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Note: This page contains sample records for the topic "high heat flow" 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.


1

MERLOT: a model for flow and heat transfer through porous media for high heat flux applications  

E-Print Network [OSTI]

MERLOT: a model for flow and heat transfer through porous media for high heat flux applications A Abstract Fusion power plant studies have found helium to be an attractive coolant based on its safety tend to provide modest heat transfer performance due to their inherently low heat capacity and heat

Raffray, A. René

2

Flow and heat transfer in porous micro heat sink for thermal management of high power LEDs  

Science Journals Connector (OSTI)

A novel porous micro heat sink system is presented for thermal management of high power LEDs, which has high heat transport capability. The operational principle and heat transfer characteristics of porous micro heat sink are analyzed. Numerical model ... Keywords: Heat dissipation, High heat flux, High power LEDs, Porous media, Porous micro heat sink

Z. M. Wan; J. Liu; K. L. Su; X. H. Hu; S. S. M

2011-05-01T23:59:59.000Z

3

EXPERIMENTAL INVESTIGATION OF TURBULENT HEAT TRANSFER OF HIGH PRANDTL NUMBER FLUID FLOW UNDER STRONG MAGNETIC FIELD  

E-Print Network [OSTI]

EXPERIMENTAL INVESTIGATION OF TURBULENT HEAT TRANSFER OF HIGH PRANDTL NUMBER FLUID FLOW UNDER to the heat transfer characteristic: Flibe is a high Prandtl number fluid. For high Prandtl number fluid, there is a severe limitation of temperature window due to its high melting point. The turbulent heat transfer is

Abdou, Mohamed

4

Utility of Bromide and Heat Tracers for Aquifer Characterization Affected by Highly Transient Flow Conditions  

SciTech Connect (OSTI)

A tracer test using both bromide and heat tracers conducted at the Integrated Field Research Challenge site in Hanford 300 Area (300A), Washington, provided an instrument for evaluating the utility of bromide and heat tracers for aquifer characterization. The bromide tracer data were critical to improving the calibration of the flow model complicated by the highly dynamic nature of the flow field. However, most bromide concentrations were obtained from fully screened observation wells, lacking depth-specific resolution for vertical characterization. On the other hand, depth-specific temperature data were relatively simple and inexpensive to acquire. However, temperature-driven fluid density effects influenced heat plume movement. Moreover, the temperature data contained “noise” caused by heating during fluid injection and sampling events. Using the hydraulic conductivity distribution obtained from the calibration of the bromide transport model, the temperature depth profiles and arrival times of temperature peaks simulated by the heat transport model were in reasonable agreement with observations. This suggested that heat can be used as a cost-effective proxy for solute tracers for calibration of the hydraulic conductivity distribution, especially in the vertical direction. However, a heat tracer test must be carefully designed and executed to minimize fluid density effects and sources of noise in temperature data. A sensitivity analysis also revealed that heat transport was most sensitive to hydraulic conductivity and porosity, less sensitive to thermal distribution factor, and least sensitive to thermal dispersion and heat conduction. This indicated that the hydraulic conductivity remains the primary calibration parameter for heat transport.

Ma, Rui; Zheng, Chunmiao; Zachara, John M.; Tonkin, Matthew J.

2012-08-29T23:59:59.000Z

5

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

6

Potassium, Uranium, Thorium Radiogenic Heat Contribution To Heat Flow In  

Open Energy Info (EERE)

Potassium, Uranium, Thorium Radiogenic Heat Contribution To Heat Flow In Potassium, Uranium, Thorium Radiogenic Heat Contribution To Heat Flow In The Precambrian And Younger Silicic Rocks Of The Zuni And Florida Mountains, New Mexico (Usa) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Potassium, Uranium, Thorium Radiogenic Heat Contribution To Heat Flow In The Precambrian And Younger Silicic Rocks Of The Zuni And Florida Mountains, New Mexico (Usa) Details Activities (4) Areas (2) Regions (0) Abstract: High heat flow in the Zuni Mountains, New Mexico, U.S.A., has been explained by the possible presence of a buried felsic pluton. Alternately, high K, U, Th abundances have been proposed to account for part of the high heat flow. The mean radiogenic heat contribution for 60 samples of Precambrian core rocks is 7.23 μcal/gm-yr, which is slightly

7

Convective heat flow probe  

DOE Patents [OSTI]

A convective heat flow probe device is provided which measures heat flow and fluid flow magnitude in the formation surrounding a borehole. The probe comprises an elongate housing adapted to be lowered down into the borehole; a plurality of heaters extending along the probe for heating the formation surrounding the borehole; a plurality of temperature sensors arranged around the periphery of the probe for measuring the temperature of the surrounding formation after heating thereof by the heater elements. The temperature sensors and heater elements are mounted in a plurality of separate heater pads which are supported by the housing and which are adapted to be radially expanded into firm engagement with the walls of the borehole. The heat supplied by the heater elements and the temperatures measured by the temperature sensors are monitored and used in providing the desired measurements. The outer peripheral surfaces of the heater pads are configured as segments of a cylinder and form a full cylinder when taken together. A plurality of temperature sensors are located on each pad so as to extend along the length and across the width thereof, with a heating element being located in each pad beneath the temperature sensors. An expansion mechanism driven by a clamping motor provides expansion and retraction of the heater pads and expandable packet-type seals are provided along the probe above and below the heater pads.

Dunn, J.C.; Hardee, H.C.; Striker, R.P.

1984-01-09T23:59:59.000Z

8

Planetary heat flow measurements  

Science Journals Connector (OSTI)

...ESA's Rosetta mission towards comet Churyumov-Gerasimenko. It...Heat flow measurements on comets have a different motivation...penetrator is by no means limited to comets; it has also been tested in...measurement. Currently, a landing on Mercury within the framework...

2005-01-01T23:59:59.000Z

9

Experimental study of heat flows in the walls of a high-enthalpy mhd channel  

SciTech Connect (OSTI)

This article reports results of experimental studies of local heat flows in the walls of an MHD channel during different regimes of its operation. Special attention was given to aspects of the reliability of measurement of heat flow to B-walls. Tests were conducted on a unit consisting of a Faraday MHD channel with sectional electrodes operating in the accelerator regime. A basic diagram of the unit is shown. Tests were conducted with the primary nozzle and power was supplied along zones 160 and 280 mm long. The data obtained were analyzed using the electrogasdynamic flow pattern established for each regime from numerical solution of a system of quasiunidimensional magnetogasdynamic equations. Results are presented of measurement and analysis of gasdynamic and electrodynamic characteristics of flow in the MHD channel.

Alferov, V.I.; Rudakova, A.P.; Shcherbakov, G.I.; Sukhobokov, A.D.; Vitskoskaya, O.N.

1986-01-01T23:59:59.000Z

10

Heat flow on the southern Colorado Plateau  

Science Journals Connector (OSTI)

Heat-flow data from the study area in the southern Colorado Plateau indicate a pattern of local anomalies having relatively high heat flow superimposed on a regional, intermediate heat-flow setting. While many of the conventional heat-flow data are relatively shallow and may be perturbed by groundwater circulation, bottom-hole temperature data from two relatively deep petroleum exploration drill holes near the southern plateau periphery yield intermediate heat-flow estimates. The mean heat flow within the volcanically active Jemez zone does not appear to be significantly greater than the mean heat flow for the remainder of the study area. This is due to the presence of high heat-flow values outside the Jemez zone. Sites with relatively high heat flow located towards the plateau interior and away from recent volcanic activity of the Jemez zone may reflect magma intrusion and/or groundwater movement along crustal zones of weakness associated with Laramide deformation (monoclines). The heat-flow data are consistent with coal maturation data, which suggest that any regional post-Cretaceous thermal events that may be associated with the southern Plateau boundary have been initiated relatively recently, or are occurring at relatively great depths, or are occurring south of the Jemez lineament.

Jeffrie Minier; Marshall Reiter

1991-01-01T23:59:59.000Z

11

Double layer created by electron cyclotron resonance heating in an inhomogeneously magnetized plasma with high-speed ion flow  

SciTech Connect (OSTI)

A potential jump, i.e., an electric double layer (DL) is formed near an electron cyclotron resonance (ECR) point when an electron cyclotron wave is injected into an inhomogeneously magnetized plasma with high-speed ion flow. A charge separation is caused by an electron reflection due to -{mu}{nabla}B{sub z} force enhanced by ECR heating and ion inertia. It is clearly demonstrated in the experiment that the potential height of the DL is almost proportional to the field-aligned ion flow energy; the DL is found to be self-consistently formed for maintaining charge neutrality by reflecting a part of the flowing ions.

Takahashi, K.; Kaneko, T.; Hatakeyama, R. [Department of Electronic Engineering, Tohoku University, Sendai, 980-8579 (Japan)

2008-07-15T23:59:59.000Z

12

Geographical Coincidence of High Heat Flow, High Seismicity, and Upwelling, with Hydrocarbon Deposits, Phosphorites, Evaporites, and Uranium Ores  

Science Journals Connector (OSTI)

...sea and seismicity and geothermal heat flux. We suggest...upwelling caused by the geothermal heat (2), which brings...sedimentary rocks. High geothermal heat fluxes correlate...Lawrence River, as well as a fourth line along...Arizona, Montana, New Mexico, and Utah. Lignites...

L. M. Libby; W. F. Libby

1974-01-01T23:59:59.000Z

13

Countercurrent flow limited (CCFL) heat flux in the high flux isotope reactor (HFIR) fuel element  

SciTech Connect (OSTI)

The countercurrent flow (CCF) performance in the fuel element region of the HFIR is examined experimentally and theoretically. The fuel element consists of two concentric annuli filled with aluminum clad fuel plates of 1.27 mm thickness separated by 1.27 mm flow channels. The plates are curved as they go radially outward to accomplish constant flow channel width and constant metal-to-coolant ratio. A full-scale HFIR fuel element mock-up is studied in an adiabatic air-water CCF experiment. A review of CCF models for narrow channels is presented along with the treatment of CCFs in system of parallel channels. The experimental results are related to the existing models and a mechanistic model for the annular'' CCF in a narrow channel is developed that captures the data trends well. The results of the experiment are used to calculate the CCFL heat flux of the HFIR fuel assembly. It was determined that the HFIR fuel assembly can reject 0.62 Mw of thermal power in the CCFL situation. 31 refs., 17 figs.

Ruggles, A.E.

1990-10-12T23:59:59.000Z

14

Earth's Crust: Heat Flow Relationships  

Science Journals Connector (OSTI)

... of heat flow through the Earth's surface at any point requires two measurements, the geothermal gradient itself and the thermal conductivity of the adjacent rocks. In the oceanic crust, ... variations in heat flow from point to point are governed essentially by variations in the geothermal gradient. In continents, however, the story is different. Correlation and regression analyses carried ...

Our Geomagnetism Correspondent

1970-07-11T23:59:59.000Z

15

Hydrodynamics, heat transfer and flow boiling instabilities in microchannels   

E-Print Network [OSTI]

Boiling in microchannels is a very efficient mode of heat transfer with high heat and mass transfer coefficients achieved. Less pumping power is required for two-phase flows than for single-phase liquid flows to achieve ...

Barber, Jacqueline Claire

2010-01-01T23:59:59.000Z

16

Plume heat flow is much lower than CMB heat flow Eric Mittelstaedt a,*, Paul J. Tackley a,b  

E-Print Network [OSTI]

to follow a power-law size distribution, estimated a plume heat flux as high as 35% of surface heat fluxPlume heat flow is much lower than CMB heat flow Eric Mittelstaedt a,*, Paul J. Tackley a, of the heat conducted across the CMB. Here this assumption is explored using numerical convection models

Tackley, Paul J.

17

Colorado: Isothermal Battery Calorimeter Quantifies Heat Flow...  

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

Isothermal Battery Calorimeter Quantifies Heat Flow, Helps Make Safer, Longer-lasting Batteries Colorado: Isothermal Battery Calorimeter Quantifies Heat Flow, Helps Make Safer,...

18

Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method  

Science Journals Connector (OSTI)

The present paper deals with the two-dimensional numerical simulation of gaseous flow and heat transfer in planar microchannel and nanochannel with different wall temperatures in transitional regime 0.1?Kn?1. An atomistic molecular simulation method is used known as thermal lattice-Boltzmann method. The results of simulation are presented in four cases corresponding to the Fourier flow, shear-driven flow (Couette flow), pressure-driven flow (Poiseuille flow), and mixed shear–pressure-driven flow in the developing and fully developed regions. The mixed shear–pressure-driven flow is divided into two subcases with shear stress and pressure gradient acting in the same and the opposite directions. Normalized temperature and velocity profiles across the channel, distribution of local wall Nusselt number, and friction coefficient are illustrated. Using this method, nonlinear pressure distribution in the streamwise direction, reduction in mass flow rate, Cf?Re, and Nu by increasing the Knudsen number are studied. It is seen that for Couette flow, Nu over the hotter plate is greater than the cooler plate, but for the pressure-driven flow with stationary wall temperature dependency of viscosity and thermal conductivity causes this trend to be reversed. The reversed flow appearance in the velocity profile is captured in the case of opposite shear–pressure-driven flow.

J. Ghazanfarian and A. Abbassi

2010-08-13T23:59:59.000Z

19

A Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow...  

Open Energy Info (EERE)

Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow Measurements And Heat-Flow Estimates From The Uk Geothermal Catalogue Jump to: navigation, search OpenEI Reference...

20

A Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow Measurements  

Open Energy Info (EERE)

Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow Measurements Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow Measurements And Heat-Flow Estimates From The Uk Geothermal Catalogue Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Simple Heat-Flow Quality Function And Appraisal Of Heat-Flow Measurements And Heat-Flow Estimates From The Uk Geothermal Catalogue Details Activities (0) Areas (0) Regions (0) Abstract: A comprehensive database of temperature, heat flow, thermal conductivity and geochemistry is the basis of geothermal modelling. The latest revision (1987) of the UK Geothermal Catalogue (UKGC) contains over 2600 temperatures at over 1150 sites and over 200 observations of heat flow. About 93% of the temperature data are from depths less than 2000 m and about 50% are Bottom Hole Temperatures (BHT). Heat-flow density

Note: This page contains sample records for the topic "high heat flow" 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

OPTIMIZATION AND DESIGN GUIDELINES FOR HIGH FLUX MICRO-CHANNEL HEAT SINKS FOR LIQUID AND GASEOUS SINGLE-PHASE FLOW  

E-Print Network [OSTI]

orders of magnitude, especially for high heat flux devices. Using water and air as coolants, designs with the optimization tool are generalized and optimum configurations are illustrated on design charts. Physical trends

Müller, Norbert

22

Geothermal Heat Flow and Existing Geothermal Plants | Department...  

Energy Savers [EERE]

Geothermal Heat Flow and Existing Geothermal Plants Geothermal Heat Flow and Existing Geothermal Plants Geothermal Heat Flow and Existing Plants With plants in development. Click...

