus providing electrical isolation at high temperature using heat pipes

    SciTech Connect (OSTI)

    Morris, J. F.

    1985-03-19T23:59:59.000Z

    This invention is directed to transferring heat from an extremely high temperature source to an electrically isolated lower temperature receiver. The invention is particularly concerned with supplying thermal power to a thermionic converter from a nuclear reactor with electric isolation. Heat from a high temperature heat pipe is transferred through a vacuum or a gap filled with electrically nonconducting gas to a cooler heat pipe. The heat pipe is used to cool the nuclear reactor while the heat pipe is connected thermally and electrically to a thermionic converter. If the receiver requires greater thermal power density, geometries are used with larger heat pipe areas for transmitting and receiving energy than the area for conducting the heat to the thermionic converter. In this way the heat pipe capability for increasing thermal power densities compensates for the comparatively low thermal power densities through the electrically nonconducting gap between the two heat pipes.

  14. Thermal conductivity measurements of Summit polycrystalline silicon.

    SciTech Connect (OSTI)

    Clemens, Rebecca; Kuppers, Jaron D.; Phinney, Leslie Mary

    2006-11-01T23:59:59.000Z

    A capability for measuring the thermal conductivity of microelectromechanical systems (MEMS) materials using a steady state resistance technique was developed and used to measure the thermal conductivities of SUMMiT{trademark} V layers. Thermal conductivities were measured over two temperature ranges: 100K to 350K and 293K to 575K in order to generate two data sets. The steady state resistance technique uses surface micromachined bridge structures fabricated using the standard SUMMiT fabrication process. Electrical resistance and resistivity data are reported for poly1-poly2 laminate, poly2, poly3, and poly4 polysilicon structural layers in the SUMMiT process from 83K to 575K. Thermal conductivity measurements for these polysilicon layers demonstrate for the first time that the thermal conductivity is a function of the particular SUMMiT layer. Also, the poly2 layer has a different variation in thermal conductivity as the temperature is decreased than the poly1-poly2 laminate, poly3, and poly4 layers. As the temperature increases above room temperature, the difference in thermal conductivity between the layers decreases.

  15. A study of temperature distributions due to conduction reservoir heating

    E-Print Network [OSTI]

    Connaughton, Charles Richard

    2012-06-07T23:59:59.000Z

    of thermal conductivity with temperature. He showed this effect could be very important in considering a material such as oil shale, where the conductivity of the raw shale may be five times as great as that of the spent shale. Neglecting this variation... conduction model to investigate the in place heating of oil shale by hot gases forced through a fracture. The heat injection rate he considered is much less than would normally be employed for steam injection into permeable reservoirs and is only about...

  16. Heat Transfer Derivation of differential equations for heat transfer conduction

    E-Print Network [OSTI]

    Veress, Alexander

    ) or kW *h or Btu. U is the change in stored energy, in units of kW *h (kWh) or Btu. qx is the heat conducted (heat flux) into the control volume at surface edge x, in units of kW/m2 or Btu/(h-ft2). qx volume is positive), in kW/m3 or Btu/(h-ft3) (a heat sink, heat drawn out of the volume, is negative

  17. Fourier analysis of conductive heat transfer for glazed roofing materials

    SciTech Connect (OSTI)

    Roslan, Nurhana Lyana; Bahaman, Nurfaradila; Almanan, Raja Noorliyana Raja; Ismail, Razidah [Faculty of Computer and Mathematical Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia); Zakaria, Nor Zaini [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

    2014-07-10T23:59:59.000Z

    For low-rise buildings, roof is the most exposed surface to solar radiation. The main mode of heat transfer from outdoor via the roof is conduction. The rate of heat transfer and the thermal impact is dependent on the thermophysical properties of roofing materials. Thus, it is important to analyze the heat distribution for the various types of roofing materials. The objectives of this paper are to obtain the Fourier series for the conductive heat transfer for two types of glazed roofing materials, namely polycarbonate and polyfilled, and also to determine the relationship between the ambient temperature and the conductive heat transfer for these materials. Ambient and surface temperature data were collected from an empirical field investigation in the campus of Universiti Teknologi MARA Shah Alam. The roofing materials were installed on free-standing structures in natural ventilation. Since the temperature data are generally periodic, Fourier series and numerical harmonic analysis are applied. Based on the 24-point harmonic analysis, the eleventh order harmonics is found to generate an adequate Fourier series expansion for both glazed roofing materials. In addition, there exists a linear relationship between the ambient temperature and the conductive heat transfer for both glazed roofing materials. Based on the gradient of the graphs, lower heat transfer is indicated through polyfilled. Thus polyfilled would have a lower thermal impact compared to polycarbonate.

  18. Electrical and thermal conductivities in dense plasmas

    SciTech Connect (OSTI)

    Faussurier, G., E-mail: gerald.faussurier@cea.fr; Blancard, C.; Combis, P.; Videau, L. [CEA, DAM, DIF, F-91297 Arpajon (France)

    2014-09-15T23:59:59.000Z

    Expressions for the electrical and thermal conductivities in dense plasmas are derived combining the Chester-Thellung-Kubo-Greenwood approach and the Kramers approximation. The infrared divergence is removed assuming a Drude-like behaviour. An analytical expression is obtained for the Lorenz number that interpolates between the cold solid-state and the hot plasma phases. An expression for the electrical resistivity is proposed using the Ziman-Evans formula, from which the thermal conductivity can be deduced using the analytical expression for the Lorenz number. The present method can be used to estimate electrical and thermal conductivities of mixtures. Comparisons with experiment and quantum molecular dynamics simulations are done.

  19. Thermal conductivity of bulk nanostructured lead telluride

    SciTech Connect (OSTI)

    Hori, Takuma [Department of Mechanical Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8656 (Japan); Chen, Gang [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Shiomi, Junichiro, E-mail: shiomi@photon.t.u-tokyo.ac.jp [Department of Mechanical Engineering, The University of Tokyo, Bunkyo, Tokyo 113-8656 (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

    2014-01-13T23:59:59.000Z

    Thermal conductivity of lead telluride with embedded nanoinclusions was studied using Monte Carlo simulations with intrinsic phonon transport properties obtained from first-principles-based lattice dynamics. The nanoinclusion/matrix interfaces were set to completely reflect phonons to model the maximum interface-phonon-scattering scenario. The simulations with the geometrical cross section and volume fraction of the nanoinclusions matched to those of the experiment show that the experiment has already reached the theoretical limit of thermal conductivity. The frequency-dependent analysis further identifies that the thermal conductivity reduction is dominantly attributed to scattering of low frequency phonons and demonstrates mutual adaptability of nanostructuring and local disordering.

  20. Increased thermal conductivity monolithic zeolite structures

    DOE Patents [OSTI]

    Klett, James (Knoxville, TN); Klett, Lynn (Knoxville, TN); Kaufman, Jonathan (Leonardtown, MD)

    2008-11-25T23:59:59.000Z

    A monolith comprises a zeolite, a thermally conductive carbon, and a binder. The zeolite is included in the form of beads, pellets, powders and mixtures thereof. The thermally conductive carbon can be carbon nano-fibers, diamond or graphite which provide thermal conductivities in excess of about 100 W/mK to more than 1,000 W/mK. A method of preparing a zeolite monolith includes the steps of mixing a zeolite dispersion in an aqueous colloidal silica binder with a dispersion of carbon nano-fibers in water followed by dehydration and curing of the binder is given.

  1. New equation calculates thermal conductivities of C[sub 1]-C[sub 4] gases

    SciTech Connect (OSTI)

    Yaws, C.L.; Lin, X.; Bu, L.; Nijhawan, S. (Lamar Univ., Beaumont, TX (United States))

    1994-04-18T23:59:59.000Z

    In the design of heat exchangers, heat-transfer coefficients are commonly calculated for individual items. These calculations require knowledge of the thermal conductivities of the species involved. The calculation require knowledge of the thermal conductivities of the species involved. The calculation of the overall heat-transfer coefficient for a heat exchanger also requires thermal conductivity data for the individual species. In fact, thermal conductivity is the fundamental property involved in heat transfer. Ordinarily, thermal conductivities are either measured experimentally or estimated using complex correlations and models. Engineers must search existing literature for the values needed. Here, a compilation of thermal conductivity data for gases is presented for a wide temperature range. Using these data with the accompanying equation will enable engineers to quickly determine values at the desired temperatures. The results are provided in an easy-to-use tabular format, which is especially helpful for rapid calculations using a personal computer or hand-held calculator.

  2. Fiber/Matrix Interfacial Thermal Conductance Effect on the Thermal Conductivity of SiC/SiC Composites

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Henager, Charles H.

    2013-04-20T23:59:59.000Z

    SiC/SiC composites used in fusion reactor applications are subjected to high heat fluxes and require knowledge and tailoring of their in-service thermal conductivity. Accurately predicting the thermal conductivity of SiC/SiC composites as a function of temperature will guide the design of these materials for their intended use, which will eventually include the effects of 14-MeV neutron irradiations. This paper applies an Eshelby-Mori-Tanaka approach (EMTA) to compute the thermal conductivity of unirradiated SiC/SiC composites. The homogenization procedure includes three steps. In the first step EMTA computes the homogenized thermal conductivity of the unidirectional (UD) SiC fiber embraced by its coating layer. The second step computes the thermal conductivity of the UD composite formed by the equivalent SiC fibers embedded in a SiC matrix, and finally the thermal conductivity of the as-formed SiC/SiC composite is obtained by averaging the solution for the UD composite over all possible fiber orientations using the second-order fiber orientation tensor. The EMTA predictions for the transverse thermal conductivity of several types of SiC/SiC composites with different fiber types and interfaces are compared to the predicted and experimental results by Youngblood et al.

  3. Thermal Conductivity in Nanocrystalline Ceria Thin Films

    SciTech Connect (OSTI)

    Marat Khafizov; In-Wook Park; Aleksandr Chernatynskiy; Lingfeng He; Jianliang Lin; John J. Moore; David Swank; Thomas Lillo; Simon R. Phillpot; Anter El-Azab; David H. Hurley

    2014-02-01T23:59:59.000Z

    The thermal conductivity of nanocrystalline ceria films grown by unbalanced magnetron sputtering is determined as a function of temperature using laser-based modulated thermoreflectance. The films exhibit significantly reduced conductivity compared with stoichiometric bulk CeO2. A variety of microstructure imaging techniques including X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron analysis, and electron energy loss spectroscopy indicate that the thermal conductivity is influenced by grain boundaries, dislocations, and oxygen vacancies. The temperature dependence of the thermal conductivity is analyzed using an analytical solution of the Boltzmann transport equation. The conclusion of this study is that oxygen vacancies pose a smaller impediment to thermal transport when they segregate along grain boundaries.

  4. Ultralow Thermal Conductivity in Organoclay Nanolaminates Synthesized via Simple Self-Assembly

    E-Print Network [OSTI]

    Braun, Paul

    transform fully dense solids into ultralow thermal conductivity materials. Here we report a simple self of nanolaminate spacing. A simple series resistance model describes the behavior and gives an interfacial thermal thermal conductance For phonon-mediated heat conduction, a material is generally thought to reach its

  5. Effect of interfacial interactions on the thermal conductivity and interfacial thermal conductance in tungsten–graphene layered structure

    SciTech Connect (OSTI)

    Jagannadham, K., E-mail: jag-kasichainula@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-09-01T23:59:59.000Z

    Graphene film was deposited by microwave plasma assisted deposition on polished oxygen free high conductivity copper foils. Tungsten–graphene layered film was formed by deposition of tungsten film by magnetron sputtering on the graphene covered copper foils. Tungsten film was also deposited directly on copper foil without graphene as the intermediate film. The tungsten–graphene–copper samples were heated at different temperatures up to 900?°C in argon atmosphere to form an interfacial tungsten carbide film. Tungsten film deposited on thicker graphene platelets dispersed on silicon wafer was also heated at 900?°C to identify the formation of tungsten carbide film by reaction of tungsten with graphene platelets. The films were characterized by scanning electron microscopy, Raman spectroscopy, and x-ray diffraction. It was found that tungsten carbide film formed at the interface upon heating only above 650?°C. Transient thermoreflectance signal from the tungsten film surface on the samples was collected and modeled using one-dimensional heat equation. The experimental and modeled results showed that the presence of graphene at the interface reduced the cross-plane effective thermal conductivity and the interfacial thermal conductance of the layer structure. Heating at 650 and 900?°C in argon further reduced the cross-plane thermal conductivity and interface thermal conductance as a result of formation nanocrystalline tungsten carbide at the interface leading to separation and formation of voids. The present results emphasize that interfacial interactions between graphene and carbide forming bcc and hcp elements will reduce the cross-plane effective thermal conductivity in composites.

  6. Fabrication and Characterization of a Conduction Cooled Thermal Neutron Filter

    SciTech Connect (OSTI)

    Heather Wampler; Adam Gerth; Heng Ban; Donna Post Guillen; Douglas Porter; Cynthia Papesch

    2010-06-01T23:59:59.000Z

    Installation of a conduction cooled thermal (low-energy) neutron filter in an existing domestic test reactor would provide the U.S. the capability to test new reactor fuels and materials for advanced fast (high-energy) reactor concepts. A composite consisting of Al3Hf-Al has been proposed for the neutron filter due to both the neutron filtering properties of hafnium and the conducting capabilities of aluminum. Knowledge of the thermal conductivity of the Al3Hf-Al composite is essential for the design of the filtering system. The present objectives are to identify a suitable fabrication technique and to measure the thermophysical properties of the Al3Hf intermetallic, which has not been done previous to this study. A centrifugal casting method was used to prepare samples of Al3Hf. X-ray diffraction and Rietveld analysis were conducted to determine the structural make-up of each of the samples. Thermophysical properties were measured as follows: specific heat by a differential scanning calorimeter (DSC), thermal diffusivity by a laser flash thermal diffusivity measuring system, thermal expansion by a dilatometer, and thermal conductivity was calculated based on the previous measurements. All measurements were acquired over a temperature range of 90°C - 375°C with some measurements outside these bounds. The average thermal conductivity of the intermetallic Al3Hf (~7 at.% Hf) was found to be ~ 41 W/m-K for the given temperature range. This information fills a knowledge gap in the thermophysical properties of the intermetallic Al3Hf with the specified percentage of hafnium. A model designed to predict composite properties was used to calculate a thermal conductivity of ~177 W/m-K for an Al3Hf-Al composite with 23 vol% Al3Hf. This calculation was based upon the average thermal conductivity of Al3Hf over the specified temperature range.

  7. Measuring Thermal Transport in Extreme Environments: Thermal Conductivity

    E-Print Network [OSTI]

    Braun, Paul

    Chen California Institute of Technology Jackie Li University of Michigan supported by CarnegieMeasuring Thermal Transport in Extreme Environments: Thermal Conductivity of Water Ice VII to 20 GPa David G. Cahill, Wen-Pin Hsieh, Dallas Trinkle, University of Illinois at Urbana-Champaign Bin

  8. Heat conduction of single-walled carbon nanotube isotope-superlattice structures: A molecular dynamics study

    E-Print Network [OSTI]

    Maruyama, Shigeo

    -folding effect to thermal boundary resistance of lattice interface. The crossover mechanism is explained-dimensional materials. In our previous molecular dynamics study, isotope-effects on the thermal conduction were of heat conduction of SWNTs subjected to nanoscale intrinsic thermal resistances. Here, in order to reduce

  9. Molecular Dynamic Study of Thermal Conductivity of Amorphous Nanoporous Silica

    E-Print Network [OSTI]

    Coquil, Thomas; Fang, Jin; Pilon, Laurent

    2011-01-01T23:59:59.000Z

    as a thermal isolation layer”. Ceramics International, 34(Thermal conductivity of highly porous zirconia”. Journal of the European Ceramic

  10. Extremal structures of multiphase heat conducting composites

    E-Print Network [OSTI]

    Cherkaev, Andrej

    Extremal structures of multiphase heat conducting composites A.V. Cherkaev \\Lambda L.V. Gibiansky y April 19, 1995 Abstract In this paper we construct microstructures of multiphase composites with un be easily gen­ eralized for the three­dimensional composites with arbitrary number of phases. 1 Introduction

  11. Heat conductivity of a pion gas

    E-Print Network [OSTI]

    Antonio Dobado Gonzalez; Felipe J. Llanes-Estrada; Juan M. Torres Rincon

    2007-02-13T23:59:59.000Z

    We evaluate the heat conductivity of a dilute pion gas employing the Uehling-Uehlenbeck equation and experimental phase-shifts parameterized by means of the SU(2) Inverse Amplitude Method. Our results are consistent with previous evaluations. For comparison we also give results for an (unphysical) hard sphere gas.

  12. INFLUENCE OF ANISOTROPIC THERMAL CONDUCTIVITY IN THE APPARATUS INSULATION FOR SUBLIMATION GROWTH OF SIC

    E-Print Network [OSTI]

    INFLUENCE OF ANISOTROPIC THERMAL CONDUCTIVITY IN THE APPARATUS INSULATION FOR SUBLIMATION GROWTH insulation for sublimation growth of SiC: Numerical investigation of heat transfer J¨urgen Geiser, Olaf Klein). As it is not unusual for the thermal insulation of PVT growth apparatus to possess an anisotropic thermal conductivity

  13. IEEE TRANSACTIONS ON COMPONENTS AND PACKAGING TECHNOLOGIES, VOL. 25, NO. 4, DECEMBER 2002 615 In-Plane Effective Thermal Conductivity of

    E-Print Network [OSTI]

    Wirtz, Richard A.

    material. Thermal conductivity of second phase material. . . Heat flux. Mesh numbers along. Effective thermal resistance. Thermal diffusivity. Specific surface area. Porosity. Time. Manuscript effect, the effective thermal conductivity of these materials, is relatively small, so that much

  14. Continuous Processing of High Thermal Conductivity Fibers and...

    Broader source: Energy.gov (indexed) [DOE]

    We are developing a continuous fabrication process for high thermal conductivity polyethylene (PE) films While high thermal conductivity in (PE) has been shown in isolated...

  15. Glass-like thermal conductivity in high efficiency thermoelectric...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Glass-like thermal conductivity in high efficiency thermoelectric materials Glass-like thermal conductivity in high efficiency thermoelectric materials Discusses strategies to...

  16. VALIDATION OF A THERMAL CONDUCTIVITY MEASUREMENT SYSTEM FOR FUEL COMPACTS

    SciTech Connect (OSTI)

    Jeff Phillips; Colby Jensen; Changhu Xing; Heng Ban

    2011-03-01T23:59:59.000Z

    A high temperature guarded-comparative-longitudinal heat flow measurement system has been built to measure the thermal conductivity of a composite nuclear fuel compact. It is a steady-state measurement device designed to operate over a temperature range of 300 K to 1200 K. No existing apparatus is currently available for obtaining the thermal conductivity of the composite fuel in a non-destructive manner due to the compact’s unique geometry and composite nature. The current system design has been adapted from ASTM E 1225. As a way to simplify the design and operation of the system, it uses a unique radiative heat sink to conduct heat away from the sample column. A finite element analysis was performed on the measurement system to analyze the associated error for various operating conditions. Optimal operational conditions have been discovered through this analysis and results are presented. Several materials have been measured by the system and results are presented for stainless steel 304, inconel 625, and 99.95% pure iron covering a range of thermal conductivities of 10 W/m*K to 70 W/m*K. A comparison of the results has been made to data from existing literature.

  17. Nanoscale thermal transport and the thermal conductance of interfaces

    E-Print Network [OSTI]

    Braun, Paul

    -8 2008 #12;Er-fiber laser system, UIUC Nov. 2007 #12;Solid-liquid interfaces: Two approaches · Transient-wide: ­ thermal interface materials ­ so-called "nanofluids" (suspensions in liquids) ­ polymer composites absorption depends on temperature of the nanotube · Assume heat capacity is comparable to graphite · Cooling

  18. THERMAL CONDUCTIVITY OF NON-REPOSITORY LITHOSTRATIGRAPHIC LAYERS

    SciTech Connect (OSTI)

    R. JONES

    2004-10-22T23:59:59.000Z

    This model report addresses activities described in ''Technical Work Plan for: Near-Field Environment and Transport Thermal Properties and Analysis Reports Integration'' (BSC 2004 [DIRS 171708]). The model develops values for thermal conductivity, and its uncertainty, for the nonrepository layers of Yucca Mountain; in addition, the model provides estimates for matrix porosity and dry bulk density for the nonrepository layers. The studied lithostratigraphic units, as identified in the ''Geologic Framework Model'' (GFM 2000) (BSC 2004 [DIRS 170029]), are the Timber Mountain Group, the Tiva Canyon Tuff, the Yucca Mountain Tuff, the Pah Canyon Tuff, the Topopah Spring Tuff (excluding the repository layers), the Calico Hills Formation, the Prow Pass Tuff, the Bullfrog Tuff, and the Tram Tuff. The deepest model units of the GFM (Tund and Paleozoic) are excluded from this study because no data suitable for model input are available. The parameter estimates developed in this report are used as input to various models and calculations that simulate heat transport through the rock mass. Specifically, analysis model reports that use product output from this report are: (1) Drift-scale coupled processes (DST and TH seepage) models; (2) Drift degradation analysis; (3) Multiscale thermohydrologic model; and (4) Ventilation model and analysis report. In keeping with the methodology of the thermal conductivity model for the repository layers in ''Thermal Conductivity of the Potential Repository Horizon'' (BSC 2004 [DIRS 169854]), the Hsu et al. (1995 [DIRS 158073]) three-dimensional (3-D) cubic model (referred to herein as ''the Hsu model'') was used to represent the matrix thermal conductivity as a function of the four parameters (matrix porosity, thermal conductivity of the saturating fluid, thermal conductivity of the solid, and geometric connectivity of the solid). The Hsu model requires input data from each test specimen to meet three specific conditions: (1) Known value for matrix porosity; (2) Known values for wet and dry thermal conductivity; and (3) The location of the measured specimen in relation to the model stratigraphic unit. The only matrix thermal conductivity values developed are limited to fully saturated and dry conditions. The model does not include the effects of convection and thermal radiation in voids. The model does not include temperature dependence of thermal conductivity, porosity, or bulk density.

  19. The Thermal Conductivity of Low Density Concretes Containing Perlite

    E-Print Network [OSTI]

    Yarbrough, D. W.

    -Tov, "HEATING5 - An IBM 360 Heat Conduction Program," ORNL/CSD/tm-15(1977). Oak Ridge National Laboratory, Oak Ridge, TN 37831. [5J Expanded Shale Clay and Slate Institute, "Lightweight Concrete Information Sheet," No.4, Washington, D.C., 1958. [6J Moore..., J. P., R. S. Graves, J. G. Stradley, J. H. Hannah, and D. L. McElroy, "Some Thermal Transport Properties of a Limestone Concrete," ORNL/TM-2644 (August 1969), Oak Ridge National Laboratory, Oak Ridge, TN 37831. [7J Valore, R. C., Jr., "Cellular...

  20. Measurement of thermal conductivity P t BPart B

    E-Print Network [OSTI]

    Braun, Paul

    wave Take the Fourier transform of this frequency domain solution #12;For a low thermal conductivity thin filmFor a low thermal conductivity thin film on a high thermal conductivity substrate (Factor of 2Measurement of thermal conductivity Part A: P t BPart B: · Time domain thermoreflectance #12

  1. Developing a High Thermal Conductivity Fuel with Silicon Carbide Additives

    SciTech Connect (OSTI)

    Ronald baney; James Tulenko

    2012-11-20T23:59:59.000Z

    The objective of this research is to increase the thermal conductivity of uranium oxide (UO{sub 2}) without significantly impacting its neutronic properties. The concept is to incorporate another high thermal conductivity material, silicon carbide (SiC), in the form of whiskers or from nanoparticles of SiC and a SiC polymeric precursor into UO{sub 2}. This is expected to form a percolation pathway lattice for conductive heat transfer out of the fuel pellet. The thermal conductivity of SiC would control the overall fuel pellet thermal conductivity. The challenge is to show the effectiveness of a low temperature sintering process, because of a UO{sub 2}-SiC reaction at 1,377°C, a temperature far below the normal sintering temperature. Researchers will study three strategies to overcome the processing difficulties associated with pore clogging and the chemical reaction of SiC and UO{sub 2} at temperatures above 1,300°C:

  2. Mesoscopic simulations of phase distribution effects on the effective thermal conductivity of microgranular porous media.

    E-Print Network [OSTI]

    Wang, Moran; Pan, Ning; Wang, Jinku; Chen, Shiyi

    2007-01-01T23:59:59.000Z

    of transport in open-cell metal foam. J. Heat Transfer ASMEopen-celled metal foam model for thermal applications. J. Heat Transferheat transfer is a non-negligible factor for thermal transports in high-porosity low-conductivity open-

  3. The measurement of thermal conductivity of jelly from 25 to 95 C

    E-Print Network [OSTI]

    Chen, Yih-Rong

    1985-01-01T23:59:59.000Z

    line heat source method, the thermal con- ductivities of a jelly model (unflavored jelly), sugar solution and some commercial jelly products were measured. The studies were conducted in the temperature range from 25 to 95 'C. Thermal conductivity... were developed from experimental data for unflavored jelly and sugar solutions to predict the thermal conductivity of commercially available fruit jellies at various moisture contents. The predicted values obtained were statistically compared...

  4. Frostless heat pump having thermal expansion valves

    DOE Patents [OSTI]

    Chen, Fang C. (Knoxville, TN); Mei, Viung C. (Oak Ridge, TN)

    2002-10-22T23:59:59.000Z

    A heat pump system having an operable relationship for transferring heat between an exterior atmosphere and an interior atmosphere via a fluid refrigerant and further having a compressor, an interior heat exchanger, an exterior heat exchanger, a heat pump reversing valve, an accumulator, a thermal expansion valve having a remote sensing bulb disposed in heat transferable contact with the refrigerant piping section between said accumulator and said reversing valve, an outdoor temperature sensor, and a first means for heating said remote sensing bulb in response to said outdoor temperature sensor thereby opening said thermal expansion valve to raise suction pressure in order to mitigate defrosting of said exterior heat exchanger wherein said heat pump continues to operate in a heating mode.

  5. Ultralow thermal conductivity and the thermal d t f i t fconductance of interfaces

    E-Print Network [OSTI]

    Braun, Paul

    are critical at the nanoscale · Low thermal conductivity in nanostructured materials ­ improved thermoelectric to the thermal conductivity of materials. · Ultralow thermal conductivity: beating the amorphous limitUltralow thermal conductivity and the thermal d t f i t fconductance of interfaces David G. Cahill

  6. Reduction of thermal conductivity of anharmonic lattices Lei Wang1 and Baowen Li1,2,3,

    E-Print Network [OSTI]

    Li, Baowen

    for constructing a material with ultra low thermal conductivity is still not available. As a simple. INTRODUCTION Thermal conductivity is one of the most fundamental and important properties of materials.1 heat dissipation. In the former case, one needs to have a very low thermal conductivity, while

  7. CONDUCTION HEAT TRANSFER Dr. Ruhul Amin Fall 2011

    E-Print Network [OSTI]

    Dyer, Bill

    ME 525 CONDUCTION HEAT TRANSFER Dr. Ruhul Amin Fall 2011 Office: 201C Roberts Hall Lecture Room of conduction heat transfer. Important results which are useful for engineering application will also: 121 Roberts Hall Phone: 994-6295 Lecture Periods: 12:45- 2:00, TR TEXT: Heat Conduction, M. N. Ozisik

  8. Ultralow Thermal Conductivity of Isotope-Doped Silicon Nanowires

    E-Print Network [OSTI]

    Li, Baowen

    conductivity of SiNWs is about 2 orders of magnitude smaller than that of bulk crystals.18,19 The low thermal conductivity (0.05 W/m K) found in layered materials.22 So it is indispensable to reduce the thermal conUltralow Thermal Conductivity of Isotope-Doped Silicon Nanowires Nuo Yang, Gang Zhang,*, and Baowen

  9. Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes

    E-Print Network [OSTI]

    candidates for thermoelectric materials as they can provide extremely low thermal conductivity , relatively of boundary scattering on the thermal conductivity. We show that the material porosity strongly affects1 Monte Carlo Simulations of Thermal Conductivity in Nanoporous Si Membranes Stefanie Wolf1

  10. Pushing the boundaries of the thermal conductivity of materials

    E-Print Network [OSTI]

    Braun, Paul

    Pushing the boundaries of the thermal conductivity of materials David G. Cahill, C. Chiritescu, Y. · Advances in time-domain thermoreflectance. · Amorphous limit to the thermal conductivity of materials. #12;50 nm Interfaces are critical at the nanoscale · Low thermal conductivity in nanostructured

  11. Note: Local thermal conductivities from boundary driven non-equilibrium molecular dynamics simulations

    SciTech Connect (OSTI)

    Bresme, F., E-mail: f.bresme@imperial.ac.uk [Department of Chemistry, Chemical Physics Section, Imperial College London, London SW7 2AZ (United Kingdom); Department of Chemistry, Norwegian University of Science and Technology, Trondheim (Norway); Armstrong, J., E-mail: j.armstrong@imperial.ac.uk [Department of Chemistry, Chemical Physics Section, Imperial College London, London SW7 2AZ (United Kingdom)

    2014-01-07T23:59:59.000Z

    We report non-equilibrium molecular dynamics simulations of heat transport in models of molecular fluids. We show that the “local” thermal conductivities obtained from non-equilibrium molecular dynamics simulations agree within numerical accuracy with equilibrium Green-Kubo computations. Our results support the local equilibrium hypothesis for transport properties. We show how to use the local dependence of the thermal gradients to quantify the thermal conductivity of molecular fluids for a wide range of thermodynamic states using a single simulation.

  12. Optimization of the configuration and working fluid for a micro heat pipe thermal control device

    E-Print Network [OSTI]

    Coughlin, Scott Joseph

    2006-04-12T23:59:59.000Z

    of a micro heat pipe system containing a working fluid with physical properties having been speciffcally selected such that the heat pipes, as a whole, vary in effective thermal conductance, thereby providing a level of temperature regulation...

  13. Heat recovery and thermal storage : a study of the Massachusetts State Transportation Building

    E-Print Network [OSTI]

    Bjorklund, Abbe Ellen

    1986-01-01T23:59:59.000Z

    A study of the energy system at the Massachusetts State Transportation Building was conducted. This innovative energy system utilizes internal-source heat pumps and a water thermal storage system to provide building heating ...

  14. Project Profile: Sensible Heat, Direct, Dual-Media Thermal Energy...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Sensible Heat, Direct, Dual-Media Thermal Energy Storage Module Project Profile: Sensible Heat, Direct, Dual-Media Thermal Energy Storage Module Acciona logo Acciona Solar, under...

  15. The thermal conductivity of rock under hydrothermal conditions: measurements and applications

    SciTech Connect (OSTI)

    Williams, Colin F.; Sass, John H.

    1996-01-24T23:59:59.000Z

    The thermal conductivities of most major rock-forming minerals vary with both temperature and confining pressure, leading to substantial changes in the thermal properties of some rocks at the high temperatures characteristic of geothermal systems. In areas with large geothermal gradients, the successful use of near-surface heat flow measurements to predict temperatures at depth depends upon accurate corrections for varying thermal conductivity. Previous measurements of the thermal conductivity of dry rock samples as a function of temperature were inadequate for porous rocks and susceptible to thermal cracking effects in nonporous rocks. We have developed an instrument for measuring the thermal conductivity of water-saturated rocks at temperatures from 20 to 350 °C and confining pressures up to 100 MPa. A transient line-source of heat is applied through a needle probe centered within the rock sample, which in turn is enclosed within a heated pressure vessel with independent controls on pore and confining pressure. Application of this technique to samples of Franciscan graywacke from The Geysers reveals a significant change in thermal conductivity with temperature. At reservoir-equivalent temperatures of 250 °C, the conductivity of the graywacke decreases by approximately 25% relative to the room temperature value. Where heat flow is constant with depth within the caprock overlying the reservoir, this reduction in conductivity with temperature leads to a corresponding increase in the geothermal gradient. Consequently, reservoir temperature are encountered at depths significantly shallower than those predicted by assuming a constant temperature gradient with depth. We have derived general equations for estimating the thermal conductivity of most metamorphic and igneous rocks and some sedimentary rocks at elevated temperature from knowledge of the room temperature thermal conductivity. Application of these equations to geothermal exploration should improve estimates of subsurface temperatures derived from heat flow measurements.

  16. G-Plus report to Owens Corning-thermal conductivity Measurements of Fiberglass

    SciTech Connect (OSTI)

    Wang, H

    2003-04-15T23:59:59.000Z

    Fiberglass made by Owens Corning is being used in noise reduction of automobile exhaust system. Specifically, the glass fibers are packed inside the muffler to achieve the desired acoustic effect. A secondary benefit of the fibers is to serve as a thermal insulation. Because of this insulating property, the glass fibers can serve to reduce the temperature of the muffler shell. This in turn reduces the need for heat shields around mufflers and reduces the amount of exterior temperature accelerated corrosion of the muffler shell, especially in the winter ''salt belts'' where large amounts of salt are placed on highways to minimize the safety impact of snow and ice. In addition, for some applications the use of the fiberglass could allow the use of lighter weight carbon based polymer composite materials in place of steel for muffler shells. However, in order to properly design exhaust systems without heat shields or to take advantage of new materials, the thermal conductivity of the fiberglass material at operating temperatures (for some applications above 750 C) must be known. We selected two types of Owens Corning glass fibers, 17 {micro}m and 24 {micro}m in diameter, for this study. There are some room temperature thermal conductivity data for the fiberglass, but high temperature data are not available. Based on the thermal radiation model, thermal conductivity should increase rapidly at high temperature, providing less thermal insulation. In addition, thermal conductivity depends on packing density of the glass fibers. We will study the effect of packing density on thermal conductivity. Another issue is that the glass fiber conducts heat better along the fiber, while the conduction across the fibers is poor, because thermal conduction from one fiber to another has to go through an interface with thermal resistance. In fiberglass, most fibers are not in good contact with the surrounding fibers, thus, most heat transfer is dependent on the thermal radiation effect. Among the many methods of measuring thermal conductivity, only a few can be used for glass fibers. The traditional heat flow meter is used in testing thermal insulations near room temperature. At higher temperatures this method cannot be used due to material and instrument limitations. Our plan is to use a transient plane source (TPS) method to measure thermal conductivity directly. The advantage of the TPS method is that measurements can be taken at over 700 C, and covers the temperature of the automobile exhausts. The following is a report for the G-Plus project conducted at ORNL to apply the TPS method to characterizing the thermal conductivity of two types of fiberglass and also the effect of packing density.

  17. Experimental investigation of the thermal conductivity of porous adsorbents. Master's thesis

    SciTech Connect (OSTI)

    Secary, J.J.

    1989-01-01T23:59:59.000Z

    The thermal conductivities of Praseodymium-Cerium-Oxide (PCO) and Saran Carbon have been experimentally investigated using a steady-state heat transfer technique. The investigated substances are used as adsorbents in adsorption compressors being developed for spaceborne refrigeration applications. The objectives of the investigation were to determine the thermal conductivities and establish their temperature dependency. Data were collected for the PCO over a temperature range of 300 C to 600 C, and O (zero) C to 200 C for the Saran Carbon. The thermal conductivities were found to have a strong temperature dependency. In particular, the results for the PCO showed a temperature dependency indicative of some thermal radiation effects.

  18. SENSIBLE HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT

    E-Print Network [OSTI]

    Baldwin, Thomas F.

    2011-01-01T23:59:59.000Z

    HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT Thomas F.CENTRAL RECEIVER SOLAR THERMAL POWER SYSTEM, PHASE progressCorporation, RECEIVER SOLAR THERMAL POWER SYSTEM, PHASE I,

  19. Molecular Dynamics Simulations of Heat Conduction in Nanostructures: Effect of Heat Bath

    E-Print Network [OSTI]

    Li, Baowen

    temperature profile and thermal conductivity in homogeneous materials. Furthermore, the thermal rectification) The low thermal conductivity of SiNWs is of particular interest for thermoelectric application.10 point of view. On the one hand, superior thermal conductivity has been observed in graphene1

  20. Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites

    SciTech Connect (OSTI)

    Liu, Ying [Clemson University] [Clemson University; Huang, Jingsong [ORNL] [ORNL; Yang, Bao [University of Maryland] [University of Maryland; Sumpter, Bobby G [ORNL] [ORNL; Qiao, Rui [Clemson University] [Clemson University

    2014-01-01T23:59:59.000Z

    The thermal conductance of graphene-matrix interfaces plays a key role in controlling the thermal transport properties of graphene-based nanocomposites. Using classical molecular dynamics simulations, we found that the interfacial thermal conductance depends strongly on the mode of heat transfer at the graphene-matrix interfaces: if heat enters graphene from one side of its basal plane and immediately leaves the graphene through the other side, the corresponding interfacial thermal conductance, G(across), is large; if heat enters graphene from both sides of its basal plane and leaves the graphene at a position far away on its basal plane, the corresponding interfacial thermal conductance, G(non-across), is small. For a single-layer graphene immersed in liquid octane, G(across) is ~150 MW/m2K while Gnon-across is ~5 MW/m2K. G(across) decreases with increasing multi-layer graphene thickness (i.e., number of layers in graphene) and approaches an asymptotic value of 100 MW/m2K for 7-layer graphenes. G(non-across) increases only marginally as the graphene sheet thickness increases. Such a duality of the interface thermal conductance for different probing methods and its dependence on graphene sheet thickness can be traced ultimately to the unique physical and chemical structure of graphene materials. The ramifications of these results in areas such as experimental measurement of thermal conductivity of graphene and the design of graphene-based thermal nanocomposites are discussed.

  1. THERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND

    E-Print Network [OSTI]

    envelope and on the performance of systems. This behaviour is related to hygric and thermal propertiesTHERMAL CONDUCTIVITY OF HEMP CONCRETES: VARIATION WITH FORMULATION, DENSITY AND WATER CONTENT of formulation, density and water content on the thermal conductivity of hemp concretes. The investigations

  2. Morphology and thermal conductivity of yttria-stabilized zirconia coatings

    E-Print Network [OSTI]

    Wadley, Haydn

    yttria-stabilized zir- conia (YSZ) is then applied to provide thermal insulation [1]. This ceramic layer]. The thermal conductivity of the ceramic layer has been found to depend on the pore morphology within a coatingMorphology and thermal conductivity of yttria-stabilized zirconia coatings Hengbei Zhao a

  3. Thermal Conductivity of Polycrystalline Semiconductors and Ceramics

    E-Print Network [OSTI]

    Wang, Zhaojie

    2012-01-01T23:59:59.000Z

    Brown, C. M. ; Zhang, Q. ; Tritt, T. M. Nano Letters 2010,Monteiro, O. Microelectronics journal Tritt, T. M. , Thermal

  4. Effective thermal conductivity for anisotropic granular porous media using fractal concepts

    SciTech Connect (OSTI)

    Sabau, A.S.; Tao, Y.X.; Liu, G.; Vidhuvalavan, G.

    1997-07-01T23:59:59.000Z

    The use of granular porous media in chemical processes, thermal insulation, heat exchangers, and nuclear reactor fuel rods has led to the development of correlations for thermophysical properties, such as thermal conductivity. These correlations are essential in the prediction of heat and mass transfer involving porous media. Analytical correlations are derived for the effective thermal conductivity of anisotropic, Granular Porous Media (GPM). The correlations proposed, which can be apply in general to any porous media material, are used to determine the effective thermal conductivity of GPM that are formed by semi-cylindrical ice particles. Pictures of the cross-section of GPM provide digital data for measuring local fractal dimensions. Local fractal dimensions are used to determine an equivalent three-dimensional Representative Unit Cell (RUC) for the GPM considered. A simplified analysis of heat conduction at the RUC level provide an analytical expression for the effective heat transfer coefficient. Estimates for the effective thermal conductivity by the use of the models are discussed and compared with various models known in literature. Finally, results for anisotropic thermal conductivities, which are obtained by the use of fractal correlations, are discussed.

  5. Thermal conductivity of graphene nanoribbons in noble gaseous environments

    SciTech Connect (OSTI)

    Zhong, Wei-Rong, E-mail: wrzhong@hotmail.com; Xu, Zhi-Cheng; Zheng, Dong-Qin [Department of Physics and Siyuan Laboratory, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Ai, Bao-Quan, E-mail: aibq@scnu.edu.cn [Laboratory of Quantum Information Technology, ICMP and SPTE, South China Normal University, Guangzhou 510006 (China)

    2014-02-24T23:59:59.000Z

    We investigate the thermal conductivity of suspended graphene nanoribbons in noble gaseous environments using molecular dynamics simulations. It is reported that the thermal conductivity of perfect graphene nanoribbons decreases with the gaseous pressure. The decreasing is more obvious for the noble gas with large atomic number. However, the gaseous pressure cannot change the thermal conductivity of defective graphene nanoribbons apparently. The phonon spectra of graphene nanoribbons are also provided to give corresponding supports.

