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Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
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1

Modeling of Heat Transfer in Geothermal Heat Exchangers  

E-Print Network (OSTI)

Ground-coupled heat pump (GCHP) systems have been gaining increasing popularity for space conditioning in residential and commercial buildings. The geothermal heat exchanger (GHE) is devised for extraction or injection of thermal energy from/into the ground. This paper summarizes the authors' studies on heat transfer in ground-coupled heat pump systems. Taking the fluid axial convective heat transfer and thermal “short-circuiting” among U-tube legs into account, a quasi-3-D model has been solved for heat transfer inside boreholes. The transient 2-D temperature response in a semi-infinite medium with a line-source of finite length has also been derived for heat conduction outside boreholes. In order to investigate the impact of groundwater advection on the performance of ground heat exchangers, an analytical solution is obtained for a line heat source in an infinite porous medium with groundwater advection. These explicit expressions have more solid theoretical basis, and can be easily incorporated into computer programs for thermal analysis and engineering design of ground heat exchangers.

Cui, P.; Man, Y.; Fang, Z.

2006-01-01T23:59:59.000Z

2

NISTIR 6299 A Heat Transfer Model for Fire Fighter's ...  

Science Conference Proceedings (OSTI)

Page 1. NISTIR 6299 A Heat Transfer Model for Fire Fighter's Protective Clothing William E. Mell J. Randall Lawson United ...

1999-05-06T23:59:59.000Z

3

CFD Modelling of Heat Transfer in Supersonic Nozzles for ... - TMS  

Science Conference Proceedings (OSTI)

May 1, 2007 ... CFD Modelling of Heat Transfer in Supersonic Nozzles for Magnesium Production by Peter Witt, M.N.H. Khan, and Geoffrey Brooks ...

4

MODELING OF HEAT TRANSFER IN ROOMS IN THE MODELICA  

NLE Websites -- All DOE Office Websites (Extended Search)

MODELING MODELING OF HEAT TRANSFER IN ROOMS IN THE MODELICA "BUILDINGS" LIBRARY Michael Wetter, Wangda Zuo, Thierry Stephane Nouidui Simulation Research Group, Building Technologies Department Environmental Energy Technologies Division, Lawrence Berkeley National Laboratory Berkeley, CA 94720, USA ABSTRACT This paper describes the implementation of the room heat transfer model in the free open-source Modelica "Buildings" library. The model can be used as a single room or to compose a multizone building model. We discuss how the model is de- composed into submodels for the individual heat transfer phenomena. We also discuss the main physical assumptions. The room model can be parameterized to use di↵erent modeling assump- tions, leading to linear or non-linear di↵erential algebraic systems of equations. We present nu- merical experiments that show

5

Advanced Model and Methodology Development [Heat Transfer and Fluid  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Model and Advanced Model and Methodology Development Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Advanced Model and Methodology Development Electrorefiner Model for Treatment of Spent Nuclear Fuel Electrorefiner Model for Treatment of Spent Nuclear Fuel. Click on image to

6

Modeling of Heat Transfer in Rooms in the Modelica Buildings Library  

E-Print Network (OSTI)

for convective and radiative heat transfer yielded a twofoldModeling of Heat Transfer in Rooms in the Modelica “of California. MODELING OF HEAT TRANSFER IN ROOMS IN THE

Wetter, Michael

2013-01-01T23:59:59.000Z

7

THERM: Two-Dimensional Building Heat-Transfer Modeling  

NLE Websites -- All DOE Office Websites (Extended Search)

5 5 THERM: Two-Dimensional Building Heat-Transfer Modeling For more information and to download THERM, please visit our website: http://windows.lbl.gov/software/therm The Windows and Daylighting Group's two-year-old computer program THERM 1.0 is a state-of-the-art tool for modeling two-dimensional heat-transfer effects in building components. The thermal property information THERM provides is important for the design and application of building components such as windows, walls, foundations, roofs and doors. This Microsoft Windows-based program has great potential to users such as building component manufacturers, educators, students, architects, engineers and others who are interested in assessing the heat-transfer properties of single products, product interactions, or integrated systems. THERM

8

Thermodynamics of enhanced heat transfer: a model study  

E-Print Network (OSTI)

Situations where a spontaneous process of energy or matter transfer is enhanced by an external device are widespread in nature (human sweating system, enzyme catalysis, facilitated diffusion across bio-membranes, industrial heat exchangers). The thermodynamics of such processes remains however open. Here we study enhanced heat transfer by a model junction immersed between two thermal baths at different temperatures $T_h$ and $T_c$ ($T_h>T_c$). The transferred heat power is enhanced via controlling the junction by means of external time-dependent fields. Provided that the spontaneous heat flow process is optimized over the junction Hamiltonian, any enhancement of this spontaneous process does demand consumption and subsequent dissipation of work. The efficiency of enhancement is defined via the increment in the heat power divided over the amount of consumed work. We show that this efficiency is bounded from above by $T_c/(T_h-T_c)$. Formally this is identical to the Carnot bound for the efficiency of ordinary refrigerators which transfer heat from cold to hot. It also shares some (but not all) physical features of the Carnot bound.

Karen Hovhannisyan; Armen E. Allahverdyan

2010-07-20T23:59:59.000Z

9

Modelling Heat Transfer in Nanofluids Based on Coupled MD ...  

Science Conference Proceedings (OSTI)

Simulations have shown that the additional heat transfer caused by the collision of the nanoparticles with the heat source contributes significantly to the ...

10

Heat Transfer Modeling of Dry Spent Nuclear Fuel Storage Facilities  

Science Conference Proceedings (OSTI)

The present work was undertaken to provide heat transfer model that accurately predicts the thermal performance of dry spent nuclear fuel storage facilities. One of the storage configurations being considered for DOE Aluminum-clad Spent Nuclear Fuel (Al-SNF), such as the Material and Testing Reactor (MTR) fuel, is in a dry storage facility. To support design studies of storage options a computational and experimental program has been conducted at the Savannah River Site (SRS). The main objective is to develop heat transfer models including natural convection effects internal to an interim dry storage canister and to geological codisposal Waste Package (WP). Calculated temperatures will be used to demonstrate engineering viability of a dry storage option in enclosed interim storage and geological repository WP and to assess the chemical and physical behaviors of the Al-SNF in the dry storage facilities. The current paper describes the modeling approaches and presents the computational results along with the experimental data.

Lee, S.Y.

1999-01-13T23:59:59.000Z

11

Thermodynamics of enhanced heat transfer: a model study  

E-Print Network (OSTI)

Situations where a spontaneous process of energy or matter transfer is enhanced by an external device are widespread in nature (human sweating system, enzyme catalysis, facilitated diffusion across bio-membranes, industrial heat exchangers). The thermodynamics of such processes remains however open. Here we study enhanced heat transfer by a model junction immersed between two thermal baths at different temperatures $T_h$ and $T_c$ ($T_h>T_c$). The transferred heat power is enhanced via controlling the junction by means of external time-dependent fields. Provided that the spontaneous heat flow process is optimized over the junction Hamiltonian, any enhancement of this spontaneous process does demand consumption and subsequent dissipation of work. The efficiency of enhancement is defined via the increment in the heat power divided over the amount of consumed work. We show that this efficiency is bounded from above by $T_c/(T_h-T_c)$. Formally this is identical to the Carnot bound for the efficiency of ordinary ...

Hovhannisyan, Karen; 10.1088/1742-5468/2010/06/P06010

2010-01-01T23:59:59.000Z

12

Unified Model for the Heat Transfer Processes that Occur During  

E-Print Network (OSTI)

A unified general model for the heat transfer processes that occur within a food product subjected to canning or aseptic thermal treatment, is presented. Two principles are extensively used in the model building process: system segregation and energy balancing. The model is summarized in an algorithm, whose specification is showed for different combinations of processing system type (PST) and product formulation (PF) with a single particle type. A discussion on the practical relevance of proper product identification in the case of aseptic processing, is included. Finally, an illustration is given on the results that can be obtained from the model algorithm application, in a comparative study of different PST-PF combinations.

Jose F. Pastrana; Harvey J. Gold; Kenneth R. Swanzel; Pastrana Gold; Jose F. Pastrana; Harvey J. Gold; Kenneth R. Swartzel

1992-01-01T23:59:59.000Z

13

Convection Heat Transfer  

Science Conference Proceedings (OSTI)

...Heat-Transfer Equations, Fundamentals of Modeling for Metals Processing, Vol 22A, ASM Handbook, ASM International, 2009, p 625â??658...

14

RELAP5 MODEL OF THE DIVERTOR PRIMARY HEAT TRANSFER SYSTEM  

SciTech Connect

This report describes the RELAP5 model that has been developed for the divertor primary heat transfer system (PHTS). The model is intended to be used to examine the transient performance of the divertor PHTS and evaluate control schemes necessary to maintain parameters within acceptable limits during transients. Some preliminary results are presented to show the maturity of the model and examine general divertor PHTS transient behavior. The model can be used as a starting point for developing transient modeling capability, including control system modeling, safety evaluations, etc., and is not intended to represent the final divertor PHTS design. Preliminary calculations using the models indicate that during normal pulsed operation, present pressurizer controls may not be sufficient to keep system pressures within their desired range. Additional divertor PHTS and control system design efforts may be required to ensure system pressure fluctuation during normal operation remains within specified limits.

Popov, Emilian L [ORNL; Yoder Jr, Graydon L [ORNL; Kim, Seokho H [ORNL

2010-08-01T23:59:59.000Z

15

Development of a Heat Transfer Model for the Integrated Facade Heating  

E-Print Network (OSTI)

Façade heating is a special application of radiant heating and cooling technology and is used to enhance the indoor comfort level of offices, hotels and museums. Mullion radiators are typically used to implement façade heating. This paper analyzes the heat transfer process of facade heating (mullion radiators) in a pilot research project in Pittsburgh, PA. The heat transfer model for facade heating is developed and verified by measured data. The comparison shows that the heat transfer model predicts the measured temperatures with a root mean squared error (RMSE) of the hot water return temperature, the mullion surface temperature, and the window surface temperature of 0.90°F, 0.98°F and 1.15°F, respectively. The factors which affect the heating capacity of mullion radiators have been analyzed. The analysis shows that the supply water temperature is the primary factor which affects the heating or cooing capacity of window mullions and the mullion surface temperature. Return water temperature and mullion surface temperature are quasi-linear functions often water supply temperature. Mullion surface temperature, indoor air temperature gradient on the glazing surface within one foot from mullions is much higher than in the central part of the window. The temperatures in the central 2 feet of a 4-foot window show almost no influence by the mullion surface temperature. Also, the conductive thermal resistance of the mullion double tubes with fillings between two tubes plays a decisive role in controlling the mullion and window frame temperatures.

Gong, X.; Archer, D. H.; Claridge, D. E.

2007-01-01T23:59:59.000Z

16

Simulation of Static Flying Attitudes with Different Heat Transfer Models for a Flying-Height Control Slider with Thermal Protrusion  

E-Print Network (OSTI)

Zhang, S. , Bogy, D.B. : A heat transfer model for thermal ?A phenomenological heat transfer model for the molecular gasWong, C.H. : A generalized heat transfer model for thin ?lm

Chen, Du; Bogy, David B.

2010-01-01T23:59:59.000Z

17

Coupled Reactor Kinetics and Heat Transfer Model for Heat Pipe Cooled Reactors  

SciTech Connect

Heat pipes are often proposed as cooling system components for small fission reactors. SAFE-300 and STAR-C are two reactor concepts that use heat pipes as an integral part of the cooling system. Heat pipes have been used in reactors to cool components within radiation tests (Deverall, 1973); however, no reactor has been built or tested that uses heat pipes solely as the primary cooling system. Heat pipe cooled reactors will likely require the development of a test reactor to determine the main differences in operational behavior from forced cooled reactors. The purpose of this paper is to describe the results of a systems code capable of modeling the coupling between the reactor kinetics and heat pipe controlled heat transport. Heat transport in heat pipe reactors is complex and highly system dependent. Nevertheless, in general terms it relies on heat flowing from the fuel pins through the heat pipe, to the heat exchanger, and then ultimately into the power conversion system and heat sink. A system model is described that is capable of modeling coupled reactor kinetics phenomena, heat transfer dynamics within the fuel pins, and the transient behavior of heat pipes (including the melting of the working fluid). The paper focuses primarily on the coupling effects caused by reactor feedback and compares the observations with forced cooled reactors. A number of reactor startup transients have been modeled, and issues such as power peaking, and power-to-flow mismatches, and loading transients were examined, including the possibility of heat flow from the heat exchanger back into the reactor. This system model is envisioned as a tool to be used for screening various heat pipe cooled reactor concepts, for designing and developing test facility requirements, for use in safety evaluations, and for developing test criteria for in-pile and out-of-pile test facilities.

WRIGHT,STEVEN A.; HOUTS,MICHAEL

2000-11-22T23:59:59.000Z

18

Numerical heat transfer attic model using a radiant barrier system  

Science Conference Proceedings (OSTI)

A two-dimensional, steady-state finite-element model was developed to simulate the thermal effects of the application of an attic radiant barrier system (ARBS) inside a ventilated residential attic. The attic is ventilated using the exhaust air from an evaporative cooler. The study uses a {kappa}-{epsilon} turbulent model to describe the velocity and temperature distributions in the attic. The ambient temperature and solar isolation densities on the outside inclined attic surfaces are used as driving functions for the model. The model also included the appropriate heat exchange modes of convection and radiation on these outside surfaces. Several recirculation zones were visually observed in the attic flow pattern. Also, the use of the ARBS seems to lower the heat transfer through the ceiling by 25--30%, but this effect decreases significantly as the outside ventilation rates are increased through the attic space. The 2D model revealed some interesting temperature distributions along the attic surfaces that could not have been predicted by the one-dimensional models. The lower emissivity ARBS seems to raise the temperature of the inclined attic surfaces as well as the temperature of the exhausted ventilation air.

Moujaes, S.F.; Alsaiegh, N.T.

2000-04-01T23:59:59.000Z

19

MODELING HEAT TRANSFER IN SPENT FUEL TRANSFER CASK NEUTRON SHIELDS – A CHALLENGING PROBLEM IN NATURAL CONVECTION  

SciTech Connect

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 10-15 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper proposes that there may be reliable CFD approaches to the transfer cask problem, specifically coupled steady-state solvers or unsteady simulations; however, both of these solutions take significant computational effort. Segregated (uncoupled) steady state solvers that were tested did not accurately capture the flow field and heat transfer distribution in this application. Mesh resolution, turbulence modeling, and the tradeoff between steady state and transient solutions are addressed. Because of the critical nature of this application, the need for new experiments at representative scales is clearly demonstrated.

Fort, James A.; Cuta, Judith M.; Bajwa, C.; Baglietto, E.

2010-07-18T23:59:59.000Z

20

Modeling the Heating of Biological Tissue based on the Hyperbolic Heat Transfer Equation  

E-Print Network (OSTI)

In modern surgery, a multitude of minimally intrusive operational techniques are used which are based on the punctual heating of target zones of human tissue via laser or radio-frequency currents. Traditionally, these processes are modeled by the bioheat equation introduced by Pennes, who considers Fourier's theory of heat conduction. We present an alternative and more realistic model established by the hyperbolic equation of heat transfer. To demonstrate some features and advantages of our proposed method, we apply the obtained results to different types of tissue heating with high energy fluxes, in particular radiofrequency heating and pulsed laser treatment of the cornea to correct refractive errors. Hopefully, the results of our approach help to refine surgical interventions in this novel field of medical treatment.

Tung, M M; Molina, J A Lopez; Rivera, M J; Berjano, E J

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid3D Model of Heat Transfer and Fluid  

E-Print Network (OSTI)

Center for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat for Energy Efficiency and Renewable Energy at University of Massachusetts 3D Model of Heat Transfer and Fluid WindowModeling a 3D Window Future WorkFuture Work #12;Center for Energy Efficiency and Renewable Energy

Massachusetts at Amherst, University of

22

Application Of A Spherical-Radial Heat Transfer Model To Calculate...  

Open Energy Info (EERE)

Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal...

23

Modeling of Heat Transfer during Cooling of a Hot Steel Plate  

Science Conference Proceedings (OSTI)

Thus, it is crucial to develop accurate heat transfer models in order to predict the temperature history during cooling of steel plates. The present study describes a  ...

24

Heat Transfer Analysis and Modeling of a Parabolic Trough Solar Receiver Implemented in Engineering Equation Solver  

DOE Green Energy (OSTI)

This report describes the development, validation, and use of a heat transfer model implemented in Engineering Equation Solver. The model determines the performance of a parabolic trough solar collector's linear receiver, also called a heat collector element. All heat transfer and thermodynamic equations, optical properties, and parameters used in the model are discussed. The modeling assumptions and limitations are also discussed, along with recommendations for model improvement.

Forristall, R.

2003-10-01T23:59:59.000Z

25

Heat transfer research and power cycle transient modeling  

DOE Green Energy (OSTI)

Fine axial flutes enhance heat transfer in vertical shell-and-tube exchangers with water inside the tubes and ammonia evaporating or condensing in layer flow on the shell side. Single-tube experiments with R-11 and ammonia indicate local shell-side coefficients 3 to 5 times those for corresponding smooth tubes. Single-tube experiments with water indicate that at moderate velocities the tube-side coefficients are enhanced by a factor equal to the ratio of fluted-to-smooth surface areas while the fluid friction is similarly increased. The experimental data are transformed into mean individual coefficients for ammonia and water. Overall coefficients for a particular case are presented to illustrate the efficacy of enhancement by flutes on one or both sides of the heat transfer surface. Means are described for using emerging data to predict the static and dynamic behavior of the power cycle and the interactions of components throughout the complete power plant.

Rothfus, R.R.; Neuman, C.P.

1977-03-23T23:59:59.000Z

26

Modeling of Heat and Mass Transfer in Fusion Welding  

Science Conference Proceedings (OSTI)

In fusion welding, parts are joined together by melting and subsequent solidification. Although this principle is simple, complex transport phenomena take place during fusion welding, and they determine the final weld quality and performance. The heat and mass transfer in the weld pool directly affect the size and shape of the pool, the solidification microstructure, the formation of weld defects such as porosity and humping, and the temperature distribution in the fusion zone and heat-affected zone (HAZ). Furthermore, the temperature evolution affects the kinetics and extent of various solid-state phase transformations, which in turn determine the final weld microstructure and mechanical properties. The formation of residual stresses and distortion originates from the thermal expansion and contraction during welding heating and cooling, respectively.

Zhang, Wei [ORNL

2011-01-01T23:59:59.000Z

27

Estimation of Sensible and Latent Heat Fluxes from Soil Surface Temperature Using a Linear Air-Land Heat Transfer Model  

Science Conference Proceedings (OSTI)

The authors present a linearized model of the heat transfer between the soil layer and the atmosphere. Using this model, the moisture availability at the surface can be estimated from the diurnal variations of the soil surface temperature and ...

Fujio Kimura; Yugo Shimizu

1994-04-01T23:59:59.000Z

28

Engineering Model of Liquid Storage Utility Tank for Heat Transfer Analysis  

SciTech Connect

The utility or chemical storage tank requires special engineering attention and heat transfer analysis because the tank content is very sensitive to temperature and surrounding environment such as atmospheric or outside air, humidity, and solar radiation heat. A simplified heat transfer model was developed to calculate the liquid content temperature of utility storage tank. The content of the utility storage tanks can be water or any other chemical liquid. An engineering model of liquid storage tank for heat transfer analysis and temperature calculations are presented and discussed in the examples of Tanks No. 1 containing oxalic acid and No. 2 containing sodium tetraphenylborate solution.

Kwon, K.C.

1995-09-27T23:59:59.000Z

29

Heat transfer. [heat transfer roller employing a heat pipe  

SciTech Connect

A heat transfer roller embodying a heat pipe is disclosed. The heat pipe is mounted on a shaft, and the shaft is adapted for rotation on its axis.

Sarcia, D.S.

1978-05-23T23:59:59.000Z

30

Estimating Heat and Mass Transfer Processes in Green Roof Systems: Current Modeling Capabilities and Limitations (Presentation)  

Science Conference Proceedings (OSTI)

This presentation discusses estimating heat and mass transfer processes in green roof systems: current modeling capabilities and limitations. Green roofs are 'specialized roofing systems that support vegetation growth on rooftops.'

Tabares Velasco, P. C.

2011-04-01T23:59:59.000Z

31

Heat transfer system  

DOE Patents (OSTI)

A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

Not Available

1980-03-07T23:59:59.000Z

32

Heat transfer system  

DOE Patents (OSTI)

A heat transfer system for a nuclear reactor. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

McGuire, Joseph C. (Richland, WA)

1982-01-01T23:59:59.000Z

33

Finite-volume model for chemical vapor infiltration incorporating radiant heat transfer. Interim report  

SciTech Connect

Most finite-volume thermal models account for the diffusion and convection of heat and may include volume heating. However, for certain simulation geometries, a large percentage of heat flux is due to thermal radiation. In this paper a finite-volume computational procedure for the simulation of heat transfer by conduction, convection and radiation in three dimensional complex enclosures is developed. The radiant heat transfer is included as a source term in each volume element which is derived by Monte Carlo ray tracing from all possible radiating and absorbing faces. The importance of radiative heat transfer is illustrated in the modeling of chemical vapor infiltration (CVI) of tubes. The temperature profile through the tube preform matches experimental measurements only when radiation is included. An alternative, empirical approach using an {open_quotes}effective{close_quotes} thermal conductivity for the gas space can match the initial temperature profile but does not match temperature changes that occur during preform densification.

Smith, A.W.; Starr, T.L. [Georgia Institute of Technology, Atlanta, GA (United States). School of Materials Science and Engineering

1995-05-01T23:59:59.000Z

34

Modeling of data center airflow and heat transfer: State of the art and future trends  

Science Conference Proceedings (OSTI)

An assessment of the current thermal modeling methodologies for data centers is presented, with focus on the use of computational fluid dynamics and heat transfer as analysis tools, and model validation. Future trends in reduced or compact modeling of ... Keywords: Data center, Reduced order models, Thermal modeling

Jeffrey Rambo; Yogendra Joshi

2007-06-01T23:59:59.000Z

35

Models for Metal Hydride Particle Shape, Packing, and Heat Transfer  

E-Print Network (OSTI)

A multiphysics modeling approach for heat conduction in metal hydride powders is presented, including particle shape distribution, size distribution, granular packing structure, and effective thermal conductivity. A statistical geometric model is presented that replicates features of particle size and shape distributions observed experimentally that result from cyclic hydride decreptitation. The quasi-static dense packing of a sample set of these particles is simulated via energy-based structural optimization methods. These particles jam (i.e., solidify) at a density (solid volume fraction) of 0.665+/-0.015 - higher than prior experimental estimates. Effective thermal conductivity of the jammed system is simulated and found to follow the behavior predicted by granular effective medium theory. Finally, a theory is presented that links the properties of bi-porous cohesive powders to the present systems based on recent experimental observations of jammed packings of fine powder. This theory produces quantitative experimental agreement with metal hydride powders of various compositions.

Kyle C. Smith; Timothy S. Fisher

2012-05-04T23:59:59.000Z

36

Modelling of heat transfer at glass/mould interface in press and blow forming processes  

Science Conference Proceedings (OSTI)

Numerical models may play an important role in the optimization of the quality of hollow-ware glass articles in glass industry. Due to the complexity of the phenomena involved a coupling between thermal and mechanical aspects is crucial. One of the key ... Keywords: Finite elements, Glass forming, Heat conduction, Heat transfer coefficient, Interface element, Press/blow process

Sébastien Grégoire; José M. A. César de Sá; Philippe Moreau; Dominique Lochegnies

2007-08-01T23:59:59.000Z

37

Transient PVT measurements and model predictions for vessel heat transfer. Part II.  

SciTech Connect

Part I of this report focused on the acquisition and presentation of transient PVT data sets that can be used to validate gas transfer models. Here in Part II we focus primarily on describing models and validating these models using the data sets. Our models are intended to describe the high speed transport of compressible gases in arbitrary arrangements of vessels, tubing, valving and flow branches. Our models fall into three categories: (1) network flow models in which flow paths are modeled as one-dimensional flow and vessels are modeled as single control volumes, (2) CFD (Computational Fluid Dynamics) models in which flow in and between vessels is modeled in three dimensions and (3) coupled network/CFD models in which vessels are modeled using CFD and flows between vessels are modeled using a network flow code. In our work we utilized NETFLOW as our network flow code and FUEGO for our CFD code. Since network flow models lack three-dimensional resolution, correlations for heat transfer and tube frictional pressure drop are required to resolve important physics not being captured by the model. Here we describe how vessel heat transfer correlations were improved using the data and present direct model-data comparisons for all tests documented in Part I. Our results show that our network flow models have been substantially improved. The CFD modeling presented here describes the complex nature of vessel heat transfer and for the first time demonstrates that flow and heat transfer in vessels can be modeled directly without the need for correlations.

Felver, Todd G.; Paradiso, Nicholas Joseph; Winters, William S., Jr.; Evans, Gregory Herbert; Rice, Steven F.

2010-07-01T23:59:59.000Z

38

Heat transfer dynamics  

Science Conference Proceedings (OSTI)

As heat transfer technology increases in complexity, it becomes more difficult for those without thermal dynamics engineering training to choose between competitive heat transfer systems offered to meet their drying requirements. A step back to the basics of heat transfer can help professional managers and papermakers make informed decisions on alternative equipment and methods. The primary forms of heat and mass transfer are reviewed with emphasis on the basics, so a practical understanding of each is gained. Finally, the principles and benefits of generating infrared energy by combusting a gaseous hydrocarbon fuel are explained.

Smith, T.M. (Marsden, Inc., Pennsauken, NJ (United States))

1994-08-01T23:59:59.000Z

39

Applied heat transfer  

Science Conference Proceedings (OSTI)

Heat transfer principles are discussed with emphasis on the practical aspects of the problems. Correlations for heat transfer and pressure drop from several worldwide sources for flow inside and outside of tubes, including finned tubes are presented, along with design and performance calculations of heat exchangers economizers, air heaters, condensers, waste-heat boilers, fired heaters, superheaters, and boiler furnaces. Vibration analysis for tube bundles and heat exchangers are also discussed, as are estimating gas-mixture properties at atmospheric and elevated pressures and life-cycle costing techniques. (JMT)

Ganapathy, V.

1982-01-01T23:59:59.000Z

40

A 2-D Test Problem for CFD Modeling Heat Transfer in Spent Fuel Transfer Cask Neutron Shields  

SciTech Connect

In the United States, commercial spent nuclear fuel is typically moved from spent fuel pools to outdoor dry storage pads within a transfer cask system that provides radiation shielding to protect personnel and the surrounding environment. The transfer casks are cylindrical steel enclosures with integral gamma and neutron radiation shields. Since the transfer cask system must be passively cooled, decay heat removal from spent nuclear fuel canister is limited by the rate of heat transfer through the cask components, and natural convection from the transfer cask surface. The primary mode of heat transfer within the transfer cask system is conduction, but some cask designs incorporate a liquid neutron shield tank surrounding the transfer cask structural shell. In these systems, accurate prediction of natural convection within the neutron shield tank is an important part of assessing the overall thermal performance of the transfer cask system. The large-scale geometry of the neutron shield tank, which is typically an annulus approximately 2 meters in diameter but only 5-10 cm in thickness, and the relatively small scale velocities (typically less than 5 cm/s) represent a wide range of spatial and temporal scales that contribute to making this a challenging problem for computational fluid dynamics (CFD) modeling. Relevant experimental data at these scales are not available in the literature, but some recent modeling studies offer insights into numerical issues and solutions; however, the geometries in these studies, and for the experimental data in the literature at smaller scales, all have large annular gaps that are not prototypic of the transfer cask neutron shield. This paper presents results for a simple 2-D problem that is an effective numerical analog for the neutron shield application. Because it is 2-D, solutions can be obtained relatively quickly allowing a comparison and assessment of sensitivity to model parameter changes. Turbulence models are considered as well as the tradeoff between steady state and transient solutions. Solutions are compared for two commercial CFD codes, FLUENT and STAR-CCM+. The results can be used to provide input to the CFD Best Practices for this application. Following study results for the 2-D test problem, a comparison of simulation results is provided for a high Rayleigh number experiment with large annular gap. Because the geometry of this validation is significantly different from the neutron shield, and due to the critical nature of this application, the argument is made for new experiments at representative scales

Zigh, Ghani; Solis, Jorge; Fort, James A.

2011-01-14T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

On exact and perturbation solutions to nonlinear equations for heat transfer models  

E-Print Network (OSTI)

We analyze some exact and approximate solutions to nonlinear equations for heat transfer models. We prove that recent results derived from a method based on Lie algebras are either trivial or wrong. We test a simple analytical expression based on the hypervirial theorem and also discuss earlier perturbation results.

Francisco M. Fernández

2009-11-01T23:59:59.000Z

42

Complex Geometry Creation and Turbulent Conjugate Heat Transfer Modeling  

Science Conference Proceedings (OSTI)

The multiphysics capabilities of COMSOL provide the necessary tools to simulate the turbulent thermal-fluid aspects of the High Flux Isotope Reactor (HFIR). Version 4.1, and later, of COMSOL provides three different turbulence models: the standard k-{var_epsilon} closure model, the low Reynolds number (LRN) k-{var_epsilon} model, and the Spalart-Allmaras model. The LRN meets the needs of the nominal HFIR thermal-hydraulic requirements for 2D and 3D simulations. COMSOL also has the capability to create complex geometries. The circular involute fuel plates used in the HFIR require the use of algebraic equations to generate an accurate geometrical representation in the simulation environment. The best-estimate simulation results show that the maximum fuel plate clad surface temperatures are lower than those predicted by the legacy thermal safety code used at HFIR by approximately 17 K. The best-estimate temperature distribution determined by COMSOL was then used to determine the necessary increase in the magnitude of the power density profile (PDP) to produce a similar clad surface temperature as compared to the legacy thermal safety code. It was determined and verified that a 19% power increase was sufficient to bring the two temperature profiles to relatively good agreement.

Bodey, Isaac T [ORNL; Arimilli, Rao V [ORNL; Freels, James D [ORNL

2011-01-01T23:59:59.000Z

43

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

Flow, Transport, and Heat Transfer in Porous and Fracturedtransport, and heat transfer in porous and fracturedflow, chemical transport, and heat transfer in rock. These

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

44

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

transport, and heat transfer processes in porous media. 2.1.mass transport, and heat-transfer processes through porousinvolved. These heat-transfer processes are complicated by

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

45

A comparison of two heat transfer models for estimating thermal drawdown in Hot Dry Rock reservoirs  

DOE Green Energy (OSTI)

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 240/sup 0/C to 150/sup 0/C 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.

Robinson, B.A.; Kruger, P.

1988-01-01T23:59:59.000Z

46

Whole-Building Energy Simulation with a Three-Dimensional Ground-Coupled Heat Transfer Model: Preprint  

DOE Green Energy (OSTI)

A three-dimensional, finite-element, heat-transfer computer program was developed to study ground-coupled heat transfer from buildings. It was used in conjunction with the SUNREL whole-building energy simulation program to analyze ground-coupled heat transfer from buildings, and the results were compared with the simple ground-coupled heat transfer models used in whole-building energy simulation programs. The detailed model provides another method of testing and refining the simple models and analyzing complex problems. This work is part of an effort to improve the analysis of the ground-coupled heat transfer in building energy simulation programs. The output from this detailed model and several others will form a set of reference results for use with the BESTEST diagnostic procedure. We anticipate that the results from the work will be incorporated into ANSI/ASHRAE 140-2001, Standard Method of Test for the Evaluation of Building Energy Analysis Computer Programs.

Deru, M.; Judkoff, R.; Neymark, J.

2002-08-01T23:59:59.000Z

47

Original article: Comparison of numerical models in radiative heat transfer with application to circuit-breaker simulations  

Science Conference Proceedings (OSTI)

Two different modeling approaches for the numerical computation of the radiation energy exchange in the context of the simulation of high-voltage circuit breakers are investigated. These are the basic Radiative Transfer Equation method and the P1 model ... Keywords: CFD modeling, Circuit breakers, Finite volume discretization, P1 model, Radiative heat transfer

Matthieu Melot; Jean-Yves TréPanier; Ricardo Camarero; Eddy Petro

2012-08-01T23:59:59.000Z

48

Application Of A Spherical-Radial Heat Transfer Model To Calculate  

Open Energy Info (EERE)

source source History View New Pages Recent Changes All Special Pages Semantic Search/Querying Get Involved Help Apps Datasets Community Login | Sign Up Search Page Edit History Facebook icon Twitter icon » Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Application Of A Spherical-Radial Heat Transfer Model To Calculate Geothermal Gradients From Measurements In Deep Boreholes Details Activities (0) Areas (0) Regions (0) Abstract: This paper presents estimates of the undisturbed formation temperatures in a geothermal exploration well drilled in the Ceboruco area in the western part of the Mexican Volcanic Belt. The method used assumes

49

Modeling of Heat Transfer in Rooms in the Modelica Buildings Library  

E-Print Network (OSTI)

for one-dimensional heat conduction in a solid only needs todifferent models to compute heat conduction through opaqueone-dimensional heat conduction through multi-layered

Wetter, Michael

2013-01-01T23:59:59.000Z

50

Heat transfer and heat exchangers reference handbook  

Science Conference Proceedings (OSTI)

The purpose of this handbook is to provide Rocky Flats personnel with an understanding of the basic concepts of heat transfer and the operation of heat exchangers.

Not Available

1991-01-15T23:59:59.000Z

51

Application of mechanistic models for flow distribution and heat transfer in finned tube bundles.  

E-Print Network (OSTI)

?? The focus of this thesis was heat transfer and pressure drop in staggered tube bundles with solid and serrated fins. The first part of… (more)

Eikill, Astrid Oygarden

2013-01-01T23:59:59.000Z

52

Heat transfer modeling at an interface between a porous medium and a free region.  

E-Print Network (OSTI)

??This work deals with the study of heat transfer between a porous medium and a free medium, using multi scale approaches. First, we derive the… (more)

D'hueppe, Aliénor

2011-01-01T23:59:59.000Z

53

The Development of a Non-Equilibrium Dispersed Flow Film Boiling Heat Transfer Modeling Package.  

E-Print Network (OSTI)

??The dispersed flow film boiling (DFFB) heat transfer regime is important to several applications including cryogenics, rocket engines, steam generators, and in the safety analysis… (more)

Meholic, Michael

2011-01-01T23:59:59.000Z

54

Analysis of Heat Transfer in Metal Hydride Based Hydrogen Separation  

DOE Green Energy (OSTI)

This thesis presents a transient heat transfer analysis to model the heat transfer in the Pd/k packed column, and the impact of adding metallic foam.

Fleming, W.H. Jr.

1999-10-20T23:59:59.000Z

55

Modeling with finite element the convective heat transfer in civil building EPS insulated walls  

Science Conference Proceedings (OSTI)

In this paper we present the analysis of convective heat transfer in the walls of a house insulated with polystyrene. In the first part we make an evaluation of the insulation that is currently used in the houses. We start the simulation using a real ... Keywords: convective heat transfer, dew-point, finite element, polystyrene insulation

Madalina Xenia Calbureanu; Mihai Lungu; Dragos Tutunea; Raluca Malciu; Alexandru Dima

2010-10-01T23:59:59.000Z

56

HEAT TRANSFER METHOD  

DOE Patents (OSTI)

A method is given for increasing burn-out heat fluxes under nucleate boiling conditions in heat exchanger tubes without incurring an increase in pumping power requirements. This increase is achieved by utilizing a spinning flow having a rotational velocity sufficient to produce a centrifugal acceleration of at least 10,000 g at the tube wall. At this acceleration the heat-transfer rate at burn out is nearly twice the rate which can be achieved in a similar tube utilizing axial flow at the same pumping power. At higher accelerations the improvement over axial flow is greater, and heat fluxes in excess of 50 x 10/sup 6/ Btu/hr/sq ft can be achieved.

Gambill, W.R.; Greene, N.D.

1960-08-30T23:59:59.000Z

57

Three-Dimensional Modeling of Shape Memory Polymers Considering Finite Deformations and Heat Transfer  

E-Print Network (OSTI)

Shape memory polymers (SMPs) are a relatively new class of active materials that can store a temporary shape and return to the original configuration upon application of a stimulus such as temperature. This shape changing ability has led to increased interest in their use for biomedical and aerospace applications. A major challenge, however, in the advancement of these applications is the ability to accurately predict the material behavior for complex geometries and boundary conditions. This work addresses this challenge by developing an experimentally calibrated and validated constitutive model that is implemented as a user material subroutine in Abaqus ? a commercially available finite element software package. The model is formulated in terms of finite deformations and assumes the SMP behaves as a thermoelastic material, for which the response is modeled using a compressible neo-Hookean constitutive equation. An internal state variable, the glassy volume fraction, is introduced to account for the phase transformation and associated stored deformation upon cooling from the rubbery phase to the glassy phase and subsequently recovered upon heating. The numerical implementation is performed such that a system of equations is solved using a Newton-Raphson method to find the updated stress in the material. The conductive heat transfer is incorporated through solving Fourier's law simultaneously with the constitutive equations. To calibrate and validate the model parameters, thermomechanical experiments are performed on an amorphous, thermosetting polyurethane shape memory polymer. Strains of 10-25% are applied and both free recovery (zero load) and constrained displacement recovery boundary conditions are considered for each value of applied strain. Using the uniaxial experimental data, the model is then calibrated and compared to the 1-D experimental results. The validated finite element analysis tool is then used to model biomedical devices, including cardiovascular tubes and thrombectomy devices, fabricated from shape memory polymers. The effects of heat transfer and complex thermal boundary conditions are evaluated using coupled thermal-displacement analysis, for which the thermal material properties were experimentally calibrated.

Volk, Brent 1985-

2012-12-01T23:59:59.000Z

58

Validated, unified model for optics and heat transfer in line-axis concentrating solar energy collectors  

SciTech Connect

A rigorous numerical simulation model for the prediction of the combined optical and thermofluid behaviour of line-axis concentrating solar energy collectors combines two-dimensional steady-state finite element analysis of convective heat transfer and ray-trace techniques. The optical analysis considers both direct and diffuse insolation components and is therefore useful for the analysis of compound parabolic concentrating collectors. Experiments using Mach-Zehnder interferometry indicate a parametric range for which such a two-dimensional representation is valid.

Eames, P.C.; Norton, B. (Univ. of Ulster (United Kingdom))

1993-04-01T23:59:59.000Z

59

Electromagnetic and Heat Transfer Modeling of Microwave Heating in Domestic Ovens.  