23

Effects of turbulence model on convective heat transfer of coolant flow in a prismatic very high temperature reactor core  

SciTech Connect (OSTI)

The existing study of Spall et al. shows that only {nu}{sup 2}-f turbulence model well matches with the experimental data of Shehata and McEligot which were obtained under strongly heated gas flows. Significant over-predictions in those literatures were observed in the convective heat transfer with the other famous turbulence models such as the k-{epsilon} and k-{omega} models. In spite of such good evidence about the performance of the{nu}{sup 2}-f model, the application of the {nu}{sup 2}-f model to the thermo-fluid analysis of a prismatic core is very rare. In this paper, therefore, the convective heat transfer of the coolant flow in a prismatic core has been investigated using the {nu}{sup 2}-f model. Computational fluid dynamics (CFD) calculations have been carried out for the typical unit cell geometry of a prismatic fuel column with typical operating conditions of prismatic designs. The tested Reynolds numbers of the coolant flow are 10,000, 20,000, 30,000 and 50,000. The predicted Nusselt numbers with the {nu}{sup 2}-f model are compared with the results by the other turbulence models (k-{epsilon} and SST) as well as the empirical correlations. (authors)

Lee, S. N.; Tak, N. I.; Kim, M. H.; Noh, J. M. [Korea Atomic Energy Research Inst., Daedeok-daero 989-11, Yuseong-gu, Daejeon (Korea, Republic of)

2012-07-01T23:59:59.000Z

24

Reply to “Comment on ‘Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method”’  

Science Journals Connector (OSTI)

In this reply to the Comment by Li-Shi Luo, we discuss the results of the lattice Bhatnagar-Gross-Krook (LBGK) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn?1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that, with the use of the LBGK model in the thermal lattice Boltzmann method for Kn?0.8, some approximations appear in the negative pressure deviation from the linear distribution along the channel. But for Kn<0.8, the velocity and temperature profiles, compressibility effects, Knudsen layer capturing, and Knudsen paradox phenomenon can be predicted by the LBGK model. We also reject Li-Shi Luo’s claim about the nonconvergence of our numerical scheme by presenting a velocity profile across the channel corresponding to three different high-resolution meshes.

J. Ghazanfarian and A. Abbassi

2011-10-25T23:59:59.000Z

25

Cryogenic Fluid Flow Heat Transfer in a Porous Heat Exchanger  

Science Journals Connector (OSTI)

The recent utilization of porous heat exchangers in various key industries has aroused considerable interest in the heat transfer and fluid dynamics processes in channel flows involving suction...1], suction with...

L. L. Vasiliev; G. I. Bobrova; S. K. Vinokurov…

1978-01-01T23:59:59.000Z

26

Radio frequency (RF) heated supersonic flow laboratory  

SciTech Connect (OSTI)

A unique supersonic flow apparatus which employs an inductively-coupled, radio frequency (RF) torch to supply high enthalpy source gas to the nozzle inlet is described. The main features of this system are the plasma tube, a cooled nozzle assembly, and a combustion/expansion chamber with a heat exchanger. A description of these components with current test data is presented. In addition, a discussion of anticipated experiments utilizing this system is included.

Wantuck, P.; Watanabe, H.

1990-01-01T23:59:59.000Z

27

Heat Pump for High School Heat Recovery  

E-Print Network [OSTI]

ICEBO2006, Shenzhen, China Renewable Energy Resources and a Greener Future Vol.VIII-12-1 Heat Pump for High School Bathroom Heat Recovery Kunrong Huang Hanqing Wang Xiangjiang Zhou Associate professor Professor Professor School...

Huang, K.; Wang, H.; Zhou, X.

2006-01-01T23:59:59.000Z

28

Turbine vanes experience high convective surface heat transfer as a consequence of the turbulent flow exiting the combustor. Before im-  

E-Print Network [OSTI]

1 Abstract Turbine vanes experience high convective surface heat transfer as a consequence region of the passage reacts as it passes between two adjacent turbine vanes. In this study, a scaled-up turbine vane geometry was used in a low-speed wind tunnel simulation. The test section included a cen

Thole, Karen A.

29

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...

Singh, K. P.

1979-01-01T23:59:59.000Z

30

Modeling of strongly heat-driven flow processes at a potential high-level nuclear waste repository at Yucca Mountain, Nevada  

SciTech Connect (OSTI)

Two complementary numerical models for analyzing high-level nuclear waste emplacement at Yucca Mountain have been developed. A vertical cross-sectional (X-Z) model permits a realistic representation of hydrogeologic features, such as alternating tilting layers of welded and non-welded tuffs. fault zones, and surface topography. An alternative radially symmetric (R-Z) model is more limited in its ability to describe the hydrogeology of the site, but is better suited to model heat transfer in the host rock. Our models include a comprehensive description of multiphase fluid and heat flow processes, including strong enhancements of vapor diffusion from pore-level phase change effects. The neighborhood of the repository is found to partially dry out from the waste heat. A condensation halo of large liquid saturation forms around the drying zone, from which liquid flows downward at large rates. System response to infiltration from the surface and to ventilation of mined openings is evaluated. The impact of the various flow processes on the waste isolation capabilities of the site is discussed.

Pruess, K.; Tsang, Y.

1993-01-01T23:59:59.000Z

31

An evaluation of heat flow transducers as a means of determining soil heat flow  

E-Print Network [OSTI]

provided to the Micrometeorology Section, Department of Oceanography and Meteorology, ARM College of Texas by the Signal Corps of the United States Army, under Contract No. DA 36-039 AMC-02195 (E). The heat flow plates used in this study were provided... surface soil heat flow. The results show that acceptable performance of the plates in the measurement of heat flow is possible although in general should not be expected without thorough testing, and even then there are restrictive considerations...

King, Barney L. D

2012-06-07T23:59:59.000Z

32

Measurements of Heats of Adsorption of Organic Vapours on Adsorbents of High Surface Area using a Continuous Flow Calorimeter  

Science Journals Connector (OSTI)

... gel. It has been reported3 that heats of adsorption of this magnitude are obtained on adsorbents of this type when the surface coverage is low. This probably explains the very ...

G. H. BELL; A. J. GROSZEK

1961-09-16T23:59:59.000Z

33

Heat flow in the postquasistatic approximation  

SciTech Connect (OSTI)

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model that corresponds to an incompressible fluid departing from the static equilibrium, it is not possible to go far from the initial state after the emission of a small amount of energy. Initially collapsing distributions of matter are not permitted. Emission of energy can be considered as a mechanism to avoid the collapse. If the distribution collapses initially and emits one hundredth of the initial mass only the outermost layers evolve. For a model that corresponds to a highly compressed Fermi gas, only the outermost shell can evolve with a shorter hydrodynamic time scale.

Rodriguez-Mueller, B. [Computational Science Research Center, College of Sciences, San Diego State University, San Diego, California (United States); Peralta, C. [Deutscher Wetterdienst, Frankfurter Strasse 135, 63067 Offenbach (Germany); School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Barreto, W. [Centro de Fisica Fundamental, Facultad de Ciencias, Universidad de Los Andes, Merida (Venezuela, Bolivarian Republic of); Rosales, L. [Laboratorio de Fisica Computacional, Universidad Experimental Politecnica, 'Antonio Jose de Sucre', Puerto Ordaz (Venezuela, Bolivarian Republic of)

2010-08-15T23:59:59.000Z

34

Heat flow in the postquasistatic approximation  

E-Print Network [OSTI]

We apply the postquasistatic approximation to study the evolution of spherically symmetric fluid distributions undergoing dissipation in the form of radial heat flow. For a model which corresponds to an incompressible fluid departing from the static equilibrium, it is not possible to go far from the initial state after the emission of a small amount of energy. Initially collapsing distributions of matter are not permitted. Emission of energy can be considered as a mechanism to avoid the collapse. If the distribution collapses initially and emits one hundredth of the initial mass only the outermost layers evolve. For a model which corresponds to a highly compressed Fermi gas, only the outermost shell can evolve with a shorter hydrodynamic time scale.

B. Rodríguez-Mueller; C. Peralta; W. Barreto; L. Rosales

2010-05-10T23:59:59.000Z

35

Heat Transfer in Smooth and Ribbed Rectangular Two-Pass Channels with a Developing Flow Entrance at High Rotation Numbers  

E-Print Network [OSTI]

Cooling channels with a developing flow entrance condition and aspect ratios of 1:4 and 2:1 were studied. The range of the rotation number and buoyancy parameter for the selected AR channels was extended. The maximum Ro and Bo for the 1:4 channel...

Huh, Michael

2010-01-16T23:59:59.000Z

36

Cryogenic heat exchanger with turbulent flows  

Science Journals Connector (OSTI)

An evaporator-type cryogenic heat exchanger is designed and built for introducing fluid–solid heat exchange phenomena to undergraduates in a practical and efficient way. The heat exchanger functions at liquid nitrogen temperature and enables cooling of N2 and He gases from room temperatures. We present first the experimental results of various parameters which characterize the heat exchanger (efficiency, number of transfer units, heat exchange coefficient, etc) as a function of the mass flow rate of the gas to be cooled. An analysis of the Nu–Re diagram is also presented. All experiments were conducted with N2 gas. The scope of this tool is readily extended to research purposes.

Jay Amrit; Christelle Douay; Francis Dubois; Gérard Defresne

2012-01-01T23:59:59.000Z

37

Hot springs, geochemistry, and regional heat flow of northcentral Mexico  

SciTech Connect (OSTI)

To date we have found, sampled and performed chemical analyses on 21 hot springs (T > 30/sup 0/C), 4 hot wells (T > 30/sup 0/C) and 15 warm springs (T = 25 to 30/sup 0/C) from the states of Chihuahua, Coahuila and Sonora, Mexico. Also in order to establish background chemistry, an additional 250 cold wells and springs (T = 12 to 25/sup 0/C) were sampled and analyzed and several hundred water analyses from the several thousand provided by various Mexican agencies were included. The technique of silica geothermometry was used to estimate the regional heat flow of northcentral Mexico. Both the traditional heat flow and the silica heat flow values are generally high and show considerable scatter as is typical of areas having Tertiary and Quaternary volcanic and tectonic activity. Specific areas of high heat flow (> 2.5 HFU) include the Presidio and Los Muertos Bolsons, the Cuidad Chihuahua-Chuatemoc area, the Delicias area, and the area south of the San Bernardino Bolson of southeast Arizona. Areas of lower heat flow (2.0 to 2.5 HFU) include the Jimenez-Camargo region and the area between the Los Muertos and Presidio Bolsons.

Swanberg, C.A.; Marvin, P.R.; Salazar S., L.; Gutierrez, C.G.

1981-10-01T23:59:59.000Z

38

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

39

Triaxial thermopile array geo-heat-flow sensor  

DOE Patents [OSTI]

A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings. 6 figs.

Carrigan, C.R.; Hardee, H.C.; Reynolds, G.D.; Steinfort, T.D.

1990-01-01T23:59:59.000Z

40

Triaxial thermopile array geo-heat-flow sensor  

DOE Patents [OSTI]

A triaxial thermopile array geothermal heat flow sensor is designed to measure heat flow in three dimensions in a reconstituted or unperturbed subsurface regime. Heat flow can be measured in conductive or permeable convective media. The sensor may be encased in protective pvc tubing and includes a plurality of thermistors and an array of heat flow transducers arranged in a vertical string. The transducers produce voltage proportional to heat flux along the subsurface regime and permit direct measurement of heat flow in the subsurface regime. The presence of the thermistor array permits a comparison to be made between the heat flow estimates obtained from the transducers and heat flow calculated using temperature differences and Fourier's Law. The device is extremely sensitive with an accuracy of less than 0.1 Heat Flow Units (HFU) and may be used for long term readings.

Carrigan, Charles R. (Tracy, CA); Hardee, Harry C. (Albuquerque, NM); Reynolds, Gerald D. (Tijeras, NM); Steinfort, Terry D. (Tijeras, NM)

1992-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Interpretive geothermal heat flow map of Colorado | Open Energy...  

Open Energy Info (EERE)

Interpretive geothermal heat flow map of Colorado Jump to: navigation, search OpenEI Reference LibraryAdd to library Map: Interpretive geothermal heat flow map of ColoradoInfo...

42

Heat Flow in the Hungarian Basin  

Science Journals Connector (OSTI)

... the basin is deep and the gradient is between 40 and 45 C/km. This geothermal low may be characterized by 1-4-1-6 [jical/cm2 sec except if ... is about 1*5 sec can bo considered as the Western boundary of the Hungarian geothermal anomaly, since heat flow diminishes from that line in the north-west direction to ...

T. BOLDIZSÁR

1964-06-27T23:59:59.000Z

43

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 geometry the flow field influence on the local heat transfer distribution on an evenly cooled scraped heat loss heat loss to the surroundings stst stainless steel plate lc thermo-chromic liquid crystal

Boyer, Edmond

44

PHYSICAL REVIEW E 84, 048302 (2011) Reply to "Comment on `Heat transfer and fluid flow in microchannels and nanochannels  

E-Print Network [OSTI]

PHYSICAL REVIEW E 84, 048302 (2011) Reply to "Comment on `Heat transfer and fluid flow) model for high-Knudsen-number (Kn) flow and heat transfer, in the range of Kn 1. We present various studies employing the LBGK model for high-Kn flow and heat transfer simulations. It is concluded that

Luo, Li-Shi

45

FLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS  

E-Print Network [OSTI]

= heat, f = LO-mode, g = LO, h = LA-mode, i = negligible, j = remote heat sink 7/ 70 #12;Heat conductionFLUID MECHANICS AND HEAT TRANSFER OF ELECTRON FLOW IN SEMICONDUCTORS Mihir Sen Department · Shallow water analogy · Vorticity dynamics · Linear stability analysis · Numerical simulations of heat

Sen, Mihir

46

Thaw flow control for liquid heat transport systems  

DOE Patents [OSTI]

In a liquid metal heat transport system including a source of thaw heat for use in a space reactor power system, the thaw flow throttle or control comprises a fluid passage having forward and reverse flow sections and a partition having a plurality of bleed holes therein to enable fluid flow between the forward and reverse sections. The flow throttle is positioned in the system relatively far from the source of thaw heat.

Kirpich, Aaron S. (Broomall, PA)

1989-01-01T23:59:59.000Z

47

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel  

E-Print Network [OSTI]

Hydrodynamics and heat transfer during flow boiling instabilities in a single microchannel July 2008 Keywords: Boiling Microchannels Visualisation Flow boiling instabilities Heat transfer a b intensification heat removal. Flow boiling heat transfer in microchannel geometry and the associated flow

Aussillous, Pascale

48

Development of a fuel-rod simulator and small-diameter thermocouples for high-temperature, high-heat-flux tests in the Gas-Cooled Fast Reactor Core Flow Test Loop  

SciTech Connect (OSTI)

The Core Flow Test Loop was constructed to perform many of the safety, core design, and mechanical interaction tests in support of the Gas-Cooled Fast Reactor (GCFR) using electrically heated fuel rod simulators (FRSs). Operation includes many off-normal or postulated accident sequences including transient, high-power, and high-temperature operation. The FRS was developed to survive: (1) hundreds of hours of operation at 200 W/cm/sup 2/, 1000/sup 0/C cladding temperature, and (2) 40 h at 40 W/cm/sup 2/, 1200/sup 0/C cladding temperature. Six 0.5-mm type K sheathed thermocouples were placed inside the FRS cladding to measure steady-state and transient temperatures through clad melting at 1370/sup 0/C.

McCulloch, R.W.; MacPherson, R.E.

1983-03-01T23:59:59.000Z

49

Comment on “Heat transfer and fluid flow in microchannels and nanochannels at high Knudsen number using thermal lattice-Boltzmann method”  

Science Journals Connector (OSTI)

In this Comment we reveal the falsehood of the claim that the lattice Bhatnagar-Gross-Krook (BGK) model “is capable of modeling shear-driven, pressure-driven, and mixed shear-pressure-driven rarified [sic] flows and heat transfer up to Kn=1 in the transitional regime” made in a recent paper [Ghazanfarian and Abbassi, Phys. Rev. E 82, 026307 (2010)]. In particular, we demonstrate that the so-called “Knudsen effects” described are merely numerical artifacts of the lattice BGK model and they are unphysical. Specifically, we show that the erroneous results for the pressure-driven flow in a microchannel imply the false and unphysical condition that 6?Kn

Li-Shi Luo

2011-10-25T23:59:59.000Z

50

Heat flow in nonlinear molecular junctions  

E-Print Network [OSTI]

We investigate the heat conduction properties of molecular junctions comprising anharmonic interactions. We find that nonlinear interactions can lead to novel phenomena: it negative differential thermal conductance and heat rectification. Based on analytically solvable models we derive an expression for the heat current that clearly reflects the interplay between anharmonic interactions, strengths of coupling to the thermal reservoirs, and junction asymmetry. This expression indicates that negative differential thermal conductance shows up when the molecule is strongly coupled to the thermal baths, even in the absence of internal molecular nonlinearities. In contrast, diode like behavior is expected for a highly anharmonic molecule with an inherent structural asymmetry. Anharmonic interactions are also necessary for manifesting Fourier type transport. We briefly present an extension of our model system that can lead to this behavior.