  6. Estimation of composite thermal conductivity of a heterogeneous methane hydrate sample using iTOUGH2

    E-Print Network [OSTI]

    Gupta, Arvind; Kneafsey, Timothy J.; Moridis, George J.; Seol, Yongkoo; Kowalsky, Michael B.; Sloan Jr., E.D.

    2006-01-01T23:59:59.000Z

    15–17, 2006 ESTIMATION OF COMPOSITE THERMAL CONDUCTIVITY OFABSTRACT We determined the composite thermal conductivity (kfrom granular ice. The composite thermal conductivity was

  7. EFFECTIVE THERMAL CONDUCTIVITY OF LITHIUM CERAMIC PEBBLE BEDS FOR FUSION BLANKETS: A REVIEW

    E-Print Network [OSTI]

    Abdou, Mohamed

    a significant interest as solid breeders for the fusion blankets during the last three decades. The solid for the fusion solid breeder blankets. In order to study the heat transfer in the blanket, effective conductivityEFFECTIVE THERMAL CONDUCTIVITY OF LITHIUM CERAMIC PEBBLE BEDS FOR FUSION BLANKETS: A REVIEW A. ABOU

  8. Electrical and thermal conductivity of low temperature CVD graphene...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and thermal conductivity of low temperature CVD graphene: the effect of disorder This article has been downloaded from IOPscience. Please scroll down to see the full text article....

  9. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOE Patents [OSTI]

    Christensen, C.B.; Kutscher, C.F.; Gawlik, K.M.

    1997-12-02T23:59:59.000Z

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprises an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution. 3 figs.

  10. Unglazed transpired solar collector having a low thermal-conductance absorber

    DOE Patents [OSTI]

    Christensen, Craig B. (Boulder, CO); Kutscher, Charles F. (Golden, CO); Gawlik, Keith M. (Boulder, CO)

    1997-01-01T23:59:59.000Z

    An unglazed transpired solar collector using solar radiation to heat incoming air for distribution, comprising an unglazed absorber formed of low thermal-conductance material having a front surface for receiving the solar radiation and openings in the unglazed absorber for passage of the incoming air such that the incoming air is heated as it passes towards the front surface of the absorber and the heated air passes through the openings in the absorber for distribution.

  11. Effects of Thermal Conductivity Ratio in

    E-Print Network [OSTI]

    Single jet-impingement design Dimensions similar to HEMP Constructed of C36000 brass alloy Heated on HEMP design at 10 MW/m2 Re = 7.6104 at central port Experiments: 1104

  12. MOLECULAR DYNAMICS SIMULATION OF THERMAL BOUNDARY CONDUCTANCE BETWEEN SWNT AND

    E-Print Network [OSTI]

    Maruyama, Shigeo

    MOLECULAR DYNAMICS SIMULATION OF THERMAL BOUNDARY CONDUCTANCE BETWEEN SWNT AND SURROUNDING FLUIDS JinHyeok Cha, Shohei Chiashi, Junichiro Shiomi, and Shigeo Maruyama* Department of Mechanical applications. In particular, the thermal boundary conductance (TBC) K between an SWNT and surrounding fluid

  13. Value of solar thermal industrial process heat

    SciTech Connect (OSTI)

    Brown, D.R.; Fassbender, L.L.; Chockie, A.D.

    1986-03-01T23:59:59.000Z

    This study estimated the value of solar thermal-generated industrial process heat (IPH) as a function of process heat temperature. The value of solar thermal energy is equal to the cost of producing energy from conventional fuels and equipment if the energy produced from either source provides an equal level of service. This requirement put the focus of this study on defining and characterizing conventional process heat equipment and fuels. Costs (values) were estimated for 17 different design points representing different combinations of conventional technologies, temperatures, and fuels. Costs were first estimated for median or representative conditions at each design point. The cost impact of capacity factor, efficiency, fuel escalation rate, and regional fuel price differences were then evaluated by varying each of these factors within credible ranges.

  14. FAST STATIC AND DYNAMIC GRID LEVEL THERMAL SIMULATION CONSIDERING TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF SILICON

    E-Print Network [OSTI]

    Ziabari, Amirkoushyar

    2012-01-01T23:59:59.000Z

    heat diffusion equation has been conventionally handled by grid-grids and an approximate delta function simulating a point heatgrid size of 64×64. To obtain transient thermal mask an impulse heat

  15. Composite material having high thermal conductivity and process for fabricating same

    DOE Patents [OSTI]

    Colella, N.J.; Davidson, H.L.; Kerns, J.A.; Makowiecki, D.M.

    1998-07-21T23:59:59.000Z

    A process is disclosed for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost. 7 figs.

  16. Composite material having high thermal conductivity and process for fabricating same

    DOE Patents [OSTI]

    Colella, Nicholas J. (Livermore, CA); Davidson, Howard L. (San Carlos, CA); Kerns, John A. (Livermore, CA); Makowiecki, Daniel M. (Livermore, CA)

    1998-01-01T23:59:59.000Z

    A process for fabricating a composite material such as that having high thermal conductivity and having specific application as a heat sink or heat spreader for high density integrated circuits. The composite material produced by this process has a thermal conductivity between that of diamond and copper, and basically consists of coated diamond particles dispersed in a high conductivity metal, such as copper. The composite material can be fabricated in small or relatively large sizes using inexpensive materials. The process basically consists, for example, of sputter coating diamond powder with several elements, including a carbide forming element and a brazeable material, compacting them into a porous body, and infiltrating the porous body with a suitable braze material, such as copper-silver alloy, thereby producing a dense diamond-copper composite material with a thermal conductivity comparable to synthetic diamond films at a fraction of the cost.

  17. Conductive Thermal Interaction in Evaporative Cooling Process

    E-Print Network [OSTI]

    Kim, B. S.; Degelman, L. O.

    1990-01-01T23:59:59.000Z

    be considered. Usually the dry-bulb depression performed by an evaporative cooler depends solely on the ambient wet-bulb temperature. The cool underground water in an evaporative cooler can cause not only adiabatic evaporation but also sensible heat transfer...

  18. Advanced Heat Transfer Fluids and Novel Thermal Storage Concepts...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Systems Lehigh University: Novel Thermal Storage Technologies for Concentrating Solar Power Generation Terrafore: Heat Transfer and Latent Heat Storage in Inorganic Molten...

  19. Effect of Aggregation on Thermal Conduction in Colloidal Nanofluids

    SciTech Connect (OSTI)

    R Prasher; W Evans; J Fish; P Meakin; P Phelan; Pawel Keblinski

    2006-08-10T23:59:59.000Z

    Using effective medium theory we demonstrate that the thermal conductivity of nanofluids can be significantly enhanced by the aggregation of nanoparticles into clusters. The enhancement is based purely on conduction and does not require a novel mechanism. Predictions of the effective medium theory are in excellent agreement with detailed numerical calculations on model nanofluids involving fractal clusters and show the importance of cluster morphology on thermal conductivity enhancements.

  20. Glass-Like Heat Conduction in Crystalline Semiconductors

    SciTech Connect (OSTI)

    Nolas, G.S.; Cohn, J.L.; Chakoumakos, B.C.; Slack, G.A.

    1999-06-13T23:59:59.000Z

    The thermal conductivity and structural properties of polycrystalline and single crystal semiconductor type-1 germanium clathrates are reported. Germanium clathrates exhibit thermal conductivities that are typical of amorphous materials. This behavior occurs in spite of their well-defined crystalline structure. The authors employ temperature dependent neutron diffraction data in investigating the displacements of the caged strontium atoms in Sr{sub 8}Ga{sub 16}Ge{sub 30} and their interaction with the polyhedral cages that entrap them. Their aim is to investigate the correlation between the structural properties and the low, glass-like thermal conductivity observed in this compound.

  1. Thermal conductivity of beryllium-gas packed bed

    SciTech Connect (OSTI)

    Xu, M.; Abdou, M.A.; Raffray, A.R. [Univ. of California, Los Angeles, CA (United States)

    1994-12-31T23:59:59.000Z

    Unsintered packed bed has been suggested as a material form for solid breeder and multiplier in the ITER and fusion power reactor blankets. Study of the effective bed thermal conductivity can provide tools for analysis of the blanket performance under different operating conditions, and of how to actively control the thermal behavior of the blanket. Issues of particular interest are the ability to predict and to control the thermal conductivity. The 2-D model developed at UCLA is used to study the effect of particle diameter, solid-to-gas conductivity ratio, bed porosity, contact area, and surface roughness characteristics on bed thermal conductivity. The study shows that all parameters except bed porosity play important roles in determining the bed thermal controllability.

  2. Thermal Storage and Advanced Heat Transfer Fluids (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2010-08-01T23:59:59.000Z

    Fact sheet describing NREL CSP Program capabilities in the area of thermal storage and advanced heat transfer fluids: measuring thermophysical properties, measuring fluid flow and heat transfer, and simulating flow of thermal energy and fluid.

  3. Firearm suppressor having enhanced thermal management for rapid heat dissipation

    DOE Patents [OSTI]

    Moss, William C.; Anderson, Andrew T.

    2014-08-19T23:59:59.000Z

    A suppressor is disclosed for use with a weapon having a barrel through which a bullet is fired. The suppressor has an inner portion having a bore extending coaxially therethrough. The inner portion is adapted to be secured to a distal end of the barrel. A plurality of axial flow segments project radially from the inner portion and form axial flow paths through which expanding propellant gasses discharged from the barrel flow through. The axial flow segments have radially extending wall portions that define sections which may be filled with thermally conductive material, which in one example is a thermally conductive foam. The conductive foam helps to dissipate heat deposited within the suppressor during firing of the weapon.

  4. Computational Efficient Upscaling Methodology for Predicting Thermal Conductivity of Nuclear Waste forms

    SciTech Connect (OSTI)

    Li, Dongsheng; Sun, Xin; Khaleel, Mohammad A.

    2011-09-28T23:59:59.000Z

    This study evaluated different upscaling methods to predict thermal conductivity in loaded nuclear waste form, a heterogeneous material system. The efficiency and accuracy of these methods were compared. Thermal conductivity in loaded nuclear waste form is an important property specific to scientific researchers, in waste form Integrated performance and safety code (IPSC). The effective thermal conductivity obtained from microstructure information and local thermal conductivity of different components is critical in predicting the life and performance of waste form during storage. How the heat generated during storage is directly related to thermal conductivity, which in turn determining the mechanical deformation behavior, corrosion resistance and aging performance. Several methods, including the Taylor model, Sachs model, self-consistent model, and statistical upscaling models were developed and implemented. Due to the absence of experimental data, prediction results from finite element method (FEM) were used as reference to determine the accuracy of different upscaling models. Micrographs from different loading of nuclear waste were used in the prediction of thermal conductivity. Prediction results demonstrated that in term of efficiency, boundary models (Taylor and Sachs model) are better than self consistent model, statistical upscaling method and FEM. Balancing the computation resource and accuracy, statistical upscaling is a computational efficient method in predicting effective thermal conductivity for nuclear waste form.

  5. Lattice thermal conductivity of UO{sub 2} using ab-initio and classical molecular dynamics

    SciTech Connect (OSTI)

    Kim, Hyoungchul [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); High-Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136–791 (Korea, Republic of); Kim, Moo Hwan [Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Kaviany, Massoud, E-mail: kaviany@umich.edu [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Division of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of)

    2014-03-28T23:59:59.000Z

    We applied the non-equilibrium ab-initio molecular dynamics and predict the lattice thermal conductivity of the pristine uranium dioxide for up to 2000?K. We also use the equilibrium classical molecular dynamics and heat-current autocorrelation decay theory to decompose the lattice thermal conductivity into acoustic and optical components. The predicted optical phonon transport is temperature independent and small, while the acoustic component follows the Slack relation and is in good agreement with the limited single-crystal experimental results. Considering the phonon grain-boundary and pore scatterings, the effective lattice thermal conductivity is reduced, and we show it is in general agreement with the sintered-powder experimental results. The charge and photon thermal conductivities are also addressed, and we find small roles for electron, surface polaron, and photon in the defect-free structures and for temperatures below 1500?K.

  6. Odne Stokke Burheim Thermal Signature and Thermal Conductivities of PEM Fuel Cells

    E-Print Network [OSTI]

    Kjelstrup, Signe

    Odne Stokke Burheim Thermal Signature and Thermal Conductivities of PEM Fuel Cells Thesis-Holst for believing in me and for giving me the opportunity to join the work on the "Thermal Effects in Fuel cell The work presented here gives estimates on thermal gradients within the PEM fuel cell, an experimental

  7. An Analytical Study Of A 2-Layer Transient Thermal Conduction...

    Open Energy Info (EERE)

    Study Of A 2-Layer Transient Thermal Conduction Problem As Applied To Soil-Temperature Surveys Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article:...

  8. A benchmark study on the thermal conductivity of nanofluids

    E-Print Network [OSTI]

    Buongiorno, Jacopo

    This article reports on the International Nanofluid Property Benchmark Exercise, or INPBE, in which the thermal conductivity of identical samples of colloidally stable dispersions of nanoparticles or “nanofluids,” was ...

  9. Investigation on thermal conductivity and AC impedance of graphite suspension

    E-Print Network [OSTI]

    Wang, Jianjian, S.M. Massachusetts Institute of Technology

    2011-01-01T23:59:59.000Z

    Over the past decade, some groups have reported that nanofluids, which are liquids containing suspensions of nanoparticles, have substantially higher thermal conductivity than that of the base fluids. However, the reported ...

  10. Resonant bonding leads to low lattice thermal conductivity

    E-Print Network [OSTI]

    Lee, Sangyeop

    Understanding the lattice dynamics and low thermal conductivities of IV–VI, V[subscript 2]–VI[subscript 3] and V materials is critical to the development of better thermoelectric and phase-change materials. Here we provide ...

  11. The thermal conductivity of sediments as a function of porosity

    E-Print Network [OSTI]

    Miller, James W

    1979-01-01T23:59:59.000Z

    1979 Major Subject: Civil Engineering THE THERMAL CONDUCTIVITY OF SEDIMENTS AS A FUNCTION OF POROSITY A Thesis by JAMES WARREN MILLER Approved as to style and content by: Louis J. hompson CE)(Chairman of Committee) Harry M. Coyle (CE)( ember...THE THERMAL CONDUCTIVITY OF SEDIMENTS AS A FUNCTION OF POROSITY A Thesis by JAMES WARREN MILLER Submitted to the Graduate College of Texas AAM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August...

  12. Modeling the thermal conductivity of fiber-reinforced ceramic composites

    SciTech Connect (OSTI)

    Beecher, S.C.; Dinwiddie, R.B.

    1993-06-01T23:59:59.000Z

    A review of models for the prediction of the thermal conductivity of uni-directional fiber-reinforced composites will be presented. The ability of these models to give an accurate prediction of the composite thermal conductivity depends on the amount of information known about the constituent phase properties under the assumption that these properties do not change as a result of processing. Also presented are models that take into account the effects of fiber coatings.

  13. Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities

    E-Print Network [OSTI]

    Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D.

    2012-01-01T23:59:59.000Z

    is underestimated. For picolitre droplets however, convective heat transfer due to internal flows is negligible compared to conduc- tion. The relative effect of convection and conduction is seen in the Pe´clet number, Pe = uR/K, where K is the thermal diffusivity...

  14. Thermal Conductivity Spectroscopy Technique to Measure Phonon Mean Free Paths

    E-Print Network [OSTI]

    Schmidt, A. J.

    Size effects in heat conduction, which occur when phonon mean free paths (MFPs) are comparable to characteristic lengths, are being extensively explored in many nanoscale systems for energy applications. Knowledge of MFPs ...

  15. Serpentine Thermal Coupling Between a Stream and a Conducting Body

    SciTech Connect (OSTI)

    Kobayashi, H.; Lorente, S.; Anderson, R.; Bejan, A.

    2012-02-15T23:59:59.000Z

    Here we document the effect of flow configuration on the heat transfer performance of a serpentine shaped stream embedded in a conducting solid. Several configurations with fixed volume of fluid are considered: U-shaped with varying spacing between the parallel portions of the U, serpentine shapes with three elbows, and conducting soil with several parallelepipedal shapes. We show that the spacing must be greater than a critical value in order for the heat transfer density of the stream-solid configuration to be the highest that it can be. Spacings larger than this critical value do not yield improvements in heat transfer density. We also show that even though the heat transfer is time dependent, the stream-solid configuration has an effective number of heat transfer units Ntu that is nearly constant in time. The larger Ntu values correspond to the configurations with greater heat transfer density.

  16. Single-photon heat conduction in electrical circuits

    E-Print Network [OSTI]

    Jones, P J; Tan, K Y; Möttönen, M

    2011-01-01T23:59:59.000Z

    We study photonic heat conduction between two resistors coupled weakly to a single superconducting microwave cavity. At low enough temperature, the dominating part of the heat exchanged between the resistors is transmitted by single-photon excitations of the fundamental mode of the cavity. This manifestation of single-photon heat conduction should be experimentally observable with the current state of the art. Our scheme can possibly be utilized in remote interference-free temperature control of electric components and environment engineering for superconducting qubits coupled to cavities.

  17. Single-photon heat conduction in electrical circuits

    E-Print Network [OSTI]

    P. J. Jones; J. A. M. Huhtamäki; K. Y. Tan; M. Möttönen

    2011-07-14T23:59:59.000Z

    We study photonic heat conduction between two resistors coupled weakly to a single superconducting microwave cavity. At low enough temperature, the dominating part of the heat exchanged between the resistors is transmitted by single-photon excitations of the fundamental mode of the cavity. This manifestation of single-photon heat conduction should be experimentally observable with the current state of the art. Our scheme can possibly be utilized in remote interference-free temperature control of electric components and environment engineering for superconducting qubits coupled to cavities.

  18. Thermal conductivity profile determination in proton-irradiated ZrC by spatial and frequency scanning thermal wave methods

    SciTech Connect (OSTI)

    Jensen, C. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France) [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States); Chirtoc, M.; Horny, N.; Antoniow, J. S.; Pron, H. [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France)] [GRESPI, Multiscale Thermophysics Lab., Université de Reims Champagne-Ardenne URCA, Moulin de la Housse BP 1039, Reims 51687 (France); Ban, H. [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)] [Department of Mechanical and Aerospace Engineering, Utah State University, Logan, Utah 84322 (United States)

    2013-10-07T23:59:59.000Z

    Using complementary thermal wave methods, the irradiation damaged region of zirconium carbide (ZrC) is characterized by quantifiably profiling the thermophysical property degradation. The ZrC sample was irradiated by a 2.6 MeV proton beam at 600 °C to a dose of 1.75 displacements per atom. Spatial scanning techniques including scanning thermal microscopy (SThM), lock-in infrared thermography (lock-in IRT), and photothermal radiometry (PTR) were used to directly map the in-depth profile of thermal conductivity on a cross section of the ZrC sample. The advantages and limitations of each system are discussed and compared, finding consistent results from all techniques. SThM provides the best resolution finding a very uniform thermal conductivity envelope in the damaged region measuring ?52 ± 2 ?m deep. Frequency-based scanning PTR provides quantification of the thermal parameters of the sample using the SThM measured profile to provide validation of a heating model. Measured irradiated and virgin thermal conductivities are found to be 11.9 ± 0.5 W m{sup ?1} K{sup ?1} and 26.7 ±1 W m{sup ?1} K{sup ?1}, respectively. A thermal resistance evidenced in the frequency spectra of the PTR results was calculated to be (1.58 ± 0.1) × 10{sup ?6} m{sup 2} K W{sup ?1}. The measured thermal conductivity values compare well with the thermal conductivity extracted from the SThM calibrated signal and the spatially scanned PTR. Combined spatial and frequency scanning techniques are shown to provide a valuable, complementary combination for thermal property characterization of proton-irradiated ZrC. Such methodology could be useful for other studies of ion-irradiated materials.

  19. Metallic coatings for enhancement of thermal contact conductance

    SciTech Connect (OSTI)

    Lambert, M.A.; Fletcher, L.S. (Texas A M Univ., College Station, TX (United States))

    1994-04-01T23:59:59.000Z

    The reliability of standard electronic modules may be improved by decreasing overall module temperature. This may be accomplished by enhancing the thermal contact conductance at the interface between the module frame guide rib and the card rail to which the module is clamped. Some metallic coatings, when applied to the card rail, would deform under load, increasing the contact area and associated conductance. This investigation evaluates the enhancements in thermal conductance afforded by vapor deposited silver and gold coatings. Experimental thermal conductance measurements were made for anodized aluminum 6101-T6 and electroless nickel-plated copper C11000-H03 card materials to the aluminum A356-T61 rail material. Conductance values for the electroless nickel-plated copper junction ranged from 600 to 2800 W/m(exp 2)K and those for the anodized aluminum junction ranged from 25 to 91 W/m(exp 2)K for contact pressures of 0.172-0.862 MPa and mean junction temperatures of 20-100 C. Experimental thermal conductance values of vapor deposited silver- and gold-coated aluminum A356-T61 rail surfaces indicate thermal enhancements of 1.25-2.19 for the electroless nickel-plated copper junctions and 1.79-3.41 for the anodized aluminum junctions. The silver and gold coatings provide significant thermal enhancement; however, these coating-substrate combinations are susceptible to galvanic corrosion under some conditions. 25 refs.

  20. October 2011 SDI FEP Issues Heat Conduction Issues (HC)

    E-Print Network [OSTI]

    a thermal dam and EPA is looking for information to address the issue. Heat Effects on Host Rock Properties (HRP) Clay Seams SDI-(HRP) -1 What are the expected effects of a 300o C temperature source on the clay source on the anhydrite layer properties? Background: There has been significant effort to incorporate

  1. Effective Thermal Conductivity of Lithium Ceramic Pebble Beds for Fusion Blankets: A Review

    SciTech Connect (OSTI)

    Abou-Sena, A.; Ying, A.; Abdou, M. [University of California, Los Angeles (United States)

    2005-05-15T23:59:59.000Z

    The use of lithium ceramic pebble beds has been considered in many blanket designs for the fusion reactors. Lithium ceramics have received a significant interest as tritium breeders for the fusion blankets during the last three decades. The thermal performance of the lithium ceramic pebble beds plays a key role for the fusion blankets. In order to study the heat transfer in the blanket, the effective thermal conductivity of the lithium ceramics pebble beds has to be well measured and characterized. The data of effective thermal conductivity of lithium ceramic pebble beds is important for the blanket design. Several studies have been dedicated to investigate the effective conductivity of the lithium ceramics pebble beds. The objective of this work is to review and compare the available data, presented by various studies, of effective conductivity of lithium ceramic pebble beds in order to address the current status of these data.

  2. Author's personal copy Pyroelectric waste heat energy harvesting using heat conduction

    E-Print Network [OSTI]

    Pilon, Laurent

    -product of power, refrigeration, or heat pump cycles according to the second law of thermodynamics [1]. In 2009 pump, cryogenic refrigeration, and air liquefaction applications [3]. Organic Rankine cycles useAuthor's personal copy Pyroelectric waste heat energy harvesting using heat conduction Felix Y. Lee

  3. Temperature dependence of thermal conductivities of coupled rotator lattice and the momentum diffusion in standard map

    E-Print Network [OSTI]

    Yunyun Li; Nianbei Li; Baowen Li

    2015-01-29T23:59:59.000Z

    In contrary to other 1D momentum-conserving lattices such as the Fermi-Pasta-Ulam $\\beta$ (FPU-$\\beta$) lattice, the 1D coupled rotator lattice is a notable exception which conserves total momentum while exhibits normal heat conduction behavior. The temperature behavior of the thermal conductivities of 1D coupled rotator lattice had been studied in previous works trying to reveal the underlying physical mechanism for normal heat conduction. However, two different temperature behaviors of thermal conductivities have been claimed for the same coupled rotator lattice. These different temperature behaviors also intrigue the debate whether there is a phase transition of thermal conductivities as the function of temperature. In this work, we will revisit the temperature dependent thermal conductivities for the 1D coupled rotator lattice. We find that the temperature dependence follows a power law behavior which is different with the previously found temperature behaviors. Our results also support the claim that there is no phase transition for 1D coupled rotator lattice. We also give some discussion about the similarity of diffusion behaviors between the 1D coupled rotator lattice and the single kicked rotator also called the Chirikov standard map.

  4. Thermal response of a flat heat pipe sandwich structure to a localized heat flux

    E-Print Network [OSTI]

    Wadley, Haydn

    Thermal response of a flat heat pipe sandwich structure to a localized heat flux G. Carbajal a , C The temperature distribution across a flat heat pipe sandwich structure, subjected to an intense localized thermal to the evaporator side of the flat heat pipe, while the condenser side was cooled via natural convective

  5. Lattice thermal conductivity of nanograined half-Heusler solid solutions

    SciTech Connect (OSTI)

    Geng, Huiyuan, E-mail: genghuiyuan@hit.edu.cn; Meng, Xianfu; Zhang, Hao; Zhang, Jian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2014-05-19T23:59:59.000Z

    We report a phenomenological model of atomic weight, lattice constant, temperature, and grain size to calculate the high-temperature lattice thermal conductivity of nanograined solid solutions. The theoretical treatment developed here is reasonably consistent with the experimental results of n-type MNiSn and p-type MCoSb alloys, where M is the combination of Hf, Zr, and Ti. For disordered half-Heusler alloys with moderated grain sizes, we predict that the reduction in lattice thermal conductivity due to grain boundary scattering is independent of the scattering parameter, which characterizes the phonon scattering cross section of point defects. In addition, the lattice thermal conductivity falls off with temperature as T{sup –1?2} around the Debye temperature.

  6. Thermal conductivity of highly-ordered mesoporous titania thin films from 30 to 320 K

    E-Print Network [OSTI]

    2011-01-01T23:59:59.000Z

    Thermal resistance of grain boundaries in alumina ceramicsThermal conductivity of highly porous zirconia”. Journal of the European Ceramic

  7. High thermal conductivity lossy dielectric using a multi layer configuration

    DOE Patents [OSTI]

    Tiegs, Terry N. (Lenoir City, TN); Kiggans, Jr., James O. (Oak Ridge, TN)

    2003-01-01T23:59:59.000Z

    Systems and methods are described for loss dielectrics. A loss dielectric includes at least one high dielectric loss layer and at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. A method of manufacturing a loss dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. The systems and methods provide advantages because the loss dielectrics are less costly and more environmentally friendly than the available alternatives.

  8. Thermal conduction of SSC (Superconducting Super Collider) wire

    SciTech Connect (OSTI)

    Kuchnir, M.; Tague, J.L.

    1989-08-01T23:59:59.000Z

    A method suitable for measuring the thermal conductivity of good thermal conductors at low temperatures was implemented. It successfully served its purpose: to detect the effect of doping with manganese the interfilament part of the copper matrix of the superconducting wire used in the magnets of the Superconducting Super Collider. It uses two heaters and one thermometer per sample reducing the accuracy requirement on the thermometers, automatically compensating for zero offsets and reducing the number of critical thermal contacts. Commercially available strain gauges are used as heaters. 3 refs., 2 figs.

  9. Effects of neutron irradiation on thermal conductivity of SiC-based composites and monolithic ceramics

    SciTech Connect (OSTI)

    Senor, D.J.; Youngblood, G.E. [Pacific Northwest National Lab., Richland, WA (United States); Moore, C.E. [Auburn Univ., AL (United States); Trimble, D.J. [Westinghouse Hanford Co., Richland, WA (United States); Woods, J.J. [Lockheed Martin, Schenectady, NY (United States)

    1996-06-01T23:59:59.000Z

    A variety of SiC-based composites and monolithic ceramics were characterized by measuring their thermal diffusivity in the unirradiated, thermal annealed, and irradiated conditions over the temperature range 400 to 1,000 C. The irradiation was conducted in the EBR-II to doses of 33 and 43 dpa-SiC (185 EFPD) at a nominal temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. Thermal diffusivity was measured using the laser flash method, and was converted to thermal conductivity using density data and calculated specific heat values. Exposure to the 165 day anneal did not appreciably degrade the conductivity of the monolithic or particulate-reinforced composites, but the conductivity of the fiber-reinforced composites was slightly degraded. The crystalline SiC-based materials tested in this study exhibited thermal conductivity degradation of irradiation, presumably caused by the presence of irradiation-induced defects. Irradiation-induced conductivity degradation was greater at lower temperatures, and was typically more pronounced for materials with higher unirradiated conductivity. Annealing the irradiated specimens for one hour at 150 C above the irradiation temperature produced an increase in thermal conductivity, which is likely the result of interstitial-vacancy pair recombination. Multiple post-irradiation anneals on CVD {beta}-SiC indicated that a portion of the irradiation-induced damage was permanent. A possible explanation for this phenomenon was the formation of stable dislocation loops at the high irradiation temperature and/or high dose that prevented subsequent interstitial/vacancy recombination.

  10. Effects of neutron irradiation on thermal conductivity of SiC-based composites and monolithic ceramics

    SciTech Connect (OSTI)

    Senor, D.J.; Youngblood, G.E. [Pacific Northwest National Lab., Richland, WA (United States); Moore, C.E. [Auburn Univ., AL (United States); Trimble, D.J. [Westinghouse Hanford Co., Richland, WA (United States); Woods, J.J. [Lockheed Martin, Schenectady, NY (United States)

    1997-05-01T23:59:59.000Z

    A variety of SiC-based composites and monolithic ceramics were characterized by measuring their thermal diffusivity in the unirradiated, thermal annealed, and irradiated conditions over the temperature range 400 to 1,000 C. The irradiation was conducted in the EBR-II to doses of 33 and 43 dpa-SiC (185 EFPD) at a nominal temperature of 1,000 C. The annealed specimens were held at 1,010 C for 165 days to approximately duplicate the thermal exposure of the irradiated specimens. Thermal diffusivity was measured using the laser flash method, and was converted to thermal conductivity using density data and calculated specific heat values. Exposure to the 165 day anneal did not appreciably degrade the conductivity of the monolithic or particulate-reinforced composites, but the conductivity of the fiber-reinforced composites was slightly degraded. The crystalline SiC-based materials tested in this study exhibited thermal conductivity degradation after irradiation, presumably caused by the presence of irradiation-induced defects. Irradiation-induced conductivity degradation was greater at lower temperatures, and was typically more pronounced for materials with higher unirradiated conductivity. Annealing the irradiated specimens for one hour at 150 C above the irradiation temperature produced an increase in thermal conductivity, which is likely the result of interstitial-vacancy pair recombination. Multiple post-irradiation anneals on CVD {beta}-SiC indicated that a portion of the irradiation-induced damage was permanent. A possible explanation for this phenomenon was the formation of stable dislocation loops at the high irradiation temperature and/or high dose that prevented subsequent interstitial/vacancy recombination.

  11. The contact heat conductance at diamond-OFHC copper interface with GaIn eutectic as a heat transfer medium

    SciTech Connect (OSTI)

    Assoufid, L.; Khounsary, A.M.

    1996-01-01T23:59:59.000Z

    Results of an experimental study of the contact heat conductance across a single diamond crystal interface with OFHC copper (Cu) are reported. Gallium-indium (GaIn) eutectic was used as an interstitial material. Contact conductance data are important in the design and the prediction of the performance of x-ray diamond monochromators under high-heat-load conditions. Two sets of experiments were carried out. In one, the copper surface in contact with diamond was polished and then electroless plated with 1 {mu}m of nickel, while in the other, the copper contact surface was left as machined. Measured average interface heat conductances are 44.7 {plus_minus}8 W/cm{sup 2}{minus}K for nonplated copper and 23.0 {plus_minus}3 W/cm{sup 2}{minus}K for nickel-plated copper. For reference, the thermal contact conductances at a copper-copper interface (without diamond) were also measured, and the results are reported. A typical diamond monochromator, 0.2 mm thick, will absorb about 44 W under a standard undulator beam at the Advanced Photon Source. The measured conductance for nickel-plated copper suggests that the temperature drop across the interface of diamond and nickel-plated copper, with a 20 mm{sup 2} contact area, will be about 10{degree}C. Therefore temperature rises are rather modest, and the accuracy of the measured contact conductances presented here are sufficient for design purposes.

  12. Contact heat conductance at a diamond-OFHC copper interface with GaIn eutectic as a heat transfer medium

    SciTech Connect (OSTI)

    Assoufid, L.; Khounsary, A. [Experimental Facilities Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)] [Experimental Facilities Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    1996-09-01T23:59:59.000Z

    The results of an experimental study of the contact heat conductance across a single diamond crystal interface with OFHC copper (Cu) are reported. Gallium-indium (GaIn) eutectic was used as an interstitial material. Contact conductance data are important in the design and the prediction of the performance of x-ray optics under high-heat-load conditions. Two sets of experiments were carried out. In one, the copper surface in contact with diamond was polished and then electroless plated with 1 {mu}m of nickel, while in the other, the copper contact surface was left as machined. The measured average interface heat conductances are 44.7{plus_minus}8 W/cm{sup 2}-K for nonplated copper and 23.0{plus_minus}8 W/cm{sup 2}-K for nickel-plated copper. For reference, the thermal contact conductances at a copper-copper interface (without diamond) were also measured, and the results are reported. A typical diamond monochromator, 0.2 mm thick, will absorb about 44 W under a standard undulator beam at the Advanced Photon Source. The measured conductance for nickel-plated copper suggests that the temperature drop across the interface of diamond and nickel-plated copper, with a 20 mm {sup 2}contact area, will be about 10{degree}C. Therefore temperature rises are rather modest, and the accuracy of the measured contact conductances presented here are sufficient for design purposes. {copyright} {ital 1996 American Institute of Physics.}

  13. Thermal Energy Storage/Heat Recovery and Energy Conservation in Food Processing

    E-Print Network [OSTI]

    Combes, R. S.; Boykin, W. B.

    1980-01-01T23:59:59.000Z

    discharges can be made more economically attrac tank holding several thousand gallons of water tive by incorporating thermal energy storage in a maintained at 128-130?F. This scald tank is con heat recovery system. Thermal energy storage can stantly... the ultimate energy end use. of wasting this hot water to the plant drain, a heat A project conducted by the Georgia Tech exchanger was installed at the Gold Kist plant to Engineering Experiment Station to demonstrate preheat scald tank makeup water...

  14. Passive Solar Building Design and Solar Thermal Space Heating Webinar

    Broader source: Energy.gov [DOE]

    Webinar of National Renewable Energy Laboratory (NREL) Senior Engineer Andy Walker's presentation about passive solar building design and solar thermal space heating technologies and applications.

  15. Conduction Effect of Thermal Radiation in a Metal Shield Pipe in a Cryostat for a Cryogenic Interferometric Gravitational Wave Detector

    E-Print Network [OSTI]

    Takayuki Tomaru; Masao Tokunari; Kazuaki Kuroda; Takashi Uchiyama; Akira Okutomi; Masatake Ohashi; Hiroyuki Kirihara; Nobuhiro Kimura; Yoshio Saito; Nobuaki Sato; Takakazu Shintomi; Toshikazu Suzuki; Tomiyoshi Haruyama; Shinji Miyoki; Kazuhiro Yamamoto; Akira Yamamoto

    2007-11-06T23:59:59.000Z

    A large heat load caused by thermal radiation through a metal shield pipe was observed in a cooling test of a cryostat for a prototype of a cryogenic interferometric gravitational wave detector. The heat load was approximately 1000 times larger than the value calculated by the Stefan-Boltzmann law. We studied this phenomenon by simulation and experiment and found that it was caused by the conduction of thermal radiation in a metal shield pipe.

  16. Remarkable Reduction of Thermal Conductivity in Silicon Nanotubes

    E-Print Network [OSTI]

    Li, Baowen

    localization, thermoelectric material T hermoelectric (TE) materials can provide electricity when subjected materials can be characterized by the dimen- sionless thermoelectric figure of merit ZT ) S2 T/, where S to be responsible for the reduction of thermal conductivity. Our study suggests SiNT is a promising thermoelectric

  17. Mode dependent lattice thermal conductivity of single layer graphene

    SciTech Connect (OSTI)

    Wei, Zhiyong; Yang, Juekuan; Bi, Kedong; Chen, Yunfei, E-mail: yunfeichen@seu.edu.cn [Jiangsu Key Laboratory for Design and Manufacture of Micro/Nano Biomedical Instruments and School of Mechanical Engineering, Southeast University, Nanjing 210096 (China)

    2014-10-21T23:59:59.000Z

    Molecular dynamics simulation is performed to extract the phonon dispersion and phonon lifetime of single layer graphene. The mode dependent thermal conductivity is calculated from the phonon kinetic theory. The predicted thermal conductivity at room temperature exhibits important quantum effects due to the high Debye temperature of graphene. But the quantum effects are reduced significantly when the simulated temperature is as high as 1000?K. Our calculations show that out-of-plane modes contribute about 41.1% to the total thermal conductivity at room temperature. The relative contribution of out-of-plane modes has a little decrease with the increase of temperature. Contact with substrate can reduce both the total thermal conductivity of graphene and the relative contribution of out-of-plane modes, in agreement with previous experiments and theories. Increasing the coupling strength between graphene and substrate can further reduce the relative contribution of out-of-plane modes. The present investigations also show that the relative contribution of different mode phonons is not sensitive to the grain size of graphene. The obtained phonon relaxation time provides useful insight for understanding the phonon mean free path and the size effects in graphene.

  18. Measurement of the thermal conductance of the graphene/SiO2 interface Kin Fai Mak, Chun Hung Lui, and Tony F. Heinz

    E-Print Network [OSTI]

    Heinz, Tony F.

    , 043112 (2012) Opposite ReD-dependencies of nanofluid (Al2O3) thermal conductivities between heating and cooling modes Appl. Phys. Lett. 101, 083111 (2012) Thermal transport in graphene supported on copper J of thermal transport in this material system2­4 is currently less advanced. The thermal transport properties

  19. Thermal Crosslinking of Organic Semiconducting Polythiophene Improves Transverse Hole Conductivity

    SciTech Connect (OSTI)

    Gearba, I.R.; Nam, C.-Y.; Pindak, R.; Black, C.T.

    2009-10-26T23:59:59.000Z

    Thermal crosslinking using a suitable radical initiator simultaneously improves electrical conductivity in the semiconducting polymer poly(3-hexylthiophene) and makes the material insoluble. Crosslinked polythiophene shows as much as a fivefold increase in hole conductivity across the film thickness without any shift in spectral light absorption. Grazing incidence x-ray diffraction reveals more in-plane polymer lamellae stacking with only a small decrease in film crystallinity. Improved transverse conductivity increases the performance of model planar solar cells by threefold, from 0.07% to 0.2%. The ability to render polythiophene insoluble without disrupting film structural order enables fabrication pathways to more complex device architectures.

  20. Esimation of field-scale thermal conductivities of unsaturatedrocks from in-situ temperature data

    SciTech Connect (OSTI)

    Mukhopadhyay, Sumit; Tsang, Yvonne W.; Birkholzer, Jens T.

    2006-06-26T23:59:59.000Z

    A general approach is presented here which allows estimationof field-scale thermal properties of unsaturated rock using temperaturedata collected from in situ heater tests. The approach developed here isused to determine the thermal conductivities of the unsaturated host rockof the Drift Scale Test (DST) at Yucca Mountain, Nevada. The DST wasdesigned to obtain thermal, hydrological, mechanical, and chemical (THMC)data in the unsaturated fractured rock of Yucca Mountain. Sophisticatednumerical models have been developed to analyze these THMC data. However,though the objective of those models was to analyze "field-scale" (of theorder of tens-of-meters) THMC data, thermal conductivities measured from"laboratory-scale" core samples have been used as input parameters.While, in the absence of a better alternative, using laboratory-scalethermal conductivity values in field-scale models can be justified, suchapplications introduce uncertainties in the outcome of the models. Thetemperature data collected from the DST provides a unique opportunity toresolve some of these uncertainties. These temperature data can be usedto estimate the thermal conductivity of the DST host rock and, given thelarge volume of rock affected by heating at the DST, such an estimatewill be a more reliable effective thermal conductivity value for fieldscale application. In this paper, thus, temperature data from the DST areused to develop an estimate of the field-scale thermal conductivityvalues of the unsaturated host rock of the DST. An analytical solution isdeveloped for the temperature rise in the host rock of the DST; and usinga nonlinear fitting routine, a best-fit estimate of field-scale thermalconductivity for the DST host rock is obtained. Temperature data from theDST show evidence of two distinct thermal regimes: a zone below boiling(wet) and a zone above boiling (dry). Estimates of thermal conductivityfor both the wet and dry zones are obtained in this paper. Sensitivity ofthese estimates to the input heating power of the DST is alsoinvestigated in this paper. These estimated thermal conductivity valuesare compared with core measurements and those estimated fromgeostatistical simulations. Note that the approach presented here isapplicable to other host rock and heater test settings, provided suitablemodifications are made in the analytical solution to account fordifferences in test geometry.