E-Print Network (OSTI)

??Microwave (MW) ovens are used extensively for heating a variety of not-ready-to-eat food products. It is vital to achieve target temperature uniformly throughout the food… (more)

Pitchai, Krishnamoorthy

2011-01-01T23:59:59.000Z

60

Modeling and Simulation of the ITER First Wall/Blanket Primary Heat Transfer System  

SciTech Connect

ITER inductive power operation is modeled and simulated using a thermal-hydraulics system code (RELAP5) integrated with a 3-D CFD (SC-Tetra) code. The Primary Heat Transfer System (PHTS) functions are predicted together with the main parameters operational ranges. The control algorithm strategy and derivation are summarized as well. The First Wall and Blanket modules are the primary components of PHTS, used to remove the major part of the thermal heat from the plasma. The modules represent a set of flow channels in solid metal structure that serve to absorb the radiation heat and nuclear heating from the fusion reactions and to provide shield for the vacuum vessel. The blanket modules are water cooled. The cooling is forced convective with constant blanket inlet temperature and mass flow rate. Three independent water loops supply coolant to the three blanket sectors. The main equipment of each loop consists of a pump, a steam pressurizer and a heat exchanger. A major feature of ITER is the pulsed operation. The plasma does not burn continuously, but on intervals with large periods of no power between them. This specific feature causes design challenges to accommodate the thermal expansion of the coolant during the pulse period and requires active temperature control to maintain a constant blanket inlet temperature.

Ying, Alice [University of California, Los Angeles; Popov, Emilian L [ORNL

2011-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

A multiple-relaxation-time lattice Boltzmann model for convection heat transfer in porous media  

E-Print Network (OSTI)

In this paper, a multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is developed for simulating convection heat transfer in porous media at the representative elementary volume scale. In the model, a MRT-LB equation is used to simulate the flow field, while another MRT-LB equation is employed to simulate the temperature field. The effect of the porous media is considered by introducing the porosity into the equilibrium moments, and adding a forcing term to the MRT-LB equation of the flow field in the moment space. The proposed MRT-LB model is validated by numerical simulations of several two-dimensional convection problems in porous media. The numerical results predicted by the present MRT-LB model agree well with those reported in the literature.

Q. Liu; Y. L. He; Q. Li

2013-08-09T23:59:59.000Z

62

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

fluid flow and heat-transfer processes. The physicalcoupled fluid-flow and heat-transfer processes has proven toin which flow and heat transfer processes along drifts are

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

63

Heat Transfer Fluids Containing Nanoparticles  

commercial and industrial heat-transfer applications. ... Refrigeration and other cooling systems Nuclear reactors Aerospace Defense Grinding and ...

64

HEAT TRANSFER IN UNDERGROUND HEATING EXPERIMENTS IN GRANITE, STRIPA, SWEDEN  

E-Print Network (OSTI)

Analysis of. Nonlinear Heat Transfer Problems." Report no.Berkeley, Ca. , APPENDIX A. HEAT TRANSFER BY CONDUCTION ANDMeeting, Technical Session on Heat Transfer in Nuclear Waste

Chan, T.

2010-01-01T23:59:59.000Z

65

Numerical modeling of pool spreading, heat transfer and evaporation in liquefied natural gas (LNG).  

E-Print Network (OSTI)

?? This master's thesis is a continuation of previous theses written at ComputIT AS. It treats heat transfer to LNG pools boiling on water through… (more)

Myrmo, Øystein

2011-01-01T23:59:59.000Z

66

Exploring the Limits of Boiling and Evaporative Heat Transfer Using Micro/Nano Structures  

E-Print Network (OSTI)

Comparison of various heat transfer coefficient models inpool boiling In summary, high heat transfer coefficientin boiling heat transfer can be generally explained by the

Lu, Ming-Chang

2010-01-01T23:59:59.000Z

67

Thermal-radiation heat-transfer model for degraded cores. [PWR; BWR  

SciTech Connect

One consequence of the accident at the Three Mile Island Unit 2 (TMI-2) nuclear power plant is a realization by the nuclear power technical community that there is a need for calculational tools that can be used to analyze the TMI-2 accident and to investigate hypothetical situations involving degraded light-water reactor (LWR) cores. As a result, there are now several ongoing modeling and code development efforts in the United States among which is the development of the MIMAS (Multifield Integrated Meltdown Analysis System code) at the Los Alamos National Laboratory. This paper describes a thermal-radiation heat-transfer model for LWR degraded cores that has been developed for the MIMAS code.

Tomkins, J.L.

1983-01-01T23:59:59.000Z

68

A diffusion-kinetic model for pulverized-coal combustion and heat-and-mass transfer in a gas stream  

SciTech Connect

A diffusion-kinetic model for pulverized-coal combustion and heat-and-mass transfer in a gas stream is proposed, and the results of numerical simulation of the burnout dynamics of Kansk-Achinsk coals in the pulverized state at different treatment conditions and different model parameters are presented. The mathematical model describes the dynamics of thermochemical conversion of solid organic fuels with allowance for complex physicochemical phenomena of heat-and-mass exchange between coal particles and the gaseous environment.

E.A. Boiko; S.V. Pachkovskii [Polytechnic Institute, Federal University of Siberia, Krasnoyarsk (Russian Federation)

2008-12-15T23:59:59.000Z

69

3D CFD ELECTROCHEMICAL AND HEAT TRANSFER MODEL OF AN INTERNALLY MANIFOLDED SOLID OXIDE ELECTROLYSIS CELL  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in an internally manifolded planar solid oxide electrolysis cell (SOEC) stack. This design is being evaluated at the Idaho National Laboratory for hydrogen production from nuclear power and process heat. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, operating potential, steam-electrode gas composition, oxygen-electrode gas composition, current density and hydrogen production over a range of stack operating conditions. Single-cell and five-cell results will be presented. Flow distribution through both models is discussed. Flow enters from the bottom, distributes through the inlet plenum, flows across the cells, gathers in the outlet plenum and flows downward making an upside-down ''U'' shaped flow pattern. Flow and concentration variations exist downstream of the inlet holes. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, oxygen-electrode and steam-electrode current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicate the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

Grant L. Hawkes; James E. O'Brien; Greg Tao

2011-11-01T23:59:59.000Z

70

A numerical model of convective heat transfer in a three dimensional channel with baffles  

E-Print Network (OSTI)

A numerical investigation of laminar forced convective heat transfer was performed in a three-dimensional channel with baffles in which a uniform heat flux was applied to the top and bottom walls, and the side walls were considered adiabatic. The trade-off between heat transfer enhancement and pressure drop produced by the baffles was studied for periodically fully developed flow (PDF). The numerical analysis was performed using a finite volume approach. The computer code was validated against the experimental results of Goldstein and Kreid (1967) and Beavers et. al. (1970) for a three-dimensional laminar flow in a channel without baffles. Parametric runs were made for Reynolds Numbers (Re) of 150, 250, 3 50, and 450, for blockage ratios (H/Dy) of 0. 5, 0.6, 0. 7, 0.8. Heat transfer behavior was studied for Prandtl Numbers (Pr) of 0. 7 and 7. 0, and for wall thermal conductivity to fluid thermal conductivity ratios (K) of 1, 10, 100 and 1000. It was found that three dimensional effects were present for the range of Reynolds number studied. The pressure drop penalty becomes highly important above blockage ratios of 0.7. Higher heat transfer enhancement was found for high Prandtl numbers (Pr--7. 0) than for low Prandtl numbers (Pr--O. 7). The heat transfer enhancement due to an increase in the thermal conductivity ratio of the solid to the fluid regions is greater than the one obtained by increasing the blockage ratio.

Lopez Buso, Jorge Ricardo

1995-01-01T23:59:59.000Z

71

HEAT TRANSFER IN UNDERGROUND HEATING EXPERIMENTS IN GRANITE, STRIPA, SWEDEN  

E-Print Network (OSTI)

standing of the heat transfer processes associated withto investigate the heat transfer and related processes in an

Chan, T.

2010-01-01T23:59:59.000Z

72

Containment condensing heat transfer. [PWR; BWR  

SciTech Connect

This report presents a mechanistic heat-transfer model that is valid for large scale containment heat sinks. The model development is based on the determination that the condensation is controlled by mass diffusion through the vapor-air boundary layer, and the application of the classic Reynolds' analogy to formulate expressions for the transfer of heat and mass based on hydrodynamic measurements of the momentum transfer. As a result, the analysis depends on the quantification of the shear stress (momentum transfer) at the interface between the condensate film and the vapor-air boundary layer. In addition, the currently used Tagami and Uchida test observations and their range of applicability are explained.

Gido, R.G.; Koestel, A.

1983-01-01T23:59:59.000Z

73

Heat transfer through porous multiphase systems measurement, modelling and applications in printing of coated papers.  

E-Print Network (OSTI)

??This work examines the thermal transfer through porous media by means of measurement of the effective thermal conductivity and modelling of the structural parameters. While… (more)

Gerstner, Philip

2010-01-01T23:59:59.000Z

74

Frame Heat Transfer Research  

NLE Websites -- All DOE Office Websites (Extended Search)

Developing Low-Conductance Window Frames: Capabilities and Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools Arild Gustavsen 1,* , Dariush Arasteh 2 , Bjørn Petter Jelle 3,4 , Charlie Curcija 5 and Christian Kohler 2 1 Department of Architectural Design, History and Technology, Norwegian University of Science and Technology, Alfred Getz vei 3, NO-7491 Trondheim, Norway 2 Windows and Daylighting Group, Lawrence Berkeley National Laboratory, 1 Cyclotron Road Mail Stop 90R3111, Berkeley, CA 94720- 8134, USA 3 Department of Civil and Transport Engineering, Norwegian University of Science and Technology, Høgskoleringen 7A, NO-7491 Trondheim, Norway 4 Department of Building Materials and Structures, SINTEF Building and Infrastructure, Høgskoleringen 7B,NO-7465 Trondheim, Norway

75

Optimization of Phase Change Heat Transfer in Biporous Media  

E-Print Network (OSTI)

transfer analysis of a loop heat pipe with biporous wicks”.Planes”. Frontiers in Heat Pipes Journal 1, 013001 (2010).transfer model of a loop heat pipe with a bidisperse wick

Reilly, Sean

2013-01-01T23:59:59.000Z

76

MOLTEN SALT HEAT TRANSFER FLUID  

thermal energy storage tanks Sandia has developed a heat transfer fluid (HTF) for use at elevated temperatures that has a lower freezing point

77

Handbook of heat transfer fundamentals  

SciTech Connect

This handbook is on the fundamentals of heat transfer. It provides coverage on conduction, convection, and radiation and on thermophysical properties of materials.

Rohsenow, W.M.; Hartnett, J.P.; Ganic, E.N.

1985-01-01T23:59:59.000Z

78

Electrohydrodynamically enhanced condensation heat transfer.  

E-Print Network (OSTI)

??In a condenser the thickness of the liquid condensate film covering the cooled surface constitutes a resistance to the heat transfer. By establishing a non… (more)

Wawzyniak, Markus

2012-01-01T23:59:59.000Z

79

Urban Sewage Delivery Heat Transfer System (2): Heat Transfer  

E-Print Network (OSTI)

The thimble delivery heat-transfer (TDHT) system is one of the primary modes to utilize the energy of urban sewage. Using the efficiency-number of transfer units method ( ), the heat-transfer efficiencies of the parallel-flow and reverse-flow TDTH forms are analyzed and the calculation formulas and characteristic are also given. The results indicate that the efficiency of the parallel-flow form is greater than that of the reverse-flow, so the TDTH system must choose the parallel-flow form. The distance-load ratio (DLR) is defined and the minimum DLR is obtained by the technical and economic feasibility analysis. The paper will provide references for heat-transfer calculation and schematic determination of urban sewage cool or heat source applied delivery heat transfer methods.

Zhang, C.; Wu, R.; Li, X.; Li, G.; Zhuang, Z.; Sun, D.

2006-01-01T23:59:59.000Z

80

Heat Transfer and Energy Diffusion Analysis of Cannula Ground Heat Exchanger  

Science Conference Proceedings (OSTI)

A heat transfer model about fluid flow and heat conduct in cannula ground heat exchanger were given in this article. The heat transfer characteristics were analyzed by means of numerical method of finite element. Affect of difference size of buried tubes ... Keywords: heat transfer, energy diffusion, ground heat exchanger, numerical method, couple mode

Jiang Yan; Gao Qing; Li Ming

2010-10-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

A combined heat transfer and quartz dissolution/deposition model for a hot dry rock geothermal reservoir  

DOE Green Energy (OSTI)

A kinetic model of silica transport has been coupled to a heat transfer model for a Hot Dry Rock (HDR) geothermal reservoir to examine the effect of silica rock-water interactions on fracture aperture and permeability. The model accounts for both the dissolution and deposition of silica. Zones of local dissolution and deposition were predicted, but their effect on aperture and permeability were fairly small for all cases studied. Initial rock temperature, reservoir size, and the ratio of rock surface area to fluid volume have the largest effect on the magnitude of silica mass transferred between the liquid and solid phases. 13 refs., 6 figs.

Robinson, B.A.; Pendergrass, J.

1989-01-01T23:59:59.000Z

82

CFD MODELING OF ITER CABLE-IN-CONDUIT SUPERCONDUCTORS. PART V: COMBINED MOMENTUM AND HEAT TRANSFER IN RIB ROUGHENED PIPES  

Science Conference Proceedings (OSTI)

Computational Fluid Dynamics (CFD) techniques have been proposed and applied in a series of papers to analyze cable-in-conduit conductors (CICC) for the International Thermonuclear Experimental Reactor (ITER). Previous work on the pressure drop in the central channel of ITER CICC is extended here to the problem of combined heat and momentum transfer. The CFD model, solved by the FLUENT commercial code, is first validated against 2D and 3D data from compact heat exchangers, showing good agreement. The Colburn analogy between the friction factor f and the Nusselt number Nu is not verified in the considered 2D geometries, as shown by both experiment and simulation. The validated CFD model is finally applied to the 3D analysis of central channel-like geometries relevant for ITER CICC. It is shown that the heat transfer coefficient on the central channel side stays relatively close to the smooth-pipe (Dittus-Boelter) value.

Zanino, R.; Giors, S. [Dipartimento di Energetica, Politecnico Torino, I-10129 (Italy)

2008-03-16T23:59:59.000Z

83

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

fluid flow, multicomponent transport, and heat transfer in porous and fractured media,fluid flow, solute transport, and heat transfer occur in porous and fractured media.fluid flow, mass transport, and heat-transfer processes through porous and fractured media.

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

84

"Nanotechnology Enabled Advanced Industrial Heat Transfer Fluids"  

DOE Green Energy (OSTI)

ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluids” Improving the efficiency of Industrial Heat Exchangers offers a great opportunity to improve overall process efficiencies in diverse industries such as pharmaceutical, materials manufacturing and food processing. The higher efficiencies can come in part from improved heat transfer during both cooling and heating of the material being processed. Additionally, there is great interest in enhancing the performance and reducing the weight of heat exchangers used in automotives in order to increase fuel efficiency. The goal of the Phase I program was to develop nanoparticle containing heat transfer fluids (e.g., antifreeze, water, silicone and hydrocarbon-based oils) that are used in transportation and in the chemical industry for heating, cooling and recovering waste heat. Much work has been done to date at investigating the potential use of nanoparticle-enhanced thermal fluids to improve heat transfer in heat exchangers. In most cases the effect in a commercial heat transfer fluid has been marginal at best. In the Phase I work, we demonstrated that the thermal conductivity, and hence heat transfer, of a fluid containing nanoparticles can be dramatically increased when subjected to an external influence. The increase in thermal conductivity was significantly larger than what is predicted by commonly used thermal models for two-phase materials. Additionally, the surface of the nanoparticles was engineered so as to have a minimal influence on the viscosity of the fluid. As a result, a nanoparticle-laden fluid was successfully developed that can lead to enhanced heat transfer in both industrial and automotive heat exchangers

Dr. Ganesh Skandan; Dr. Amit Singhal; Mr. Kenneth Eberts; Mr. Damian Sobrevilla; Prof. Jerry Shan; Stephen Tse; Toby Rossmann

2008-06-12T23:59:59.000Z

85

HEAT TRANSFER MEANS  

DOE Patents (OSTI)

A heat exchanger is adapted to unifomly cool a spherical surface. Equations for the design of a spherical heat exchanger hav~g tubes with a uniform center-to-center spining are given. The heat exchanger is illustrated in connection with a liquid-fueled reactor.

Fraas, A.P.; Wislicenus, G.F.

1961-07-11T23:59:59.000Z

86

Dynamics of heat transfer between nano systems  

E-Print Network (OSTI)

We develop a dynamical theory of heat transfer between two nano systems. In particular, we consider the resonant heat transfer between two nanoparticles due to the coupling of localized surface modes having a finite spectral width. We model the coupled nanosystem by two coupled quantum mechanical oscillators, each interacting with its own heat bath, and obtain a master equation for the dynamics of heat transfer. The damping rates in the master equation are related to the lifetimes of localized plasmons in the nanoparticles. We study the dynamics towards the steady state and establish connection with the standard theory of heat transfer in steady state. For strongly coupled nano particles we predict Rabi oscillations in the mean occupation number of surface plasmons in each nano particle.

Svend-Age Biehs; Girish S. Agarwal

2012-10-18T23:59:59.000Z

87

Heat and moisture transfer through clothing  

E-Print Network (OSTI)

R. C. Eberhart (ed), Heat transfer in medicine and biology.Convective and radiative heat transfer coefficients for2008. Study of heat and moisture transfer within multi-layer

Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie

2009-01-01T23:59:59.000Z

88

Controlling the Heat Transfer  

Science Conference Proceedings (OSTI)

Through experimental validation that air conduction is shown to be typically the dominant thermal transport mechanism in the contact region, the heat conduction

89

A transient heat and mass transfer model of residential attics used to simulate radiant barrier retrofits. Part 1: Development  

SciTech Connect

This paper describes a transient heat and mass transfer model of residential attics. The model is used to predict hourly ceiling heat gain/loss in residences with the purpose of estimating reductions in cooling and heating loads produced by radiant barriers. The model accounts for transient conduction, convection, and radiation and incorporates moisture and air transport across the attic. Environmental variables, such as solar loads on outer attic surfaces and sky temperatures, are also estimated. The model is driven by hourly weather data which include: outdoor dry bulb air temperature, horizontal solar and sky radiation, wind speed and direction, relative humidity (or dew point), and cloud cover data. The output of the model includes ceiling heat fluxes, inner and outer heat fluxes from all surfaces, inner and outer surface temperatures, and attic dry bulb air temperatures. The calculated fluxes have been compared to experimental data of side-by-side testing of attics retrofit with radiant barriers. The model predicts ceiling heat flows with an error of less than 10% for most cases.

Medina, M.A. [Texas A and M Univ., Kingsville, TX (United States). Dept. of Mechanical and Industrial Engineering; O`Neal, D.L. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering; Turner, W.D. [Texas Engineering Experiment Station, College Station, TX (United States). Energy Systems Lab.

1998-02-01T23:59:59.000Z

90

Heat Transfer Enhancement in Thermoelectric Power Generation.  

E-Print Network (OSTI)

??Heat transfer plays an important role in thermoelectric (TE) power generation because the higher the heat-transfer rate from the hot to the cold side of… (more)

Hu, Shih-yung

2009-01-01T23:59:59.000Z

91

Characterization and modelling of the heat transfers in a pilot-scale reactor during composting under forced aeration  

SciTech Connect

The paper focused on the modelling of the heat transfers during composting in a pilot-scale reactor under forced aeration. The model took into account the heat production and the transfers by evaporation, convection between material and gas crossing the material, conduction and surface convection between gas and material in bottom and upper parts of the reactor. The model was adjusted thanks to the measurements practised during fifteen composting experiments in which five organic wastes were, each, composted under three constant aeration rates. Heat production was considered proportional to oxygen consumption rate and the enthalpy per mole oxygen consumed was assumed constant. The convective heat transfer coefficients were determined on basis of the continuous measurements of the temperatures of both the lid and the bottom part of the reactor. The model allowed a satisfying prediction of the temperature of the composting material. In most cases, the mean absolute discard between the experimental and the simulated temperatures was inferior to 2.5 Degree-Sign C and the peaks of temperature occurred with less than 8 h delay. For the half of the experiments the temperature discard between the simulated peak and the experimental one was inferior to 5 Degree-Sign C. On basis of the calculation of a stoichiometric production of water through oxidation of the biodegradable organic matter, the simulation of water going out from material as vapour also allowed a rather satisfying prediction of the mass of water in final mixture. The influence of the aeration rate on every type of heat loss was characterized. Finally, the model was used to evaluate the impacts on material temperature caused by the change of the insulation thickness, the ambient temperature, take the lid away, the increase or the decrease of the mass of waste to compost.

Guardia, A. de, E-mail: amaury.de-guardia@irstea.fr [Irstea/Cemagref, UR GERE, 17 Avenue de Cucille, CS 64427, F-35044 Rennes (France); Universite Europeenne de Bretagne, F-35000 Rennes (France); Petiot, C.; Benoist, J.C.; Druilhe, C. [Irstea/Cemagref, UR GERE, 17 Avenue de Cucille, CS 64427, F-35044 Rennes (France); Universite Europeenne de Bretagne, F-35000 Rennes (France)

2012-06-15T23:59:59.000Z

92

Enhanced heat transfer using nanofluids  

DOE Patents (OSTI)

This invention is directed to a method of and apparatus for enhancing heat transfer in fluids such as deionized water. ethylene glycol, or oil by dispersing nanocrystalline particles of substances such as copper, copper oxide, aluminum oxide, or the like in the fluids. Nanocrystalline particles are produced and dispersed in the fluid by heating the substance to be dispersed in a vacuum while passing a thin film of the fluid near the heated substance. The fluid is cooled to control its vapor pressure.

Choi, Stephen U. S. (Lisle, IL); Eastman, Jeffrey A. (Naperville, IL)

2001-01-01T23:59:59.000Z

93

Numerical study on transient heat transfer under soil with plastic mulch in agriculture applications using a nonlinear finite element model  

E-Print Network (OSTI)

In this paper is developed a simple mathematical model of transient heat transfer under soil with plastic mulch in order to determine with numerical studies the influence of different plastic mulches on the soil temperature and the evolutions of temperatures at different depths with time. The governing differential equations are solved by a Galerkin Finite Element Model, taking into account the nonlinearities due to radiative heat exchange between the soil surface, the plastic mulch and the atmosphere. The model was validated experimentally giving good approximation of the model to the measured data. Simulations were run with the validated model in order to determine the optimal combination of mulch optical properties to maximize the soil temperature with a Taguchi's analysis, proving that the material most used nowadays in Colombia is not the optimal and giving quantitative results of the properties the optimal mulch must possess.

De Castro, Carlos Armando

2011-01-01T23:59:59.000Z

94

Full surface local heat transfer coefficient measurements in a model of an integrally cast impingement cooling geometry  

SciTech Connect

Cast impingement cooling geometries offer the gas turbine designer higher structural integrity and improved convective cooling when compared to traditional impingement cooling systems, which rely on plate inserts. In this paper, it is shown that the surface that forms the jets contributes significantly to the total cooling. Local heat transfer coefficient distributions have been measured in a model of an engine wall cooling geometry using the transient heat transfer technique. The method employs temperature-sensitive liquid crystals to measure the surface temperature of large-scale perspex models during transient experiments. Full distributions of local Nusselt number on both surfaces of the impingement plate, and on the impingement target plate, are presented at engine representative Reynolds numbers. The relative effects of the impingement plate thermal boundary condition and the coolant supply temperature on the target plate heat transfer have been determined by maintaining an isothermal boundary condition at the impingement plate during the transient tests. The results are discussed in terms of the interpreted flow field.

Gillespie, D.R.H.; Wang, Z.; Ireland, P.T. [Univ. of Oxford (United Kingdom). Dept. of Engineering Science; Kohler, S.T. [Rolls Royce, Bristol (United Kingdom)

1998-01-01T23:59:59.000Z

95

Nanoscale heat transfer - from computation to experiment  

E-Print Network (OSTI)

Heat transfer can differ distinctly at the nanoscale from that at the macroscale. Recent advancement in

Luo, Tengfei

2013-04-09T23:59:59.000Z

96

A unified numerical framework model for simulating flow, transport, and heat transfer in porous and fractured media  

E-Print Network (OSTI)

or chemical species in a multiphase porous medium system canand radiation in a multiphase, multicomponent, porous mediummultiphase flow, multicomponent transport, and heat transfer in porous

Wu, Yu-Shu

2004-01-01T23:59:59.000Z

97

Modeling near-field radiative heat transfer from sharp objects using a general three-dimensional numerical scattering technique  

E-Print Network (OSTI)

We develop a general numerical method to calculate the nonequilibrium radiative heat transfer between a plate and compact objects of arbitrary shapes, making the first accurate theoretical predictions for the total heat ...

McCauley, Alexander Patrick

98

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

grain-specific heat for each model grid layer, are providedand heat flow is simulated using the 3-D TH model grid (

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

99

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

for Modeling Fluid and Heat Flow in Fractured Porous Media,with fluid and heat flow in fractured porous media arefluid and heat flow in porous media, heat pipe, reservoir simulation, fractured

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

100

A Systematic Study of Longwave Radiative Heating and Cooling within Valleys and Basins Using a Three-Dimensional Radiative Transfer Model  

Science Conference Proceedings (OSTI)

The Monte Carlo code for the physically correct tracing of photons in cloudy atmospheres (MYSTIC) three-dimensional radiative transfer model was used in a parametric study to determine the strength of longwave radiative heating and cooling in ...

Sebastian W. Hoch; C. David Whiteman; Bernhard Mayer

2011-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Optimization of Phase Change Heat Transfer in Biporous Media  

E-Print Network (OSTI)

Aspectcs of Boiling Heat Transfer”. PhD Thesis dissertation,Celled Foams”. Numerical Heat Transfer, Vol. 54, issue 1,Dimensional Fluid Flow and Heat Transfer”. Numerical Heat

Reilly, Sean

2013-01-01T23:59:59.000Z

102

Convective heat transfer in rotating, circular channels  

E-Print Network (OSTI)

Nusselt number values for flow in a rotating reference frame are obtained through computational fluid dynamic (CFD) analysis for Rossby numbers Ro ~1-4 and Reynolds numbers Re ~1,000-2,000. The heat-transfer model is first ...

Hogan, Brenna Elizabeth

2012-01-01T23:59:59.000Z

103

A WSRC-MS-g8-00318 Heat Transfer Model of Above and Underground Insulated Piping  

Office of Scientific and Technical Information (OSTI)

WSRC-MS-g8-00318 Heat Transfer Model of Above and Underground Insulated Piping Systems by K. C. Kwon Westinghouse Savannah River Company Savannah River Site Aiken, South Carolina 29808 A document prepared for ASME CONFERENCE - HEAT EXCHANGER COMMITTEE MEETING 8 , INTERNATIONAL JOINT POWER GENERATION CONFERENCE 1998 at Baltimore, MA, USA from 8/23/98 - 8/26/98. DOE Contract No. DE-AC09-96SR18500 This paper was prepared in connection with work done under the above contract number with the U. S. Department of Energy. By acceptance of this paper, the publisher and/or recipient acknowledges the U. S. Government's right to retain a nonexclusive, royalty-free license in and to any copyright covering this paper, along with the right to reproduce and to authorize others to reproduce all or part of the copyrighted paper.

104

Heat Transfer in Complex Fluids  

SciTech Connect

Amongst the most important constitutive relations in Mechanics, when characterizing the behavior of complex materials, one can identify the stress tensor T, the heat flux vector q (related to heat conduction) and the radiant heating (related to the radiation term in the energy equation). Of course, the expression 'complex materials' is not new. In fact, at least since the publication of the paper by Rivlin & Ericksen (1955), who discussed fluids of complexity (Truesdell & Noll, 1992), to the recently published books (Deshpande et al., 2010), the term complex fluids refers in general to fluid-like materials whose response, namely the stress tensor, is 'non-linear' in some fashion. This non-linearity can manifest itself in variety of forms such as memory effects, yield stress, creep or relaxation, normal-stress differences, etc. The emphasis in this chapter, while focusing on the constitutive modeling of complex fluids, is on granular materials (such as coal) and non-linear fluids (such as coal-slurries). One of the main areas of interest in energy related processes, such as power plants, atomization, alternative fuels, etc., is the use of slurries, specifically coal-water or coal-oil slurries, as the primary fuel. Some studies indicate that the viscosity of coal-water mixtures depends not only on the volume fraction of solids, and the mean size and the size distribution of the coal, but also on the shear rate, since the slurry behaves as shear-rate dependent fluid. There are also studies which indicate that preheating the fuel results in better performance, and as a result of such heating, the viscosity changes. Constitutive modeling of these non-linear fluids, commonly referred to as non-Newtonian fluids, has received much attention. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, coal-water slurries, drilling fluids, mud, etc. It should be noted that sometimes these fluids show Newtonian (linear) behavior for a given range of parameters or geometries; there are many empirical or semi-empirical constitutive equations suggested for these fluids. There have also been many non-linear constitutive relations which have been derived based on the techniques of continuum mechanics. The non-linearities oftentimes appear due to higher gradient terms or time derivatives. When thermal and or chemical effects are also important, the (coupled) momentum and energy equations can give rise to a variety of interesting problems, such as instability, for example the phenomenon of double-diffusive convection in a fluid layer. In Conclusion, we have studied the flow of a compressible (density gradient type) non-linear fluid down an inclined plane, subject to radiation boundary condition. The heat transfer is also considered where a source term, similar to the Arrhenius type reaction, is included. The non-dimensional forms of the equations are solved numerically and the competing effects of conduction, dissipation, heat generation and radiation are discussed. It is observed that the velocity increases rapidly in the region near the inclined surface and is slower in the region near the free surface. Since R{sub 7} is a measure of the heat generation due to chemical reaction, when the reaction is frozen (R{sub 7}=0.0) the temperature distributions would depend only on R{sub 1}, and R{sub 2}, representing the effects of the pressure force developed in the material due to the distribution, R{sub 3} and R{sub 4} viscous dissipation, R{sub 5} the normal stress coefficient, R{sub 6} the measure of the emissivity of the particles to the thermal conductivity, etc. When the flow is not frozen (RP{sub 7} > 0) the temperature inside the flow domain is much higher than those at the inclined and free surfaces. As a result, heat is transferred away from the flow toward both the inclined surface and the free surface with a rate that increases as R{sub 7} increases. For a given temperature, an increase in {zeta} implies that the activation energy is smaller and thus, the reaction ra

Mehrdad Massoudi

2012-01-01T23:59:59.000Z

105

Infrared Thermography applied to measurement of Heat transfer coefficient of water in a pipe heated by Joule effect  

E-Print Network (OSTI)

. Internal sources of heat are due to convection from flow of the heat transfer fluid through the pipes. Heat (material, diameter, spacing, and burial depth), (4) system flow rates, (5) heat transfer fluid properties · heat transfer fluid = 42% propylene glycol @ a flow rate of 350 gpm · heat pump model = Water Furnace

106

Heat Flow, Heat Transfer And Lithosphere Rheology In Geothermal...  

Open Energy Info (EERE)

Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas- Features And Examples Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow,...

107

Available Technologies: Heat Transfer Interface for Thermo ...  

Refrigeration systems; Internal combustion engines; ... The components of the technology could be used to improve heat transfer in industrial, ...

108

Heat Transfer & Alternative Energy Systems Group Staff ...  

Science Conference Proceedings (OSTI)

Heat Transfer and Alternative Energy Systems Group Staff. Staff Listing. Dr. William M. Healy, Leader, Supervisory Mechanical ...

2013-08-07T23:59:59.000Z

109

Acoustically Enhanced Boiling Heat Transfer  

E-Print Network (OSTI)

An acoustic field is used to increase the critical heat flux (CHF) of a flat-boiling-heat-transfer surface. The increase is a result of the acoustic effects on the vapor bubbles. Experiments are performed to explore the effects of an acoustic field on vapor bubbles in the vicinity of a rigid-heated wall. Work includes the construction of a novel heater used to produce a single vapor bubble of a prescribed size and at a prescribed location on a flatboiling surface for better study of an individual vapor bubble's reaction to the acoustic field. Work also includes application of the results from the single-bubble heater to a calibrated-copper heater used for quantifying the improvements in CHF.

Z. W. Douglas; M. K. Smith; A. Glezer

2008-01-07T23:59:59.000Z

110

2.51 Intermediate Heat and Mass Transfer, Fall 2001  

E-Print Network (OSTI)

Analysis, modeling, and design of heat and mass transfer processes with application to common technologies. Unsteady heat conduction in one or more dimensions, steady conduction in multidimensional configurations, numerical ...

Lienhard, John H., 1961-

111

Heat transfer via dropwise condensation on hydrophobic microstructured surfaces  

E-Print Network (OSTI)

Dropwise condensation has the potential to greatly increase heat transfer rates. Heat transfer coefficients by dropwise condensation and film condensation on microstructured silicon chips were compared. Heat transfer ...

Ruleman, Karlen E. (Karlen Elizabeth)

2009-01-01T23:59:59.000Z

112

A Mixed-Dimensionality Modeling Approach for Interaction of Heterogeneous Steam Reforming Reactions and Heat Transfer.  

E-Print Network (OSTI)

??Hydrogen is most often produced on an industrial scale by catalytic steam methane reforming, an equilibrium-limited, highly endothermic process requiring the substantial addition of heat… (more)

Valensa, Jeroen

2009-01-01T23:59:59.000Z

113

Heat exchanger device and method for heat removal or transfer  

Science Conference Proceedings (OSTI)

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.

Koplow, Jeffrey P. (San Ramon, CA)

2012-07-24T23:59:59.000Z

114

Handbook of heat transfer applications (2nd edition)  

Science Conference Proceedings (OSTI)

The applications of heat transfer in engineering problems are considered. Among the applications discussed are: mass transfer cooling; heat exchangers; and heat pipes. Consideration is also given to: heat transfer in nonNewtonian fluids; fluidized and packed beds; thermal energy storage; and heat transfer in solar collectors. Additional topics include: heat transfer in buildings; cooling towers and ponds; and geothermal heat transfer.

Rohsenow, W.M.; Hartnett, J.P.; Ganic, E.N.

1985-01-01T23:59:59.000Z

115

Transient heat transfer through walls and thermal bridges. numerical modelling: methodology and validation  

Science Conference Proceedings (OSTI)

The current advanced numerical codes for the energy audits carry out 0-dimensional simulation (i.e., one computational node representing the thermal zone), underestimating the effects of thermal bridges on the seasonal heating demand of buildings. The ...

Fabrizio Ascione; Filippo de' Rossi; Nicola Bianco; Giuseppe Peter Vanoli

2012-12-01T23:59:59.000Z

116

3D CFD Electrochemical and Heat Transfer Model of an Integrated-Planar Solid Oxide Electrolysis Cells  

DOE Green Energy (OSTI)

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots of local electrolyte temperature, current density, and Nernst potential indicated the effects of heat transfer, reaction cooling/heating, and change in local gas composition. Results are discussed for using this design in the electrolysis mode. Discussion of thermal neutral voltage, enthalpy of reaction, hydrogen production, cell thermal efficiency, cell electrical efficiency, and Gibbs free energy are discussed and reported herein.

Grant Hawkes; James E. O'Brien

2008-10-01T23:59:59.000Z

117

Heat transfer pathways in underfloor air distribution (UFAD) systems  

E-Print Network (OSTI)

the following heat transfer processes: conduction throughtudes of the major heat transfer processes in a typical room

Bauman, F.; Jin, H.; Webster, T.

2006-01-01T23:59:59.000Z

118

Heat transfer in freeboard region of fluidized beds  

SciTech Connect

This research involved the study of heat transfer and fluid mechanic characteristics around a horizontal tube in the freeboard region of fluidized beds. Heat transfer coefficients were experimetnally measured for different bed temperatures, particle sizes, gas flow rates, and tube elevations in the freeboard region of air fluidized beds at atmospheric pressure. Local heat transfer coefficients were found to vary significantly with angular position around the tube. Average heat transfer coefficients were found to decrease with increasing freeboard tube elevation and approach the values for gas convection plus radiation for any given gas velocity. For a fixed tube elevation, heat transfer coefficients generally increased with increasing gas velocity and with high particle entrainment they can approach the magnitudes found for immersed tubes. Heat transfer coefficients were also found to increase with increasing bed temperature. It was concluded that this increase is partly due to increase of radiative heat transfer and partly due to change of thermal properties of the fluidizing gas and particles. To investigate the fluid mechanic behavior of gas and particles around a freeboard tube, transient particle tube contacts were measured with a special capacitance probe in room temperature experiments. The results indicated that the tube surface experiences alternating dense and lean phase contacts. Quantitative information for local characteristics was obtained from the capacitance signals and used to develop a phenomenological model for prediction of the heat transfer coefficients around freeboard tubes. The packet renewal theory was modified to account for the dense phase heat transfer and a new model was suggested for the lean phase heat transfer. Finally, an empirical freeboard heat transfer correlation was developed from functional analysis of the freeboard heat transfer data using nondimensional groups representing gas velocity and tube elevation.

Biyikli, S.; Tuzla, K.; Chen, J.C.

1983-10-01T23:59:59.000Z

119

Liquid Crystal Technique Application for Heat Transfer Investigation in a Fin-Tube Heat Exchanger Element  

Science Conference Proceedings (OSTI)

The use of thermochromic liquid crystal technique (LCT) and true-colour image processing system in heat transfer modelling is described. Experimental procedure, led on rig at Technical University of Gdansk, cover full-field flow patterns in heat exchanger ... Keywords: heat transfer, thermochromic liquid crystals, vortex generator, wind tunnel

M. Wierzbowski; J. Stasiek

2002-04-01T23:59:59.000Z

120

Heat Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas-  

Open Energy Info (EERE)

Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas- Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas- Features And Examples Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow, Heat Transfer And Lithosphere Rheology In Geothermal Areas- Features And Examples Details Activities (5) Areas (5) Regions (0) Abstract: Surface heat flow measurements over active geothermal systems indicate strongly positive thermal anomalies. Whereas in "normal" geothermal settings, the surface heat flow is usually below 100-120 mW m- 2, in active geothermal areas heat flow values as high as several watts per meter squared can be found. Systematic interpretation of heat flow patterns sheds light on heat transfer mechanisms at depth on different lateral, depth and time scales. Borehole temperature profiles in active geothermal

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Enhanced heat transfer for thermionic power modules  

DOE Green Energy (OSTI)

The thermionic power module is capable of operating at very high heat fluxes, which in turn serve to reduce capital costs. The most efficient operation also requires uniform heat fluxes. The development of enhanced heat transfer systems is required to meet the demand for high heat fluxes (>20 w/cm/sup 2/) at high temperatures (>1500K) which advanced thermionic power modules place upon combustion systems. Energy transfer from the hot combustion gases may take place by convection, radiation, or a combination of radiation and convection. Enhanced convective heat transfer with a jet impingement system has been demonstrated in a thermionic converter. The recently-developed cellular ceramic radiative heat transfer system has also been applied to a thermionic converter. By comparing the jet impingement and cellular ceramic radiative heat transfer systems, an appropriate system may be selected for utilization in advanced thermionic power modules. Results are reported.