Dvira Segal

2005-12-22T23:59:59.000Z

51

The International Heat Flow Commission | Open Energy Information  

Open Energy Info (EERE)

The International Heat Flow Commission The International Heat Flow Commission Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: The International Heat Flow Commission Details Activities (1) Areas (1) Regions (0) Abstract: Unavailable Author(s): A. E. Beck, V. Cermak Published: Geothermics, 1989 Document Number: Unavailable DOI: Unavailable Source: View Original Journal Article Data Acquisition-Manipulation (Beck & Cermak, 1989) Unspecified Retrieved from "http://en.openei.org/w/index.php?title=The_International_Heat_Flow_Commission&oldid=387748" Category: Reference Materials What links here Related changes Special pages Printable version Permanent link Browse properties 429 Throttled (bot load) Error 429 Throttled (bot load) Throttled (bot load) Guru Meditation: XID: 1863774514

52

Temperature, heat flow maps and temperature gradient holes |...  

Open Energy Info (EERE)

Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Organization Colorado Geological Survey in Cooperation with the U.S. Department of Energy...

53

Ch. VII, Temperature, heat flow maps and temperature gradient...  

Open Energy Info (EERE)

Ch. VII, Temperature, heat flow maps and temperature gradient holes Author T. G. Zacharakis Editor T. G. Zacharakis Published Colorado Geological Survey in Cooperation with the...

54

Radiative heat transfer in a flow of rheologically complex fluid  

Science Journals Connector (OSTI)

The problem of complex radiative and convective heat transfer in steady-state generalized Couette flow of a nonlinear viscoplastic fluid is examined.

V. F. Volchenok; Z. P. Shul'man

1980-09-01T23:59:59.000Z

55

Heat Flow Database Expansion for NGDS Data Development, Collection...  

Open Energy Info (EERE)

Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Heat Flow Database Expansion for NGDS Data Development, Collection and Maintenance Project...

56

A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca  

Open Energy Info (EERE)

Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Site-Scale Model For Fluid And Heat Flow In The Unsaturated Zone Of Yucca Mountain, Nevada Details Activities (0) Areas (0) Regions (0) Abstract: A three-dimensional unsaturated-zone numerical model has been developed to simulate flow and distribution of moisture, gas and heat at Yucca Mountain, Nevada, a potential repository site for high-level radioactive waste. The model takes into account the simultaneous flow dynamics of liquid water, vapor, air and heat in the highly heterogeneous, fractured porous rock in the unsaturated zone (UZ). This model is intended for use in the prediction of the current and future conditions in the UZ so

57

Heat transfer in channel flow of a micropolar fluid  

Science Journals Connector (OSTI)

The study of heat transfer in channel flow has been done by previous authors for Newtonian and elastico-viscous fluids. It is the aim of the present ... the temperature profile for flow of a micropolar fluid in a...

Renuka Rajagopalan; K. S. Bhatnagar

1969-10-01T23:59:59.000Z

58

Heat transfer research on supercritical water flow upward in tube  

SciTech Connect (OSTI)

The experimental research of heat transfer on supercritical water has been carried out on the supercritical water multipurpose test loop with a 7.6 mm upright tube. The experimental data of heat transfer is obtained. The experimental results of thermal-hydraulic parameters on flow and heat transfer of supercritical water show that: Heat transfer enhancement occurs when the fluid temperature reaches pseudo-critical point with low mass flow velocity, and peters out when the mass flow velocity increases. The heat transfer coefficient and Nusselt number decrease with the heat flux or system pressure increases, and increase with the increasing of mass flow velocity. The wall temperature increases when the mass flow velocity decreases or the system pressure increases. (authors)

Li, H. B.; Yang, J. [China Nuclear Power Technology Research Inst., Shenzhen, Guangdong (China); Gu, H. Y.; Zhao, M. [Shanghai Jiao Tong Univ., Shanghai (China); Lu, D. H.; Zhang, J. M.; Wang, F.; Zhang, Y. [China Nuclear Power Technology Research Inst., Shenzhen, Guangdong (China)

2012-07-01T23:59:59.000Z

59

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

60

Heat transfer during laminar fluid flow in a pipe with radiative heat removal  

Science Journals Connector (OSTI)

The heat-transfer problem is analyzed for laminar fluid flow in the initial section of a ... pipe having a parabolic entry velocity distribution and heat removal by radiation from the surface of...

Ya. S. Kadaner; Yu. P. Rassadkin; É. L. Spektor

1971-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

The developing heat transfer and fluid flow in micro-channel heat sink with viscous heating effect  

Science Journals Connector (OSTI)

The numerical modeling of the conjugate heat transfer and fluid flow through the micro-heat sink was presented in the paper, considering the viscous dissipation effect. Three different fluids with temperature dep...

Dorin Lelea; Adrian Eugen Cioabla

2011-07-01T23:59:59.000Z

62

16 Heat Transfer and Air Flow in a Domestic Refrigerator  

E-Print Network [OSTI]

445 16 Heat Transfer and Air Flow in a Domestic Refrigerator Onrawee Laguerre UMR Génie Industriel........................................................................447 16.2.2 Heat Transfer and Airflow Near a Vertical Plate..................................................448 16.2.3 Heat Transfer and Airflow in Empty Closed Cavity

Paris-Sud XI, Université de

63

PIV flow measurements for heat transfer characterization in two-pass square channels with smooth and 90 ribbed walls  

E-Print Network [OSTI]

PIV flow measurements for heat transfer characterization in two-pass square channels with smooth the correlation between the high- Reynolds number turbulent flow and wall heat transfer characteristics in a two number (Re) of 30,000. The PIV measurement results were compared with the heat transfer experimental data

Kihm, IconKenneth David

64

BUBBLE CHARACTERISTICS AND CONVECTIVE EFFECTS IN THE FLOW BOILING HEAT TRANSFER OF BINARY MIXTURES  

E-Print Network [OSTI]

BUBBLE CHARACTERISTICS AND CONVECTIVE EFFECTS IN THE FLOW BOILING HEAT TRANSFER OF BINARY MIXTURES on the bubble growth and associated heat transfer phenomena. The present work focuses on obtaining the bubble. The bubble growth is observed using a high speed camera (1000 fps) under a magnification of 290X. The bubble

Kandlikar, Satish

65

Numerical Evaluation of Flow and Heat Transfer in Plate-Pin Fin Heat Sinks with Various Pin Cross-Sections  

E-Print Network [OSTI]

Liu, Research on the Heat Transfer and Flow Performance of aCompound Heat Sink, Numer. Heat Transfer A, vol. 55, no. 5,Hand- book of Numerical Heat Transfer, 2nd ed. , chap. 6,

Zhou, Feng; Catton, Ivan

2011-01-01T23:59:59.000Z

66

Heat flow and geothermal studies in the Great Plains  

SciTech Connect (OSTI)

In continental heat flow studies, sedimentary basins are usually avoided because of difficulties in obtaining thermal conductivity measurements and because temperature gradients may contain advective signals caused by moving groundwater. These problems are superimposed in the Denver, Kennedy and Williston Basins where complex geothermal gradients derive both from large contrasts among thermal conductivities of strata and from regional groundwater flow. The occurrence and magnitude of advective heat flow within the Denver, Kennedy and Williston Basins is conceptually consistent with simple models that relate groundwater flow to the piezometric surface and to subsurface structures, i.e., folds and faults. An advective heat flow of +25 mW/m/sup 2/ has been determined for an area in the eastern margin of the Denver Basin, and quantities of +35 mW/m/sup 2/ and +10 MW/m/sup 2/ have been determined respectively for parts of the southeastern and northeastern parts of the Williston Basin. A detailed analysis of bottom hole temperatures obtained from drill holes in the area of the Billings Anticline in the Williston Basin indicates that information on subsurface structures and groundwater flow may be obtained from heat flow studies. Additional information that may be derived from these heat flow studies includes: the occurrence and nature of geothermal resources, oil source rock maturation and secondary migration of petroleum, formation and deposition of strata-bound ores. 43 references.

Gosnold, W.D.; Fischer, D.W.

1985-12-01T23:59:59.000Z

67

Heat Flow At Standard Depth | Open Energy Information  

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 » Heat Flow At Standard Depth Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow At Standard Depth Details Activities (2) Areas (1) Regions (0) Abstract: Secular and long-term periodic changes in surface temperature cause perturbations to the geothermal gradient which may be significant to depths of at least 1000 m, and major corrections are required to determine absolute values of heat flow from the Earth's interior. However, detailed climatic models remain contentious and estimates of error in geothermal gradients differ widely. Consequently, regions of anomalous heat flow which

68

Flow Dynamics and Plasma Heating of Spheromaks in SSX  

Science Journals Connector (OSTI)

We report several new experimental results related to flow dynamics and heating from single dipole-trapped spheromaks and spheromak merging studies at SSX. Single spheromaks (...Phys. Plasmas 13 1...

M. R. Brown; C. D. Cothran; D. H. Cohen; J. Horwitz; V. Chaplin

2008-06-01T23:59:59.000Z

69

Temperatures, heat flow, and water chemistry from drill holes...  

Open Energy Info (EERE)

Temperatures, heat flow, and water chemistry from drill holes in the Raft River geothermal system, Cassia County, Idaho Jump to: navigation, search OpenEI Reference LibraryAdd to...

70

FRACSTIM/I: A Fully Coupled Fluid Flow/Heat Transport and Geomechanica...  

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

FRACSTIMI: A Fully Coupled Fluid FlowHeat Transport and Geomechanical DeformationFracture Generation Simulator FRACSTIMI: A Fully Coupled Fluid FlowHeat Transport and...

71

Scale effects on flow boiling heat transfer in microchannels: A fundamental perspective  

E-Print Network [OSTI]

pattern transitions and stability for flow boiling of water and FC-77 are evaluated. From the insight between heat transfer around a nucleating bubble in pool boiling and in the elongated bubble/slug flow on the high-speed visualization and localized thermal measurements made at the base of a nucleating bubble

Kandlikar, Satish

72

Heating Cooling Flows with Weak Shock Waves  

E-Print Network [OSTI]

The discovery of extended, approximately spherical weak shock waves in the hot intercluster gas in Perseus and Virgo has precipitated the notion that these waves may be the primary heating process that explains why so little gas cools to low temperatures. This type of heating has received additional support from recent gasdynamical models. We show here that outward propagating, dissipating waves deposit most of their energy near the center of the cluster atmosphere. Consequently, if the gas is heated by (intermittent) weak shocks for several Gyrs, the gas within 30-50 kpc is heated to temperatures that far exceed observed values. This heating can be avoided if dissipating shocks are sufficiently infrequent or weak so as not to be the primary source of global heating. Local PV and viscous heating associated with newly formed X-ray cavities are likely to be small, which is consistent with the low gas temperatures generally observed near the centers of groups and clusters where the cavities are located.

W. G. Mathews; A. Faltenbacher; F. Brighenti

2005-11-05T23:59:59.000Z

73

APS high heat load monochromator  

SciTech Connect (OSTI)

This document contains the design specifications of the APS high heat load (HHL) monochromator and associated accessories as of February 1993. It should be noted that work is continuing on many parts of the monochromator including the mechanical design, crystal cooling designs, etc. Where appropriate, we have tried to add supporting documentation, references to published papers, and calculations from which we based our decisions. The underlying philosophy behind performance specifications of this monochromator was to fabricate a device that would be useful to as many APS users as possible, that is, the design should be as generic as possible. In other words, we believe that this design will be capable of operating on both bending magnet and ID beamlines (with the appropriate changes to the cooling and crystals) with both flat and inclined crystal geometries and with a variety of coolants. It was strongly felt that this monochromator should have good energy scanning capabilities over the classical energy range of about 4 to 20 keywith Si (111) crystals. For this reason, a design incorporating one rotation stage to drive both the first and second crystals was considered most promising. Separate rotary stages for the first and second crystals can sometimes provide more flexibility in their capacities to carry heavy loads (for heavily cooled first crystals or sagittal benders of second crystals), but their tuning capabilities were considered inferior to the single axis approach.

Lee, W.K.; Mills, D.

1993-02-01T23:59:59.000Z

74

Numerical Analysis of Heat Transfer and Fluid Characteristics of Flowing Liquid Nitrogen in HTS Cable  

Science Journals Connector (OSTI)

Abstract High-temperature superconducting (HTS) cable has heat intrusion from the termination including joule heat generation at the terminal joint and from the room temperature cable through the Cu current lead. According to the length of the HTS cable, this heat loss may become a considerable amount which cannot be ignored in the HTS cable system. In this study, referring to a high-voltage cable (HV cable) which was developed in M-PACC project, the effect of heat transfer at the interface between the terminal joint and LN2 in the terminal vessel (ho) on the temperature of the HTS cable were calculated and evaluated. The condition of flow in the terminal vessel was assumed to be natural convection, forced flow or static condition for evaluating this effect with various heat transfer condition. As a result, in the case of the natural convection, most of heats flow into the LN2 in the terminal vessel where the volumetric flow of the LN2 is large since ho becomes high. Accordingly, the temperature rise of the LN2 in the inner pipe of Cu former and the terminal vessel can be restricted. However, in the cases of the forced flow and the static condition, most of heats flow into the LN2 in the inner pipe where the volumetric flow of the LN2 is small since ho becomes small. Accordingly, the temperature rise of the LN2 in the inner pipe becomes high. This temperature rise of the LN2 in the inner pipe makes the temperature of the HTS conductor large resulting in remarkable increase of AC losses. Consequently, on the HV cable design, for restriction of the AC loss increase, it is expected that designing the HTS cable termination such as extending outer surface of the terminal joint for increasing of the heat inflow from the terminal joint to the LN2 in the vessel is effective.

O. Maruyama; T. Ohkuma; T. Izumi; Y. Shiohara

2014-01-01T23:59:59.000Z

75

Heat Flow And Geothermal Potential In The South-Central United States |  

Open Energy Info (EERE)

And Geothermal Potential In The South-Central United States And Geothermal Potential In The South-Central United States Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow And Geothermal Potential In The South-Central United States Details Activities (1) Areas (1) Regions (0) Abstract: Geothermal exploration is typically limited to high-grade hydrothermal reservoirs that are usually found in the western United States, yet large areas with subsurface temperatures above 150 deg. C at economic drilling depths can be found east of the Rocky Mountains. The object of this paper is to present new heat flow data and to evaluate the geothermal potential of Texas and adjacent areas. The new data show that, west of the Ouachita Thrust Belt, the heat flow values are lower than east of the fault zone. Basement heat flow values for the Palo Duro and Fort

76

Oscillating flow in a stirling engine heat exchanger  

Science Journals Connector (OSTI)

Three heat exchangers exist in modern Stirling engines: a heater, a cooler, and a regenerator. Here a study that deals principally with tubular heaters and coolers is carried out. The calculation procedure for the oscillating flow heat transfer is presented. Literature sources are studied to find the most suitable correlations by comparing them to each other and to the classical turbulent flow correlations encountered in the literature. The enhancement of heat transfer by means of a few circumferential slots inside the tubes and the pressure losses of oscillatory flow are discussed. Non-circular cross-section conduits with rectangular and triangular cross-sections are investigated and compared to the smooth circular tubes. The increment of the performance of an idealised Stirling engine with slotted heat exchanger tubes is compared to the case with smooth ones. The ratio of the gain in the shaft power and pumping losses is 2.22. The Carnot efficiency increment is 2.7%.

M. Kuosa; K. Saari; A. Kankkunen; T.-M. Tveit

2012-01-01T23:59:59.000Z

77

High Heat Flux Thermoelectric Module Using Standard Bulk Material...  

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

Heat Flux Thermoelectric Module Using Standard Bulk Material High Heat Flux Thermoelectric Module Using Standard Bulk Material Presents high heat flux thermoelectric module design...