  1. Large Deviations in Stochastic Heat-Conduction Processes Provide a Gradient-Flow Structure for Heat Conduction

    E-Print Network [OSTI]

    Mark A. Peletier; Frank Redig; Kiamars Vafayi

    2014-03-19T23:59:59.000Z

    We consider three one-dimensional continuous-time Markov processes on a lattice, each of which models the conduction of heat: the family of Brownian Energy Processes with parameter $m$, a Generalized Brownian Energy Process, and the Kipnis-Marchioro-Presutti process. The hydrodynamic limit of each of these three processes is a parabolic equation, the linear heat equation in the case of the BEP$(m)$ and the KMP, and a nonlinear heat equation for the GBEP($a$). We prove the hydrodynamic limit rigorously for the BEP$(m)$, and give a formal derivation for the GBEP($a$). We then formally derive the pathwise large-deviation rate functional for the empirical measure of the three processes. These rate functionals imply gradient-flow structures for the limiting linear and nonlinear heat equations. We contrast these gradient-flow structures with those for processes describing the diffusion of mass, most importantly the class of Wasserstein gradient-flow systems. The linear and nonlinear heat-equation gradient-flow structures are each driven by entropy terms of the form $-\\log \\rho$; they involve dissipation or mobility terms of order $\\rho^2$ for the linear heat equation, and a nonlinear function of $\\rho$ for the nonlinear heat equation.

  2. Determination of Thermal Diffusivities, Thermal Conductivities, and Sound Speeds of Room-Temperature Ionic Liquids by the Transient Grating Technique

    E-Print Network [OSTI]

    Reid, Scott A.

    Determination of Thermal Diffusivities, Thermal Conductivities, and Sound Speeds of Room. The experiments give thermal diffusivities from which thermal conductivities can be determined, sound speeds not only on the sound speed but also on the thermal diffusivity and acoustic damping of the RTILs

  3. Atomistic calculation of the thermal conductance of large scale bulk-nanowire junctions

    SciTech Connect (OSTI)

    Duchemin, Ivan; Donadio, Davide [Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz (Germany)

    2011-09-15T23:59:59.000Z

    We have developed a stable and efficient kernel method to compute thermal transport in open systems, based on the scattering-matrix approach. This method is applied to compute the thermal conductance of a junction between bulk silicon and silicon nanowires with diameter up to 10 nm. We have found that beyond a threshold diameter of 7 nm, transmission spectra and contact conductances scale with the cross section of the contact surface, whereas deviations from this general trend are observed in thinner wires. This result allows us to predict the thermal resistance of bulk-nanowire interfaces with larger cross sections than those tractable with atomistic simulations, and indicate the characteristic size beyond which atomistic systems can in principle be treated accurately by mean-field theories. Our calculations also elucidate how dimensionality reduction and shape affect interfacial heat transport.

  4. Ferrocyanide safety program: Heat load and thermal characteristics determination for selected tanks

    SciTech Connect (OSTI)

    McLaren, J.M.; Cash, R.J.

    1993-11-01T23:59:59.000Z

    An analysis was conducted to determine the heat loads, conductivities, and heat distributions of waste tanks 241-BY-105, -106, -108, -110, -111, and 241-C-109 at the Hanford Site. The heat distribution of tank 241-BY-111 was determined to be homogeneously distributed throughout the sludge contained in the tank. All of the other tanks, with the exception of 241-C-109, showed evidence of a heat-producing layer at the bottom of the tanks. No evidence of a heat-producing layer in a position above the bottom was found. The thermal conductivities were determined to be within the ranges found by previous laboratory and computer analysis. The heat loads of the tanks were found to be below 2.81 kW (9,600 Btu/hr).

  5. Measurements of the apparent thermal conductivity of multi-layer insulation between 20 K and 90 K

    SciTech Connect (OSTI)

    Hurd, Joseph A.; Van Sciver, Steven W. [National High Magnetic Field Laboratory Tallahassee, FL 32310 USA and FAMU-FSU College of Engineering, Department of M.E., Tallahassee, FL 32310 (United States)

    2014-01-29T23:59:59.000Z

    NASA has the need to efficiently store cryogenic propellants in space for long periods of time. One method to improve storage efficiency is to use multi-layer insulation (MLI), a technique that minimizes the boiling rate due to radiation heat transfer. Typically, the thermal performance of MLI is determined by measuring the rate of evaporation of liquid nitrogen from a calibrated cryostat. The main limitation with this method is that testing conditions are restricted by the boiling temperature of the LN{sub 2}, which may not match the requirements of the application. The Multi-Layer Insulation Thermal Conductivity Experiment (MIKE) at the National High Magnetic Field Laboratory is capable of measuring the effective thermal conductivity of MLI at variable boundary temperatures. MIKE uses cryo-refrigerators to control boundary temperatures in the calorimeter and a calibrated thermal link to measure the heat load. To make the measurements requested by NASA, MIKE needed to be recalibrated for the 20 K to 90 K range. Also, due to the expectation of a lower heat transfer rate, the heat load support rod material was changed to one with a lower thermal conductivity to ensure the temperature difference seen on the cold rod could be measurable at the estimated heat load. Presented are the alterations to MIKE including calibration data and heat load measurements on new load-bearing MLI supplied by NASA.

  6. Lattice thermal conductivity of filled skutterudites: An anharmonicity perspective

    SciTech Connect (OSTI)

    Geng, Huiyuan, E-mail: genghuiyuan@hit.edu.cn; Meng, Xianfu; Zhang, Hao; Zhang, Jian [State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001 (China)

    2014-10-28T23:59:59.000Z

    We report a phenomenological model to calculate the high-temperature lattice thermal conductivity of filled skutterudite antimonides. The model needs no phonon resonant scattering terms. Instead, we assume that umklapp processes dominate the high-temperature phonon scattering. In order to represent the anharmonicity introduced by the filling atom, we introduce a Gaussian term into the relaxation time of the umklapp process. The developed model agrees remarkably well with the experimental results of RE{sub f}Co{sub 4}Sb{sub 12} and RE{sub f}Fe{sub 4}Sb{sub 12} (RE?=?Yb, Ba, and Ca) alloys. To further test the validity of our model, we calculate the lattice thermal conductivity of nanostructured or multi-filled skutterudites. The calculation results are also in good agreement with experiment, increasing our confidence in the developed anharmonicity model.

  7. FDTD simulation of induction heating of conducting ceramic ware

    SciTech Connect (OSTI)

    White, M.J.; Iskander, M.F.; Bringhurst, S. [Univ. of Utah, Salt Lake City, UT (United States). Electrical Engineering Dept.

    1996-12-31T23:59:59.000Z

    Induction heating for the treatment of metals has been in commercial use since the mid 1960`s. Traditional advantages of induction heating over the convection or radiation processes include speed of heating, possible energy savings, and the ability to customize the coil design to optimize the heating process. In this paper the authors used the Finite-Difference Time-Domain (FDTD) technique to simulate and analyze the induction heating process for highly conducting ceramics. In order to analyze frequency effects, simulations were performed at 300 kHz, 2 MHz, and 25 MHz. It is found that at higher frequencies coils with a pitch of 2 in. or greater became capacitive and generate a large, axial, electric-field component. This new axial electric field, in addition to the normally encountered azimuthal field, causes an improvement in the uniformity of the power deposition in the ceramic sample. If the sample occupies a large portion of the coil, uniformity may also be improved by using a variable-pitch coil, or by extending the length of the coil a few turns beyond the length of the sample. In a production-line arrangement, where multiple samples are placed inside the coil, it is shown that maximum uniformity is achieved when the samples are placed coaxially.

  8. Experimental investigation on the photovoltaic-thermal solar heat pump air-conditioning system on water-heating mode

    SciTech Connect (OSTI)

    Fang, Guiyin; Hu, Hainan; Liu, Xu [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2010-09-15T23:59:59.000Z

    An experimental study on operation performance of photovoltaic-thermal solar heat pump air-conditioning system was conducted in this paper. The experimental system of photovoltaic-thermal solar heat pump air-conditioning system was set up. The performance parameters such as the evaporation pressure, the condensation pressure and the coefficient of performance (COP) of heat pump air-conditioning system, the water temperature and receiving heat capacity in water heater, the photovoltaic (PV) module temperature and the photovoltaic efficiency were investigated. The experimental results show that the mean photovoltaic efficiency of photovoltaic-thermal (PV/T) solar heat pump air-conditioning system reaches 10.4%, and can improve 23.8% in comparison with that of the conventional photovoltaic module, the mean COP of heat pump air-conditioning system may attain 2.88 and the water temperature in water heater can increase to 42 C. These results indicate that the photovoltaic-thermal solar heat pump air-conditioning system has better performances and can stably work. (author)

  9. Impulsive Spot Heating and Thermal Explosion of Interstellar Grains Revisited

    E-Print Network [OSTI]

    Ivlev, A V; Vasyunin, A; Caselli, P

    2015-01-01T23:59:59.000Z

    The problem of impulsive heating of dust grains in cold, dense interstellar clouds is revisited theoretically, with the aim to better understand leading mechanisms of the explosive desorption of icy mantles. It is rigorously shown that if the heating of a reactive medium occurs within a sufficiently localized spot (e.g., heating of mantles by cosmic rays), then the subsequent thermal evolution is characterized by a single dimensionless number $\\lambda$. This number identifies a bifurcation between two distinct regimes: When $\\lambda$ exceeds a critical value (threshold), the heat equation exhibits the explosive solution, i.e., the thermal (chemical) explosion is triggered. Otherwise, thermal diffusion causes the deposited heat to spread over the entire grain -- this regime is commonly known as the whole-grain heating. The theory allows us to find a critical combination of the physical parameters that govern the explosion of icy mantles due to impulsive spot heating. In particular, the calculations suggest tha...

  10. Investigation of new heat exchanger design performance for solar thermal chemical heat pump.

    E-Print Network [OSTI]

    Cordova, Cordova

    2013-01-01T23:59:59.000Z

    ?? The emergence of Thermally Driven Cooling system has received more attention recently due to its ability to utilize low grade heat from engine, incinerator… (more)

  11. High-Throughput Computational Screening of thermal conductivity, Debye temperature and Gruneisen parameter

    E-Print Network [OSTI]

    Curtarolo, Stefano

    thermal properties such as the Debye temperature and the thermal conductivity of materials. We demonstrate studied for the past few decades6 . Low thermal conductivity mate- rials constitute the basis of a new and predict the thermal conductivity of differ- ent materials8,9,11­16 . Such evaluation of the higher

  12. Enhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid

    E-Print Network [OSTI]

    by their very low thermal conductivity. These fluids have almost two orders of magnitude lower thermal, a significant amount of data has been gathered on the thermal conductivity of nanofluids. Typical materials usedEnhanced thermal conductivity and viscosity of copper nanoparticles in ethylene glycol nanofluid J

  13. E-Print Network 3.0 - anomalous heat conduction Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    parallel studies of the upper ocean heat budget have been conducted... of the anomalous heat ... Source: Kelly, Kathryn A. - Air-Sea Interaction and Remote Sensing Department,...

  14. E-Print Network 3.0 - apparent thermal conductivity Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    293 K. To obtain data... results 4,5. Comparing to the apparent thermal conductivity of aerogel when the boundary temperatures... THERMAL ... Source: Chang, Ho-Myung - Department...

  15. E-Print Network 3.0 - angle-resolved thermal conductivity Sample...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    single-walled carbon nanotube films Kei... , the expectation on single-walled carbon nanotubes (SWNTs) to possess high thermal conductivity has attracted... of the thermal...

  16. Pump-probe measurements of the thermal conductivity tensor for materials lacking in-plane symmetry

    E-Print Network [OSTI]

    Cahill, David G.

    1 Pump-probe measurements of the thermal conductivity tensor for materials lacking in conductivity corresponding to the scanning direction. Also, we demonstrate Nb- V as a low thermal conductivity thermal conductivity tensor and the illuminating spots have arbitrary intensity profiles

  17. Submitted to Phys. Rev. B, June 2013 Ultralow thermal conductivity of fullerene derivatives

    E-Print Network [OSTI]

    Cahill, David G.

    conductivity in WSe2. The objective our study is to verify the exceptionally low thermal conductivities of these materials might affect their thermal conductivities. In addition to PCBM, we also investigate [6,6]-phenyl on the appearance of ultralow thermal conductivity in this class of materials. We use time-domain thermoreflectance

  18. Uncertainty Analysis on the Design of Thermal Conductivity Measurement by a Guarded Cut-Bar Technique

    SciTech Connect (OSTI)

    Jeff Phillips; Changhu Xing; Colby Jensen; Heng Ban1

    2011-07-01T23:59:59.000Z

    A technique adapted from the guarded-comparative-longitudinal heat flow method was selected for the measurement of the thermal conductivity of a nuclear fuel compact over a temperature range characteristic of its usage. This technique fulfills the requirement for non-destructive measurement of the composite compact. Although numerous measurement systems have been created based on the guarded comparative method, comprehensive systematic (bias) and measurement (precision) uncertainty associated with this technique have not been fully analyzed. In addition to the geometric effect in the bias error, which has been analyzed previously, this paper studies the working condition which is another potential error source. Using finite element analysis, this study showed the effect of these two types of error sources in the thermal conductivity measurement process and the limitations in the design selection of various parameters by considering their effect on the precision error. The results and conclusions provide valuable reference for designing and operating an experimental measurement system using this technique.

  19. Effective thermal conductivity of packed beds of spheres

    E-Print Network [OSTI]

    Duncan, Allen Buchanan

    1987-01-01T23:59:59.000Z

    of N are known only for certain types of regular packing, however, an empirical relation for m ) 0. 3 is given as N = 11. 6(l ? m) (22) When a load is applied to a bed of spheres, the contact area between spheres is determined using the Hertz... the authors compared their analytical solutions to has consistently dealt with beds of materials which have a very low thermal conductivity compared to that of the brass and aluminum spheres. These materials have been solid and hollow glass spheres, ceramic...

  20. Minnesota Power- Solar-Thermal Water Heating Rebate Program

    Broader source: Energy.gov [DOE]

    Minnesota Power offers a 25% rebate for qualifying solar thermal water heating systems. The maximum award for single-family customers is $2,000 per customer; $4,000 for 2-3 family unit buildings; ...

  1. Thermally Activated Desiccant Technology for Heat Recovery and Comfort

    SciTech Connect (OSTI)

    Jalalzadeh, A. A.

    2005-11-01T23:59:59.000Z

    Desiccant cooling is an important part of the diverse portfolio of Thermally Activated Technologies (TAT) designed for conversion of heat for the purpose of indoor air quality control. Thermally activated desiccant cooling incorporates a desiccant material that undergoes a cyclic process involving direct dehumidification of moist air and thermal regeneration. Desiccants fall into two categories: liquid and solid desiccants. Regardless of the type, solid or liquid, the governing principles of desiccant dehumidification systems are the same. In the dehumidification process, the vapor pressure of the moist air is higher than that of the desiccant, leading to transfer of moisture from the air to the desiccant material. By heating the desiccant, the vapor pressure differential is reversed in the regeneration process that drives the moisture from the desiccant. Figure 1 illustrates a rotary solid-desiccant dehumidifier. A burner or a thermally compatible source of waste heat can provide the required heat for regeneration.

  2. Gulf Power- Solar Thermal Water Heating Program

    Broader source: Energy.gov [DOE]

    '''''This program reopened on October 3, 2011 for 2012 applications. Funding is limited and must be reserved through online application before the installation of qualifying solar water heating...

  3. Thermal insulation by heat resistant polymers.

    E-Print Network [OSTI]

    Ahmed, Ashraf Fathy

    2009-01-01T23:59:59.000Z

    ??Internal insulation in a solid rocket motor is a layer of heat-barrier material placed between the internal surface of the case and the propellant. The… (more)

  4. Method and apparatus for producing a carbon based foam article having a desired thermal-conductivity gradient

    DOE Patents [OSTI]

    Klett, James W. (Knoxville, TN) [Knoxville, TN; Cameron, Christopher Stan (Sanford, NC) [Sanford, NC

    2010-03-02T23:59:59.000Z

    A carbon based foam article is made by heating the surface of a carbon foam block to a temperature above its graphitizing temperature, which is the temperature sufficient to graphitize the carbon foam. In one embodiment, the surface is heated with infrared pulses until heat is transferred from the surface into the core of the foam article such that the graphitizing temperature penetrates into the core to a desired depth below the surface. The graphitizing temperature is maintained for a time sufficient to substantially entirely graphitize the portion of the foam article from the surface to the desired depth below the surface. Thus, the foam article is an integral monolithic material that has a desired conductivity gradient with a relatively high thermal conductivity in the portion of the core that was graphitized and a relatively low thermal conductivity in the remaining portion of the foam article.

  5. Thermal conductivity of the electrode gap of a thermionic converter, filled with inert gases, at low pressures

    SciTech Connect (OSTI)

    Modin, V.A.; Nikolaev, Y.V.

    1985-11-01T23:59:59.000Z

    Experimental data is presented on the thermal conductivity of the electrode gap of a thermionic converter filled with He, Ar, and Xe in the pressure range 40--550 Pa. The need to account for the coefficients of thermal accommodation of the emitter-inert-gas-collector system in this range is shown. The accommodation coefficients for different temperature regimes are measured and expressions are obtained to calculate the heat flux transported by the inert gases in the electrode gap.

  6. Numerical solution of 2-D nonlinear inverse heat conduction problems using finite-element techniques

    SciTech Connect (OSTI)

    Khachfe, R.A.; Jarny, Y.

    2000-02-01T23:59:59.000Z

    A general method is presented for solving different classes of nonlinear inverse heat conduction problems (IHCP) for two-dimensional, arbitrarily shaped bodies. It is based on the systematic use of a finite-element library. It is shown that, following this approach, the conjugate gradient method can be easily implemented. The method offers a very wide field of practical applications in inverse thermal analysis, while reducing very significantly the amount of work which remains specific for each particular IHPC. Two numerical experiments illustrate the influence of data errors and the iterative regularization principle.

  7. Experimental Investigation of Size Effects on the Thermal Conductivity of Silicon-Germanium Alloy Thin Films

    E-Print Network [OSTI]

    Cheaito, Ramez

    We experimentally investigate the role of size effects and boundary scattering on the thermal conductivity of silicon-germanium alloys. The thermal conductivities of a series of epitaxially grown Si[subscript 1-x] Ge[subscript ...

  8. Thermal Properties of Uranium-Molybdenum Alloys: Phase Decomposition Effects of Heat Treatments

    E-Print Network [OSTI]

    Creasy, John Thomas

    2012-02-14T23:59:59.000Z

    to generate computational estimates of the alloys specific heat and thermal conductivity. Section 2 describes the technical background in which this thesis is based, including uranium metal alloy theory and properties. Section 3 describes the experimental... the phases and distorted phases that occur during phase decomposition. The authors conducted numerous experiments involving uranium, plutonium, and neptunium, as well as alloys with other metals. In the a0 = 3.4808 ! 0.00314 xMo !" Mox ? 10 case...

  9. Design of a steady state thermal conductivity measurement device for CNT RET polymer composites

    E-Print Network [OSTI]

    Louie, Brian Ming

    2011-01-01T23:59:59.000Z

    NY: Taylor & Francis. [10] Tritt, T. M. (2004). MeasurementBulk Materials. In T. M. Tritt, Thermal Conductivity Theory,

  10. High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems

    SciTech Connect (OSTI)

    Tarau, Calin; Walker, Kara L.; Anderson, William G. [Advanced Cooling Technologies, Inc. 1046 New Holland Ave. Lancaster, PA 17601 (United States)

    2009-03-16T23:59:59.000Z

    In a Stirling radioisotope system, heat must continually be removed from the GPHS modules, to maintain the GPHS modules and surrounding insulation at acceptable temperatures. Normally, the Stirling converter provides this cooling. If the Stirling engine stops in the current system, the insulation is designed to spoil, preventing damage to the GPHS, but also ending the mission. An alkali-metal Variable Conductance Heat Pipe (VCHP) is under development to allow multiple stops and restarts of the Stirling engine. The status of the ongoing effort in developing this technology is presented in this paper. An earlier, preliminary design had a radiator outside the Advanced Stirling Radioisotope Generator (ASRG) casing, used NaK as the working fluid, and had the reservoir located on the cold side adapter flange. The revised design has an internal radiator inside the casing, with the reservoir embedded inside the insulation. A large set of advantages are offered by this new design. In addition to reducing the overall size and mass of the VCHP, simplicity, compactness and easiness in assembling the VCHP with the ASRG are significantly enhanced. Also, the permanently elevated temperatures of the entire VCHP allows the change of the working fluid from a binary compound (NaK) to single compound (Na). The latter, by its properties, allows higher performance and further mass reduction of the system. Preliminary design and analysis shows an acceptable peak temperature of the ASRG case of 140 deg. C while the heat losses caused by the addition of the VCHP are 1.8 W.

  11. Report on workshop on thermal property measurements

    SciTech Connect (OSTI)

    Robertson, E.C.

    1987-01-01T23:59:59.000Z

    Results of thermogravimetric analysis of basalt is discussed. Heat capacity, thermal conductivity and thermal expansion are specifically addressed. (CBS)

  12. Anomalous thermal conduction characteristics of phase change composites with single walled carbon nanotube inclusions

    E-Print Network [OSTI]

    Maruyama, Shigeo

    of the phase change materials, because low thermal conductivity hinders the rate of energy storage and release of the new way of improving the thermal conductivity of phase change materials by seeding nano materials way to manipulate the thermal conductivity of nano composites using one dimensional nano material

  13. Origin of Low Thermal Conductivity in Nuclear Fuels Quan Yin and Sergey Y. Savrasov

    E-Print Network [OSTI]

    Savrasov, Sergej Y.

    , the thermal conductivity of UO2 is very low, and the search for alternative materials continuesOrigin of Low Thermal Conductivity in Nuclear Fuels Quan Yin and Sergey Y. Savrasov Department in a very low thermal conductivity of modern nuclear fuels. Consider semiconducting UO2 which is a main

  14. Numerical heat conduction in hydrodynamical models of colliding hypersonic flows

    E-Print Network [OSTI]

    Parkin, E R

    2010-01-01T23:59:59.000Z

    Hydrodynamical models of colliding hypersonic flows are presented which explore the dependence of the resulting dynamics and the characteristics of the derived X-ray emission on numerical conduction and viscosity. For the purpose of our investigation we present models of colliding flow with plane-parallel and cylindrical divergence. Numerical conduction causes erroneous heating of gas across the contact discontinuity which has implications for the rate at which the gas cools. We find that the dynamics of the shocked gas and the resulting X-ray emission are strongly dependent on the contrast in the density and temperature either side of the contact discontinuity, these effects being strongest where the postshock gas of one flow behaves quasi-adiabatically while the postshock gas of the other flow is strongly radiative. Introducing additional numerical viscosity into the simulations has the effect of damping the growth of instabilities, which in some cases act to increase the volume of shocked gas and can re-he...

  15. Numerical investigation of CO{sub 2} emission and thermal stability of a convective and radiative stockpile of reactive material in a cylindrical pipe of variable thermal conductivity

    SciTech Connect (OSTI)

    Lebelo, Ramoshweu Solomon, E-mail: sollyl@vut.ac.za [Department of Mathematics, Vaal University of Technology, Private Bag X021, Vanderbijlpark, 1911 (South Africa)

    2014-10-24T23:59:59.000Z

    In this paper the CO{sub 2} emission and thermal stability in a long cylindrical pipe of combustible reactive material with variable thermal conductivity are investigated. It is assumed that the cylindrical pipe loses heat by both convection and radiation at the surface. The nonlinear differential equations governing the problem are tackled numerically using Runge-Kutta-Fehlberg method coupled with shooting technique method. The effects of various thermophysical parameters on the temperature and carbon dioxide fields, together with critical conditions for thermal ignition are illustrated and discussed quantitatively.

  16. Aquifer thermal energy (heat and chill) storage

    SciTech Connect (OSTI)

    Jenne, E.A. (ed.)

    1992-11-01T23:59:59.000Z

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  17. DIRECT MEASUREMENT OF HEAT FLUX FROM COOLING LAKE THERMAL IMAGERY

    SciTech Connect (OSTI)

    Garrett, A; Eliel Villa-Aleman, E; Robert Kurzeja, R; Malcolm Pendergast, M; Timothy Brown, T; Saleem Salaymeh, S

    2007-12-19T23:59:59.000Z

    Laboratory experiments show a linear relationship between the total heat flux from a water surface to air and the standard deviation of the surface temperature field, {sigma}, derived from thermal images of the water surface over a range of heat fluxes from 400 to 1800 Wm{sup -2}. Thermal imagery and surface data were collected at two power plant cooling lakes to determine if the laboratory relationship between heat flux and {sigma} exists in large heated bodies of water. The heat fluxes computed from the cooling lake data range from 200 to 1400 Wm{sup -2}. The linear relationship between {sigma} and Q is evident in the cooling lake data, but it is necessary to apply band pass filtering to the thermal imagery to remove camera artifacts and non-convective thermal gradients. The correlation between {sigma} and Q is improved if a correction to the measured {sigma} is made that accounts for wind speed effects on the thermal convection. Based on more than a thousand cooling lake images, the correlation coefficients between {sigma} and Q ranged from about 0.8 to 0.9.

  18. Effects of temperature and disorder on thermal boundary conductance at solidsolid interfaces: Nonequilibrium

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    with the constituent materials. The inter- face thermal resistance, often referred to as thermal boundary resistance between two different materials when a heat flux is applied. The inverse of thermal boundary resistance mismatched interfaces. Ã? 2007 Elsevier Ltd. All rights reserved. Keywords: Thermal boundary resistance

  19. Spatially localized measurement of thermal conductivity using a hybrid photothermal technique

    SciTech Connect (OSTI)

    David H Hurley; Marat Khafizov; Zilong Hua; Rory Kennedy; Heng Ban

    2012-05-01T23:59:59.000Z

    A photothermal technique capable of measuring thermal conductivity with micrometer lateral resolution is presented. This technique involves measuring separately the thermal diffusivity, D, and thermal effusivity, e, to extract the thermal conductivity, k=(e2/D)1/2. To generalize this approach, sensitivity analysis was conducted for materials having a range of thermal conductivities. Experimental validation was sought using two substrate materials, SiO2 and CaF2, both coated with thin titanium films. The measured conductivities compare favorably with literature values.

  20. Thermal interface conductance across a graphene/hexagonal boron nitride heterojunction

    SciTech Connect (OSTI)

    Chen, Chun-Chung; Li, Zhen; Cronin, Stephen B. [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Shi, Li [Department of Mechanical Engineering and Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712 (United States)

    2014-02-24T23:59:59.000Z

    We measure thermal transport across a graphene/hexagonal boron nitride (h-BN) interface by electrically heating the graphene and measuring the temperature difference between the graphene and BN using Raman spectroscopy. Because the temperature of the graphene and BN are measured optically, this approach enables nanometer resolution in the cross-plane direction. A temperature drop of 60?K can be achieved across this junction at high electrical powers (14 mW). Based on the temperature difference and the applied power data, we determine the thermal interface conductance of this junction to be 7.4?×?10{sup 6}?Wm{sup ?2}K{sup ?1}, which is below the 10{sup 7}–10{sup 8}?Wm{sup ?2}K{sup ?1} values previously reported for graphene/SiO{sub 2} interface.

  1. Ballistic phonon thermal conductance in graphene nano-ribbon: First-principles calculations

    SciTech Connect (OSTI)

    Nakamura, Jun; Tomita, Hiroki [Department of Engineering Sciences, The University of Electro-Communications (UEC-Tokyo), 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585 (Japan)

    2013-12-04T23:59:59.000Z

    Ballistic phonon thermal conductances for graphene nanoribbons are investigated using first-principles calculations with the density functional perturbation theory and the Landauer theory. The phonon thermal conductance per unit width for GNR is larger than that for graphene and increases with decreasing ribbon width. The normalized thermal conductances with regard to a thermal quantum for GNRs are higher than those for the single-walled carbon nanotube that have circumferential lengths corresponding to the width of GNR.

  2. MODEL FOR DETERMINING THE EFFECTIVE THERMAL CONDUCTIVITY OF PARTICLE BEDS WITH HIGH SOLID-TO-GAS THERMAL

    E-Print Network [OSTI]

    Abdou, Mohamed

    -TO-GAS THERMAL CONDUCTIVITY RATIO A.R. Raffray, Z. Gorbis, A. Badawi, M.S. Tillack, A.Y. Ying, and M. A. Abdou

  3. Damage of MEMS thermal actuators heated by laser irradiation.

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen; Klody, Kelly Anne; Sackos, John T.; Phinney, Leslie Mary

    2004-11-01T23:59:59.000Z

    Optical actuation of microelectromechanical systems (MEMS) is advantageous for applications for which electrical isolation is desired. Thirty-two polycrystalline silicon opto-thermal actuators, optically-powered MEMS thermal actuators, were designed, fabricated, and tested. The design of the opto-thermal actuators consists of a target for laser illumination suspended between angled legs that expand when heated, providing the displacement and force output. While the amount of displacement observed for the opto-thermal actuators was fairly uniform for the actuators, the amount of damage resulting from the laser heating ranged from essentially no damage to significant amounts of damage on the target. The likelihood of damage depended on the target design with two of the four target designs being more susceptible to damage. Failure analysis of damaged targets revealed the extent and depth of the damage.

  4. Damage of MEMS thermal actuators heated by laser irradiation.

    SciTech Connect (OSTI)

    Walraven, Jeremy Allen; Klody, Kelly Anne; Sackos, John T.; Phinney, Leslie Mary

    2005-01-01T23:59:59.000Z

    Optical actuation of microelectromechanical systems (MEMS) is advantageous for applications for which electrical isolation is desired. Thirty-two polycrystalline silicon opto-thermal actuators, optically-powered MEMS thermal actuators, were designed, fabricated, and tested. The design of the opto-thermal actuators consists of a target for laser illumination suspended between angled legs that expand when heated, providing the displacement and force output. While the amount of displacement observed for the opto-thermal actuators was fairly uniform for the actuators, the amount of damage resulting from the laser heating ranged from essentially no damage to significant amounts of damage on the target. The likelihood of damage depended on the target design with two of the four target designs being more susceptible to damage. Failure analysis of damaged targets revealed the extent and depth of the damage.

  5. Molten Glass for Thermal Storage: Advanced Molten Glass for Heat Transfer and Thermal Energy Storage

    SciTech Connect (OSTI)

    None

    2012-01-01T23:59:59.000Z

    HEATS Project: Halotechnics is developing a high-temperature thermal energy storage system using a new thermal-storage and heat-transfer material: earth-abundant and low-melting-point molten glass. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Halotechnics new thermal storage material targets a price that is potentially cheaper than the molten salt used in most commercial solar thermal storage systems today. It is also extremely stable at temperatures up to 1200°C—hundreds of degrees hotter than the highest temperature molten salt can handle. Being able to function at high temperatures will significantly increase the efficiency of turning heat into electricity. Halotechnics is developing a scalable system to pump, heat, store, and discharge the molten glass. The company is leveraging technology used in the modern glass industry, which has decades of experience handling molten glass.

  6. Evaluating the ignition sensitivity of thermal battery heat pellets

    SciTech Connect (OSTI)

    Thomas, E.V.

    1993-09-01T23:59:59.000Z

    Thermal batteries are activated by the ignition of heat pellets. If the heat pellets are not sensitive enough to the ignition stimulus, the thermal battery will not activate, resulting in a dud. Thus, to assure reliable thermal batteries, it is important to demonstrate that the pellets have satisfactory ignition sensitivity by testing a number of specimens. There are a number of statistical methods for evaluating the sensitivity of a device to some stimulus. Generally, these methods are applicable to the situation in which a single test is destructive to the specimen being tested, independent of the outcome of the test. In the case of thermal battery heat pellets, however, tests that result in a nonresponse do not totally degrade the specimen. This peculiarity provides opportunities to efficiently evaluate the ignition sensitivity of heat pellets. In this paper, a simple strategy for evaluating heat pellet ignition sensitivity (including experimental design and data analysis) is described. The relatively good asymptotic and small-sample efficiencies of this strategy are demonstrated.

  7. Summary Weusedthreemethodstomeasureboundarylayer conductance to heat transfer (gbH) and water vapor transfer

    E-Print Network [OSTI]

    Martin, Timothy

    Summary Weusedthreemethodstomeasureboundarylayer conductance to heat transfer (gbH) and water vapor of transpiration). The boundary layer conductance to heat transfer is small enough that leaf temperature can become diffusion, the boundary layer around a leaf also provides resistance to the transfer of heat between a leaf

  8. Temperature measurements using multicolor pyrometry in thermal radiation heating environments

    SciTech Connect (OSTI)

    Fu, Tairan, E-mail: trfu@mail.tsinghua.edu.cn [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China) [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of CO2 Utilization and Reduction Technology, Beijing 100084 (China); Liu, Jiangfan; Duan, Minghao; Zong, Anzhou [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)] [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

    2014-04-15T23:59:59.000Z

    Temperature measurements are important for thermal-structural experiments in the thermal radiation heating environments such as used for thermal-structural stress analyses. This paper describes the use of multicolor pyrometry for the measurements of diffuse surfaces in thermal radiation environments that eliminates the effects of background radiation reflections and unknown emissivities based on a least-squares algorithm. The near-infrared multicolor pyrometer had a spectral range of 1100–2400 nm, spectrum resolution of 6 nm, maximum sampling frequency of 2 kHz, working distance of 0.6 m to infinity, temperature range of 700–1700 K. The pyrometer wavelength response, nonlinear intensity response, and spectral response were all calibrated. The temperature of a graphite sample irradiated by quartz lamps was then measured during heating and cooling using the least-squares algorithm based on the calibrated irradiation data. The experiments show that higher temperatures and longer wavelengths are more suitable for the thermal measurements in the quartz lamp radiation heating system. This analysis provides a valuable method for temperature measurements of diffuse surfaces in thermal radiation environments.

  9. ENS'07 Paris, France, 3-4 December 2007 MEASUREMENTS OF THERMAL CONDUCTIVITY OF ALUMINUM NANOPOWDERS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ENS'07 Paris, France, 3-4 December 2007 MEASUREMENTS OF THERMAL CONDUCTIVITY OF ALUMINUM spectroscopy (PAS) as a powerful technique to estimate thermal properties of aluminum nanosized powders. Aluminum nanopowders are considered as effective constituents of energetic materials. Thermal conductivity

  10. Computational modeling of thermal conductivity of single walled carbon nanotube polymer composites

    E-Print Network [OSTI]

    Maruyama, Shigeo

    to solid materials like metals. Keywords: SWNT, Random Walk, Thermal Conductivity, Composites 1 at the interface between the matrix material and the SWNT plays a very important role on the effective thermal conductivity. This thermal resistance is known as the Kapitza resistance [8]. According to the acoustic theory

  11. Thermal conductivity measurements of insulators for fusion blankets

    SciTech Connect (OSTI)

    Horn, F.L.; Fillo, J.A.; Powell, J.R.

    1981-01-01T23:59:59.000Z

    Alumina-silica mat (8 lb/ft/sup 3/) varied in thermal conductivity in air and Ar from 0.06 W/m- K at 300/sup 0/C to 0.22 W/m- K at 1000/sup 0/C, but in He it increased to 0.24 W/m- K at 300/sup 0/C and 0.54 W/m- K at 1000/sup 0/C, while in steam it was about midway between these values. The carbon and graphite felts behaved similarly, but the rigid and denser (24 lb/ft/sup 3/) zirconia fiberboard exhibited superior insulating properties: 0.07 W/m- K at 300/sup 0/C and 0.14 W/m- K at 1000/sup 0/C in air and Ar, and 0.13 W/m- K at 300/sup 0/C and 0.17 W/m- K at 1000/sup 0/C in steam, but rising to 0.15 W/m- K at 300/sup 0/C and 0.49 W/m- K at 1000/sup 0/C in He. The lighter zirconia felt (14 lb/ft/sup 3/) in steam at 1000/sup 0/C was thought to be best at 0.23 W/m- K and only 0.40 W/m- K in He at 1000/sup 0/C.

  12. Lattice thermal conductivity of self-assembled PbTe-Sb2Te3 composites with nanometer lamellae Teruyuki Ikeda1

    E-Print Network [OSTI]

    . In this work, the thermal conductivities and the electrical resistivities have been measured as functions for effective use of heat or electrical energy, it is essential to discover materials with a high thermoelectric to control the fraction transformed and inter-lamellar spacing. The electrical resistivity and the thermal

  13. Thermal conductance of buckled carbon nanotubes Fumio Nishimura1

    E-Print Network [OSTI]

    Maruyama, Shigeo

    with the strain energy generated in the buckle. Despite the highly stained deformation, the thermal resistance have motivated applications of carbon nanotubes as thermal interface materials [4-8] and additives in nanocomposites [9-12], in practice, one needs to consider various thermal resistances that manifest in the actual

  14. Thermal Conduction Path Analysis in 3-D ICs Boris Vaisband1

    E-Print Network [OSTI]

    Friedman, Eby G.

    in the temperature and thermal resistance of up to, respectively, 20% and 28%. As confirmed by simulation, those [9], [10]. Thermal flow in materials is described by the Fourier Law, q = -k · T . (1) Thermal-D stack. through a unit of area) q [ W m2 ], the thermal conductivity, a property of the material k

  15. Interfacial thermal conductance in spun-cast polymer films and polymer brushes

    E-Print Network [OSTI]

    Braun, Paul

    represents the length of a material of thermal conduc- tivity providing an equivalent thermal resistance inorganic materials and anharmonic polymers have potentially intriguing thermal transport behavior. The low. This requirement proves challenging for low thermal conductivity materials like amorphous polymers. The effective

  16. Fractal-like tree networks reducing the thermal conductivity Boming Yu1,

    E-Print Network [OSTI]

    Li, Baowen

    Fractal-like tree networks reducing the thermal conductivity Boming Yu1, * and Baowen Li1,2 1 conductivity of composites with embedded self-similar H-shaped fractal-like tree networks is studied that the thermal conductivity of the H-shaped fractal-like tree networks does not obey Murray's law. The present

  17. How Does Folding Modulate Thermal Conductivity of Graphene? Nuo Yang1,2

    E-Print Network [OSTI]

    Li, Baowen

    of thermal conductivity is due to scattering of low frequency phonons by the folds. Our results suggest dimensional materials. Keywords Folded graphene ribbon, thermal conductivity, phonon transport, scattering #12 conductivity of low-dimensional silicon and carbon materials11 and graphene ribbons12 were studied by EMD

  18. Ceramic materials with low thermal conductivity and low coefficients of thermal expansion

    DOE Patents [OSTI]

    Brown, Jesse (Christiansburg, VA); Hirschfeld, Deidre (Elliston, VA); Liu, Dean-Mo (Blacksburg, VA); Yang, Yaping (Blacksburg, VA); Li, Tingkai (Blacksburg, VA); Swanson, Robert E. (Blacksburg, VA); Van Aken, Steven (Blacksburg, VA); Kim, Jin-Min (Seoul, KR)

    1992-01-01T23:59:59.000Z

    Compositions having the general formula (Ca.sub.x Mg.sub.1-x)Zr.sub.4 (PO.sub.4).sub.6 where x is between 0.5 and 0.99 are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850.degree. C. for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200.degree. C. to 1350.degree. C. to form solid macrostructures with near-zero bulk coefficients of thermal expansion and low thermal conductivities. Porous macrostructures of the MgCZP powders of the present invention are also formed by combination with a polymeric powder and a binding agent, and sintering at high temperatures. The porosity of the resulting macrostructures can be adjusted by varying the particle size of the polymeric powder used.

  19. Ceramic materials with low thermal conductivity and low coefficients of thermal expansion

    DOE Patents [OSTI]

    Brown, J.; Hirschfeld, D.; Liu, D.M.; Yang, Y.; Li, T.; Swanson, R.E.; Van Aken, S.; Kim, J.M.