Johnson, D.C.

1981-07-01T23:59:59.000Z

122

Modeling of Heat Transfer in Rooms in the Modelica Buildings Library  

E-Print Network (OSTI)

infrared radia- tion and solar radiation. Figure 1 shows theIn the window model, a solar radiation balance is solved forexterior shade. The model solar radiation balance implements

Wetter, Michael

2013-01-01T23:59:59.000Z

123

Heat Transfer In Turbine Mid Structures.  

E-Print Network (OSTI)

??In order to estimate the life time of a cooled gas turbine component, knowledge of the heat transfer is essential in order to predict the… (more)

Abou-Taouk, Abdallah

2006-01-01T23:59:59.000Z

124

Enhanced Heat Transfer in Composite Materials.  

E-Print Network (OSTI)

??Many composite materials are composed of a matrix reinforced with fibers. Carbon fiber composites are currently being used for high heat transfer applications. Carbon fibers… (more)

Pathak, Sayali V.

2013-01-01T23:59:59.000Z

125

Interface Heat Transfer Effects for Solidification Processes  

Science Conference Proceedings (OSTI)

The solidification rate of a casting is governed by the rate of heat extraction, which in turn is dominated by the rate of heat transfer across the casting-mold ...

126

Numerical modelling of heat and mass transfer and optimisation of a natural draft wet cooling tower.  

E-Print Network (OSTI)

??The main contribution of this work is to answer several important questions relating to natural draft wet cooling tower (NDWCT) modelling, design and optimisation. Specifically,… (more)

Williamson, Nicholas J

2007-01-01T23:59:59.000Z

127

HEAT EXCHANGER DEVICE AND METHOD FOR HEAT REMOVAL OR TRANSFER ...  

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 ...

128

Overview of heat transfer and fluid flow problem areas encountered in stirling engine modeling  

SciTech Connect

NASA Lewis Research Center has been managing Stirling engine development programs for over a decade. In addition to contractual programs, this work has included in-house engine testing and development of engine computer models. Attempts to validate Stirling engine computer models with test data have demonstrated that engine thermodynamic losses need better characterization. Various Stirling engine thermodynamic losses and efforts that are underway to characterize these losses are discussed.

Tew, R.C. Jr.

1988-02-01T23:59:59.000Z

129

Development of a Transient Heat and Mass Transfer Model of Residential Attics to Predict Energy Savings Produced by the Use of Radiant Barriers  

E-Print Network (OSTI)

A transient heat and mass transfer model was developed to predict ceiling heat gain/loss through the attic space in residences and to accurately estimate savings in cooling and heating loads produced by the use of radiant barriers. The model accounted for transient conduction, convection and radiation and incorporated moisture and air transport across the attic. Environmental variables such as solar loads on outer attic surfaces and sky temperatures were also estimated. The model was driven by hourly weather data which included: time, outdoor air temperature, horizontal sun and sky radiation, wind speed and direction, relative humidity (dew point), and cloud cover data. The outputs of the model were ceiling heat fluxes, inner and outer heat fluxes from all surfaces, inner and outer surface temperatures and attic air temperatures. Transient conduction was modeled using response factors. Response factors were calculated for each attic component based on construction type. Convective heat transfer was modeled using “flat plate” correlations found in the literature and radiative heat transfer was modeled using radiation enclosure theory. Moisture was incorporated via a condensation/evaporation model. A new procedure was developed to account for attic air stratification. Both forced and natural attic ventilation patterns were added to the model for three types of louver combination arrangements. An iterative technique was used to solve a set of simultaneous heat balance equations. The model predictions were compared to experimental data gathered throughout a three year experimental effort of side-by-side testing of attics retrofit with radiant barriers. The model was compared to the experimental data for a variety of situations which included: different attic insulation levels, various attic airflow rates, cooling and heating seasons, and different radiant barrier orientations. The model predicted ceiling heat flows within 10% for most cases. The model was used to run simulations and parametric studies under a diversity of climates, insulation levels and attic airflow patterns. Model predictions and results were presented on the basis of savings produced by the use of radiant barriers. Hourly, daily, and seasonal predictions by the model were in excellent agreement with observed experimental data and with literature.

Medina, M. A.

1992-12-01T23:59:59.000Z

130

Heat Transfer Characteristics of a Generalized Divided Flow Heat Exchanger  

E-Print Network (OSTI)

The concept of a "Divided-flow" heat exchanger is generalized by locating the shell inlet (or outlet) nozzle off-center such that the two shell sub-streams are unequal and traverse unequal flow paths. The governing equations for heat transfer in such an exchanger are derived and solved leading to an optimization problem. In this problem, the optimal subdivision of heat transfer surface to minimize required overall heat transfer surface, under certain restricted conditions, is sought. It is shown that the off-center nozzle location can be selected judiciously so as to maintain (or even improve heat transfer) while reducing the gross shellside pressure loss. Thus, the pumping costs are minimized without sacrificing heat transfer.

Singh, K. P.

1979-01-01T23:59:59.000Z

131

Mathematical modeling of heat and mass transfer in packed-bed adsorbers/regenerators  

SciTech Connect

Adsorber-regenerators are used extensively in the process industries for gas cleaning and separation. Nonisothermal adsorption is studied by incorporating its mathematical description into a model consisting of the full two-dimensional Navier-Stokes equations and energy and species concentration equations to simulate the processes in fixed-bed industrial adsorber/regenerators. The model partial-differential equations are solved numerically by using well-established computational fluid dynamics techniques. The equilibrium between gas and solid is considered nonlinear, which is described by Freundlich-type equations. The transport and adsorption of a compound from a solvent to and into an adsorbent are described by a two-step process: transport through the film to the outer surface of the particle and diffusion into the porous particle. The effect of fill resistance is discussed, as well as a two-equation turbulence model. Solutions obtained for a typical industrial adsorber/regenerator demonstrate the potential of this method. The computed results for various flow ratios and parameters in the Freundlich equations are shown to be physically plausible.

Gouvalias, G.S.; Markatos, N.C. (National Technical Univ., Athens (Greece). Dept. of Chemical Engineering)

1993-11-01T23:59:59.000Z

132

Inverse Problems in Heat Transfer  

E-Print Network (OSTI)

This chapter presents a stochastic modeling and statistical inference approach to the solution of inverse problems in thermal transport systems. Of particular interest is the inverse heat conduction problem (IHCP) of estimating an unknown boundary heat flux in a conducting solid given temperature data within the domain. Even though deterministic sequential and whole time domain estimation methods have been applied with success over the years for the solution of such problems, we herein introduce stochastic approaches to representing and solving the IHCP. As most engineering systems and processes operate in an uncertain environment, it becomes increasingly important to address their analysis and inverse design in a stochastic manner using statistical data-driven prior and concurrent information on the system response. Recent advances in spectral stochastic modeling, computational Bayesian and spatial statistics enable complete and e#cient solution procedures to such problems. Two distinct approaches to the IHCP are presented in this chapter one based on spectral stochastic modeling and the other on Bayesian inference. Although these techniques are discussed in the context of the IHCP, the methodologies presented are general and applicable to design and estimation problems in other more complex problems in thermal transport systems including problems in the presence of convection, radiation and conduction. 1

Nicholas Zabaras

2004-01-01T23:59:59.000Z

133

An Evaluation of Two Models for Estimation of the Roughness Height for Heat Transfer between the Land Surface and the Atmosphere  

Science Conference Proceedings (OSTI)

Roughness height for heat transfer is a crucial parameter in estimation of heat transfer between the land surface and the atmosphere. Although many empirical formulations have been proposed over the past few decades, the uncertainties associated ...

Z. Su; T. Schmugge; W. P. Kustas; W. J. Massman

2001-11-01T23:59:59.000Z

134

Radiative heat transfer between dielectric bodies  

E-Print Network (OSTI)

The recent development of a scanning thermal microscope (SThM) has led to measurements of radiative heat transfer between a heated sensor and a cooled sample down to the nanometer range. This allows for comparision of the known theoretical description of radiative heat transfer, which is based on fluctuating electrodynamics, with experiment. The theory itself is a macroscopic theory, which can be expected to break down at distances much smaller than 10-8m. Against this background it seems to be reasonable to revisit the known macroscopic theory of fluctuating electrodynamics and of radiative heat transfer.

Svend-Age Biehs

2011-03-16T23:59:59.000Z

135

Numerical investigation of transient heat and mass transfer in a parallel-flow liquid-desiccant absorber  

E-Print Network (OSTI)

model for heat and mass transfer processes in internallyof coupled heat and mass transfer processes in liquidHeat and mass transfer in liquid des- iccant air-conditioning process

Diaz, Gerardo

2010-01-01T23:59:59.000Z

136

High Operating Temperature Heat Transfer Fluids for Solar Thermal...  

NLE Websites -- All DOE Office Websites (Extended Search)

Heat Transfer Fluids for Solar Thermal Power Generation UCLA, UCB, Yale Award Number: DE-EE0005941 | January 9, 2013 | Sungtaek Ju 1.1 Thermochemistry modeling Identified promising...

137

Heat Transfer Enhancement: Second Generation Technology  

E-Print Network (OSTI)

This paper reviews current activity in the field of enhanced heat transfer, with the aim of illustrating the technology and typical applications. Guidelines for application of enhanced surfaces are given, and practical concerns and economics are discussed. Special attention is directed toward use of enhanced surfaces in industrial process heat exchangers and heat recovery equipment.

Bergles, A. E.; Webb, R. L.

1984-01-01T23:59:59.000Z

138

Fundamental heat transfer experiments of heat pipes for turbine cooling  

SciTech Connect

Fundamental heat transfer experiments were carried out for three kinds of heat pipes that may be applied to turbine cooling in future aero-engines. In the turbine cooling system with a heat pipe, heat transfer rate and start-up time of the heat pipe are the most important performance criteria to evaluate and compare with conventional cooling methods. Three heat pipes are considered, called heat pipe A, B, and C, respectively. All heat pipes have a stainless steel shell and nickel sintered powder metal wick. Sodium (Na) was the working fluid for heat pipes A and B; heat pipe C used eutectic sodium-potassium (NaK). Heat pipes B and C included noncondensible gas for rapid start-up. There were fins on the cooling section of heat pipes. In the experiments, an infrared image furnace supplied heat to the heat pipe simulating turbine blade surface conditions. In the results, heat pipe B demonstrated the highest heat flux of 17 to 20 W/cm{sup 2}. The start-up time was about 6 minutes for heat pipe B and about 6 minutes for heat pipe A. Thus, adding noncondensible gas effectively reduced start-up time. Although NaK is a liquid phase at room temperature, the start-up time of heat pipe C (about 7 to 8 minutes) was not shorter than the heat pipe B. The effect of a gravitational force on heat pipe performance was also estimated by inclining the heat pipe at an angle of 90 deg. There was no significant gravitational dependence on heat transport for heat pipes including noncondensible gas.

Yamawaki, S. [Ishikawajima-Harima Heavy Industries Co., Ltd., Tokyo (Japan); Yoshida, T.; Taki, M.; Mimura, F. [National Aerospace Lab., Tokyo (Japan)

1998-07-01T23:59:59.000Z

139

Heat Transfer and Fluid Mechanics - Nuclear Engineering Division (Argonne)  

NLE Websites -- All DOE Office Websites (Extended Search)

Engineering Computation Engineering Computation and Design > Heat Transfer and Fluid Mechanics Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Engineering Simulation Capabilities at Argonne Nuclear Engineering Division The Engineering Simulation section specializes in the development and

140

Handbook of heat and mass transfer. Volume 2  

Science Conference Proceedings (OSTI)

This two-volume series, the work of more than 100 contributors, presents advanced topics in industrial heat and mass transfer operations and reactor design technology. Volume 2 emphasizes mass transfer and reactor design. Some of the contents discussed are: MASS TRANSFER PRINCIPLES - Effect of turbulence promoters on mass transfer. Mass transfer principles with homogeneous and heterogeneous reactions. Convective diffusion with reactions in a tube. Transient mass transfer onto small particles and drops. Modeling heat and mass transport in falling liquid films. Heat and mass transfer in film absorption. Multicomponent mass transfer: theory and applications. Diffusion limitation for reaction in porous catalysts. Kinetics and mechanisms of catalytic deactivation. DISTILLATION AND EXTRACTION - Generalized equations of state for process design. Mixture boiling. Estimating vapor pressure from normal boiling points of hydrocarbons. Estimating liquid and vapor molar fractions in distillation columns. Principles of multicomponent distillation. Generalized design methods for multicomponent distillation. Interfacial films in inorganic substances extraction. Liquid-liquid extraction in suspended slugs. MULTIPHASE REACTOR SYSTEMS - Reaction and mass transport in two-phase reactors. Mass transfer and kinetics in three-phase reactors. Estimating liquid film mass transfer coefficients in randomly packed columns. Designing packed tower wet scrubbers - emphasis on nitrogen oxides. Gas absorption in aerated mixers. Axial dispersion and heat transfer in gas-liquid bubble columns. Operation and design of trickle-bed reactors.

Cheremisinoff, N.P.

1986-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Passive heat transfer means for nuclear reactors  

DOE Patents (OSTI)

An improved passive cooling arrangement is disclosed for maintaining adjacent or related components of a nuclear reactor within specified temperature differences. Specifically, heat pipes are operatively interposed between the components, with the vaporizing section of the heat pipe proximate the hot component operable to cool it and the primary condensing section of the heat pipe proximate the other and cooler component operable to heat it. Each heat pipe further has a secondary condensing section that is located outwardly beyond the reactor confinement and in a secondary heat sink, such as air ambient the containment, that is cooler than the other reactor component. Means such as shrouding normally isolated the secondary condensing section from effective heat transfer with the heat sink, but a sensor responds to overheat conditions of the reactor to open the shrouding, which thereby increases the cooling capacity of the heat pipe. By having many such heat pipes, an emergency passive cooling system is defined that is operative without electrical power.

Burelbach, James P. (Glen Ellyn, IL)

1984-01-01T23:59:59.000Z

142

Heat transfer pathways in underfloor air distribution (UFAD) systems  

E-Print Network (OSTI)

permission. QC-06-053 Heat Transfer Pathways in Underfloorchange the dynamics of heat transfer within a room as wellchange the dynamics of heat transfer within a room as well

Bauman, F.; Jin, H.; Webster, T.

2006-01-01T23:59:59.000Z

143

AN EXPERIMENTAL AND THEORETICAL STUDY OF HEAT TRANSFER WITH COMBUSTION  

E-Print Network (OSTI)

Figure 7.6. Thin film heat transfer gauge. I I il j i II· Figure 2. 2. Thin 1m heat transfer gauge. 'l' :i t jt IIIII. MEASUREMENTS AND HEAT TRANSFER IN THE SOLID Experiments

Heperkan, Hasan A.

2013-01-01T23:59:59.000Z

144

Clean Boiler Waterside Heat Transfer Surfaces  

SciTech Connect

This revised ITP tip sheet on cleaning boiler water-side heat transfer surfaces provides how-to advice for improving industrial steam systems using low-cost, proven practices and technologies.

2006-01-01T23:59:59.000Z

145

Nonequilibrium Electromagnetic Fluctuations: Heat Transfer and Interactions  

E-Print Network (OSTI)

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in nonequilibrium cases where each body, and the ...

Kruger, Matthias

146

Daytime heat transfer processes over mountainous terrain  

Science Conference Proceedings (OSTI)

The daytime heat transfer mechanisms over mountainous terrain are investigated by means of large-eddy simulations over idealized valleys. Two- and three-dimensional topographies, corresponding to infinite and finite valleys, are used in order to ...

Juerg Schmidli

147

Scalable photon monte carlo algorithms and software for the solution of radiative heat transfer problems  

Science Conference Proceedings (OSTI)

Radiative heat transfer plays a central role in many combustion and engineering applications. Because of its highly nonlinear and nonlocal nature, the computational cost can be extremely high to model radiative heat transfer effects accurately. In this ...

Ivana Veljkovic; Paul E. Plassmann

2005-09-01T23:59:59.000Z

148

NEWTON: Greenhouse Gas and Heat Transfer  

NLE Websites -- All DOE Office Websites (Extended Search)

Greenhouse Gas and Heat Transfer Greenhouse Gas and Heat Transfer Name: Robert Status: teacher Grade: 9-12 Location: AK Country: USA Date: Summer 2013 Question: It would appear from a superficial reading that heat flows out of a greenhouse gas more slowly than heat flows into the same gas. This has to be an incorrect interpretation. It seems more likely that molecules with high heat capacities resist heat transfer-both into and out of such a molecular system. At a molecular level how does heat move out of a hot greenhouse gas? I have seen plots of Cv vs Tempt which indicates that heat moves from translational modes of motion-into rotational modes and finally into modes of vibration. The energy spacing of vibrations is generally grater that rotation which are greater than translation. Could it be that it is this quantization of the energy levels and the difference in energy between such quantum states that is the source of the resistance to heat flow or transfer?

149

Summary of the Models and Methods for the FEHM Application-A Finite-Element Heat- and Mass-Transfer Code  

DOE Green Energy (OSTI)

The mathematical models and numerical methods employed by the FEHM application, a finite-element heat- and mass-transfer computer code that can simulate nonisothermal multiphase multi-component flow in porous media, are described. The use of this code is applicable to natural-state studies of geothermal systems and groundwater flow. A primary use of the FEHM application will be to assist in the understanding of flow fields and mass transport in the saturated and unsaturated zones below the proposed Yucca Mountain nuclear waste repository in Nevada. The component models of FEHM are discussed. The first major component, Flow- and Energy-Transport Equations, deals with heat conduction; heat and mass transfer with pressure- and temperature-dependent properties, relative permeabilities and capillary pressures; isothermal air-water transport; and heat and mass transfer with noncondensible gas. The second component, Dual-Porosity and Double-Porosity/Double-Permeability Formulation, is designed for problems dominated by fracture flow. Another component, The Solute-Transport Models, includes both a reactive-transport model that simulates transport of multiple solutes with chemical reaction and a particle-tracking model. Finally, the component, Constitutive Relationships, deals with pressure- and temperature-dependent fluid/air/gas properties, relative permeabilities and capillary pressures, stress dependencies, and reactive and sorbing solutes. Each of these components is discussed in detail, including purpose, assumptions and limitations, derivation, applications, numerical method type, derivation of numerical model, location in the FEHM code flow, numerical stability and accuracy, and alternative approaches to modeling the component.

George A. Zyvoloski; Bruce A. Robinson; Zora V. Dash; Lynn L. Trease

1997-07-01T23:59:59.000Z

150

Aerodynamic Losses and Heat Transfer in a Blade Cascade with...  

NLE Websites -- All DOE Office Websites (Extended Search)

Aerodynamic Losses and Heat Transfer in a Aerodynamic Losses and Heat Transfer in a Blade Cascade with 3 Blade Cascade with 3 - - D D Endwall Endwall Contouring Contouring...

151

Experimental study on turbulent natural convection heat transfer in ...  

Science Conference Proceedings (OSTI)

Feb 16, 2010 ... ments are conducted to investigate flow and heat transfer ... turbulent region, the heat transfer deterioration occurs for a bubble flow rate Q = 33 ...

152

Heat transfer via dropwise condensation on hydrophobic microstructured surfaces.  

E-Print Network (OSTI)

??Dropwise condensation has the potential to greatly increase heat transfer rates. Heat transfer coefficients by dropwise condensation and film condensation on microstructured silicon chips were… (more)

Ruleman, Karlen E. (Karlen Elizabeth)

2009-01-01T23:59:59.000Z

153

Characterization and Development of Advanced Heat Transfer Technologies (Presentation)  

DOE Green Energy (OSTI)

Advancing heat transfer technologies is a critical factor in power electronics equipment. NREL aims to characterize and develop advanced heat transfer technologies.

Abraham, T.

2007-11-08T23:59:59.000Z

154

Heat transfer in excimer laser melting of thin polysilicon layers  

NLE Websites -- All DOE Office Websites (Extended Search)

Heat transfer in excimer laser melting of thin polysilicon layers Title Heat transfer in excimer laser melting of thin polysilicon layers Publication Type Journal Article Year of...

155

Literature survey of heat transfer enhancement techniques in refrigeration applications  

Science Conference Proceedings (OSTI)

A survey has been performed of the technical and patent literature on enhanced heat transfer of refrigerants in pool boiling, forced convection evaporation, and condensation. Extensive bibliographies of the technical literature and patents are given. Many passive and active techniques were examined for pure refrigerants, refrigerant-oil mixtures, and refrigerant mixtures. The citations were categorized according to enhancement technique, heat transfer mode, and tube or shell side focus. The effects of the enhancement techniques relative to smooth and/or pure refrigerants were illustrated through the discussion of selected papers. Patented enhancement techniques also are discussed. Enhanced heat transfer has demonstrated significant improvements in performance in many refrigerant applications. However, refrigerant mixtures and refrigerant-oil mixtures have not been studied extensively; no research has been performed with enhanced refrigerant mixtures with oil. Most studies have been of the parametric type; there has been inadequate examination of the fundamental processes governing enhanced refrigerant heat transfer, but some modeling is being done and correlations developed. It is clear that an enhancement technique must be optimized for the refrigerant and operating condition. Fundamental processes governing the heat transfer must be examined if models for enhancement techniques are to be developed; these models could provide the method to optimize a surface. Refrigerant mixtures, with and without oil present, must be studied with enhancement devices; there is too little known to be able to estimate the effects of mixtures (particularly NARMs) with enhanced heat transfer. Other conclusions and recommendations are offered.

Jensen, M.K.; Shome, B. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

1994-05-01T23:59:59.000Z

156

FILM COOLING CALCULATIONS WITH AN ITERATIVE CONJUGATE HEAT TRANSFER APPROACH USING EMPIRICAL HEAT TRANSFER COEFFICIENT CORRECTIONS.  

E-Print Network (OSTI)

??An iterative conjugate heat transfer technique was developed and automated to predict the temperatures on film cooled surfaces such as flat plates and turbine blades.… (more)

Dhiman, Sushant

2010-01-01T23:59:59.000Z

157

Nonequilibrium Electromagnetic Fluctuations: Heat Transfer and Interactions  

Science Conference Proceedings (OSTI)

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in nonequilibrium cases where each body, and the environment, is at a different temperature. The formalism tracks the radiation from each body and its scatterings by the other objects. We discuss the radiation from a cylinder, emphasizing its polarized nature, and obtain the heat transfer between a sphere and a plate, demonstrating the validity of proximity transfer approximation at close separations and arbitrary temperatures.

Krueger, Matthias; Kardar, Mehran [Massachusetts Institute of Technology, Department of Physics, Cambridge, Massachusetts 02139 (United States); Emig, Thorsten [Laboratoire de Physique Theorique et Modeles Statistiques, CNRS UMR 8626, Ba circumflex timent 100, Universite Paris-Sud, 91405 Orsay cedex (France)

2011-05-27T23:59:59.000Z

158

Heat and mass transfer analysis of a desiccant dehumidifier matrix  

DOE Green Energy (OSTI)

This report documents the SERI Single-Blow Test Facility's design, fabrication, and testing for characterizing desiccant dehumidifiers for solar cooling applications. The first test article, a silica-gel parallel-plate dehumidifier with highly uniform passages, was designed and fabricated. Transient heat and mass transfer data and pressure drop data across the dehumidifier were obtained. Available heat and mass transfer models were extended to the parallel-place geometry, and the experimental data were compared with model predictions. Pressure drop measurements were also compared with model predictions of the fully developed laminar flow theory. The comparisons between the lumped-capacitance model and the experimental data were satisfactory. The pressure drop data compared satisfactorily with the theory (within 15%). A solid-side resistance model that is more detailed and does not assume symmetrical diffusion in particles was recommended for performance. This study has increased our understanding of the heat and mass transfer in silica gel parallel-plate dehumidifiers.

Pesaran, A.A.

1986-07-01T23:59:59.000Z

159

Handbook of heat and mass transfer. Volume 1  

Science Conference Proceedings (OSTI)

This two-volume series, the work of more than 100 contributors, presents advanced topics in industrial heat and mass transfer operations and reactor design technology. Volume 1 emphasizes heat transfer operations. The contents are: Fundamentsls of momentum and heat transfer. Scaling in laminar and turbulent heat and mass transfer. Heat flux in the Benar-Rayleigh problem. Hydrodynamics of free liquid jets and their influence on heat transfer. Natural convection heat transfer to power law fluids. Natural convection in evaporating droplets. Principles of heat and mass transfer with liquid evaporation. Bubble nucleation, growth, and departure in boiling heat transfer. Forced convection boiling in uniformly heated channels. Transient boiling heat transfer under forced convection. Prediction of heat transfer during forced convection subcooled boiling. Liquid metal heat transfer in turbulent pipe flows. Mixed convection in buoyant plumes. Nucleation and growth in the diffusion cloud chamber. Convective and radiative heat transfer of flowing gaseous-solid suspensions. Heat transfer in gas-solid fluidized beds. Gas convection and unsteady conduction in fluid bed heat transfer. Heat transfer between tubes and gas-solid fluid beds. Periodic heat transfer through inhomogeneous layers.

Cheremisinoff, N.P.

1986-01-01T23:59:59.000Z

160

Electrically heated liquid tank employing heat pipe heat transfer means  

SciTech Connect

The heating apparatus for applying heat to the interior of a chamber includes a modular, removable, electrical, heat-producing unit and a heat pipe mountable in a wall of the chamber with one end of the pipe arranged to receive heat from the electrical heat producing unit exterior of the housing and with another end of the pipe constructed and arranged to apply heat to the medium within the chamber. The heat pipe has high conductivity with a low temperature differential between the ends thereof and the heat producing unit includes an electric coil positioned about and removably secured to the one end of the heat pipe. The electric coil is embedded in a high thermal conducitivity, low electrical conductivity filler material which is surrounded by a low thermal conductivity insulating jacket and which is received around a metal core member which is removably secured to the one end of the heat pipe.

Shutt, J.R.

1978-12-26T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Numerical and experimental validation of heat and mass transfer during heat treatment of wood  

Science Conference Proceedings (OSTI)

In the current work, the three-dimensional Navier-Stokes equations along with the energy and concentration equations for the fluid coupled with the energy and mass conservation equations for the solid (wood) are solved to study the transient heat and ... Keywords: Luikov's model, conjugate problem, heat and mass transfer, high-temperature wood treatment, mathematical modeling, validation

R. Younsi; D. Kocaefe; S. Poncsak; T. Junjun

2007-05-01T23:59:59.000Z

162

Efficient numerical modeling of borehole heat exchangers  

Science Conference Proceedings (OSTI)

This paper presents a finite element modeling technique for double U-tube borehole heat exchangers (BHE) and the surrounding soil mass. Focus is placed on presenting numerical analyses describing the capability of a BHE model, previously reported, to ... Keywords: BHE, Geothermal heat pumps, Geothermic, Heat transfer, Space heating

R. Al-Khoury; T. Kölbel; R. Schramedei

2010-10-01T23:59:59.000Z

163

Heat Transfer Enhancement for Finned-Tube Heat Exchangers with Vortex Generators: Experimental and Numerical Results  

Science Conference Proceedings (OSTI)

A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.

O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert

2002-08-01T23:59:59.000Z

164

A composite grid solver for conjugate heat transfer in fluid-structure systems  

Science Conference Proceedings (OSTI)

We describe a numerical method for modeling temperature-dependent fluid flow coupled to heat transfer in solids. This approach to conjugate heat transfer can be used to compute transient and steady state solutions to a wide range of fluid-solid systems ... Keywords: Conjugate heat transfer, Incompressible flow, Multi-domain solvers, Numerical methods, Overlapping grids

William D. Henshaw; Kyle K. Chand

2009-06-01T23:59:59.000Z

165

Numerical investigation of heat transfer enhancement by carbon nano fibers deposited on a flat plate  

Science Conference Proceedings (OSTI)

Numerical simulations of flow and heat transfer have been performed for flow over a plate surface covered with carbon nano fibers (CNFs). The CNFs influence on fluid flow and heat transfer has been investigated. Firstly, a stochastic model for CNFs deposition ... Keywords: Carbon nano fibers, Heat transfer, Lattice Boltzmann method

Nikola Pelevic; Theo Van Der Meer

2013-03-01T23:59:59.000Z

166

Heat transfer 1990. Proceedings of the ninth international heat transfer conference  

Science Conference Proceedings (OSTI)

This book contains the proceedings of the Ninth International Heat Transfer Conference. Included in Volume 6 are the following chapters: Local void fraction measurements in finned tube bundles, Unsteady heat and mass transfer in low two-phase flows and The effect of physical properties on drop size in annular flow.

Hetsroni, G.

1990-01-01T23:59:59.000Z

167

Radiative Heat Transfer between Neighboring Particles  

E-Print Network (OSTI)

The near-field interaction between two neighboring particles is known to produce enhanced radiative heat transfer. We advance in the understanding of this phenomenon by including the full electromagnetic particle response, heat exchange with the environment, and important radiative corrections both in the distance dependence of the fields and in the particle absorption coefficients. We find that crossed terms of electric and magnetic interactions dominate the transfer rate between gold and SiC particles, whereas radiative corrections reduce it by several orders of magnitude even at small separations. Radiation away from the dimer can be strongly suppressed or enhanced at low and high temperatures, respectively. These effects must be taken into account for an accurate description of radiative heat transfer in nanostructured environments.

Alejandro Manjavacas; F. Javier Garcia de Abajo

2012-01-26T23:59:59.000Z

168

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

heat flow in porous media, heat pipe, reservoir simulation,and vapor often leads to “heat-pipe” conditions, the steadytwo-phase zone, is the heat-pipe (i.e. , a zone of constant

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

169

Handbook of numerical heat transfer  

Science Conference Proceedings (OSTI)

A comprehensive presentation is given of virtually all numerical methods that are suitable for the analysis of the various heat transverse and fluid flow problems that occur in research, practice, and university instruction. After reviewing basic methodologies, the following topics are covered: finite difference and finite element methods for parabolic, elliptic, and hyperbolic systems; a comparative appraisal of finite difference versus finite element methods; integral and integrodifferential systems; perturbation methods; Monte Carlo methods; finite analytic methods; moving boundary problems; inverse problems; graphical display methods; grid generation methods; and programing methods for supercomputers.

Minkowycz, W.J.; Sparrow, E.M.; Schneider, G.E.; Pletcher, R.H.

1988-01-01T23:59:59.000Z

170

Splice connector with internal heat transfer jacket  

DOE Patents (OSTI)

A heat transfer jacket is placed over the terminal portions of the conductors of a pair of high voltage cables which are connected in a splice connection wherein a housing surrounds the connected conductor portions, the heat transfer jacket extending longitudinally between the confronting ends of a pair of adaptor sleeves placed upon the insulation of the cables to engage and locate the adaptor sleeves relative to one another, and laterally between the conductors and the housing to provide a path of relatively high thermal conductivity between the connected conductor portions and the housing.

Silva, Frank A. (Basking Ridge, NJ); Mayer, Robert W. (Hackettstown, NJ)

1977-01-01T23:59:59.000Z

171

Nanoscale Heat Transfer: from Computation to Experiment  

E-Print Network (OSTI)

Heat transfer can differ distinctly at the nanoscale from that at the macroscale. Recent advancement in computational and experimental techniques has enabled a large number of interesting observations and understanding of heat transfer processes at the nanoscale. In this review, we will first discuss recent advances in computational and experimental methods used in nanoscale thermal transport studies, followed by reviews of novel thermal transport phenomena at the nanoscale observed in both computational and experimental studies, and discussion on current understanding of these novel phenomena. Our perspectives on challenges and opportunities on computational and experimental methods are also presented.

Luo, Tengfei

2013-01-01T23:59:59.000Z

172

Curvature dependence of the interfacial heat and mass transfer coefficients  

E-Print Network (OSTI)

Nucleation is often accompanied by heat transfer between the surroundings and a nucleus of a new phase. The interface between two phases gives an additional resistance to this transfer. For small nuclei the interfacial curvature is high, which affects not only equilibrium quantities such as surface tension, but also the transport properties. In particular, high curvature affects the interfacial resistance to heat and mass transfer. We develop a framework for determining the curvature dependence of the interfacial heat and mass transfer resistances. We determine the interfacial resistances as a function of a curvature. The analysis is performed for a bubble of a one-component fluid and may be extended to various nuclei of multicomponent systems. The curvature dependence of the interfacial resistances is important in modeling transport processes in multiphase systems.

K. S. Glavatskiy; D. Bedeaux

2013-10-11T23:59:59.000Z

173

Modeling the heat and mass transfers in temperature-swing adsorption of volatile organic compounds onto activated carbons  

Science Conference Proceedings (OSTI)

A theoretical model was built to simulate the adsorption of volatile organic compounds (VOCs) onto activated carbons in a fixed bed. This model was validated on a set of experimental data obtained for the adsorption of acetone, ethyl formate, and dichloromethane onto five commercial activated carbons. The influence of operating conditions was modeled with various VOC contents at the inlet of the adsorber and superficial velocities of the gas-phase from 0.14 to 0.28 m.s{sup -1}. Breakthrough times and maximum temperature rises were computed with a coefficient of determination of 0.988 and 0.901, respectively. The simulation was then extended to the adsorption of mixtures of VOCs. From the comparison of simulation and experimental results, the advantage of accounting for dispersions of heat and mass is shown and the importance in taking into account the temperature effect on the equilibrium data is demonstrated. 29 refs., 6 figs., 1 tab.

Sylvain Giraudet; Pascaline Pre; Pierre Le Cloirec [Ecole des Mines de Nantes, Nantes (France)

2009-02-15T23:59:59.000Z

174

Heat and mass transfer in porous media  

DOE Green Energy (OSTI)

Field test data on the OOSI MR3 experiments are used as a basis for exhibiting the computational capabilities of the WAFE computer code, which is a generalized tool for the analysis of heat and mass transfer in multi-dimensional domains of porous geothermal materials.

Cook, T.L.; Harlow, F.H.; Travis, B.J.; Bartel, T.J.; Tyner, C.E.

1981-01-01T23:59:59.000Z

175

FEHM: finite element heat and mass transfer code  

DOE Green Energy (OSTI)

The finite element heat and mass (FEHM) transfer code is a computer code developed to simulate geothermal and hot dry rock reservoirs. It is also applicable to natural-state studies of geothermal systems and ground-water flow. It solves the equations of heat and mass transfer for multiphase flow in porous and permeable media using the finite element method. The code also has provisions for a noncoupled tracer; that is, the tracer solutions do not affect the heat and mass transfer solutions. It can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model, the numerical solution procedure, and model verification and validation are provided in this report. A user's guide and sample problems are included in the appendices. 17 refs., 10 figs., 4 tabs.

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1988-03-01T23:59:59.000Z

176

Cooperative heat transfer and ground coupled storage system  

DOE Patents (OSTI)

A cooperative heat transfer and ground coupled storage system wherein collected solar heat energy is ground stored and permitted to radiate into the adjacent ground for storage therein over an extended period of time when such heat energy is seasonally maximally available. Thereafter, when said heat energy is seasonally minimally available and has propagated through the adjacent ground a substantial distance, the stored heat energy may be retrieved by a circumferentially arranged heat transfer means having a high rate of heat transfer.

Metz, Philip D. (Rocky Point, NY)

1982-01-01T23:59:59.000Z

177

heat transfer | OpenEI Community  

Open Energy Info (EERE)

85 85 Varnish cache server Home Groups Community Central Green Button Applications Developer Utility Rate FRED: FRee Energy Database More Public Groups Private Groups Features Groups Blog posts Content Stream Documents Discussions Polls Q & A Events Notices My stuff Energy blogs 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 2142229585 Varnish cache server heat transfer Home Dc's picture Submitted by Dc(15) Member 15 November, 2013 - 13:26 Living Walls ancient building system architect biomimicry building technology cooling cu daylight design problem energy use engineer fred andreas geothermal green building heat transfer heating living walls metabolic adjustment net zero pre-electricity Renewable Energy Solar university of colorado utility grid Wind

178

Advanced Heat Transfer and Thermal Storage Fluids  

DOE Green Energy (OSTI)

The design of the next generation solar parabolic trough systems for power production will require the development of new thermal energy storage options with improved economics or operational characteristics. Current heat-transfer fluids such as VP-1?, which consists of a eutectic mixture of biphenyl and diphenyl oxide, allow a maximum operating temperature of ca. 300 C, a limit above which the vapor pressure would become too high and would require pressure-rated tanks. The use of VP-1? also suffers from a freezing point around 13 C that requires heating during cold periods. One of the goals for future trough systems is the use of heat-transfer fluids that can act as thermal storage media and that allow operating temperatures around 425 C combined with lower limits around 0 C. This paper presents an outline of our latest approach toward the development of such thermal storage fluids.

Moens, L.; Blake, D.

2005-01-01T23:59:59.000Z

179

Modeling of coupled heat transfer and reactive transport processesin porous media: Application to seepage studies at Yucca Mountain, Nevada  

SciTech Connect

When hot radioactive waste is placed in subsurface tunnels, a series of complex changes occurs in the surrounding medium. The water in the pore space of the medium undergoes vaporization and boiling. Subsequently, vapor migrates out of the matrix pore space, moving away from the tunnel through the permeable fracture network. This migration is propelled by buoyancy, by the increased vapor pressure caused by heating and boiling, and through local convection. In cooler regions, the vapor condenses on fracture walls, where it drains through the fracture network. Slow imbibition of water thereafter leads to gradual rewetting of the rock matrix. These thermal and hydrological processes also bring about chemical changes in the medium. Amorphous silica precipitates from boiling and evaporation, and calcite from heating and CO2 volatilization. The precipitation of amorphous silica, and to a much lesser extent calcite, results in long-term permeability reduction. Evaporative concentration also results in the precipitation of gypsum (or anhydrite), halite, fluorite and other salts. These evaporative minerals eventually redissolve after the boiling period is over, however, their precipitation results in a significant temporary decrease in permeability. Reduction of permeability is also associated with changes in fracture capillary characteristics. In short, the coupled thermal-hydrological-chemical (THC) processes dynamically alter the hydrological properties of the rock. A model based on the TOUGHREACT reactive transport software is presented here to investigate the impact of THC processes on flow near an emplacement tunnel at Yucca Mountain, Nevada. We show how transient changes in hydrological properties caused by THC processes often lead to local flow channeling and saturation increases above the tunnel. For models that include only permeability changes to fractures, such local flow channeling may lead to seepage relative to models where THC effects are ignored. However, coupled THC seepage models that include both permeability and capillary changes to fractures may not show this additional seepage.