78

Applications of the Strong Heat Transformation by Pulse Flow in the Shell and Tube Heat Exchanger  

E-Print Network [OSTI]

when it was located in the downstream, which also weakened heat exchange[5-8], (4)pulse flow might enhance or weaken heat exchange that lied on flow parameter[9-11]. This article made use of FLUENT software to numerical Simulate round... exchange[12]. When adapted FLUENT software, we considered the model was slender tube which had a large gap between length and scale, so we could use double precision solver; In the numerical simulation, the pressure interpolation selected standard...

Chen, Y.; Zhao, J.

2006-01-01T23:59:59.000Z

79

The influence of a magnetic field on turbulent heat transfer of a high Prandtl number fluid  

E-Print Network [OSTI]

The influence of a magnetic field on turbulent heat transfer of a high Prandtl number fluid H magnetic field on the local and average heat transfer of an electrically conducting, turbulent fluid flow with high Prandtl number was studied experimentally. The mechanism of heat transfer modification due

Abdou, Mohamed

80

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

Open Energy Info (EERE)

of geothermal energy. As a consequence of anomalously high temperature, the mechanical lithosphere is thin and its total strength can be reduced by almost one order of...

Note: This page contains sample records for the topic "high heat flow" 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

Control of reactor coolant flow path during reactor decay heat removal  

DOE Patents [OSTI]

An improved reactor vessel auxiliary cooling system for a sodium cooled nuclear reactor is disclosed. The sodium cooled nuclear reactor is of the type having a reactor vessel liner separating the reactor hot pool on the upstream side of an intermediate heat exchanger and the reactor cold pool on the downstream side of the intermediate heat exchanger. The improvement includes a flow path across the reactor vessel liner flow gap which dissipates core heat across the reactor vessel and containment vessel responsive to a casualty including the loss of normal heat removal paths and associated shutdown of the main coolant liquid sodium pumps. In normal operation, the reactor vessel cold pool is inlet to the suction side of coolant liquid sodium pumps, these pumps being of the electromagnetic variety. The pumps discharge through the core into the reactor hot pool and then through an intermediate heat exchanger where the heat generated in the reactor core is discharged. Upon outlet from the heat exchanger, the sodium is returned to the reactor cold pool. The improvement includes placing a jet pump across the reactor vessel liner flow gap, pumping a small flow of liquid sodium from the lower pressure cold pool into the hot pool. The jet pump has a small high pressure driving stream diverted from the high pressure side of the reactor pumps. During normal operation, the jet pumps supplement the normal reactor pressure differential from the lower pressure cold pool to the hot pool. Upon the occurrence of a casualty involving loss of coolant pump pressure, and immediate cooling circuit is established by the back flow of sodium through the jet pumps from the reactor vessel hot pool to the reactor vessel cold pool. The cooling circuit includes flow into the reactor vessel liner flow gap immediate the reactor vessel wall and containment vessel where optimum and immediate discharge of residual reactor heat occurs.

Hunsbedt, Anstein N. (Los Gatos, CA)

1988-01-01T23:59:59.000Z

82

Heat Transfer at Low Temperatures between Tube Walls and Gases in Turbulent Flow  

Science Journals Connector (OSTI)

...September 1947 research-article Heat Transfer at Low Temperatures between Tube...counter-flow system to study heat transfer between tube walls and gases at...Determinations on friction accompanying heat transfer with gases in turbulent flow at...

1947-01-01T23:59:59.000Z

83

Numerical Analysis of Fluid Flow and Heat Transfer within Grooved Flat Mini Heat Pipes  

Science Journals Connector (OSTI)

A Theoretical study is carried out in order to verify the Mini Heat Pipe (MHP) concept for cooling high ... as an integrated part of a Flat Mini Heat Pipe (FMHP). Hence, a detailed ... with axial microchannels is...

Jed Mansouri; Samah Maalej; Mohamed Sassi…

2013-01-01T23:59:59.000Z

84

Brine flow in heated geologic salt.  

SciTech Connect (OSTI)

This report is a summary of the physical processes, primary governing equations, solution approaches, and historic testing related to brine migration in geologic salt. Although most information presented in this report is not new, we synthesize a large amount of material scattered across dozens of laboratory reports, journal papers, conference proceedings, and textbooks. We present a mathematical description of the governing brine flow mechanisms in geologic salt. We outline the general coupled thermal, multi-phase hydrologic, and mechanical processes. We derive these processes' governing equations, which can be used to predict brine flow. These equations are valid under a wide variety of conditions applicable to radioactive waste disposal in rooms and boreholes excavated into geologic salt.

Kuhlman, Kristopher L.; Malama, Bwalya

2013-03-01T23:59:59.000Z

85

Heat flow and microearthquake studies, Coso Geothermal Area, China Lake,  

Open Energy Info (EERE)

and microearthquake studies, Coso Geothermal Area, China Lake, and microearthquake studies, Coso Geothermal Area, China Lake, California. Final report Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Book: Heat flow and microearthquake studies, Coso Geothermal Area, China Lake, California. Final report Details Activities (2) Areas (1) Regions (0) Abstract: The present research effort at the Coso Geothermal Area located on the China Lake Naval Weapons Center, China Lake, California, was concerned with: (1) heat flow studies and (2) microearthquake studies associated with the geothermal phenomena in the Coso Hot Springs area. The sites for ten heat flow boreholes were located primarily using the available seismic ground noise and electrical resistivity data. Difficulty was encountered in the drilling of all of the holes due to altered, porous,

86

Heat flow studies, Coso Geothermal Area, China Lake, California. Technical  

Open Energy Info (EERE)

studies, Coso Geothermal Area, China Lake, California. Technical studies, Coso Geothermal Area, China Lake, California. Technical report Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Heat flow studies, Coso Geothermal Area, China Lake, California. Technical report Details Activities (1) Areas (1) Regions (0) Abstract: Heat flow studies in the Coso Geothermal Area were conducted at China Lake, California. Temperature measurements were completed in nine of the heat flow boreholes. Temperatures were measured at five meter intervals from the ground surface to the deepest five meter interval. Subsequently, temperatures were remeasured two or three times in each borehole in order to demonstrate that equilibrium thermal conditions existed. The maximum difference in temperature, at any of the five meter intervals, was 0.03 deg

87

Boiling heat transfer in a vertical microchannel: Local estimation during flow boiling with a non intrusive method  

E-Print Network [OSTI]

Boiling heat transfer in a vertical microchannel: Local estimation during flow boiling with a non the results of experimental and numerical studies concerning boiling heat transfer inside vertical in minichannels for several gravity levels (µg, 1g, 2g). To fully understand the high heat transfer potential

88

Numerical Study of Convective Heat Transfer in Flat Tube Heat Exchangers Operating in Self-Sustained Oscillatory Flow Regimes  

E-Print Network [OSTI]

Laminar, two-dimensional, constant-property numerical simulations of flat tube heat exchanger devices operating in flow regimes in which self-sustained oscillations occur were performed. The unsteady flow regimes were transition flow regimes...

Fullerton, Tracy

2012-02-14T23:59:59.000Z

89

Coupled flow and heat transfer in viscoelastic fluid with Cattaneo–Christov heat flux model  

Science Journals Connector (OSTI)

Abstract This letter presents a research for coupled flow and heat transfer of an upper-convected Maxwell fluid above a stretching plate with velocity slip boundary. Unlike most classical works, the new heat flux model, which is recently proposed by Christov, is employed. Analytical solutions are obtained by using the homotopy analysis method (HAM). The effects of elasticity number, slip coefficient, the relaxation time of the heat flux and the Prandtl number on velocity and temperature fields are analyzed. A comparison of Fourier’s Law and the Cattaneo–Christov heat flux model is also presented.

Shihao Han; Liancun Zheng; Chunrui Li; Xinxin Zhang

2014-01-01T23:59:59.000Z

90

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect (OSTI)

We investigate the mechanism of friction-induced fluid heating in nanoconfinements. Molecular dynamics simulations are used to study the temperature variations of liquid helium in nanoscale Poiseuille flows. It is found that the fluid heating is dominated by different sources of friction as the external driving force is changed. For small external force, the fluid heating is mainly caused by the internal viscous friction in the fluid. When the external force is large and causes fluid slip at the surfaces of channel walls, the friction at the fluid-solid interface dominates over the internal friction in the fluid and is the major contribution to fluid heating. An asymmetric temperature gradient in the fluid is developed in the case of nonidentical walls and the general temperature gradient may change sign as the dominant heating factor changes from internal to interfacial friction with increasing external force.

Li Zhigang [Department of Mechanical Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2010-05-21T23:59:59.000Z

91

Relationship Between Heat Flows and Geological Structures in the Sichuan Basin, P.R. China  

SciTech Connect (OSTI)

Based on an extensive data collection and analysis, this research has provided reliable representations of the features of the geothermal fields, their heat flow, and relationships with geological structures in the Sichuan Basin. The isotherms below a depth of 1,000 m show high values in the Central Uplift and the Southwest Uplift, and low values in the Northwest and Southeast Depressions. These features probably indicate undulation of crystalline basement and structural depression. At depths greater than 3,000 m, the isotherms tend to become simpler and regionalized. The mean heat flow in the basin is 69.1 mW/m{sup 2}. In the Central Uplift, the Northwest Depression and the East of the basin, heat-flow values range from 58.6 to 71.2 mW/m{sup 2}, with a mean value of 66.1 mWE/m{sup 2}. In the south and southwest, it varies from 76.6 to 100.5 mW/m{sup 2}, with a mean value of 86.2 mW/m{sup 2}. High heat-flow values occur within the uplift of the crystalline basement in the southwest Sichuan, and the heat flow decreases from the south, through the central area, to the northwest.

Zeng, Y.; Yu, H.; Wang, X.

1995-01-01T23:59:59.000Z

92

Supersonic combustion of a transverse injected H sub 2 jet in a radio frequency heated flow  

SciTech Connect (OSTI)

The combustion of a single hydrogen jet, normally injected into a radio frequency (RF) heated, oxidant-containing, supersonic flow, has been established to characterize the chemical and fluid dynamic phenomena associated with the reaction process and ultimately validate the predictive capability of computational computer dynamic (CFD) codes. The experimental system employed for this study is unique in that it uses an electrodeless, inductively coupled plasma tube to generate the high temperature oxidant-containing gas for subsequent nozzle expansion. Advantages of an RF heated flow system include reduced free-stream chemical contamination, continuous operation, and relative ease of integration into a typical flow laboratory environment. A description of the system utilized for this study is presented including preliminary results of the reactive flow characterization. In addition, the use of the laser-based diagnostic techniques, such as planar laser-induced fluorescence (PLIF), for measuring flow properties is also discussed. 8 refs., 7 figs.

Wantuck, P.J.; Tennant, R.A.; Watanabe, H.H.

1991-01-01T23:59:59.000Z

93

Heat-Flow Below the Oceans  

Science Journals Connector (OSTI)

... oceans. His two values of 22 and 26 metres per degree Centigrade give an average geothermal gradient of about 42 C./km., which he says is unexpectedly high1.

A. E. BENFIELD

1950-03-18T23:59:59.000Z

94

Effect of refrigerant charge, duct leakage, and evaporator air flow on the high temerature performance of air conditioners and heat pumps.  

E-Print Network [OSTI]

??An experimental study was conducted to quantify the effect of several installation items on the high outdoor ambient temperature performance of air conditioners. These installation… (more)

Rodriguez, Angel Gerardo

2012-01-01T23:59:59.000Z

95

Flow-induced vibration of component cooling water heat exchangers  

SciTech Connect (OSTI)

This paper presents an evaluation of flow-induced vibration problems of component cooling water heat exchangers in one of Taipower's nuclear power stations. Specifically, it describes flow-induced vibration phenomena, tests to identify the excitation mechanisms, measurement of response characteristics, analyses to predict tube response and wear, various design alterations, and modifications of the original design. Several unique features associated with the heat exchangers are demonstrated, including energy-trapping modes, existence of tube-support-plate (TSP)-inactive modes, and fluidelastic instability of TSP-active and -inactive modes. On the basis of this evaluation, the difficulties and future research needs for the evaluation of heat exchangers are identified. 11 refs., 19 figs., 3 tabs.

Yeh, Y.S.; Chen, S.S. (Taiwan Power Co., Taipei (Taiwan). Nuclear Engineering Dept.; Argonne National Lab., IL (USA))

1990-01-01T23:59:59.000Z

96

On flow and supply temperature control in district heating systems  

Science Journals Connector (OSTI)

This paper discusses how the control of the flow and the supply temperature in district heating systems can be optimized, utilizing stochastic modelling, prediction and control methods. The main objective is to reduce heat production costs and heat losses in the transmission and distribution net by minimizing the supply temperature at the district heating plant. This control strategy is reasonable, in particular, if the heat production takes place at a combined heat and power (CHP) plant. The control strategy is subject to some restrictions, e.g. that the total heat requirement for all consumers is supplied at any time, and each individual consumer is guaranteed some minimum supply temperature at any time. Another important restriction is that the variation in time of the supply temperature is kept as small as possible. This concept has been incorporated in the program package, PRESS, developed at the Technical University of Denmark. PRESS has been applied and tested, e.g. at Vestkraft in Esbjerg, Denmark, and significant saving potentials have been documented. PRESS is now distributed by the Danish District Heating Association.

Henrik Madsen; Ken Sejling; Henning T. Søgaard; Olafur P. Palsson

1994-01-01T23:59:59.000Z

97

The heating of the cooling flow (The feedback effervescent heating model)  

E-Print Network [OSTI]

The standard cooling flow model has predicted a large amount of cool gas in the clusters of galaxies. The failure of the Chandra and XXM-Newton telescopes to detect cooling gas (below 1-2 keV) in clusters of galaxies has suggested that some heating process must work to suppress the cooling. The most likely heating source is the heating by AGNs. There are many heating mechanisms, but we will adopt the effervescent heating model which is a result of the interaction of the bubbles inflated by AGN with the intra-cluster medium(ICM). Using the FLASH code, we have carried out time dependent simulations to investigate the effect of the heating on the suppression of the cooling in cooling flow clusters. We have found that the effervescent heating model can not balance the radiative cooling and it is an artificial model. Furthermore, the effervescent heating is a function of the ICM pressure gradient but the cooling is proportional to the gas density square and square root of the gas temperature.

Nasser Mohamed Ahmed

2007-10-10T23:59:59.000Z

98

Estimates of heat flow from Cenozoic seafloor using global depth and age data  

E-Print Network [OSTI]

-independent estimate of the total heat output of Cenozoic seafloor is 18.6 to 20.5 TW, which leads to a global output: Oceanic heat flow; Global heat budget; Subsidence rate 1. Introduction The total heat output of the EarthEstimates of heat flow from Cenozoic seafloor using global depth and age data Meng Wei , David

Sandwell, David T.

99

Effect of refrigerant charge, duct leakage, and evaporator air flow on the high temerature performance of air conditioners and heat pumps  

E-Print Network [OSTI]

An experimental study was conducted to quantify the effect of several installation items on the high outdoor ambient temperature performance of air conditioners. These installation items were: improper amount of refrigerant charge, reduced...

Rodriguez, Angel Gerardo

2012-06-07T23:59:59.000Z

100

High Performance Trays and Heat Exchangers in Heat Pumped Distillation Columns  

E-Print Network [OSTI]

AND LIQUID now PATHS fOA IltO TltAYS I A number of engineering contractors and 1 operating companies have employed Union Carbide'\\s High Flux and Multiple Downcomer tray technolog~es to improve performance, decrease utilities and I lower operating costs... ? Fi,?'d as nll\\ximum within hf'l~ht n'!:-;tl'ie-tlon. The control scheme for a heat pump can be de signed to be no more complex than a conventional steam/cooling water system which relies on flow and level controllers to set the various column flow...

Wisz, M. W.; Antonelli, R.; Ragi, E. G.

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Experimental study of fluid flow and heat transfer in tortuous microchannels.  