    1992-04-07T23:59:59.000Z

    Compositions, having the general formula (Ca[sub x]Mg[sub 1[minus]x])Zr[sub 4](PO[sub 4])[sub 6] where x is between 0.5 and 0.99, are produced by solid state and sol-gel processes. In a preferred embodiment, when x is between 0.5 and 0.8, the MgCZP materials have near-zero coefficients of thermal expansion. The MgCZPs of the present invention also show unusually low thermal conductivities, and are stable at high temperatures. Macrostructures formed from MgCZP are useful in a wide variety of high-temperature applications. In a preferred process, calcium, magnesium, and zirconium nitrate solutions have their pH adjusted to between 7 and 9 either before or after the addition of ammonium dihydrogen phosphate. After dehydration to a gel, and calcination at temperatures in excess of 850 C for approximately 16 hours, single phase crystalline MgCZP powders with particle sizes ranging from approximately 20 nm to 50 nm result. The MgCZP powders are then sintered at temperatures ranging from 1200 C to 1350 C to form solid macrostructures with near-zero bulk coefficients of thermal expansion and low thermal conductivities. Porous macrostructures of the MgCZP powders of the present invention are also formed by combination with a polymeric powder and a binding agent, and sintering at high temperatures. The porosity of the resulting macrostructures can be adjusted by varying the particle size of the polymeric powder used. 7 figs.

  20. Size dependent thermal conductivity of single-walled carbon nanotubes Ajing Cao and Jianmin Qu

    E-Print Network [OSTI]

    Chen, Wei

    . Phys. Lett. 100, 261908 (2012) Focus shift photothermal method for thermal diffusivity mapping J. Appl Institute of Physics. Related Articles Enhanced high thermal conductivity and low permittivity of polyimide

  1. Reversible temperature regulation of electrical and thermal conductivity using liquid–solid phase transitions

    E-Print Network [OSTI]

    Zheng, Ruiting

    Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce ...

  2. A Correction Scheme for Thermal Conductivity Measurement Using the Comparative Cut-bar Technique Based on a 3D Numerical Simulation

    SciTech Connect (OSTI)

    Douglas W. Marshall; Changhu Xing; Charles Folsom; Colby Jensen; Heng Ban

    2014-05-01T23:59:59.000Z

    As an important factor affecting the accuracy of the thermal conductivity measurement, systematic (bias) error in the guarded comparative axial heat flow (cut-bar) method was mostly neglected by previous researches. This bias is due primarily to the thermal conductivity mismatch between sample and meter bars (reference), which is common for a sample of unknown thermal conductivity. A correction scheme, based on a finite element simulation of the measurement system, was proposed to reduce the magnitude of the overall measurement uncertainty. This scheme was experimentally validated by applying corrections on four types of sample measurements in which the specimen thermal conductivity is much smaller, slightly smaller, equal and much larger than that of the meter bar. As an alternative to the optimum guarding technique proposed before, the correction scheme can be used to minimize uncertainty contribution from the measurement system with non-optimal guarding conditions. It is especially necessary for large thermal conductivity mismatches between sample and meter bars.

  3. Thermal conductivity, electrical resistivity, and permeability of saturated soils at various porosities

    E-Print Network [OSTI]

    Enderby, James Keith

    2012-06-07T23:59:59.000Z

    of Ottawa Sand . 4. Thermal Conductivity Data Analysis 5. Thermal Conductivity of Reference Materials 6. DC Resistivity Data with Plate Electrode System for Kaolinite at Porosity of 49% PAGE 48 52 54 66 71 AC Resistivity Data for Kaolinite... THERMAL CONDUCTIVITY, ELECTRICAL RESISTIVITY, AND PERMEABILITY OF SATURATED SOILS AT VARIOUS POROSITIES A Thesis by JAMES KEITH ENDERBY Submitted to the Graduate College of Texas ARM University in Partial fulfillment of the requirement...

  4. Methods for increasing the thermal conductivity of ultra-high molecular weight polyethylene (UHMWPE)

    E-Print Network [OSTI]

    Miler, Josef L

    2006-01-01T23:59:59.000Z

    A two-part study was conducted to determine methods for producing ultra-high molecular weight polyethylene with high thermal conductivity by way of polymer chain orientation. The first portion of this report surveys current ...

  5. Nonlinear vs. bolometric radiation response and phonon thermal conductance in graphene-superconductor junctions

    SciTech Connect (OSTI)

    Vora, Heli; Nielsen, Bent; Du, Xu [Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York (United States)

    2014-02-21T23:59:59.000Z

    Graphene is a promising candidate for building fast and ultra-sensitive bolometric detectors due to its weak electron-phonon coupling and low heat capacity. In order to realize a practical graphene-based bolometer, several important issues, including the nature of radiation response, coupling efficiency to the radiation and the thermal conductance need to be carefully studied. Addressing these issues, we present graphene-superconductor junctions as a viable option to achieve efficient and sensitive bolometers, with the superconductor contacts serving as hot electron barriers. For a graphene-superconductor device with highly transparent interfaces, the resistance readout in the presence of radio frequency radiation is dominated by non-linear response. On the other hand, a graphene-superconductor tunnel device shows dominantly bolometric response to radiation. For graphene devices fabricated on SiO{sub 2} substrates, we confirm recent theoretical predictions of T{sup 2} temperature dependence of phonon thermal conductance in the presence of disorder in the graphene channel at low temperatures.

  6. Thermal conductivity of the electrode gap of a therminonic converter, filled with inert gases, at low pressures

    SciTech Connect (OSTI)

    Modin, V.A.; Nikolaev, Y.V.

    1986-05-01T23:59:59.000Z

    This paper presents experimental data on the thermal conductivity of the electrode gap of a thermionic converter filled with He, Ar, and Xe in the pessure range 40-550 Pa. The need to account for the coefficients of thermal accomodation of the emitter-inert-gas-collector system in this range is shown. The accomodation coefficients for different temperature regimes are measured and expressions are obtained to calculate the heat flux transported by the inert gases in the electrode gap. A diagram of the experimental thermionic converter is shown.

  7. Title COMBINATION OF THERMAL SOLAR COLLECTORS, HEAT PUMP AND THERMAL ENERGY STORAGE FOR DWELLINGS IN BELGIUM.

    E-Print Network [OSTI]

    Contact Raf; De Herdt; Roel De Coninck; Filip Van Den Schoor; Lieve Helsen

    The amount of available solar energy in Belgium is more than sufficient to meet local heat demand for space heating and domestic hot water in a dwelling. However, the timing of both the availability of solar energy and the need for thermal energy, match only to a limited extent. Therefore, compact storage of the surplus of thermal energy is a critical issue. Depending on the temperature at which this energy is available, directly from the sun or indirectly through the storage, different combinations with a heat pump can be considered. By combining solar energy with a heat pump one may benefit on both sides since the fraction of solar energy increases as well as the performance of the heat pump. The aim of this thesis is to select the best out of three configurations that combine thermal solar collectors, heat pump and thermal energy storage for heating purposes in dwellings in Belgium, based on model simulations. Energetic, exergetic and economic criteria are used to evaluate the different configurations, while thermal comfort and domestic hot water tap profiles should be met. One (or more) performance index (indices) is (are) defined enabling an objective comparison between different systems. Today several systems are already commercially available on the international market [4]. Since these systems consist of different components, the system design is a crucial issue. Therefore, special attention should be paid to the sizing of the individual components, the interaction of the components within the global system, and the strategy for operational control. To study the interaction with the building, three types of buildings (already defined in a previous project) are considered.

  8. Phonon Heat Conduction in Corrugated Silicon Nanowires Below the Casimir Limit Christophe Blanc,1

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    very low thermal conductances of highly rough silicon nanowires [7, 18], far below the amorphous limit, 2013) The thermal conductance of straight and corrugated monocrystalline silicon nanowires has been of nanostructured materials or low dimen- sional materials has attracted growing interest [1­4], es- pecially

  9. The simple boundary element method for transient heat conduction in functionally graded materials

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    of functional material variation (quadratic, exponential and trigonometric) of thermal conductivity and specific, in an FGM, one face of a structural component is an engineering ceramic that can resist severe thermal ceramic and fracture- resisting metal can improve the properties of thermal barrier systems because

  10. Thermal characterization of submicron polyacrylonitrile fibers based on optical heating and electrical thermal sensing

    SciTech Connect (OSTI)

    Hou Jinbo; Wang Xinwei; Zhang Lijun [Department of Mechanical Engineering, N104 Walter Scott Engineering Center, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0656 (United States)

    2006-10-09T23:59:59.000Z

    In this work, the thermal diffusivity of single submicron ({approx}800 nm) polyacrylonitrile (PAN) fibers is characterized using the recently developed optical heating and electrical thermal sensing technique. In the experiment, a thin Au film (approximately in the nanometer range) is coated on the surface of nonconductive PAN fibers. A periodically modulated laser beam is used to irradiate suspended individual fibers to achieve noncontact periodical heating. The periodical temperature response of the sample is monitored by measuring the electrical resistance variation of the thin Au coating. The experimental results for three different synthesized PAN fibers with varying Au coating thickness are presented and discussed.

  11. Thermal Conductivity of Cubic and Hexagonal Mesoporous Silica Thin Films

    E-Print Network [OSTI]

    Coquil, Thomas; Richman, Eric K.; Hutchinson, Neal J.; Tolbert, S H; Pilon, Laurent

    2009-01-01T23:59:59.000Z

    wire, serving as both a thermometer and a line heat source,as both heater and thermometer, was patterned on (A) (B)Diff Amp B Diff Amp Heater/thermometer on the sample I + V -

  12. Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Window Frames

    E-Print Network [OSTI]

    1 Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer Arasteh and Dragan Curcija ABSTRACT Accurately analyzing heat transfer in window frame cavities radiation heat-transfer effects.) We examine three representative complex cavity cross-section profiles

  13. COYOTE : a finite element computer program for nonlinear heat conduction problems. Part I, theoretical background.

    SciTech Connect (OSTI)

    Glass, Micheal W.; Hogan, Roy E., Jr.; Gartling, David K.

    2010-03-01T23:59:59.000Z

    The need for the engineering analysis of systems in which the transport of thermal energy occurs primarily through a conduction process is a common situation. For all but the simplest geometries and boundary conditions, analytic solutions to heat conduction problems are unavailable, thus forcing the analyst to call upon some type of approximate numerical procedure. A wide variety of numerical packages currently exist for such applications, ranging in sophistication from the large, general purpose, commercial codes, such as COMSOL, COSMOSWorks, ABAQUS and TSS to codes written by individuals for specific problem applications. The original purpose for developing the finite element code described here, COYOTE, was to bridge the gap between the complex commercial codes and the more simplistic, individual application programs. COYOTE was designed to treat most of the standard conduction problems of interest with a user-oriented input structure and format that was easily learned and remembered. Because of its architecture, the code has also proved useful for research in numerical algorithms and development of thermal analysis capabilities. This general philosophy has been retained in the current version of the program, COYOTE, Version 5.0, though the capabilities of the code have been significantly expanded. A major change in the code is its availability on parallel computer architectures and the increase in problem complexity and size that this implies. The present document describes the theoretical and numerical background for the COYOTE program. This volume is intended as a background document for the user's manual. Potential users of COYOTE are encouraged to become familiar with the present report and the simple example analyses reported in before using the program. The theoretical and numerical background for the finite element computer program, COYOTE, is presented in detail. COYOTE is designed for the multi-dimensional analysis of nonlinear heat conduction problems. A general description of the boundary value problems treated by the program is presented. The finite element formulation and the associated numerical methods used in COYOTE are also outlined. Instructions for use of the code are documented in SAND2010-0714.

  14. A two-fluid model for relativistic heat conduction

    SciTech Connect (OSTI)

    López-Monsalvo, César S. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México (Mexico)

    2014-01-14T23:59:59.000Z

    Three years ago it was presented in these proceedings the relativistic dynamics of a multi-fluid system together with various applications to a set of topical problems [1]. In this talk, I will start from such dynamics and present a covariant formulation of relativistic thermodynamics which provides us with a causal constitutive equation for the propagation of heat in a relativistic setting.

  15. Computational analysis of the thermal conductivity of the carboncarbon composite materials

    E-Print Network [OSTI]

    Grujicic, Mica

    Computational analysis of the thermal conductivity of the carbon­carbon composite materials M Abstract Experimental data for carbon­carbon con- stituent materials are combined with a three and longitudinal thermal conductivities in carbon­carbon composites. Particular attention is given in elucidating

  16. Thermal conductivity of nitrogenated ultrananocrystalline diamond films M. Shamsa,1,a

    E-Print Network [OSTI]

    , polycrystalline diamond PCD , diamondlike carbon DLC , carbon nanotubes, and single-layer graphene, have recentlyThermal conductivity of nitrogenated ultrananocrystalline diamond films on silicon M. Shamsa,1,a S of nitrogenated ultrananocrystalline diamond UNCD films on silicon. For better accuracy, the thermal conductivity

  17. ENHANCED THERMAL CONDUCTIVITY IN NANOFLUIDS UNDER THE ACTION OF OSCILLATING FORCE FIELDS

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . Active control of transport coefficients. Nanocolloïds. Cooling system Introduction Nanofluids (EastmanENHANCED THERMAL CONDUCTIVITY IN NANOFLUIDS UNDER THE ACTION OF OSCILLATING FORCE FIELDS Clément Le forces in the radio frequency and microwave ranges, we show that the thermal conductivity of nanofluids

  18. Sound Waves, Thermal Conduction, and the Continuity Equation Carl Sovinec, T-15 LANL

    E-Print Network [OSTI]

    Sovinec, Carl

    Sound Waves, Thermal Conduction, and the Continuity Equation Carl Sovinec, T-15 LANL 8 to sound waves when we use thermal conduction in our system of equations without continuity. The fluid definitions 0 02 p c , defining c as the adiabatic sound speed, kc 1 , the time for the adiabatic wave

  19. Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies of Percolation of Microemulsions

    E-Print Network [OSTI]

    Reid, Scott A.

    Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies studied below and above the percolation thresholds by electrical conductivity, near-infrared absorption. In this work the structure of microemulsions was investigated by using the near-IR absorption and thermal lens

  20. Study of thermal conductivity in organic solid wastes before composting J. HUET, C. Druilhe, G. Debenest

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Study of thermal conductivity in organic solid wastes before composting J. HUET, C. Druilhe, G. Debenest ORBIT2012 1 STUDY OF THERMAL CONDUCTIVITY IN ORGANIC SOLID WASTES BEFORE COMPOSTING J. Huet, as illustrated by current EU waste policy and its five main priorities: prevention, reuse, recycling, recovery

  1. Thermal conductance of metal-diamond interfaces at high pressure Gregory T. Hohensee

    E-Print Network [OSTI]

    Cahill, David G.

    are concerned with the exchange of thermal energy across an interface between two materials. This topic-nonmetal interface, a two-temperature model predicts a thermal resistance of Rep = 1/ gL in series with the phononThermal conductance of metal-diamond interfaces at high pressure Gregory T. Hohensee Department

  2. Generalized model of thermal boundary conductance between SWNT and surrounding supercritical Lennard-Jones fluid

    E-Print Network [OSTI]

    Maruyama, Shigeo

    of the promising applications is to use SWNTs as additives to enhance thermal conductivity of composite materials of the composite can be strongly influenced by thermal boundary resistance (TBR) between carbon nanotubes, it is essential to understand TBR. Thermal boundary resistance, with its importance in small scale, has been

  3. Thermal performance of direct contact heat exchangers for mixed hydrocarbons

    SciTech Connect (OSTI)

    Sharpe, L. Jr.; Coswami, D.Y.; Demuth, O.J.; Mines, G.

    1985-01-01T23:59:59.000Z

    This paper describes a physical and a mathematical model for evaluating the tray efficiencies for a direct contact heat exchanger (DCHX). The model is then used to determine the efficiencies for tests conducted on a 60kW sieve tray DCHX as heat is transferred from a geofluid (brine) to a working fluid (mixed hydrocarbons). It is assumed that there are three distinct regions in the column based on the state of the working fluid, as follows: Region I - Preheating with no vaporization; Region II - Preheating with moderate vaporization; and Region III - Major vaporization. The boundaries of these regions can be determined from the experimental data. In the model, mass balance and energy balance is written for a tray ''N'' in each of these regions. Finally, the ''tray efficiency'' or ''heat transfer'' effectiveness of the tray is calculated based on the definition that it is the ratio of the actual heat transfer to the maximum possible, thermodynamically.

  4. Communication: Minimum in the thermal conductivity of supercooled water: A computer simulation study

    SciTech Connect (OSTI)

    Bresme, F., E-mail: f.bresme@imperial.ac.uk [Chemical Physics Section, Department of Chemistry, Imperial College, London SW7 2AZ, United Kingdom and Department of Chemistry, Norwegian University of Science and Technology, Trondheim 7491 (Norway); Biddle, J. W.; Sengers, J. V.; Anisimov, M. A. [Institute for Physical Science and Technology, and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)] [Institute for Physical Science and Technology, and Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2014-04-28T23:59:59.000Z

    We report the results of a computer simulation study of the thermodynamic properties and the thermal conductivity of supercooled water as a function of pressure and temperature using the TIP4P-2005 water model. The thermodynamic properties can be represented by a two-structure equation of state consistent with the presence of a liquid-liquid critical point in the supercooled region. Our simulations confirm the presence of a minimum in the thermal conductivity, not only at atmospheric pressure, as previously found for the TIP5P water model, but also at elevated pressures. This anomalous behavior of the thermal conductivity of supercooled water appears to be related to the maximum of the isothermal compressibility or the minimum of the speed of sound. However, the magnitudes of the simulated thermal conductivities are sensitive to the water model adopted and appear to be significantly larger than the experimental thermal conductivities of real water at low temperatures.

  5. The Role of Thermal Conduction in Tearing Mode Theory

    E-Print Network [OSTI]

    Connor, J W; Hastie, R J; Liu, Y Q

    2014-01-01T23:59:59.000Z

    The role of anisotropic thermal diffusivity on tearing mode stability is analysed in general toroidal geometry. A dispersion relation linking the growth rate to the tearing mode stability parameter, Delta, is derived. By using a resistive MHD code, modified to include such thermal transport, to calculate tearing mode growth rates, the dispersion relation is employed to determine Delta in situations with finite plasma pressure that are stabilised by favourable average curvature in a simple resistive MHD model. We also demonstrate that the same code can also be used to calculate the basis-functions [C J Ham, et al, Plasma Phys. Control. Fusion 54 (2012) 105014] needed to construct Delta.

  6. Innovative Miniaturized Heat Pumps for Buildings: Modular Thermal Hub for Building Heating, Cooling and Water Heating

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    BEETIT Project: Georgia Tech is using innovative components and system design to develop a new type of absorption heat pump. Georgia Tech’s new heat pumps are energy efficient, use refrigerants that do not emit greenhouse gases, and can run on energy from combustion, waste heat, or solar energy. Georgia Tech is leveraging enhancements to heat and mass transfer technology possible in microscale passages and removing hurdles to the use of heat-activated heat pumps that have existed for more than a century. Use of microscale passages allows for miniaturization of systems that can be packed as monolithic full-system packages or discrete, distributed components enabling integration into a variety of residential and commercial buildings. Compared to conventional heat pumps, Georgia Tech’s design innovations will create an absorption heat pump that is much smaller, has higher energy efficiency, and can also be mass produced at a lower cost and assembly time.

  7. Thermal conductivity changes upon neutron transmutation of {sup 10}B doped diamond

    SciTech Connect (OSTI)

    Jagannadham, K., E-mail: jag-kasichainula@ncsu.edu [Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Verghese, K. [Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Butler, J. E. [Code 6174, Naval research Laboratory, Washington, District of Columbia 20375 (United States)

    2014-08-28T23:59:59.000Z

    {sup 10}B doped p-type diamond samples were subjected to neutron transmutation reaction using thermal neutron flux of 0.9 × 10{sup 13} cm{sup ?2} s{sup ?1} and fast neutron flux of 0.09 × 10{sup 13} cm{sup ?2} s{sup ?1}. Another sample of epilayer grown on type IIa (110) single crystal diamond substrate was subjected to equal thermal and fast neutron flux of 10{sup 14}?cm{sup ?2} s{sup ?1}. The defects in the diamond samples were previously characterized by different methods. In the present work, thermal conductivity of these diamond samples was determined at room temperature by transient thermoreflectance method. The thermal conductivity change in the samples as a function of neutron fluence is explained by the phonon scattering from the point defects and disordered regions. The thermal conductivity of the diamond samples decreased more rapidly initially and less rapidly for larger neutron fluence. In addition, the thermal conductivity in type IIb diamond decreased less rapidly with thermal neutron fluence compared to the decrease in type IIa diamond subjected to fast neutron fluence. It is concluded that the rate of production of defects during transmutation reaction is slower when thermal neutrons are used. The thermal conductivity of epilayer of diamond subjected to high thermal and fast neutron fluence is associated with the covalent carbon network in the composite structure consisting of disordered carbon and sp{sup 2} bonded nanocrystalline regions.

  8. Assessment and Prediction of the Thermal Performance of a Centralized Latent Heat Thermal Energy Storage Utilizing Artificial Neural Network

    E-Print Network [OSTI]

    El-Sawi, A.; Haghighat, F.; Akbari, H.

    2013-01-01T23:59:59.000Z

    A simulation tool is developed to analyze the thermal performance of a centralized latent heat thermal energy storage system (LHTES) using computational fluid dynamics (CFD). The LHTES system is integrated with a mechanical ventilation system...

  9. Efficient Heat Storage Materials: Metallic Composites Phase-Change Materials for High-Temperature Thermal Energy Storage

    SciTech Connect (OSTI)

    None

    2011-11-21T23:59:59.000Z

    HEATS Project: MIT is developing efficient heat storage materials for use in solar and nuclear power plants. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun’s not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. MIT is designing nanostructured heat storage materials that can store a large amount of heat per unit mass and volume. To do this, MIT is using phase change materials, which absorb a large amount of latent heat to melt from solid to liquid. MIT’s heat storage materials are designed to melt at high temperatures and conduct heat well—this makes them efficient at storing and releasing heat and enhances the overall efficiency of the thermal storage and energy-generation process. MIT’s low-cost heat storage materials also have a long life cycle, which further enhances their efficiency.

  10. Heat conductivity in the beta-FPU lattice. Solitons and breathers as energy carriers

    E-Print Network [OSTI]

    T. Yu. Astakhova; V. N. Likhachev; G. A. Vinogradov

    2011-03-18T23:59:59.000Z

    This paper consists of two parts. The first part proposes a new methodological framework within which the heat conductivity in 1D lattices can be studied. The total process of heat conductivity is decomposed into two contributions where the first one is the equilibrium process at equal temperatures T of both lattice ends and the second -- non-equilibrium process with the temperature \\Delta T of one end and zero temperature of the other. The heat conductivity in the limit \\Delta T \\to 0 is reduced to the heat conductivity of harmonic lattice. A threshold temperature T_{thr} scales T_{thr}(N) \\sim N^{-3} with the lattice size N. Some unusual properties of heat conductivity can be exhibited on nanoscales at low temperatures. The thermodynamics of the \\beta-FPU lattice can be adequately approximated by the harmonic lattice. The second part testifies in the favor of the soliton and breather contribution to the heat conductivity in contrast to [N. Li, B. Li, S. Flach, PRL 105 (2010) 054102]. In the continuum limit the \\beta-FPU lattice is reduced to the modified Korteweg - de Vries equation with soliton and breather solutions. Numerical simulations demonstrate their high stability. New method for the visualization of moving solitons and breathers is suggested. An accurate expression for the dependence of the sound velocity on temperature is also obtained. Our results support the conjecture on the solitons and breathers contribution to the heat conductivity.

  11. Glass-like thermal conductivity in high efficiency thermoelectric materials

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious Rank EERE:YearRound-UpHeatMulti-Dimensional Subject: Guidance forGeospatialSession) |GettingLEARNINGGive|

  12. Tables for solution of the heat-conduction equation with a time-dependent heating rate

    E-Print Network [OSTI]

    Bergles A. E.

    1962-01-01T23:59:59.000Z

    Tables are presented for the solution of the transient onedimensional heat flow in a solid body of constant material properties with the heating rate at one boundary dependent on time. These tables allow convenient and ...

  13. THERMAL CONDUCTIVITY OF AQUEOUS NaCl SOLUTIONS

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystallineForeign Object DamageSystemsU.S. TALKS1THE WHITE 9086 THERMAL

  14. Determination of thermal accommodation coefficients from heat transfer measurements between parallel plates.

    SciTech Connect (OSTI)

    Gallis, Michail A.; Castaneda, Jaime N.; Rader, Daniel John; Torczynski, John Robert; Trott, Wayne Merle

    2010-10-01T23:59:59.000Z

    Thermal accommodation coefficients have been derived for a variety of gas-surface combinations using an experimental apparatus developed to measure the pressure dependence of the conductive heat flux between parallel plates at unequal temperature separated by a gas-filled gap. The heat flux is inferred from temperature-difference measurements across the plates in a configuration where the plate temperatures are set with two carefully controlled thermal baths. Temperature-controlled shrouds provide for environmental isolation of the opposing test plates. Since the measured temperature differences in these experiments are very small (typically 0.3 C or less over the entire pressure range), high-precision thermistors are used to acquire the requisite temperature data. High-precision components have also been utilized on the other control and measurement subsystems in this apparatus, including system pressure, gas flow rate, plate alignment, and plate positions. The apparatus also includes the capability for in situ plasma cleaning of the installed test plates. Measured heat-flux results are used in a formula based on Direct Simulation Monte Carlo (DSMC) code calculations to determine the thermal accommodation coefficients. Thermal accommodation coefficients have been determined for three different gases (argon, nitrogen, helium) in contact with various surfaces. Materials include metals and alloys such as aluminum, gold, platinum, and 304 stainless steel. A number of materials important to fabrication of Micro Electro Mechanical Systems (MEMS) devices have also been examined. For most surfaces, coefficient values are near 0.95, 0.85, and 0.45 for argon, nitrogen, and helium, respectively. Only slight differences in accommodation as a function of surface roughness have been seen. Surface contamination appears to have a more significant effect: argon plasma treatment has been observed to reduce thermal accommodation by as much as 0.10 for helium. Mixtures of argon and helium have also been examined, and the results have been compared to DSMC simulations incorporating thermal-accommodation values from single-species experiments.

  15. TOPAZ2D heat transfer code users manual and thermal property data base

    SciTech Connect (OSTI)

    Shapiro, A.B.; Edwards, A.L.

    1990-05-01T23:59:59.000Z

    TOPAZ2D is a two dimensional implicit finite element computer code for heat transfer analysis. This user's manual provides information on the structure of a TOPAZ2D input file. Also included is a material thermal property data base. This manual is supplemented with The TOPAZ2D Theoretical Manual and the TOPAZ2D Verification Manual. TOPAZ2D has been implemented on the CRAY, SUN, and VAX computers. TOPAZ2D can be used to solve for the steady state or transient temperature field on two dimensional planar or axisymmetric geometries. Material properties may be temperature dependent and either isotropic or orthotropic. A variety of time and temperature dependent boundary conditions can be specified including temperature, flux, convection, and radiation. Time or temperature dependent internal heat generation can be defined locally be element or globally by material. TOPAZ2D can solve problems of diffuse and specular band radiation in an enclosure coupled with conduction in material surrounding the enclosure. Additional features include thermally controlled reactive chemical mixtures, thermal contact resistance across an interface, bulk fluid flow, phase change, and energy balances. Thermal stresses can be calculated using the solid mechanics code NIKE2D which reads the temperature state data calculated by TOPAZ2D. A three dimensional version of the code, TOPAZ3D is available. The material thermal property data base, Chapter 4, included in this manual was originally published in 1969 by Art Edwards for use with his TRUMP finite difference heat transfer code. The format of the data has been altered to be compatible with TOPAZ2D. Bob Bailey is responsible for adding the high explosive thermal property data.

  16. The Added Economic and Environmental Value of Solar Thermal Systems in Microgrids with Combined Heat and Power

    E-Print Network [OSTI]

    Marnay, Chris

    2010-01-01T23:59:59.000Z

    Environmental Value of Solar Thermal Systems in MicrogridsEnvironmental Value of Solar Thermal Systems in Microgridsa) ABSTRACT The addition of solar thermal and heat storage

  17. Electron-Phonon Coupling and Thermal Conductance at a Metal-Semiconductor Interface: First-principles Analysis

    E-Print Network [OSTI]

    Sadasivam, Sridhar; Fisher, Timothy S

    2015-01-01T23:59:59.000Z

    The mechanism of heat transfer and the contribution of electron-phonon coupling to thermal conductance of a metal-semiconductor interface remains unclear in the present literature. We report ab initio simulations of a technologically important titanium silicide (metal) - silicon (semiconductor) interface to estimate the Schottky barrier height (SBH), and the strength of electron-phonon and phonon-phonon heat transfer across the interface. The electron and phonon dispersion relations of TiSi$_2$ with C49 structure and the TiSi$_2$-Si interface are obtained using first-principles calculations within the density functional theory (DFT) framework. These are used to estimate electron-phonon linewidths and the associated Eliashberg function that quantifies coupling. We show that the coupling strength of electrons with interfacial phonon modes is of the same order of magnitude as coupling of electrons to phonon modes in the bulk metal, and its contribution to electron-phonon interfacial conductance is comparable to ...

  18. Anomalous heat conduction in polyethylene chains: Theory and molecular dynamics simulations

    E-Print Network [OSTI]

    Henry, Asegun

    In 1955 Fermi, Pasta, and Ulam showed that a simple model for a nonlinear one-dimensional chain of particles can be nonergodic, which implied infinite thermal conductivity. A more recent investigation of a realistic model ...

  19. Microstructure and thermal conductivity of surfactant-free NiO nanostructures

    SciTech Connect (OSTI)

    Sahoo, Pranati [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Misra, Dinesh K. [The Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Salvador, Jim [Chemical Sciences and Materials Systems Laboratory, General Motors R and D Center, Warren, MI 48090 (United States); Makongo, Julien P.A. [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Chaubey, Girija S. [Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Takas, Nathan J. [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Wiley, John B. [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States); Poudeu, Pierre F.P., E-mail: ppoudeup@umich.edu [Laboratory for Emerging Energy and Electronic Materials, Materials Science and Engineering Department, University of Michigan, Ann Arbor, MI 48109 (United States); Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Advanced Materials Research Institute, University of New Orleans, New Orleans, LA 70148 (United States)

    2012-06-15T23:59:59.000Z

    High purity, nanometer sized surfactant-free nickel oxide (NiO) particles were produced in gram scale using a solution combustion method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), gas pycnometry and gas adsorption analysis (BET). The average particle size of the as-synthesized NiO increases significantly with the preheating temperature of the furnace, while the specific surface area decreases. A BET specific surface area of {approx}100 m{sup 2}/g was obtained for NiO nanoparticles with size as small as 3 nm synthesized at 300 Degree-Sign C. The thermal conductivity ({kappa}) of pressed pellets of the synthesized NiO nanoparticles obtained using spark plasma sintering (SPS) and uniaxial hot pressing is drastically decreased ({approx}60%) compared to that of NiO single crystal. This strong reduction in {kappa} with particle size suggests the suitability of the synthesized surfactant-free NiO nanoparticles for use as nanoinclusions when designing high performance materials for waste heat recovery. - Graphical abstract: Highly efficient phonon scattering by surfactant-free NiO nanostructures obtained by solution combustion of a mixture of nickel (II) nitrate hexahydrate (oxidizer) and urea (fuel) at various temperatures. Highlights: Black-Right-Pointing-Pointer Fast synthesis of surfactant-free NiO nanoparticles with controllable size. Black-Right-Pointing-Pointer High specific surface area for NiO nanoparticles with size range from 3 to 7 nm. Black-Right-Pointing-Pointer Strong reduction of the thermal conductivity with decreasing particle size. Black-Right-Pointing-Pointer NiO as nanoinclusions in high performance materials for energy conversion.

  20. Theoretical investigation of the impact of grain boundaries and fission gases on UO2 thermal conductivity

    SciTech Connect (OSTI)

    Du, Shiyu [Los Alamos National Laboratory; Andersson, Anders D. [Los Alamos National Laboratory; Germann, Timothy C. [Los Alamos National Laboratory; Stanek, Christopher R. [Los Alamos National Laboratory

    2012-05-02T23:59:59.000Z

    Thermal conductivity is one of the most important metrics of nuclear fuel performance. Therefore, it is crucial to understand the impact of microstructure features on thermal conductivity, especially since the microstructure evolves with burn-up or time in the reactor. For example, UO{sub 2} fuels are polycrystalline and for high-burnup fuels the outer parts of the pellet experience grain sub-division leading to a very fine grain structure. This is known to impact important physical properties such as thermal conductivity as fission gas release. In a previous study, we calculated the effect of different types of {Sigma}5 grain boundaries on UO{sub 2} thermal conductivity and predicted the corresponding Kapitza resistances, i.e. the resistance of the grain boundary in relation to the bulk thermal resistance. There have been reports of pseudoanisotropic effects for the thermal conductivity in cubic polycrystalline materials, as obtained from molecular dynamics simulations, which means that the conductivity appears to be a function of the crystallographic direction of the temperature gradient. However, materials with cubic symmetry should have isotropic thermal conductivity. For this reason it is necessary to determine the cause of this apparent anisotropy and in this report we investigate this effect in context of our earlier simulations of UO{sub 2} Kapitza resistances. Another source of thermal resistance comes from fission products and fission gases. Xe is the main fission gas and when generated in sufficient quantity it dissolves from the lattice and forms gas bubbles inside the crystalline structure. We have performed studies of how Xe atoms dissolved in the UO{sub 2} matrix or precipitated as bubbles impact thermal conductivity, both in bulk UO{sub 2} and in the presence of grain boundaries.

  1. Shutdown heat removal system reliability in thermal reactors

    SciTech Connect (OSTI)

    Sun, Y.H.; Bari, R.A.

    1980-01-01T23:59:59.000Z

    An analysis of the failure probability per year of the shutdown heat removal system (SHRS) at hot standby conditions for two thermal reactor designs is presented. The selected reactor designs are the Pressurized Water Reactor and the Nonproliferation Alternative System Assessment Program Heavy Water Reactor. Failures of the SHRS following the initiating transients of loss of offsite power and loss of main feedwater system are evaluated. Common mode failures between components are incorporated in this anlaysis via the ..beta..-factor method and the sensitivity of the system reliability to common mode failures is investigated parametrically.

  2. 1.12.2014bo Akademi Univ -Thermal and Flow Engineering Piispankatu 8, 20500 Turku 1/24 8. Heat pumps, heat pipes,

    E-Print Network [OSTI]

    Zevenhoven, Ron

    pumps, heat pipes, cold thermal energy storage Ron Zevenhoven Ã?bo Akademi University Thermal and Flow for heating is referred to as a heat pump (mostly based on a vapour-compression cycle) Heat pumps make use electricity!) for heating and air conditioning purposes Heat pumps became popular in the 1970s

  3. Thermal Energy Corporation Combined Heat and Power Project

    SciTech Connect (OSTI)

    E. Bruce Turner; Tim Brown; Ed Mardiat

    2011-12-31T23:59:59.000Z

    To meet the planned heating and cooling load growth at the Texas Medical Center (TMC), Thermal Energy Corporation (TECO) implemented Phase 1 of a Master Plan to install an additional 32,000 tons of chilled water capacity, a 75,000 ton-hour (8.8 million gallon) Thermal Energy Storage (TES) tank, and a 48 MW Combined Heat and Power (CHP) system. The Department of Energy selected TMC for a $10 million grant award as part of the Financial Assistance Funding Opportunity Announcement, U.S. Department of Energy National Energy Technology, Recovery Act: Deployment of Combined Heat and Power (CHP) Systems, District Energy Systems, Waste Energy Recovery Systems, and Efficiency Industrial Equipment Funding Opportunity Number: DE-FOA-0000044 to support the installation of a new 48 MW CHP system at the TMC located just outside downtown Houston. As the largest medical center in the world, TMC is home to many of the nationâ??s best hospitals, physicians, researchers, educational institutions, and health care providers. TMC provides care to approximately six million patients each year, and medical instruction to over 71,000 students. A medical center the size of TMC has enormous electricity and thermal energy demands to help it carry out its mission. Reliable, high-quality steam and chilled water are of utmost importance to the operations of its many facilities. For example, advanced medical equipment, laboratories, laundry facilities, space heating and cooling all rely on the generation of heat and power. As result of this project TECO provides this mission critical heating and cooling to TMC utilizing a system that is both energy-efficient and reliable since it provides the capability to run on power independent of the already strained regional electric grid. This allows the medical center to focus on its primary mission â?? providing top quality medical care and instruction â?? without worrying about excessive energy costs or the loss of heating and cooling due to the risk of power outages. TECOâ??s operation is the largest Chilled Water District Energy System in the United States. The company used DOEâ??s funding to help install a new high efficiency CHP system consisting of a Combustion Turbine and a Heat Recovery Steam Generator. This CHP installation was just part of a larger project undertaken by TECO to ensure that it can continue to meet TMCâ??s growing needs. The complete efficiency overhaul that TECO undertook supported more than 1,000 direct and indirect jobs in manufacturing, engineering, and construction, with approximately 400 of those being jobs directly associated with construction of the combined heat and power plant. This showcase industrial scale CHP project, serving a critical component of the nationâ??s healthcare infrastructure, directly and immediately supported the energy efficiency and job creation goals established by ARRA and DOE. It also provided an unsurpassed model of a district energy CHP application that can be replicated within other energy intensive applications in the industrial, institutional and commercial sectors.

  4. 1D-to-3D transition of phonon heat conduction in polyethylene using molecular dynamics simulations

    E-Print Network [OSTI]

    Henry, Asegun

    The thermal conductivity of nanostructures generally decreases with decreasing size because of classical size effects. The axial thermal conductivity of polymer chain lattices, however, can exhibit the opposite trend, ...

  5. Assessing the Thermal Environmental Impacts of an Groundwater Heat Pump in Southeastern Washington State

    SciTech Connect (OSTI)

    Freedman, Vicky L.; Waichler, Scott R.; Mackley, Rob D.; Horner, Jacob A.

    2012-04-01T23:59:59.000Z

    A thermal analysis of a large-scale (e.g., 1900 gpm), open-loop ground source heat pump (GSHP) installed on the Pacific Northwest National Laboratory (PNNL) campus in southeastern Washington State has been performed using a numerical modeling approach. Water temperature increases at the upgradient extraction wells in the system and at the downgradient Columbia River are potential concerns, especially since heat rejection to the subsurface will occur year-round. Hence, thermal impacts of the open-loop GSHP were investigated to identify operational scenarios that minimized downgradient environmental impacts at the river, and upgradient temperature drift at the production wells. Simulations examined the sensitivity of the system to variations in pumping rates and injected water temperatures, as well as to hydraulic conductivity estimates of the aquifer. Results demonstrated that both downgradient and upgradient thermal impacts were more sensitive to injection flow rates than estimates of hydraulic conductivity. Higher injection rates at lower temperatures resulted in higher temperature increases at the extraction wells but lower increases at the river. Conversely, lower pumping rates and higher injected water temperatures resulted in a smaller temperature increase at the extraction wells, but higher increases at the river. The scenario with lower pumping rates is operationally more efficient, but does increase the likelihood of a thermal plume discharging into the Columbia River. However, this impact would be mitigated by mixing within the hyporheic zone and the Columbia River. The impact under current operational conditions is negligible, but future increases in heat rejection could require a compromise between maximizing operational efficiency and minimizing temperature increases at the shoreline.

  6. Thermal conductivity of fluids containing suspension of nanometer-sized particles

    E-Print Network [OSTI]

    Ma, Jack Jeinhao

    2006-01-01T23:59:59.000Z

    Nanofluids, which are fluids containing suspension of nanometer-sized particles, have been reported to possess substantially higher thermal conductivity than their respective base fluids. This thesis reports on an experimental ...

  7. Mixed ionic and electronic conducting electrode studies for an alkali metal thermal to electric converter

    E-Print Network [OSTI]

    Guo, Yuyan

    2009-05-15T23:59:59.000Z

    This research focuses on preparation, kinetics, and performance studies of mixed ionic and electronic conducting electrodes (MIEE) applied in an alkali metal thermal to electric converter (AMTEC). Two types of MIEE, metal/sodium titanate and metal...

  8. Effective thermal conductivity measurements relevant to deep borehole nuclear waste disposal

    E-Print Network [OSTI]

    Shaikh, Samina

    2007-01-01T23:59:59.000Z

    The objective of this work was to measure the effective thermal conductivity of a number of materials (particle beds, and fluids) proposed for use in and around canisters for disposal of high level nuclear waste in deep ...

  9. LARGE SCALE PERMEABILITY TEST OF THE GRANITE IN THE STRIPA MINE AND THERMAL CONDUCTIVITY TEST

    E-Print Network [OSTI]

    Lundstrom, L.