Mukhopadhyay, Sumit; Sonnenthal, Eric L.; Spycher, Nicolas

2007-01-15T23:59:59.000Z

180

Modeling of coupled heat transfer and reactive transport processesin porous media: Application to seepage studies at Yucca Mountain, Nevada  

SciTech Connect

When hot radioactive waste is placed in subsurface tunnels, a series of complex changes occurs in the surrounding medium. The water in the pore space of the medium undergoes vaporization and boiling. Subsequently, vapor migrates out of the matrix pore space, moving away from the tunnel through the permeable fracture network. This migration is propelled by buoyancy, by the increased vapor pressure caused by heating and boiling, and through local convection. In cooler regions, the vapor condenses on fracture walls, where it drains through the fracture network. Slow imbibition of water thereafter leads to gradual rewetting of the rock matrix. These thermal and hydrological processes also bring about chemical changes in the medium. Amorphous silica precipitates from boiling and evaporation, and calcite from heating and CO{sub 2} volatilization. The precipitation of amorphous silica, and to a much lesser extent calcite, results in long-term permeability reduction. Evaporative concentration also results in the precipitation of gypsum (or anhydrite), halite, fluorite and other salts. These evaporative minerals eventually redissolve after the boiling period is over, however, their precipitation results in a significant temporary decrease in permeability. Reduction of permeability is also associated with changes in fracture capillary characteristics. In short, the coupled thermal-hydrological-chemical (THC) processes dynamically alter the hydrological properties of the rock. A model based on the TOUGHREACT reactive transport software is presented here to investigate the impact of THC processes on flow near an emplacement tunnel at Yucca Mountain, Nevada. We show how transient changes in hydrological properties caused by THC processes often lead to local flow channeling and saturation increases above the tunnel. For models that include only permeability changes to fractures, such local flow channeling may lead to seepage relative to models where THC effects are ignored. However, coupled THC seepage models that include both permeability and capillary changes to fractures may not show this additional seepage.

Mukhopadhyay, S.; Sonnenthal, E.L.; Spycher, N.

2007-01-15T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Aspects of forced convective heat transfer in geothermal systems  

DOE Green Energy (OSTI)

A knowledge of convective heat transfer is essential to understanding geothermal systems and other systems of moving groundwater. A simple, kinematic approach toward convective heat transfer is taken here. Concern is not with the cause of the groundwater motion but only with the fact that the water is moving and transferring heat. The mathematical basis of convective heat transfer is the energy equation which is a statement of the first law of thermodynamics. The general solution of this equation for a specific model of groundwater flow has to be done numerically. The numerical algorithm used here employs a finite difference approximation to the energy equation that uses central differences for the heat conduction terms and one-sided differences for the heat convection terms. Gauss--Seidel iteration is then used to solve the finite difference equation at each node of a non-uniform mesh. The Monroe and Red Hill hot springs, a small hydrothermal system in central Utah, provide an example to illustrate the application of convective heat transfer theory to a geophysical problem. Two important conclusions regarding small geothermal systems follow immediately from the results of this application. First, the most rapid temperature rise in the convecting part of a geothermal system is near the surface. Below this initially rapid temperature increase the temperature increases very slowly, and thus temperatures extrapolated from shallow boreholes can be seriously in error. Second, the temperatures and heat flows observed at Monroe and Red Hill, and probably at many other small geothermal areas, can easily result from moderate vertical groundwater velocities in faults and fracture zones in an area of normal heat flow.

Kilty, K.; Chapman, D.S.; Mase, C.

1978-07-01T23:59:59.000Z

182

Heat Transfer between Graphene and Amorphous SiO2  

E-Print Network (OSTI)

We study the heat transfer between graphene and amorphous SiO2. We include both the heat transfer from the area of real contact, and between the surfaces in the non-contact region. We consider the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies, and the heat transfer by the gas in the non-contact region. We find that the dominant contribution to the heat transfer result from the area of real contact, and the calculated value of the heat transfer coefficient is in good agreement with the value deduced from experimental data.

B. N. J. Persson; H. Ueba

2010-07-22T23:59:59.000Z

183

Heat Transfer Analysis of Post-Weld Heat Treatment of Grade 91 Steel  

Science Conference Proceedings (OSTI)

The appropriate heat transfer coefficients are determined through the inverse heat conduction method utilizing ceramic heat blankets as well as a furnace as the ...

184

Thermal Hydraulic Optimization of Nuclear Systems [Heat Transfer and Fluid  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermal Hydraulic Thermal Hydraulic Optimization of Nuclear Systems Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Thermal Hydraulic Optimization of Nuclear Systems Accelerator Driven Test Facility Target Accelerator Driven Test Facility Target. Click on image to view larger

185

Underhood Thermal Management [Heat Transfer and Fluid Mechanics] - Nuclear  

NLE Websites -- All DOE Office Websites (Extended Search)

Underhood Thermal Underhood Thermal Management Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Underhood Thermal Management Hybrid Vehicle Underhood Thermal Analysis Hybrid Vehicle Underhood Thermal Analysis. Click on image to view larger image. In addition to nuclear system applications, the section applies its

186

Reversible limit of processes of heat transfer  

E-Print Network (OSTI)

We study a process of heat transfer between a body of heat capacity C(T) and a sequence of N heat reservoirs, with temperatures equally spaced between an initial temperature T_0 and a final temperature T_N. The body and the heat reservoirs are isolated from the rest of the universe, and the body is brought in thermal contact successively with reservoirs of increasing temperature. We determine the change of entropy of the composite thermodynamic system in the total process in which the temperature of the body changes from T_0 to T_N. We find that for large values of N the total change of entropy of the composite process is proportional to (T_N-T_0)/N, but eventually a non-monotonic behavior is found at small values of N.

Stilck, Jürgen F

2013-01-01T23:59:59.000Z

187

Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools  

E-Print Network (OSTI)

and spacer effects on window U- value. ASHRAE Transactions,Enermodal. (2001). Modelling Windows, Glass Doors and OtherA. (2001). Heat transfer in window frames with internal

Gustavsen, Arild

2009-01-01T23:59:59.000Z

188

SPECIAL HEAT TRANSFER PHENOMENA FOR SUPERCRITICAL FLUIDS  

SciTech Connect

Present-day knowledge concerning the molecular structure of supercritical fluids is briefly reviewed. It is shown that liquid-like and gas- like phases may coexist at supercritical pressures, although they may not be in equllibrium with each other. it is postulated that on the basis of the coexistence of these two phases a "boiling-like" phenomenon may provide the mechanism of heat transfer to supercritical fluids at high heat fluxes and certain other conditions. An unusual mode of heat transfer was actually observed at supercritical pressures during tests which produced the high heat fluxes and other conditions under which such "boiling" would be expected. The tests and the various conditions are briefly described. An emission of high-frequeney, high- intensity sounds usually accompanied these tests. It is shown that similar screaming sounds were heard during boiling at subcritical pressures, giving further support to the hypothesis that "boiling" may occur at supercritical pressures. A seeond possible explanation for the unusual mode of heat transfer is based on boundarylayer stability considerations. At high heat fluxes large density differences exist between the bulk of the fluid and the fluid in the boundary layer near the wall. A breakdown of the boundary layer may be caused by the build-up of ripples between its low-density fluid and the high-density bulk fluid, in a manner quite similar to the breaking of ocean waves at high wind velocities. It is pointed out that the density variation of supercritical fluide may be used to advantage by certrifuging boundary layers. (auth)

Goldmann, K.

1956-01-01T23:59:59.000Z

189

Optimization of Phase Change Heat Transfer in Biporous Media.  

E-Print Network (OSTI)

??As the heat transfer demands placed on small electronics devices increase, the demand for efficient evaporators for heat pipes and spreaders will increase in kind.… (more)

Reilly, Sean

2013-01-01T23:59:59.000Z

190

Simulation of a Heat Transfer in Porous Media  

E-Print Network (OSTI)

We are motivated to model a heat transfer to a multiple layer regime and their optimization for heat energy resources. Such a problem can be modeled by a porous media with different phases (liquid and solid). The idea arose of a geothermal energy reservoir which can be used by cities, e.g. Berlin. While hot ground areas are covered to most high populated cites, the energy resources are important and a shift to use such resources are enormous. We design a model of the heat transport via the flow of water through the heterogeneous layer of the underlying earth sediments. We discuss a multiple layer model, based on mobile and immobile zones. Such numerical simulations help to economize on expensive physical experiments and obtain control mechanisms for the delicate heating process.

Juergen Geiser

2012-05-11T23:59:59.000Z

191

FEHM (Finite Element Heat and Mass Transfer Code)  

NLE Websites -- All DOE Office Websites (Extended Search)

FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep...

192

Nanofluid heat transfer enhancement for nuclear reactor applications  

E-Print Network (OSTI)

Colloidal dispersions of nanoparticles are known as `nanofluids'. Such engineered fluids offer the potential for enhancing heat transfer, particularly boiling heat transfer, while avoiding the drawbacks (i.e., erosion, ...

Buongiorno, Jacopo

193

Heat Transfer in Projecting and Sloped Fenestration Products  

NLE Websites -- All DOE Office Websites (Extended Search)

Heat Transfer in Projecting and Sloped Fenestration Products Speaker(s): Dragan Charlie Curcija Date: May 26, 2010 - 12:00pm Location: 90-3122 The heat transfer performance of...

194

Heat transfer during film condensation of potassium vapor  

E-Print Network (OSTI)

The object of this work is to investigate theoretically and experimentally the following two phases of heat transfer during condensation of potassium vapore, a. Heat transfer during film condensation of pure saturated ...

Kroger, Detlev Gustav

1966-01-01T23:59:59.000Z

195

An experimental study of the flow and heat transfer between enhanced heat transfer plates for PHEs  

Science Conference Proceedings (OSTI)

The flow and heat transfer between inclined discrete rib plates for plate heat exchangers have been experimentally studied. Dye injection method is used to visualize the flow structures. The visualization results show that front vortex, rear vortex and main vortex are formed between the plates. The rib parameter influence is also studied using visualization method. The pressure drop and heat transfer between the inclined discrete rib plates as well as that between inclined continuous rib plates and smooth plates are also measured. The measured results show that the inclined discrete rib plate can enhanced heat transfer 20-25% at the same pumping power compared with the commonly used inclined continuous rib plates. (author)

Li, Xiao-wei [Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084 (China); Meng, Ji-an; Li, Zhi-xin [School of Aerospace, Tsinghua University, Beijing 100084 (China)

2010-11-15T23:59:59.000Z

196

Heat Transfer Fluids Containing Nanoparticles (08-066)  

The issue of heat transfer offers fertile ground for scientific exploration across many disciplines. Argonne researchers have discovered the potential ...

197

Handbook of heat transfer fundamentals (2nd edition)  

SciTech Connect

Recent advances in heat transfer are discussed, providing data and methodology to solve a wide range of heat transfer problems. The topics considered include: basic concepts of heat transfer, mathematical methods, thermophysical properties, conduction, numerical methods in heat transfer, natural convection, and internal duct flow and external flows in forced convection. Also addressed are: rarefied gases, electric and magnetic fields, condensation, boiling, two-phase flow, and radiation.

Rohsenow, W.M.; Hartnett, J.P.; Ganic, E.N.

1985-01-01T23:59:59.000Z

198

Handbook of heat and mass transfer. Volumes 1 and 2  

Science Conference Proceedings (OSTI)

This two-volume series presents advanced topics in industrial heat and mass transfer operations for reactor design technology.

Cheremisinoff, N.P.

1985-01-01T23:59:59.000Z

199

Molten Salt Heat Transfer Fluid (HTF) - Energy Innovation Portal  

Solar Thermal Industrial Technologies Energy Storage Molten Salt Heat Transfer Fluid (HTF) Sandia National Laboratories. Contact SNL About This ...

200

Heat Transfer Characteristics of Magnetite under Microwave Irradiation  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Materials Processing Fundamentals. Presentation Title, Heat Transfer ...

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Heat Transfer Operators Associated with Quantum Operations  

E-Print Network (OSTI)

Any quantum operation applied on a physical system is performed as a unitary transformation on a larger extended system. If the extension used is a heat bath in thermal equilibrium, the concomitant change in the state of the bath necessarily implies a heat exchange with it. The dependence of the average heat transferred to the bath on the initial state of the system can then be found from the expectation value of a hermitian operator, which is named as the heat transfer operator (HTO). The purpose of this article is the investigation of the relation between the HTOs and the associated quantum operations. Since, any given quantum operation on a system can be realized by different baths and unitaries, many different HTOs are possible for each quantum operation. On the other hand, there are also strong restrictions on the HTOs which arise from the unitarity of the transformations. The most important of these is the Landauer erasure principle. This article is concerned with the question of finding a complete set of restrictions on the HTOs that are associated with a given quantum operation. An answer to this question has been found only for a subset of quantum operations. For erasure operations, these characterizations are equivalent to the generalized Landauer erasure principle. For the case of generic quantum operations however, it appears that the HTOs obey further restrictions which cannot be obtained from the entropic restrictions of the generalized Landauer erasure principle.

Ç. Aksak; S. Turgut

2010-02-03T23:59:59.000Z

202

Heat transfer of finned tube bundles in crossflow  

SciTech Connect

This volume correlates findings on heat transfer and hydraulic drag of bundles of finned tubes in crossflow at Reynolds numbers from 10/sup 4/ to 10/sup 6/. These studies illustrate fin, local, and mean heat transfer coefficients; effects of geometric parameters of the fins; effect of tube location within the bundle on heat transfer and hydraulic drag; and resistance of finned tube bundles.

Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.

1988-01-01T23:59:59.000Z

203

DEVELOPING FLOW AND HEAT TRANSFER IN STRONGLY CURVED DUCTS OF RECTANGULAR CROSS-SECTION  

E-Print Network (OSTI)

Forced Convection Heat Transfer in Curved RectangularInfluence of Curvature on Heat Transfer to IncompressibleT. , "Forced Convective Heat Transfer in a Curved Channel

Yee, G.

2010-01-01T23:59:59.000Z

204

Heat Transfer Limitations in Hydrogen Production Via Steam Reformation: The Effect of Reactor Geometry  

E-Print Network (OSTI)

Ohsawa, Katsuyuki, “Heat Transfer Enhancement in Methanolsin the Catalyst Bed”, Heat Transfer-Asian Research, Vol.CA FUELCELL2006-97109 HEAT TRANSFER LIMITATIONS IN HYDROGEN

Vernon, David R.; Davieau, David D.; Dudgeon, Bryce A.; Erickson, Paul A.

2006-01-01T23:59:59.000Z

205

Exploring the Limits of Boiling and Evaporative Heat Transfer Using Micro/Nano Structures  

E-Print Network (OSTI)

and condensation processes in heat transfer equipment, 2ndand condensation processes in heat transfer equipment, in,the convection process, the heat transfer coefficient of

Lu, Ming-Chang

2010-01-01T23:59:59.000Z

206

Photovoltaic roof heat flux  

E-Print Network (OSTI)

and could the heat transfer processes be modeled to estimateindicating that the heat transfer processes were modeled w i

Samady, Mezhgan Frishta

2011-01-01T23:59:59.000Z

207

Estimates of Evapotranspiration with a One- and Two-Layer Model of Heat Transfer over Partial Canopy Cover  

Science Conference Proceedings (OSTI)

One of the applications of remotely sensed surface temperature is to determine the latent heat flux (LE) or evapotranspiration (ET) from held to regional scales. A common approach has been to use surface-air temperature differences in a bulk ...

William P. Kustas

1990-08-01T23:59:59.000Z

208

High Operating Temperature Liquid Metal Heat Transfer Fluids  

NLE Websites -- All DOE Office Websites (Extended Search)

Liquid Metal Liquid Metal Heat Transfer Fluids UCLA, UCB, Yale DE-EE0005941 | April 15, 2013 | Ju 1.1 Thermochemistry modeling * Continue CALPHAD based calculations to search for optimal ternary alloy compositions. * Initiate development of liquid density models. 1.2 Combinatorial synthesis and characterization * Pipe-Liquid interaction of compositional library * More alloys, alloy additions and effect on liquidus temperatures * Iteratively optimize the compositions. 1.3 Corrosion characterization and mitigation * Tune static corrosion testing systems for testing over an extended period of time. * Perform analysis of the micro mechanical testing on the oxide layers. 1.4 Heat transfer characterization and modeling * Complete the construction of the flow loop and perform experiments to measure

209

Integration of Heat Transfer, Stress, and Particle Trajectory Simulation  

Science Conference Proceedings (OSTI)

Calabazas Creek Research, Inc. developed and currently markets Beam Optics Analyzer (BOA) in the United States and abroad. BOA is a 3D, charged particle optics code that solves the electric and magnetic fields with and without the presence of particles. It includes automatic and adaptive meshing to resolve spatial scales ranging from a few millimeters to meters. It is fully integrated with CAD packages, such as SolidWorks, allowing seamless geometry updates. The code includes iterative procedures for optimization, including a fully functional, graphical user interface. Recently, time dependent, particle in cell capability was added, pushing particles synchronically under quasistatic electromagnetic fields to obtain particle bunching under RF conditions. A heat transfer solver was added during this Phase I program. Completed tasks include: (1) Added a 3D finite element heat transfer solver with adaptivity; (2) Determined the accuracy of the linear heat transfer field solver to provide the basis for development of higher order solvers in Phase II; (3) Provided more accurate and smoother power density fields; and (4) Defined the geometry using the same CAD model, while maintaining different meshes, and interfacing the power density field between the particle simulator and heat transfer solvers. These objectives were achieved using modern programming techniques and algorithms. All programming was in C++ and parallelization in OpenMP, utilizing state-of-the-art multi-core technology. Both x86 and x64 versions are supported. The GUI design and implementation used Microsoft Foundation Class.

Thuc Bui; Michael Read; Lawrence ives

2012-05-17T23:59:59.000Z

210

HEAT TRANSFER ANALYSIS FOR NUCLEAR WASTE SOLIDIFICATION CONTAINER  

SciTech Connect

The Nuclear Nonproliferation Programs Design Authority is in the design stage of the Waste Solidification Building (WSB) for the treatment and solidification of the radioactive liquid waste streams generated by the Pit Disassembly and Conversion Facility (PDCF) and Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF). The waste streams will be mixed with a cementitious dry mix in a 55-gallon waste container. Savannah River National Laboratory (SRNL) has been performing the testing and evaluations to support technical decisions for the WSB. Engineering Modeling & Simulation Group was requested to evaluate the thermal performance of the 55-gallon drum containing hydration heat source associated with the current baseline cement waste form. A transient axi-symmetric heat transfer model for the drum partially filled with waste form cement has been developed and heat transfer calculations performed for the baseline design configurations. For this case, 65 percent of the drum volume was assumed to be filled with the waste form, which has transient hydration heat source, as one of the baseline conditions. A series of modeling calculations has been performed using a computational heat transfer approach. The baseline modeling results show that the time to reach the maximum temperature of the 65 percent filled drum is about 32 hours when a 43 C initial cement temperature is assumed to be cooled by natural convection with 27 C external air. In addition, the results computed by the present model were compared with analytical solutions. The modeling results will be benchmarked against the prototypic test results. The verified model will be used for the evaluation of the thermal performance for the WSB drum. Detailed results and the cases considered in the calculations will be discussed here.

Lee, S.

2009-06-01T23:59:59.000Z

211

Heat Transfer Fluids for Solar Water Heating Systems | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems Heat Transfer Fluids for Solar Water Heating Systems May 16, 2013 - 3:02pm Addthis Illustration of a solar water heater. Illustration of a solar water heater. Heat-transfer fluids carry heat through solar collectors and a heat exchanger to the heat storage tanks in solar water heating systems. When selecting a heat-transfer fluid, you and your solar heating contractor should consider the following criteria: Coefficient of expansion - the fractional change in length (or sometimes in volume, when specified) of a material for a unit change in temperature Viscosity - resistance of a liquid to sheer forces (and hence to flow) Thermal capacity - the ability of matter to store heat Freezing point - the temperature below which a liquid turns into a

212

Heat Transfer Correlation for Finned Casks  

SciTech Connect

Design of finned casks for dissipation of heat from radioactive decay usually requires reliance on generalized correlations in the literature which do not necessarily apply to the specific cask design. A correlation was developed, based on temperature profile measurements, for the design of upright cylindrical casks with vertical fins for convective and radiant heat transfer to ambient air. Temperature data at various heat loads were obtained for two different cask sizes of the same basic design. Each cask is mounted on a steel pallet and contained within a steel mesh cage. The smaller cask, which has 23 fins, has been approved (DOT-SP-6321) for shipment of up to 1400 W (th), and approval is being obtained (AEC AL USA/9503 BLF) for shipment of up to 3500 W heat load in the larger, 60-fin cask. The applicable theoretical equations were fit to the temperature data for both casks by simply adjusting the value used for the number of fins. The resulting correlation provides a reliable method for interpolation and extrapolation and for design of similar finned casks.

Griffin, J. F.

1974-04-01T23:59:59.000Z

213

Heat Transfer Analysis of Asphalt Concrete Pavement Based on Snow Melting  

Science Conference Proceedings (OSTI)

On the basis of Wuhan district weather conditions of January 5, 2010, heat transfer mechanism of Beijing-Zhuhai Expressway Hubei section of asphalt concrete pavement based on snow melting is analyzed and the model of heat transmission is established. ... Keywords: asphalt concrete pavement, ground-source heat, pump, deicing and snow melting, heat flux

Yan-ping Tu; Jie Li; Chang-sheng Guan

2010-06-01T23:59:59.000Z

214

Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers  

E-Print Network (OSTI)

Effects of winglets to augment tube wall heat transfer in louvered fin heat exchangers Paul A Abstract The louvered fin heat exchanger, a type of compact heat exchanger, has been used heavily transfer along the tube wall of the compact heat exchanger through the use of winglets placed

Thole, Karen A.

215

CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER  

E-Print Network (OSTI)

1 CORRELATING EVAPORATION HEAT TRANSFER COEFFICIENT OF REFRIGERANT R-134a IN A PLATE HEAT EXCHANGER for evaporation heat transfer coefficient of refrigerant R-134a flowing in a plate heat exchanger. Correlation heat exchanger are found to result in large discrepancies with their own experimental data

Kandlikar, Satish

216

Combustion Simulations [Heat Transfer and Fluid Mechanics] - Nuclear  

NLE Websites -- All DOE Office Websites (Extended Search)

Combustion Simulations Combustion Simulations Capabilities Engineering Computation and Design Engineering and Structural Mechanics Systems/Component Design, Engineering and Drafting Heat Transfer and Fluid Mechanics Overview Thermal Hydraulic Optimization of Nuclear Systems Underhood Thermal Management Combustion Simulations Advanced Model and Methodology Development Multi-physics Reactor Performance and Safety Simulations Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Heat Transfer and Fluid Mechanics Bookmark and Share Combustion Simulations Density Distribution of Spray in Near-Injector Region Density Distribution of Spray in Near-Injector Region. Click on image to view larger image. Development of computer models based on Front-Tracking and

217

Characteristics of multimode heat transfer in a differentially-heated horizontal rectangular duct.  

E-Print Network (OSTI)

??This study presents the numerical analysis of steady laminar flow heat transfer in a horizontal rectangular duct with differential heating on the vertical walls. Three… (more)

Wangdhamkoom, Panitan

2007-01-01T23:59:59.000Z

218

Factors affecting oscillating motion and heat transfer in an oscillating heat pipe .  

E-Print Network (OSTI)

??As demand has grown for thermal management solutions, interest in passive heat transfer devices such as heat pipes has grown as well. In particular, oscillating… (more)

Smoot, Christopher

2013-01-01T23:59:59.000Z

219

Heat transfer assembly for a fluorescent lamp and fixture  

DOE Patents (OSTI)

In a lighting fixture including a lamp and a housing, a heat transfer structure is disclosed for reducing the minimum lamp wall temperature of a fluorescent light bulb. The heat transfer structure, constructed of thermally conductive material, extends from inside the housing to outside the housing, transferring heat energy generated from a fluorescent light bulb to outside the housing where the heat energy is dissipated to the ambient air outside the housing. Also disclosed is a method for reducing minimum lamp wall temperatures. Further disclosed is an improved lighting fixture including a lamp, a housing and the aforementioned heat transfer structure. 11 figs.

Siminovitch, M.J.; Rubenstein, F.M.; Whitman, R.E.

1992-12-29T23:59:59.000Z

220

Heat transfer assembly for a fluorescent lamp and fixture  

DOE Patents (OSTI)

In a lighting fixture including a lamp and a housing, a heat transfer structure is disclosed for reducing the minimum lamp wall temperature of a fluorescent light bulb. The heat transfer structure, constructed of thermally conductive material, extends from inside the housing to outside the housing, transferring heat energy generated from a fluorescent light bulb to outside the housing where the heat energy is dissipated to the ambient air outside the housing. Also disclosed is a method for reducing minimum lamp wall temperatures. Further disclosed is an improved lighting fixture including a lamp, a housing and the aforementioned heat transfer structure.

Siminovitch, Michael J. (Richmond, CA); Rubenstein, Francis M. (Berkeley, CA); Whitman, Richard E. (Richmond, CA)

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Heat transfer to impacting drops and post critical heat flux dispersed flow  

E-Print Network (OSTI)

Heat transfer to drops impacting on a hot surface is examined in context of dispersions of flowing, boiling fluids. The liquid contribution to heat transfer from a hot tube to a two-phase dispersion is formulated in terms ...

Kendall, Gail E.

1978-01-01T23:59:59.000Z

222

Influence of Infrared Radiation on Attic Heat Transfer  

E-Print Network (OSTI)

An experimental study concerned with different modes of heal transfer in fibrous and cellulose insulating material is presented. A series of experiments were conducted using an attic simulator to determine the effects of ventilation on attic heat transfer, and the effect of infrared radiation on the thermal conductivity of the insulation system and on attic heat transfer. All the tests were performed at steady state conditions by controlling the roof deck temperature. Calculations are performed for insulation thicknesses between 1 inch (2.54cm) and 6.0 inches (15.24cm) and roof deck temperatures between 145°F (62.78°C) and 100°F (36.78°C). The temperature profiles within the insulation were measured by placing thermocouples at various levels within the insulation. The profiles for the cellulose insulation are linear. The profiles within the glass fiber insulation are non-linear due to the effect of infrared radiation. Also heat fluxes were measured through different insulation thicknesses and for different roof temperatures. It was found that a radiant barrier such as aluminum foil can reduce the heat flux significantly. Experimental results were compared to a Three-Region approximate solution developed at Oak Ridge National Laboratories (ORNL). The model was in good agreement with experimental results.

Katipamula, S.; Turner, W. D.; Murphy, W. E.; O'Neal, D. L.

1985-01-01T23:59:59.000Z

223

A Mountain-Scale Thermal Hydrologic Model for Simulating Fluid Flow and Heat Transfer in Unsaturated Fractured Rock  

E-Print Network (OSTI)

Studies Using the Yucca Mountain Unsaturated Zone Model,Unsaturated Zone at Yucca Mountain, Nevada, to Thermal LoadUnsaturated Zone, Yucca Mountain, Nevada, Water-Resources

Wu, Yu-Shu; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, Gudmundur S.

2005-01-01T23:59:59.000Z

224

Effect of surface conditions on boiling heat transfer of refrigerants in shell-and-tube evaporators  

Science Conference Proceedings (OSTI)

Experimental results are presented for the boiling heat transfer performance of R 22 and R 717 on surfaces with porous metallized coatings. A calculational-theoretical model is given for predicting the heat transfer of refrigerants boiling on a bundle of finned tubes.

Danilova, G.N.; Dyundin, V.A.; Borishanskaya, A.V.; Soloviyov, A.G.; Vol'nykh, Y.A.; Kozyrev, A.A.

1990-01-01T23:59:59.000Z

225

Flexible profile approach to the conjugate heat transfer problem  

E-Print Network (OSTI)

The flexible profile approach proposed earlier to create CTM (compact or reduced order thermal models) is extended to cover the area of conjugate heat transfer. The flexible profile approach is a methodology that allows building a highly boundary conditions independent CTM, with any desired degree of accuracy, that may adequately replace detailed 3D models for the whole spectrum of applications in which the modeled object may be used. The extension to conjugate problems radically solves the problem of interfacing two different domains. Each domain, fluid or solid, can be "compacted" independently creating two CTM that can be joined together to produce reliable results for any arbitrary set of external boundary conditions.

M. -N. Sabry

2008-01-07T23:59:59.000Z

226

Heat Transfer Applications for the Stimulated Reservoir Volume  

E-Print Network (OSTI)

Multistage hydraulic fracturing of horizontal wells continues to be a major technological tool in the oil and gas industry. Creation of multiple transverse fractures in shale gas has enabled production from very low permeability. The strategy entails the development of a Stimulated Reservoir Volume (SRV), defined as the volume of reservoir, which is effectively stimulated to increase the well performance. An ideal model for a shale gas SRV is a rectangle of length equal to horizontal well length and width equal to twice the half length of the created hydraulic fractures. This project focused on using the Multistage Transverse Fractured Horizontal Wells (MTFHW) for two novel applications. The first application considers using the SRV of a shale gas well, after the gas production rate drops below the economic limit, for low grade geothermal heat extraction. Cold water is pumped into the fracture network through one horizontal well drilled at the fracture tips. Heat is transferred to the water through the fracture surface. The hot water is then recovered through a second horizontal well drilled at the other end of the fracture network. The basis of this concept is to use the already created stimulated reservoir volume for heat transfer purposes. This technique was applied to the SRV of Haynesville Shale and the results were discussed in light of the economics of the project. For the second application, we considered the use of a similarly created SRV for producing hydrocarbon products from oil shale. Thermal decomposition of kerogen to oil and gas requires heating the oil shale to 700 degrees F. High quality saturated steam generated using a small scale nuclear plant was used for heating the formation to the necessary temperature. Analytical and numerical models are developed for modeling heat transfer in a single fracture unit of MTFHW. These models suggest that successful reuse of Haynesville Shale gas production wells for low grade geothermal heat extraction and the project appears feasible both technically and economically. The economics of the project is greatly aided by eliminating well drilling and completion costs. The models also demonstrate the success of using MTFHW array for heating oil shale using SMR technology.

Thoram, Srikanth

2011-08-01T23:59:59.000Z

227

Mechanism and behavior of nucleate boiling heat transfer to the alkalai liquid metals  

E-Print Network (OSTI)

A model of boiling heat transfer to the alkali liquid metals is postulated from an examination of the events and phases of the nucleate boiling cycle. The model includes the important effect of microlayer evaporation which ...

Deane, Charles William

1969-01-01T23:59:59.000Z

228

Radiative Heat Transfer Analysis within Three-Dimensional Clouds Subjected to Solar and Sky Irradiation  

Science Conference Proceedings (OSTI)

A three-dimensional radiative heat transfer analysis of an arbitrary-shaped modeled cloud subjected to solar and sky irradiation has been performed. The Radiation Element Method by Ray Emission Model (REM2) was used for numerical simulation. ...

Toru Nishikawa; Shigenao Maruyama; Seigo Sakai

2004-12-01T23:59:59.000Z

229

HEAT TRANSFER AND TRITIUM PRODUCING SYSTEM  

DOE Patents (OSTI)

This invention related to a circulating lithium-containing blanket system in a neution source hav'ing a magnetic field associated therewith. The blanket serves simultaneously and efficiently as a heat transfer mediunm and as a source of tritium. The blanket is composed of a lithium-6-enriched fused salt selected from the group consisting of lithium nitrite, lithium nitrate, a mixture of said salts, a mixture of each of said salts with lithium oxide, and a mixture of said salts with each other and with lithium oxide. The moderator, which is contained within the blanket in a separate conduit, can be water. A stellarator is one of the neutron sources which can be used in this invention. (AEC)

Johnson, E.F.

1962-06-01T23:59:59.000Z

230

Simulation of heat transfer in the unsaturated zone  

SciTech Connect

Heat transfer can play an important role in fluid flow near the emplacement site of high-level nuclear waste. The effects on far- field flow can be important in understanding net moisture fluxes above the repository zone. The convection in the unsaturated zone at the Yucca Mountain site was responsible for this movement. If this is so, then the convection could provide a mechanism for drying the rock above the repository zone and thus provide a buffer for heavy rainfall events. In addition, the convection would increase the movement of gaseous radionuclides such as {sup 14}CO{sub 2}, tritiated water vapor, and {sup 129}I (Weeks, 1987). Because of the complexity of the problem, numerical models were required to calculate gas flow and vapor transport at the site. Kipp previously modeled this problem using the code HST3D. This code represents the flow of a single-phase fluid with both heat- and mass-transfer effects included. Water density and partial pressure effects are accounted for by the virtual temperature method. In this paper, the problem was simulated using the code FEHMN, a finite-element heat- and mass-transfer code being developed for the Yucca Mountain Project. The work described in this paper was done in preparation of the upcoming problem to be formulated for the Performance Assessment Calculation Exercise. 5 refs., 9 figs., 1 tab.

Zyvoloski, G.

1990-02-01T23:59:59.000Z

231

Heat transfer in bundles of finned tubes in crossflow  

SciTech Connect

This book provides correlations of heat transfer and hydraulic data for bundles of finned tubes in crossflow at high Reynolds numbers. Results of studies of the effectiveness of the fin, local, and mean heat transfer coefficients are presented. The effect of geometric parameters of the fins and of the location of tubes in the bundle on heat transfer and hydraulic drag are described. The resistance of the finned tube bundles under study and other factors are examined.

Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.; Hewitt, G.F.

1986-01-01T23:59:59.000Z

232

ETTM - Heat Transfer Calculations Version 1.0  

Science Conference Proceedings (OSTI)

ETTM Heat Transfer Calculations is a computer based training module that allows users to access training when desired and review it at their own pace. It provides graphics and limited interactive features to enhance learning. This module reviews the basic engineering principles used to calculate heat transfer and how to apply these principles to typical nuclear plant applications. The calculation of heat transfer in plant systems is an important element of many engineering calculations. Students should r...

2010-09-27T23:59:59.000Z

233

Study on the Interfacial Heat Transfer Coefficient of High Pressure ...  

Science Conference Proceedings (OSTI)

The heat transfer behavior between an AM60B alloy casting and die during .... for Spent Nuclear Fuel and Measuring the Composition of Molten Salt by Using ...

234

A versatile procedure for calculating heat transfer through windows  

SciTech Connect

Advances in window technologies and the desire to standardize the reporting of standard window heat transfer indices have necessitated the development of a comprehensive analytical procedure for calculating heat transfer through windows. This paper shows how complete window heat transfer can be considered as the area-weighted sum of the three window component areas: the center-of-glass area, the edge-of-glass area, and the frame area. Algorithms for calculating heat transfer through each of these areas and for combining these to calculate total window indices are presented. 36 refs., 5 figs., 6 tabs.

Arasteh, D.K.; Reilly, M.S.; Rubin, M.D.

1989-05-01T23:59:59.000Z

235

Impact of Heat Transfer Media on Materials for Concentrated Solar ...  

Science Conference Proceedings (OSTI)

Presentation Title, Impact of Heat Transfer Media on Materials for Concentrated Solar Power. Author(s), Dane Wilson. On-Site Speaker (Planned), Dane Wilson.

236

Estimation of Heat Transfer Coefficient in Squeeze Casting of ...  

Science Conference Proceedings (OSTI)

The casting-die interfacial heat transfer coefficient(IHTC) in 5-step casting was .... from First-Principles: Solid-Solution Strengthening, Softening, and Cross-Slip.

237

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

NLE Websites -- All DOE Office Websites (Extended Search)

Thermophysical Properties In our Thermal Storage Materials Laboratory, we use a variety of instruments to measure the thermophysical properties of heat transfer fluids and storage...

238

Characterization and Development of Advanced Heat Transfer Technologies (Presentation)  

DOE Green Energy (OSTI)

This presentation gives an overview of the status and FY09 accomplishments for the NREL thermal management research project 'Characterization and Development of Advanced Heat Transfer Technologies'.

Kelly, K.

2009-05-01T23:59:59.000Z

239

Determination of Heat Transfer Coefficient Distribution at Part ...  

Science Conference Proceedings (OSTI)

... of oil flow on the heat transfer coefficient (HTC) distribution at the gear surface. ... Multiphase Flow in a Steelmaking Converter Using an Unconventional Lance.

240

Handbook of thermodynamics, heat transfer and fluid flow  

E-Print Network (OSTI)

9 Nov 2010 ... Handbook of thermodynamics, heat transfer and fluid flow | JUNE 1992 | 3 Volume | U.S. Department of Energy FSC-6910 Washington, D.C. ...

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Applications of COMSOL Multiphysics Software to Heat Transfer Processes.  

E-Print Network (OSTI)

??This thesis used the study of Heat Transfer and COMSOL Multiphysics software as a reference which was made for the purpose of future education in… (more)

Xiong, Wei

2010-01-01T23:59:59.000Z

242

Microcellular Biomorphous Ceramics for Two Phase Heat Transfer ...  

Science Conference Proceedings (OSTI)

Heat transfer behavior of microcellular biomorphous Al2O3 was evaluated by a fluid-dynamic approach and tested in a planar capillary evaporator.

243

NREL Improves Window Heat Transfer Calculations (Fact Sheet)...  

NLE Websites -- All DOE Office Websites (Extended Search)

and interior radiation. The most significant errors were found in detailed window heat transfer algorithms due to implementation problems. The results show a decrease in...

244

Heat Transfer through Materials: Application to Silica Aerogels...  

NLE Websites -- All DOE Office Websites (Extended Search)

Heat Transfer through Materials: Application to Silica Aerogels and Building Envelopes Speaker(s): Brangre Lartigue Date: December 19, 2005 - 12:00pm Location: Bldg. 90 After...

245

Phase Change Materials for Enhancing Heat Transfer in Thermal ...  

Science Conference Proceedings (OSTI)

One of the main issues with using phase change materials is that solidification often reduces total heat transfer, reducing the efficiency of the storage system.

246

Rotating Heat Transfer in High Aspect Ratio Rectangular Cooling...  