E-Print Network [OSTI]

??Tortuous microchannels have attracted increasing interest due to great potential to enhance fluid mixing and heat transfer. While the fluid flow and heat transfer in… (more)

Dai, Zhenhui

2014-01-01T23:59:59.000Z

102

Heat transfer and pressure drop of supercritical carbon dioxide flowing in several printed circuit heat exchanger channel patterns  

SciTech Connect (OSTI)

Closed-loop Brayton cycles using supercritical carbon dioxide (SCO{sub 2}) show potential for use in high-temperature power generation applications including High Temperature Gas Reactors (HTGR) and Sodium-Cooled Fast Reactors (SFR). Compared to Rankine cycles SCO{sub 2} Brayton cycles offer similar or improved efficiency and the potential for decreased capital costs due to a reduction in equipment size and complexity. Compact printed-circuit heat exchangers (PCHE) are being considered as part of several SCO{sub 2} Brayton designs to further reduce equipment size with increased energy density. Several designs plan to use a gas cooler operating near the pseudo-critical point of carbon dioxide to benefit from large variations in thermophysical properties, but further work is needed to validate correlations for heat transfer and pressure-drop characteristics of SCO{sub 2} flows in candidate PCHE channel designs for a variety of operating conditions. This paper presents work on experimental measurements of the heat transfer and pressure drop behavior of miniature channels using carbon dioxide at supercritical pressure. Results from several plate geometries tested in horizontal cooling-mode flow are presented, including a straight semi-circular channel, zigzag channel with a bend angle of 80 degrees, and a channel with a staggered array of extruded airfoil pillars modeled after a NACA 0020 airfoil with an 8.1 mm chord length facing into the flow. Heat transfer coefficients and bulk temperatures are calculated from measured local wall temperatures and local heat fluxes. The experimental results are compared to several methods for estimating the friction factor and Nusselt number of cooling-mode flows at supercritical pressures in millimeter-scale channels. (authors)

Carlson, M. [Univ. of Wisconsin - Madison, 839 Engineering Research Building, 1500 Engineering Drive, Madison, WI 53706 (United States); Kruizenga, A. [Sandia National Laboratory (United States); Anderson, M.; Corradini, M. [Univ. of Wisconsin - Madison, 839 Engineering Research Building, 1500 Engineering Drive, Madison, WI 53706 (United States)

2012-07-01T23:59:59.000Z

103

Particle Heating by Alfvenic Turbulence in Hot Accretion Flows  

E-Print Network [OSTI]

Recent work on Alfvenic turbulence by Goldreich & Sridhar (1995; GS) suggests that the energy cascades almost entirely perpendicular to the local magnetic field. As a result, the cyclotron resonance is unimportant in dissipating the turbulent energy. Motivated by the GS cascade, we calculate the linear collisionless dissipation of Alfven waves with frequencies much less than the proton cyclotron frequency, but with perpendicular wavelengths of order the Larmor radius of thermal protons. In plasmas appropriate to hot accretion flows (proton temperature much greater than electron temperature) the dissipated Alfven wave energy primarily heats the protons. For a plasma with $\\beta \\lsim 5$, however, where $\\beta$ is the ratio of the gas pressure to the magnetic pressure, the MHD assumptions utilized in the GS analysis break down before most of the energy in Alfven waves is dissipated; how the cascade then proceeds is unclear. Hot accretion flows, such as advection dominated accretion flows (ADAFs), are expected to contain significant levels of MHD turbulence. This work suggests that, for $\\beta \\gsim 5$, the Alfvenic component of such turbulence primarily heats the protons. Significant proton heating is required for the viability of ADAF models. We contrast our results on particle heating in ADAFs with recent work by Bisnovatyi-Kogan & Lovelace (1997).

Eliot Quataert

1997-10-13T23:59:59.000Z

104

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the reinforcing member and having a strengthening member wrapped around the refractory material. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Harkins, Bruce D. (San Diego, CA); Ward, Michael E. (Poway, CA)

1999-01-01T23:59:59.000Z

105

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures.

Harkins, Bruce D. (San Diego, CA); Ward, Michael E. (Poway, CA)

1998-01-01T23:59:59.000Z

106

High pressure ceramic heat exchanger  

DOE Patents [OSTI]

Many recuperators have components which react to corrosive gases and are used in applications where the donor fluid includes highly corrosive gases. These recuperators have suffered reduced life, increased service or maintenance, and resulted in increased cost. The present header assembly when used with recuperators reduces the brittle effect of a portion of the ceramic components. Thus, the present header assembly used with the present recuperator increases the life, reduces the service and maintenance, and reduces the increased cost associated with corrosive action of components used to manufacture recuperators. The present header assembly is comprised of a first ceramic member, a second ceramic member, a strengthening reinforcing member being in spaced relationship to the first ceramic member and the second ceramic member. The header assembly is further comprised of a refractory material disposed in contacting relationship with the first ceramic member, the second ceramic member and the strengthening reinforcing member. The present header assembly provides a high strength load bearing header assembly having good thermal cycling characteristics, good resistance to a corrosive environment and good steady state strength at elevated temperatures. 5 figs.

Harkins, B.D.; Ward, M.E.

1998-09-22T23:59:59.000Z

107

Flow and heat transfer around a linear array of spheres  

SciTech Connect (OSTI)

Laminar fluid flow and forced convection heat transfer over equally space linear arrays of spheres are analyzed using the finite element package FIDAP. For the arrays, sphere spacings of 1.5, 2, and 3 diameters are examined at Reynolds numbers of 40, 80, and 120 and Prandtl numbers ranging from 0.73 to 7.3. Average Nusselt numbers and drag coefficient data for a linear array of eight spheres (as an approximation to the developing region) and a single sphere with periodic boundary conditions (as an approximation to fully developed flow) are presented and correlated.

Lloyd, B. (Marathon Oil Co., Shreveport, LA (United States)); Boehn, R. (Univ. of Nevada, Las Vegas, NV (United States). Mechanical Engineering Dept.)

1994-08-01T23:59:59.000Z

108

The regional geothermal heat flow regime of the north-central Gulf of Mexico continental slope.  

E-Print Network [OSTI]

??Eighty-eight oil and gas wells located in the Texas-Louisiana continental slope were analyzed to obtain heat flow and geothermal gradient values. Present-day geothermal heat flow… (more)

Jones, Michael S

2003-01-01T23:59:59.000Z

109

A visualization comparison of convective flow boiling heat transfer augmentation devices  

E-Print Network [OSTI]

The qualitative effects of inset-table heat transfer phics. augmentation devices on vertical in-tube convective flow boiling flow regimes, transition mechanisms, and heat transfer are presented in this study. Three twisted tapes with twist ratios...

Lundy, Brian Franklin

2012-06-07T23:59:59.000Z

110

A numerica1 study of fluid flow and heat transfer in different microchannel heat sinks for electronic chip cooling  

Science Journals Connector (OSTI)

Four different microchannel heat sinks are designed to study the effects of structures in microchannel heat sinks for electronic chips cooling. Based on the theoretic analysis and numerical computation of flow...

Shanglong Xu; Guangxin Hu; Jie Qin…

2012-04-01T23:59:59.000Z

111

Melting heat transfer effects on stagnation point flow of micropolar fluid saturated in porous medium with internal heat generation (absorption)  

Science Journals Connector (OSTI)

The effect of melting heat transfer on the two dimensional boundary layer flow of a micropolar fluid near a stagnation point embedded in a porous medium in the presence of internal heat generation/absorption is i...

M. A. A. Mahmoud; S. E. Waheed

2014-08-01T23:59:59.000Z

112

3D Numerical heat transfer and fluid flow analysis in plate-fin and tube heat exchangers with electrohydrodynamic enhancement  

Science Journals Connector (OSTI)

Three-dimensional laminar fluid flow and heat transfer over a four-row plate-fin and tube heat exchanger with electrohydrodynamic (EHD) wire electrodes...V E...=0–16 kV) are investigated in detail...

Chia-Wen Lin; Jiin-Yuh Jang

2005-05-01T23:59:59.000Z

113

Heat transfer to a fluid flowing in an annulus  

E-Print Network [OSTI]

. ii I ~ DIMENSIONS AND SYMBOLS o ~ ~ ~ . ~ ~ ~ ~ I II e INTRODUCTION AND THEORY ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3 IXI e APPARATUS AND PROCEDURES ~ ~ e ~ ~ ~ ~ ~ ~ ~ ~ 7 XV o RESULTS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ e ~ ~ ~ ~ 17 V, DXSCUSSION OF RESULTS... of times 0 Prandtl nnnber~ e~& dimensionless initial temperature oi' surfaoe and fluids% D equivalent diameter& Di g~ L Q - volume flow rate~ L3/T V~ mass velooity, FT/L3 6 mass floe rate~ FT/L IMTRODUCTIOR AND THEORY This thesis comprises heat tz...

Logan, Earl

2012-06-07T23:59:59.000Z

114

Effects of lithospheric rigidity on ocean floor bathymetry and heat flow  

SciTech Connect (OSTI)

The observed quasi-rigid behaviour of surface plates in the course of their relative motion is a consequence of the high viscosity which obtains in the cold near surface region. By assigning a particular constant velocity as the upper boundary condition in a numerical model of mantle convection, we have investigated the effect of lithospheric rigidity on the variation of oceanic bathymetry and heat flow as a function of ocean floor age. Predicted variations of both bathymetry and heat flow at the surface of mantle wide convection cells which are partially heated from within, exhibit the same qualitative behaviour as data compiled for the major ocean basins. The bathymetry varies with distance x from the spreading centre initially as x/sup 1/2/ but subsequently flattens with respect to an x/sup 1/2/ reference curve whereas the heat flow closely follows an x-/sup 1/2/ decay over most of the convection cell. Consequently the viability of the mechanism for sea floor flattening proposed by Jarvis and Peltier (1980) is increased when a constant surface velocity, characteristic of rigid plates, is incorporated in the model. This model successfully predicts both that the bathymetry should flatten and that the heat flow should not.

Jarvis, G.T.; Peltier, W.R.

1981-08-01T23:59:59.000Z

115

Protected Loss of Flow Transient Simulation (Quicktime format, High  

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

Engineering Analysis > Videos Engineering Analysis > Videos Engineering Analysis: Protected Loss of Flow Transient Simulation Quicktime format Quicktime Format - High Bandwidth | Size: 25.94 MB | Bit Rate: 1148 kbps Keywords: flow transient, plot, EBR-II, SAS4A, SASSYS-1, passive safety, protected loss of flow, PLOF, shutdown heat removal test, SHRT-17, SHRT17 Elevation plot showing detailed top of core temperatures in experimental assembly XX09 during a protected loss of flow transient in EBR-II. Surrounding assemblies are depicted using fuel average temperatures. Results show excellent decay heat removal capability of sodium through natural circulation and exceptionally low transient temperatures with metallic fuel. :: Please wait until video loads completely :: Closed Captioning Transcript

116

Heat transport by laminar boundary layer flow with polymers  

E-Print Network [OSTI]

Motivated by recent experimental observations, we consider a steady-state Prandtl-Blasius boundary layer flow with polymers above a slightly heated horizontal plate and study how the heat transport might be affected by the polymers. We discuss how a set of equations can be derived for the problem and how these equations can be solved numerically by an iterative scheme. By carrying out such a scheme, we find that the effect of the polymers is equivalent to producing a space-dependent effective viscosity that first increases from the zero-shear value at the plate then decreases rapidly back to the zero-shear value far from the plate. We further show that such an effective viscosity leads to an enhancement in the drag, which in turn leads to a reduction in heat transport.

Roberto Benzi; Emily S. C. Ching.; Vivien W. S. Chu

2011-04-23T23:59:59.000Z

117

NUMERICAL SIMULATIONS OF HEAT TRANSFER AND FLUID FLOW PROBLEMS USING AN  

E-Print Network [OSTI]

NUMERICAL SIMULATIONS OF HEAT TRANSFER AND FLUID FLOW PROBLEMS USING AN IMMERSED-BOUNDARY FINITE of the immersed boundary technique for simulating fluid flow and heat transfer problems over or inside complex. Several phenomenologically different fluid flow and heat transfer problems are simulated using

Pacheco, Jose Rafael

118

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based  

E-Print Network [OSTI]

Numeric Simulation of Heat Transfer and Electrokinetic Flow in an Electroosmosis-Based Continuous is dedicated to under- standing the fluid flow and heat transfer mechanisms occurring in continuous flow PCR are discussed in detail. The importance of each heat transfer mechanism for different situations is also

Le Roy, Robert J.

119

FliHy experimental facilities for studying open channel turbulent flows and heat transfer  

E-Print Network [OSTI]

FliHy experimental facilities for studying open channel turbulent flows and heat transfer B. Freeze) facility was constructed at UCLA to study open channel turbulent flow and heat transfer of low supercritical flow regimes (Fr /1), in which the surface waves are amplified and heat transfer is enhanced due

Abdou, Mohamed

120

FLIHY EXPERIMENTAL FACILITIES FOR STUDYING OPEN CHANNEL TURBULENT FLOWS AND HEAT TRANSFER  

E-Print Network [OSTI]

1 FLIHY EXPERIMENTAL FACILITIES FOR STUDYING OPEN CHANNEL TURBULENT FLOWS AND HEAT TRANSFER B was constructed at UCLA to study open channel turbulent flow and heat transfer of low-thermal and low supercritical flow regimes (Fr>1), in which the surface waves are amplified and heat transfer is enhanced due

California at Los Angeles, University of

Note: This page contains sample records for the topic "high heat flow" 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

Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a  

E-Print Network [OSTI]

Numerical simulations of heat transfer in plane channel flow Najla EL GHARBI 1, 3, a , Rafik ABSI 2 abenzaoui@gmail.com Keywords: turbulent flows, heat transfer, forced convection, low Reynolds number model data for Re = 150. Introduction Turbulent flow with heat transfer mechanism is of great importance from

Paris-Sud XI, Université de

122

Heat transfer in the flow of a viscoelastic fluid over a stretching sheet  

Science Journals Connector (OSTI)

The problem of heat transfer in the viscoelastic fluid flow over a stretching sheet is examined. ... such as the skin-friction coefficient and the heat transfer coefficient, are determined. It is found that the heat

P. Sam Lawrence; Dr. B. Nageswara Rao

1992-01-01T23:59:59.000Z

123

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

E-Print Network [OSTI]

for Simulating Fluid Flow and Heat Transfer in Unsaturatedcomplex multiphase fluid flow and heat-transfer processes.of the coupled fluid-flow and heat-transfer processes has

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

2005-01-01T23:59:59.000Z

124

Flow and heat transfer of a third grade fluid past an exponentially stretching sheet with  

E-Print Network [OSTI]

Flow and heat transfer of a third grade fluid past an exponentially stretching sheet with partial-Newtonian boundary layer flow and heat transfer over an exponentially stretch- ing sheet with partial slip boundary. The heat transfer analysis has been carried out for two heating processes, namely (i) with prescribed sur

Paris-Sud XI, Université de

125

High heat flow in southern Tibet  

Science Journals Connector (OSTI)

... rate from fission track analyses in Himalayan rocks3. The Tibetan plateau is characterized by strong geothermal activity with numerous boiling springs, ... activity with numerous boiling springs, hot springs and even geysers scattered over most of its area4. Because the rheology of ...

Jean Francheteau; Claude Jaupart; Shen Xian Jie; Kang Wen-Hua; Lee De-Lu; Bai Jia-Chi; Wei Hung-Pin; Deng Hsia-Yeu

1984-01-05T23:59:59.000Z

126

Heat flow patterns of the North American continent: A discussion of the DNAG Geothermal Map of North America  

SciTech Connect (OSTI)

The large and small-scale geothermal features of the North American continent and surrounding ocean areas illustrated on the new 1:5,000,000 DNAG Geothermal Map of North America are summarized. Sources for the data included on the map are given. The types of data included are heat flow sites coded by value, contours of heat flow with a color fill, areas of major groundwater effects on regional heat flow, the top-of-geopressure in the Gulf Coast region, temperature on the Dakota aquifer in the midcontinent, location of major hot springs and geothermal systems, and major center of Quaternary and Holocene volcanism. The large scale heat flow pattern that is well known for the conterminous United States and Canada of normal heat flow east of the Cordillera and generally high heat flow west of the front of the Cordillera dominates the continental portion of the map. However, details of the heat flow variations are also seen and are discussed briefly in this and the accompanying papers.