    2011-01-01T23:59:59.000Z

    No.2 LARGE SCALE PERMEABILITY TEST OF THE GRANITE' IN THEMINE AND, THERMAL CONDUCTIVITY TEST Lars Lundstrom and HakanSUMMARY REPORT Background TEST SITE Layout of test places

  10. Geometry and temperature dependent thermal conductivity of diamond nanowires: A non-equilibrium molecular dynamics study

    E-Print Network [OSTI]

    Melnik, Roderick

    plasma etching of polycrystalline diamond films [7], microwave plasma assisted chemical vapor deposition. For theoretical calculations of proper- ties of nanosized diamond materials, polycrystalline diamond thin filmsGeometry and temperature dependent thermal conductivity of diamond nanowires: A non

  11. Enhancing thermal conductivity of fluids with graphite nanoparticles and carbon nanotube

    DOE Patents [OSTI]

    Zhang, Zhiqiang (Lexington, KY); Lockwood, Frances E. (Georgetown, KY)

    2008-03-25T23:59:59.000Z

    A fluid media such as oil or water, and a selected effective amount of carbon nanomaterials necessary to enhance the thermal conductivity of the fluid. One of the preferred carbon nanomaterials is a high thermal conductivity graphite, exceeding that of the neat fluid to be dispersed therein in thermal conductivity, and ground, milled, or naturally prepared with mean particle size less than 500 nm, and preferably less than 200 nm, and most preferably less than 100 nm. The graphite is dispersed in the fluid by one or more of various methods, including ultrasonication, milling, and chemical dispersion. Carbon nanotubes with graphitic structure is another preferred source of carbon nanomaterial, although other carbon nanomaterials are acceptable. To confer long term stability, the use of one or more chemical dispersants is preferred. The thermal conductivity enhancement, compared to the fluid without carbon nanomaterial, is proportional to the amount of carbon nanomaterials (carbon nanotubes and/or graphite) added.

  12. Thermal and electrical conduction in the compaction direction of exfoliated graphite

    E-Print Network [OSTI]

    Chung, Deborah D.L.

    Thermal and electrical conduction in the compaction direction of exfoliated graphite in the compaction direction of graphite-flake-based exfoliated graphite have been decoupled. The compact Exfoliated graphite is elongated graphite particles obtained by the exfoliation (typically involving rapid

  13. Basal-plane thermal conductivity of few-layer molybdenum disulfide

    SciTech Connect (OSTI)

    Jo, Insun; Ou, Eric; Shi, Li, E-mail: lishi@mail.utexas.edu [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Pettes, Michael Thompson [Department of Mechanical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Department of Mechanical Engineering and the Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States); Wu, Wei [Department of Mechanical Engineering and the Institute of Materials Science, University of Connecticut, Storrs, Connecticut 06269 (United States)

    2014-05-19T23:59:59.000Z

    We report the in-plane thermal conductivity of suspended exfoliated few-layer molybdenum disulfide (MoS{sub 2}) samples that were measured by suspended micro-devices with integrated resistance thermometers. The obtained room-temperature thermal conductivity values are (44–50) and (48–52) W m{sup ?1} K{sup ?1} for two samples that are 4 and 7 layers thick, respectively. For both samples, the peak thermal conductivity occurs at a temperature close to 120?K, above which the thermal conductivity is dominated by intrinsic phonon-phonon scattering although phonon scattering by surface disorders can still play an important role in these samples especially at low temperatures.

  14. Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium Reduction of Polymer-

    E-Print Network [OSTI]

    Pilon, Laurent

    Thermal Conductivity of Ordered Mesoporous Nanocrystalline Silicon Thin Films Made from Magnesium-assembly of mesoporous silica followed by magnesium reduction. The periodic ordering of pores in mesoporous silicon

  15. Thermal conductivity of self-assembled nano-structured ZnO bulk ceramics

    SciTech Connect (OSTI)

    Zhao, Yu [Bio-Inspired Materials and Devices Laboraory (BMDL); Yan, Yongke [Bio-Inspired Materials and Devices Laboraory (BMDL); Kumar, Ashok [Bio-Inspired Materials and Devices Laboraory (BMDL); Wang, Hsin [ORNL; Porter, Wallace D [ORNL

    2012-01-01T23:59:59.000Z

    In this study, we describe the changes in thermal conductivity behavior of ZnO-Al micro- and nano-two-phase self-assembled composites with varying grain sizes. The reduction in thermal conductivity values of micro-composites was limited to {approx}15% for ZnO-4% Al. However, nano-composites exhibited large reduction, by a factor of about three, due to uniform distribution of nano-precipitates (ZnAl2O4) and large grain boundary area. Interestingly, the micro-composites revealed continuous decrease in thermal conductivity with increase in Al substitution while the nano-composites exhibited the lowest magnitudes for 2% Al concentration. Raman spectra indicated that phonon confinement in ZnO-Al nano-composites causes drastic decrease in the value of thermal conductivity.

  16. The effect of thermal contact resistance on heat management in the electronic packaging

    E-Print Network [OSTI]

    Grujicic, Mica

    The effect of thermal contact resistance on heat management in the electronic packaging M. Grujicic the role of thermal contact resistance on heat management within a simple central processing unit (CPU interface materials on the maximum temperature experienced by the CPU. Two classes of thermal interface

  17. Thermal protection apparatus

    DOE Patents [OSTI]

    Bennett, G.A.; Elder, M.G.; Kemme, J.E.

    1984-03-20T23:59:59.000Z

    The disclosure is directed to an apparatus for thermally protecting sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components such as electronics to a heat sink such as ice.

  18. Thermal protection apparatus

    DOE Patents [OSTI]

    Bennett, Gloria A. (Los Alamos, NM); Elder, Michael G. (Los Alamos, NM); Kemme, Joseph E. (Albuquerque, NM)

    1985-01-01T23:59:59.000Z

    An apparatus which thermally protects sensitive components in tools used in a geothermal borehole. The apparatus comprises a Dewar within a housing. The Dewar contains heat pipes such as brass heat pipes for thermally conducting heat from heat sensitive components to a heat sink such as ice.

  19. Thermal Conductivity Reduction and Thermoelectric Figure of Merit Increase by Embedding Nanoparticles in Crystalline Semiconductors

    E-Print Network [OSTI]

    on the thermoelectric figure of merit (ZT) of a material defined as ZT S2 T=k, where S, , k, and T are the Seebeck by nanostructuring thermoelectric materials, and the key reason for increase in ZT was the reduction of thermalThermal Conductivity Reduction and Thermoelectric Figure of Merit Increase by Embedding

  20. Propagation of three--dimensional Alfv'en waves in a stratified, thermally conducting solar wind

    E-Print Network [OSTI]

    Propagation of three--dimensional Alfv'en waves in a stratified, thermally conducting solar wind S to the well--known thermal expansion of the solar corona [Parker, 1958, 1963, 1991]. In particular Alfv'en waves in the solar atmosphere and wind, taking into account relevant physical effects

  1. Measurement of Thermal Conductivity of PbTe Nanocrystal Coated Glass Fibers by the 3 Method

    E-Print Network [OSTI]

    Ruan, Xiulin

    and high aspect ratio result in a significant thermal radiation effect. We simulate the experiment using such as automobile exhaust pipes, power plant steam pipes, manufacturing industry cooling pipes, and so forth. Our the radiation effect and extract the thermal conductivity at the single fiber level. Our simulation method

  2. MAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS

    E-Print Network [OSTI]

    Chang, Ho-Myung

    -cooling with a closed-cycle refrigerator is an excellent option for relatively small superconducting systems. Since to energy consumption, mainly because the thermal loss associated with the storage and the transferMAGNET/CRYOCOOLER INTEGRATIONFOR THERMAL STABILITY IN CONDUCTION-COOLED SYSTEMS H.-M. Chang and K

  3. Journal of Power Sources 161 (2006) 11061115 Direct measurement of through-plane thermal conductivity and

    E-Print Network [OSTI]

    Mench, Matthew M.

    conductivity and contact resistance in fuel cell materials Manish Khandelwal, M.M. Mench Fuel Cell Dynamics, and the thermal contact resistance between diffusion media and a metal plate as a function of temperature® membrane; Diffusion media; Thermal contact resistance 1. Introduction Detailed knowledge of the internal

  4. Size-dependent interface phonon transmission and thermal conductivity of nanolaminates

    E-Print Network [OSTI]

    Li, Baowen

    resistance between different materials exists since the interface breaks the regular lattice structure and superlattices as the interface distance or periodic thickness reduces. The interface thermal resistance has beenSize-dependent interface phonon transmission and thermal conductivity of nanolaminates L. H. Liang

  5. SHORT CIRCUITS IN THERMALLY IONIZED PLASMAS: A MECHANISM FOR INTERMITTENT HEATING OF PROTOPLANETARY DISKS

    SciTech Connect (OSTI)

    Hubbard, Alexander; McNally, Colin P.; Mac Low, Mordecai-Mark, E-mail: ahubbard@amnh.org, E-mail: cmcnally@nbi.dk, E-mail: mordecai@amnh.org [Department of Astrophysics, American Museum of Natural History, 79th St. at Central Park West, New York, NY 10024-5192 (United States)

    2012-12-10T23:59:59.000Z

    Many astrophysical systems of interest, including protoplanetary accretion disks, are made of turbulent magnetized gas with near-solar metallicity. Thermal ionization of alkali metals in such gas exceeds non-thermal ionization when temperatures climb above roughly 1000 K. As a result, the conductivity, proportional to the ionization fraction, gains a strong, positive dependence on temperature. In this paper, we demonstrate that this relation between the temperature and the conductivity triggers an exponential instability that acts similarly to an electrical short, where the increased conductivity concentrates the current and locally increases the Ohmic heating. This contrasts with the resistivity increase expected in an ideal magnetic reconnection region. The instability acts to focus narrow current sheets into even narrower sheets with far higher currents and temperatures. We lay out the basic principles of this behavior in this paper using protoplanetary disks as our example host system, motivated by observations of chondritic meteorites and their ancestors, dust grains in protoplanetary disks, that reveal the existence of strong, frequent heating events that this instability could explain.

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

    SciTech Connect (OSTI)

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

    2011-02-01T23:59:59.000Z

    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.

  7. About influence of gravity on heat conductivity process of the Planets

    E-Print Network [OSTI]

    S. O. Gladkov; Anil Yadav; Saibal Ray; F. Rahaman

    2014-07-30T23:59:59.000Z

    In the present study it is shown that the interaction of a quasi-static gravitational wave through density fluctuations gives rise to a heat conductivity coefficient and hence temperature. This fact is a very important characteristics to establish a heat equilibrium process of such massive body as the Earth and other Planets. To carry out this exercise general mechanism has been provided, which makes a bridge between classical physics and quantum theory, and specific dependence of heat conductivity coefficient in wide region is also calculated.

  8. About influence of gravity on heat conductivity process of the Planets

    E-Print Network [OSTI]

    Gladkov, S O; Ray, Saibal; Rahaman, F

    2015-01-01T23:59:59.000Z

    In the present study it is shown that the interaction of a quasi-static gravitational wave through density fluctuations gives rise to a heat conductivity coefficient and hence temperature. This fact is a very important characteristics to establish a heat equilibrium process of such massive body as the Earth and other Planets. To carry out this exercise general mechanism has been provided, which makes a bridge between classical physics and quantum theory, and specific dependence of heat conductivity coefficient in wide region is also calculated.

  9. Fourier Heat Conduction as a phenomenon described within the scope of the Second Law

    E-Print Network [OSTI]

    Christopher G. Jesudason

    2014-07-29T23:59:59.000Z

    The historical development of the Carnot cycle necessitated the construction of isothermal and adiabatic pathways within the cycle that were also mechanically "reversible" which lead eventually to the Kelvin-Clausius development of the entropy function where the heat absorption is for the diathermal (isothermal) paths of the cycle only. It is deduced from traditional arguments that Fourier heat conduction involves mechanically "reversible" heat transfer with irreversible entropy increase. Here we model heat conduction as a thermodynamically reversible but mechanically irreversible process. The MD simulations conducted shows excellent agreement with the theory. Such views and results as these, if developed to a successful conclusion could imply that the Carnot cycle be viewed as describing a local process of energy-work conversion and that irreversible local processes might be brought within the scope of this cycle, implying a unified treatment of thermodynamically (i) irreversible, (ii) reversible, (iii) isothermal and (iv) adiabatic processes.

  10. On Energy and Entropy Influxes in the Green-Naghdi Type III Theory of Heat Conduction

    E-Print Network [OSTI]

    Swantje Bargmann; Antonino Favata; Paolo Podio-Guidugli

    2012-09-13T23:59:59.000Z

    The energy-influx/entropy-influx relation in the Green-Naghdi Type III theory of heat conduction is examined within a thermodynamical framework \\`a la Mueller-Liu, where that relation is not specified a priori irrespectively of the constitutive class under attention. It is shown that the classical assumption, i.e., that the entropy influx and the energy influx are proportional via the absolute temperature, holds true if heat conduction is, in a sense that is made precise, isotropic. In addition, it is proven that the standard assumption does not hold in case of transversely isotropic conduction.

  11. Analysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp characteristics

    E-Print Network [OSTI]

    Klotzkin, David

    injection which we term "thermal impact" , the ther- mal conductivity of the active region is estimatedAnalysis of the reduced thermal conductivity in InGaAs/GaAs quantum dot lasers from chirp; published online 21 September 2006 The thermal conductivity of self-organized quantum dot QD active regions

  12. PHYSICAL REVIEW B 90, 174107 (2014) High-throughput computational screening of thermal conductivity, Debye temperature, and

    E-Print Network [OSTI]

    Curtarolo, Stefano

    for the past few decades [6]. Low thermal conductivity materials constitute the basis of a new generation such as the Debye temperature and the thermal conductivity of materials. We demonstrate that the AGL method, which ranking of the thermal conductivity for several different classes of semiconductor materials

  13. Thermal Conduction in Suspended Graphene Layers A. A.BALANDIN, S. GHOSH, D. L. NIKA AND E. P. POKATILOV

    E-Print Network [OSTI]

    ' properties. Materials with very high or very low thermal conductivities attract particular attention due and engineering research communities to the thermal conductivity of materials. This is explained by both in its atomic structure and the knowledge of thermal conductivity can shed light on many other materials

  14. Suppression of thermal conductivity in InxGa12xN alloys by nanometer-scale disorder

    E-Print Network [OSTI]

    Wu, Junqiao

    power requires low lattice thermal conductivity while maintaining high mobility of the charge carriers. The binary InN and GaN materials have high ther- mal conductivity materials9­14 (the room-temperature thermalSuppression of thermal conductivity in InxGa12xN alloys by nanometer-scale disorder T. Tong,1,a) D

  15. Thermal conductance of solid-liquid interfaces Scott Huxtable, Zhenbin Ge, David G. Cahill

    E-Print Network [OSTI]

    Braun, Paul

    thermal conductivity in nanostructured materials ­ improved thermoelectric energy conversion improved/surfactant/water PMMA/Al2O3 nanotube/alkane #12;Modulated pump-probe apparatus f=10 MHz rf lock-in #12;Solid · Cooling rate (RC time constant) gives interface conductance G = 12 MW m-2 K-1G = 12 MW m K #12;Application

  16. Plate Fin Heat Exchanger Model with Axial Conduction and Variable Properties

    SciTech Connect (OSTI)

    Hansen, B.J.; White, M.J.; Klebaner, A.; /Fermilab

    2011-06-10T23:59:59.000Z

    Future superconducting radio frequency (SRF) cavities, as part of Project X at Fermilab, will be cooled to superfluid helium temperatures by a cryogenic distribution system supplying cold supercritical helium. To reduce vapor fraction during the final Joule-Thomson (J-T) expansion into the superfluid helium cooling bath, counter-flow, plate-fin heat exchangers will be utilized. Due to their compact size and ease of fabrication, plate-fin heat exchangers are an effective option. However, the design of compact and high-effectiveness cryogenic heat exchangers operating at liquid helium temperatures requires consideration of axial heat conduction along the direction of flow, in addition to variable fluid properties. Here we present a numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger. The model is used to guide design decisions on heat exchanger material choice and geometry. In addition, the J-T expansion process is modeled with the heat exchanger to analyze the effect of heat load and cryogenic supply parameters. A numerical model that includes the effects of axial conduction and variable properties for a plate fin heat exchanger was developed and the effect of various design parameters on overall heat exchanger size was investigated. It was found that highly conductive metals should be avoided in the design of compact JT heat exchangers. For the geometry considered, the optimal conductivity is around 3.5 W/m-K and can range from 0.3-10 W/m-K without a large loss in performance. The model was implemented with an isenthalpic expansion process. Increasing the cold side inlet temperature from 2K to 2.2 K decreased the liquid fraction from 0.856 to 0.839 which corresponds to a 0.12 g/s increase in supercritical helium supply needed to maintain liquid level in the cooling bath. Lastly, it was found that the effectiveness increased when the heat load was below the design value. Therefore, the heat exchanger should be sized on the high end of the required heat load.

  17. Conductivity heating a subterranean oil shale to create permeability and subsequently produce oil

    SciTech Connect (OSTI)

    Van Meurs, P.; DeRouffignac, E.P.; Vinegar, H.J.; Lucid, M.F.

    1989-12-12T23:59:59.000Z

    This patent describes an improvement in a process in which oil is produced from a subterranean oil shale deposit by extending at least one each of heat-injecting and fluid-producing wells into the deposit, establishing a heat-conductive fluid-impermeable barrier between the interior of each heat-injecting well and the adjacent deposit, and then heating the interior of each heat-injecting well at a temperature sufficient to conductively heat oil shale kerogen and cause pyrolysis products to form fractures within the oil shale deposit through which the pyrolysis products are displaced into at least one production well. The improvement is for enhancing the uniformity of the heat fronts moving through the oil shale deposit. Also described is a process for exploiting a target oil shale interval, by progressively expanding a heated treatment zone band from about a geometric center of the target oil shale interval outward, such that the formation or extension of vertical fractures from the heated treatment zone band to the periphery of the target oil shale interval is minimized.

  18. SENSIBLE HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT

    E-Print Network [OSTI]

    Baldwin, Thomas F.

    2011-01-01T23:59:59.000Z

    ADVANCED THERMAL ENERGY STORAGE CONCEPT DEFINITION STUDY FORSchilling. F. E. , Thermal Energy Storage Using PrestressedNo ~cumulate thermal energy storage. Estimate ESTrof2(

  19. Transient-heat-transfer and stress analysis of a thermal-storage solar cooker module

    E-Print Network [OSTI]

    Zengeni, Hazel C

    2014-01-01T23:59:59.000Z

    This paper details the analysis carried out in Solidworks to determine the best material and configuration of a thermal-storage solar cooker module.The thermal-storage solar cooker utilizes the high-latent-heat lithium ...

  20. Nanoscale size dependence parameters on lattice thermal conductivity of Wurtzite GaN nanowires

    SciTech Connect (OSTI)

    Mamand, S.M., E-mail: soran.mamand@univsul.net [Department of Physics, College of Science, University of Sulaimani, Sulaimanyah, Iraqi Kurdistan (Iraq); Omar, M.S. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)] [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Muhammad, A.J. [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)] [Department of Physics, College of Science, University of Kirkuk, Kirkuk (Iraq)

    2012-05-15T23:59:59.000Z

    Graphical abstract: Temperature dependence of calculated lattice thermal conductivity of Wurtzite GaN nanowires. Highlights: Black-Right-Pointing-Pointer A modified Callaway model is used to calculate lattice thermal conductivity of Wurtzite GaN nanowires. Black-Right-Pointing-Pointer A direct method is used to calculate phonon group velocity for these nanowires. Black-Right-Pointing-Pointer 3-Gruneisen parameter, surface roughness, and dislocations are successfully investigated. Black-Right-Pointing-Pointer Dislocation densities are decreases with the decrease of wires diameter. -- Abstract: A detailed calculation of lattice thermal conductivity of freestanding Wurtzite GaN nanowires with diameter ranging from 97 to 160 nm in the temperature range 2-300 K, was performed using a modified Callaway model. Both longitudinal and transverse modes are taken into account explicitly in the model. A method is used to calculate the Debye and phonon group velocities for different nanowire diameters from their related melting points. Effect of Gruneisen parameter, surface roughness, and dislocations as structure dependent parameters are successfully used to correlate the calculated values of lattice thermal conductivity to that of the experimentally measured curves. It was observed that Gruneisen parameter will decrease with decreasing nanowire diameters. Scattering of phonons is assumed to be by nanowire boundaries, imperfections, dislocations, electrons, and other phonons via both normal and Umklapp processes. Phonon confinement and size effects as well as the role of dislocation in limiting thermal conductivity are investigated. At high temperatures and for dislocation densities greater than 10{sup 14} m{sup -2} the lattice thermal conductivity would be limited by dislocation density, but for dislocation densities less than 10{sup 14} m{sup -2}, lattice thermal conductivity would be independent of that.

  1. Numerical Investigation of Stratified Thermal Storage Tank Applied in Adsorption Heat Pump Cycle.

    E-Print Network [OSTI]

    Taheri, Hadi

    2014-01-01T23:59:59.000Z

    ??With the aid of the TES (Thermal Energy Storage) in the adsorption heat pump cycle, the COP of the system can be improved. Different geometrical… (more)

  2. Emergence and control of heat current from strict zero thermal bias Jie Ren* and Baowen Li

    E-Print Network [OSTI]

    Li, Baowen

    energy transport. An open question is whether we can create and control heat current at strict zero future. Heat transfers spontaneously from a high temperature to a low one; thus, the control of heatEmergence and control of heat current from strict zero thermal bias Jie Ren* and Baowen Li NUS

  3. FAST STATIC AND DYNAMIC GRID LEVEL THERMAL SIMULATION CONSIDERING TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY OF SILICON

    E-Print Network [OSTI]

    Ziabari, Amirkoushyar

    2012-01-01T23:59:59.000Z

    is based on an equivalent circuit of thermal resistances andof convection resistance to 0.13 K/W. This is equivalent toequivalent convection coefficient. h = 1/(R × A) The convection resistance

  4. Modeling the heating of the Green Energy Lab in Shanghai by the geothermal heat pump combined with the solar thermal energy and ground energy storage.

    E-Print Network [OSTI]

    Yu, Candice Yau May

    2012-01-01T23:59:59.000Z

    ?? This work involves the study of heating systems that combine solar collectors, geothermal heat pumps and thermal energy storage in the ground. Solar collectors… (more)

  5. An optimal guarding scheme for thermal conductivity measurement using a guarded cut-bar technique, part 1 experimental study

    SciTech Connect (OSTI)

    Changhu Xing [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Colby Jensen [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Charles Folsom [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Heng Ban [Utah State Univ., Logan, UT (United States). Dept. of Mechanical and Aerospace Engineering; Douglas W. Marshall [Idaho National Laboratory (INL), Idaho Falls, ID (United States)

    2014-01-01T23:59:59.000Z

    In the guarded cut-bar technique, a guard surrounding the measured sample and reference (meter) bars is temperature controlled to carefully regulate heat losses from the sample and reference bars. Guarding is typically carried out by matching the temperature profiles between the guard and the test stack of sample and meter bars. Problems arise in matching the profiles, especially when the thermal conductivitiesof the meter bars and of the sample differ, as is usually the case. In a previous numerical study, the applied guarding condition (guard temperature profile) was found to be an important factor in measurement accuracy. Different from the linear-matched or isothermal schemes recommended in literature, the optimal guarding condition is dependent on the system geometry and thermal conductivity ratio of sample to meter bar. To validate the numerical results, an experimental study was performed to investigate the resulting error under different guarding conditions using stainless steel 304 as both the sample and meter bars. The optimal guarding condition was further verified on a certified reference material, pyroceram 9606, and 99.95% pure iron whose thermal conductivities are much smaller and much larger, respectively, than that of the stainless steel meter bars. Additionally, measurements are performed using three different inert gases to show the effect of the insulation effective thermal conductivity on measurement error, revealing low conductivity, argon gas, gives the lowest error sensitivity when deviating from the optimal condition. The result of this study provides a general guideline for the specific measurement method and for methods requiring optimal guarding or insulation.

  6. Role of anisotropic thermal conductivity in the reversed-field pinch dynamics

    SciTech Connect (OSTI)

    Onofri, M.; Malara, F.; Veltri, P. [Dipartimento di Fisica, Universita della Calabria, ponte P. Bucci, Cubo 31C, 87036 Rende (Italy)

    2011-05-15T23:59:59.000Z

    Two compressible magnetohydrodynamics simulations of the reversed-field pinch are performed, with isotropic and anisotropic thermal conductivity. We describe in detail the numerical method we use to reproduce the effect of a large parallel thermal conductivity, which makes magnetic field lines almost isothermal. We compare the results of the two simulations, showing that the anisotropic thermal conductivity causes the formation of a hot island when closed magnetic surfaces exist, while temperature becomes almost uniform when the magnetic field is chaotic. After a transient single-helicity state that is formed in the initial phase, a stationary state is reached where the RFP configuration exists in a multiple helicity state, even though the Hartmann number is below the threshold found in previous simulations for the formation of multiple helicity states.

  7. Thermal Conductivity of Thermally-Isolating Polymeric and Composite Structural Support Materials Between 0.3 and 4 K

    E-Print Network [OSTI]

    M. C. Runyan; W. C. Jones

    2008-06-11T23:59:59.000Z

    We present measurements of the low-temperature thermal conductivity of a number of polymeric and composite materials from 0.3 to 4 K. The materials measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301, G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and graphite rod. These materials have moderate to high elastic moduli making them useful for thermally-isolating structural supports.

  8. Thermal Conductivity of Thermally-Isolating Polymeric and Composite Structural Support Materials Between 0.3 and 4 K

    E-Print Network [OSTI]

    Runyan, M C

    2008-01-01T23:59:59.000Z

    We present measurements of the low-temperature thermal conductivity of a number of polymeric and composite materials from 0.3 to 4 K. The materials measured are Vespel SP-1, Vespel SP-22, unfilled PEEK, 30% carbon fiber-filled PEEK, 30% glass-filled PEEK, carbon fiber Graphlite composite rod, Torlon 4301, G-10/FR-4 fiberglass, pultruded fiberglass composite, Macor ceramic, and graphite rod. These materials have moderate to high elastic moduli making them useful for thermally-isolating structural supports.

  9. Pump-probe measurements of the thermal conductivity tensor for materials lacking in-plane symmetry

    SciTech Connect (OSTI)

    Feser, Joseph P. [Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Liu, Jun; Cahill, David G. [Department of Materials Science and Engineering, and Frederick-Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801 (United States)

    2014-10-15T23:59:59.000Z

    We previously demonstrated an extension of time-domain thermoreflectance (TDTR) which utilizes offset pump and probe laser locations to measure in-plane thermal transport properties of multilayers. However, the technique was limited to systems of transversely isotropic materials studied using axisymmetric laser intensities. Here, we extend the mathematics so that data reduction can be performed on non-transversely isotropic systems. An analytic solution of the diffusion equation for an N-layer system is given, where each layer has a homogenous but otherwise arbitrary thermal conductivity tensor and the illuminating spots have arbitrary intensity profiles. As a demonstration, we use both TDTR and time-resolved magneto-optic Kerr effect measurements to obtain thermal conductivity tensor elements of <110> ?-SiO{sub 2}. We show that the out-of-phase beam offset sweep has full-width half-maxima that contains nearly independent sensitivity to the in-plane thermal conductivity corresponding to the scanning direction. Also, we demonstrate a Nb-V alloy as a low thermal conductivity TDTR transducer layer that helps improve the accuracy of in-plane measurements.

  10. A robust and well shielded thermal conductivity device for low temperature measurements

    SciTech Connect (OSTI)

    Toews, W. H.; Hill, R. W. [GWPI and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)] [GWPI and Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

    2014-04-15T23:59:59.000Z

    We present a compact mechanically robust thermal conductivity measurement apparatus for measurements at low temperatures (<1 K) and high magnetic fields on small high-purity single crystal samples. A high-conductivity copper box is used to enclose the sample and all the components. The box provides protection for the thermometers, heater, and most importantly the sample increasing the portability of the mount. In addition to physical protection, the copper box is also effective at shielding radio frequency electromagnetic interference and thermal radiation, which is essential for low temperature measurements. A printed circuit board in conjunction with a braided ribbon cable is used to organize the delicate wiring and provide mechanical robustness.

  11. Normal Heat Conductivity in a strongly pinned chain of anharmonic oscillators

    E-Print Network [OSTI]

    R. Lefevere; A. Schenkel

    2005-11-03T23:59:59.000Z

    We consider a chain of coupled and strongly pinned anharmonic oscillators subject to a non-equilibrium random forcing. Assuming that the stationary state is approximately Gaussian, we first derive a stationary Boltzmann equation. By localizing the involved resonances, we next invert the linearized collision operator and compute the heat conductivity. In particular, we show that the Gaussian approximation yields a finite conductivity $\\kappa\\sim\\frac{1}{\\lambda^2T^2}$, for $\\lambda$ the anharmonic coupling strength.

  12. A Novel Integrated Frozen Soil Thermal Energy Storage and Ground-Source Heat Pump System

    E-Print Network [OSTI]

    Jiang, Y.; Yao, Y.; Rong, L.; Ma, Z.

    2006-01-01T23:59:59.000Z

    In this paper, a novel integrated frozen soil thermal energy storage and ground-source heat pump (IFSTS&GSHP) system in which the GHE can act as both cold thermal energy storage device and heat exchanger for GSHP is first presented. The IFSTS...

  13. INNOVATIVE DESIGN AND MATERIAL SOLUTIONS OF THERMAL CONTACT LAYERS FOR HIGH HEAT FLUX APPLICATIONS IN FUSION

    E-Print Network [OSTI]

    Tillack, Mark

    INNOVATIVE DESIGN AND MATERIAL SOLUTIONS OF THERMAL CONTACT LAYERS FOR HIGH HEAT FLUX APPLICATIONS of sacrificial plasma facing components that have to handle the high heat and particle fluxes in ITER armour thermal and electrical contact with the cooled sub-structure while promoting remote, in

  14. The role of radiation transport in the thermal response of semitransparent materials to localized laser heating

    SciTech Connect (OSTI)

    Colvin, Jeffrey; Shestakov, Aleksei; Stoelken, James; Vignes, Ryan [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551 (United States)

    2011-03-01T23:59:59.000Z

    Lasers are widely used to modify the internal structure of semitransparent materials for a wide variety of applications, including waveguide fabrication and laser glass damage healing. The gray diffusion approximation used in past models to describe radiation cooling is not adequate for these materials, particularly near the heated surface layer. In this paper we describe a computational model based upon solving the radiation transport equation in 1D by the P{sub n} method with {approx}500 photon energy bands, and by multi-group radiation diffusion in 2D with fourteen photon energy bands. The model accounts for the temperature-dependent absorption of infrared laser light and subsequent redistribution of the deposited heat by both radiation and conductive transport. We present representative results for fused silica irradiated with 2-12 W of 4.6 or 10.6 {mu}m laser light for 5-10 s pulse durations in a 1 mm spot, which is small compared to the diameter and thickness of the silica slab. We show that, unlike the case for bulk heating, in localized infrared laser heating radiation transport plays only a very small role in the thermal response of silica.

  15. Effective thermal conductivity of two-phase functionally graded particulate H. M. Yin, G. H. Paulino,a

    E-Print Network [OSTI]

    Paulino, Glaucio H.

    , a continuous trade-off of fracture toughness and high thermal conductivity of metals is made with ceramic of the ceramic portions of FGMs. The effective thermal properties in the gradation direction are es- sentialEffective thermal conductivity of two-phase functionally graded particulate composites H. M. Yin, G

  16. Testing the physics of heat conduction using high pressure: crystals, glasses, and interfaces

    E-Print Network [OSTI]

    Braun, Paul

    of Illinois at Urbana Champaign Bin Chen California Institute of Technology Jackie Li University of Michigan G. Cahill, Wen-Pin Hsieh, Mark Losego, Austin Lyons, Paul Braun, Dallas Trinkle, Eric Pop University-mismatch model for interfaces PMMA polymer water ice VII Al/graphene/Si #12;Thermal conductivity and interface

  17. Heat conduction problem of an evaporating liquid T. Barta, V. Janecek, D. Prazak

    E-Print Network [OSTI]

    Bárta, Tomás

    ratio = kL/kS (e.g. for water on metallic heater 10-3 ) for which the perturbation of temperature of authors, see e.g. [13, 11, 3, 6]. Majority of research publications rely on isothermal heater pressure) of the solid heater. Such assumption is justified for vanishing liquid-solid thermal conductivity

  18. SENSIBLE HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT

    E-Print Network [OSTI]

    Baldwin, Thomas F.

    2011-01-01T23:59:59.000Z

    process configurations for solar power plants with sensible-heatsolar power plant with sensible-heat storage since the chemical~heat storage processsolar power plant with a sulfur-oxide storage process. chemical~heat

  19. Energy-Conservation Clustering Protocol based on Heat Conductivity for Wireless Sensor Networks

    E-Print Network [OSTI]

    Landfeldt, Bjorn

    -sensors based on MEMS (Micro-Electro-Mechanical Systems) technology. A wireless sensor network is composedEnergy-Conservation Clustering Protocol based on Heat Conductivity for Wireless Sensor Networks critical issues in wireless sensor networks is energy efficiency because of the limited energy network

  20. Heat Flow Determinations and Implied Thermal Regime of the Coso...

    Open Energy Info (EERE)

    group, greater than 6.5 HFU, are characteristic of regions with considerable convective heat transfer in the shallow subsurface. The high heat flow values are essentially...

  1. Heat flow determinations and implied thermal regime of the Coso...

    Open Energy Info (EERE)

    group, greater than 6.5 HFU, are characteristic of regions with considerable convective heat transfer in the shallow subsurface. The high heat flow values are essentially...

  2. The thermally stimulated conductivity in amorphous thin film As?Se?

    E-Print Network [OSTI]

    Bryant, John Duffie

    1972-01-01T23:59:59.000Z

    Voltage (Temperature vs. Time) 21 Block Diagrams of the Temperature Control Systems 23 II-8 Parabolic Reference Voltage (Voltage vs. Time) II-9 System Heating Curves Using the Heater Control System (Temper'ature vs. Time) 25 II-10 Block Diagram.... 10 /Temperature) 32 III-3 Conductivity as Function of Temperature for the TSC Experiment (Conductivity vs. Temperature) I II 4 Carrier Concentration as Function of Temperature for TSC (Carrier Concentration vs. Temperature) 35 LIST OF SYNBOLS...

  3. Hyper-resistivity and electron thermal conductivity due to destroyed magnetic surfaces in axisymmetric plasma equilibria

    SciTech Connect (OSTI)

    Weening, R. H. [Department of Radiologic Sciences, Thomas Jefferson University, 901 Walnut Street, Philadelphia, Pennsylvania 19107-5233 (United States)

    2012-06-15T23:59:59.000Z

    In order to model the effects of small-scale current-driven magnetic fluctuations in a mean-field theoretical description of a large-scale plasma magnetic field B(x,t), a space and time dependent hyper-resistivity {Lambda}(x,t) can be incorporated into the Ohm's law for the parallel electric field E Dot-Operator B. Using Boozer coordinates, a theoretical method is presented that allows for a determination of the hyper-resistivity {Lambda}({psi}) functional dependence on the toroidal magnetic flux {psi} for arbitrary experimental steady-state Grad-Shafranov axisymmetric plasma equilibria, if values are given for the parallel plasma resistivity {eta}({psi}) and the local distribution of any auxiliary plasma current. Heat transport in regions of plasma magnetic surfaces destroyed by resistive tearing modes can then be modeled by an electron thermal conductivity k{sub e}({psi})=({epsilon}{sub 0}{sup 2}m{sub e}/e{sup 2}){Lambda}({psi}), where e and m{sub e} are the electron charge and mass, respectively, while {epsilon}{sub 0} is the permittivity of free space. An important result obtained for axisymmetric plasma equilibria is that the {psi}{psi}-component of the metric tensor of Boozer coordinates is given by the relation g{sup {psi}{psi}}({psi}){identical_to}{nabla}{psi} Dot-Operator {nabla}{psi}=[{mu}{sub 0}G({psi})][{mu}{sub 0}I({psi})]/{iota}({psi}), with {mu}{sub 0} the permeability of free space, G({psi}) the poloidal current outside a magnetic surface, I({psi}) the toroidal current inside a magnetic surface, and {iota}({psi}) the rotational transform.

  4. On the solution of the Heaviside - Klein - Gordon thermal equation for heat transport in graphene

    E-Print Network [OSTI]

    Magdalena Pelc

    2007-11-26T23:59:59.000Z

    We report studies of the solution of the Heaviside - Klein - Gordon thermal equation. As the result it is shown that the solution consists of two components: the fast thermal wave and slow diffusion for very large (compared to relaxation time) time period. We argue that the fast thermal wave can be recognized as the indication of the ballistic heat transport. As an example we consider the ballistic heat transport in graphene.

  5. Vacuum Induction Melting Unit Induction heating is a process wherein induced eddy currents heat conductive materials. This heating

    E-Print Network [OSTI]

    Subramaniam, Anandh

    graphite) crucible inside the coil. The coil serves as the transformer primary and the part to be heated Principle: An outline of the induction melting system is presented here. A solid state RF power supply sends can be melted at a time. There are three main parts to the system: chiller, power unit and vacuum unit

  6. Controlling the thermal contact resistance of a carbon nanotube heat spreader

    E-Print Network [OSTI]

    Li, Teng

    Controlling the thermal contact resistance of a carbon nanotube heat spreader Kamal H. Baloch,1 electron thermal microscopy shows that the thermal contact resistance of a nanotube weakly coupled to its Norvik Voskanian,2 and John Cumings2,a 1 Department of Materials Science and Engineering, Institute

  7. PHYSICAL REVIEW B 83, 094521 (2011) Thermal conductivity in the mixed state of a superconductor at low magnetic fields

    E-Print Network [OSTI]

    Alexei, Koshelev

    15 March 2011) We evaluate accurate low-field/low-temperature asymptotics of the thermal conductivityPHYSICAL REVIEW B 83, 094521 (2011) Thermal conductivity in the mixed state of a superconductor conductivity at low fields. DOI: 10.1103/PhysRevB.83.094521 PACS number(s): 74.25.fc, 74.25.Uv I. INTRODUCTION

  8. Economical Analysis of a Groundwater Source Heat Pump with Water Thermal Storage System

    E-Print Network [OSTI]

    Zhou, Z.; Xu, W.; Li, J.; Zhao, J.; Niu, L.

    2006-01-01T23:59:59.000Z

    The paper is based on a chilled and heat source for the building which has a total area of 140000m2 in the suburb of Beijing. By comparing the groundwater source heat pump of water thermal storage (GHPWTS) with a conventional chilled and heat source...

  9. WICKING OPTIMIZATION FOR THERMAL COOLING -WITH A TITANIUM BASED HEAT PIPE SYSTEM

    E-Print Network [OSTI]

    MacDonald, Noel C.

    WICKING OPTIMIZATION FOR THERMAL COOLING -WITH A TITANIUM BASED HEAT PIPE SYSTEM C. Ding1* , P for a proposed flat heat pipe system. This unique bitextured titania structure (BTS) provides a suprerhydrophilic based flat heat pipe is proposed to integrate the BTS wicks and study the concept of this titanium based

  10. Proceedings of HT2007 2007 ASME-JSME Thermal Engineering Summer Heat Transfer Conference

    E-Print Network [OSTI]

    Ghajar, Afshin J.

    Proceedings of HT2007 2007 ASME-JSME Thermal Engineering Summer Heat Transfer Conference July 8-12, 2007, Vancouver, British Columbia, CANADA HT2007-32219 VALIDATION OF A GENERAL HEAT TRANSFER, Stillwater, OK 74078, USA E-mail: ghajar@ceat.okstate.edu ABSTRACT A general heat transfer correlation

  11. Analysis and control of the thermal runaway of ceramic slab under microwave heating

    E-Print Network [OSTI]

    Sheen, Dongwoo

    Analysis and control of the thermal runaway of ceramic slab under microwave heating Changjun Liu of the dielectrics during microwave heating, in which there is a big jump of the steady-state temperature while the applied microwave power varies slightly. It hinders engineers in the applications of microwave heating

  12. Statistical properties of the energy exchanged between two heat baths coupled by thermal fluctuations

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    particles kept at different temperatures and coupled by an elastic force. We measure the heat flowingStatistical properties of the energy exchanged between two heat baths coupled by thermal systems in contact with a single heat bath and driven out of equilibrium by external forces [1, 2, 3, 4, 5

  13. Experimental investigation of size effect on thermal conductivity for ultra-thin amorphous poly(methyl methacrylate) (PMMA) films

    E-Print Network [OSTI]

    Kim, Ick Chan

    2009-05-15T23:59:59.000Z

    An investigation was conducted to determine whether a “size effect” phenomenon for one particular thermophysical property, thermal conductivity, actually exists for amorphous poly(methyl methacrylate) (PMMA) films with thicknesses ranging from 40 nm...