NLE Websites -- All DOE Office Websites (Extended Search)

Reynolds Number (Nu Nu o ) (f f o ) 24% Increase in Cooling Performance Rotating Heat Transfer in High Aspect Ratio Rectangular Cooling Passages with Shaped Turbulators...

247

Enhanced boiling heat transfer by submerged, vibration induced jets .  

E-Print Network (OSTI)

??In this analysis, the efficacy of cavitation jets for heat transfer enhancement was demonstrated. The cavitation jet was formed from a cluster of cavitation bubbles… (more)

Tillery, Steven W.

2005-01-01T23:59:59.000Z

248

Evaluation of Transient Heat Transfer Coefficient Evolution in ...  

Science Conference Proceedings (OSTI)

As known, physical and geometrical aspects play a fundamental role on the heat transfer conditions during the solidification process. This high dependence of ...

249

HEAT TRANSFER IN UNDERGROUND HEATING EXPERIMENTS IN GRANITE, STRIPA, SWEDEN  

E-Print Network (OSTI)

CLOSED-FORM INTEGRAL SOLUTIONS FOR LINEAR HEAT CONDUCTION.For linear heat conduction in a homogeneous, isotropiclaw of similitude for linear heat conduction was utilized to

Chan, T.

2010-01-01T23:59:59.000Z

250

Heat transfer and pressure drop in tape generated swirl flow  

E-Print Network (OSTI)

The heat transfer and pressure drop characteristics of water in tape generated swirl flow were investigated. The test sections were electrically heated small diameter nickel tubes with tight fitting full length Inconel ...

Lopina, Robert F.

1967-01-01T23:59:59.000Z

251

Comparison of heat transfer in solar collectors with heat pipe versus flow through absorbers  

DOE Green Energy (OSTI)

Analysis of heat transfer in solar collectors with heat pipe absorbers is compared to that for collectors with flow through absorbers. Both pumped and thermosiphon systems that produce hot water or other heated fluids are discussed. In these applications the heat pipe absorber suffers a heat transfer penalty compared with the flow through absorber, but in many cases the penalty can be minimized by proper design at the heat pipe condenser and system manifold. When the solar collector is used to drive an absorption chiller, the heat pipe absorber has better heat transfer characteristics than the flow through absorber.

Hull, J.R.

1985-01-01T23:59:59.000Z

252

Heat transfer and condensation of water vapour from humid air in compact heat exchangers.  

E-Print Network (OSTI)

??In this thesis, an experimental and simulation study of heat transfer in water-to-air compact-plate heat exchanger is presented. A compact-plate heat exchanger made of polypropylene,… (more)

Saraireh, Mohammad

2012-01-01T23:59:59.000Z

253

HEAT TRANSFER IN UNDERGROUND HEATING EXPERIMENTS IN GRANITE, STRIPA, SWEDEN  

E-Print Network (OSTI)

law of similitude for linear heat conduction was utilized tothe analogy between heat conduction and fluid flow in por­the effects of heat conduction through the vermiculite heat

Chan, T.

2010-01-01T23:59:59.000Z

254

Heat transfer between stratified immiscible liquid layers driven by gas bubbling across the interface  

SciTech Connect

The modeling of molten core debris in the CORCON and VANESA computer codes as overlying, immiscible liquid layers is discussed as it relates to the transfer of heat and mass between the layers. This initial structure is identified and possible configurations are discussed. The stratified, gas-sparged configuration that is presently employed in CORCON and VANESA is examined and the existing literature for interlayer heat transfer is assessed. An experiment which was designed to measure interlayer heat transfer with gas sparging is described. The results are presented and compared to previously existing models. A dimensionless correlation for stratified, interlayer heat transfer with gas sparging is developed. This relationship is recommended for inclusion in CORCON-MOD2 for heat transfer between stratified, molten liquid layers. 12 refs., 6 figs., 3 tabs.

Greene, G.A.; Irvine, T.F. Jr.

1988-01-01T23:59:59.000Z

255

Heat transfer investigations in a slurry bubble column  

SciTech Connect

Slurry bubble columns, for use in Fisher-Tropsch synthesis, have been investigated. Two bubble columns (0.108 and 0.305 m internal diameter) were set up and experiments were conducted to determine gas holdup and heat transfer coefficients. These columns were equipped with either single heat transfer probes of different diameters, or bundles of five-, seven- or thirty-seven tubes. The experiments were conducted for two- and three-phase systems; employing for gas phase: air and nitrogen, liquid phase: water and Therminol-66, and solid phase: red iron oxide (1.02, 1.70 and 2.38 {mu}m), glass beads (50.0, 90.0, 119.0 and 143.3 {mu}m), silica sand (65 {mu}), and magnetite (28.0, 35.7, 46.0, 58.0, 69.0, 90.5, 115.5, and 137.5 {mu}m). The column temperature was varied between 298--523 K, gas velocity between 0--40 cm/s, and solids concentration between 0--50 weight percent. The holdup and heat transfer data as a function of operating and system parameters were employed to assess the available correlations and semitheoretical models, and to develop new correlations. Information concerning the design and scale-up of larger units is presented. Specific research work that need to be undertaken to understand the phenomena of heat transfer and gas holdup is outlined so that efficient gas conversion and catalyst usage may be accomplished in slurry bubble columns. 130 refs., 177 figs., 54 tabs.

Saxena, S.C.; Rao, N.S.; Vadivel, R.; Shrivastav, S.; Saxena, A.C.; Patel, B.B.; Thimmapuram, P.R.; Kagzi, M.Y.; Khan, I.A.; Verma, A.K.

1991-02-01T23:59:59.000Z

256

Prospects for Money Transfer Models  

E-Print Network (OSTI)

Recently, in order to explore the mechanism behind wealth or income distribution, several models have been proposed by applying principles of statistical mechanics. These models share some characteristics, such as consisting of a group of individual agents, a pile of money and a specific trading rule. Whatever the trading rule is, the most noteworthy fact is that money is always transferred from one agent to another in the transferring process. So we call them money transfer models. Besides explaining income and wealth distributions, money transfer models can also be applied to other disciplines. In this paper we summarize these areas as statistical distribution, economic mobility, transfer rate and money creation. First, money distribution (or income distribution) can be exhibited by recording the money stock (flow). Second, the economic mobility can be shown by tracing the change in wealth or income over time for each agent. Third, the transfer rate of money and its determinants can be analyzed by tracing t...

Wang, Y; Xi, N; Wang, Yougui; Ding, Ning; Xi, Ning

2005-01-01T23:59:59.000Z

257

Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump  

DOE Patents (OSTI)

Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium. A combination of weak and rich liquor working solution is used as the heat transfer medium.

Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

1996-12-03T23:59:59.000Z

258

Gas heat transfer in a heated vertical channel under deteriorated turbulent heat transfer regime  

E-Print Network (OSTI)

Passive cooling via natural circulation of gas after a loss of coolant (LOCA) accident is one of the major goals of the Gas-cooled Fast Reactor (GFR). Due to its high surface heat flux and low coolant velocities under ...

Lee, Jeongik

2007-01-01T23:59:59.000Z

259

Gas Heat Transfer in a Heated Vertical Channel under Deteriorated Turbulent Heat Transfer Regime  

E-Print Network (OSTI)

Passive cooling via natural circulation of gas after a loss of coolant (LOCA) accident is one of the major goals of the Gas-cooled Fast Reactor (GFR). Due to its high surface heat flux and low coolant velocities under ...

Lee, Jeongik

260

Ground-Coupled Heat and Moisture Transfer from Buildings; Part 2: Application (Preprint)  

DOE Green Energy (OSTI)

In this paper the effects of moisture on the heat transfer from two basic types of building foundations, a slab-on-grade and a basement, are examined. A two-dimensional finite element heat and moisture transfer program is used to show the effects of precipitation, soil type, foundation insulation, water table depth, and freezing on the heat transfer from the building foundation. Comparisons are made with a simple heat conduction model to illustrate the dependency of the soil thermal conductivity on moisture content.

Deru, M.P. (National Renewable Energy Laboratory); Kirkpatrick, A.T. (Colorado State University)

2001-02-21T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump  

DOE Patents (OSTI)

Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium.

Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI); Marsala, Joseph (Glen Ellyn, IL)

1994-11-29T23:59:59.000Z

262

Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools  

E-Print Network (OSTI)

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.

Gustavsen, Arild

2009-01-01T23:59:59.000Z

263

Heat and moisture transfer through clothing  

E-Print Network (OSTI)

capacitance of clothing. Heat capacity of the clothing hasSuffix a cl c e m n r s area (m²) specific heat capacity (J/kgK) heat capacity (J/K) clothing surface area factor view

Voelker, Conrad; Hoffmann, Sabine; Kornadt, Oliver; Arens, Edward; Zhang, Hui; Huizenga, Charlie

2009-01-01T23:59:59.000Z

264

Engineering Fundamentals - Heat Transfer & Fluid Flow, Version 6.0  

Science Conference Proceedings (OSTI)

The Heat Transfer and Fluid Flow module covers basic terms and concepts of heat transfer and fluid flow and discusses their applications in nuclear power plants. This course will help new engineers understand how their work might impact and/or be ...

2013-01-17T23:59:59.000Z

265

Enhanced radiative heat transfer between nanostructured gold plates  

E-Print Network (OSTI)

We compute the radiative heat transfer between nanostructured gold plates in the framework of the scattering theory. We predict an enhancement of the heat transfer as we increase the depth of the corrugations while keeping the distance of closest approach fixed. We interpret this effect in terms of the evolution of plasmonic and guided modes as a function of the grating's geometry.

R. Guérout; J. Lussange; F. S. S. Rosa; J. -P. Hugonin; D. A. R. Dalvit; J. -J. Greffet; A. Lambrecht; S. Reynaud

2012-03-07T23:59:59.000Z

266

The heat transfer mechanism in aqueous foam flow in a channel  

Science Conference Proceedings (OSTI)

The Heat transfer mechanism in two-phase aqueous foam flow was investigated for developing energy-efficient heat exchangers. Such heat exchangers can provide low consumption of energy resources due to enhanced heat transfer rates. An enhanced heat transfer ... Keywords: aqueous foam flow, heat exchangers, heat transfer

Irena Gabrielaitien?; Jonas Gylys; Rolandas Jonynas; Tadas Ždankus

2011-12-01T23:59:59.000Z

267

Dual circuit embossed sheet heat transfer panel  

DOE Patents (OSTI)

A heat transfer panel provides redundant cooling for fusion reactors or the like environment requiring low-mass construction. Redundant cooling is provided by two independent cooling circuits, each circuit consisting of a series of channels joined to inlet and outlet headers. The panel comprises a welded joinder of two full-size and two much smaller partial-size sheets. The first full-size sheet is embossed to form first portions of channels for the first and second circuits, as well as a header for the first circuit. The second full-sized sheet is then laid over and welded to the first full-size sheet. The first and second partial-size sheets are then overlaid on separate portions of the second full-sized sheet, and are welded thereto. The first and second partial-sized sheets are embossed to form inlet and outlet headers, which communicate with channels of the second circuit through apertures formed in the second full-sized sheet. 6 figs.

Morgan, G.D.

1984-02-21T23:59:59.000Z

268

Dual circuit embossed sheet heat transfer panel  

DOE Patents (OSTI)

A heat transfer panel provides redundant cooling for fusion reactors or the like environment requiring low-mass construction. Redundant cooling is provided by two independent cooling circuits, each circuit consisting of a series of channels joined to inlet and outlet headers. The panel comprises a welded joinder of two full-size and two much smaller partial-size sheets. The first full-size sheet is embossed to form first portions of channels for the first and second circuits, as well as a header for the first circuit. The second full-sized sheet is then laid over and welded to the first full-size sheet. The first and second partial-size sheets are then overlaid on separate portions of the second full-sized sheet, and are welded thereto. The first and second partial-sized sheets are embossed to form inlet and outlet headers, which communicate with channels of the second circuit through apertures formed in the second full-sized sheet.

Morgan, Grover D. (St. Louis County, MO)

1984-01-01T23:59:59.000Z

269

Heat transfer between elastic solids with randomly rough surfaces  

E-Print Network (OSTI)

We study the heat transfer between elastic solids with randomly rough surfaces. We include both the heat transfer from the area of real contact, and the heat transfer between the surfaces in the noncontact regions. We apply a recently developed contact mechanics theory, which accounts for the hierarchical nature of the contact between solids with roughness on many different length scales. For elastic contact, at the highest (atomic) resolution the area of real contact typically consists of atomic (nanometer) sized regions, and we discuss the implications of this for the heat transfer. For solids with very smooth surfaces, as is typical in many modern engineering applications, the interfacial separation in the non-contact regions will be very small, and for this case we show the importance of the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies.

B. N. J. Persson; B. Lorenz; A. I. Volokitin

2009-08-27T23:59:59.000Z

270

Heat Transfer Fluids for Solar Water Heating Systems | Department...  

NLE Websites -- All DOE Office Websites (Extended Search)

exchanger. | Photo from iStockphoto.com Heat Exchangers for Solar Water Heating Systems Rooftop solar water heaters need regular maintenance to operate at peak efficiency. |...

271

A Modelling of Heat Losses in Aluminium Reduction Cell with ...  

Science Conference Proceedings (OSTI)

Using of anodes with slots chanegd that heat transfer to a great extent.In order to Investigate heat loss dynamics in reduction cells with slot anodes,a modelling ...

272

Some aspects of the computer simulation of conduction heat transfer and phase change processes  

DOE Green Energy (OSTI)

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.

Solomon, A. D.

1982-04-01T23:59:59.000Z

273

Near-field radiative heat transfer for structured surfaces  

E-Print Network (OSTI)

We apply an analytical approach for determining the near-field radiative heat transfer between a metallic nanosphere and a planar semi-infinite medium with some given surface structure. This approach is based on a perturbative expansion, and evaluated to first order in the surface profile. With the help of numerical results obtained for some simple model geometries we discuss typical signatures that should be obtainable with a near-field scanning thermal microscope operated in either constant-height or constant-distance mode.

Svend-Age Biehs; Oliver Huth; Felix Rüting

2011-03-15T23:59:59.000Z

274

Error Analysis of Heat Transfer for Finned-Tube Heat-Exchanger Text-Board  

E-Print Network (OSTI)

In order to reduce the measurement error of heat transfer in water and air side for finned-tube heat-exchanger as little as possible, and design a heat-exchanger test-board measurement system economically, based on the principle of test-board system error analyses and design, the equation of measurement error of heat transfer in air side and water side about orifice meter for the finned-tube heat-exchanger was obtained. This paper studies the major factors that may influence the largest admitted measurement error of measurement instruments for heat transfer in water and air side, and analyzes the degree that water temperature and pressure measurement influence heat transfer in water side, and the degree that wet bulb temperature difference measurement influences heat transfer in air side. Finally, this paper indicates that the key problem of reducing heat transfer in water side is water temperature measurement of the in-out pipe of heat-exchanger, and wet bulb temperature difference is a key to decrease the heat transfer in air side for finned-tube heat-exchanger. This paper gives a theoretical instruction for designing the measurement system of a finned-tube heat-exchanger test-board

Chen, Y.; Zhang, J.

2006-01-01T23:59:59.000Z

275

Enhanced two phase flow in heat transfer systems  

DOE Patents (OSTI)

A family of structures and designs for use in devices such as heat exchangers so as to allow for enhanced performance in heat exchangers smaller and lighter weight than other existing devices. These structures provide flow paths for liquid and vapor and are generally open. In some embodiments of the invention, these structures can also provide secondary heat transfer as well. In an evaporate heat exchanger, the inclusion of these structures and devices enhance the heat transfer coefficient of the evaporation phase change process with comparable or lower pressure drop.

Tegrotenhuis, Ward E; Humble, Paul H; Lavender, Curt A; Caldwell, Dustin D

2013-12-03T23:59:59.000Z

276

Effect of microfouling on heat-transfer efficiency  

DOE Green Energy (OSTI)

Field experiments, performed at Keahole Point, Hawaii and in the Gulf of Mexico, were designed to determine the relationship between decreased heat transfer efficiency and the accumulation of corrosion and/or biofouling films on heat exchanger surfaces. The sample tubes were maintained under conditions simulating those of an Ocean Thermal Energy Conversion (OTEC) system and data from the two sites have been compared. Seawater flowed through 2.54 (internal diameter) metal tubes at approximately 1.8m sec/sup -1/. Four types of tubes were used: 5052 Aluminum (A1), Grade 2 titanium (Ti), 90-10 copper-nickel (Cu-Ni) and Allegheny-Ludlum 6X stainless ssteel (SS). All surfaces were colonized by microorganisms, though colonization of the Cu-Ni surface was initially retarded. Total film weight was greatest for the Al and Cu-Ni surfaces which were characterized by corrosion as well as microbial fouling. The total organic carbon: total nitrogen ratios of the fouling films from Ti, Al, SS and Cu-Ni, 4.2, 4.0, 4.8 and 7.9 respectively, remained constant throughout the experiment. The degradation of heat transfer efficiency due to the formation of fouling layers on Ti and SS is neither linear nor a simple exponential function. A microfouling model is proposed for corrosion-resistant surfaces that is consistent with field observations.

Little, B.; Berger, L.R.

1980-01-01T23:59:59.000Z

277

Cryogenic apparatus for study of near-field heat transfer  

Science Conference Proceedings (OSTI)

For bodies spaced in vacuum at distances shorter than the wavelength of the thermal radiation, radiative heat transfer substantially increases due to the contribution of evanescent electromagnetic waves. Experimental data on heat transfer in near-field regime are scarce. We have designed a cryogenic apparatus for the study of heat transfer over microscopic distances between metallic and non-metallic surfaces. Using a mechanical positioning system, a planeparallel gap between the samples, concentric disks, each 35 mm in diameter, is set and varied from 10{sup 0} to 10{sup 3} {mu}m. The heat transferred from the hot (10 - 100 K) to the cold sample ({approx}5 K) sinks into a liquid helium bath through a thermal resistor, serving as a heat flux meter. Transferred heat power within {approx}2 nW/cm{sup 2} and {approx}30 {mu}W/cm{sup 2} is derived from the temperature drop along the thermal resistor. For tungsten samples, the distance of the near-field effect onset was inversely proportional to temperature and the heat power increase was observed up to three orders of magnitude greater than the power of far-field radiative heat transfer.

Kralik, T.; Hanzelka, P.; Musilova, V.; Srnka, A.; Zobac, M. [Institute of Scientific Instruments of the ASCR, v.v.i., Kralovopolska 147, Brno (Czech Republic)

2011-05-15T23:59:59.000Z

278

Trace formulas for nonequilibrium Casimir interactions, heat radiation, and heat transfer for arbitrary objects  

E-Print Network (OSTI)

We present a detailed derivation of heat radiation, heat transfer, and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal nonequilibrium. The results can be expressed ...

Bimonte, Giuseppe

279

The deterioration in heat transfer to fluids at supercritical pressure and high heat fluxes  

E-Print Network (OSTI)

At slightly supercritical pressure and in the neighborhood of the pseudo-critical temperature (defined as the temperature corresponding to the peak in specific heat at the operating pressure), the heat transfer coefficient ...

Shiralkar, B. S.

1968-01-01T23:59:59.000Z

280

Prospects for Money Transfer Models  

E-Print Network (OSTI)

Summary. Recently, in order to explore the mechanism behind wealth or income distribution, several models have been proposed by applying principles of statistical mechanics. These models share some characteristics, such as consisting of a group of individual agents, a pile of money and a specific trading rule. Whatever the trading rule is, the most noteworthy fact is that money is always transferred from one agent to another in the transferring process. So we call them money transfer models. Besides explaining income and wealth distributions, money transfer models can also be applied to other disciplines. In this paper we summarize these areas as statistical distribution, economic mobility, transfer rate and money creation. First, money distribution (or income distribution) can be exhibited by recording the money stock (flow). Second, the economic mobility can be shown by tracing the change in wealth or income over time for each agent. Third, the transfer rate of money and its determinants can be analyzed by tracing the transferring process of each one unit of money. Finally, money creation process can also be investigated by permitting agents go into debts. Some future extensions to these models are anticipated to be structural improvement and generalized mathematical analysis.

Yougui Wang; Ning Ding; Ning Xi

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Modeling Surface Sensible Heat Flux Using Surface Radiative Temperatures in a Simple Urban Area  

Science Conference Proceedings (OSTI)

Sensible heat fluxes over a light industrial area in Vancouver, British Columbia, Canada, are analyzed from observed tower fluxes and modeled using a bulk heat transfer approach. The bulk transfer models are initialized using remotely sensed ...

J. A. Voogt; C. S. B. Grimmond

2000-10-01T23:59:59.000Z

282

Heat Transfer of a Multiple Helical Coil Heat Exchanger Using a Microencapsulated Phase Change Material Slurry  

E-Print Network (OSTI)

The present study has focused on the use of coil heat exchangers (CHEs) with microencapsulated phase change material (MPCM) slurries to understand if CHEs can yield greater rates of heat transfer. An experimental study was conducted using a counterflow CHE consisting of 3 helical coils. Two separate tests were conducted, one where water was used as heat transfer fluid (HTF) on the coil and shell sides, respectively; while the second one made use of MPCM slurry and water on the coil and shell sides, respectively. The NTU-effectiveness relationship of the CHE when MPCM fluid is used approaches that of a heat exchanger with a heat capacity ratio of zero. The heat transfer results have shown that when using a MPCM slurry, an increase in heat transfer rate can be obtained when compared to heat transfer results obtained using straight heat transfer sections. It has been concluded that the increased specific heat of the slurry as well as the fluid dynamics in helical coil pipes are the main contributors to the increased heat transfer.

Gaskill, Travis

2011-12-01T23:59:59.000Z

283

Measurement of flow field and local heat transfer distribution on a scraped heat exchanger crystalliser surface  

E-Print Network (OSTI)

Measurement of flow field and local heat transfer distribution on a scraped heat exchanger.ravelet@laposte.net Geert-Jan Witkamp G.J.Witkamp@xs4all.nl Abstract In a cylindrical scraped heat exchanger crystallizer exchanger surface has been studied by direct measurements of the heat exchanger surface temperature

Paris-Sud XI, Université de

284

Numerical study of 2D heat transfer in a scraped surface heat exchanger  

E-Print Network (OSTI)

Numerical study of 2D heat transfer in a scraped surface heat exchanger K.-H. Sun a,*, D.L. Pyle heat exchanger with non- Newtonian power law fluids is undertaken. Numerical results are generated of scraped surface heat exchanger design are assessed in the light of the results. Ã? 2003 Elsevier Ltd. All

285

Rheology and Convective Heat Transfer of Colloidal Gas Aphrons in Horizontal Minichannels  

E-Print Network (OSTI)

Single-phase convective heat transfer in microchannels: aand Newell, M. E. , 1967. Heat transfer in fully developed3 /s at 130 W. Water CGA Heat Transfer Coefficient, h (W/m 2

Tseng, H.; Pilon, L.; Warrier, G.

2006-01-01T23:59:59.000Z

286

Heat-transfer dynamics during cryogen spray cooling of substrate at different initial temperatures  

E-Print Network (OSTI)

Aguilar G 2004 Radial heat transfer dynamics during cryogenof droplet dynamics and heat transfer in spray cooling Exp.S0031-9155(04)84030-2 Heat-transfer dynamics during cryogen

Jia, W; Aguilar, G; Wang, G X; Nelson, J S

2004-01-01T23:59:59.000Z

287

HEAT TRANSFER DURING THE SHOCK-INDUCED IGNITION OF AN EXPOLSIVE GAS  

E-Print Network (OSTI)

11 Stagnation Point Heat Transfer Measurements in Air atR.M. , and Kemp, N.H. , Heat Transfer from High TemperatureProceedings of the 1963 Heat Transfer and Fluid Mechanics

Heperkan, H.

2013-01-01T23:59:59.000Z

288

MEASUREMENTS OF HEAT TRANSFER TO HELIUM II AT ATMOSPHERIC PRESSURE IN A CONFINED GEOMETRY  

E-Print Network (OSTI)

M. X. Francois-:- "Heat Transfer Properties in a VerticalK. T - Tb (K) Fig. 4 . Heat transfer at the lambda point.B. The difference in the heat transfer characteristics on

Warren, R.P.

2011-01-01T23:59:59.000Z

289

Experimental study of natural convection heat transfer through an aperture in passive solar heated buildings  

DOE Green Energy (OSTI)

The objective of this study is to obtain correlations between natural convection heat transfer through an aperture and temperature difference between the two rooms. A one-fifth similitude model of a two-room building is used. The model is filled with Freon gas to satisfy similarity of the experiment to full-scale conditions in air. The experimental apparatus and experimental techniques are explained. Experimental results are presented in terms of Grashof, Nusselt, and Prandtl numbers. The effects of the height, the width, and the vertical position of the apertures are investigated, as is the effect of the room volume.

Yamaguchi, Kenjiro

1984-01-01T23:59:59.000Z

290

Khounsary Named Associate Editor of ASME Journal of Heat Transfer  

NLE Websites -- All DOE Office Websites (Extended Search)

New Science with the APS Superconducting Undulator New Science with the APS Superconducting Undulator Young of XSD Named Associate Editor of New Journal "Structural Dynamics" The Daguerreotype and the X-ray: A Deep Look Questions Rise about Seeding For Ocean C02 Sequestration X-ray Method Shows How Frog Embryos Could Help Thwart Disease APS News Archives: 2012 | 2011 | 2010 | 2009 2008 | 2007 | 2006 | 2005 2004 | 2003 | 2002 | 2001 2000 Subscribe to APS News rss feed Khounsary Named Associate Editor of ASME Journal of Heat Transfer October 22, 2013 Bookmark and Share Ali Khounsary Ali Khounsary of the APS Engineering Support Division has been appointed as an Associate Editor of the ASME Journal of Heat Transfer. The Journal of Heat Transfer, in publication since 1879, "disseminates information of permanent interest in the areas of heat and mass transfer.

291

FEHM (Finite Element Heat and Mass Transfer Code)  

NLE Websites -- All DOE Office Websites (Extended Search)

FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. June 29, 2013 software FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. Available for thumbnail of Feynman Center (505) 665-9090 Email FEHM (Finite Element Heat and Mass Transfer Code) FEHM is used to simulate groundwater and contaminant flow and transport in deep and shallow, fractured and un-fractured porous media throughout the US DOE complex. FEHM has proved to be a valuable asset on a variety of

292

Survey and evaluation of techniques to augment convective heat transfer  

E-Print Network (OSTI)

This report presents a survey and evaluation of the numerous techniques which have been shown to augment convective heat transfer. These techniques are: surface promoters, including roughness and treatment; displaced ...

Bergles A. E.

1965-01-01T23:59:59.000Z

293

Wind heat transfer coefficient in solar collectors in outdoor conditions  

Science Conference Proceedings (OSTI)

Knowledge of wind heat transfer coefficient, h{sub w}, is required for estimation of upward losses from the outer surface of flat plate solar collectors/solar cookers. In present study, an attempt has been made to estimate the wind induced convective heat transfer coefficient by employing unglazed test plate (of size about 0.9 m square) in outdoor conditions. Experiments, for measurement of h{sub w}, have been conducted on rooftop of a building in the Institute campus in summer season for 2 years. The estimated wind heat transfer coefficient has been correlated against wind speed by linear regression and power regression. Experimental values of wind heat transfer coefficient estimated in present work have been compared with studies of other researchers after normalizing for plate length. (author)

Kumar, Suresh; Mullick, S.C. [Centre for Energy Studies, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi 110 016 (India)

2010-06-15T23:59:59.000Z

294

Aspects of Heat Transfer During Production of Remelt Ingot Using ...  

Science Conference Proceedings (OSTI)

Sep 1, 2001 ... Aspects of Heat Transfer During Production of Remelt Ingot Using Chain Casters by J.E Grandfield, TT Nguyen, G. Redden and J.A. Taylor ...

295

Design and fabrication of heat transfer surfaces from superplastic material  

Science Conference Proceedings (OSTI)

The production of complex heat transfer surfaces (i.e., those without straight fins) is restricted by available fabrication techniques, materials, geometries, and cost. Based on the superplastic sheet thermoforming process, a new technique for fabricating ...

J. B. Randolph; F. K. King

1972-05-01T23:59:59.000Z

296

Heat transfer during film condensation of a liquid metal vapor  

E-Print Network (OSTI)

The object of this investigation is to resolve the discrepancy between theory and experiment for the case of heat transfer durirnfilm condensation of liquid metal vapors. Experiments by previous investigators have yielded ...

Sukhatme, S. P.

1964-01-01T23:59:59.000Z

297

Investigation of 3-D Heat Transfer Effects in Fenestration Products.  

E-Print Network (OSTI)

??ABSTRACT INVESTIGATION OF 3-D HEAT TRANSFER EFFECTS IN FENESTRATION PRODUCTS SEPTEMBER 2010 SNEH KUMAR B. TECH., INDIAN INSTITUTE OF TECHNOLOGY, CHENNAI INDIA M.S.M.E., UNIVERSITY OF… (more)

Kumar, Sneh

2010-01-01T23:59:59.000Z

298

Molecular Dynamics Simulations of Heat Transfer In Nanoscale Liquid Films  

E-Print Network (OSTI)

Molecular Dynamics (MD) simulations of nano-scale flows typically utilize fixed lattice crystal interactions between the fluid and stationary wall molecules. This approach cannot properly model thermal interactions at the wall-fluid interface. In order to properly simulate the flow and heat transfer in nano-scale channels, an interactive thermal wall model is developed. Using this model, the Fourier’s law of heat conduction is verified in a 3.24 nm height channel, where linear temperature profiles with constant thermal conductivity is obtained. The thermal conductivity is verified using the predictions of Green-Kubo theory. MD simulations at different wall wettability ( ??f /? ) and crystal bonding stiffness values (K) have shown temperature jumps at the liquid/solid interface, corresponding to the well known Kapitza resistance. Using systematic studies, the thermal resistance length at the interface is characterized as a function of the surface wettability, thermal oscillation frequency, wall temperature and thermal gradient. An empirical model for the thermal resistance length, which could be used as the jump-coefficient of a Navier boundary condition, is developed. Temperature distributions in the nano-channels are predicted using analytical solution of the continuum heat conduction equation subjected to the new temperature jump condition, and validated using the MD results. Momentum and heat transfer in shear driven nanochannel flows are also investigated. Work done by the viscous stresses heats the fluid, which is dissipated through the channel walls, maintained at isothermal conditions. Spatial variations in the fluid density, kinematic viscosity, shear- and energy dissipation rates are presented. The energy dissipation rate is almost a constant for ??f /? < 0.6, which results in parabolic temperature profiles in the domain with temperature jumps due to the Kapitza resistance at the liquid/solid interfaces. Using the energy dissipation rates predicted by MD simulations and the continuum energy equation subjected to the temperature jump boundary conditions developed in this study, the analytical solutions are obtained for the temperature profiles, which agree well with the MD results.

Kim, Bo Hung

2009-05-01T23:59:59.000Z

299

Numerical Modeling of Heat Pipe Radiator and Fin Size Optimization for Low and No Gravity Environments.  

E-Print Network (OSTI)

??A heat-pipe radiator element has been designed and modeled to study the efficiency of heat transfer for low and no gravity environments, like in lunar… (more)

Bieger, Virginia Ruth

2013-01-01T23:59:59.000Z

300

On Water Flow in Hot Fractured Rock -- A Sensitivity Study on the Impact of Fracture-Matrix Heat Transfer  

E-Print Network (OSTI)

is related to the heat transfer between the two phasespossibly be affected. Heat transfer from the matrix can beof Fracture-Matrix Heat Transfer Jens T. Birkholzer and

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Thermal single-well injection-withdrawal tracer tests for determining fracture-matrix heat transfer area  

E-Print Network (OSTI)

Testing for Estimating Heat Transfer Area in FracturedFRACTURE-MATRIX HEAT TRANSFER AREA Karsten Pruess andimprove the flow and heat transfer characteristics of the

Pruess, K.

2011-01-01T23:59:59.000Z

302

Two-Dimensional Computational Fluid Dynamics and Conduction Simulations of Heat Transfer in Horizontal Window Frames with Internal Cavities  

E-Print Network (OSTI)

the two-dimensional heat transfer through building products.Gustavsen, A. 2001. Heat transfer in window frames withand CFD Simulations of Heat Transfer in Horizontal Window

Gustavsen, Arlid

2008-01-01T23:59:59.000Z

303

Enhancement of heat transfer for ground source heat pump systems.  

E-Print Network (OSTI)

??Uptake of geothermal heat pump (GSHP) systems has been slow in some parts of the world due to the unpredictable operational performance, large installation space… (more)

Mori, Hiromi

2010-01-01T23:59:59.000Z

304

Advanced turbine cooling, heat transfer, and aerodynamic studies  

DOE Green Energy (OSTI)

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

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

1995-12-31T23:59:59.000Z

305

Handbook of single-phase convective heat transfer  

Science Conference Proceedings (OSTI)

This book presents a comprehensive collection of convective heat transfer basics, methods of calculations, tables, charts and design parameters involving single-phase flows - the most commonly experienced mode in heat transfer problems. Topics covered include natural and forced convection under a wise variety of design conditions, such as ducts, crossflows, turbulent conditions, transitional states, curved and coiled ducts, over rods in metals and through bends, valves and fittings. The book provides sections on radiation interaction and fouling conditions.

Kakac, S.; Shah, R.K.; Aung, W.

1987-01-01T23:59:59.000Z

306

Mpemba effect, Newton cooling law and heat transfer equation  

E-Print Network (OSTI)

In this work we suggest a simple theoretical solution of the Mpemba effect in full agreement with known experimental data. This solution follows simply as an especial approximation (linearization) of the usual heat (transfer) equation, precisely linearization of the second derivation of the space part of the temperature function (as it is well-known Newton cooling law can be considered as the effective approximation of the heat (transfer) equation for constant space part of the temperature function).

Vladan Pankovic; Darko V. Kapor

2010-05-06T23:59:59.000Z

307

Global existence result for phase transformations with heat transfer in shape memory alloys  

E-Print Network (OSTI)

We consider three-dimensional models for rate-independent processes describing materials undergoing phase transformations with heat transfer. The problem is formulated within the framework of generalized standard solids by the coupling of the momentum equilibrium equation and the flow rule with the heat transfer equation. Under appropriate regularity assumptions on the initial data, we prove the existence a global solution for this thermodynamically consistent system, by using a fixed-point argument combined with global energy estimates.

Paoli, Laetitia

2011-01-01T23:59:59.000Z

308

Developing Low-Conductance Window Frames: Capabilities and Limitations of Current Window Heat Transfer Design Tools  

E-Print Network (OSTI)

internal cavities the heat transfer process is more complex,heat transfer in these “insulated” zones could be used in the design process

Gustavsen, Arild

2009-01-01T23:59:59.000Z

309

Boiling heat transfer in a hydrofoil-based micro pin fin heat sink  

E-Print Network (OSTI)

-flow boiling over circular tube bundles has been meticulously studied; collected data and correlations for circular tube bundles. For exam- ple, Jensen and Hsu [81] conducted a parametric study of boiling heat transfer in a horizontal tube bundle and reported an increase in local heat transfer coefficient

Peles, Yoav

310

Research on Convective Heat Transfer and Mass Transfer of the Evaporator in Micro/Mini-Channel  

E-Print Network (OSTI)

With the development of science and technology, various heating and cooling equipment have a development trend of micromation. Micro-fabrication processes make it possible to conduct research on condensation heat transfer in micro-channels. Based on the reviewers on the present household air conditioners, the potential requirements for new heat transfer enhancement used for household air conditioners are discussed. Investigations on condensation and boiling of refrigerants in mini/micro channels have indicated that the evaporator and condenser of air conditioner would be more efficient and more compact by using microchannels, and hence it could improve the coefficient of performance of air conditioners to meet the new energy conversion standards in China. The relationship between condensation heat transfer of refrigerants and surface physical characteristics of the evaporator are pointed out and analyzed in order to achieving the corresponding heat transfer coefficients.

Su, J.; Li, J.

2006-01-01T23:59:59.000Z

311

Pool boiling heat transfer characteristics of nanofluids  

E-Print Network (OSTI)

Nanofluids are engineered colloidal suspensions of nanoparticles in water, and exhibit a very significant enhancement (up to 200%) of the boiling Critical Heat Flux (CHF) at modest nanoparticle concentrations (50.1% by ...

Kim, Sung Joong, Ph. D. Massachusetts Institute of Technology

2007-01-01T23:59:59.000Z

312

Molecular Dynamics Method in Microscale Heat Transfer Shigeo Maruyama  

E-Print Network (OSTI)

1 Molecular Dynamics Method in Microscale Heat Transfer Shigeo Maruyama Department of Mechanical://www.photon.t.u-tokyo.ac.jp/~maruyama/ 1. INTRODUCTION Molecular level understandings are becoming more important and molecular based to take account of nuclei in size of molecular clusters. The effect of the surfactant on the heat and mass

Maruyama, Shigeo

313

Heat Transfer Laboratory of the Savannah River Laboratory  

SciTech Connect

The Heat Transfer Laboratory, recently- constructed adjacent to the main Savannah River Laboratory building, was designed to mock up nuclear heating and cooling of reactor components under a variety- of conditions. Nuclear heating is simulated by electrical resistance heating of test sections with a 3 MW directcurrent power supply. Cooling is provided by water. Three test stations (A, B, and C) are available for testing full-size fuel assemblies, measuring flow instabilities, and for measuring burnout heat fluxes. Safeguards provided in the design of the facility and conservative operating procedures minimize or elimnate potential hazards. (auth)

Knoebel, D.H.; Harris, S.D.

1973-10-01T23:59:59.000Z

314

Handbook of radiative heat transfer in high-temperature gases  

Science Conference Proceedings (OSTI)

This work offers both an original method for calculating optical properties of low-temperature plasma at elevated densities ... and an effective new means for calculating radiative heat transfer in hot gases and plasma with arbitrary temperature and pressure distributions. These methods allow for automatic accounting of all details of the plasma spectrum, including the line structure. This volume contains radiant transfer in problems of heat transfer; integration over frequency; methods of partial characteristics; method of effective populations; calculation of partial characteristics; appendix: tabular data.

Soloukhin, R.I.; Golovnev, I.F.; Zamurayev, V.P.; Katsnelson, S.S.; Kovalskaya, G.A.; Sevastyanenko, V.G.; Soloukhin, R.I.