Blackwell, David D.; Steele, John L.; Carter, Larry C.

1990-01-01T23:59:59.000Z

127

A general heat transfer correlation for non-boiling gasliquid flow with different flow patterns  

E-Print Network [OSTI]

, such as oil wells and pipelines, solar collectors, chemical reactors, and nuclear reactors, and its in horizontal pipes Jae-yong Kim, Afshin J. Ghajar * School of Mechanical and Aerospace Engineering, Oklahoma patterns in horizontal pipes is proposed. In order to overcome the effect of flow pattern on heat transfer

Ghajar, Afshin J.

128

Convective flow and heat transfer of a viscous heat generating fluid in the presence of a moving, infinite, vertical, porous plate  

Science Journals Connector (OSTI)

The analysis of convective flow and heat transfer of a viscous heat generating fluid past a uniformly moving, infinite, vertical, ... of the plate-motion and the presence of heat generation/absorption on the flow...

K. Vajravelu

1978-09-01T23:59:59.000Z

129

Lattice Boltzmann method for rarefied channel flows with heat transfer  

Science Journals Connector (OSTI)

Abstract A thermal lattice Boltzmann method (TLBM) is presented for the analysis of fluid flow and heat transfer in two-dimensional channels with non-continuum effects. The relaxation times ( ? f , ? g ) are linked to the Knudsen number which accounts for the rarefaction that can be present at micro geometries or at low density conditions. The TLBM used here employs inlet/outlet boundary conditions to generate a forced convection problem where the calculation of equilibrium distributions at the wall surfaces are modified to incorporate the velocity slip and temperature jump conditions. Numerical simulations are obtained for thermal micro-Couette and thermal micro-Poiseuille channel flows and the effect of the Knudsen number on the velocity and temperature profile is investigated.

Seckin Gokaltun; George S. Dulikravich

2014-01-01T23:59:59.000Z

130

Numerical heat conduction in hydrodynamical models of colliding hypersonic flows  

E-Print Network [OSTI]

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

Parkin, E R

2010-01-01T23:59:59.000Z

131

Review of fluid flow and convective heat transfer within rotating disk cavities  

E-Print Network [OSTI]

Review of fluid flow and convective heat transfer within rotating disk cavities with impinging jet * Corresponding author : souad.harmand@univ-valenciennes.fr Abstract Fluid flow and convective heat transfer, are treated in details in this review. The review focuses on convective heat transfer in predominantly outward

Boyer, Edmond

132

Review of fluid flow and convective heat transfer within rotating disk cavities  

E-Print Network [OSTI]

1 Review of fluid flow and convective heat transfer within rotating disk cavities with impinging axial direction #12;5 Introduction Fluid flow and convective heat transfer in rotor-stator configuration heat transfer in rotor-stator configurations, which are of great importance in different engineering

Paris-Sud XI, Université de

133

Numerical modeling of fluid flow and heat transfer in a narrow Taylor-Couette-Poiseuille system  

E-Print Network [OSTI]

Numerical modeling of fluid flow and heat transfer in a narrow Taylor-Couette-Poiseuille system S [1, 2] widely validated in various rotor-stator cavities with throughflow [3­5] and heat transfer [6: RANS modeling, Reynolds Stress Model, Taylor-Couette-Poiseuille flow, turbulence, heat transfer. hal

Paris-Sud XI, Université de

134

The effects of topology upon fluid-flow and heat-transfer within cellular copper structures  

E-Print Network [OSTI]

The effects of topology upon fluid-flow and heat-transfer within cellular copper structures J. Tian February 2004 Available online 20 March 2004 Abstract The fluid-flow and heat-transfer features of cellular and packed beds, but also a function of orientation (open area ratio). The overall heat transfer depends

Wadley, Haydn

135

The effects of topology upon fluid-flow and heat-transfer within cellular copper structures  

E-Print Network [OSTI]

1 The effects of topology upon fluid-flow and heat-transfer within cellular copper structures J The fluid-flow and heat-transfer features of copper cellular metal structures made by the transient liquid media. The experimental results for pressure drop and heat transfer were expressed on the basis

Wadley, Haydn

136

Finite element solutions of heat transfer in molten polymer flow in tubes with viscous dissipation  

E-Print Network [OSTI]

Finite element solutions of heat transfer in molten polymer flow in tubes with viscous dissipation the results of finite element analysis of a heat transfer problem of flowing polymer melts in a tube­Nusselt problem 1. Introduction Heat transfer to incompressible viscous non-Newto- nian fluids is a problem

Wei, Dongming

137

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow  

E-Print Network [OSTI]

Friction and Heat Transfer Characteristics of Silica and CNT Nanofluids in a Tube Flow MILIVOJE M@niu.edu * www.kostic.niu.edu Abstract: - An apparatus for exploring friction and heat transfer characteristics flow. Initial turbulent friction and heat transfer measurements for silica and carbon nanotube (CNT

Kostic, Milivoje M.

138

Flow Boiling Heat Transfer Coefficient In Minichannels Correlation and Trends Satish G. Kandlikar  

E-Print Network [OSTI]

Flow Boiling Heat Transfer Coefficient In Minichannels ­ Correlation and Trends Satish G. Kandlikar York 14623, USA The flow boiling heat transfer in small diameter passages is being applied in many boiling heat transfer coefficient with the correlations developed for conventional channels. It is found

Kandlikar, Satish

139

Global weak solutions to magnetic fluid flows with nonlinear Maxwell-Cattaneo heat transfer law  

E-Print Network [OSTI]

Global weak solutions to magnetic fluid flows with nonlinear Maxwell-Cattaneo heat transfer law F transfer in a magnetic fluid flow under the action of an applied magnetic field. Instead of the usual heat-Cattaneo law, heat transfer, magnetic field, magnetization AMS subject classifications: 76N10, 35Q35. 1

Boyer, Edmond

140

Measurements of Film Flow Rate in Heated Tubes with Various Axial Power Distributions  

E-Print Network [OSTI]

Measurements of Film Flow Rate in Heated Tubes with Various Axial Power Distributions by Carl, Measurements of Film Flow Rate in Heated Tubes with Various Axial Power Distributions KTH Nuclear Reactor power is limited by a phenomenon called critical heat flux (CHF). It appears as a sudden detoriation

Haviland, David

Note: This page contains sample records for the topic "high heat flow" 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

Continued development of a semianalytical solution for two-phase fluid and heat flow in a porous medium  

SciTech Connect (OSTI)

Over the past few years the authors have developed a semianalytical solution for transient two-phase water, air, and heat flow in a porous medium surrounding a constant-strength linear heat source, using a similarity variable {eta} = r/{radical}t. Although the similarity transformation approach requires a simplified geometry, all the complex physical mechanisms involved in coupled two-phase fluid and heat flow can be taken into account in a rigorous way, so that the solution may be applied to a variety of problems of current interest. The work was motivated by adverse to predict the thermohydrological response to the proposed geologic repository for heat-generating high-level nuclear wastes at Yucca Mountain, Nevada, in a partially saturated, highly fractured volcanic formation. The paper describes thermal and hydrologic conditions near the heat source; new features of the model; vapor pressure lowering; and the effective-continuum representation of a fractured/porous medium.

Doughty, C.; Pruess, K. [Lawrence Berkeley Lab., CA (United States)

1991-06-01T23:59:59.000Z

142

Heat transfer characteristics of circular impinging jet arrays in an annular section with cross flow effects  

E-Print Network [OSTI]

. . Heat transfer and Flutd flow results ? Counter flow . 32 64 CONCLUSIONS . 101 REFERENCES . 104 APPENDIX A. APPENDIX B APPENDIX C LIST OF FIGURES FIGURE 1 Detailed Schematic of the Test Section with the Flow Loop for 81. 27cm Inner pipe... with Parallel Flow. . 2 Schematic Diagram showing the arrangement of the mner pipes with different diameters with the copper segments. 3 Schematic of the test section showmg the two different flow arrangements (Parallel Flow and Counter Flow) . Page 12 14...

Mhetras, Shantanu Prakash

2012-06-07T23:59:59.000Z

143

Heat transfer deterioration in tubes caused by bulk flow acceleration due to thermal and frictional influences  

SciTech Connect (OSTI)

Severe deterioration of forced convection heat transfer can be encountered with compressible fluids flowing through strongly heated tubes of relatively small bore as the flow accelerates and turbulence is reduced because of the fluid density falling (as the temperature rises and the pressure falls due to thermal and frictional influence). The model presented here throws new light on how the dependence of density on both temperature and pressure can affect turbulence and heat transfer and it explains why the empirical equations currently available for calculating effectiveness of forced convection heat transfer under conditions of strong non-uniformity of fluid properties sometimes fail to reproduce observed behaviour. It provides a criterion for establishing the conditions under which such deterioration of heat transfer might be encountered and enables heat transfer coefficients to be determined when such deterioration occurs. The analysis presented here is for a gaseous fluid at normal pressure subjected strong non-uniformity of fluid properties by the application of large temperature differences. Thus the model leads to equations which describe deterioration of heat transfer in terms of familiar parameters such as Mach number, Reynolds number and Prandtl number. It is applicable to thermal power plant systems such as rocket engines, gas turbines and high temperature gas-cooled nuclear reactors. However, the ideas involved apply equally well to fluids at supercritical pressure. Impairment of heat transfer under such conditions has become a matter of growing interest with the active consideration now being given to advanced water-cooled nuclear reactors designed to operate at pressures above the critical value. (authors)

Jackson, J. D. [Univ. of Manchester, Manchester (United Kingdom)

2012-07-01T23:59:59.000Z

144

The Influence of Proposed Repository Thermal Load on Multiphase Flow and Heat Transfer in the Unsaturated Zone of Yucca Mountain  

E-Print Network [OSTI]

development of fluid flow and heat transfer models at otherTOUGH2 code [22]. Fluid flow and heat-transfer processes inand heat transfer through fractured rock is based on the DKM method. This approach considers global fluid and

Wu, Y.-S.; Mukhopadhyay, Sumit; Zhang, Keni; Bodvarsson, G.S.

2006-01-01T23:59:59.000Z

145

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect (OSTI)

This paper provides an overview of the variable refrigerant flow heat pump computer model included with the Department of Energy's EnergyPlusTM whole-building energy simulation software. The mathematical model for a variable refrigerant flow heat pump operating in cooling or heating mode, and a detailed model for the variable refrigerant flow direct-expansion (DX) cooling coil are described in detail.

Raustad, Richard A. [Florida Solar Energy Center

2013-01-01T23:59:59.000Z

146

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

E-Print Network [OSTI]

Numerical study of high heat ¯ux pool boiling heat transfer Ying He a,*, Masahiro Shoji b , Shigeo simulation model of boiling heat transfer is proposed based on a numerical macrolayer model [S. Maruyama, M. Shoji, S. Shimizu, A numerical simulation of transition boiling heat transfer, in: Proceedings

Maruyama, Shigeo

147

Heat Flow Database Expansion for NGDS Data Development, Collection and  

Open Energy Info (EERE)

Database Expansion for NGDS Data Development, Collection and Database Expansion for NGDS Data Development, Collection and Maintenance Geothermal Project Jump to: navigation, search Last modified on July 22, 2011. Project Title Heat Flow Database Expansion for NGDS Data Development, Collection and Maintenance Project Type / Topic 1 Recovery Act: Geothermal Technologies Program Project Type / Topic 2 Geothermal Data Development, Collection, and Maintenance Project Description In particular the efforts on document and core digitization, the recovery of the BEG geopressure data developed during the approximately $200 million project by DOE in the 1970-1980, the EGS data from the Fenton Hill experiments, and meta-data associated with US thermal mapping are crucial to be performed at this point because they are otherwise in danger of deterioration or complete loss.

148

Colorado: Isothermal Battery Calorimeter Quantifies Heat Flow, Helps Make Safer, Longer-lasting Batteries  

Broader source: Energy.gov [DOE]

Partnered with NETZSCH, the National Renewable Energy Laboratory (NREL) developed an Isothermal Battery Calorimeter (IBC) used to quantify heat flow in battery cells and modules.

149

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations  

E-Print Network [OSTI]

Ad hoc continuum-atomistic thermostat for modeling heat flow in molecular dynamics simulations J 2004) An ad hoc thermostating procedure that couples a molecular dynamics (MD) simulation

Brenner, Donald W.

150

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

151

Heat transfer in the nonisothermal flow of an anomalously viscous fluid in a helical duct  

Science Journals Connector (OSTI)

The problem of heat transfer in the initial section of a helical ... with a steady flow of an anomalously viscous fluid is solved numerically.

A. I. Mumladze; Yu. G. Nazmeev; O. V. Maminov

1982-08-01T23:59:59.000Z

152

Heat Flow Database Expansion for NGDS Data Development, Collection and Maintenance (SMU)  

Broader source: Energy.gov [DOE]

Heat Flow Database Expansion for NGDS Data Development, Collection and Maintenance (SMU) presentation at the April 2013 peer review meeting held in Denver, Colorado.

153

FRACSTIM/I: A Fully Coupled Fluid Flow/Heat Transport and Geomechanica...  

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

FRACSTIMI: A Fully Coupled Fluid FlowHeat Transport and Geomechanical DeformationFracture Generation Simulator aka FALCON: Fracturing and Liquid CONservation Robert K....

154

Heat and mass transfer on MHD heat generating flow through a porous medium in a rotating fluid  

Science Journals Connector (OSTI)

The problem of the free-convection flow of a viscous heat generating fluid through porous media in a rotating frame of reference is considered for the case when a strong magnetic field is imposed in a directio...

P. C. Ram

155

Experimental Study on Heat Transfer of Single-Phase Flow and Boiling Two-Phase Flow in Vertical Narrow Annuli  

SciTech Connect (OSTI)

Water single-phase and nucleate boiling heat transfer were experimentally investigated in vertical annuli with narrow gaps. The experimental data about water single-phase flow and boiling two-phase flow heat transfer in narrow annular channel were accumulated by two test sections with the narrow gaps of 1.0 mm and 1.5 mm. Empirical correlations to predict the heat transfer of the single-phase flow and boiling two-phase flow in the narrow annular channel were obtained, which were arranged in the forms of the Dittus-Boelter for heat transfer coefficients in a single-phase flow and the Jens-Lottes formula for a boiling two-phase flow in normal tubes, respectively. The mechanism of the difference between the normal channel and narrow annular channel were also explored. From experimental results, it was found that the turbulent heat transfer coefficients in narrow gaps are nearly the same to the normal channel in the experimental range, and the transition Reynolds number from a laminar flow to a turbulent flow in narrow annuli was much lower than that in normal channel, whereas the boiling heat transfer in narrow annular gap was greatly enhanced compared with the normal channel. (authors)

Suizheng Qiu; Guanghui Su; Dounan Jia [Xi'an Jiaotong University, No.28, Xianning West Road, Xi'an, Shaanxi, 710049 (China); Minoru Takahashi [Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152 (Japan)

2002-07-01T23:59:59.000Z

156

Heat and Mass Transfer in the MHD Flow of a Visco-elastic Fluid in a Rotating Porous Channel with Radiative Heat  

Science Journals Connector (OSTI)

This paper deals with heat and mass transfer in the magnetohydrodynamic flow of a visco-elastic fluid in a rotating porous channel with radiative heat. The flow phenomenon has been characterized by the fluid para...