  14. Thermal conductivity of ultra-thin chemical vapor deposited hexagonal boron nitride films

    SciTech Connect (OSTI)

    Alam, M. T.; Haque, M. A., E-mail: mah37@psu.edu [Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Bresnehan, M. S.; Robinson, J. A. [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)] [Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA and The Center for Two-Dimensional and Layered Materials, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-01-06T23:59:59.000Z

    Thermal conductivity of freestanding 10?nm and 20?nm thick chemical vapor deposited hexagonal boron nitride films was measured using both steady state and transient techniques. The measured value for both thicknesses, about 100?±?10?W m{sup ?1} K{sup ?1}, is lower than the bulk basal plane value (390?W m{sup ?1} K{sup ?1}) due to the imperfections in the specimen microstructure. Impressively, this value is still 100 times higher than conventional dielectrics. Considering scalability and ease of integration, hexagonal boron nitride grown over large area is an excellent candidate for thermal management in two dimensional materials-based nanoelectronics.

  15. Thermal Conductivity of SiC/Si Composites – Porting PNNL EMTA Code for Fusion Analyses

    SciTech Connect (OSTI)

    Henager, Charles H.; Nguyen, Ba Nghiep

    2013-04-19T23:59:59.000Z

    An existing modeling method, the EMTA (Eshelby-Mori-Tanaka approach) modeling approach [1], is applied to the study of SiC/SiC 2D woven composites for fusion reactor applications for the first time, to the best of our knowledge, with excellent results. We compare EMTA model results to existing thermal conductivity data for these materials and suggest that in the future this approach can be beneficial by providing us with tools to further optimize these composite materials for fusion energy applications since the EMTA method and code can address both thermal and mechanical properties with the same framework.

  16. BSU GHP District Heating and Cooling System (Phase I)

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    of Concept" completed * Borehole field designed using "Thermal Dynamics" software * Heat Pump Chiller requirements determined * Surveys conducted throughout campus to...

  17. 5. Heat transfer Ron Zevenhoven

    E-Print Network [OSTI]

    Zevenhoven, Ron

    1/120 5. Heat transfer Ron Zevenhoven �bo Akademi University Thermal and Flow Engineering / Värme Three heat transfer mechanisms Conduction Convection Radiation 2/120 Pic: B�88 �bo Akademi University | Thermal and Flow Engineering | 20500 Turku | Finland #12;3/120 5.1 Conductive heat transfer �bo Akademi

  18. Development of a Test Technique to Determine the Thermal Conductivity of Large Refractory Ceramic Test Specimens

    SciTech Connect (OSTI)

    Hemrick, James Gordon [ORNL; Dinwiddie, Ralph Barton [ORNL; Loveland, Erick R [ORNL; Prigmore, Andre L [ORNL

    2012-01-01T23:59:59.000Z

    A method has been developed to utilize the High Intensity Infrared lamp located at Oak Ridge National Laboratory for the measurement of thermal conductivity of bulk refractory materials at elevated temperatures. The applicability of standardized test methods to determine the thermal conductivity of refractory materials at elevated temperatures is limited to small sample sizes (laser flash) or older test methods (hot wire, guarded hot plate), which have their own inherent problems. A new method, based on the principle of the laser flash method, but capable of evaluating test specimens on the order of 200 x 250 x 50 mm has been developed. Tests have been performed to validate the method and preliminary results are presented in this paper.

  19. Effect of phonon confinement on lattice thermal conductivity of lead Telluride quantum well structure

    SciTech Connect (OSTI)

    Tripathi, Madhvendra Nath, E-mail: ommadhav27@gmail.com [Department of Pure and Applied Physics, Guru Ghasidas Vishwavidyalaya, Bilaspur-495009, Chhattisgarh (India)

    2014-04-24T23:59:59.000Z

    The paper examines the effect of spatial confinement of acoustic phonons on average group velocity and consequently the lattice thermal conductivity of a free-standing PbTe quantum well structure and their temperature dependence. The average group velocity at 100 Å decreases 30% to the bulk value and falls more rapidly on reducing the width of quantum well. Moreover, the lattice thermal conductivity of 100 Å wide PbTe quantum well with value of 0.60 W/mK shows considerable decrease of 70% compared to it’s bulk value. It is observed that the effect of reduction in well width is less pronounce as temperature increases. This appears mainly due to dominance of umklapp processes over the confinement effects.

  20. The Impact of Thermal Conductivity and Diffusion Rates on Water Vapor Transport through Gas Diffusion Layers

    E-Print Network [OSTI]

    Burlatsky, S F; Gummallaa, M; Condita, D; Liua, F

    2013-01-01T23:59:59.000Z

    Water management in a hydrogen polymer electrolyte membrane (PEM) fuel cell is critical for performance. The impact of thermal conductivity and water vapor diffusion coefficients in a gas diffusion layer (GDL) has been studied by a mathematical model. The fraction of product water that is removed in the vapour phase through the GDL as a function of GDL properties and operating conditions has been calculated and discussed. Furthermore, the current model enables identification of conditions when condensation occurs in each GDL component and calculation of temperature gradient across the interface between different layers, providing insight into the overall mechanism of water transport in a given cell design. Water transport mode and condensation conditions in the GDL components depend on the combination of water vapor diffusion coefficients and thermal conductivities of the GDL components. Different types of GDL and water removal scenarios have been identified and related to experimentally-determined GDL proper...

  1. Thermal contact conductance of metallic coated superconductor/copper interfaces at cryogenic temperatures

    E-Print Network [OSTI]

    Ochterbeck, Jay Matthew

    1990-01-01T23:59:59.000Z

    of the vapor deposition process when using soft metallic coatings so that the maximum allowable enhancement for a specific coating thickness can be obtained. Also, the temperature dependence for the microhardness of copper was ex- perimentally determined...- sate for the difFerence in layer and substrate thermal conductivities. When applied, the model agreed well with the data obtained in this investigation at low coating thick- ness but overpredicted the data, as the thickness increased. In addition...

  2. Thermal conductivity studies of novel nanofluids based on metallic silver decorated mesoporous silica nanoparticles

    SciTech Connect (OSTI)

    Tadjarodi, Azadeh, E-mail: tajarodi@iust.ac.ir [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Zabihi, Fatemeh [Research Laboratory of Inorganic Materials Synthesis, Department of Chemistry, Iran University of Science and Technology, 16846-13114 Tehran (Iran, Islamic Republic of); Chemistry and Nanotechnology Laboratory, National Center for Laser Science and Technology, Tehran (Iran, Islamic Republic of)

    2013-10-15T23:59:59.000Z

    Graphical abstract: - Highlights: • Metallic silver was decorated in mSiO{sub 2} with grafted hemiaminal functional groups. • Synthesized nanoparticles were used for preparation of glycerol based nanofluids. • The effect of temperature, weight fraction of mSiO{sub 2} and concentration of silver nanoparticles on thermal conductivity of nanofluids was investigated. - Abstract: In the present study, the mesoporous structure of silica (mSiO{sub 2}) nanoparticles as well as hemiaminal grafted mSiO{sub 2} decorated by metallic silver (Ag/mSiO{sub 2}) has been used for the preparation of glycerol based nanofluids. Structural and morphological characterization of the synthesized products have been carried out using Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD), UV–vis spectroscopy, inductively coupled plasma (ICP) and N{sub 2} adsorption–desorption isotherms. The thermal conductivity and viscosity of the nanofluids have been measured as a function of temperature for various weight fractions and silver concentrations of mSiO{sub 2} and Ag/mSiO{sub 2} nanoparticles, respectively. The results show that the thermal conductivity of the nanofluids increase up to 9.24% as the weight fraction of mSiO{sub 2} increases up to 4 wt%. Also, increasing the percent of the silver decorated mSiO{sub 2} (Ag/mSiO{sub 2}) up to 2.98% caused an enhancement in the thermal conductivity of the base fluid up to 10.95%. Furthermore, the results show that the nanofluids have Newtonian behavior in the tested temperature range for various concentrations of nanoparticles.

  3. Energy Efficient Process Heating: Insulation and Thermal Mass Kevin Carpenter and Kelly Kissock

    E-Print Network [OSTI]

    Kissock, Kelly

    1 Energy Efficient Process Heating: Insulation and Thermal Mass Kevin Carpenter and Kelly Kissock-0210 Phone: (937) 229-2852 Fax: (937) 229-4766 Email: Kelly.Kissock@notes.udayton.edu ABSTRACT Open tanks

  4. Thermal conductance between an SWNT and Lennard-Jones fluid Yasuhiro Igarashi, Junichiro Shiomi and Shigeo Maruyama

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Thermal conductance between an SWNT and Lennard-Jones fluid Yasuhiro Igarashi, Junichiro Shiomi and Shigeo Maruyama Department of Mechanical Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan Thermal conductance between an SWNT and Lennard-Jones fluid is studied

  5. THE JOURNAL OF CHEMICAL PHYSICS 140, 114502 (2014) Thermal conductivity of simple liquids: Origin of temperature and packing

    E-Print Network [OSTI]

    Boyer, Edmond

    . For example, in concen- trating solar power plants1 or in prospective Generation IV nuclear reactors,2THE JOURNAL OF CHEMICAL PHYSICS 140, 114502 (2014) Thermal conductivity of simple liquids: Origin dependence of T1/4 3/2 in the thermal conductivity of the simple Lennard-Jones (LJ) liquid is explored

  6. Accepted by the Journal of Building Physics (2007) Microstructure and Thermal Conductivity of Hydrated Calcium Silicate Board Materials

    E-Print Network [OSTI]

    Bentz, Dale P.

    of Hydrated Calcium Silicate Board Materials Chi T. Do, Dale P. Bentz1 , and Paul E. Stutzman Building and pore size are examined for two calcium silicate boards of different densities. Thermal conductivities; radiation; thermal conductivity. Introduction In recent years, a variety of low-density calcium silicate

  7. Oxidation of Metals, Vol. 61, Nos. 3/4, April 2004 ( 2004) Thermal Conductivity, Phase Stability, and Oxidation

    E-Print Network [OSTI]

    Trice, Rodney W.

    , and Oxidation Resistance of Y3Al5O12 (YAG)/Y2O3­ZrO2 (YSZ) Thermal-Barrier Coatings Y. J. Su, R. W. Trice,# K oxidation resistance while maintaining low thermal conductivity and good phase stability. Padture) is proposed. The objective of this work is to quantify the effect of YAG on thermal resistance, long

  8. Phonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu, and Alexander A. Balandina

    E-Print Network [OSTI]

    or polycrystalline materials in terms of thermal transport. © 2005 American Institute of Physics. DOI: 10 strongly depends on interface conditions, is considered as a major thermal resistive mecha- nismPhonon-hopping thermal conduction in quantum dot superlattices Manu Shamsa, Weili Liu

  9. Heat exchanger device and method for heat removal or transfer

    DOE Patents [OSTI]

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-24T23:59:59.000Z

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  10. Heat exchanger device and method for heat removal or transfer

    DOE Patents [OSTI]

    Koplow, Jeffrey P

    2013-12-10T23:59:59.000Z

    Systems and methods for a forced-convection heat exchanger are provided. In one embodiment, heat is transferred to or from a thermal load in thermal contact with a heat conducting structure, across a narrow air gap, to a rotating heat transfer structure immersed in a surrounding medium such as air.

  11. Heat extraction for the CSPonD thermal storage unit

    E-Print Network [OSTI]

    Rojas, Folkers Eduardo

    2011-01-01T23:59:59.000Z

    Three coiled tube heat exchanger prototypes were designed to extract heat from containers holding 0.5 kg, 2.3 kg, and 10.5 kg of Sodium Nitrate-Potassium Nitrate salt. All of the prototypes were left with an open surface ...

  12. Thermal Solar Energy Systems for Space Heating of Buildings

    E-Print Network [OSTI]

    Gomri, R.; Boulkamh, M.

    2010-01-01T23:59:59.000Z

    to compensate the deficit. In this case a traditional solar heating system having the same characteristics with regard to the solar collecting area and the volume of storage tank is used. It can be concluded that the space heating system using a solar energy...

  13. Waste Heat Recovery System: Lightweight Thermal Energy Recovery (LIGHTER) System

    SciTech Connect (OSTI)

    None

    2010-01-01T23:59:59.000Z

    Broad Funding Opportunity Announcement Project: GM is using shape memory alloys that require as little as a 10°C temperature difference to convert low-grade waste heat into mechanical energy. When a stretched wire made of shape memory alloy is heated, it shrinks back to its pre-stretched length. When the wire cools back down, it becomes more pliable and can revert to its original stretched shape. This expansion and contraction can be used directly as mechanical energy output or used to drive an electric generator. Shape memory alloy heat engines have been around for decades, but the few devices that engineers have built were too complex, required fluid baths, and had insufficient cycle life for practical use. GM is working to create a prototype that is practical for commercial applications and capable of operating with either air- or fluid-based heat sources. GM’s shape memory alloy based heat engine is also designed for use in a variety of non-vehicle applications. For example, it can be used to harvest non-vehicle heat sources, such as domestic and industrial waste heat and natural geothermal heat, and in HVAC systems and generators.

  14. Evidence for thermalization of surface-desorbed molecules at heating rates of 108

    E-Print Network [OSTI]

    Zare, Richard N.

    Evidence for thermalization of surface-desorbed molecules at heating rates of 108 K/s C. R of aniline-d7 from a single-crystal surface 0001 of sapphire Al2O3 at a heating rate on the order of 108 K/s was studied using pulsed infrared laser radiation for desorption and resonance enhanced multiphoton ionization

  15. Heat of the Moment: Characterizing the Efficacy of Thermal Camera-Based Attacks

    E-Print Network [OSTI]

    Heat of the Moment: Characterizing the Efficacy of Thermal Camera-Based Attacks Keaton Mowery UC to analyze the data. First, we present code recovery re- sults from human review of our test data set lock on an industrial safe, he found that body heat from the user transferred to the individual keys

  16. ThermalEngineeringLaboratory,VanderbiltUniversity Convection Heat Transfer of Nanofluids in Commercial

    E-Print Network [OSTI]

    Walker, D. Greg

    EngineeringLaboratory,VanderbiltUniversity Experimental Setup Straight Tube Setup Constant Temperature Bath Parastaltic Pump Nanofluid Reservoir Heated.91 od di Commercial System Setup Heater Insulation Water block 4/10 #12;Thermal gain across the heated tube for the DI-water and the 0.5% nanofluid · Greater temperature gain in the 1

  17. Analytical Study on Thermal and Mechanical Design of Printed Circuit Heat Exchanger

    SciTech Connect (OSTI)

    Su-Jong Yoon; Piyush Sabharwall; Eung-Soo Kim

    2013-09-01T23:59:59.000Z

    The analytical methodologies for the thermal design, mechanical design and cost estimation of printed circuit heat exchanger are presented in this study. In this study, three flow arrangements of parallel flow, countercurrent flow and crossflow are taken into account. For each flow arrangement, the analytical solution of temperature profile of heat exchanger is introduced. The size and cost of printed circuit heat exchangers for advanced small modular reactors, which employ various coolants such as sodium, molten salts, helium, and water, are also presented.

  18. Neutronic and thermal design considerations for heat-pipe reactors

    SciTech Connect (OSTI)

    Ranken, W.A.; Koenig, D.R.

    1983-01-01T23:59:59.000Z

    SABRE (Space-Arena Baseline Reactor) is a 100-kW/sub e/, heat-pipe-cooled, beryllium-reflected, fast reactor that produces heat at a temperature of 1500/sup 0/K and radiatively transmits it to high-temperature thermoelectric (TE) conversion elements. The use of heat pipes for core heat removal eliminates single-point failure mechanisms in the reactor cooling system, and provides minimal temperature drop radiative coupling to the TE array, as well as automatic, self-actuating removal of reactor afterheat. The question of how the failure of a fuel module heat pipe will affect neighboring fuel modules in the core is discussed, as is fission density peaking that occurs at the core/reflector interface. Results of neutronic calculations of the control margin available are described. Another issue that is addressed is that of helium generation in the heat pipes from neutron reactions in the core with the heat pipe fluid. Finally, the growth potential of the SABRE design to much higher powers is examined.

  19. The gravitational heat conduction and the hierarchical structure in solar interior

    E-Print Network [OSTI]

    Zheng Yahui; Du Jiulin

    2014-03-10T23:59:59.000Z

    With the assumption of local Tsallis equilibrium, the newly defined gravitational temperature is calculated in the solar interior, whose distribution curve can be divided into three parts, the solar core region, radiation region and convection region, in excellent agreement with the solar hierarchical structure. By generalizing the Fourier law, one new mechanism of heat conduction, based on the gradient of the gravitational temperature, is introduced into the astrophysical system. This mechanism is related to the self-gravity of such self-gravitating system whose characteristic scale is large enough. It perhaps plays an important role in the astrophysical system which, in the solar interior, leads to the heat accumulation at the bottom of the convection layer and then motivates the convection motion.

  20. Spherical collapse of a heat conducting fluid in higher dimensions without horizon

    E-Print Network [OSTI]

    A. banerjee; S. Chatterjee

    2004-06-08T23:59:59.000Z

    We consider a scenario where the interior spacetime,described by a heat conducting fluid sphere is matched to a Vaidya metric in higher dimensions.Interestingly we get a class of solutions, where following heat radiation the boundary surface collapses without the appearance of an event horizon at any stage and this happens with reasonable properties of matter field.The non-occurrence of a horizon is due to the fact that the rate of mass loss exactly counterbalanced by the fall of boundary radius.Evidently this poses a counter example to the so-called cosmic censorship hypothesis.Two explicit examples of this class of solutions are also given and it is observed that the rate of collapse is delayed with the introduction of extra dimensions.The work extends to higher dimensions our previous investigation in 4D.

  1. HEATING6 analysis of international thermal benchmark problem sets 1 and 2

    SciTech Connect (OSTI)

    Childs, K.W.; Bryan, C.B.

    1986-10-01T23:59:59.000Z

    In order to assess the heat transfer computer codes used in the analysis of nuclear fuel shipping casks, the Nuclear Energy Agency Committee on Reactor Physics has defined seven problems for benchmarking thermal codes. All seven of these problems have been solved using the HEATING6 heat transfer code. This report presents the results of five of the problems. The remaining two problems were used in a previous benchmarking of thermal codes used in the United States, and their solutions have been previously published.

  2. SENSIBLE HEAT STORAGE FOR A SOLAR THERMAL POWER PLANT

    E-Print Network [OSTI]

    Baldwin, Thomas F.

    2011-01-01T23:59:59.000Z

    the exhaust steam in an indirect condenser and rejects heatSteam Feedwater Heaters* - Installed Cost of the Dry-Cooling Tower and Condenser* -steam feedwater heaters Feedwater (50BoK, 14.5 MPa) I nd irect condenser

  3. THERMAL PERFORMANCE MEASUREMENTS ON ULTIMATE HEAT SINKS - COOLING...

    Office of Scientific and Technical Information (OSTI)

    (and-eventually, spray ponds) that are proposed to be used as ultimate heat sinks in nuclear power plant emergency core cooling systems. The need is derived from the concern...

  4. Effects of fiber direction on heat conduction in unidirectionally aligned fiber composites

    E-Print Network [OSTI]

    Havis, Clark Reagan

    1987-01-01T23:59:59.000Z

    Composites, " Journal of Applied Mechanics, Vol. 46, pp. 563-567. 44 APPENDIX A NOMENCI ATURE 2G A A d If k k?k, Iy kf km k?k, k? k?, y, k? kgs~ k~v~ kss i, m) B qs 9cai~ q~s S T W s&p~s /f 'y lF V Vf im r fiber spacing... of MASTER OF SCIENCE December 1987 Major Subject: Mechanical Engineering EFFECTS OF FIBER DIRECTION ON HEAT CONDUCTION IN UNIDIRECTIONALLY ALIGNED FIBER COMPOSITES A Thesis CLARK REAGAN HAVIS Approved as to style and content by: G. P. Peterson...

  5. Prediction of Thermal Conductivity for Irradiated SiC/SiC Composites by Informing Continuum Models with Molecular Dynamics Data

    SciTech Connect (OSTI)

    Nguyen, Ba Nghiep; Gao, Fei; Henager, Charles H.; Kurtz, Richard J.

    2014-05-01T23:59:59.000Z

    This article proposes a new method to estimate the thermal conductivity of SiC/SiC composites subjected to neutron irradiation. The modeling method bridges different scales from the atomic scale to the scale of a 2D SiC/SiC composite. First, it studies the irradiation-induced point defects in perfect crystalline SiC using molecular dynamics (MD) simulations to compute the defect thermal resistance as a function of vacancy concentration and irradiation dose. The concept of defect thermal resistance is explored explicitly in the MD data using vacancy concentrations and thermal conductivity decrements due to phonon scattering. Point defect-induced swelling for chemical vapor deposited (CVD) SiC as a function of irradiation dose is approximated by scaling the corresponding MD results for perfect crystal ?-SiC to experimental data for CVD-SiC at various temperatures. The computed thermal defect resistance, thermal conductivity as a function of grain size, and definition of defect thermal resistance are used to compute the thermal conductivities of CVD-SiC, isothermal chemical vapor infiltrated (ICVI) SiC and nearly-stoichiometric SiC fibers. The computed fiber and ICVI-SiC matrix thermal conductivities are then used as input for an Eshelby-Mori-Tanaka approach to compute the thermal conductivities of 2D SiC/SiC composites subjected to neutron irradiation within the same irradiation doses. Predicted thermal conductivities for an irradiated Tyranno-SA/ICVI-SiC composite are found to be comparable to available experimental data for a similar composite ICVI-processed with these fibers.

  6. System for thermal energy storage, space heating and cooling and power conversion

    DOE Patents [OSTI]

    Gruen, Dieter M. (Downers Grove, IL); Fields, Paul R. (Chicago, IL)

    1981-04-21T23:59:59.000Z

    An integrated system for storing thermal energy, for space heating and cong and for power conversion is described which utilizes the reversible thermal decomposition characteristics of two hydrides having different decomposition pressures at the same temperature for energy storage and space conditioning and the expansion of high-pressure hydrogen for power conversion. The system consists of a plurality of reaction vessels, at least one containing each of the different hydrides, three loops of circulating heat transfer fluid which can be selectively coupled to the vessels for supplying the heat of decomposition from any appropriate source of thermal energy from the outside ambient environment or from the spaces to be cooled and for removing the heat of reaction to the outside ambient environment or to the spaces to be heated, and a hydrogen loop for directing the flow of hydrogen gas between the vessels. When used for power conversion, at least two vessels contain the same hydride and the hydrogen loop contains an expansion engine. The system is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators, but may be used with any source of heat, including a source of low-grade heat.

  7. E-Print Network 3.0 - ac conductivity studies Sample Search Results

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Conductivity, Molecular... Dynamics Simulation, Thermal Conductance ABSTRACT Several heat transfer problems related to single... function between carbon and carbon within a...

  8. Thermal heat radiation, near-field energy density and near-field radiative heat transfer of coated materials

    E-Print Network [OSTI]

    Svend-Age Biehs

    2011-03-15T23:59:59.000Z

    We investigate the thermal radiation and thermal near-field energy density of a metal-coated semi-infinite body for different substrates. We show that the surface polariton coupling within the metal coating leads to an enhancement of the TM-mode part of the thermal near-field energy density when a polar substrate is used. In this case the result obtained for a free standing metal film is retrieved. In contrast, in the case of a metal substrate there is no enhancement in the TM-mode part, as can also be explained within the framework of surface plasmon coupling within the coating. Finally, we discuss the influence of the enhanced thermal energy density on the near-field radiative heat transfer between a simple semi-infinite and a coated semi-infinite body for different material combinations.

  9. Fabrication of high thermal conductivity arrays of carbon nanotubes and their composites

    DOE Patents [OSTI]

    Geohegan, David B. (Knoxville, TN) [Knoxville, TN; Ivanov, Ilya N. (Knoxville, TN) [Knoxville, TN; Puretzky, Alexander A [Knoxville, TN

    2010-07-27T23:59:59.000Z

    Methods and apparatus are described for fabrication of high thermal conductivity arrays of carbon nanotubes and their composites. A composition includes a vertically aligned nanotube array including a plurality of nanotubes characterized by a property across substantially all of the vertically aligned nanotube array. A method includes depositing a vertically aligned nanotube array that includes a plurality of nanotubes; and controlling a deposition rate of the vertically aligned nanotubes array as a function of an in situ monitored property of the plurality of nanotubes.

  10. Thermal analysis of directly buried conduit heat-distribution systems

    SciTech Connect (OSTI)

    Fang, J.B.

    1990-08-01T23:59:59.000Z

    The calculations of heat losses and temperature field for directly buried conduit heat distribution systems were performed using the finite element computer programs. The finite element analysis solved two-dimensional, steady-state heat transfer problems involving two insulated parallel pipes encased in the same conduit casing and in separate casings, and the surrounding earth. Descriptions of the theoretical basis, computational scheme, and the data input and outputs of the developed computer programs are presented. Numerical calculations were carried out for predicting the temperature distributions within the existing high temperature hot water distribution system and two insulated pipes covered in the same metallic conduit and the surrounding soil. The predicted results generally agree with the experimental data obtained at the test site.

  11. MODELING THE TRANSVERSE THERMAL CONDUCTIVITY OF 2D-SICF/SIC COMPOSITES

    SciTech Connect (OSTI)

    Youngblood, Gerald E.; Senor, David J.; Jones, Russell H.

    2002-09-01T23:59:59.000Z

    A hierarchical model was developed to describe the effective transverse thermal conductivity, K effective, of a 2D-SiC/SiC composite made from stacked and infiltrated woven fabric layers in terms of constituent properties and microstructural and architectural variables. The model includes the expected effects of fiber-matrix interfacial conductance as well as the effects of high fiber packing fractions within individual tows and the non-uniform nature of 2D-fabric layers that include a significant amount of interlayer porosity. Model predictions were obtained for two versions of DuPont 2D-Hi Nicalon(Trademark)/PyC/ICVI-SiC composite, one with a thin (0.110 micron) and the other with a thick (1.040 micron) PyC fiber coating. The model predicts that the matrix porosity content and porosity shape factor have a major influence on K effective(T) for such a composite.

  12. On the dynamical Rayleigh-Taylor instability in compressible viscous flows without heat conductivity

    E-Print Network [OSTI]

    Fei Jiang; Song Jiang

    2014-03-20T23:59:59.000Z

    We investigate the instability of a smooth Rayleigh-Taylor steady-state solution to compressible viscous flows without heat conductivity in the presence of a uniform gravitational field in a bounded domain $\\Omega\\subset{\\mathbb R}^3$ with smooth boundary $\\partial\\Omega$. We show that the steady-state is linearly unstable by constructing a suitable energy functional and exploiting arguments of the modified variational method. Then, based on the constructed linearly unstable solutions and a local well-posedness result of classical solutions to the original nonlinear problem, we further reconstruct the initial data of linearly unstable solutions to be the one of the original nonlinear problem and establish an appropriate energy estimate of Gronwall-type. With the help of the established energy estimate, we show that the steady-state is nonlinearly unstable in the sense of Hadamard by a careful bootstrap argument. As a byproduct of our analysis, we find that the compressibility has no stabilizing effect in the linearized problem for compressible viscous flows without heat conductivity.

  13. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    materials (PCM) in solar thermal concentrating technologyeffective and efficient solar thermal electricity generatorbeen considered for solar thermal energy storages. These are

  14. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    Proceedings on thermal energy storage and energy conversion;polymer microcomposites for thermal energy storage. SAE SocLow temperature thermal energy storage: a state of the art

  15. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    E-Print Network [OSTI]

    Gustavsen, Arild

    2009-01-01T23:59:59.000Z

    860. Batchelor, G.K. 1954. Heat transfer by free convectionfree convection. In: Heat Transfer and Turbulent BuoyantHEAT2, A PC-program for heat transfer in two dimensions.

  16. Simulation of Infrared Laser Heating of Silica Using Heat Conduction and Multifrequency Radiation Diffusion Equations Adapted for Homogeneous Refractive Lossy Media

    SciTech Connect (OSTI)

    Shestakov, A I; Matthews, M J; Vignes, R M; Stolken, J S

    2010-10-28T23:59:59.000Z

    Localized, transient heating of materials using micro-scale, highly absorbing laser light has been used in many industries to anneal, melt and ablate material with high precision. Accurate modeling of the relative contributions of conductive, convective and radiative losses as a function of laser parameters is essential to optimizing micro-scale laser processing of materials. In bulk semi-transparent materials such as silicate glass melts, radiation transport is known to play a significantly larger role as the temperature increases. Conventionally, radiation is treated in the frequency-averaged diffusive limit (Rosseland approximation). However, the role and proper treatment of radiative processes under rapidly heated, high thermal gradient conditions, often created through laser-matter interactions, is at present not clear. Starting from the radiation transport equation for homogeneous, refractive lossy media, they derive the corresponding time-dependent multi-frequency diffusion equations. Zeroth and first moments of the transport equation couple the energy density, flux and pressure tensor. The system is closed by neglecting the temporal derivative of the flux and replacing the pressure tensor by its diagonal analogue. The radiation equations are coupled to a diffusion equation for the matter temperature. They are interested in modeling infrared laser heating of silica over sub-millimeter length scales, and at possibly rapid rates. Hence, in contrast to related work, they retain the temporal derivative of the radiation field. They derive boundary conditions at a planar air-silica interface taking account of reflectivities obtained from the Fresnel relations that include absorption. The effect of a temperature-dependent absorption index is explored through construction of a multi-phonon dielectric function that includes mode dispersion. The spectral dimension is discretized into a finite number of intervals yielding a system of multigroup diffusion equations. Simulations are presented. To demonstrate the bulk heat loss due to radiation and the effect of the radiation's temporal derivative, they model cooling of a silica slab, initially at 2500 K, for 10 s. Retaining the derivative enables correctly modeling the loss of photons initially present in the slab. Other simulations model irradiating silica discs (of approximately 5 mm radii and thickness) with a CO2 laser: {lambda} = 10.59 and 4.6 um, Gaussian profile, r{sub 0} = 0.5 mm for 1/e decay. By surrounding the disks in room-temperature air, they make use of the boundary conditions described above.

  17. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    E-Print Network [OSTI]

    Gustavsen, Arild

    2009-01-01T23:59:59.000Z

    Goss. (1998). “Local heat transfer in open frame cavities ofthe local heat transfer in cavities open to the exterior

  18. Esimation of field-scale thermal conductivities of unsaturated rocks from in-situ temperature data

    E-Print Network [OSTI]

    Mukhopadhyay, Sumit; Tsang, Yvonne W.; Birkholzer, Jens T.

    2008-01-01T23:59:59.000Z

    vicinity of the heat source, and rock temperature exceededand the dry rock near the heat source. The other differencesources, heat transfer takes place through the wet rock (see

  19. NOTES AND DISCUSSIONS Note on thermal heating efficiency

    E-Print Network [OSTI]

    Rodriguez, Carlos

    . This is the conversion problem faced in every home, where one has heat from a gas, oil, wood, or coal flame but wants known, fact is of current pedagogical interest and practical importance. © 2003 American Association played a uniquely important role in the development of thermody- namics. There the distinction between

  20. Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process

    E-Print Network [OSTI]

    Zuo, Yanjia

    2010-01-01T23:59:59.000Z

    Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The purpose of the study is to improve the ductility ...

  1. Preparation of silica aerogels with improved mechanical properties and extremely low thermal conductivities through modified sol-gel process .

    E-Print Network [OSTI]

    Zuo, Yanjia

    2010-01-01T23:59:59.000Z

    ??Reported silica aerogels have a thermal conductivity as low as 15 mW/mK. The fragility of silica aerogels, however, makes them impractical for structural applications. The… (more)

  2. Evaluation of the Thermal Performance for a Wire Mesh/Hollow Glass Microsphere Composite Structure as a Conduction Barrier

    E-Print Network [OSTI]

    Mckenna, Sean

    2010-01-15T23:59:59.000Z

    An experimental investigation exploring the use of wire mesh/hollow glass microsphere combination for use as thermal insulation was conducted with the aim to conclude whether or not it represents a superior insulation technology to those...

  3. Efficient Phase-Change Materials: Development of a Low-Cost Thermal Energy Storage System Using Phase-Change Materials with Enhanced Radiation Heat Transfer

    SciTech Connect (OSTI)

    None

    2011-12-05T23:59:59.000Z

    HEATS Project: USF is developing low-cost, high-temperature phase-change materials (PCMs) for use in thermal energy storage systems. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Most PCMs do not conduct heat very well. Using an innovative, electroless encapsulation technique, USF is enhancing the heat transfer capability of its PCMs. The inner walls of the capsules will be lined with a corrosion-resistant, high-infrared emissivity coating, and the absorptivity of the PCM will be controlled with the addition of nano-sized particles. USF’s PCMs remain stable at temperatures from 600 to 1,000°C and can be used for solar thermal power storage, nuclear thermal power storage, and other applications.

  4. When it comes to transporting energy, nature has two vital tools at its disposal: conduction by heat and by

    E-Print Network [OSTI]

    Li, Baowen

    When it comes to transporting energy, nature has two vital tools at its disposal: conduction by heat and by electricity. But these two phenomena have never been treated equally by scientists that have transformed many aspects of our lives. But similar devices that allow the flow of heat

  5. An investigation into the thermal properties of selected sensible and latent heat storage materials

    E-Print Network [OSTI]

    Wood, Stanley Clayton

    1982-01-01T23:59:59.000Z

    in the latent heat of fusion. Considerable work has been done in analyzing latent heat storage systems. Telkes and Raymond [lj did early work with a sodium sulfate system using sealed drums. iVore recent experimental work was conducted with other salt...

  6. An experimental investigation of thermal contact conductance across carbon fiber/epoxy resin composites as a function of interface pressure

    E-Print Network [OSTI]

    Rhoades, Michael Everett

    1989-01-01T23:59:59.000Z

    AN EXPERIMENTAL INVESTIGATION OF THERMAL CONTACT CONDUCTANCE ACROSS CARBON FIBER/EPOXY RESIN COMPOSITES AS A FUNCTION OF INTERFACE PRESSURE A Thesis by MICHAEL EVERETT RHOADES Submitted to the Office of Graduate Studies of Texas A...&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1989 Major Subject: Mechanical Engineering AN EXPERIMENTAL INVESTIGATION OF THERMAL CONTACT CONDUCTANCE ACROSS CARBON FIBER/EPOXY RESIN COMPOSITES AS A...

  7. Minor ion heating in spectra of linearly and circularly polarized Alfvén waves: Thermal and non-thermal motions associated with perpendicular heating

    SciTech Connect (OSTI)

    Dong, Chuanfei, E-mail: dcfy@umich.edu [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States) [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-02-15T23:59:59.000Z

    Minor ion (such as He{sup 2+}) heating via nonresonant interaction with spectra of linearly and circularly polarized Alfvén waves (LPAWs and CPAWs hereafter) is studied. The obtained analytic solutions are in good agreement with the simulation results, indicating that newborn ions are heated by low-frequency Alfvén waves with finite amplitude in low-beta plasmas such as the solar corona. The analytic solutions also reproduce the preferential heating of heavy ions in the solar wind. In the presence of parallel propagating Alfvén waves, turbulence-induced particle motion is clearly observed in the wave (magnetic field) polarized directions. After the waves diminish, the newborn ions are heated, which is caused by the phase difference (randomization) between ions due to their different parallel thermal motions. The heating is dominant in the direction perpendicular to the ambient magnetic field. The perpendicular heating, ?=(T{sub i?}{sup R}?T{sub i0?}{sup R})/T{sub i0?}{sup R} (where T{sub i0?}{sup R} and T{sub i?}{sup R} are the perpendicular temperature of species i before and after genuine heating, respectively), in the spectrum of CPAWs is a factor of two stronger than that of LPAWs. Moreover, we also study the effect of field-aligned differential flow speed of species i relative to H{sup +}, ?v{sub ip}=(v{sub i}?v{sub p})·B/|B| (where v{sub i} and v{sub p} denote vector velocities of the H{sup +} and species i, respectively), on the perpendicular heating. It reveals that large drift speed, v{sub d}=?v{sub ip}, has an effect on reducing the efficiency of perpendicular heating, which is consistent with observations.

  8. Review of combined photovoltaic/thermal collector: solar assisted heat pump system options

    SciTech Connect (OSTI)

    Sheldon, D.B.; Russell, M.C.

    1980-01-01T23:59:59.000Z

    The advantages of using photovoltaic (PV) and combined photovoltaic/thermal (PV/T) collectors in conjunction with residential heat pumps are examined. The thermal and electrical power requirements of similar residences in New York City and Fort Worth are the loads under consideration. The TRNSYS energy balance program is used to simulate the operations of parallel, series, and cascade solar assisted heat pump systems. Similar work involving exclusively thermal collectors is reviewed, and the distinctions between thermal and PV/T systems are emphasized. Provided the defrost problem can be satisfactorily controlled, lifecycle cost analyses show that at both locations the optimum collector area is less than 50 m/sup 2/ and that the parallel system is preferred.

  9. Thermal Fluids

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Thermal Fluids The Thermal Fluids and Heat Transfer program works on thermal hydraulic reactor safety code development and experimental heat transferthermal hydraulics. The...

  10. List of Solar Thermal Process Heat Incentives | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revision hasInformation Earth's Heat JumpInc Place:KeystoneSolarList ofPassive SolarRoofsIncentives Jump to:

  11. Thermal conductance of graphene and dimerite Jin-Wu Jiang,1 Jian-Sheng Wang,1 and Baowen Li1,2,*

    E-Print Network [OSTI]

    Li, Baowen

    Thermal conductance of graphene and dimerite Jin-Wu Jiang,1 Jian-Sheng Wang,1 and Baowen Li1,2,* 1; published 20 May 2009 We investigate the phonon thermal conductance of graphene regarding the graphene sheet as the large-width limit of graphene strips in the ballistic limit. We find that the thermal conductance

  12. Measurement of the Anisotropic Thermal Conductivity of Molybdenum Disulfide Single Crystal by the Time-resolved Magneto-optic Kerr Effect

    E-Print Network [OSTI]

    Cahill, David G.

    with perpendicular magnetization serves as the heater and thermometer in the experiment. The low thermal conductivity for determining the thermal conductivity of materials but the sensitivity of TDTR to the lateral or in-plane thermal conductivity of a sample is low when conventional choices are made for laser spot sizes, #12

  13. High Thermal Conductivity UO2-BeO Nulcear Fuel: Neutronic Performance Assessments and Overview of Fabrication

    E-Print Network [OSTI]

    Naramore, Michael J

    2010-08-03T23:59:59.000Z

    The objective of this work was to evaluate a new high conductivity nuclear fuel form. Uranium dioxide (UO2) is a very effective nuclear fuel, but it’s performance is limited by its low thermal conductivity. The fuel concept considered here is a...

  14. Method of making improved gas storage carbon with enhanced thermal conductivity

    DOE Patents [OSTI]

    Burchell, Timothy D. (Oak Ridge, TN); Rogers, Michael R. (Knoxville, TN)

    2002-11-05T23:59:59.000Z

    A method of making an adsorbent carbon fiber based monolith having improved methane gas storage capabilities is disclosed. Additionally, the monolithic nature of the storage carbon allows it to exhibit greater thermal conductivity than conventional granular activated carbon or powdered activated carbon storage beds. The storage of methane gas is achieved through the process of physical adsorption in the micropores that are developed in the structure of the adsorbent monolith. The disclosed monolith is capable of storing greater than 150 V/V of methane [i.e., >150 STP (101.325 KPa, 298K) volumes of methane per unit volume of storage vessel internal volume] at a pressure of 3.5 MPa (500 psi).

  15. On linearization and preconditioning for radiation diffusion coupled to material thermal conduction equations

    SciTech Connect (OSTI)

    Feng, Tao, E-mail: fengtao2@mail.ustc.edu.cn [School of Mathematical Sciences, University of Science and Technology of China, Hefei 230052 (China) [School of Mathematical Sciences, University of Science and Technology of China, Hefei 230052 (China); Graduate School of China Academy Engineering Physics, Beijing 100083 (China); An, Hengbin, E-mail: an_hengbin@iapcm.ac.cn [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, Xijun, E-mail: yuxj@iapcm.ac.cn [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China)] [National Key Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Li, Qin, E-mail: liqin@lsec.cc.ac.cn [Chinese Academy of Mathematics and Systems Science, Beijing 100190 (China)] [Chinese Academy of Mathematics and Systems Science, Beijing 100190 (China); Zhang, Rongpei, E-mail: zhangrongpei@163.com [Graduate School of China Academy Engineering Physics, Beijing 100083 (China)] [Graduate School of China Academy Engineering Physics, Beijing 100083 (China)

    2013-03-01T23:59:59.000Z

    Jacobian-free Newton–Krylov (JFNK) method is an effective algorithm for solving large scale nonlinear equations. One of the most important advantages of JFNK method is that there is no necessity to form and store the Jacobian matrix of the nonlinear system when JFNK method is employed. However, an approximation of the Jacobian is needed for the purpose of preconditioning. In this paper, JFNK method is employed to solve a class of non-equilibrium radiation diffusion coupled to material thermal conduction equations, and two preconditioners are designed by linearizing the equations in two methods. Numerical results show that the two preconditioning methods can improve the convergence behavior and efficiency of JFNK method.