1987-01-01T23:59:59.000Z

315

Non-equilibrium electromagnetic fluctuations: Heat transfer and interactions  

E-Print Network (OSTI)

The Casimir force between arbitrary objects in equilibrium is related to scattering from individual bodies. We extend this approach to heat transfer and Casimir forces in non-equilibrium cases where each body, and the environment, is at a different temperature. The formalism tracks the radiation from each body and its scatterings by the other objects. We discuss the radiation from a cylinder, emphasizing its polarized nature, and obtain the heat transfer between a sphere and a plate, demonstrating the validity of proximity transfer approximation at close separations and arbitrary temperatures.

Matthias Krüger; Thorsten Emig; Mehran Kardar

2011-02-18T23:59:59.000Z

316

Modulation of near-field heat transfer between two gratings  

E-Print Network (OSTI)

We present a theoretical study of near-field heat transfer between two uniaxial anisotropic planar structures. We investigate how the distance and relative orientation (with respect to their optical axes) between the objects affect the heat flux. In particular, we show that by changing the angle between the optical axes it is possible in certain cases to modulate the net heat flux up to 90% at room temperature, and discuss possible applications of such a strong effect.

Svend-Age Biehs; Felipe S. S. Rosa; Philippe Ben-Abdallah

2011-05-18T23:59:59.000Z

317

Active heat transfer enhancement in integrated fan heat sinks  

E-Print Network (OSTI)

Modern computer processors require significant cooling to achieve their full performance. The "efficiency" of heat sinks is also becoming more important: cooling of electronics consumes 1% of worldwide electricity use by ...

Staats, Wayne Lawrence

2012-01-01T23:59:59.000Z

318

Modeling of pulsating heat pipes.  

SciTech Connect

This report summarizes the results of a computer model that describes the behavior of pulsating heat pipes (PHP). The purpose of the project was to develop a highly efficient (as compared to the heat transfer capability of solid copper) thermal groundplane (TGP) using silicon carbide (SiC) as the substrate material and water as the working fluid. The objective of this project is to develop a multi-physics model for this complex phenomenon to assist with an understanding of how PHPs operate and to be able to understand how various parameters (geometry, fill ratio, materials, working fluid, etc.) affect its performance. The physical processes describing a PHP are highly coupled. Understanding its operation is further complicated by the non-equilibrium nature of the interplay between evaporation/condensation, bubble growth and collapse or coalescence, and the coupled response of the multiphase fluid dynamics among the different channels. A comprehensive theory of operation and design tools for PHPs is still an unrealized task. In the following we first analyze, in some detail, a simple model that has been proposed to describe PHP behavior. Although it includes fundamental features of a PHP, it also makes some assumptions to keep the model tractable. In an effort to improve on current modeling practice, we constructed a model for a PHP using some unique features available in FLOW-3D, version 9.2-3 (Flow Science, 2007). We believe that this flow modeling software retains more of the salient features of a PHP and thus, provides a closer representation of its behavior.

Givler, Richard C.; Martinez, Mario J.

2009-08-01T23:59:59.000Z

319

Radiant heat transfer from storage casks to the environment  

SciTech Connect

A spent fuel storage cask must efficiently transfer the heat released by the fuel assemblies through the cask walls to the environment. This heat must be transferred through passive means, limiting the energy transfer mechanisms from the cask to natural convection and radiation heat transfer.. Natural convection is essentially independent of the characteristics of the array of casks, provided there is space between casks to permit a convection loop. Radiation heat transfer, however, depends on the geometric arrangement of the array of casks because the peripheral casks will shadow the interior casks and restrict radiant heat transfer from all casks to the environment. The shadowing of one cask by its neighbors is determined by a view factor that represents the fraction of radiant energy that leaves the surface of a cask and reaches the environment. This paper addresses the evaluation of the view factor between a centrally located spent fuel storage cask and the environment. By combining analytic expressions for the view factor of (1) infinitely long cylinders and (2) finite cylinders with a length-to-diameter ratio of 2 to represent spent fuel storage casks, the view factor can be evaluated for any practical array of spent fuel storage casks.

Carlson, R W; Hovingh, J; Thomas, G R

1999-05-10T23:59:59.000Z

320

Design and operation of solar thermal heat transfer systems  

Science Conference Proceedings (OSTI)

The importance of heat transfer systems in the collection and use of solar energy is discussed. The success or failure of many solar energy systems has been determined by the design of the heat transfer system. This report includes a short summary of some of the DOE sponsored solar industrial process heat sites. From the design, construction, and operation of these systems many lessons were learned which will be important to designers and potential users of solar thermal systems. Also included is a discussion of solar collector foundation over-design that has increased the collector system costs.

Rush, E.E.

1985-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Heat Transfer Enhancement in Separated and Vortex Flows  

SciTech Connect

This document summarizes the research performance done at the Heat Transfer Laboratory of the University of Minnesota on heat transfer and energy separation in separated and vortex flow supported by DOE in the period September 1, 1998--August 31, 2003. Unsteady and complicated flow structures in separated or vortex flows are the main reason for a poor understanding of heat transfer under such conditions. The research from the University of Minnesota focused on the following important aspects of understanding such flows: (1) Heat/mass transfer from a circular cylinder; (2) study of energy separation and heat transfer in free jet flows and shear layers; and (3) study of energy separation on the surface and in the wake of a cylinder in crossflow. The current study used three different experimental setups to accomplish these goals. A wind tunnel and a liquid tunnel using water and mixtures of ethylene glycol and water, is used for the study of prandtl number effect with uniform heat flux from the circular cylinder. A high velocity air jet is used to study energy separation in free jets. A high speed wind tunnel, same as used for the first part, is utilized for energy separation effects on the surface and in the wake of the circular cylinder. The final outcome of this study is a substantial advancement in this research area.

Richard J. Goldstein

2004-05-27T23:59:59.000Z

322

Multidimensional numerical modeling of heat exchangers. [LMFBR  

SciTech Connect

A comprehensive, multidimensional, thermal-hydraulic model is developed for the analysis of shell-and-tube heat exchangers for liquid-metal services. For the shellside fluid, the conservation equations of mass, momentum, and energy for continuum fluids are modified using the concept of porosity, surface permeability and distributed resistance to account for the blockage effects due to the presence of heat-transfer tubes, flow baffles/shrouds, the support plates, etc. On the tubeside, the heat-transfer tubes are connected in parallel between the inlet and outlet plenums, and tubeside flow distribution is calculated based on the plenum-to-plenum pressure difference being equal for all tubes. It is assumed that the fluid remains single-phase on the shell side and may undergo phase-change on the tube side, thereby simulating the conditions of Liquid Metal Fast Breeder Reactor (LMFBR) intermediate heat exchangers (IHX) and steam generators (SG).

Sha, W.T.; Yang, C.I.; Kao, T.T.; Cho, S.M.

1982-01-01T23:59:59.000Z

323

TRANSIENT HEAT TRANSFER IN REACTOR COOLANT CHANNELS  

SciTech Connect

An analysis is presented of the transient behavior of a generalized cooiant channel neglecting temperature dependent reactivity changes. The analysis is applicable to forced convection cooling of heterogeneous reactor fuel elements or electrically heated simulation thereof. Derivations are given for cases of variation of coolant inlet temperature and of heat generation. An approximation is also developed applicable to thin fuel elements. From this, solutions are obtained for cases-of impulsive, step, linear, and step-exponential variations of inlet temperature, and, of impulsive and uniform variations of heat generation. The solutions presented will be of use during preliminary stages of design of new heterogeneous reactor concepts (when the use of computing machines may not be warranted), and, in the design and interpretation of transient experiments simulating reactor fuel channels. (auth)

Stein, R.P.

1957-10-31T23:59:59.000Z

324

A parameterized model of heat storage by lake sediments  

Science Conference Proceedings (OSTI)

A model of seasonal heat storage by lake sediments is proposed oriented at applications in climate modeling and at lake parameterization in numerical weather prediction. The computational efficiency is achieved by reformulating of the heat transfer problem ... Keywords: Bulk model, Climate modeling, Lake temperature, Sediment processes, Temperature wave, Water-sediment exchange

Sergey Golosov; Georgiy Kirillin

2010-06-01T23:59:59.000Z

325

Experimental study on condensation heat transfer of steam on vertical titanium plates with different surface energies  

Science Conference Proceedings (OSTI)

Visual experiments were employed to investigate heat transfer characteristics of steam on vertical titanium plates with/without surface modifications for different surface energies. Stable dropwise condensation and filmwise condensation were achieved on two surface modification titanium plates, respectively. Dropwise and rivulet filmwise co-existing condensation form of steam was observed on unmodified titanium surfaces. With increase in the surface subcooling, the ratio of area ({eta}) covered by drops decreased and departure diameter of droplets increased, resulting in a decrease in condensation heat transfer coefficient. Condensation heat transfer coefficient decreased sharply with the values of {eta} decreasing when the fraction of the surface area covered by drops was greater than that covered by rivulets. Otherwise, the value of {eta} had little effect on the heat transfer performance. Based on the experimental phenomena observed, the heat flux through the surface was proposed to express as the sum of the heat flux through the dropwise region and rivulet filmwise region. The heat flux through the whole surface was the weighted mean value of the two regions mentioned above. The model presented explains the gradual change of heat transfer coefficient for transition condensation with the ratio of area covered by drops. The simulation results agreed well with the present experimental data when the subcooling temperature is lower than 10 C. (author)

Baojin, Qi; Li, Zhang; Hong, Xu; Yan, Sun [State-Key Laboratory of Chemical Engineering, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237 (China)

2011-01-15T23:59:59.000Z

326

Heat Transfer in Superfluids: Effect of Gravity  

E-Print Network (OSTI)

We discuss the influence of an external field on energy transport in superfluid. He-II is not isothermal in presence of Earth gravity; instead, it supports finite temperature gradient given by a Fourier-like equation. We calculate asymptotic behavior of the effective heat resistance in the vicinity of the $\\lambda$-transition.

L. A. Melnikovsky

2004-05-19T23:59:59.000Z

327

A transient heat and mass transfer model of residential attics used to simulate radiant barrier retrofits. Part 2: Validation and simulations  

Science Conference Proceedings (OSTI)

A computer program was developed and used to implement the model described on Part 1 of this paper. The program used an iterative process to predict temperatures and heat fluxes using linear algebra principles. The results from the program were compared to experimental data collected during a three-year period. The model simulated different conditions such as variations in attic ventilation, variations in attic ceiling insulation, and different radiant barrier orientations for summer and winter seasons. It was observed that the model predicted with an error of less than 10% for most cases. This paper presents model results for nonradiant barrier cases as well as cases for radiant barriers installed horizontally on top of the attic floor (HRB) and for radiant barriers stapled to the attic rafters (TRB). Savings produced by radiant barriers and sensitivity analyses are also presented. The model results supported the experimental trend that emissivity was the single most significant parameter that affected the performance of radiant barriers.

Medina, M.A. [Texas A and M Univ., Kingsville, TX (United States). Dept. of Mechanical and Industrial Engineering

1998-02-01T23:59:59.000Z

328

Spray cooling heat-transfer with subcooled trichlorotrifluoroethane (Freon-113) for vertical constant heat flux surfaces  

SciTech Connect

Experiments were done using subcooled Freon-113 sprayed vertically downward. Local and average heat transfers were investigated fro Freon-113 sprays with 40 C subcooling, droplet sizes 200-1250{mu}m, and droplet breakup velocities 5-29 m/s. Full-cone type nozzles were used to generate the spray. Test assemblies consisted of 1 to 6 7.62 cm vertical constant heat flux surfaces parallel with each other and aligned horizontally. Distance between heated surfaces was varied from 6.35 to 76.2 mm. Steady state heat fluxes as high as 13 W/cm{sup 2} were achieved. Dependence on the surface distance from axial centerline of the spray was found. For surfaces sufficiently removed from centerline, local and average heat transfers were identical and correlated by a power relation of the form seen for normal-impact sprays which involves the Weber number, a nondimensionalized temperature difference, and a mass flux parameter. For surfaces closer to centerline, the local heat transfer depended on vertical location on the surface while the average heat transfer was described by a semi-log correlation involving the same parameters. The heat transfer was independent of the distance (gap) between the heated surfaces for the gaps investigated.

Kendall, C.M. [Lawrence Livermore National Lab., CA (United States); Holman, J.P. [Southern Methodist Univ., Dallas, TX (United States). Dept. of Mechanical Engineering

1996-06-06T23:59:59.000Z

329

Preliminary Heat Transfer Studies for the Double Shell Tanks (DST) Transfer Piping  

SciTech Connect

Heat transfer studies were made to determine the thermal characteristics of double-shell tank transfer piping under both transient and steady-state conditions. A number of design and operation options were evaluated for this piping system which is in its early design phase.

HECHT, S.L.

2000-02-15T23:59:59.000Z

330

Dispersed-Flow Film Boiling Heat Transfer Data near Spacer Grids in a Rod Bundle  

Science Conference Proceedings (OSTI)

Technical Paper / Radiation Effects and Their Relationship to Geological Repository / Heat Transfer and Fluid Flow

Graydon L. Yoder; Jr.; David G. Morris; Charles B. Mullins; Larry J. Ott

331

Convective heat transfer inside passive solar buildings  

DOE Green Energy (OSTI)

Natural convection between spaces in a building can play a major role in energy transfer. Two situations are investigated: convection through a single doorway into a remote room, and a convective loop in a two-story house with a south sunspace where a north stairway serves as the return path. A doorway-sizing equation is given for the single-door case. Detailed data are given from the monitoring of airflow in one two-story house and summary data are given for five others. Observations on the nature of the airflow and design guidelines are presented.

Jones, R.W.; Balcomb, J.D.; Yamaguchi, K.

1983-01-01T23:59:59.000Z

332

Generator-absorber-heat exchange heat transfer apparatus and method and use thereof in a heat pump  

DOE Patents (OSTI)

Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use, as the heat transfer medium, the working fluid of the absorption system taken from the generator at a location where the working fluid has a rich liquor concentration.

Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

1998-07-21T23:59:59.000Z

333

Heat Transfer and Alternative Energy Systems Group  

Science Conference Proceedings (OSTI)

... and validates computer models used to predict the energy performance of photovoltaics and other alternative energy production systems in ...

2011-10-31T23:59:59.000Z

334

Development of a carburizing and quenching simulation tool: Determination of heat transfer boundary conditions in salt  

Science Conference Proceedings (OSTI)

In the numerical simulation of the quenching of steel parts, it is desirable to limit the thermal problem to one of conduction in the solid part, with Newtonian cooling on the surface. This avoids the solution of highly transient, non-Boussinesq conjugate heat transfer problems which often involve mixed convection. Of course, the heat transfer coefficient h{sub 1} is in general a function of local surface temperature, and may depend strongly on the part geometry and other parameters. In order to obtain appropriate heat transfer coefficients for quenching thick rings in salt, we solve the conjugate heat transfer problem for representative geometries and determine the heat transfer coefficient from the calculated heat flux at the solid-fluid interface. This is done in a two-stage approach. First, we examine fully coupled solutions obtained from first principles without adjustable empirical parameters using an adaptive finite difference code applicable to simple shapes. The purpose of this part of the procedure is to gain insight into the physics of immersion, free convection and forced convection and to determine the most appropriate forms of the physical properties in the salt. Validation for simple shapes is accomplished by comparison with experimental data reported in the literature. Second, empirical modifications to physical properties and simplified governing equations are used to account for conduction-dominated heat transfer on initial contact and subsequent forced convection during immersion, based on results of the first calculations, so that a commercial finite-volume CFD code can be used to model complex shapes and flow in a quench tank. These results are compared with experimental data for thick rings quenched in salt, and used to calculate surface heat transfer coefficients as functions of temperature and location from the resulting heat flux at the part surface.

Shick, D. [Torrington Co., CT (United States); Walton, H. [Torrington Co., Rutherfordton, NC (United States); Chenoweth, D.R. [Sandia National Lab., Livermore, CA (United States)] [and others

1996-10-01T23:59:59.000Z

335

Heat Transfer in Projecting and Sloped Fenestration Products  

NLE Websites -- All DOE Office Websites (Extended Search)

Heat Transfer in Projecting and Sloped Fenestration Products Heat Transfer in Projecting and Sloped Fenestration Products Speaker(s): Dragan Charlie Curcija Date: May 26, 2010 - 12:00pm Location: 90-3122 The heat transfer performance of fenestration products is routinely determined using computer simulations combined with physical testing. Initial efforts to develop simulation and test procedures for the fenestration products in the 1980's focused on simple planar windows since they are the dominant share of the market. However, once these procedures were developed (with resulting ISO standards and national rating and labeling requirements), manufacturers of more physically complex fenestration products (skylights, green house windows, tubular skylights) demanded procedures for simulating and testing their products. Dr Curcija

336

Analytical and numerical solution of one- and two-dimensional steady heat transfer in a coldplate  

SciTech Connect

We develop analytical models for steady-state, one- and two-dimensional heat transfer in a single-material, flat-plate coldplate. Discrete heat sources are mounted on one side of the plate and heat transfer to a flowing fluid occurs on the other. The models are validated numerically using finite differences. We propose a simple procedure for estimating maximum coldplate temperature at the location of each heat source which includes thermal interaction among the sources. Results from one model are compared with data obtained for a composite coldplate operated in the laboratory. We demonstrate the utility of the models as diagnostic tools to be used for predicting the existence and extent of void volumes and delaminations in the composite material that can occur with coldplates of this type. Based on our findings, recommendations for effective coldplate design are given.

Jones, G.F.; Bennett, G.A.; Bultman, D.H.

1987-01-01T23:59:59.000Z

337

Exploring the Limits of Boiling and Evaporative Heat Transfer Using Micro/Nano Structures  

E-Print Network (OSTI)

Heat Transfer Using Micro/Nano Structures by Ming-Chang Lu AHeat Transfer Using Micro/Nano Structures Copyright 2010 byHeat Transfer Using Micro/Nano Structures by Ming-Chang Lu

Lu, Ming-Chang

2010-01-01T23:59:59.000Z

338

Heat transfer characteristics of a three-phase volume boiling direct contact heat exchanger  

DOE Green Energy (OSTI)

The advantages of direct contact heat transfer over heat transfer utilizing conventional metallic heat exchangers are listed. The performance characteristics of a three-phase direct contact heat exchanger in near counterflow operation were evaluated using water as the continuous phase fluid and refrigerant 113 as the dispersed phase fluid. Conclusions are drawn from the results having to do with refrigerant injection technique, vessel operating height, mass flow rate of refrigerant, water inlet temperature, operation at pinch point temperature differences below 13 to 20/sup 0/C, and operation with a dispersed phase fluid less dense than water. (MHR)

Blair, C.K.; Boehm, R.F.; Jacobs, H.R.

1976-03-01T23:59:59.000Z

339

AN EXPERIMENTAL INVESTIGATION ON HEAT TRANSFER CHARACTERISTICS OF AIR AND CO2 IN MICROTUBES  

E-Print Network (OSTI)

by a cooling capacity, which is delivered in those rooms by heat exchangers where a heat transfer fluid - 2 and Fluid Science, 1-3:17. Mortada S., 2010. "Heat transfer performance of a mini-channel evaporator are mini-channel heat exchangers (MCHE) combining high heat transfer coefficients and low refrigerant

Kandlikar, Satish

340

Low heat transfer, high strength window materials  

DOE Patents (OSTI)

A multi-pane window with improved insulating qualities; comprising a plurality of transparent or translucent panes held in an essentially parallel, spaced-apart relationship by a frame. Between at least one pair of panes is a convection defeating means comprising an array of parallel slats or cells so designed as to prevent convection currents from developing in the space between the two panes. The convection defeating structures may have reflective surfaces so as to improve the collection and transmittance of the incident radiant energy. These same means may be used to control (increase or decrease) the transmittance of solar energy as well as to decouple the radiative transfer between the interior surfaces of the transparent panes.

Berlad, Abraham L. (Stony Brook, NY); Salzano, Francis J. (Patchogue, NY); Batey, John E. (Stony Brook, NY)

1978-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Heat transfer education : Keeping it relevant and vibrant.  

SciTech Connect

The motivation for a fresh look at heat transfer education, both in content and in methodology, is generated by a number of trends in engineering practice. These include the increasing demand for engineers with interdisciplinary skills, rapid integration of technology, emergence of computerized and interactive problem-solving tools, shortening time of concept-to-market, availability of new technologies, and an increasing number of new or redesigned products and processes in which heat transfer plays a part. Examination of heat transfer education in this context can be aided by considering the changes, both qualitatively and quantitatively, in the student, educator, and researcher populations, employment opportunities, in the needs of corporations, government, industry, and universities, and in the relevant technical problems and issues of the day. Such an overview provides the necessary background for charting a response to the difficult question of how to maintain excellence and continuity in heat transfer education in the face of rapid, widespread, and complex changes. The present paper addresses how to make heat transfer education more relevant and stimulating. This paper represents a written summary of a 1996 panel discussion at the 1996 International Mechanical Engineering Conference and Exhibition (IMECE) of the American Society of Mechanical Engineers (ASME) in Atlanta, Georgia, on ''Heat Transfer Education: Keeping it Relevant and Vibrant,'' with significant expansion and amplification by the authors and the panelists in the 1997-98 period. The consensus of the participants is that the steps necessary to ensure the desired outcome in heat transfer education should include: (1) a better understanding of the interaction between the student, course content, and market needs; (2) an appreciation of the need in multidisciplinary industrial environments for engineers trained with a broad background: (3) a revision of the introductory heat transfer course to incorporate illustrative and insightful industrial examples and case studies reducible to order-of-magnitude analyses; (4) a reinforcement of real-world problem-solving abilities in students by introducing them to examples that emphasize multidisciplinary issues in modern thermal management problems and finally (5) industrial collaboration that would provide the educator with meaningful thermal management case studies (and possible funding), the student with an appreciation of industrial practices, and the industrial sponsor with access to academia for assistance in problem solving. Also suggested is an effective regular review program to provide assessment, feedback, and suggestions for quality control to interested institutions on their teaching methodology and materials.

Khounsary, A. M.

1998-08-14T23:59:59.000Z

342

Enhancement and suppression of heat transfer by MHD turbulence  

E-Print Network (OSTI)

We study of the effect of turbulence on heat transfer within magnetized plasmas for energy injection velocities both larger and smaller that the Alfven speed. We find that in the latter regime the heat transfer is partially suppressed, while in the former regime the effects of turbulence depend on the intensity of driving. In fact, the scale l at which the turbulent velocity is equal the Alfven velocity is a new important parameter. When the electron mean free path is larger than l, the stronger the the turbulence, the lower thermal conductivity by electrons is. The turbulent motions, however, induces their own advective heat transport, which, for the parameters of intracluster medium (ICM) provides effective heat diffusivity that exceeds the classical Spitzer value.

A. Lazarian

2006-08-02T23:59:59.000Z

343

Determination of Heat-Transfer Coefficients  

Science Conference Proceedings (OSTI)

..., ASM International, 2009, p 106â??126ASM Handbook, Vol 22A, Fundamentals of Modeling for Metals ProcessingD. S. MacKenzie and A. L. Banka,

344

Enhanced boiling heat transfer in horizontal test bundles  

Science Conference Proceedings (OSTI)

Two-phase flow boiling from bundles of horizontal tubes with smooth and enhanced surfaces has been investigated. Experiments were conducted in pure refrigerant R-113, pure R-11, and mixtures of R-11 and R-113 of approximately 25, 50, and 75% of R-113 by mass. Tests were conducted in two staggered tube bundles consisting of fifteen rows and five columns laid out in equilateral triangular arrays with pitch-to-diameter ratios of 1.17 and 1.5. The enhanced surfaces tested included a knurled surface (Wolverine`s Turbo-B) and a porous surface (Linde`s High Flux). Pool boiling tests were conducted for each surface so that reference values of the heat transfer coefficient could be obtained. Boiling heat transfer experiments in the tube bundles were conducted at pressures of 2 and 6 bar, heat flux values from 5 to 80 kW/m{sup 2}s, and qualities from 0% to 80%, Values of the heat transfer coefficients for the enhanced surfaces were significantly larger than for the smooth tubes and were comparable to the values obtained in pool boiling. It was found that the performance of the enhanced tubes could be predicted using the pool boiling results. The degradation in the smooth tube heat transfer coefficients obtained in fluid mixtures was found to depend on the difference between the molar concentration in the liquid and vapor.

Trewin, R.R.; Jensen, M.K.; Bergles, A.E.

1994-08-01T23:59:59.000Z

345

Combined heat and mass transfer device for improving separation process  

DOE Patents (OSTI)

A two-phase small channel heat exchange matrix simultaneously provides for heat transfer and mass transfer between the liquid and vapor phases of a multi-component mixture at a single, predetermined location within a separation column, significantly improving the thermodynamic efficiency of the separation process. The small channel heat exchange matrix is composed of a series of channels having a hydraulic diameter no greater than 5.0 millimeters for conducting a two-phase coolant. In operation, the matrix provides the liquid-vapor contacting surfaces within the separation column, such that heat and mass are transferred simultaneously between the liquid and vapor phases. The two-phase coolant allows for a uniform heat transfer coefficient to be maintained along the length of the channels and across the surface of the matrix. Preferably, a perforated, concave sheet connects each channel to an adjacent channel to facilitate the flow of the liquid and vapor phases within the column and to increase the liquid-vapor contacting surface area.

Tran, Thanh Nhon (Flossmoor, IL)

1999-01-01T23:59:59.000Z

346

Combined heat and mass transfer device for improving separation process  

DOE Patents (OSTI)

A two-phase small channel heat exchange matrix simultaneously provides for heat transfer and mass transfer between the liquid and vapor phases of a multi-component mixture at a single, predetermined location within a separation column, significantly improving the thermodynamic efficiency of the separation process. The small channel heat exchange matrix is composed of a series of channels having a hydraulic diameter no greater than 5.0 millimeters for conducting a two-phase coolant. In operation, the matrix provides the liquid-vapor contacting surfaces within the separation column, such that heat and mass are transferred simultaneously between the liquid and vapor phases. The two-phase coolant allows for a uniform heat transfer coefficient to be maintained along the length of the channels and across the surface of the matrix. Preferably, a perforated, concave sheet connects each channel to an adjacent channel to facilitate the flow of the liquid and vapor phases within the column and to increase the liquid-vapor contacting surface area. 12 figs.

Tran, T.N.

1999-08-24T23:59:59.000Z

347

Investigation of methods to transfer heat from solar liquid-heating collectors to heat storage tanks. Final report  

DOE Green Energy (OSTI)

A study was made of the methods available to transfer heat from the collector to the water storage tank in water heating systems. In counterflow heat exchangers used in double loop water heating systems, it was found to be more important to use a high water flowrate than a high heat transfer fluid flowrate. It was earlier thought to be best to have matched WC/sub p/ (mass flowrate-specific heat) products in the loops. It was shown in this study that the water WC/sub p/ product should be about twice as large as that of the heat transfer fluid. It was found that neither the heat exchanger type nor the size was very critical, so that very simple criteria were adequate in determining optimum heat exchanger size. It was found that there is a definite system size below which one should use a traced tank or a coil in a tank. Equations and optimization criteria were developed for traced tanks or tanks with coils. At present, there is no quantitative understanding of liquid to liquid (direct contact) heat exchangers, though they are clearly quite effective. Draindown systems are discussed, and several appendices are included on heat transfer and other characteristics of fluid and of equipment.

Horel, J. D.; de Winter, F.

1978-04-20T23:59:59.000Z

348

Enhanced heat transfer with metal wool filled tubes  

SciTech Connect

The Advanced Photon Source (APS) to be constructed at Argonne National Laboratory (ANL) utilizes magnetic devices which generate x-ray beams with very intense heat flux levels. The flux levels encountered can be one or two orders of magnitude higher than those commonly found in nuclear reactors or fusion devices. The beam line elements and optics on such beams pose significant challenge to the researchers and designers to keep them cooled at acceptable levels of surface temperature and/or temperature gradients. Therefore, methods and techniques achieving heat removal enhancement are constantly sought. One such technique suggested and considered is the use of conductive metal wool filled tubes where the filter is brazed to the tube walls. A comparative investigation of the conventionally achievable heat transfer coefficient h'' with water and the wall conductance of a heavy wall copper tube reveals that major resistance is on the coolant side. Therefore, there exists a significant opportunity to improve heat transfer in the tubes by enhancement of the coolant side. To this end a variety of copper wool filled tubes as well as a commercially available enhanced copper tube were subjected to laboratory tests with water and conventional heating to assess the resulting heat transfer improvement. Design improvements using enhanced cooling are discussed in terms of structural weight, controls, grazing angles, the operational reliability. 9 refs., 11 figs., 5 tabs.

Kuzay, T.M.; Collins, J.T.; Khounsary, A.M. (Argonne National Lab., IL (USA)); Morales, G. (Argonne National Lab., IL (USA) Texas Univ., El Paso, TX (USA))

1990-08-01T23:59:59.000Z

349

Investigation of Heat Transfer Conditions in a Reverberatory Melting ...  

Science Conference Proceedings (OSTI)

The model comprises different physical phenomenon as gas f low, chemical reactions, i.e. combustion, conduction, radiation and latent heat release in the metal.

350

Trace formulae for non-equilibrium Casimir interactions, heat radiation and heat transfer for arbitrary objects  

E-Print Network (OSTI)

We present a detailed derivation of heat radiation, heat transfer and (Casimir) interactions for N arbitrary objects in the framework of fluctuational electrodynamics in thermal non-equilibrium. The results can be expressed as basis-independent trace formulae in terms of the scattering operators of the individual objects. We prove that heat radiation of a single object is positive, and that heat transfer (for two arbitrary passive objects) is from the hotter to a colder body. The heat transferred is also symmetric, exactly reversed if the two temperatures are exchanged. Introducing partial wave-expansions, we transform the results for radiation, transfer and forces into traces of matrices that can be evaluated in any basis, analogous to the equilibrium Casimir force. The method is illustrated by (re)deriving the heat radiation of a plate, a sphere and a cylinder. We analyze the radiation of a sphere for different materials, emphasizing that a simplification often employed for metallic nano-spheres is typically invalid. We derive asymptotic formulae for heat transfer and non-equilibrium interactions for the cases of a sphere in front a plate and for two spheres, extending previous results. As an example, we show that a hot nano-sphere can levitate above a plate with the repulsive non-equilibrium force overcoming gravity -- an effect that is not due to radiation pressure.

Matthias Krüger; Giuseppe Bimonte; Thorsten Emig; Mehran Kardar

2012-07-02T23:59:59.000Z

351

Enhanced heat transfer surface for cast-in-bump-covered cooling surfaces and methods of enhancing heat transfer  

DOE Patents (OSTI)

An annular turbine shroud separates a hot gas path from a cooling plenum containing a cooling medium. Bumps are cast in the surface on the cooling side of the shroud. A surface coating overlies the cooling side surface of the shroud, including the bumps, and contains cooling enhancement material. The surface area ratio of the cooling side of the shroud with the bumps and coating is in excess of a surface area ratio of the cooling side surface with bumps without the coating to afford increased heat transfer across the element relative to the heat transfer across the element without the coating.

Chiu, Rong-Shi Paul (Glenmont, NY); Hasz, Wayne Charles (Pownal, VT); Johnson, Robert Alan (Simpsonville, SC); Lee, Ching-Pang (Cincinnati, OH); Abuaf, Nesim (Lincoln City, OR)

2002-01-01T23:59:59.000Z

352

Method of measuring heat influx of a cryogenic transfer system  

DOE Patents (OSTI)

A method is provided for measuring the heat influx of a cryogenic transfer system. A gaseous phase of the cryogen used during normal operation of the system is passed through the system. The gaseous cryogen at the inlet to the system is tempered to duplicate the normal operating temperature of the system inlet. The temperature and mass flow rate of the gaseous cryogen is measured at the outlet of the system, and the heat capacity of the cryogen is determined. The heat influx of the system is then determined from known thermodynamic relationships.

Niemann, Ralph C. (Downers Grove, IL); Zelipsky, Steven A. (Tinley Park, IL); Rezmer, Ronald R. (Lisle, IL); Smelser, Peter (Bruner, MO)

1981-01-01T23:59:59.000Z

353

Heat transfer to water from a vertical tube bundle under natural-circulation conditions. [PWR; BWR  

SciTech Connect

The natural circulation heat transfer data for longitudinal flow of water outside a vertical rod bundle are needed for developing correlations which can be used in best estimate computer codes to model thermal-hydraulic behavior of nuclear reactor cores under accident or shutdown conditions. The heat transfer coefficient between the fuel rod surface and the coolant is the key parameter required to predict the fuel temperature. Because of the absence of the required heat transfer coefficient data base under natural circulation conditions, experiments have been performed in a natural circulation loop. A seven-tube bundle having a pitch-to-diameter ratio of 1.25 was used as a test heat exchanger. A circulating flow was established in the loop, because of buoyancy differences between its two vertical legs. Steady-state and transient heat transfer measurements have been made over as wide a range of thermal conditions as possible with the system. Steady state heat transfer data were correlated in terms of relevant dimensionless parameters. Empirical correlations for the average Nusselt number, in terms of Reynolds number, Rayleigh number and the ratio of Grashof to Reynolds number are given.

Gruszczynski, M.J.; Viskanta, R.

1983-01-01T23:59:59.000Z

354

Investigation of Enhanced Heat Transfer Coefficient with an Electrostatic Grid  

Science Conference Proceedings (OSTI)

Some major contributors to efficiency loss in a fossil or nuclear plant are associated with nucleation of moisture from superheated steam, formation and release of liquid films on turbine surfaces, and the flow and condensation of moist steam into the turbine exhaust and condenser. This report investigates the possible effect of an electrostatic charge on these processes and therefore on heat transfer.

2004-09-15T23:59:59.000Z

355

A mesoscopic description of radiative heat transfer at the nanoscale  

E-Print Network (OSTI)

We present a formulation of the nanoscale radiative heat transfer (RHT) using concepts of mesoscopic physics. We introduce the analog of the Sharvin conductance using the quantum of thermal conductance. The formalism provides a convenient framework to analyse the physics of RHT at the nanoscale. Finally, we propose a RHT experiment in the regime of quantized conductance.

Svend-Age Biehs; Emmanuel Rousseau; Jean-Jacques Greffet

2011-03-11T23:59:59.000Z

356

Heat transfer in inertial confinement fusion reactor systems  

SciTech Connect

The short time and deposition distance for the energy from inertial fusion products results in local peak power densities on the order of 10/sup 18/ watts/m/sup 3/. This paper presents an overview of the various inertial fusion reactor designs which attempt to reduce these peak power intensities and describes the heat transfer considerations for each design.

Hovingh, J.

1980-04-23T23:59:59.000Z

357

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

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.

Reimus, Paul W [Los Alamos National Laboratory

2010-12-08T23:59:59.000Z

358

Combined heat and mass transfer device for improving separation process  

DOE Patents (OSTI)

A two-phase small channel heat exchange matrix for providing simultaneous heat transfer and mass transfer at a single, predetermined location within a separation column, whereby the thermodynamic efficiency of the separation process is significantly improved. The small channel heat exchange matrix is comprised of a series of channels having a hydraulic diameter no greater than 5.0 mm. The channels are connected to an inlet header for supplying a two-phase coolant to the channels and an outlet header for receiving the coolant horn the channels. In operation, the matrix provides the liquid-vapor contacting surfaces within a separation column, whereby liquid descends along the exterior surfaces of the cooling channels and vapor ascends between adjacent channels within the matrix. Preferably, a perforated and concave sheet connects each channel to an adjacent channel, such that liquid further descends along the concave surfaces of the sheets and the vapor further ascends through the perforations in the sheets. The size and configuration of the small channel heat exchange matrix allows the heat and mass transfer device to be positioned within the separation column, thereby allowing precise control of the local operating conditions within the column and increasing the energy efficiency of the process.

Tran, Thanh Nhon

1997-12-01T23:59:59.000Z

359

Heat transfer and pressure drop measurements in an air/molten salt direct-contact heat exchanger  

SciTech Connect

This paper presents a comparison of experimental data with a recently published model of heat exchange in irrigated packed beds. Heat transfer and pressure drop were measured in a 150 mm (ID) column with a 610-mm bed of metal Pall rings. Molten nitrate salt and preheated air were the working fluids with a salt inlet temperature of approximately 440{degree}C and air inlet temperatures of approximately 230{degree}C. A comparison between the experimental data and the heat transfer model is made on the basis of heat transfer from the salt. For the range of air and salt flow rates tested, 0.3 to 1.2 kg/m{sup 2} s air flow and 6 to 18 kg/m{sup 2} s salt flow, the data agree with the model within 22% standard deviation. In addition, a model for the column pressure drop was validated, agreeing with the experimental data within 18% standard deviation over the range of column pressure drop from 40 to 1250 Pa/m. 25 refs., 7 figs., 2 tabs.

Bohn, M.S.

1988-11-01T23:59:59.000Z

360

Deep Eutectic Salt Formulations Suitable as Advanced Heat Transfer Fluids  

Science Conference Proceedings (OSTI)

Concentrating solar power (CSP) facilities are comprised of many miles of fluid-filled pipes arranged in large grids with reflective mirrors used to capture radiation from the sun. Solar radiation heats the fluid which is used to produce steam necessary to power large electricity generation turbines. Currently, organic, oil-based fluid in the pipes has a maximum temperature threshold of 400 °C, allowing for the production of electricity at approximately 15 cents per kilowatt hour. The DOE hopes to foster the development of an advanced heat transfer fluid that can operate within higher temperature ranges. The new heat transfer fluid, when used with other advanced technologies, could significantly decrease solar electricity cost. Lower costs would make solar thermal electricity competitive with gas and coal and would offer a clean, renewable source of energy. Molten salts exhibit many desirable heat transfer qualities within the range of the project objectives. Halotechnics developed advanced heat transfer fluids (HTFs) for application in solar thermal power generation. This project focused on complex mixtures of inorganic salts that exhibited a high thermal stability, a low melting point, and other favorable characteristics. A high-throughput combinatorial research and development program was conducted in order to achieve the project objective. Over 19,000 candidate formulations were screened. The workflow developed to screen various chemical systems to discover salt formulations led to mixtures suitable for use as HTFs in both parabolic trough and heliostat CSP plants. Furthermore, salt mixtures which will not interfere with fertilizer based nitrates were discovered. In addition for use in CSP, the discovered salt mixtures can be applied to electricity storage, heat treatment of alloys and other industrial processes.

Raade, Justin; Roark, Thomas; Vaughn, John; Bradshaw, Robert

2013-07-22T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Estimation of heat transfer in oscillating annular flow using artifical neural networks  

Science Conference Proceedings (OSTI)

In this study, the prediction of heat transfer from a surface having constant heat flux subjected to oscillating annular flow is investigated using artificial neural networks (ANNs). An experimental study is carried out to estimate the heat transfer ... Keywords: Annular duct, Artificial neural network, Heat transfer, Oscillating flow

Unal Akdag; M. Aydin Komur; A. Feridun Ozguc

2009-09-01T23:59:59.000Z

362

Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants  

Science Conference Proceedings (OSTI)

A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during experimentation.