M. Jena; M. Goswami; S. Biswal

2014-12-01T23:59:59.000Z

157

High Heat Flux Thermoelectric Module Using Standard Bulk Material  

Broader source: Energy.gov [DOE]

Presents high heat flux thermoelectric module design for cooling using a novel V-shaped shunt configuration with bulk TE elements achieving high area packing fractions

158

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

E-Print Network [OSTI]

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

Zevenhoven, Ron

159

Comparison of the high temperature heat flux sensor to traditional heat flux gages under high heat flux conditions.  

SciTech Connect (OSTI)

Four types of heat flux gages (Gardon, Schmidt-Boelter, Directional Flame Temperature, and High Temperature Heat Flux Sensor) were assessed and compared under flux conditions ranging between 100-1000 kW/m2, such as those seen in hydrocarbon fire or propellant fire conditions. Short duration step and pulse boundary conditions were imposed using a six-panel cylindrical array of high-temperature tungsten lamps. Overall, agreement between all gages was acceptable for the pulse tests and also for the step tests. However, repeated tests with the HTHFS with relatively long durations at temperatures approaching 1000%C2%B0C showed a substantial decrease (10-25%) in heat flux subsequent to the initial test, likely due to the mounting technique. New HTHFS gages have been ordered to allow additional tests to determine the cause of the flux reduction.

Blanchat, Thomas K.; Hanks, Charles R.

2013-04-01T23:59:59.000Z

160

Characteristics of Fluid flow and heat transfer in Shellside of Heat Exchangers with Longitudinal Flow of Shellside Fluid with Different Supporting structures  

Science Journals Connector (OSTI)

In the paper, a simplified numerical model-the periodic unit duct model was presented for the numerical simulation of shellside characteristics in heat exchanger with longitudinal flow of shellside fluid, and its...

Yongqing Wang; Qiwu Dong; Minshan Liu

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Heat Flow From Four New Research Drill Holes In The Western Cascades,  

Open Energy Info (EERE)

From Four New Research Drill Holes In The Western Cascades, From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa Details Activities (1) Areas (1) Regions (0) Abstract: Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat source coincides with the Quaternary volcanic arc, whereas the wider heat source would extend 10-30 km west of the arc. To test the models, four new heat-flow holes were sited

162

Phase change based cooling for high burst mode heat loads with temperature regulation above the phase change temperature  

DOE Patents [OSTI]

An apparatus and method for transferring thermal energy from a heat load is disclosed. In particular, use of a phase change material and specific flow designs enables cooling with temperature regulation well above the fusion temperature of the phase change material for medium and high heat loads from devices operated intermittently (in burst mode). Exemplary heat loads include burst mode lasers and laser diodes, flight avionics, and high power space instruments. Thermal energy is transferred from the heat load to liquid phase change material from a phase change material reservoir. The liquid phase change material is split into two flows. Thermal energy is transferred from the first flow via a phase change material heat sink. The second flow bypasses the phase change material heat sink and joins with liquid phase change material exiting from the phase change material heat sink. The combined liquid phase change material is returned to the liquid phase change material reservoir. The ratio of bypass flow to flow into the phase change material heat sink can be varied to adjust the temperature of the liquid phase change material returned to the liquid phase change material reservoir. Varying the flowrate and temperature of the liquid phase change material presented to the heat load determines the magnitude of thermal energy transferred from the heat load.

The United States of America as represented by the United States Department of Energy (Washington, DC)

2009-12-15T23:59:59.000Z

163

Implications of Heat Flow Studies for Geothermal Energy Prospects  

Science Journals Connector (OSTI)

There is a close interrelation between the phenomena of heat generation, storage of heat, transport of heat and the temperature field in the crust. For evaluating the geothermal energy potential of a given area t...

O. Kappelmeyer

1979-01-01T23:59:59.000Z

164

CFD analysis of the effects of the flow distribution and heat losses on the steam reforming of methanol in catalytic (Pd/ZnO) microreactors  

Science Journals Connector (OSTI)

Abstract A three-dimensional computational fluid dynamics (CFD) simulation study of the effects of the flow distribution and the heat losses on the performance of microchannels and microslits reactors for the steam reforming of methanol (SRM) over Pd/ZnO is presented. Several flow distributing headers covering a wide range of the flow diffuser expansion angle (?) have been considered. Large values of ? lead to flow maldistribution characterized by jet flow resulting in negative effects on the SRM conversion and hydrogen yield, especially for the microslits at high reaction temperatures and space velocities. Simulations have also evidenced that heat losses constitute a critical issue for microreactors operation, particularly at low space velocities. Heat losses may reach very high values, above 80–90% of the energy supplied to the microreactor, with the consequence that it may be necessary to provide up to 9 times the heat of the SRM reaction to achieve high methanol conversions.

I. Uriz; G. Arzamendi; P.M. Diéguez; F.J. Echave; O. Sanz; M. Montes; L.M. Gandía

2014-01-01T23:59:59.000Z

165

High energy density redox flow device  

DOE Patents [OSTI]

Redox flow devices are described in which at least one of the positive electrode or negative electrode-active materials is a semi-solid or is a condensed ion-storing electroactive material, and in which at least one of the electrode-active materials is transported to and from an assembly at which the electrochemical reaction occurs, producing electrical energy. The electronic conductivity of the semi-solid is increased by the addition of conductive particles to suspensions and/or via the surface modification of the solid in semi-solids (e.g., by coating the solid with a more electron conductive coating material to increase the power of the device). High energy density and high power redox flow devices are disclosed. The redox flow devices described herein can also include one or more inventive design features. In addition, inventive chemistries for use in redox flow devices are also described.

Chiang, Yet-Ming; Carter, W. Craig; Ho, Bryan Y; Duduta, Mihai; Limthongkul, Pimpa

2014-05-13T23:59:59.000Z

166

High flux heat transfer in a target environment  

E-Print Network [OSTI]

High flux heat transfer in a target environment T. Davenne High Power Targets Group Rutherford Valid for: Consider turbulent heat transfer in a 1.5mm diameter pipe ­ Dittus Boelter correlation Achenbach correlation for heat transfer in a packed bed of spheres Max power density for a sphere

McDonald, Kirk

167

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 Molecular dynamics methods in  

E-Print Network [OSTI]

2.13 HEAT TRANSFER & FLUID FLOW IN MICROCHANNELS 2.13.7-1 2.13.7 Molecular dynamics methods in microscale heat transfer Shigeo Maruyama A. Introduction In normal heat transfer and fluid flow calculations of molecules. This situation is approached in microscale heat transfer and fluid flow. Molecular level

Maruyama, Shigeo

168

Mathematical circulation model for the blood-flow-heat-loss relationship in the rat tail  

Science Journals Connector (OSTI)

A mathematical model for the heat-loss-blood-flow relationship is developed for the rat tail. When supplied with experimental values of heat loss and blood flow, the model allows one to compute the distribution of flow in deep and cutaneous vessels as a function of body core and tail temperature and to determine the savings in heat loss that result from alterations in the pattern of circulation and from counter-current heat transfer. Blood flow in the cutaneous and deep lying veins of the tail is controlled by both central and local temperatures and increases fairly linearly with deep body temperature. However, the distribution of blood flow in the tail is controlled only by local tail temperature and is independent of deep body temperature. The change in venous distribution of flow has a great impact on the conservation of heat and can reduce the heat loss from the circulating blood by more than 50% when venous return is directed to deep lying veins. On the other hand, counter-current heat transfer is of only minor importance in the control of heat loss from the tail, resulting at most in a 10% saving of heat loss, and that only at the smallest rate of blood flow.

E R Raman; V J Vanhuyse; M F Roberts

1987-01-01T23:59:59.000Z

169

Regional variations of heat flow differences with depth in Alberta, Canada  

Science Journals Connector (OSTI)

......occupies the vast area between the Rocky Mountain Foothills in the SW...increases toward the west from the flat plains area to the foothills and the Rocky Mountains beyond. 3 Heat flow...features, and so the heat flow in ROCKY ' MOUNTAINS INTERIOR PLAINS......

J. A. Majorowicz; F. W. Jones; H.-L. Lam; A. M. Jessop

1985-05-01T23:59:59.000Z

170

NUMERICAL STUDY OF FLUID FLOW AND HEAT TRANSFER OVER A SERIES OF IN-LINE NONCIRCULAR  

E-Print Network [OSTI]

NUMERICAL STUDY OF FLUID FLOW AND HEAT TRANSFER OVER A SERIES OF IN-LINE NONCIRCULAR TUBES CONFINED, Texas A&M University, College Station, Texas, USA Two-dimensional steady developing fluid flow and heat-volume technique. Grid independence study was carried out by running the developed code for several different grid

Bahaidarah, Haitham M.

171

Numerical study of fluid flow and heat transfer characteristics in an intermittent turbulent impinging round jet  

Science Journals Connector (OSTI)

Abstract The flow structure and heat transfer of the air pulsed turbulent impinging jet are studied numerically. The gas turbulence is modelled with the Reynolds stress model. The effects of pulse frequency, ratio of on time to total cycle time, distance between pipe outlet and impinging flat plate and Reynolds number on heat transfer are numerically studied. The impingement heat transfer increases with distance from the pipe edge and target surface. The heat transfer decreases at high distance from the pipe edge and target surface. An increase in the Reynolds number causes reduction of heat transfer enhancement. Reduced heat transfer in comparison with the steady-state impinging jet is typical in the range of low frequencies of the pulse impinging jet.

M.A. Pakhomov; V.I. Terekhov

2015-01-01T23:59:59.000Z

172

Taylor bubble-train flows and heat transfer in the context of Pulsating Balkrishna Mehta, Sameer Khandekar  

E-Print Network [OSTI]

Taylor bubble-train flows and heat transfer in the context of Pulsating Heat Pipes Balkrishna Mehta Nusselt number Heat transfer enhancement a b s t r a c t Understanding the performance of Pulsating Heat Pipes (PHPs) requires spatio-temporally coupled, flow and heat transfer information during the self

Khandekar, Sameer

173

Heat transfer and pressure drop data for high heat flux densities to water at high subcritical pressures  

E-Print Network [OSTI]

Local surface ooeffioients of heat t-ansfer, overall pressure drop data and mean friction factor are presented for heat flamms up to 3.52106 BtuAr ft2 for water flowing in a nickel tabe isder the following conditions: mass ...

Rohsenow, Warren M.

1951-01-01T23:59:59.000Z

174

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

E-Print Network [OSTI]

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

Mark A. Peletier; Frank Redig; Kiamars Vafayi

2014-03-19T23:59:59.000Z

175

Geothermal Resource-Reservoir Investigations Based On Heat Flow And Thermal  

Open Energy Info (EERE)

Resource-Reservoir Investigations Based On Heat Flow And Thermal Resource-Reservoir Investigations Based On Heat Flow And Thermal Gradient Data For The United States Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Geothermal Resource-Reservoir Investigations Based On Heat Flow And Thermal Gradient Data For The United States Details Activities (2) Areas (2) Regions (0) Abstract: Several activities related to geothermal resources in the western United States are described in this report. A database of geothermal site-specific thermal gradient and heat flow results from individual exploration wells in the western US has been assembled. Extensive temperature gradient and heat flow exploration data from the active exploration of the 1970's and 1980's were collected, compiled, and synthesized, emphasizing previously unavailable company data. Examples of

176

Heat flow in the northern Basin and Range province | Open Energy  

Open Energy Info (EERE)

in the northern Basin and Range province in the northern Basin and Range province Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Heat flow in the northern Basin and Range province Abstract The heat flow in the Basin and Range province of northern Nevada is extremely complex. It is a product of superposition of the regional effects of extension and volcanism /intrusion modified by the local conductive effects of thermal refraction (complicated structural settings),variations in radioactive heat production, erosion and sedimentation. In addition to these conductive effects,groundwater flow, both on a local and a regional basis,affects heat-flow measurements. Typical heat -flow values for the Basin and Range province average 85 +/- 10 mWm-2. The higher estimates are

177

Flow-Induced Deformation of a Flexible Thin Structure as Manifestation of Heat Transfer Enhancement  

E-Print Network [OSTI]

Flow-induced deformation of thin structures coupled with convective heat transfer has potential applications in energy harvesting and is important for understanding functioning of several biological systems. We numerically demonstrate large-scale flow-induced deformation as an effective passive heat transfer enhancement technique. An in-house, strongly-coupled fluid-structure interaction (FSI) solver is employed in which flow and structure solvers are based on sharp-interface immersed boundary and finite element method, respectively. In the present work, we validate convective heat transfer module of the in-house FSI solver against several benchmark examples of conduction and convective heat transfer including moving structure boundaries. The thermal augmentation is investigated as well as quantified for the flow-induced deformation of an elastic thin plate attached to lee side of a rigid cylinder in a heated channel laminar flow. We show that the wake vortices past the plate sweep higher sources of vorticity...

Soti, Atul Kumar; Sheridan, John

2015-01-01T23:59:59.000Z

178

Numerical investigation of flow structure and mixed convection heat transfer of impinging radial and axial jets  

SciTech Connect (OSTI)

Mixed convection flow fields and heat transfer of partially enclosed axial and radial laminar jets impinging on a heated flat plate have been investigated from the numerical solution of incompressible unsteady Navier-Stokes and energy equations with a Boussinesq approximation. For mixed convection flow at Re = 200, steady flow has not been observed for either the radial or the axial jet. For the smallest Grashof number (Gr = 10,000), periodic solutions have been obtained. With Gr = 40,000 nonsteady nonperiodic (chaotic) flow appears. Free convection may increase that heat transfer by more than 200%.

Potthast, F.; Laschefski, H.; Mitra, N.K. (Ruhr-Univ. Bochum (Germany). Inst. fuer Thermo- und Fluiddynamik); Biswas, G. (Indian Inst. of Tech., Kanpur (India). Dept. of Mechanical Engineering)

1994-08-01T23:59:59.000Z

179

Laclede Gas Company - Residential High Efficiency Heating Rebate Program |  

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

Residential High Efficiency Heating Rebate Residential High Efficiency Heating Rebate Program Laclede Gas Company - Residential High Efficiency Heating Rebate Program < Back Eligibility Multi-Family Residential Residential Savings Category Heating & Cooling Commercial Heating & Cooling Heating Appliances & Electronics Water Heating Maximum Rebate Heating System: 2 maximum Programmable Thermostats: 2 maximum Multi-Family Property Owners: 50 thermostat rebates, 50 furnace rebates over the life of the program Program Info State Missouri Program Type Utility Rebate Program Rebate Amount Gas Furnace: $150 - $200 Gas Boiler: $150 Programmable Setback Thermostat: $25 Gas Water Heater: $50 - $200 Provider Laclede Gas Company Laclede Gas Company offers various rebates to residential customers for investing in energy efficient equipment and appliances. Residential

180

Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow  

E-Print Network [OSTI]

Numerical modeling of heat transfer and fluid flow in rotor-stator cavities with throughflow S in a rotor-stator cavity subjected to a superimposed throughflow with heat transfer. Nu- merical predictions field from the heat transfer process. The turbulent flux is approximated by a gradient hypothesis

Boyer, Edmond

Note: This page contains sample records for the topic "high heat flow" 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

Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a,  

E-Print Network [OSTI]

Heat transfer and friction characteristics of air flow in microtubes Chien-Yuh Yang a, , Chia September 2011 Keywords: Microtube Heat transfer Liquid Crystal Thermography a b s t r a c t Several researches dealing with the single-phase forced convection heat transfer inside microchannels have been

Kandlikar, Satish

182

Heat transfer in the flow of a cold, axisymmetric jet over a hot sphere  

E-Print Network [OSTI]

The heat transfer characteristics of thin film flow over a hot sphere resulting from a cold vertical jet of liquid falling onto the surface has been investigated. The underlying physical features have been illustrated by numerical solutions of high accuracy based on the modified Keller box method. The solutions for film thickness distribution are good agreement with those obtained approximately by using the Pohlhausen integral momentum technique and observed experimentally by using water as working fluid, thus providing a basic confirmation of the validity of the results presented.