  16. Power enhancement of heat engines via correlated thermalization in multilevel systems

    E-Print Network [OSTI]

    David Gelbwaser-Klimovsky; Wolfgang Niedenzu; Paul Brumer; Gershon Kurizki

    2014-11-05T23:59:59.000Z

    We analyze a heat machine based on a periodically-driven quantum system permanently coupled to hot and cold baths. It is shown that the maximal power output of a degenerate $V$-type three-level heat engine is that generated by two independent two-level systems. For $N$ levels, this maximal enhancement is $(N-1)$-fold. Hence, level degeneracy is a thermodynamic resource that may effectively boost the power output. The efficiency, however, is not affected. We find that coherence is not an essential asset in multilevel-based heat machines. The existence of multiple thermalization pathways sharing a common ground state suffices for power enhancement.

  17. Development and adaptation of conduction and radiation heat-transfer computer codes for the CFTL. [Core Flow Test Loop; RODCON; HOTTEL

    SciTech Connect (OSTI)

    Conklin, J.C.

    1981-08-01T23:59:59.000Z

    RODCON and HOTTEL are two computational methods used to calculate thermal and radiation heat transfer for the Core Flow Test Loop (CFTL) analysis efforts. RODCON was developed at ORNL to calculate the internal temperature distribution of the fuel rod simulator (FRS) for the CFTL. RODCON solves the time-dependent heat transfer equation in two-dimensional (R angle) cylindrical coordinates at an axial plane with user-specified radial material zones and time- and position-variant surface conditions at the FRS periphery. Symmetry of the FRS periphery boundary conditions is not necessary. The governing elliptic, partial differential heat equation is cast into a fully implicit, finite-difference form by approximating the derivatives with a forward-differencing scheme with variable mesh spacing. The heat conduction path is circumferentially complete, and the potential mathematical problem at the rod center can be effectively ignored. HOTTEL is a revision of an algorithm developed by C.B. Baxi at the General Atomic Company (GAC) to be used in calculating radiation heat transfer in a rod bundle enclosed in a hexagonal duct. HOTTEL uses geometric view factors, surface emissivities, and surface areas to calculate the gray-body or composite view factors in an enclosure having multiple reflections in a nonparticipating medium.

  18. Thermal Economic Analysis of an Underground Water Source Heat Pump System

    E-Print Network [OSTI]

    Zhang, W.; Lin, B.

    2006-01-01T23:59:59.000Z

    The paper presents the thermal economic analysis of an underground water source heat pump system in a high school building based on usage per exergy cost as an evaluation standard, in which the black box model has been used and the cost...

  19. HeatProbe: A Thermal-based Power Meter for Accounting Disaggregated Electricity Usage

    E-Print Network [OSTI]

    Ouhyoung, Ming

    HeatProbe: A Thermal-based Power Meter for Accounting Disaggregated Electricity Usage Bo-Jhang Ho1 Technology Innovation, Academia Sinica 128, Sec. 2, Academia Rd., Taipei 115, Taiwan {cwyou, mschen}@citi.sinica.edu.tw ABSTRACT To promote energy-saving behavior, disaggregating elec- tricity usage is critical for increasing

  20. The development of a solar thermal water purification, heating, and power generation system: A case study.

    E-Print Network [OSTI]

    Wu, Mingshen

    The development of a solar thermal water purification, heating, and power generation system: A case, none of the existing concentrated solar power systems (trough, dish, and tower) that have been the potential of an invention directed to a water purification system that also recovers power from generated

  1. Numerical Simulation of Thermal Performance of Floor Radiant Heating System with Enclosed Phase Change Material

    E-Print Network [OSTI]

    Qiu, L.; Wu, X.

    2006-01-01T23:59:59.000Z

    of the energy storage floor is designed,which places heat pipes in the enclosed phase change material (PCM) layer, without concrete in it. The PCM thermal storage time is studied in relation to the floor surface temperature under different low-temperature hot...

  2. Thermal Energy Storage/Waste Heat Recovery Applications in the Cement Industry

    E-Print Network [OSTI]

    Beshore, D. G.; Jaeger, F. A.; Gartner, E. M.

    1979-01-01T23:59:59.000Z

    , and the Portland Cement Association have studied the potential benefits of using waste heat recovery methods and thermal energy storage systems in the cement manufacturing process. This work was performed under DOE Contract No. EC-77-C-01-50S4. The study has been...

  3. Thermal conduction by dark matter with velocity and momentum-dependent cross-sections

    E-Print Network [OSTI]

    Aaron C. Vincent; Pat Scott

    2014-04-23T23:59:59.000Z

    We use the formalism of Gould and Raffelt to compute the dimensionless thermal conduction coefficients for scattering of dark matter particles with standard model nucleons via cross-sections that depend on the relative velocity or momentum exchanged between particles. Motivated by models invoked to reconcile various recent results in direct detection, we explicitly compute the conduction coefficients $\\alpha$ and $\\kappa$ for cross-sections that go as $v_{\\rm rel}^2$, $v_{\\rm rel}^4$, $v_{\\rm rel}^{-2}$, $q^2$, $q^4$ and $q^{-2}$, where $v_{\\rm rel}$ is the relative DM-nucleus velocity and $q$ is the momentum transferred in the collision. We find that a $v_{\\rm rel}^{-2}$ dependence can significantly enhance energy transport from the inner solar core to the outer core. The same can true for any $q$-dependent coupling, if the dark matter mass lies within some specific range for each coupling. This effect can complement direct searches for dark matter; combining these results with state-of-the-art Solar simulations should greatly increase sensitivity to certain DM models. It also seems possible that the so-called Solar Abundance Problem could be resolved by enhanced energy transport in the solar core due to such velocity- or momentum-dependent scatterings.

  4. MODELING THE TRANSVERSE THERMAL CONDUCTIVITY OF 3D-SICF/SIC COMPOSITES

    SciTech Connect (OSTI)

    Youngblood, Gerald E.; Jones, Russell H.; Yamada, Reiji

    2004-06-30T23:59:59.000Z

    Our previously developed hierarchical two-layer (H2L) model was modified to describe the effective transverse thermal conductivity (Keff) of a three-dimensional (3D) SiC/SiC composite plate made with cross-layered and Z-stitched X:Y:Z uniaxial fiber tow sub-units. As before, the model describes Keff in terms of constituent, microstructural and architectural properties that include the expected effects of fiber-matrix interfacial conductance, of high fiber packing fractions within individual tow sub-units and of the non-uniform porosity contents, shapes and orientations within these sub-units. Model predictions were obtained for two versions of a 3D-Tyranno SA?/PyC/ICVI-SiC composite that had similar fiber/matrix pyrocarbon (PyC) interfaces, relatively high bulk densities (~2.88 g/cc), and an X:Y configuration with fiber content ratios 1:1. The only major difference between the two versions was their Z-stitch fiber content where the relative fiber ratios were 0.1 and 1.2 in the Z sub-units.

  5. Density dependence of the room temperature thermal conductivity of atomic layer deposition-grown amorphous alumina (Al{sub 2}O{sub 3})

    SciTech Connect (OSTI)

    Gorham, Caroline S.; Gaskins, John T.; Hopkins, Patrick E., E-mail: phopkins@virginia.edu [Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Parsons, Gregory N.; Losego, Mark D. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2014-06-23T23:59:59.000Z

    We report on the thermal conductivity of atomic layer deposition-grown amorphous alumina thin films as a function of atomic density. Using time domain thermoreflectance, we measure the thermal conductivity of the thin alumina films at room temperature. The thermal conductivities vary ?35% for a nearly 15% change in atomic density and are substrate independent. No density dependence of the longitudinal sound speeds is observed with picosecond acoustics. The density dependence of the thermal conductivity agrees well with a minimum limit to thermal conductivity model that is modified with a differential effective-medium approximation.

  6. Low-temperature thermal conductivity of antiferromagnetic S?=?1/2 chain material CuCl{sub 2}·2((CH{sub 3}){sub 2}SO)

    SciTech Connect (OSTI)

    Ke, W. P.; Zhang, F. B.; Zhao, Z. Y.; Fan, C.; Sun, X. F., E-mail: xfsun@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shi, J. [Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhao, X., E-mail: xiazhao@ustc.edu.cn [School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-05-07T23:59:59.000Z

    We study the heat transport of S?=?1/2 chain compound CuCl{sub 2}·2((CH{sub 3}){sub 2}SO) along the b axis (vertical to the chain direction) at very low temperatures. The zero-field thermal conductivity (?) shows a distinct kink at about 0.9?K, which is related to the long-range antiferromagnetic (AF) transition. With applying magnetic field along the c axis, ?(H) curves also show distinct changes at the phase boundaries between the AF and the high-field disordered states. These results indicate a strong spin-phonon interaction and the magnetic excitations play a role in the b-axis heat transport as phonon scatterers.

  7. Heating of thermal non-equilibrium ions by Alfvén wave via nonresonant interaction

    SciTech Connect (OSTI)

    Liu, Hai-Feng; Wang, Shi-Qing [Southwestern Institute of Physics, Chengdu 610041 (China) [Southwestern Institute of Physics, Chengdu 610041 (China); The Engineering and Technical College of Chengdu University of Technology, Leshan 614000 (China); Li, Ke-Hua [The Engineering and Technical College of Chengdu University of Technology, Leshan 614000 (China)] [The Engineering and Technical College of Chengdu University of Technology, Leshan 614000 (China)

    2013-10-15T23:59:59.000Z

    Pickup of thermal non-equilibrium ions by Alfvén wave via nonresonant wave-particle interaction is investigated by means of analytical test-particle theory. Some interesting and new results are found. No matter what the initial velocity distribution is, if the background magnetic field, the Alfvén speed, and the Alfvén magnetic field are fixed, the average parallel velocity never changes when t??. Heating effects in the perpendicular and parallel direction just depend on the initial temperature, and the perpendicular temperature increase is more prominent. It is noted that the heating effect of thermal non-equilibrium ions (Kappa ions) is weaker than that of the Maxwellian. This phenomenon may be relative to the heating of ions in the solar corona as well as in some toroidal confinement fusion devices.

  8. Comparison of Different Upscaling Methods for Predicting Thermal Conductivity of Complex Heterogeneous Materials System: Application on Nuclear Waste Forms

    SciTech Connect (OSTI)

    Li, Dongsheng; Sun, Xin; Khaleel, Mohammad A.

    2012-06-16T23:59:59.000Z

    To develop a strategy in thermal conductivity prediction of a complex heterogeneous materials system, loaded nuclear waste forms, the computational efficiency and accuracy of different upscaling methods have been evaluated. The effective thermal conductivity, obtained from microstructure information and local thermal conductivity of different components, is critical in predicting the life and performance of waste form during storage. Several methods, including the Taylor model, Sachs model, self-consistent model, and statistical upscaling method, were developed and implemented. Microstructure based finite element method (FEM) prediction results were used to as benchmark to determine the accuracy of the different upscaling methods. Micrographs from waste forms with varying waste loadings were used in the prediction of thermal conductivity in FEM and homogenization methods. Prediction results demonstrated that in term of efficiency, boundary models (e.g., Taylor model and Sachs model) are stronger than the self-consistent model, statistical upscaling method, and finite element method. However, when balancing computational efficiency and accuracy, statistical upscaling is a useful method in predicting effective thermal conductivity for nuclear waste forms.

  9. Thermal conductivity of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} solid solutions

    SciTech Connect (OSTI)

    Caillat, T.; Borshchevsky, A.; Fleurial, J.P.

    1997-07-01T23:59:59.000Z

    {beta}-Zn{sub 4}Sb{sub 3} was recently identified at the Jet Propulsion Laboratory as a new high performance p-type thermoelectric material with a maximum dimensionless thermoelectric figure of merit ZT of 1.4 at a temperature of 673K. A usual approach, used for many state-of-the-art thermoelectric materials, to further improve ZT values is to alloy {beta}-Zn{sub 4}Sb{sub 3} with isostructural compounds because of the expected decrease in lattice thermal conductivity. The authors have grown Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} crystals with 0.2 {le} x < 1.2 and measured their thermal conductivity from 10 to 500K. The thermal conductivity values of Zn{sub 4{minus}x}Cd{sub x}Sb{sub 3} alloys are significantly lower than those measured for {beta}-Zn{sub 4}Sb{sub 3} and are comparable to its calculated minimum thermal conductivity. A strong atomic disorder is believed to be primarily at the origin of the very low thermal conductivity of these materials which are also fairly good electrical conductors and are therefore excellent candidates for thermoelectric applications.

  10. Tunable thermal link

    DOE Patents [OSTI]

    Chang, Chih-Wei; Majumdar, Arunava; Zettl, Alexander K.

    2014-07-15T23:59:59.000Z

    Disclosed is a device whereby the thermal conductance of a multiwalled nanostructure such as a multiwalled carbon nanotube (MWCNT) can be controllably and reversibly tuned by sliding one or more outer shells with respect to the inner core. As one example, the thermal conductance of an MWCNT dropped to 15% of the original value after extending the length of the MWCNT by 190 nm. The thermal conductivity returned when the tube was contracted. The device may comprise numbers of multiwalled nanotubes or other graphitic layers connected to a heat source and a heat drain and various means for tuning the overall thermal conductance for applications in structure heat management, heat flow in nanoscale or microscale devices and thermal logic devices.

  11. Thermophysical Properties of Heat Resistant Shielding Material

    SciTech Connect (OSTI)

    Porter, W.D.

    2004-12-15T23:59:59.000Z

    This project was aimed at determining thermal conductivity, specific heat and thermal expansion of a heat resistant shielding material for neutron absorption applications. These data are critical in predicting the structural integrity of the shielding under thermal cycling and mechanical load. The measurements of thermal conductivity and specific heat were conducted in air at five different temperatures (-31 F, 73.4 F, 140 F, 212 F and 302 F). The transient plane source (TPS) method was used in the tests. Thermal expansion tests were conducted using push rod dilatometry over the continuous range from -40 F (-40 C) to 302 F (150 C).

  12. Ultra-Low Thermal Conductivity in W/Al2O3 Nanolaminates

    E-Print Network [OSTI]

    George, Steven M.

    conversion (3). Conversely, the thermal resistance of interfaces degrades the performance of materials dissimilar materials may provide a route for the production of thermal barriers with ultra-low thermal and improve the performance of thermal bar- riers (2) and of materials used in thermoelec- tric energy

  13. THERMAL NON-EQUILIBRIUM REVISITED: A HEATING MODEL FOR CORONAL LOOPS

    SciTech Connect (OSTI)

    Lionello, Roberto; Linker, Jon A.; Mikic, Zoran [Predictive Science, Inc., 9990 Mesa Rim Rd., Ste. 170, San Diego, CA 92121-2910 (United States); Winebarger, Amy R. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Mok, Yung, E-mail: lionel@predsci.com, E-mail: linkerj@predsci.com, E-mail: mikicz@predsci.com, E-mail: amy.r.winebarger@nasa.gov, E-mail: ymok@uci.edu [Department of Physics and Astronomy, University of California, 4129 Reines Hall, Irvine, CA 92697 (United States)

    2013-08-20T23:59:59.000Z

    The location and frequency of events that heat the million-degree corona are still a matter of debate. One potential heating scenario is that the energy release is effectively steady and highly localized at the footpoints of coronal structures. Such an energy deposition drives thermal non-equilibrium solutions in the hydrodynamic equations in longer loops. This heating scenario was considered and discarded by Klimchuk et al. on the basis of their one-dimensional simulations as incapable of reproducing observational characteristics of loops. In this paper, we use three-dimensional simulations to generate synthetic emission images, from which we select and analyze six loops. The main differences between our model and that of Klimchuk et al. concern (1) dimensionality, (2) resolution, (3) geometrical properties of the loops, (4) heating function, and (5) radiative function. We find evidence, in this small set of simulated loops, that the evolution of the light curves, the variation of temperature along the loops, the density profile, and the absence of small-scale structures are compatible with the characteristics of observed loops. We conclude that quasi-steady footpoint heating that drives thermal non-equilibrium solutions cannot yet be ruled out as a viable heating scenario for EUV loops.

  14. Pressurized heat treatment of glass-ceramic to control thermal expansion

    DOE Patents [OSTI]

    Kramer, Daniel P. (Dayton, OH)

    1985-01-01T23:59:59.000Z

    A method of producing a glass-ceramic having a specified thermal expansion value is disclosed. The method includes the step of pressurizing the parent glass material to a predetermined pressure during heat treatment so that the glass-ceramic produced has a specified thermal expansion value. Preferably, the glass-ceramic material is isostatically pressed. A method for forming a strong glass-ceramic to metal seal is also disclosed in which the glass-ceramic is fabricated to have a thermal expansion value equal to that of the metal. The determination of the thermal expansion value of a parent glass material placed in a high-temperature environment is also used to determine the pressure in the environment.

  15. Survey and evaluation of available thermal insulation materials for use on solar heating and cooling systems

    SciTech Connect (OSTI)

    Not Available

    1980-03-01T23:59:59.000Z

    This is the final report of a survey and evaluation of insulation materials for use with components of solar heating and cooling systems. The survey was performed by mailing questionnaires to manufacturers of insulation materials and by conducting an extensive literature search to obtain data on relevant properties of various types of insulation materials. The study evaluated insulation materials for active and passive solar heating and cooling systems and for multifunction applications. Primary and secondary considerations for selecting insulation materials for various components of solar heating and cooling systems are presented.

  16. Effective Thermal Conductivity of a Li{sub 2}TiO{sub 3} Pebble Bed for a DEMO Blanket

    SciTech Connect (OSTI)

    Hatano, T.; Enoeda, M.; Suzuki, S.; Kosaku, Y.; Akiba, M. [Japan Atomic Energy Research Institute (Japan)

    2003-07-15T23:59:59.000Z

    In development of the ceramic breeder blanket, the effective thermal conductivity of pebble beds is an important design parameter. For thermo-mechanical design of blanket, pebble beds were investigated used for Li{sub 2}TiO{sub 3} that was a candidate for tritium breeder. Li{sub 2}TiO{sub 3} pebble beds, whose size was 0.28-1.91 mm diameter, were measured on load under no neutron irradiation. The effective thermal conductivity was increased with load increasing was obtained.

  17. Photothermal measurement of the thermal conductivity of supercooled water O. Benchikh, D. Fournier, A. C. Boccara

    E-Print Network [OSTI]

    Boyer, Edmond

    Thermal diffusivity measurements of supercooled water have been performed between + 40 °C and - 23 °C properties of supercooled water have been measured [1 ]. However, the thermal conduc- Article published

  18. Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Horizontal Window Frames with Internal Cavities

    SciTech Connect (OSTI)

    Gustavsen, Arlid; Kohler, Christian; Dalehaug, Arvid; Arasteh, Dariush

    2008-12-01T23:59:59.000Z

    This paper assesses the accuracy of the simplified frame cavity conduction/convection and radiation models presented in ISO 15099 and used in software for rating and labeling window products. Temperatures and U-factors for typical horizontal window frames with internal cavities are compared; results from Computational Fluid Dynamics (CFD) simulations with detailed radiation modeling are used as a reference. Four different frames were studied. Two were made of polyvinyl chloride (PVC) and two of aluminum. For each frame, six different simulations were performed, two with a CFD code and four with a building-component thermal-simulation tool using the Finite Element Method (FEM). This FEM tool addresses convection using correlations from ISO 15099; it addressed radiation with either correlations from ISO 15099 or with a detailed, view-factor-based radiation model. Calculations were performed using the CFD code with and without fluid flow in the window frame cavities; the calculations without fluid flow were performed to verify that the CFD code and the building-component thermal-simulation tool produced consistent results. With the FEM-code, the practice of subdividing small frame cavities was examined, in some cases not subdividing, in some cases subdividing cavities with interconnections smaller than five millimeters (mm) (ISO 15099) and in some cases subdividing cavities with interconnections smaller than seven mm (a breakpoint that has been suggested in other studies). For the various frames, the calculated U-factors were found to be quite comparable (the maximum difference between the reference CFD simulation and the other simulations was found to be 13.2 percent). A maximum difference of 8.5 percent was found between the CFD simulation and the FEM simulation using ISO 15099 procedures. The ISO 15099 correlation works best for frames with high U-factors. For more efficient frames, the relative differences among various simulations are larger. Temperature was also compared, at selected locations on the frames. Small differences was found in the results from model to model. Finally, the effectiveness of the ISO cavity radiation algorithms was examined by comparing results from these algorithms to detailed radiation calculations (from both programs). Our results suggest that improvements in cavity heat transfer calculations can be obtained by using detailed radiation modeling (i.e. view-factor or ray-tracing models), and that incorporation of these strategies may be more important for improving the accuracy of results than the use of CFD modeling for horizontal cavities.

  19. 1D-to-3D transition of photon heat conduction in polyethylene using molecular dynamics simulations

    E-Print Network [OSTI]

    Henry, Asegun Sekou Famake

    2009-01-01T23:59:59.000Z

    Experiments have demonstrated that the mechanical stretching of bulk polyethylene can increase its thermal conductivity by more than two orders of magnitude, from 0.35 W/mK to over 40W/mK, which is comparable to steel. ...

  20. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    537°C) steam for the steam turbine to generate electricity.as heat sources for steam turbines. Mainly three approachesto Stirling or Brayton steam turbine, moderate to high heat

  1. The integration of water loop heat pump and building structural thermal storage systems

    SciTech Connect (OSTI)

    Marseille, T.J.; Schliesing, J.S.

    1991-10-01T23:59:59.000Z

    Many commercial buildings need heat in one part and, at the same time, cooling in another part. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If that energy could be shifted or stored for later use, significant energy might be saved. If a building's heating and cooling subsystems could be integrated with the building's structural mass and used to collect, store, and deliver energy, the energy might be save cost-effectively. To explore this opportunity, researchers at the Pacific Northwest Laboratory (PNL) examined the thermal interactions between the heating, ventilating, and air-conditioning (HVAC) system and the structure of a commercial building. Computer models were developed to simulate the interactions in an existing building located in Seattle, Washington, to determine how these building subsystems could be integrated to improve energy efficiency. The HVAC subsystems in the existing building were modeled. These subsystems consist of decentralized water-source heat pumps (WSHP) in a closed water loop, connected to cooling towers for heat rejection during cooling mode and boilers to augment heating. An initial base case'' computer model of the Seattle building, as-built, was developed. Metered data available for the building were used to calibrate this model to ensure that the analysis would provide information that closely reflected the operation of a real building. The HVAC system and building structure were integrated in the model using the concrete floor slabs as thermal storage media. The slabs may be actively charged during off-peak periods with the chilled water in the loop and then either actively or passively discharged into the conditioned space during peak periods. 21 refs., 37 figs., 17 tabs.

  2. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    E-Print Network [OSTI]

    Gustavsen, Arild

    2009-01-01T23:59:59.000Z

    contours for one of the PVC frames studied by Gustavsen etframe with a polyvinyl chloride (PVC ) thermal breakand a PVC frame] were examined with air leakage rates of

  3. Eurotherm Seminar N81 Reactive Heat Transfer in Porous Media, Ecole des Mines d'Albi, France June 4-6, 2007 ET81-1 HEAT TRANSFER BY SIMULTANEOUS RADIATION-CONDUCTION

    E-Print Network [OSTI]

    Boyer, Edmond

    Eurotherm Seminar N°81 Reactive Heat Transfer in Porous Media, Ecole des Mines d'Albi, France June 4-6, 2007 ET81- 1 HEAT TRANSFER BY SIMULTANEOUS RADIATION-CONDUCTION AND CONVECTION IN A HIGH for the packed bed. The comparison between the radiative heat transfer and the exchanges by conduction and forced

  4. Thermal radiation of laser heated niobium clusters Nb{sub N}{sup +}, 8 ? N ? 22

    SciTech Connect (OSTI)

    Hansen, Klavs [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Li, Yejun; Kaydashev, Vladimir; Janssens, Ewald [Laboratory of Solid State Physics and Magnetism, KU Leuven, B-3001 Leuven (Belgium)

    2014-07-14T23:59:59.000Z

    The thermal radiation from small, laser heated, positively charged niobium clusters has been measured. The emitted power was determined by the quenching effect on the metastable decay, employing two different experimental protocols. The radiative power decreases slightly with cluster size and shows no strong size-to-size variations. The magnitude is 40–50 keV/s at the timescale of several microseconds, which is the measured crossover time from evaporative to radiative cooling.

  5. Microstructural characterization and microstructural effects on the thermal conductivity of AlN(Y2O3) ceramics

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    Microstructural characterization and microstructural effects on the thermal conductivity of AlN(Y2O3) ceramics Ying-Da Yu a , Aase Marie Hundere b , Ragnvald Høier a , Rafal E. Dunin-Borkowski c aluminum nitride (AlN) ceramic materials with Y2O3 as a sintering additive have been sintered at 1880 C

  6. Effective Thermal Conductivity of Soda-Lime Silicate Glassmelts with Different Iron Contents Between 1100C and 1500C

    E-Print Network [OSTI]

    Pilon, Laurent

    Effective Thermal Conductivity of Soda-Lime Silicate Glassmelts with Different Iron Contents collected for soda- lime silicate glasses with iron content ranging from 0.008 to 1.1 wt% and temperatures, refractory walls wear more rapidly for clear glassmelts compared with colored ones.1 Soda-lime silicate glass

  7. Use of impure inert gases in the controlled heating and cooling of mixed conducting metal oxide materials

    DOE Patents [OSTI]

    Carolan, Michael Francis (Allentown, PA); Bernhart, John Charles (Fleetwood, PA)

    2012-08-21T23:59:59.000Z

    Method for processing an article comprising mixed conducting metal oxide material. The method comprises contacting the article with an oxygen-containing gas and either reducing the temperature of the oxygen-containing gas during a cooling period or increasing the temperature of the oxygen-containing gas during a heating period; during the cooling period, reducing the oxygen activity in the oxygen-containing gas during at least a portion of the cooling period and increasing the rate at which the temperature of the oxygen-containing gas is reduced during at least a portion of the cooling period; and during the heating period, increasing the oxygen activity in the oxygen-containing gas during at least a portion of the heating period and decreasing the rate at which the temperature of the oxygen-containing gas is increased during at least a portion of the heating period.

  8. Thermal conductivity of the quark matter for the SU(2) light-flavor sector

    E-Print Network [OSTI]

    Seung-il Nam

    2015-03-04T23:59:59.000Z

    We investigate the thermal conductivity ($\\kappa$) of the quark matter at finite quark chemical potential $(\\mu)$ and temperature $(T)$, employing the Green-Kubo formula, for the SU(2) light-flavor sector with the finite current-quark mass $m=5$ MeV. As a theoretical framework, we construct an effective thermodynamic potential from the $(\\mu,T)$-modified liquid-instanton model (mLIM). Note that all the relevant model parameters are designated as functions of $T$, using the trivial-holonomy caloron solution. By solving the self-consistent equation of mLIM, we acquire the constituent-quark mass $M_0$ as a function of $T$ and $\\mu$, satisfying the universal-class patterns of the chiral phase transition. From the numerical results for $\\kappa$, we observe that there emerges a peak at $\\mu\\approx200$ MeV for the low-$T$ region, i.e. $T\\lesssim100$ MeV. As $T$ increase over $T\\approx100$ MeV, the curve for $\\kappa$ is almost saturated as a function of $T$ in the order of $\\sim10^{-1}\\,\\mathrm{GeV}^2$, and grows with respect to $\\mu$ smoothly. At the normal nuclear-matter density $\\rho_0=0.17\\,\\mathrm{fm}^{-3}$, $\\kappa$ shows its maximum $6.22\\,\\mathrm{GeV}^2$ at $T\\approx10$ MeV, then decreases exponentially down to $\\kappa\\approx0.2\\,\\mathrm{GeV}^2$. We also compute the ratio of $\\kappa$ and the entropy density, i.e. $\\kappa/s$ as a function of $(\\mu,T)$ which is a monotonically decreasing function for a wide range of $T$, then approaches a lower bound at very high $T$: $\\kappa/s_\\mathrm{min}\\gtrsim0.3\\,\\mathrm{GeV}^{-1}$ in the vicinity of $\\mu=0$.

  9. Temperature and thermal stress distributions for the HFIR permanent reflector generated by nuclear heating

    SciTech Connect (OSTI)

    Chang, S.J.

    1998-04-01T23:59:59.000Z

    The beryllium permanent reflector of the High Flux Isotope Reactor has the main functions for slowing down and reflecting the neutrons and housing the experimental facilities. The reflector is heated as a result of the nuclear reaction. Heat is removed mainly by the cooling water passing through the densely distributed coolant holes along the vertical or axial direction of the reflector. The reflector neutronic distribution and its heating rate are calculated by J.C. Gehin of the Oak Ridge National Laboratory by applying the Monte Carlo Code MCNP. The heat transfer boundary conditions along several reflector interfaces are estimated to remove additional heat from the reflector. The present paper is to report the calculation results of the temperature and the thermal stress distributions of the permanent reflector by applying the computer aided design code I-DEAS and the finite element code ABAQUS. The present calculation is to estimate the high stress areas as a result of the new beam tube cutouts along the horizontal mid-plane of the reflector of the recent reactor upgrade project. These high stresses were not able to be calculated in the preliminary design analysis in earlier 60`s. The heat transfer boundary conditions are used in this redesigned calculation. The material constants and the acceptance criteria for the allowable stresses are mainly based on that assumed in the preliminary design report.

  10. Effect of metallic coatings on the thermal contact conductance of turned surfaces

    E-Print Network [OSTI]

    Kang, Tik Kwie

    2012-06-07T23:59:59.000Z

    area. . IInfortunately this is not always possible, due to design or load restrictions In situations where the applied load is limited. the thermal contact resistance can be reduced by introducing a material at the interface that is relatively sof... materials on thermal contact resistance both analytically and experimen- tally for a. fixed geometry and material. In the analytical portion, the approximate relative reduction of the thermal contact resistance due to plating was described as ~plating (u...

  11. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    Thermal energy storage for sustainable energy consumption –Sustainable Energy, Cambridge University Press, 65- Dermott A.M, Frysinger G.R, Storage

  12. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    analyzed a built-in, storage-type water heater containing astorage and thermal protection that can operate with PCM technology. Among them are building insulators, water heaters,

  13. Fundamental heat transfer processes related to phase change thermal storage media

    SciTech Connect (OSTI)

    Sparrow, E. M.; Ramsey, J. W.

    1981-01-01T23:59:59.000Z

    Research on fundamental heat transfer processes which occur in phase-change thermal storage systems is described. The research encompasses both melting and freezing, and includes both experiment and analysis. The status of four research problems is discussed. One of the freezing problems was focused on investigating, via experiment, the extent to which freezing can be enhanced by the attachment of fins to the external surface of a cooled vertical tube situated in a liquid phase-change medium. Very substantial enhancements were encountered which neutralize the degradation of freezing due to the thermal resistance of the frozen layer and to natural convection in the liquid phase. The second of the freezing problems was analytical in nature and sought to obtain solutions involving both the phase-change medium and the heat transfer fluid used either to add heat to or extract heat from the medium. For freezing on a plane wall, it was possible to obtain a closed-form analytical solution, while for freezing about a coolant-carrying circular tube, a new numerical methodology was devised to obtain finite-difference solutions. For melting, quantitative design-quality heat transfer coefficients were determined experimentally for melting adjacent to a heated vertical tube. These experiments explored the effects of solid-phase subcooling and of open versus closed top containment on the coefficients. A dimensionless correlation enables these results to be used for a wide range of phase-change media. Studies on melting of a phase-change material situated within a circular tube are in progress.

  14. Thermal Conductivity Enhancement of High Temperature Phase Change Materials for Concentrating Solar Power Plant Applications

    E-Print Network [OSTI]

    Roshandell, Melina

    2013-01-01T23:59:59.000Z

    been heated at solar collection tower, at the temperatureIn the receiver tower, the collected solar radiation heatsfocus and send solar radiation to a receiver tower.

  15. E-Print Network 3.0 - anomalous thermal conductivity Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Engineering, University of Tokyo Collection: Materials Science 3 MECHANICAL AND AEROSPACE ENGINEERING COLLOQUIUM SERIES Summary: on heat transfer. To inform a debate on anomalous...

  16. PUBLISHED ONLINE: 9 MAY 2010 | DOI: 10.1038/NMAT2753 Dimensional crossover of thermal transport in

    E-Print Network [OSTI]

    on heat conduction in low-dimensional materials and may open up FLG applications in thermal management , is heat conduction in low- dimensional materials. The question of what happens with thermal conductivity unique electronic2,3 and optical properties4 , reveals unusually high thermal conductivity5,6 . The fact

  17. REVIEW ARTIC LE MICROSCALE THERMAL BUBBLE FORMATION

    E-Print Network [OSTI]

    Lin, Liwei

    8 C a thermal diffusivity, m r s 8 C 2 F excess heat conduction shape factor e variable in the heat, and this article discusses microscale bubble formation by using polysilicon microheaters. Figure 1a shows

  18. Conduction cooling: multicrate fastbus hardware

    SciTech Connect (OSTI)

    Makowiecki, D.; Sims, W.; Larsen, R.

    1980-11-01T23:59:59.000Z

    Described is a new and novel approach for cooling nuclear instrumentation modules via heat conduction. The simplicity of liquid cooled crates and ease of thermal management with conduction cooled modules are described. While this system was developed primarily for the higher power levels expected with Fastbus electronics, it has many general applications.

  19. Some aspects of the computer simulation of conduction heat transfer and phase change processes

    SciTech Connect (OSTI)

    Solomon, A. D.

    1982-04-01T23:59:59.000Z

    Various aspects of phase change processes in materials are discussd including computer modeling, validation of results and sensitivity. In addition, the possible incorporation of cognitive activities in computational heat transfer is examined.

  20. An experimental and theoretical study of radiative and conductive heat transfer in nongray semitransparent media

    E-Print Network [OSTI]

    Eryou, N. Dennis

    1969-01-01T23:59:59.000Z

    One dimensional temperature profiles and heat fluxes within a slab of molten glass were measured experimentally. The glass slab was contained in a platinum foil lined ceramic tray inside a high temperature furnace. An ...

  1. Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation

    SciTech Connect (OSTI)

    Janne Pakrinen; Marat Khafizov; Lingfeng He; Chris Wetland; Jian Gan; Andrew T. Nelson; David H Hurley; Anter El-Azab; Todd R Allen

    2014-11-01T23:59:59.000Z

    The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in x-ray diffraction after ion irradiation up to 5×1016 He2+/cm2 at low-temperature (< 200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 µm thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 µm) in the sample subjected to 5×1016 He2+/cm2, the highest fluence reached, while similar features were not detected at 9×1015 He2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55 % for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.

  2. In-Situ Thermal Conductivity Testing Using a Portable Heat Flow Meter

    E-Print Network [OSTI]

    Harr, K. S.; Hutto, F. B., Jr.

    1979-01-01T23:59:59.000Z

    suspicion of the approaching energy revolution. To achieve their energy efficiency objectives, virtually all progressive companies have utilized several common program essentials. First, and certainly foremost of these essentials, is the matter of company...

  3. Temperature, thermal-conductivity, and heat-flux data,Raft River area,

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home5b9fcbce19 No revisionEnvReviewNonInvasiveExplorationUT-gTaguspark Jump to: navigation,Telluric Survey DetailsCassia County,

  4. A fully second order implicit/explicit time integration technique for hydrodynamics plus nonlinear heat conduction problems

    SciTech Connect (OSTI)

    Kadioglu, Samet Y. [Multiphysics Methods Group, Reactor Physics Analysis and Design, Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States)], E-mail: Samet.Kadioglu@inl.gov; Knoll, Dana A. [Multiphysics Methods Group, Reactor Physics Analysis and Design, Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States)], E-mail: dana.knoll@inl.gov

    2010-05-01T23:59:59.000Z

    We present a fully second order implicit/explicit time integration technique for solving hydrodynamics coupled with nonlinear heat conduction problems. The idea is to hybridize an implicit and an explicit discretization in such a way to achieve second order time convergent calculations. In this scope, the hydrodynamics equations are discretized explicitly making use of the capability of well-understood explicit schemes. On the other hand, the nonlinear heat conduction is solved implicitly. Such methods are often referred to as IMEX methods. The Jacobian-Free Newton Krylov (JFNK) method (e.g. ) is applied to the problem in such a way as to render a nonlinearly iterated IMEX method. We solve three test problems in order to validate the numerical order of the scheme. For each test, we established second order time convergence. We support these numerical results with a modified equation analysis (MEA). The set of equations studied here constitute a base model for radiation hydrodynamics.

  5. A comparison of two heat transfer models for estimating thermal drawdown in Hot Dry Rock reservoirs

    SciTech Connect (OSTI)

    Robinson, Bruce A.; Kruger, Paul

    1988-01-01T23:59:59.000Z

    Estimates of thermal drawdown in Hot Dry Rock geothermal systems have been made with two different models of heat transfer from hydraulically fractured reservoir rock blocks to water circulated through the fracture permeability. One model is based on deconvolution of experimental tracer response curves into a network of flowpaths connected in parallel with heat transfer calculated individually in each flowpath. The second model is based on one-dimensional flow through the rock with a block size distribution described as a group of equivalent-radius spheres for which the heat transfer equations can be solved analytically. The two models were applied to the planned Phase II long-term thermal drawdown experiment at Fenton Hill, NM. The results show good agreement between the two models, with estimates of temperature cooldown from 240ºC to 150ºC in a few years depending on selected operation parameters, but with somewhat differing cooldown curve characteristic shapes. Data from the long-term experiment will be helpful in improving the two models.

  6. Estimation of composite thermal conductivity of a heterogeneous methane hydrate sample using iTOUGH2

    E-Print Network [OSTI]

    Gupta, Arvind; Kneafsey, Timothy J.; Moridis, George J.; Seol, Yongkoo; Kowalsky, Michael B.; Sloan Jr., E.D.

    2006-01-01T23:59:59.000Z

    International Conference on Gas Hydrates, Trondheim, Norway,Challenges for the future/gas hydrates, NYAS 912, 304, 2000.C. , Thermal state of the gas hydrate reservoir, natural gas

  7. Heat blanketing envelopes and thermal radiation of strongly magnetized neutron stars

    E-Print Network [OSTI]

    A. Y. Potekhin; G. Chabrier; D. G. Yakovlev

    2007-09-04T23:59:59.000Z

    Strong (B >> 10^9 G) and superstrong (B > 10^{14} G) magnetic fields profoundly affect many thermodynamic and kinetic characteristics of dense plasmas in neutron star envelopes. In particular, they produce strongly anisotropic thermal conductivity in the neutron star crust and modify the equation of state and radiative opacities in the atmosphere, which are major ingredients of the cooling theory and spectral atmosphere models. As a result, both the radiation spectrum and the thermal luminosity of a neutron star can be affected by the magnetic field. We briefly review these effects and demonstrate the influence of magnetic field strength on the thermal structure of an isolated neutron star, putting emphasis on the differences brought about by the superstrong fields and high temperatures of magnetars. For the latter objects, it is important to take proper account of a combined effect of the magnetic field on thermal conduction and neutrino emission at densities \\rho > 10^{10} g cm^{-3}. We show that the neutrino emission puts a B-dependent upper limit on the effective surface temperature of a cooling neutron star.

  8. Transport modeling of simple fluids and nano-colloids : thermal conduction mechanisms and coarse projection

    E-Print Network [OSTI]

    Eapen, Jacob, 1968-

    2006-01-01T23:59:59.000Z

    In the first part of this thesis, the modes of microscopic energy fluctuations governing heat flow in nano-colloids are quantitatively assessed by combining linear response theory with molecular dynamics (MD) simulations. ...

  9. Thermal cycling effect on the nanoparticle distribution and specific heat of a carbonate eutectic with alumina nanoparticles

    E-Print Network [OSTI]

    Shankar, Sandhya

    2011-08-08T23:59:59.000Z

    . The concentration of alumina nanoparticles in this material was measured using neutron activation analysis. The average specific heat of the uncycled material was found to be 1.37 J/g°C.The average specific heat of the thermally cycled material was between 1.7-2.1 J...