Mathur, Anoop [Terrafore Inc.] [Terrafore Inc.

2013-08-14T23:59:59.000Z

363

Detailed parametric analyses of heat transfer in CPC solar energy collectors  

SciTech Connect

A detailed parametric analysis of heat transfer in compound parabolic concentrating solar energy collectors has been performed, using a unified model for their optical and thermophysical behaviour. The effects of angular inclination and collector acceptance angles on free convection within the cavity are presented. The circumferential variation of local Nusselt number about the absorber is determined. A convective heat transfer correlation is obtained for the average Nusselt number with respect to Grashof number that takes into account acceptance angle and angular inclination. The developed correlation is extended to truncated compound parabolic concentrators.

Eames, P.C.; Norton, B. (Univ. of Ulster (United Kingdom))

1993-04-01T23:59:59.000Z

364

Heat transfer and hydrodynamics analysis of a novel dimpled tube  

SciTech Connect

In the present investigation, heat transfer and hydrodynamics analysis of a new enhanced heat transfer tube with ellipsoidal dimples was carried out. The dimples are disposed to form a certain specified angle between the major axis of the ellipsoid and flow direction, and the direction of the major axis of each adjacent ellipsoidal dimple in the same cross-section is alternated. Experimental tests were carried out with heating water on the shell side with a constant flow rate, and cold air in the tube side with flow rates range from 1 to 55 m{sup 3}/h. The temperatures and pressures for the inlet and outlet of both sides were measured. The heat transfer and pressure drop of the new dimpled tube were investigated and compared with the results of a dimpled tube with spherical dimples and a conventional smooth tube. The computed results indicated that the Nusselt number for ellipsoidal dimpled tube and spherical dimpled tube are 38.6-175.1% and 34.1-158% higher than that for the smooth tube respectively. The friction factors of dimpled tube increase by 26.9-75% and 32.9-92% for ellipsoidal and spherical dimples compared with the smooth tube respectively. It was perceived that ellipsoidal dimple roughness accelerates transition to critical Reynolds numbers down to less than 1000. By integrated performance evaluation of (Nu{sub a}/Nu{sub s})/(f{sub a}/f{sub s}), a maximum of about 87% heat transfer enhancement with the same friction penalty could be achieved by optimize the dimpled tube design. (author)

Wang, Yu.; He, Ya-Ling; Lei, Yong-Gang; Zhang, Jie [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China)

2010-11-15T23:59:59.000Z

365

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

SciTech Connect

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

Simoneau, R.J.; Simon, F.F.

1992-01-01T23:59:59.000Z

366

An Estimation of the Bulk Transfer Coefficients for a Bare Soil Surface Using a Linear Model  

Science Conference Proceedings (OSTI)

A linear heat budget model is developed to estimate the daytime means of the bulk transfer coefficients for heat and evaporation efficiency using the daily variation of observational data. The daily variation of shortwave radiation, ground-level ...

Dai Matsushima; Junsei Kondo

1995-04-01T23:59:59.000Z

367

A Simple Formula for Estimation of the Roughness Length for Heat Transfer over Partly Vegetated Surfaces  

Science Conference Proceedings (OSTI)

A simple formula for computation of the effective roughness length z0Heff for heat transfer or rather for the parameter kB?1eff [=ln(z0Meff/z0Heff) with z0Meff = roughness length for momentum], which are needed in single-source models for evaluating ...

K. Blümel

1999-06-01T23:59:59.000Z

368

Solidification Heat Transfer Analysis of AZ91D Cast Strip by Using a ...  

Science Conference Proceedings (OSTI)

The heat transfer coefficient between the molten magnesium ally and copper roll is important to cast magnesium strip. In the present study investigate the heat ...

369

Exploring the Limits of Boiling and Evaporative Heat Transfer Using Micro/Nano Structures.  

E-Print Network (OSTI)

??This dissertation presents a study exploring the limits of phase-change heat transfer with the aim of enhancing critical heat flux (CHF) in pool boiling and… (more)

Lu, Ming-Chang

2010-01-01T23:59:59.000Z

370

Monte Carlo simulation of radiation heat transfer in arrays of fixed discrete surfaces using cell-to-cell photon transport  

DOE Green Energy (OSTI)

Radiation heat transfer in an array of fixed discrete surfaces is an important problem that is particularly difficult to analyze because of the nonhomogeneous and anisotropic optical properties involved. This article presents an efficient Monte Carlo method for evaluating radiation heat transfer in arrays of fixed discrete surfaces. This Monte Carlo model has been optimized to take advantage of the regular arrangement of surfaces often encountered in these arrays. Monte Carlo model predictions have been compared with analytical and experimental results.

Drost, M.K. (Pacific Northwest Lab., Richland, WA (United States)); Welty, J.R. (Oregon State Univ., Corvallis, OR (United States))

1992-08-01T23:59:59.000Z

371

Advanced Heat Transfer Fluids for Concentrated Solar Power (CSP)  

NLE Websites -- All DOE Office Websites (Extended Search)

Science Science Computing, Environment & Life Sciences Energy Engineering & Systems Analysis Photon Sciences Physical Sciences & Engineering Energy Frontier Research Centers Science Highlights Postdoctoral Researchers Advanced Heat Transfer Fluids for Concentrated Solar Power (CSP) Applications November 1, 2011 Tweet EmailPrint The current levelized cost of energy (LCOE) from concentrated solar power (CSP) is ~ $0.11/kWh. The U.S. Department of Energy has set goals to reduce this cost to ~$0.07/kWh with 6 hours of storage by 2015 and to ~$0.05/kWh with 16 hours of storage by 2020. To help meet these goals, scientists at Argonne National Laboratory are working to improve the overall CSP plant efficiency by enhancing the thermophysical properties of heat transfer

372

Optical techniques for fluid flow and heat transfer  

Science Conference Proceedings (OSTI)

A review is presented of optical measuring techniques employed in momentum heat and mass transfer studies. A classification is given of those techniques that are nowadays widely employed in studies to advance the understanding of transport phenomena in fluids. Techniques that employ effects caused by fluid molecules are briefly treated, and examples of measurements are given to demonstrate the kind of information that can be obtained by these techniques. Optical techniques using tracers to obtain transport information are summarized, and laser-Doppler anemometry and its application to fluid flow studies are emphasized. Applications of this technique in single-phase and two-phase flows are given that demonstrate its potential in experimental fluid mechanics and convective heat transfer studies. 63 refs.

Durst, F. (Erlangen-Nuernberg Universitaet, Erlangen (Germany, F.R.))

1990-01-01T23:59:59.000Z

373

Rocket-borne, low gravity cryogenic heat transfer experiment  

SciTech Connect

From AIAA/NSA/ASTM/IES 7th space simulation conference; Los Angeles, Calif11nia, USA (12 Nov 1973). In order to obtain steady state data on nucleate boiling heat transfer to liquid helium in a nearly zero gravity environment a rocket-borne experiment was designed, built and successfully flown. A description of the apparatus and flight is presented along with preliminary results. (auth)

Williamson, K.D. Jr.; Edeskuty, F.J.; Taylor, J.F.

1974-04-30T23:59:59.000Z

374

Nonaqueous purification of mixed nitrate heat transfer media  

DOE Patents (OSTI)

A nonaqueous, in-line method for removing carbonate and hydroxide contamination from a molten mixed sodium nitrate/potassium nitrate heat transfer salt. The method comprises dissolving a stoichiometric quantity of anhydrous Ca(NO.sub.3).sub.2 in the melt whereby an insoluble CaCO.sub.3 and Ca(OH).sub.2 precipitate is formed. The precipitate can be removed by settling, filtration or floatation techniques.

Fiorucci, Louis C. (Hamden, CT); Morgan, Michael J. (Guilford, CT)

1983-12-20T23:59:59.000Z

375

SunShot Initiative: Advanced Heat Transfer Fluids and Novel Thermal...  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Heat Transfer Fluids and Novel Thermal Storage Concepts for CSP Generation to someone by E-mail Share SunShot Initiative: Advanced Heat Transfer Fluids and Novel Thermal...

376

Heat transfer rates for filmwise, dropwise, and superhydrophobic condensation on silicon substrates  

E-Print Network (OSTI)

Condensation, a two-phase heat transfer processes, is commonly utilized in industrial systems. Condensation heat transfer can be optimized by using surfaces in which dropwise condensation (DWC) occurs, and even further ...

Hery, Travis M

2011-01-01T23:59:59.000Z

377

Heat transfer during film condensation of potassium vapor on a horizontal plate  

E-Print Network (OSTI)

The object of the investigation is to analyze the following two features of heat transfer during condensation of potassium vapor: a. Heat transfer during film condensation of a pure saturated potassium vapor on a horizontal ...

Meyrial, Paul M.

1968-01-01T23:59:59.000Z

378

Situ soil sampling probe system with heated transfer line  

DOE Patents (OSTI)

The present invention is directed both to an improved in situ penetrometer probe and to a heated, flexible transfer line. The line and probe may be implemented together in a penetrometer system in which the transfer line is used to connect the probe to a collector/analyzer at the surface. The probe comprises a heater that controls a temperature of a geologic medium surrounding the probe. At least one carrier gas port and vapor collection port are located on an external side wall of the probe. The carrier gas port provides a carrier gas into the geologic medium, and the collection port captures vapors from the geologic medium for analysis. In the transfer line, a flexible collection line that conveys a collected fluid, i.e., vapor, sample to a collector/analyzer. A flexible carrier gas line conveys a carrier gas to facilitate the collection of the sample. A system heating the collection line is also provided. Preferably the collection line is electrically conductive so that an electrical power source can generate a current through it so that the internal resistance generates heat.

Robbat, Jr., Albert (Andover, MA)

2002-01-01T23:59:59.000Z

379

Experimental study of mixed convection heat transfer in vertical helically coiled tube heat exchangers  

Science Conference Proceedings (OSTI)

In this study the mixed convection heat transfer in a coil-in-shell heat exchanger for various Reynolds numbers, various tube-to-coil diameter ratios and different dimensionless coil pitch was experimentally investigated. The experiments were conducted for both laminar and turbulent flow inside coil. Effects of coil pitch and tube diameters on shell-side heat transfer coefficient of the heat exchanger were studied. Different characteristic lengths were used in various Nusselt number calculations to determine which length best fits the data and several equations were proposed. The particular difference in this study in comparison with the other similar studies was the boundary conditions for the helical coils. The results indicate that the equivalent diameter of shell is the best characteristic length. (author)

Ghorbani, N. [School of Mechanical Engineering, University of Leeds, Leeds, England (United Kingdom); Taherian, H. [Department of Engineering Technology and Industrial Distribution, Texas A and M University, College Station, TX (United States); Gorji, M. [Department of Mechanical Engineering, Babol Noushirvani University of Technology, Babol (Iran); Mirgolbabaei, H. [Department of Mechanical Engineering, Islamic Azad University, Jouybar branch, Jouybar (Iran)

2010-10-15T23:59:59.000Z

380

Liquid-fluidized-bed heat exchanger flow distribution models  

DOE Green Energy (OSTI)

Allied Chemical Corporation at the Idaho National Engineering Laboratory is developing liquid-fluidized-bed shell-and-tube heat exchangers for geothermal applications. Sand fluidized by geothermal water on the shell side prevents scaling and increases heat transfer coefficients over conventional heat exchangers. Tests were conducted on two instrumented fluidized-bed heat exchanger models, constructed primarily of plexiglass, which differ in tube bundle orientation. One contains a horizontal bundle and the other a vertical tube bundle. Plexiglass construction allowed visual observation of flow patterns. The vertical model proved to have more uniform flow distribution and higher heat transfer coefficients than the horizontal model. The horizontal heat exchanger experienced piling on top of the tubes and areas of poor fluidization existed in the bed. Geometric considerations show that a horizontal design is more conducive to large flow rates than a vertical design. New design concepts for both vertical and horizontal assemblies and recommendations for further developmental work are presented.

Cole, L.T.; Allen, C.A.

1979-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Measurements and Predictions of the Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Exchangers  

E-Print Network (OSTI)

to the International Journal of Compact Heat Exchangers, May 2003 #12;2 Measurements and Predictions of the Heat Transfer at the Tube-Fin Junction for Louvered Fin Heat Exchangers Abstract The dominant thermal resistance for most compact heat exchangers occurs on the air side and thus a detailed understanding of air side heat

Thole, Karen A.

382

An experimental investigation of convection heat transfer to supercritical carbon dioxide in miniature tubes  

E-Print Network (OSTI)

-year research program in heat transfer and viscoelastic fluid flows, after working for some time in industry of All Sciences), Fluid Mechanics, Heat Transfer and related fluid-thermal-energy sciences; with emphases Press series Advances in Heat Transfer, Volume 19, and "Viscosity" in CRC Press' Measurement

Zhao, Tianshou

383

Molten salt as a heat transfer fluid for heating a subsurface formation  

DOE Patents (OSTI)

A heating system for a subsurface formation includes a conduit located in an opening in the subsurface formation. An insulated conductor is located in the conduit. A material is in the conduit between a portion of the insulated conductor and a portion of the conduit. The material may be a salt. The material is a fluid at operating temperature of the heating system. Heat transfers from the insulated conductor to the fluid, from the fluid to the conduit, and from the conduit to the subsurface formation.

Nguyen, Scott Vinh (Houston, TX); Vinegar, Harold J. (Bellaire, TX)

2010-11-16T23:59:59.000Z

384

A Model of Heat Conduction  

E-Print Network (OSTI)

We define a deterministic ``scattering'' model for heat conduction which is continuous in space, and which has a Boltzmann type flavor, obtained by a closure based on memory loss between collisions. We prove that this model has, for stochastic driving forces at the boundary, close to Maxwellians, a unique non-equilibrium steady state.

Collet, Pierre

2008-01-01T23:59:59.000Z

385

The multiple absorption coefficient zonal method (MACZM), an efficient computational approach for the analysis of radiative heat transfer in multidimensional inhomogeneous nongray media  

E-Print Network (OSTI)

of Radiative Heat Transfer, the P-3 Approximation”, AIAAMedia”, Journal of Heat Transfer, Vol. 109, No. 3 (1987),Media”, Numerical Heat Transfer, Part B, Fundamentals, Vol.

Yuen, W W

2006-01-01T23:59:59.000Z

386

Determination of a time-dependent heat transfer coefficient from non-standard boundary measurements  

Science Conference Proceedings (OSTI)

In this paper the determination of the time-dependent heat transfer coefficient in one-dimensional transient heat conduction from a non-standard boundary measurement is investigated. For this inverse nonlinear ill-posed problem the uniqueness of the ... Keywords: Boundary element method, Heat conduction, Heat transfer coefficient, Inverse problem

T. T. M. Onyango; D. B. Ingham; D. Lesnic; M. Slodi?ka

2009-01-01T23:59:59.000Z

387

Heat transfer mechanism with thin filaments including ceramic high temperature heat exchanger  

DOE Patents (OSTI)

A radiative heat transfer mechanism in a furnace having burners through which pulverized coal and air are burned producing combustion gases and contaminants. A plurality of elongated conduits are positioned inside the furnace proximate to the burners generally parallel to the flow of combustion gases in the furnace. A plurality of thin filaments are inside each of the elongated hollow conduits, the filaments having diameters in the range of from about 1 micrometer to about 1,000 micrometers and having an infrared radiation cross-section sufficient to cause the filaments to heat upon exposure to infrared radiation. Blower mechanism is associated with the elongated conduits for limiting the amount of soot and ash which deposit on the conduits to preserve the radiative and convective transfer of heat energy from the combustion gases to the conduits.

Im, Kwan H. (Naperville, IL); Ahluwalia, Rajesh K. (Burr Ridge, IL)

1994-01-01T23:59:59.000Z

388

Heat transfer mechanism with thin filaments including ceramic high temperature heat exchanger  

DOE Patents (OSTI)

A radiative heat transfer mechanism in a furnace is described having burners through which pulverized coal and air are burned producing combustion gases and contaminants. A plurality of elongated conduits are positioned inside the furnace proximate to the burners generally parallel to the flow of combustion gases in the furnace. A plurality of thin filaments are inside each of the elongated hollow conduits, the filaments having diameters in the range of from about 1 micrometer to about 1,000 micrometers and having an infrared radiation cross-section sufficient to cause the filaments to heat upon exposure to infrared radiation. Blower mechanism is associated with the elongated conduits for limiting the amount of soot and ash which deposit on the conduits to preserve the radiative and convective transfer of heat energy from the combustion gases to the conduits. 7 figs.

Im, K.H.; Ahluwalia, R.K.

1994-10-18T23:59:59.000Z

389

Heat transfer in porous media with fluid phase changes  

DOE Green Energy (OSTI)

A one-dimensional experimental apparatus was built to study the heat pipe phenomenon. Basically, it consists of a 25 cm long, 2.5 cm I.D. Lexane tube packed with Ottawa sand. The two ends of the tube were subjected to different tempratures, i.e., one above the boiling temperature and the other below. The tube was well insulated so that a uniform one-dimensional heat flux could pass through the sand pack. Presence of the heat pipe phenomenon was confirmed by the temperature and saturation profiles of the sand pack at the final steady state condition. A one-dimensional steady state theory to describe the experiment has been developed which shows the functional dependence of the heat pipe phenomenon on liquid saturation gradient, capillary pressure, permeability, fluid viscosity, latent heat, heat flux and gravity. Influence of the heat pipe phenomenon on wellbore heat losses was studied by use of a two-phase two-dimensional cylindrical coordinate computer model.

Su, H.J.

1981-06-01T23:59:59.000Z

390

The effect of periodic unsteady wakes on boundary layer transition and heat transfer on a curved plate.  

E-Print Network (OSTI)

??The effect of unsteady periodic wakes on heat transfer and boundary layer transition was investigated on a constant curvature heat transfer curved plate in a… (more)

Wright, Lance Cole

2012-01-01T23:59:59.000Z

391

NUMERICAL SIMULATION OF HEAT TRANSFER AND PRESSURE DROP IN PLATE HEAT EXCHANGERS USING FLUENT AS CFD TOOL.  

E-Print Network (OSTI)

??Corrugated walls are commonly used as passive devices for heat and mass transfer enhancement, being most effective in applications operated at transitional and turbulent Reynolds… (more)

EGEREGOR, DAFE

2008-01-01T23:59:59.000Z

392

Thermal correction to the Casimir force, radiative heat transfer, and an experiment  

E-Print Network (OSTI)

The low-temperature asymptotic expressions for the Casimir interaction between two real metals described by Leontovich surface impedance are obtained in the framework of thermal quantum field theory. It is shown that the Casimir entropy computed using the impedance of infrared optics vanishes in the limit of zero temperature. By contrast, the Casimir entropy computed using the impedance of the Drude model attains at zero temperature a positive value which depends on the parameters of a system, i.e., the Nernst heat theorem is violated. Thus, the impedance of infrared optics withstands the thermodynamic test, whereas the impedance of the Drude model does not. We also perform a phenomenological analysis of the thermal Casimir force and of the radiative heat transfer through a vacuum gap between real metal plates. The characterization of a metal by means of the Leontovich impedance of the Drude model is shown to be inconsistent with experiment at separations of a few hundred nanometers. A modification of the impedance of infrared optics is suggested taking into account relaxation processes. The power of radiative heat transfer predicted from this impedance is several times less than previous predictions due to different contributions from the transverse electric evanescent waves. The physical meaning of low frequencies in the Lifshitz formula is discussed. It is concluded that new measurements of radiative heat transfer are required to find out the adequate description of a metal in the theory of electromagnetic fluctuations.

V. B. Bezerra; G. Bimonte; G. L. Klimchitskaya; V. M. Mostepanenko; C. Romero

2007-08-18T23:59:59.000Z

393

Heat Transfer and Reconnection Diffusion in Turbulent Magnetized Plasmas  

E-Print Network (OSTI)

It is well known that magnetic fields constrain motions of charged particles, impeding the diffusion of charged particles perpendicular to magnetic field direction. This modification of transport processes is of vital importance for a wide variety of astrophysical processes including cosmic ray transport, transfer of heavy elements in the interstellar medium, star formation etc. Dealing with these processes one should keep in mind that in realistic astrophysical conditions magnetized fluids are turbulent. In this review we single out a single transport process, namely, heat transfer and consider how it occurs in the presence of the magnetized turbulence. We show that the ability of magnetic field lines to constantly change topology and connectivity is at the heart of the correct description of the 3D magnetic field stochasticity in turbulent fluids. This ability is ensured by fast magnetic reconnection in turbulent fluids and puts forward the concept of reconnection diffusion at the core of the physical pictu...

Lazarian, A

2011-01-01T23:59:59.000Z

394

SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer  

NLE Websites -- All DOE Office Websites (Extended Search)

High Operating Temperature Liquid High Operating Temperature Liquid Metal Heat Transfer Fluids to someone by E-mail Share SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on Facebook Tweet about SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on Twitter Bookmark SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on Google Bookmark SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on Delicious Rank SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on Digg Find More places to share SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer Fluids on AddThis.com... Concentrating Solar Power Systems Components Competitive Awards

395

Low-melting point inorganic nitrate salt heat transfer fluid  

DOE Patents (OSTI)

A low-melting point, heat transfer fluid made of a mixture of four inorganic nitrate salts: 9-18 wt % NaNO.sub.3, 40-52 wt % KNO.sub.3, 13-21 wt % LiNO.sub.3, and 20-27 wt % Ca(NO.sub.3).sub.2. These compositions can have liquidus temperatures less than 100 C; thermal stability limits greater than 500 C; and viscosity in the range of 5-6 cP at 300 C; and 2-3 cP at 400 C.

Bradshaw, Robert W. (Livermore, CA); Brosseau, Douglas A. (Albuquerque, NM)

2009-09-15T23:59:59.000Z

396

Grid-independent Issue in Numerical Heat Transfer  

E-Print Network (OSTI)

Grid independent is associated with the accuracy or even rationality of numerical results. This paper takes two-dimensional steady heat transfer for example to reveal the effect of grid resolution on numerical results. The law of grid dependence is obtained and a simple mathematical formula is presented. The production acquired here can be used as the guidance in choosing grid density in numerical simulation and get exact grid independent value without using infinite fine grid. Through analyzing grid independent, we can find the minimum number of grid cells that is needed to get grid-independent results. Such strategy can save computational resource while ensure a rational computational result.

Yao Wei; Wang Jian; Liao Guangxuan

2006-09-25T23:59:59.000Z

397

Heat and mass transfer in packed bed liquid desiccant regenerators -- An experimental investigation  

Science Conference Proceedings (OSTI)

Liquid desiccant cooling can provide control of temperature and humidity, while at the same time lowering the electrical energy requirement for air conditioning. Since the largest energy requirement associated with desiccant cooling is low temperature heat for desiccant regeneration, the regeneration process greatly influences the overall system performance. Therefore, the effects of variables such as air and desiccant flow rates, air temperature and humidity, desiccant temperature and concentration, and the area available for heat and mass transfer on the regeneration process are of great interest. Due to the complexity of the regeneration process, which involves simultaneous heat and mass transfer, theoretical modeling must be verified by experimental studies. However, a limited number of experimental studies are reported in the literature. This paper presents results from a detailed experimental investigation of the heat and mass transfer between a liquid desiccant (triethylene glycol) and air in a packed bed regenerator using high liquid flow rates. To regenerate the desiccant, it is heated to temperatures readily obtainable from flat-plate solar collectors. A high performance packing that combines good heat and mass transfer characteristics with low pressure drop is used. The rate of water evaporation, as well as the effectiveness of the regeneration process is assessed based on the variables listed above. Good agreement is shown to exist between the experimental findings and predictions from finite difference modeling. In addition, the findings in the present study are compared to findings previously reported in the literature. Also, the results presented here characterize the important variables that impact the system design.

Martin, V.; Goswami, D.Y.

1999-08-01T23:59:59.000Z

398

Heat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical delta winglets  

E-Print Network (OSTI)

Heat transfer augmentation along the tube wall of a louvered fin heat exchanger using practical surface of louvered fin heat exchangers. It is shown that delta winglets placed on louvered fins produce Elsevier Ltd. All rights reserved. Keywords: Compact heat exchanger; Vortex generator; Louvered fins 1

Thole, Karen A.

399

Heat and mass transfer in unsaturated porous media. Final report  

DOE Green Energy (OSTI)

A preliminary study of heat and water transport in unsaturated porous media is reported. The project provides background information regarding the feasibility of seasonal thermal energy storage in unconfined aquifers. A parametric analysis of the factors of importance, and an annotated bibliography of research findings pertinent to unconfined aquifer thermal energy storage (ATES) are presented. This analysis shows that heat and mass transfer of water vapor assume dominant importance in unsaturated porous media at elevated temperature. Although water vapor fluxes are seldom as large as saturated medium liquid water fluxes, they are important under unsaturated conditions. The major heat transport mechanism for unsaturated porous media at temperatures from 50 to 90/sup 0/C is latent heat flux. The mechanism is nonexistent under saturated conditions but may well control design of unconfined aquifer storage systems. The parametric analysis treats detailed physical phenomena which occur in the flow systems study and demonstrates the temperature and moisture dependence of the transport coefficients of importance. The question of design of an unconfined ATES site is also addressed by considering the effects of aquifer temperature, depth to water table, porous medium flow properties, and surface boundary conditions. Recommendations are made for continuation of this project in its second phase. Both scientific and engineering goals are considered and alternatives are presented.

Childs, S.W.; Malstaff, G.

1982-02-01T23:59:59.000Z

400

Effect of translucence of engineering ceramics on heat transfer in diesel engines  

DOE Green Energy (OSTI)

This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.

Wahiduzzaman, S.; Morel, T. (Integral Technologies, Inc., Westmont, IL (United States))

1992-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Effect of translucence of engineering ceramics on heat transfer in diesel engines. Final report  

DOE Green Energy (OSTI)

This report describes the experimental portion of a broader study undertaken to assess the effects of translucence of ceramic materials used as thermal barrier coatings in diesel engines. In an earlier analytical work a parametric study was performed, varying several radiative properties over ranges typical of engineering ceramics, thereby identifying the most important radiative properties and their impact on in-cylinder heat transfer. In the current study these properties were experimentally determined for several specific zirconia coatings considered for thermal barrier applications in diesel engines. The methodology of this study involved formulation of a model capable of describing radiative transfer through a semitransparent medium as a function of three independent model parameters, ie, absorption coefficient, scattering coefficient and refractive index. For the zirconia-based ceramics investigated in this study, it was concluded that for usual coating thicknesses (1.5--2.5 mm) these ceramics are optically thick and hence, are effective as radiative heat transfer barriers. These ceramics possess high scattering coefficients and low absorption coefficients causing them to be highly reflective (60-80%) in the spectral region where thermal radiation is important. The performance of the investigated ceramics and the mechanism of heat transfer were found to depend on surface condition, specifically on soot deposition. Thus, to insure the optimum thermal barrier operation for either clean or heavily sooted surfaces, a ceramic material with high scattering coefficient provides the best choice.

Wahiduzzaman, S.; Morel, T. [Integral Technologies, Inc., Westmont, IL (United States)

1992-04-01T23:59:59.000Z

402

TRANSIENT HEAT TRANSFER ANALYSIS FOR SRS RADIOACTIVE TANK OPERATION  

SciTech Connect

The primary objective of the present work is to perform a heat balance study for type-I waste tank to assess the impact of using submersible mixer pumps during waste removal. The temperature results calculated by the model will be used to evaluate the temperatures of the slurry waste under various tank operating conditions. A parametric approach was taken to develop a transient model for the heat balance study for type-I waste tanks such as Tank 11, during waste removal by SMP. The tank domain used in the present model consists of two SMP?s for sludge mixing, one STP for the waste removal, cooling coil system with 36 coils, and purge gas system. The sludge waste contained in Tank 11 also has a decay heat load of about 43 W/m{sup 3} mainly due to the emission of radioactive gamma rays. All governing equations were established by an overall energy balance for the tank domain, and they were numerically solved. A transient heat balance model used single waste temperature model, which represents one temperature for the entire waste liquid domain contained in the tank at each transient time.

Lee, S.

2013-06-27T23:59:59.000Z

403

Forced flow supercritical helium in a closed heat transfer loop subjected to pulsed heat loads  

Science Conference Proceedings (OSTI)

The superconducting magnets of the tokamak JT-60SA are cooled by means of forced flows of supercritical helium at 4.4 K and 0.5 MPa. The closed loops transfer heat from the magnets to the refrigerator through heat exchangers immersed into a saturated liquid helium bath. An experimental loop was designed to represent a 1/20 scaled down mock-up of JT-60SA central solenoid cooling circuits. This design for keeping the same transit times in the helium circuits

2012-01-01T23:59:59.000Z

404

Modeling of coupled heat transfer and reactive transport processes in porous media: Application to seepage studies at Yucca Mountain, Nevad a  

E-Print Network (OSTI)

Fractured Rock of Yucca Mountain, Nevada: Heterogeneity andfractured rocks of Yucca Mountain have been extensivelyHydrothermal Flow at Yucca Mountain, Part I: Modeling and

Mukhopadhyay, S.; Sonnenthal, E.L.; Spycher, N.

2008-01-01T23:59:59.000Z

405

The effect of a magnetic field on heat transfer in a slotted channel  

SciTech Connect

The results of numerical and experimental studies of liquid metal heat transfer in slotted channels in a transverse magnetic field are presented. Test results showed an improvement in heat transfer in a straight channel at low and moderate interaction parameter, N. The Nusselt number at small N (around 120) was up to 2 times higher than in turbulent flow without a magnetic field, Peclet number being equal. This effect of heat transfer enhancement is caused by the generation and development of large scale velocity fluctuations in the near heated wall area. Qualitative and quantitative correlations between heat transfer and velocity fluctuation characteristics are presented.

Evtushenko, I.A.; Kirillov, I.R.; Sidorenkov, S.S. [D.V. Efremov Scientific Research Institute of Electrophysical Apparatus, St. Petersburg (Russian Federation); Hua, T.Q.; Reed, C.B. [Argonne National Lab., IL (United States)

1994-07-01T23:59:59.000Z

406

Analysis of the adsorption process and of desiccant cooling systems: a pseudo- steady-state model for coupled heat and mass transfer. [DESSIM, DESSIM2, DESSIM4  

DOE Green Energy (OSTI)

A computer model to simulate the adiabatic adsorption/desorption process is documented. Developed to predict the performance of desiccant cooling systems, the model has been validated through comparison with experimental data for single-blow adsorption and desorption. A literature review on adsorption analysis, detailed discussions of the adsorption process, and an initial assessment of the potential for performance improvement through advanced component development are included.

Barlow, R.S.

1982-12-01T23:59:59.000Z

407

Conjugate Effects on Steady Laminar Natural Convection Heat Transfer in Vertical Eccentric Annuli  

E-Print Network (OSTI)

Local heat flux on outer interface at channel exit i Index for bi-polar grid in the -directionConjugate Effects on Steady Laminar Natural Convection Heat Transfer in Vertical Eccentric Annuli University of Petroleum and Minerals, Dhahran, Saudi Arabia Combined conduction-free convection heat transfer

Jamal, Ahmad

408

Heating surface material’s effect on subcooled flow boiling heat transfer of R134a  

Science Conference Proceedings (OSTI)

In this study, subcooled flow boiling of R134a on copper (Cu) and stainless steel (SS) heating surfaces was experimentally investigated from both macroscopic and microscopic points of view. By utilizing a high-speed digital camera, bubble growth rate, bubble departure size, and nucleation site density, were able to be observed and analyzed from the microscopic point of view. Macroscopic characteristics of the subcooled flow boiling, such as heat transfer coefficient, were able to be measured as well. Experimental results showed that there are no obvious difference between the copper and the stainless surface with respect to bubble dynamics, such as contact angle, growth rate and departure size. On the contrary, the results clearly showed a trend that the copper surface had a better performance than the stainless steel surface in terms of heat transfer coefficient. It was also observed that wall heat fluxes on both surfaces were found highly correlated with nucleation site density, as bubble hydrodynamics are similar on these two surfaces. The difference between these two surfaces was concluded as results of different surface thermal conductivities.

Ling Zou; Barclay G. Jones

2012-11-01T23:59:59.000Z

409

Numerical study of high heat ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b  

E-Print Network (OSTI)

in saturated pool boiling. In this model the analysis of heat conduction within the heater is added on the heater surface itself [10]. Bhat et al. [11] put forward a theoretical model of macrolayer formation to their model and ob- tained the simulated boiling curve of water. In addition, they compared Haramura and Katto

Maruyama, Shigeo

410

A model for laboratory tech transfer investment  

Science Conference Proceedings (OSTI)

A simple model has been developed to address a pragmatic question: What fraction of its research and development budget should a national laboratory devote to enhancing technology in the private sector? In dealing with lab-wide budgets in an aggregate sense, the model uses three parameters - fraction of lab R&D transferable to industry, transfer efficiency and payback to laboratory missions - to partition fixed R&D resources between technology transfer and core missions. It is a steady-state model in that the transfer process is assumed to work in equilibrium with technology generation. The results presented should be of use to those engaged in managing and overseeing federal laboratory technology transfer activities.

Otey, G.R.; Carson, C.C.; Bomber, T.M.; Rogers, J.D.

1994-06-01T23:59:59.000Z

411

A methodology to assess the influence of local wind conditions and building orientation on the convective heat transfer at building surfaces  

Science Conference Proceedings (OSTI)

Information on the statistical mean convective heat transfer coefficient (CHTC"S"M) for a building surface, which represents the temporally-averaged CHTC over a long time span (e.g. the lifetime of the building), could be useful for example for the optimisation ... Keywords: Building facade, Building orientation, CFD, Convective heat transfer coefficient, Low-Reynolds number modelling, RANS, Wind climate

Thijs Defraeye; Jan Carmeliet

2010-12-01T23:59:59.000Z

412

Flow and heat transfer in a curved pipe with periodically varying curvature  

SciTech Connect

A numerical analysis is carried out for the study of the flow and heat transfer for a laminar flow in a pipe with periodically varying finite (not very small) curvature. The effects of the flow rate (Re), the Prandtl number (Pr), the pipe-period ({kappa}) and the pipe-amplitude (a) on the heat transfer ratio (heat transfer of curved pipe to straight pipe) are studied. The results show that an increase in the amplitude and/or a decrease in the wavelength of a periodic wavy pipe can enhance the heat transfer rate significantly. The ratio of the heat transfer ratio to the friction ratio is greater than one which means a net benefit of heat transfer enhancement.

Yang, R.; Chang, S.F.; Wu, W.

2000-01-01T23:59:59.000Z

413

A method of correlating heat transfer data for surface boiling of liquids  

E-Print Network (OSTI)

A method based an a logical uxplanation of the meani of beat transfer associated with the boiling process is presented for correlating heat transfer data for nucleate boiling of liquids for the case of pool boiling. Tbe ...

Rohsenow, Warren M.

1951-01-01T23:59:59.000Z

414

Casting-chill interface heat transfer during solidification of an aluminum alloy  

SciTech Connect

Unidirectional solidification tests on an aluminum alloy were conducted with a computer-controlled instrumented rig. The alloys employed in this study were poured into isolated ingot molds (made of recrystallized alumina and covered with ceramic fiber) placed on top of a steel plate, coated either with a graphite- or ceramic-based paint in order to avoid sticking or the material. Thermal evolution during the test was captured by type-K thermocouples placed at different positions in both the ingot and the plate. The bottom surface of the plate was either cooled with water or left to cool in air. The heat-transfer coefficients across the aluminum-steel interface were evaluated by means of a finite-difference model. It was concluded that the heat-transfer rate depends on the conditions at the interface, such as the type of coating used to protect the plate, and the solidification reactions occurring on the aluminum during its solidification.

Velasco, E.; Cano, S.; Valtierra, S.; Mojica, J.F. [Corporativo Nemak, S.A. de C.V., Garcia (Mexico); Talamantes, J.; Colas, R. [Univ. Autonoma de Nuevo Leon (Mexico). Facultad de Ingenieria Mecanica y Electrica

1999-08-01T23:59:59.000Z

415

Experimental study of the heat and mass transfer in a packed bed liquid desiccant air dehumidifier  

Science Conference Proceedings (OSTI)

Desiccant cooling systems have the ability to provide efficient humidity and temperature control while reducing the electrical energy requirement for air conditioning as compared to a conventional system. Naturally, the desiccant air dehumidification process greatly influences the overall performance of the desiccant system. Therefore, the effects of variables such as air and desiccant flow rates, air temperature and humidity, desiccant temperature and concentration, and the area available for heat and mass transfer are of great interest. Due to the complexity of the dehumidification process, theoretical modeling relies heavily upon experimental studies. However, a limited number of experimental studies are reported in the literature. This paper presents results from a detailed experimental investigation of the heat and mass transfer between a liquid desiccant (triethylene glycol) and air in a packed bed absorption tower using high liquid flow rates. A high performance packing that combines good heat and mass transfer characteristics with low pressure drop is used. The rate of dehumidification, as well as the effectiveness of the dehumidification process are assessed based on the variables listed above. Good agreement is shown to exist between the experimental findings and predictions from finite difference modeling. In addition, a comparison between the findings in the present study and findings previously reported in the literature is made. The results obtained from this study make it possible to characterize the important variables which impact the system design.

Oeberg, V.; Goswami, D.Y. [Univ. of Florida, Gainesville, FL (United States)

1998-11-01T23:59:59.000Z

416

HEAT TRANSFER IN POROUS MEDIA WITH FLUID PHASE CHANGES  

E-Print Network (OSTI)

Cotter, T. P. : "Theory of Heat Pipe," Report No. LA-3246-L. : "Two Component Heat Pipes, It Propress in Astronauticsthe successful. The 'heat pipe ph periments were quite

Su, Ho-Jeen.

2010-01-01T23:59:59.000Z

417

Heat transfer in inertial confinement fusion reactor systems  

SciTech Connect

The transfer of energy produced by the interaction of the intense pulses of short-ranged fusion microexplosion products with materials is one of the most difficult problems in inertially-confined fusion (ICF) reactor design. The short time and deposition distance for the energy results in local peak power densities on the order of 10/sup 18/ watts/m/sup 3/. High local power densities may cause change of state or spall in the reactor materials. This will limit the structure lifetimes for ICF reactors of economic physical sizes, increasing operating costs including structure replacement and radioactive waste management. Four basic first wall protection methods have evolved: a dry-wall, a wet-wall, a magnetically shielded wall, and a fluid wall. These approaches are distinguished by the way the reactor wall interfaces with fusion debris as well as the way the ambient cavity conditions modify the fusion energy forms and spectra at the first wall. Each of these approaches requires different heat transfer considerations.