  10. HeatProbe: a Thermal-based Power Meter System for Tracking Per-user Power Consumption

    E-Print Network [OSTI]

    Chu, Hao-hua

    HeatProbe: a Thermal-based Power Meter System for Tracking Per-user Power Consumption Nan-Chen Chen Technology Innovation, Academic Sinica2 {b97006, b96118, b95701241}@csie.ntu.edu.tw, cwyou@citi.sinica.edu.tw, hchu@csie.ntu.edu.tw, mschen@citi.sinica.edu.tw Abstract. This paper proposes HeatProbe, a per

  11. Long Term Thermal Stability In Air Of Ionic Liquid Based Alternative Heat Transfer Fluids For Clean Energy Production

    SciTech Connect (OSTI)

    Fox, Elise B; Kendrick, Sarah E.; Visser, Ann E.; Bridges, Nicholas J.

    2012-10-15T23:59:59.000Z

    The purpose of this study was to investigate the effect of long-term aging on the thermal stability and chemical structure of seven different ILs so as to explore their suitability for use as a heat transfer fluid. This was accomplished by heating the ILs for 15 weeks at 200?C in an oxidizing environment and performing subsequent analyses on the aged chemicals.

  12. Fluid Circulation and Heat Extraction from Engineered Geothermal...

    Open Energy Info (EERE)

    from Engineered Geothermal Reservoirs Abstract A large amount of fluid circulation and heat extraction (i.e., thermal power production) research and testing has been conducted...

  13. AN EXPERIMENTAL AND THEORETICAL STUDY OF HEAT TRANSFER WITH COMBUSTION

    E-Print Network [OSTI]

    Heperkan, Hasan A.

    2013-01-01T23:59:59.000Z

    specific heat of ceramic thermal conductivity of ceramic kwthermal penetration depth is much smaller than the characterlstic dimensions of the gauge. The ceramic

  14. Interplay of point defects, biaxial strain, and thermal conductivity in homoepitaxial SrTiO{sub 3} thin films

    SciTech Connect (OSTI)

    Wiedigen, S.; Kramer, T.; Knorr, I.; Nee, N.; Hoffmann, J.; Volkert, C. A.; Jooss, Ch. [University of Goettingen, Institute of Materials Physics, Friedrich-Hund-Platz 1, 37077 Goettingen (Germany); Feuchter, M.; Kamlah, M. [Karlsruhe Institute of Technology, Institute for Applied Materials, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2012-02-06T23:59:59.000Z

    Separating out effects of point defects and lattice strain on thermal conductivity is essential for improvement of thermoelectric properties of SrTiO{sub 3}. We study relations between defects generated during deposition, induced lattice strain, and their impact on thermal conductivity {kappa} in homoepitaxial SrTiO{sub 3} films prepared by ion-beam sputtering. Lowering the deposition temperature gives rise to lattice expansion by enhancement of point defect density which increases the hardness of the films. Due to a fully coherent substrate-film interface, the lattice misfit induces a large biaxial strain. However, we can show that the temperature dependence of {kappa} is mainly sensitive on the defect concentration.

  15. RELAP5/MOD3 simulation of the loss of residual heat removal during midloop operation experiment conducted at the ROSA-IV/ Large Scale Test Facility

    E-Print Network [OSTI]

    Banerjee, Sibashis Sanatkumar

    2012-06-07T23:59:59.000Z

    The modeling of the complex thermal hydraulics Of reactor systems involves the use Of experimental test systems as well as numerical codes. A simulation of the loss of residual heat removal (RHR) during midloop operations was performed using...

  16. An experimental study of endwall heat transfer enhancement for flow past staggered non-conducting pin fin arrays

    E-Print Network [OSTI]

    Achanta, Vamsee Satish

    2004-09-30T23:59:59.000Z

    : : : : : : : : : : : : : : : : : : : : : : : : 15 VI RESULTS AND DISCUSSION : : : : : : : : : : : : : : : : : : : 17 A. Effect of Reynolds Number ReDh . . . . . . . . . . . . . . 17 B. Effect of Height of Pins, H=D . . . . . . . . . . . . . . . . 21 C. Effect of Stream Wise Spacing of Pins, SL=D... Pressure Drop for D = 2:54cm : 23 9 Effect of H=D on Thermal Performance for D = 2:54cm : : : : : : : 24 10 Effect of SL=D on Heat Transfer Enhancement for D=1.27cm : : : : 25 11 Effect of SL=D on Increase of Overall Pressure Drop for D = 1:27cm 26 12...

  17. Thermoeconomic optimization of sensible heat thermal storage for cogenerated waste-to-energy recovery

    SciTech Connect (OSTI)

    Abdul-Razzak, H.A. [Texas A and M Univ., Kingsville, TX (United States). Dept. of Mechanical and Industrial Engineering; Porter, R.W. [Illinois Inst. of Tech., chicago, IL (United States). Dept. of Mechanical and Aerospace Engineering

    1995-10-01T23:59:59.000Z

    This paper investigates the feasibility of employing thermal storage for cogenerated waste-to-energy recovery such as using mass-burning water-wall incinerators and topping steam turbines. Sensible thermal storage is considered in rectangular cross-sectioned channels through which is passed unused process steam at 1,307 kPa/250 C (175 psig/482 F) during the storage period and feedwater at 1,307 kPa/102 C (175 psig/216 F) during the recovery period. In determining the optimum storage configuration, it is found that the economic feasibility is a function of mass and specific heat of the material and surface area of the channel as well as cost of material and fabrication. Economic considerations included typical cash flows of capital charges, energy revenues, operation and maintenance, and income taxes. Cast concrete is determined to be a potentially attractive storage medium.

  18. The Added Economic and Environmental Value of Solar Thermal Systems in Microgrids with CombinedHeat and Power

    SciTech Connect (OSTI)

    Marnay, Chris; Stadler, Michael; Cardoso, Goncalo; Megel, Olivier; Lai, Judy; Siddiqui, Afzal

    2009-08-15T23:59:59.000Z

    The addition of solar thermal and heat storage systems can improve the economic, as well as environmental attraction of micro-generation systems, e.g. fuel cells with or without combined heat and power (CHP) and contribute to enhanced CO2 reduction. However, the interactions between solar thermal collection and storage systems and CHP systems can be complex, depending on the tariff structure, load profile, etc. In order to examine the impact of solar thermal and heat storage on CO2 emissions and annual energy costs, a microgrid's distributed energy resources (DER) adoption problem is formulated as a mixed-integer linear program. The objective is minimization of annual energy costs. This paper focuses on analysis of the optimal interaction of solar thermal systems, which can be used for domestic hot water, space heating and/or cooling, and micro-CHP systems in the California service territory of San Diego Gas and Electric (SDG&E). Contrary to typical expectations, our results indicate that despite the high solar radiation in southern California, fossil based CHP units are dominant, even with forecast 2020 technology and costs. A CO2 pricing scheme would be needed to incent installation of combined solar thermal absorption chiller systems, and no heat storage systems are adopted. This research also shows that photovoltaic (PV) arrays are favored by CO2 pricing more than solar thermal adoption.

  19. ORNL rod-bundle heat-transfer test data. Volume 6. Thermal-hydraulic test facility experimental data report for test 3. 05. 5B - double-ended cold-leg break simulation

    SciTech Connect (OSTI)

    Mullins, C.B.; Felde, D.K.; Sutton, A.G.; Gould, S.S.; Morris, D.G.; Robinson, J.J.; Schwinkendorf, K.N.

    1982-05-18T23:59:59.000Z

    Thermal-Hydraulic Test Facility (THTF) Test 3.05.5B was conducted by members of the ORNL PWR Blowdown Heat Transfer Separate-Effects Program on July 3, 1980. The objective of the program is to investigate heat transfer phenomena believed to occur in PWRs during accidents, including small and large break loss-of-coolant accidents. Test 3.05.5B was designed to provide transient thermal-hydraulics data in rod bundle geometry under reactor accident-type conditions. Reduced instrument responses are presented. Also included are uncertainties in the instrument responses, calculated mass flows, and calculated rod powers.

  20. Effects of axial plate heat conduction on the thermal performance of a laminar counterflow flat plate heat exchanger

    E-Print Network [OSTI]

    Demko, Jonathan Alexander

    2012-06-07T23:59:59.000Z

    UC (I ~ M) ?0 e DO VC {I, N) ?O. DO UH(I, l)=0 DO VH (I, 1) ?O. DO ALONG FLUID CENTERLINE DO 6 I?1, N FOR VOBTICITY AMD STREAM WH(I, M) =0 ODO WC (I ~ 'l) =Do ODD PSIC(I ~ 1) =le ODO-RD PSIH fI, N) 1. ODO-BD CENTERLINE VALOIS FOB TH...-VELOCITY HOT' CALL POUT (VH r NrN) WRITE (6, 80) PRINT ~ HOT ILUID TEHPZRATURE ~ CALL POUT, {TH ~ N, N) llRITE (6 ~ 80) IF (IPLAG ZO. 1) GO TO 37 37 43 712 PRINTi o SOLID TEMPERATURE ~ CALL POUT (TS, H, 1) GO TO 42 WRITE (6 ~ 43) FORMAT(/, 20X, i...

  1. Testing thermocline filler materials and molten-salt heat transfer fluids for thermal energy storage systems used in parabolic trough solar power plants.

    SciTech Connect (OSTI)

    Kelly, Michael James; Hlava, Paul Frank; Brosseau, Douglas A.

    2004-07-01T23:59:59.000Z

    Parabolic trough power systems that utilize concentrated solar energy to generate electricity are a proven technology. Industry and laboratory research efforts are now focusing on integration of thermal energy storage as a viable means to enhance dispatchability of concentrated solar energy. One option to significantly reduce costs is to use thermocline storage systems, low-cost filler materials as the primary thermal storage medium, and molten nitrate salts as the direct heat transfer fluid. Prior thermocline evaluations and thermal cycling tests at the Sandia National Laboratories' National Solar Thermal Test Facility identified quartzite rock and silica sand as potential filler materials. An expanded series of isothermal and thermal cycling experiments were planned and implemented to extend those studies in order to demonstrate the durability of these filler materials in molten nitrate salts over a range of operating temperatures for extended timeframes. Upon test completion, careful analyses of filler material samples, as well as the molten salt, were conducted to assess long-term durability and degradation mechanisms in these test conditions. Analysis results demonstrate that the quartzite rock and silica sand appear able to withstand the molten salt environment quite well. No significant deterioration that would impact the performance or operability of a thermocline thermal energy storage system was evident. Therefore, additional studies of the thermocline concept can continue armed with confidence that appropriate filler materials have been identified for the intended application.

  2. ANALYTIC CRITERIA FOR THE MECHANICAL AND THERMAL STABILITY OF MAGNETIC STARS WITH FINITE ELECTRICAL CONDUCTIVITY

    E-Print Network [OSTI]

    ANALYTIC CRITERIA FOR THE MECHANICAL AND THERMAL STABILITY OF MAGNETIC STARS WITH FINITE ELECTRICAL in the envelope. This physical complication also affects the interpretation of the RR Lyrae stars and other cool stars, the destabilized envelope is mostly radiative and convection probably plays only a small role

  3. Electrical and Thermal Conductivity of Ge/Si Quantum Dot Superlattices

    E-Print Network [OSTI]

    . Good carrier mobility and electric con- ductivity are important for thermoelectric materials where-Riverside, Riverside, California 92521, USA Recently proposed thermoelectric applications of quantum dot superlattices made of different material systems depend crucially on the values of the electrical and thermal

  4. RODCON: a finite difference heat conduction computer code in cylindrical coordinates

    SciTech Connect (OSTI)

    Conklin, J.C.

    1980-09-16T23:59:59.000Z

    RODCON, a finite difference computer code, was developed to calculate the internal temperature distribution of the fuel rod simulator (FRS) for the Core Flow Test Loop (CFTL). RODCON solves the implicit, time-dependent forward-differencing heat transfer equation in 2-dimensional (Rtheta) cylindrical coordinates at an axial plane with user specified radial material zones and surface conditions at the FRS periphery. Symmetry of the boundary conditions of coolant bulk temperatures and film coefficients at the FRS periphery is not necessary.

  5. Modelling Heat Transfer of Carbon Nanotubes

    E-Print Network [OSTI]

    Yang, Xin-She

    2010-01-01T23:59:59.000Z

    Modelling heat transfer of carbon nanotubes is important for the thermal management of nanotube-based composites and nanoelectronic device. By using a finite element method for three-dimensional anisotropic heat transfer, we have simulated the heat conduction and temperature variations of a single nanotube, a nanotube array and a part of nanotube-based composite surface with heat generation. The thermal conductivity used is obtained from the upscaled value from the molecular simulations or experiments. Simulations show that nanotube arrays have unique cooling characteristics due to its anisotropic thermal conductivity.

  6. Electron heat conduction under non-Maxwellian distribution in hohlraum simulation

    SciTech Connect (OSTI)

    Wen Yihuo; Ke Lan; Pei Jungu; Heng Yong; Qing Hongzeng [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2012-01-15T23:59:59.000Z

    An electron transport model based on the non-Maxwellian distribution f{sub 0}{proportional_to}e{sup -{nu}{sup m}} (NM model), caused by the inverse bremsstrahlung heating, is used in 1-D plane target and 2-D hohlraum simulations. In the NM model, the electron heat flux depends not only on the gradient of electron temperature T{sub e} but also on the gradients of electron number density and the index m. From 1-D simulations, the spatial distribution of T{sub e} is dune-like and T{sub e} decreases obviously in the flux-heated region, which is very different from the flat profile obtained by using the flux limit model (FL model) but similar to the experimental observations [Gregori et al., Phys. Rev. Lett. 92, 205006 (2004)] and the nonlocal results [Rosen et al., High Energy Density Phys. 7, 180 (2011)]. The reason which causes the dune-like profile of T{sub e} is discussed in the paper. From 2-D hohlraum simulations, the NM results of the plasma status, the emission peak and profile inside hohlraum are very different from the FL model results. Finally, it is hard to use an average flux limiter in the FL model to obtain the same hohlraum plasma status and emission with those under the NM model.

  7. Full-scale study of a building equipped with phase change material wallboards and a multi-layer rack latent heat thermal energy store system

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    -layer rack latent heat thermal energy store system Julien Borderon1 , Joseph Virgone2 , Richard Cantin1 installed as wallboard and as latent heat thermal energy storage system coupled with the ventilation system for the ventilation air is efficient. INTRODUCTION Nowadays, thermal energy storage systems are one way for reducing

  8. Thermal History of the Felsite Unit, Geysers Geothermal Field, From Thermal Modeling of 40Ar/39Ar Incremental Heating Data

    SciTech Connect (OSTI)

    T. M. Harrison (U of California); G. B. Dalrymple (Oregon State U); J. B. Hulen (U of Utah); M. A. Lanphere; M. Grove; O. M. Lovera

    1999-08-19T23:59:59.000Z

    An Ar-40/Ar-39 and U-Pb study was performed of the Geysers plutonic complex of the Geysers Geothermal Field in California. Sixty-nine ion microprobe spot analyses of zircons from four granite samples from the plutonic complex that underlies the Geysers geothermal field yielded Pb-207/Pb-206 vs. U-238/Pb-206 concordia ages ranging from 1.13 {+-} 0.04 Ma to 1.25 {+-} 0.04 Ma. The U-Pb ages coincide closely with Ar-40/Ar-39 age spectrum plateau and ''terminal'' ages from coexisting K-feldspars and with the eruption ages of overlying volcanic rocks. The data indicate that the granite crystallized at 1.18 Ma and had cooled below 350 C by {approximately}0.9-1.0 Ma. Interpretation of the feldspar Ar-40/Ar-39 age data using multi-diffusion domain theory indicates that post-emplacement rapid cooling was succeeded either by slower cooling from 350-300 C between 1.0 and 0.4 Ma or transitory reheating to 300-350 C at about 0.4-0.6 Ma. Heat flow calculations constrained with K-feldspar thermal histories and the pre sent elevated regional heal flow anomaly demonstrate that appreciable heat input from sources external to the known Geysers plutonic complex is required to maintain the geothermal system. This requirement is satisfied by either a large, underlying, convecting magma chamber (now solidified) emplaced at 1.2 Ma or episodic intrusion of smaller bodies from 1.2-0.6 Ma.

  9. A quasi-3D analysis of the thermal performance of a flat heat pipe G. Carbajal a,*, C.B. Sobhan b

    E-Print Network [OSTI]

    Wadley, Haydn

    A quasi-3D analysis of the thermal performance of a flat heat pipe G. Carbajal a,*, C.B. Sobhan b form 29 January 2007 Available online 8 May 2007 Abstract The thermal performance of a flat heat pipe. The transient temperature distribution on a solid aluminum plate was compared with the flat heat pipe results

  10. Spring 2014 Heat Transfer -1

    E-Print Network [OSTI]

    Virginia Tech

    Spring 2014 1 Heat Transfer - 1 Consider a cylindrical nuclear fuel rod of length L and diameter df and the tube at a rate m , and the outer surface of the tube is well insulated. Heat generation occurs within. The specific heat of water pc , and the thermal conductivity of the fuel rod fk are constants. The system

  11. Heat distribution ceramic processing method

    DOE Patents [OSTI]

    Tiegs, Terry N. (Lenoir City, TN); Kiggans, Jr., James O. (Oak Ridge, TN)

    2001-01-01T23:59:59.000Z

    A multi-layered heat distributor system is provided for use in a microwave process. The multi-layered heat distributors includes a first inner layer of a high thermal conductivity heat distributor material, a middle insulating layer and an optional third insulating outer layer. The multi-layered heat distributor system is placed around the ceramic composition or article to be processed and located in a microwave heating system. Sufficient microwave energy is applied to provide a high density, unflawed ceramic product.

  12. Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools

    E-Print Network [OSTI]

    Transfer Design Tools Arild Gustavsen1,* , Dariush Arasteh2 , Bjørn Petter Jelle3,4 , Charlie Curcija5-conductance window frames requires accurate simulation tools for product research and development. Based and develop recommendation for inclusion into the design fenestration tools. 3. Assess existing correlations

  13. Thermal conductivity of Er{sup +3}:Y{sub 2}O{sub 3} films grown by atomic layer deposition

    SciTech Connect (OSTI)

    Raeisi Fard, Hafez; Hess, Andrew; Pashayi, Kamyar; Borca-Tasciuc, Theodorian, E-mail: borcat@rpi.edu [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Mechanical, Aerospace and Nuclear Engineering Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Becker, Nicholas; Proslier, Thomas; Pellin, Michael [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)] [Material Sciences Division, Argonne National Laboratory 9700 S. Cass Avenue, Lemont, Illinois 60439 (United States)

    2013-11-04T23:59:59.000Z

    Cross-plane thermal conductivity of 800, 458, and 110?nm erbium-doped crystalline yttria (Er{sup +3}:Y{sub 2}O{sub 3}) films deposited via atomic layer deposition was measured using the 3? method at room temperature. Thermal conductivity results show 16-fold increase in thermal conductivity from 0.49?W m{sup ?1}K{sup ?1} to 8?W m{sup ?1}K{sup ?1} upon post deposition annealing, partially due to the suppression of the number of the -OH/H{sub 2}O bonds in the films after annealing. Thermal conductivity of the annealed film was ?70% lower than undoped bulk single crystal yttria. The cumulative interface thermal resistivity of substrate-Er{sup +3}:Y{sub 2}O{sub 3}-metal heater was determined to be ?2.5?×?10{sup ?8} m{sup 2} K/W.

  14. Control of differential strain during heating and cooling of mixed conducting metal oxide membranes

    DOE Patents [OSTI]

    Carolan, Michael Francis (Allentown, PA)

    2007-12-25T23:59:59.000Z

    Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side and a permeate side, which method comprises controlling the differential strain between the oxidant feed side and the permeate side by varying either or both of the oxygen partial pressure and the total gas pressure on either or both of the oxidant feed side and the permeate side of the membrane while changing the temperature of the membrane from a first temperature to a second temperature.

  15. Thermal conductance of the junction between single-walled carbon nanotubes

    E-Print Network [OSTI]

    McGaughey, Alan

    conductances of the carbon nanotube (CNT) junctions that would be found in a CNT aerogel are predicted using of carbon nanotubes (CNTs) (e.g., aligned films, mats, and aerogels) are candidates for use in electronic issue in all of these applications. Our focus here is related to single-walled CNT aerogels, which

  16. Role of Nanostructures in Reducing Thermal Conductivity below Alloy Limit in Crystalline Solids

    E-Print Network [OSTI]

    reduce electrical conductivity, making it ineffective for increasing the material's thermoelectric figure conversion devices depends on the thermoelectric figure of merit (ZT) of a material, which is defined as ZT thermoelectric materials [3-5]. While the original goal for nanostructuring was to increase S2 due to quantum

  17. Scaling laws for thermal conductivity of crystalline nanoporous silicon based on molecular dynamics simulations

    E-Print Network [OSTI]

    Pilon, Laurent

    is a potentially efficient ther- moelectric material for energy harvesting applications.11,12 Thermoelectric on the temperature and on the material.13 Good thermoelectric materials feature high electrical conductivity and high to the interdependence among r, S, and k.13 As a thermoelectric material, bulk dense crystalline Si is considered

  18. An experimental measurement of the thermal conductivity and diffusivity of a porous solid-liquid system

    E-Print Network [OSTI]

    Dunn, James Elliott

    1959-01-01T23:59:59.000Z

    to contain the sample for the flow rate measurement. 1. Air Supply 2 ~ Vacuun Line 3. Waste Line 4 ~ Surge Tank 5. Water Reservoir 6. Oil Reservoir Test Specinsn 8. Pressure Regulator Valve SATURATION APPARATUS FCR SATURATI?l SARDSTONR TXSP... the system can be described by' the one h dimensional form of Fouriers dT Equation: Q ~ -!:. A ? . ds The quantity of heat flowing through the oil and water in the pore dT space is OCk! ~ K A& ( ? ) + Kp AC (~)C ~ Based on the unidirectional W & d...

  19. An apparatus for the measurement of thermal conductivity of liquid neon

    E-Print Network [OSTI]

    Jensen, Jerald Norman

    1967-01-01T23:59:59.000Z

    past the max1mum recommended storage temperature of 100 C. The hot plate, Pl, and guard ring, P2, are heated. by nicrome heater wires, whose respective resistances are 50 ohms and. 150 ohms. An additional heater of 5 ohms was placed near the cupro-nickel.... to the heater. They were coiled around the top of the guard. ring once before being soldered to the number 36 copper wires leading to the top plate. The number 36 wires go to the top plate by means of a 1/8 in. cupro-nickel tube and were sealed from...

  20. Midtemperature Solar Systems Test Facility predictions for thermal performance of the Suntec solar collector with heat-formed glass reflector surface

    SciTech Connect (OSTI)

    Harrison, T.D.

    1980-11-01T23:59:59.000Z

    Thermal performance predictions are presented for the Suntec solar collector, with heat-formed glass reflector surface, for three output temperatures at five cities in the United States.

  1. PWR blowdown heat transfer separate-effects program - Thermal-Hydraulic Test Facility experimental data report for test 177. [Contains microfiche data

    SciTech Connect (OSTI)

    Clemons, V.D.; Flanders, R.M.; Craddick, W.G.

    1980-08-01T23:59:59.000Z

    Reduced instrument responses are presented for Thermal-Hydraulic Test Facility (THTF) test 177, which is part of the ORNL Pressurized-Water Reactor (PWR) Blowdown Heat Transfer Separate-Effects Program. Objective of the program is to investigate the thermal-hydraulic phenomenon governing the energy transfer and transport processes that occur during a loss-of-coolant accident in a PWR system. Test 177 was conducted at the request of Idaho National Engineering Laboratory ''for use in the independent assessment of RELAP4/MOD6.'' Primary purpose of this report is to make the reduced instrument responses during test 177 available. The responses are presented in graphical form in engineering units and have been analyzed only to the extent necessary to assure reasonableness and consistency. The data are presented in microfiche form.

  2. Investigation of the thermal conductivity of unconsolidated sand packs containing oil, water, and gas

    E-Print Network [OSTI]

    Gore, David Eugene

    2012-06-07T23:59:59.000Z

    INVESTIGATION OF THE THERNAL CONDUCTIVITY OF UNCONSOLIDATED SAND PACKS CONTAINING OIL, WATER, AND GAS A Thesis David E. Gore Submitted to the Graduate School of the Agricultural and Nechanical College oi' Texas in Partial fulfillment.... EXPERIMENTAL EQUIPMENT AND PROCEDURE All tests were performed on unconsolidated sand packs containing either one, two, or three saturating fluids, Phys- ical properties of the sand and saturating fluids are shown in Tables I and II in the Appendix...

  3. Electrical conductivity and charge diffusion in thermal QCD from the lattice

    E-Print Network [OSTI]

    Gert Aarts; Chris Allton; Alessandro Amato; Pietro Giudice; Simon Hands; Jon-Ivar Skullerud

    2015-02-12T23:59:59.000Z

    We present a lattice QCD calculation of the charge diffusion coefficient, the electrical conductivity and various susceptibilities of conserved charges, for a range of temperatures below and above the deconfinement crossover. The calculations include the contributions from up, down and strange quarks. We find that the diffusion coefficient is of the order of 1/(2\\pi T) and has a dip around the crossover temperature. Our results are obtained with lattice simulations containing 2+1 dynamical flavours on anisotropic lattices. The Maximum Entropy Method is used to construct spectral functions from correlators of the conserved vector current.

  4. Thermal Conductivity Measurement of Xe-Implanted Uranium Dioxide Thick Films using Multilayer Laser Flash Analysis

    SciTech Connect (OSTI)

    Nelson, Andrew T. [Los Alamos National Laboratory

    2012-08-30T23:59:59.000Z

    The Fuel Cycle Research and Development program's Advanced Fuels campaign is currently pursuing use of ion beam assisted deposition to produce uranium dioxide thick films containing xenon in various morphologies. To date, this technique has provided materials of interest for validation of predictive fuel performance codes and to provide insight into the behavior of xenon and other fission gasses under extreme conditions. In addition to the structural data provided by such thick films, it may be possible to couple these materials with multilayer laser flash analysis in order to measure the impact of xenon on thermal transport in uranium dioxide. A number of substrate materials (single crystal silicon carbide, molybdenum, and quartz) containing uranium dioxide films ranging from one to eight microns in thickness were evaluated using multilayer laser flash analysis in order to provide recommendations on the most promising substrates and geometries for further investigation. In general, the uranium dioxide films grown to date using ion beam assisted deposition were all found too thin for accurate measurement. Of the substrates tested, molybdenum performed the best and looks to be the best candidate for further development. Results obtained within this study suggest that the technique does possess the necessary resolution for measurement of uranium dioxide thick films, provided the films are grown in excess of fifty microns. This requirement is congruent with the material needs when viewed from a fundamental standpoint, as this length scale of material is required to adequately sample grain boundaries and possible second phases present in ceramic nuclear fuel.

  5. Conduction cooled tube supports

    DOE Patents [OSTI]

    Worley, Arthur C. (Mt. Tabor, NJ); Becht, IV, Charles (Morristown, NJ)

    1984-01-01T23:59:59.000Z

    In boilers, process tubes are suspended by means of support studs that are in thermal contact with and attached to the metal roof casing of the boiler and the upper bend portions of the process tubes. The support studs are sufficiently short that when the boiler is in use, the support studs are cooled by conduction of heat to the process tubes and the roof casing thereby maintaining the temperature of the stud so that it does not exceed 1400.degree. F.

  6. Thermal storage studies for solar heating and cooling: applications using chemical heat pumps. Final report, September 15, 1979-April 15, 1980

    SciTech Connect (OSTI)

    Offenhartz, P O.D.

    1981-04-01T23:59:59.000Z

    TRNSYS-compatible subroutines for the simulation of chemical heat pumps have been written, and simulations (including heating, cooling, and domestic hot water) have been performed for Washington, DC and Ft. Worth, Texas. Direct weekly comparisons of the H/sub 2/SO/sub 4//H/sub 2/O and CaCl/sub 2//CH/sub 3/OH cycles have been carried out. Projected performance of the NH/sub 4/NO/sub 3//NH/sub 3/ cycle has also been investigated, and found to be essentially identical to H/sub 2/SO/sub 4//H/sub 2/O. In all cases simulated, the solar collector is a fixed evacuated tube system, which is necessary because chemical heat pumps operate at higher solar collector temperatures (> 100/sup 0/C) than conventional solar systems. With standard residential loads, the chemical heat pumps performed surprisingly well. In the Ft. Worth climate, less than 45 m/sup 2/ of collectors were required to meet over 90% of the heating and cooling loads. In Washington, DC, the area required to meet the cooling load was smaller (as little as 20 m/sup 2/, depending on window shading), but was sufficient to meet only 50 to 60% of the heating load. However, gas-fired backup via the heat pump was quite effective in reducing fossil fuel consumption: the thermal COPs in the heating mode were in the range 1.6 to 1.7. Since chemical heat pumps are designed to reject heat at relatively high temperatures, they were also effective in providing domestic hot water, supplying ca. 70% of the DHW in summer, ca. 50% in winter, and nearly 100% in spring and fall.

  7. Thermal Management of Solar Cells

    E-Print Network [OSTI]

    Saadah, Mohammed Ahmed

    2013-01-01T23:59:59.000Z

    a better thermal conductance and when ceramic particles areor ceramic fillers that enhances thermal conductivity. Solid

  8. Enhancement of specific heat capacity of high-temperature silica-nanofluids synthesized in alkali chloride salt eutectics for solar thermal-energy

    E-Print Network [OSTI]

    Banerjee, Debjyoti

    chloride salt eutectics for solar thermal-energy storage applications Donghyun Shin, Debjyoti Banerjee for the anoma- lous enhancement of thermal conductivity over that of the neat solvent. Eastman et al. [5] reported thermal conductivity enhance- ment of 30% and 60% for water based nanofluids of Al2O3 and Cu

  9. A semi-analytical model for heat and mass transfer in geothermal reservoirs to estimate fracture surface-are-to-volume ratios and thermal breakthrough using thermally-decaying and diffusing tracers

    SciTech Connect (OSTI)

    Reimus, Paul W [Los Alamos National Laboratory

    2010-12-08T23:59:59.000Z

    A semi-analytical model was developed to conduct rapid scoping calculations of responses of thermally degrading and diffusing tracers in multi-well tracer tests in enhanced geothermal systems (EGS). The model is based on an existing Laplace transform inversion model for solute transport in dual-porosity media. The heat- and mass-transfer calculations are decoupled and conducted sequentially, taking advantage of the fact that heat transfer between fractures and the rock matrix is much more rapid than mass transfer and therefore mass transfer will effectively occur in a locally isothermal system (although the system will be nonisothermal along fracture flow pathways, which is accounted for by discretizing the flow pathways into multiple segments that have different temperature histories). The model takes advantage of the analogies between heat and mass transfer, solving the same governing equations with k{sub m}/({rho}C{sub p}){sub w} being substituted for {phi}D{sub m} in the equation for fracture transport and k{sub m}/({rho}C{sub p}){sub m} being subsituted for D{sub m} in the equation for matrix transport; where k = thermal conductivity (cal/cm-s-K), {rho} = density (g/cm{sup 3}), C{sub p} = heat capacity (at constant pressure) (cal/g-K), {phi} = matrix porosity, and D = tracer diffusion coefficient (cm{sup 2}/s), with the subscripts w and m referring to water and matrix, respectively. A significant advantage of the model is that it executes in a fraction of second on a single-CPU personal computer, making it very amenable for parameter estimation algorithms that involve repeated runs to find global minima. The combined thermal-mass transport model was used to evaluate the ability to estimate when thermal breakthrough would occur in a multi-well EGS configuration using thermally degrading tracers. Calculations were conducted to evaluate the range of values of Arrhenius parameters, A and E{sub {alpha}} (pre-exponential factor, 1/s, and activation energy, cal/mol) required to obtain interpretable responses of thermally-degrading tracers that decay according to the rate constant k{sub d} = Ae{sup -E{sub {alpha}}/RT}, where k{sub d} = decay rate constant (1/s), R = ideal gas constant (1.987 cal/mol-K), and T = absolute temperature (K). It is shown that there are relatively narrow ranges of A and E{sub {alpha}} that will result in readily interpretable tracer responses for any given combination of ambient reservoir temperature and working fluid residence time in a reservoir. The combined model was also used to simulate the responses of conservative tracers with different diffusion coefficients as a way of estimating fracture surface-area-to-volume ratios (SA/V) in multi-well EGS systems. This method takes advantage of the fact that the differences in breakthrough curves of tracers with different matrix diffusion coefficients are a function of SA/V. The model accounts for differences in diffusion coefficients as a function of temperature so that tracer responses obtained at different times can be used to obtain consistent estimates of SA/V as the reservoir cools down. Some single-well applications of this approach are simulated with a numerical model to demonstrate the potential to evaluate the effectiveness of EGS stimulations before a second well is drilled.

  10. A NEW SOLAR THERMAL RECEIVER UTILIZING A SMALL PARTICLE HEAT EXCHANGER

    E-Print Network [OSTI]

    Hunt, Arlon J.

    2011-01-01T23:59:59.000Z

    Report LBL 8520. ) A NEW SOLAR THERMAL RECEIVER UTILIZING Aenergy. A new type of solar thermal receiver based on thisThe success of the solar thermal electric power program

  11. Method and apparatus for thermal management of vehicle exhaust systems

    DOE Patents [OSTI]

    Benson, David K. (Golden, CO); Potter, Thomas F. (Denver, CO)

    1995-01-01T23:59:59.000Z

    A catalytic converter is surrounded by variable conductance insulation for maintaining the operating temperature of the catalytic converter at an optimum level, for inhibiting heat loss when raising catalytic converter temperature to light-off temperature, for storing excess heat to maintain or accelerate reaching light-off temperature, and for conducting excess heat away from the catalytic converter after reaching light-off temperature. The variable conductance insulation includes vacuum gas control and metal-to-metal thermal shunt mechanisms. Radial and axial shielding inhibits radiation and convection heat loss. Thermal storage media includes phase change material, and heat exchanger chambers and fluids carry heat to and from the catalytic converter.

  12. Exploration of coal-based pitch precursors for ultra-high thermal conductivity graphite fibers. Final report

    SciTech Connect (OSTI)

    Deshpande, G.V. [Amoco Performance Products, Inc., Alpharetta, GA (United States)

    1996-12-27T23:59:59.000Z

    Goal was to explore the utility of coal-based pitch precursors for use in ultra high thermal conductivity carbon (graphite) fibers. From graphite electrode experience, it was established that coal-based pitches tend to form more highly crystalline graphite at lower temperatures. Since the funding was limited to year 1 effort of the 3 year program, the goal was only partially achieved. The coal-base pitches can form large domain mesophase in spite of high N and O contents. The mesophase reactivity test performed on one of the variants of coal-based pitch (DO84) showed that it was not a good candidate for carbon fiber processing. Optimization of WVU`s isotropic pitch process is required to tailor the pitch for carbon fiber processing. The hetero atoms in the coal pitch need to be reduced to improve mesophase formation.

  13. E-Print Network 3.0 - advanced thermally stable Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plaza, Gold Coast, Australia Summary: Abstract The development of advanced heat transfer fluids with enhanced thermal conductivity is essential... The Importance of Suspension...

  14. Experimental Investigation on Thermal Properties of a Steel-jacketed Steam Heating Pipeline with Vacuum Insulation

    E-Print Network [OSTI]

    Na, W.; Zou, P.

    2006-01-01T23:59:59.000Z

    The steel-jacketed steam heating pipeline employs vacuum insulation to improve the insulating effect and reduce the corrosion, and hence increases the heat transfer efficiency of the heating network and building energy efficiency. It is important...

  15. Thermal Performance of Microencapsulated Phase Material (MPCM) Slurry in a Coaxial Heat Exchanger

    E-Print Network [OSTI]

    Yu, Kun

    2014-05-08T23:59:59.000Z

    Microencapsulated phase change material (MPCM) slurries and coil heat exchangers had been recently studied separately as enhancers of convective heat transfer processes. Due to the larger apparent heat related to the phase change process...

  16. Thermal conductivity of large-grain niobium and its effect on trapped vortices in the temperature range 1.8?5 K

    SciTech Connect (OSTI)

    Mondal, Jayanta [Bhabha Atomic Research Centre; Ciovati, Gianluigi [JLAB; Mittal, Kailash C. [Bhabha Atomic Research Centre; Myneni, Ganapati Rao [JLAB

    2012-04-01T23:59:59.000Z

    Experimental investigation of the thermal conductivity of large grain and its dependence on the trapped vortices in parallel magnetic field with respect to the temperature gradient {gradient}T was carried out on four large-grain niobium samples from four different ingots. The zero-field thermal conductivity measurements are in good agreement with the measurements based on the theory of Bardeen-Rickayzen-Tewordt (BRT). The change in thermal conductivity with trapped vortices is analysed with the field dependence of the conductivity results of Vinen et al for low inductions and low-temperature situation. Finally, the dependence of thermal conductivity on the applied magnetic field in the vicinity of the upper critical field H{sub c2} is fitted with the theory of pure type-II superconductor of Houghton and Maki. Initial remnant magnetization in the sample shows a departure from the Houghton?Maki curve whereas the sample with zero trapped flux qualitatively agrees with the theory. A qualitative discussion is presented explaining the reason for such deviation from the theory. It has also been observed that if the sample with the trapped vortices is cycled through T{sub c}, the subsequent measurement of the thermal conductivity coincides with the zero trapped flux results.

  17. Smoothing HCCI heat release with vaporization-cooling-induced thermal stratification using ethanol.

    SciTech Connect (OSTI)

    Dec, John E.; Sjoberg, Carl-Magnus G.

    2010-12-01T23:59:59.000Z

    Ethanol and ethanol/gasoline blends are being widely considered as alternative fuels for light-duty automotive applications. At the same time, HCCI combustion has the potential to provide high efficiency and ultra-low exhaust emissions. However, the application of HCCI is typically limited to low and moderate loads because of unacceptably high heat-release rates (HRR) at higher fueling rates. This work investigates the potential of lowering the HCCI HRR at high loads by using partial fuel stratification to increase the in-cylinder thermal stratification. This strategy is based on ethanol's high heat of vaporization combined with its true single-stage ignition characteristics. Using partial fuel stratification, the strong fuel-vaporization cooling produces thermal stratification due to variations in the amount of fuel vaporization in different parts of the combustion chamber. The low sensitivity of the autoignition reactions to variations of the local fuel concentration allows the temperature variations to govern the combustion event. This results in a sequential autoignition event from leaner and hotter zones to richer and colder zones, lowering the overall combustion rate compared to operation with a uniform fuel/air mixture. The amount of partial fuel stratification was varied by adjusting the fraction of fuel injected late to produce stratification, and also by changing the timing of the late injection. The experiments show that a combination of 60-70% premixed charge and injection of 30-40 % of the fuel at 80{sup o}CA before TDC is effective for smoothing the HRR. With CA50 held fixed, this increases the burn duration by 55% and reduces the maximum pressure-rise rate by 40%. Combustion stability remains high but engine-out NO{sub x} has to be monitored carefully. For operation with strong reduction of the peak HRR, ISNO{sub x} rises to around 0.20 g/kWh for an IMEP{sub g} of 440 kPa. The single-cylinder HCCI research engine was operated naturally aspirated without EGR at 1200 rpm, and had low residual level using a CR = 14 piston.

  18. Estimation of Biomass Heat Storage Using Thermal Infrared Imagery: Application to a Walnut Orchard

    E-Print Network [OSTI]

    Garai, Anirban; Kleissl, Jan; Llewellyn Smith, Stefan G.

    2010-01-01T23:59:59.000Z

    NOTE Estimation of Biomass Heat Storage Using Thermalmethod to estimate tree biomass heat storage from thermalinfrared (TIR) imaging of biomass surface temperature is

  19. 7-122 A solar pond power plant operates by absorbing heat from the hot region near the bottom, and rejecting waste heat to the cold region near the top. The maximum thermal efficiency that the power plant

    E-Print Network [OSTI]

    Bahrami, Majid

    calculated above. 7-123 A Carnot heat engine cycle is executed in a closed system with a fixed mass of steam can have is to be determined. Analysis The highest thermal efficiency a heat engine operating between transfer. Therefore, the maximum efficiency of the actual heat engine will be lower than the value

  20. Abstract --The beneficial effect of AlN heat spreaders in terms of reduction of thermal resistance is tested on silicon-on-

    E-Print Network [OSTI]

    Technische Universiteit Delft

    Abstract -- The beneficial effect of AlN heat spreaders in terms of reduction of thermal resistance such as SiO2 and SiNx can also lead to a very high thermal resistance. This has been demonstrated it is shown that PVD AlN layers result in a significant reduction of thermal resistance in a single device