Hovingh, J.

1979-05-14T23:59:59.000Z

418

The Influence of Proposed Repository Thermal Load on Multiphase Flow and Heat Transfer in the Unsaturated Zone of Yucca Mountain  

E-Print Network (OSTI)

22]. Fluid flow and heat-transfer processes in a two-phase,processes associated with multiphase flow and heat transferprocesses has also motivated development of fluid flow and heat transfer

Wu, Y.-S.; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, G.S.

2006-01-01T23:59:59.000Z

419

Heat and mass transfer in deep fat frying of breaded chicken nuggets.  

E-Print Network (OSTI)

??This study presents techniques that can be applied to optimize the quality of coated fried chicken nuggets. Heat and mass transfer during deep fat frying… (more)

Wang, Yunfeng, 1970-

2005-01-01T23:59:59.000Z

420

Heat transfer characteristics of a two-phase, air-water direct contact evaporator.  

E-Print Network (OSTI)

??The purpose of the research was to carry out an experimental and theoretical investigation of the heat transfer on a direct contact column for desalination… (more)

Zanette, Luca

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Effect of TiO2 on the Conduction Heat Transfer of Mold Flux  

Science Conference Proceedings (OSTI)

Symposium, 2nd International Symposium on High-Temperature Metallurgical Processing. Presentation Title, Effect of TiO2 on the Conduction Heat Transfer of

422

Flow fields and heat transfer of liquid falling film on horizontal cylinders.  

E-Print Network (OSTI)

??A liquid film flowing over horizontal cylinders is of great importance as a high rate of heat transfer exists between the falling liquid film and… (more)

Jafar, Farial A

2011-01-01T23:59:59.000Z

423

Design and evaluation of heat transfer fluids for direct immersion cooling of electronic systems .  

E-Print Network (OSTI)

??Comprehensive molecular design was used to identify new heat transfer fluids for direct immersion phase change cooling of electronic systems. Four group contribution methods for… (more)

Harikumar Warrier, Pramod Kumar Warrier

2012-01-01T23:59:59.000Z

424

Impingement cooling and heat transfer measurement using transient liquid crystal technique.  

E-Print Network (OSTI)

??A heat transfer study on jet impingement cooling is presented. The study focuses on the effect of impingement jet flow rate, jet angle, and flow… (more)

Huang, Yizhe

2012-01-01T23:59:59.000Z

425

Dynamic wetting and heat transfer behaviour of aluminium droplets impinging and solidifying on copper substrates.  

E-Print Network (OSTI)

??The present work describes an experimental set-up built to simulate dynamic wetting and heat transfer occurring in many rapid solidification processes. Tests were performed with… (more)

Leboeuf, Sébastien

2004-01-01T23:59:59.000Z

426

Heat transfer to and from a reversible thermosiphon placed in porous media.  

E-Print Network (OSTI)

??The primary focus of this work is an assessment of heat transfer to and from a reversible thermosiphon imbedded in porous media. The interest in… (more)

Kekelia, Bidzina

2012-01-01T23:59:59.000Z

427

The Study of Heat and Mass Transfer In The Generator For an Absorption Air Conditioning System.  

E-Print Network (OSTI)

??This thesis is aimed to study the heat and mass transfer performance of a generator for the absorption cooling system. Both aqueous lithium bromide (LiBr)… (more)

Hsu, Yu-lien

2012-01-01T23:59:59.000Z

428

Theoretical analysis of heat transfer in semi-infinite aquifer  

SciTech Connect

A simple model for temperature within an unconfined semi-infinite aquifer is proposed with ground water flowing perpendicular to heat flow. The authors results show that it is possible to correct the observed geothermal gradient in order to obtain the undisturbed gradient, to identify the portion of the aquifer where the perturbation produced by water motion is unimportant, and to recognize the depth and distance from the recharge zone where water temperature is higher and can be exploited for low enthalpy utilization.

Mongelli, F. (Univ. di Bari (Italy). Dipt. di Geologia e Geofisica)

1994-04-01T23:59:59.000Z

429

W-12: Determination of Interfacial Heat Transfer and Air-gap ...  

Science Conference Proceedings (OSTI)

It is predicted for the Nickel-based alloy when the air-gap is below 0.3mm heat conduction is the dominant heat transfer process; above 0.3mm radiation is the ...

430

ADVANCES IN MODELING OF GROUND-SOURCE HEAT  

E-Print Network (OSTI)

] K. C. Toh, X. Y. Chen, and J. C. Chai, "Numerical computation of fluid flow and heat transfer journal and conference papers. His current research interests include heat transfer and fluid-flow to substantially increase the heat transfer coefficient when a fluid is passing through microchannels. Heat sinks

431

Program on Technology Innovation: Applications of Nanofluids to Enhance Heat Transfer in Nuclear Reactors  

Science Conference Proceedings (OSTI)

Advances in electronics and heat transfer systems require an improved energy removal rate from heated surfaces. Nanofluidsengineered colloidal dispersions of nano-size (1100 nm) particles in common fluids such as waterhave been found to enhance heat transfer properties. Because the primary mechanism of critical heat flux (CHF) enhancement results from the surface deposition of nanoparticles, nanofluids can be applied in two ways: through direct use as an advanced coolant and as a process coolant for in s...

2009-11-17T23:59:59.000Z

432

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients  

DOE Green Energy (OSTI)

Effect of Mixed Working Fluid Composition on Binary Cycle Condenser Heat Transfer Coefficients Dan Wendt, Greg Mines Idaho National Laboratory The use of mixed working fluids in binary power plants can provide significant increases in plant performance, provided the heat exchangers are designed to take advantage of these fluids non-isothermal phase changes. In the 1980's testing was conducted at DOE's Heat Cycle Research Facility (HCRF) where mixtures of different compositions were vaporized at supercritical pressures and then condensed. This testing had focused on using the data collected to verify that Heat Transfer Research Incorporated (HTRI) codes were suitable for the design of heat exchangers that could be used with mixtures. The HCRF data includes mixture compositions varying from 0% to 40% isopentane and condenser tube orientations of 15{sup o}, 60{sup o}, and 90{sup o} from horizontal. Testing was performed over a range of working fluid and cooling fluid conditions. Though the condenser used in this testing was water cooled, the working fluid condensation occurred on the tube-side of the heat exchanger. This tube-side condensation is analogous to that in an air-cooled condenser. Tube-side condensing heat transfer coefficient information gleaned from the HCRF testing is used in this study to assess the suitability of air-cooled condenser designs for use with mixtures. Results of an air-cooled binary plant process model performed with Aspen Plus indicate that that the optimal mixture composition (producing the maximum net power for the scenario considered) is within the range of compositions for which data exist. The HCRF data is used to assess the impact of composition, tube orientation, and process parameters on the condensing heat transfer coefficients. The sensitivity of the condensing coefficients to these factors is evaluated and the suitability of air-cooled condenser designs with mixtures is assessed. This paper summarizes the evaluation of the HCRF data and discusses the next steps in the project evaluation of air-cooled condenser designs that can take advantage of the performance gains possible with these fluids.

Dan Wendt; Greg Mines

2011-10-01T23:59:59.000Z

433

Heat transfer and pressure drop for air flow through enhanced passages. Final report  

SciTech Connect

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

Obot, N.T.; Esen, E.B.

1992-06-01T23:59:59.000Z

434

Heat transfer and pressure drop for air flow through enhanced passages  

SciTech Connect

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

Obot, N.T.; Esen, E.B.

1992-06-01T23:59:59.000Z

435

Steady-state heat transfer in an inverted U-tube steam generator  

SciTech Connect

Experimental results are presented involving U-tube steam generator tube bundle local heat transfer and fluid conditions during steady-state, full-power operations performed at high temperatures and pressures with conditions typical of a pressurized water reactor (15.0 MPa primary pressure, 600 K hot-leg fluid temperatures, 6.2 MPa secondary pressure). The MOD-2C facility represents the state-of-the-art in measurement of tube local heat transfer data and average tube bundle secondary fluid density at several elevations, which allows an estimate of the axial heat transfer and void distributions during steady-state and transient operations. The method of heat transfer data reduction is presented and the heat flux, secondary convective heat transfer coefficient, and void fraction distributions are quantified for steady-state, full-power operations.

Boucher, T.J.

1986-01-01T23:59:59.000Z

436

Steady-state heat transfer in an inverted U-tube steam generator  

Science Conference Proceedings (OSTI)

Experimental results are presented involving U-tube steam generator tube bundle local heat transfer and fluid conditions during stead-state, full-power operations performed at high temperatures and pressures with conditions typical of a pressurized water reactor (15.0 MPa primary pressure, 600 K steam generator inlet plenum fluid temperatures, 6.2 MPa secondary pressure). The Semiscale (MOD-2C facility represents the state-of-the-art in measurement of tube local heat transfer data and average tube bundle secondary fluid density at several elevations, which allows an estimate of the axial heat transfer and void distributions during steady-state and transient operations. The method of heat transfer data reduction is presented and the heat flux, secondary convective heat transfer coefficient, and void fraction distributions are quantified for steady-state, full-power operations.

Boucher, T.J.

1987-01-01T23:59:59.000Z

437

USING LIGA BASED MICROFABRICATION TO IMPROVE OVERALL HEAT TRANSFER EFFICIENCY OF PRESSURIZED WATER REACTOR: I. Effects of Different Micro Pattern on Overall Heat Transfer.  

SciTech Connect

The Pressurized Water Reactors (PWRs in Figure 1) were originally developed for naval propulsion purposes, and then adapted to land-based applications. It has three parts: the reactor coolant system, the steam generator and the condenser. The Steam generator (a yellow area in Figure 1) is a shell and tube heat exchanger with high-pressure primary water passing through the tube side and lower pressure secondary feed water as well as steam passing through the shell side. Therefore, a key issue in increasing the efficiency of heat exchanger is to improve the design of steam generator, which is directly translated into economic benefits. The past research works show that the presence of a pin-fin array in a channel enhances the heat transfer significantly. Hence, using microfabrication techniques, such as LIGA, micro-molding or electroplating, some special microstructures can be fabricated around the tubes in the heat exchanger to increase the heat-exchanging efficiency and reduce the overall size of the heat-exchanger for the given heat transfer rates. In this paper, micro-pin fins of different densities made of SU-8 photoresist are fabricated and studied to evaluate overall heat transfer efficiency. The results show that there is an optimized micro pin-fin configuration that has the best overall heat transfer effects.

Zhang, M.; Ibekwe, S.; Li, G.; Pang, S.S.; and Lian, K.

2006-07-01T23:59:59.000Z

438

Heat Pump Water Heating Modeling in EnergyPlus  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Heat Pump Water Heater Modeling Heat Pump Water Heater Modeling in EnergyPlus Building America Residential Energy Efficiency Stakeholder Meeting Eric Wilson Craig Christensen March 1, 2012 2 Modeling Issues Results Motivation Heat Pump Water Heater Modeling... 3 Gap: Existing analysis tools cannot accurately model HPWHs with reasonable runtime. 4 What have we achieved so far? Laboratory Evaluations 14 x Field Monitoring 5 Closing the Gap Laboratory Evaluations 6 sec timestep hourly timestep 14 x Field Monitoring CARB 6 Why is modeling important? * Performance varies: Can't just use EF * System interaction o HPWH affects building heating and cooling o Space conditions affect HPWH performance 7 Modeling Goals * Manage Risks o Accuracy o Run time o Occupant satisfaction * Flexibility to explore the effects of:

439

Two-dimensional computational fluid dynamics and conduction simulations of heat transfer in window frames with internal cavities - Part 1: Cavities only  

E-Print Network (OSTI)

of heat fluxes from CFD and conduction simulations for theapproach to solve the conduction heat-transfer equation. TheFluid Dynamics and Conduction Simulations of Heat Transfer

Gustavsen, Arild; Kohler, Christian; Arasteh, Dariush; Curcija, Dragan

2003-01-01T23:59:59.000Z

440

FEHMN 1.0: Finite element heat and mass transfer code; Revision 1  

Science Conference Proceedings (OSTI)

A computer code is described which can simulate non-isothermal multi-phase multicomponent flow in porous media. It is applicable to natural-state studies of geothermal systems and groundwater flow. The equations of heat and mass transfer for multiphase flow in porous and permeable media are solved sing the finite element method. The permeability and porosity of the medium are allowed to depend on pressure and temperature. The code also has provisions for movable air and water phases and noncoupled tracers; that is, tracer solutions that do not affect the heat and mass transfer solutions. The tracers can be passive or reactive. The code can simulate two-dimensional, two-dimensional radial, or three-dimensional geometries. A summary of the equations in the model and the numerical solution procedure are provided in this report. A user`s guide and sample problems are also included. The FEHMN (Finite Element Heat and Mass Nuclear) code, described in this report, is a version of FEHM (Finite Element Heat and Mass, Zyvoloski et al., 1988) developed for the Yucca Mountain Site Characterization Project (YMP). The main use of FEHMN will be to assist in the understanding of flow fields in the saturated zone below the potential Yucca Mountain repository.

Zyvoloski, G.; Dash, Z.; Kelkar, S.

1992-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

CHAPARRAL: A library for solving large enclosure radiation heat transfer problems  

SciTech Connect

Large, three-dimensional enclosure radiation beat transfer problems place a heavy demand on computing resources such as computational cycles, memory requirements, disk I/O, and disk space usage. This is primarily due to the computational and memory requirements associated with the view factor calculation and subsequent access of the view factor matrix during solution of the radiosity matrix equation. This is a fundamental problem that constrains Sandia`s current modeling capabilities. Reducing the computational and memory requirements for calculating and manipulating view factors would enable an analyst to increase the level of detail at which a body could be modeled and would have a major impact on many programs at Sandia such as weapon and transportation safety programs, component survivability programs, energy programs, and material processing programs. CHAPARRAL is a library package written to address these problems and is specifically tailored towards the efficient solution of extremely large three-dimensional enclosure radiation heat transfer problems.

Glass, M.W.

1995-08-01T23:59:59.000Z

442

Numerical Investigation of Air-Side Heat Transfer and Pressure Drop in Circular Finned-Tube Heat Exchangers.  

E-Print Network (OSTI)

??A three-dimensional numerical study is performed to investigate the heat transfer and pressure drop performance on the air-side of circular finned tube bundles in cross… (more)

Mon, Mi Sandar

2003-01-01T23:59:59.000Z

443

Experimental and theoretical investigation of heat and mass transfer processes during wood pyrolysis  

Science Conference Proceedings (OSTI)

Thermal decomposition of 25.4 mm diameter dry wood spheres is studied both experimentally and theoretically. Wood spheres were pyrolyzed in a vertical tube furnace at temperatures ranging from 638 K to 879 K. Mass loss and temperatures of the sample were measured during pyrolysis. Center temperature measurements showed two distinct thermal events consisting of sequential endothermic and exothermic reactions. A numerical investigation of these endo/exothermic reactions using various pyrolysis kinetics models was conducted to determine the pyrolysis mechanism and the heats of the pyrolysis reactions. A comparison of the experimental and numerical results showed that (i) Contrary to the suggestions in the literature, the contributions of the secondary tar decomposition and lignin decomposition to the center temperature exothermic peak are small. (ii) Exothermic decomposition of the intermediate solid is responsible for the center temperature peak. (iii) The center temperature plateau is caused by the endothermic decomposition of cellulose. (iv) Internal pressure generation was found to be quite important because it controls the pyrolyzate mass transfer and thus affects both the heat transfer and the residence time of the pyrolysis gases for secondary decomposition. Based on the experimental and numerical results, a new wood pyrolysis model is proposed. The model consists of three endothermic parallel reactions producing tar, gas and intermediate solid and subsequent exothermic decomposition of the intermediate solid to char and exothermic decomposition of tar to char and gas. The proposed pyrolysis model shows good agreement with the experiments. Pressure calculations based on the new pyrolysis model revealed that high pressure is generated inside the biomass particle during pyrolysis and sample splitting was observed during the experiments. The splitting is due to both weakening of the structure and internal pressure generation during pyrolysis. At low heating rates, structural weakness is the primary factor, whereas at high heating rates, internal pressure is the determining factor. It is expected that moisture, while not considered in this work will have a similar effect, but at lower temperatures. (author)

Park, Won Chan; Atreya, Arvind [Department of Mechanical Engineering, University of Michigan, 2158 GGBL 2350 Hayward St., Ann Arbor, MI 48109 (United States); Baum, Howard R. [Department of Fire Protection Engineering, University of Maryland, 3106-D J.M. Patterson Building, College Park, MD 20742 (United States)

2010-03-15T23:59:59.000Z

444

Micro and nanostructured surfaces for enhanced phase change heat transfer  

E-Print Network (OSTI)

Two-phase microchannel heat sinks are of significant interest for thermal management applications, where the latent heat of vaporization offers an efficient method to dissipate large heat fluxes in a compact device. However, ...

Chu, Kuang-Han, Ph. D. Massachusetts Institute of Technology

2013-01-01T23:59:59.000Z

445

HEAT TRANSFER IN POROUS MEDIA WITH FLUID PHASE CHANGES  

E-Print Network (OSTI)

percent compared with heat conduction alone. likely to occurThus, in addition to heat conduction, a large amount ofFourier's law for heat conduction, and the mass balance and

Su, Ho-Jeen.

2010-01-01T23:59:59.000Z

446

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds  

E-Print Network (OSTI)

Adaptive higher order numerical simulation of heat and mass transfer in fluidized beds Ch. Nagaiah1 adaptive numerical results of heat and mass transfer in fluidized beds using higher order time stepping injection. The numerical results are tested with different time stepping methods for different spatial grid

Magdeburg, Universität

447

A Numerical Study on the Enhancement of Heat Transfer by Pressure Distributions in Acoustic Fields  

Science Conference Proceedings (OSTI)

The enhancement of heat transfer in a cavity was investigated in the absence of and in the presence of acoustic streaming induced by ultrasonic waves. The present study provides the experimental and numerical results of heat transfer in the acoustic ... Keywords: Acoustic pressure, Acoustic streaming, Coupled FE-BEM, Particle imaging velocimetry (PIV), Ultrasonic wave

Y. K. Oh; H. D. Yang

2005-01-01T23:59:59.000Z

448

Solving of non-stationary heat transfer in a plane plate  

Science Conference Proceedings (OSTI)

In this paper we present software application destined for study of heat transfer problems that is a part of education of subject Process engineering taught at the Tomas Bata University in Zlin. The application we use as a teaching aid for calculation ... Keywords: maple, non-stationary heat transfer, software application, temperature field

Dagmar Janá?ová; Hana Charvátová; Karel Kolomazník; Vladimír Vašek; Pavel Mokrejš

2011-05-01T23:59:59.000Z

449

Rod Bundle Heat Transfer for Pressurized Water Reactors at Operating Conditions  

Science Conference Proceedings (OSTI)

Currently available heat transfer correlations for subcooled forced convection and subcooled boiling have not been validated with rod-array data at typical PWR fluid conditions. At the present time, rod bundle heat transfer processes cannot be analyzed with sufficient accuracy to make sound decisions regarding changes that might avoid an Axial Offset Anomaly (AOA).

2000-07-14T23:59:59.000Z

450

Application of the TEMPEST computer code to canister-filling heat transfer problems  

SciTech Connect

Pacific Northwest Laboratory (PNL) researchers used the TEMPEST computer code to simulate thermal cooldown behavior of nuclear waste glass after it was poured into steel canisters for long-term storage. The objective of this work was to determine the accuracy and applicability of the TEMPEST code when used to compute canister thermal histories. First, experimental data were obtained to provide the basis for comparing TEMPEST-generated predictions. Five canisters were instrumented with appropriately located radial and axial thermocouples. The canister were filled using the pilot-scale ceramic melter (PSCM) at PNL. Each canister was filled in either a continous or a batch filling mode. One of the canisters was also filled within a turntable simulant (a group of cylindrical shells with heat transfer resistances similar to those in an actual melter turntable). This was necessary to provide a basis for assessing the ability of the TEMPEST code to also model the transient cooling of canisters in a melter turntable. The continous-fill model, Version M, was found to predict temperatures with more accuracy. The turntable simulant experiment demonstrated that TEMPEST can adequately model the asymmetric temperature field caused by the turntable geometry. Further, TEMPEST can acceptably predict the canister cooling history within a turntable, despite code limitations in computing simultaneous radiation and convection heat transfer between shells, along with uncertainty in stainless-steel surface emissivities. Based on the successful performance of TEMPEST Version M, development was initiated to incorporate 1) full viscous glass convection, 2) a dynamically adaptive grid that automatically follows the glass/air interface throughout the transient, and 3) a full enclosure radiation model to allow radiation heat transfer to non-nearest neighbor cells. 5 refs., 47 figs., 17 tabs.

Farnsworth, R.K.; Faletti, D.W.; Budden, M.J.

1988-03-01T23:59:59.000Z

451

Collisionless inter-species energy transfer and turbulent heating in drift wave turbulence  

Science Conference Proceedings (OSTI)

We reconsider the classic problems of calculating 'turbulent heating' and collisionless inter-species transfer of energy in drift wave turbulence. These issues are of interest for low collisionality, electron heated plasmas, such as ITER, where collisionless energy transfer from electrons to ions is likely to be significant. From the wave Poynting theorem at steady state, a volume integral over an annulus r{sub 1}heating as {integral}{sub r{sub 1}} {sup r{sub 2}} dr=-S{sub r}|{sub r{sub 1}{sup r{sub 2}}}{ne}0. Here S{sub r} is the wave energy density flux in the radial direction. Thus, a wave energy flux differential across an annular region indeed gives rise to a net heating, in contrast to previous predictions. This heating is related to the Reynolds work by the zonal flow, since S{sub r} is directly linked to the zonal flow drive. In addition to net heating, there is inter-species heat transfer. For collisionless electron drift waves, the total turbulent energy source for collisionless heat transfer is due to quasilinear electron cooling. Subsequent quasilinear ion heating occurs through linear ion Landau damping. In addition, perpendicular heating via ion polarization currents contributes to ion heating. Since at steady state, Reynolds work of the turbulence on the zonal flow must balance zonal flow frictional damping ({approx}{nu}{sub ii}{sup 2}{approx}|(e{phi}(tilde sign)/T)|{sup 4}), it is no surprise that zonal flow friction appears as an important channel for ion heating. This process of energy transfer via zonal flow has not previously been accounted for in analyses of energy transfer. As an application, we compare the rate of turbulent energy transfer in a low collisionality plasma with the rate of the energy transfer by collisions. The result shows that the collisionless turbulent energy transfer is a significant energy coupling process for ITER plasma.

Zhao, L. [Center for Astrophysics and Space Sciences and Department of Physics, University of California at San Diego, La Jolla, California 92093-0424 (United States); Diamond, P. H. [Center for Astrophysics and Space Sciences and Department of Physics, University of California at San Diego, La Jolla, California 92093-0424 (United States); WCI Center for Fusion Theory, National Fusion Research Institute, Gwahangno113, Yuseong-gu, Daejeon 305-333 (Korea, Republic of)

2012-08-15T23:59:59.000Z

452

Experimental evaluation of a simulation model for wrap-around heat exchanger, solar storage tanks  

DOE Green Energy (OSTI)

The thermal performance of a commercially available 80 gallon, solar storage tank with an integral wrap-around heat exchanger is characterized experimentally an indoor test stand. The experimental results are used to evaluated the accuracy of a previously developed simulation model. Heat input on the collector side of the heat exchanger is held constant causing the heat transfer to reach a quasi-steady state. Temperatures in the heat exchanger and tank increase with time, however, the temperature differences across the heat exchanger remain nearly constant. Several combinations of heat input and collector loop flow are investigated. The development of the tank temperature profiles over time and the overall heat transfer performance predicted by the model are compared with experimental results. The influence of an electric auxiliary heater located in the top of the solar storage tank on the heat exchanger performance is investigated. Experimental normalization of the model is considered and modifications to the model and experiments are recommended.

Miller, J.A.; Hittle, D.C.

1995-05-01T23:59:59.000Z

453

The Economic Mobility in Money Transfer Models  

E-Print Network (OSTI)

In this paper, we investigate the economic mobility in some money transfer models which have been applied into the research on monetary distribution. We demonstrate the mobility by recording the agents' ranks time series and observing the volatility. We also compare the mobility quantitatively by employing an index, "the per capita aggregate change in log-income", raised by economists. Like the shape of distribution, the character of mobility is also decided by the trading rule in these transfer models. It is worth noting that even though different models have the same type of distribution, their mobility characters may be quite different.

Ding, N; Wang, Y; Ding, Ning; Xi, Ning; Wang, Yougui

2005-01-01T23:59:59.000Z

454

Vibration damping and heat transfer using material phase changes  

SciTech Connect

A method and apparatus wherein phase changes in a material can dampen vibrational energy, dampen noise and facilitate heat transfer. One embodiment includes a method for damping vibrational energy in a body. The method comprises attaching a material to the body, wherein the material comprises a substrate, a shape memory alloy layer, and a plurality of temperature change elements. The method further comprises sensing vibrations in the body. In addition, the method comprises indicating to at least a portion of the temperature change elements to provide a temperature change in the shape memory alloy layer, wherein the temperature change is sufficient to provide a phase change in at least a portion of the shape memory alloy layer, and further wherein the phase change consumes a sufficient amount of kinetic energy to dampen at least a portion of the vibrational energy in the body. In other embodiments, the shape memory alloy layer is a thin film. Additional embodiments include a sensor connected to the material.

Kloucek, Petr (Houston, TX); Reynolds, Daniel R. (Oakland, CA)

2009-03-24T23:59:59.000Z

455

Convective heat and mass transfer in compact regenerative dehumidifiers  

Science Conference Proceedings (OSTI)

Regular-density silica gel is identified as the candidate desiccant for regenerative dehumidification of humid air operating at low-regeneration temperatures and high-process humidities. The literature on the equilibrium sorption uptake of water vapor by R. D. silica gel is reviewed in this work, and a large number of experimental sorption data is collected from various technical reports. The Dubinin-Polanyi sorption theory for microporous adsorbents is discussed and applied to the sorptive data. A graphical presentation of the experimental data establishes the characteristic curve for the sorption of water vapor on silica gel. The Dubinin-Astakhov correlation is used to represent the equilibrium sorption isotherm and values for the characteristic sorption energies are determined by curve fitting with the experimental data. An accurate, generalized isotherm equation for the sorption of water vapor on regular density silica gel is presented in the first part of this work. The second part of this work presents an analytical and experimental investigation of the transient heat and mass transfer in laminar flow of humid air over a silica gel surface. Experimental results are presented for the transient response of a parallel-plate dehumidifier matrix in single-blow type experiments.

Van den Buick, E.

1987-01-01T23:59:59.000Z

456

Dual-circuit embossed-sheet heat-transfer panel  

DOE Patents (OSTI)

A heat transfer panel provides redundant cooling for fusion reactors or the like environment requiring low-mass construction. Redundant cooling is provided by two independent cooling circuits, each circuit consisting of a series of channels joined to inlet and outlet headers. The panel comprises a welded joinder of two full-size and two much smaller partial-size sheets. The first full-size sheet is embossed for form first portions of channels for the first and second circuits, as well as a header for the first circuit. The second full-sized sheet is then laid over and welded to the first full-size sheet. The first and second partial-size sheets are then overlaid on separate portions of the second full-sized sheet, and are welded thereto. The first and second partial-sized sheets are embossed to form inlet and outlet headers, which communicate with channels of the second circuit through apertures formed in the second full-sized sheet.

Morgan, G.D.

1982-08-23T23:59:59.000Z

457

Exact microscopic theory of electromagnetic heat transfer between a dielectric sphere and plate  

E-Print Network (OSTI)

Near-field electromagnetic heat transfer holds great potential for the advancement of nanotechnology. Whereas far-field electromagnetic heat transfer is constrained by Planck's blackbody limit, the increased density of states in the near-field enhances heat transfer rates by orders of magnitude relative to the conventional limit. Such enhancement opens new possibilities in numerous applications, including thermal-photo-voltaics, nano-patterning, and imaging. The advancement in this area, however, has been hampered by the lack of rigorous theoretical treatment, especially for geometries that are of direct experimental relevance. Here we introduce an efficient computational strategy, and present the first rigorous calculation of electromagnetic heat transfer in a sphere-plate geometry, the only geometry where transfer rate beyond blackbody limit has been quantitatively probed at room temperature. Our approach results in a definitive picture unifying various approximations previously used to treat this problem, and provides new physical insights for designing experiments aiming to explore enhanced thermal transfer.

Clayton Otey; Shanhui Fan

2011-03-14T23:59:59.000Z

458

Forced convective flow and heat transfer of upward cocurrent air-water slug flow in vertical plain and swirl tubes  

SciTech Connect

This experimental study comparatively examined the two-phase flow structures, pressured drops and heat transfer performances for the cocurrent air-water slug flows in the vertical tubes with and without the spiky twisted tape insert. The two-phase flow structures in the plain and swirl tubes were imaged using the computerized high frame-rate videography with the Taylor bubble velocity measured. Superficial liquid Reynolds number (Re{sub L}) and air-to-water mass flow ratio (AW), which were respectively in the ranges of 4000-10000 and 0.003-0.02 were selected as the controlling parameters to specify the flow condition and derive the heat transfer correlations. Tube-wise averaged void fraction and Taylor bubble velocity were well correlated by the modified drift flux models for both plain and swirl tubes at the slug flow condition. A set of selected data obtained from the plain and swirl tubes was comparatively examined to highlight the impacts of the spiky twisted tape on the air-water interfacial structure and the pressure drop and heat transfer performances. Empirical heat transfer correlations that permitted the evaluation of individual and interdependent Re{sub L} and AW impacts on heat transfer in the developed flow regions of the plain and swirl tubes at the slug flow condition were derived. (author)

Chang, Shyy Woei [Thermal Fluids Laboratory, National Kaohsiung Marine University, No. 142, Haijhuan Road, Nanzih District, Kaohsiung City 81143 (China); Yang, Tsun Lirng [Department of Marine Engineering, National Kaohsiung Marine University, No. 142, Haijhuan Road, Nanzih District, Kaohsiung City 81143 (China)

2009-10-15T23:59:59.000Z

459

Downflow heat transfer in a heated ribbed vertical annulus with a cosine power profile  

Science Conference Proceedings (OSTI)

Experiments designed to investigate downflow heat transfer in a heated, ribbed annulus test section simulating one of the annular coolant channels of a Savannah River Plant production reactor Mark 22 fuel assembly have been conducted at the Idaho National Engineering Laboratory. The inner surface of the annulus was constructed of aluminum and was electrically heated to provide an axial cosine power profile and a flat azimuthal power shape. Data presented in this report are from the ECS-2c series, which was a follow on series to the ECS-2b series, conducted specifically to provide additional data on the effect of different powers at the same test conditions, for use in evaluation of possible power effects on the aluminum temperature measurements. Electrical powers at 90%, 100%, and 110% of the power required to result in the maximum aluminum temperature at fluid saturation temperature were used at each set of test conditions previously used in the ECS-2b series. The ECS-2b series was conducted in the same test rig as the previous ECS-2b series. Data and experimental description for the ECS-2b series is provided in a previous report. 18 refs., 25 figs., 3 tabs.

Anderson, J.L.; Condie, K.G.; Larson, T.K.

1991-10-01T23:59:59.000Z

460

Theoretical Design of Thermosyphon for Process Heat Transfer from NGNP to Hydrogen Plant  

DOE Green Energy (OSTI)

The Next Generation Nuclear Plant (NGNP) will most likely produce electricity and process heat, with both being considered for hydrogen production. To capture nuclear process heat, and transport it to a distant industrial facility requires a high temperature system of heat exchangers, pumps and/or compressors. The heat transfer system is particularly challenging not only due to the elevated temperatures (up to ~ 1300K) and industrial scale power transport (=50 MW), but also due to a potentially large separation distance between the nuclear and industrial plants (100+m) dictated by safety and licensing mandates. The work reported here is the preliminary analysis of two-phase thermosyphon heat transfer performance with alkali metals. A thermosyphon is a device for transporting heat from one point to another with quite extraordinary properties. In contrast to single-phased forced convective heat transfer via ‘pumping a fluid’, a thermosyphon (also called a wickless heat pipe) transfers heat through the vaporization / condensing process. The condensate is further returned to the hot source by gravity, i.e. without any requirement of pumps or compressors. With this mode of heat transfer, the thermosyphon has the capability to transport heat at high rates over appreciable distances, virtually isothermally and without any requirement for external pumping devices. Two-phase heat transfer by a thermosyphon has the advantage of high enthalpy transport that includes the sensible heat of the liquid, the latent heat of vaporization, and vapor superheat. In contrast, single-phase forced convection transports only the sensible heat of the fluid. Additionally, vapor-phase velocities within a thermosyphon are much greater than single-phase liquid velocities within a forced convective loop. Thermosyphon performance can be limited by the sonic limit (choking) or vapor flow and/or by condensate entrainment. Proper thermosyphon requires analysis of both.

Piyush Sabharwall; Mike Patterson; Fred Gunnerson

2008-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "heat transfer model" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


461

A numerical study of free convective heat transfer in a double-glazed window with a between-pane Venetian blind.  

E-Print Network (OSTI)

??The free convective heat transfer in a double-glazed window with a between-pane Venetian blind has been studied numerically. The model geometry consists of a two-dimensional… (more)

Avedissian, Tony

2006-01-01T23:59:59.000Z

462

PARAMETER ESTIMATION BASED MODELS OF WATER SOURCE HEAT PUMPS  

E-Print Network (OSTI)

a two-year research program in heat transfer and viscoelastic fluid flows, after working for some time Sciences), Fluid Mechanics, Heat Transfer and related (815) 753-9975 Page 1 of 2WSEAS Conferences: www on HEAT and MASS TRANSFER (HMT'09) [Download a Map of the area (16 Kbytes)] [Download a Map of the city

463

Experimental study of natural convective heat transfer in a vertical hexagonal sub channel  

Science Conference Proceedings (OSTI)

The development of new practices in nuclear reactor safety aspects and optimization of recent nuclear reactors, including the APWR and the PHWR reactors, needs a knowledge on natural convective heat transfer within sub-channels formed among several nuclear fuel rods or heat exchanger tubes. Unfortunately, the currently available empirical correlation equations for such heat transfer modes are limited and researches on convective heat transfer within a bundle of vertical cylinders (especially within the natural convection modes) are scarcely done. Although boundary layers around the heat exchanger cylinders or fuel rods may be dominated by their entry regions, most of available convection correlation equations are for fully developed boundary layers. Recently, an experimental study on natural convective heat transfer in a subchannel formed by several heated parallel cylinders that arranged in a hexagonal configuration has been being done. The study seeks for a new convection correlation for the natural convective heat transfer in the sub-channel formed among the hexagonal vertical cylinders. A new convective heat transfer correlation equation has been obtained from the study and compared to several similar equations in literatures.

Tandian, Nathanael P.; Umar, Efrizon; Hardianto, Toto; Febriyanto, Catur [Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132 (Indonesia); Nuclear Technology Center for Materials and Radiometry, National Nuclear Energy Agency, Bandung (Indonesia); Faculty of Mechanical and Aerospace Engineering, Institut Teknologi Bandung, Jl. Ganesa 10, Bandung 40132 (Indonesia); Nuclear Energy Regulation Agency, Jakarta (Indonesia)

2012-06-06T23:59:59.000Z

464

Numerical simulation of fluid flow and heat transfer in a water heater  

Science Conference Proceedings (OSTI)

Energy consumption represents a major concern, considering the limited resources and latest targets for lower emissions of carbon dioxide. Therefore design of electric heating elements for household and industry are more and more subject to optimization, ... Keywords: electric heating, finite elements, fluid flow, heat transfer

Mircea Nicoar?; Aurel R?du??; Lauren?iu Roland Cucuruz; Cosmin Locovei

2010-04-01T23:59:59.000Z

465

International Communications in Heat and Mass Transfer, volume 39, issue 10, December 2012, Pages 15191521.  

E-Print Network (OSTI)

.P. Hodson, T.J. Lu, Fluid-flow and endwall heat-transfer characteristics of an ultralight lattice and water as the working fluid. Thermodynamic design principles for a multifunctional heat pipe sandwich.P. Hodson, D.T. Queheillalt, D.J. Sypeck, H.N.G. Wadley, The effects of topology upon fluid-flow and heat

Cambridge, University of

466

Apparatus and method for controlling heat transfer between a fluidized bed and tubes immersed therein  

DOE Patents (OSTI)

In a fluidized bed of solid particles having one or more heat exchange tubes immersed therein, the rate of heat transfer between the fluidized particles and a fluid flowing through the immersed heat exchange tubes is controlled by rotating an arcuate shield apparatus about each tube to selectively expose various portions of the tube to the fluidized particles.

Hodges, James L. (3 Hilltop Ave., Vernon, CT 06066); Cerkanowicz, Anthony E. (8 Fieldstone Dr., Livingston, NJ 07039)

1983-01-01T23:59:59.000Z

467

Apparatus and method for controlling heat transfer between a fluidized bed and tubes immersed therein  

DOE Patents (OSTI)

In a fluidized bed of solid particles having one or more heat exchange tubes immersed therein, the rate of heat transfer between the fluidized particles and a fluid flowing through the immersed heat exchange tubes is controlled by rotating an arcuate shield apparatus about each tube to selectively expose various portions of the tube to the fluidized particles.

Hodges, James L. (3 Hilltop Ave., Vernon, CT 06066); Cerkanowicz, Anthony E. (8 Fieldstone Dr., Livingston, NJ 07039)

1982-01-01T23:59:59.000Z

468

Generator-Absorber heat exchange transfer apparatus and method using an intermediate liquor  

DOE Patents (OSTI)

Numerous embodiments and related methods for generator-absorber heat exchange (GAX) are disclosed, particularly for absorption heat pump systems. Such embodiments and related methods use the working solution of the absorption system for the heat transfer medium where the working solution has an intermediate liquor concentration.

Phillips, Benjamin A. (Benton Harbor, MI); Zawacki, Thomas S. (St. Joseph, MI)

1996-11-05T23:59:59.000Z

469

Effects of particle concentration and surfactant use in convective heat transfer of CuO nanofluids in microchannel flow.  

E-Print Network (OSTI)

??Heat exchange systems used in everything from cars to microelectronics have rapidly advanced in recent years to offer high heat transfer rates in increasingly smaller… (more)

Byrne, Matthew Davidson