Shu, Jian-Jun

2014-01-01T23:59:59.000Z

183

ARC-HEATED GAS FLOW EXPERIMENTS FOR HYPERSONIC PROPULSION  

E-Print Network [OSTI]

was extensively developed for the purpose of eventually performing experiments simulating scramjet engine flow

Texas at Arlington, University of

184

DEVELOPMENT OF A HIGH PERFORMANCE COLD CLIMATE HEAT PUMP  

SciTech Connect (OSTI)

The primary goals of the proposed project were to develop, test, and evaluate a high performance and cost-effective vapor compression air-source heat pump for use in cold climate regions. Vapor compression heat pumps are a proven technology, and have been used for many years to meet heating requirements for buildings in residential, commercial, and industrial applications. However, in climate regions that experience very low outdoor ambient temperatures both the heating capacity and coefficient of performance (COP) of traditional air-source vapor compression heat pumps drops dramatically with a decrease in the outdoor air temperature. The efficiency of heat pumping equipment has improved substantially over the past 20 years; however, the efficiencies of the highest rated equipment on the market are approaching practical limits that cannot be surpassed without modifications to the basic cycle and possibly the use of additional hardware. In this report, three technologies to improve the efficiency of vapor compression systems are described. These are a) vapor injected compression, b) oil flooded compression and c) hybrid flow control of the evaporator. Compressor prototypes for both, oil flooded and vapor injected compression were developed by Emerson Climate Technologies. For the oil flooded compressor, the oil injection port location was optimized and an internal oil separator was added using several design iterations. After initial testing at Emerson Climate Technologies, further testing was done at Purdue University, and compressor models were developed. These models were then integrated into a system model to determine the achievable improvement of seasonal energy efficiency (SEER) for Minneapolis (Minnesota) climate. For the oil flooded compression, a 34% improvement in seasonal energy efficiency was found while a 21% improvement in seasonal energy efficiency ratio was found for the vapor injected compression. It was found that one benefit of both tested compression technologies is a lower discharge temperature, which allows for continued operation at lower ambient temperatures. A bin analysis of the vapor injected prototype cold climate heat pump predicts a 6% improvement in HSPF for Minneapolis. This improvement is mainly a result of the increased capacity of the system for active vapor injection. For the oil flooded system, a slightly larger performance improvement is predicted, in this case mostly caused by an increase in heating COP. Based on an economic analysis of these results, the maximum additional cost of the system changes, for the Minneapolis location, are $430 for the vapor injected system and $391 for the oil flooded system. These estimates assume that a 3-year simple payback period is accepted by the customer. For the hybrid flow control of evaporators, a new type of balancing valve was developed together with Emerson Climate technologies to reduce the cost of the control scheme. In contrast to conventional stepper motor valves, this valve requires less cables and can be driven by a cheaper output circuit on the control board. The correct valve size was determined in a dedicated test stand in several design iterations. The performance benefits of the hybrid control of the evaporator coil were determined for clean coil conditions as well as with partial blockage of the air inlet grille and under frosting conditions. For clean coil conditions, the benefits in terms of COP and capacity are negligible. However, significant benefits were noted for severely air-maldistributed operating conditions. For the H2-test, the maximum COP improvement of 17% along with a capacity improvement of nearly 40% was observed. Overall, the hybrid control scheme leads to a significant amount of performance improvement, if the air inlet conditions to the evaporator are maldistributed.

Horton, W. Travis [Purdue University] [Purdue University; Groll, Eckhard A. [Purdue University] [Purdue University; Braun, James E. [Purdue University] [Purdue University

2014-06-01T23:59:59.000Z

185

High Efficiency Microturbine with Integral Heat Recovery - Presentatio...  

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

High Efficiency Microturbine with Integral Heat Recovery - Fact Sheet, 2014 2011 CHPIndustrial Distributed Energy R&D Portfolio Review - Summary Report AMO Peer Review,...

186

Analysis of cross-flow mixed convection with applications to building heat transfer  

SciTech Connect (OSTI)

A numerical simulation model has been developed for partial enclosure with restricted inlet and outlet simulating the building fluid flow and heat transfer scenario. Computed results are presented for a number of geometric configurations over a wide range of Reynolds and Rayleigh numbers and validated with available experimental data. The physical processes were modeled by solving equations for the conservation of mass, momentum, and energy with appropriate boundary conditions. The properties of the fluid were assumed to remain approximately constant over the range of operation and the buoyancy was incorporated using the Boussinesq approximation. The k-{var_epsilon} model was used for the simulation of turbulence. The computed results included the local velocity and temperature and the variation of local heat transfer coefficient along the heated side wall. Computed results showed excellent agreement with experimental data. The flow pattern within the enclosure was found to be quite complex in nature and consisted of a core flow due to forced convection near the central region of the enclosure and strong buoyancy induced flow near the heated side walls. It was found that as the flow rate through the enclosure increased, the enhancement of heat transfer above that for natural convection alone, also increased. The variation of the local heat transfer coefficient over the heated surface was found to be strongly affected by the recirculation of portions of the forced flow within the enclosure as well as the impingement to or separation of flow from the side walls in some regions.

Gao, S.; Rahman, M.M.

1999-07-01T23:59:59.000Z

187

Parallel heat flux and flow acceleration in open field line plasmas with magnetic trapping  

SciTech Connect (OSTI)

The magnetic field strength modulation in a tokamak scrape-off layer (SOL) provides both flux expansion next to the divertor plates and magnetic trapping in a large portion of the SOL. Previously, we have focused on a flux expander with long mean-free-path, motivated by the high temperature and low density edge anticipated for an absorbing boundary enabled by liquid lithium surfaces. Here, the effects of magnetic trapping and a marginal collisionality on parallel heat flux and parallel flow acceleration are examined. The various transport mechanisms are captured by kinetic simulations in a simple but representative mirror-expander geometry. The observed parallel flow acceleration is interpreted and elucidated with a modified Chew-Goldberger-Low model that retains temperature anisotropy and finite collisionality.

Guo, Zehua; Tang, Xian-Zhu; McDevitt, Chris [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2014-10-15T23:59:59.000Z

188

Coupled Model for Heat and Water Transport in a High Level Waste Repository  

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

Coupled Model for Heat and Water Transport in a High Level Waste Coupled Model for Heat and Water Transport in a High Level Waste Repository in Salt Coupled Model for Heat and Water Transport in a High Level Waste Repository in Salt This report summarizes efforts to simulate coupled thermal-hydrological-chemical (THC) processes occurring within a generic hypothetical high-level waste (HLW) repository in bedded salt; chemical processes of the system allow precipitation and dissolution of salt with elevated temperatures that drive water and water vapor flow around hot waste packages. Characterizing salt backfill processes is an important objective of the exercise. An evidence-based algorithm for mineral dehydration is also applied in the modeling. The Finite Element Heat and Mass transfer code (FEHM) is used to simulate coupled thermal,

189

ECI International Conference on Heat Transfer and Fluid Flow in Microscale Whistler, 21-26 September 2008  

E-Print Network [OSTI]

ECI International Conference on Heat Transfer and Fluid Flow in Microscale Whistler, 21] studied convective heat transfer of slug flows in a macro-sized tube by using viscoelastic fluids-26 September 2008 NUMERICAL STUDY ON CONVECTIVE HEAT TRANSFER OF GAS-LIQUID SLUG FLOW IN A MICRO TUBE Qunwu He

Kasagi, Nobuhide

190

Bypass valve and coolant flow controls for optimum temperatures in waste heat recovery systems  

DOE Patents [OSTI]

Implementing an optimized waste heat recovery system includes calculating a temperature and a rate of change in temperature of a heat exchanger of a waste heat recovery system, and predicting a temperature and a rate of change in temperature of a material flowing through a channel of the waste heat recovery system. Upon determining the rate of change in the temperature of the material is predicted to be higher than the rate of change in the temperature of the heat exchanger, the optimized waste heat recovery system calculates a valve position and timing for the channel that is configurable for achieving a rate of material flow that is determined to produce and maintain a defined threshold temperature of the heat exchanger, and actuates the valve according to the calculated valve position and calculated timing.

Meisner, Gregory P

2013-10-08T23:59:59.000Z

191

Low GWP Working Fluid for High Temperature Heat Pumps  

E-Print Network [OSTI]

Low GWP Working Fluid for High Temperature Heat Pumps: DR-2 Chemical Stability at High Temperatures Temp Heat Pumps: DR-2 Very Low GWP AND Non-Flammable HFC-245fa DR-2 Chemical Formula CF3CH2CHF2 HFO 171.3 Pcr [MPa] 3.65 2.9 Kontomaris-DuPont; European Heat Pump Summit, Nuremberg, October 15th, 2013

Oak Ridge National Laboratory

192

Mapping Geothermal Heat Flow and Existing Plants | Department...  

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

resources make up most of the current geothermal operating plants in the United States. Power generation comes from drawing heat from the fluid found naturally deep below the...

193

Numerical modeling of deep groundwater flow and heat transport in the Williston Basin  

SciTech Connect (OSTI)

A numerical modeling approach has been used to evaluate quantitatively the effects of fluid flow on contemporary heat flow in an intracratonic basin. The authors have selected the Williston basin for this hydrodynamic study because of the opportunity it presents to assess the relation of deep groundwater flow to basin geothermics and the associated features of diagenesis and petroleum accumulation. The finite element method is used to solve the coupled equations of fluid flow and heat transport in two-dimensional sections of the basin. Both the fluid- and heat-flow regime are assumed to be at steady state, and the fluid flow is driven primarily by the water-table relief which is taken to be a subdued replica of land-surface topography. Buoyancy forces may also affect flow through fluid density gradients created by temperature and salinity effects. Three southwest-northwest oriented sections across the basin were modeled using available and estimated parameter data. The predicted flow patterns are most strongly affected by the topography, but the Devonian salt unit and Cretaceous shale unit exert some control. Cross-formational flow is especially important near the downdip, solution edge of the salt beds. Flow rates rarely exceed 0.5 m/year in the deep-central part of the basin, yet there does exist a marked effect on heat flow, albeit subdued by the blanket effect of the low-permeability Cretaceous shales. The regional effect of the topography-driven flow system is reflected in present-day salinity patterns and heat-flow data.

Garven, G.; Vigrass, L.

1985-01-01T23:59:59.000Z

194

Temperatures, heat flow, and water chemistry from drill holes in the Raft  

Open Energy Info (EERE)

Temperatures, heat flow, and water chemistry from drill holes in the Raft Temperatures, heat flow, and water chemistry from drill holes in the Raft River geothermal system, Cassia County, Idaho Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Report: Temperatures, heat flow, and water chemistry from drill holes in the Raft River geothermal system, Cassia County, Idaho Details Activities (1) Areas (1) Regions (0) Abstract: The Raft River area of Idaho contains a geothermal system of intermediate temperatures (approx. = 150 0C) at depths of about 1.5 km. Outside of the geothermal area, temperature measurements in three intermediate-depth drill holes (200 to 400 m) and one deep well (1500 m) indicate that the regional conductive heat flow is about 2.5 mucal/cm 2 sec or slightly higher and that temperature gradients range from 50 0 to 60

195

Local heat and mass transfer for gas-solid two phase flow in CFB  

Science Journals Connector (OSTI)

An experimental investigation on the flow characteristics and the local heat and mass transfer between coarse wet particles and hot gas in the circulating fluidized bed (CFB) has been performed. A two-thermocoupl...

Feng Lu; Ming-Heng Shi

1994-09-01T23:59:59.000Z

196

Heat transfer due to stagnation point flow of a non-Newtonian fluid  

Science Journals Connector (OSTI)

Heat transfer analysis for steady, laminar flow of an incompressible, homogeneous, non-Newtonian fluid of second grade at a stagnation point...K, of the fluid. The energy equation is discretized using central ......

V. K. Garg

1994-01-01T23:59:59.000Z

197

Heat-transfer mechanism in turbulent flow of fluid at supercritical pressures  

Science Journals Connector (OSTI)

A hypothetical physical model of the heat-transfer process accompanying a forced flow of liquid at supercritical pressures is proposed. This model accounts for the anomalous improvements and deteriorations in ...

Sh. G. Kaplan

1971-09-01T23:59:59.000Z

198

Second-order fluid flow past a stretching sheet with heat transfer  

Science Journals Connector (OSTI)

The heat transfer in the flow of a second-order fluid, obeying Coleman and Noll's constitutive equation...KC/v. The thermal boundary layer thickness decreases and the Nusselt numberNu x increases ...

N. M. Bujurke; S. N. Biradar; P. S. Hiremath

1987-07-01T23:59:59.000Z

199

Unsteady hydromagnetic free-convection flow with radiative heat transfer in a rotating fluid  

Science Journals Connector (OSTI)

We consider the buoyancy-induced flow of an electrically-conducting fluid with radiative heat transfer past a vertical flat plate of infinite ... vary with temperature, that is a compressible fluid. If the temper...

A. R. Bestman; S. K. Adjepong

200

Heat transfer in a radiating fluid with slug flow in a parallel-plate channel  

Science Journals Connector (OSTI)

As a step towards a better understanding of combined conduction, convection, and radiation, fully developed heat transfer in slug flow in a flat duct ... , nonblack, isothermal surfaces. The gray radiating fluid ...

R. Viskanta

1964-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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 in an MHD channel flow with boundary conditions of the third kind  

Science Journals Connector (OSTI)

The heat transfer equation for a two-dimensional magnetohydrodynamic channel flow has been solved using boundary conditions of the third kind considering a discontinuity in the “ambient” temperature. The bound...

Sergio Cuevas; Eduardo Ramos

1991-01-01T23:59:59.000Z

202

Visualization of flow boiling in an annular heat exchanger under reduced gravity conditions  

E-Print Network [OSTI]

creating unique visual and quantitative data. These data were then analyzed using a resistance type heat transfer model and five different zero gravity flow regime maps. Results from this analysis included: (i) presenting zero gravity data that correlated...

Westheimer, David Thomas

2012-06-07T23:59:59.000Z

203

Numerical study of flow and heat transfer in 3D serpentine channels using colocated grids  

E-Print Network [OSTI]

and average Nusselt number. The numerical code developed was validated by solving for fully developed flow and heat transfer in a square straight channel. Grid-independent solution was established for a reference case of serpentine channel with the highest...

Chintada, Sailesh Raju

1998-01-01T23:59:59.000Z

204

Heat Flow From Four New Research Drill Holes In The Western Cascades...  

Open Energy Info (EERE)

Four New Research Drill Holes In The Western Cascades, Oregon, Usa Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Heat Flow From Four New...

205

Influence of surface heating on the boundary layer stability of flows with favorable pressure gradients  

E-Print Network [OSTI]

INFLUENCE OF SURFACE HEATING ON THE BOUNDARY LAYER STABILITY OF FLOWS WITH FAVORABI E PRESSURE GRADIENTS A Thesis by DAVID BRIAN LANDRUM Submitted to the Graduate College of Texas AAM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1986 Major Subject: Aerospace Engineering INFLUENCE OF SURFACE HEATING ON THE BOUNDARY LAYER STABILITY OF FLOWS WITH FAVORABLE PRESSURE GRADIENTS A Thesis by DAVID BRIAN LANDRUM Approved as to style and content...

Landrum, David Brian

2012-06-07T23:59:59.000Z

206

Finite element analysis of conjugate heat transfer in axisymmetric pipe flows  

E-Print Network [OSTI]

FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MA STER... OF S CI EN CE August 1987 Major Subject: Mechanical Engineering FINITE ELEMENT ANALYSIS OF CONJUGATE HEAT TRANSFER IN AXISYMMETRIC PIPE FLOWS A Thesis by ROBERT MILLER FITHEN Approved ss to style and content by: N. K. Anand (Chairman of Committee...

Fithen, Robert Miller

2012-06-07T23:59:59.000Z

207

Characteristics of fluid flow and heat transfer in a fluidized heat exchanger with circulating solid particles  

Science Journals Connector (OSTI)

The commercial viability of heat exchanger is mainly dependent on its long- ... loss and degrades the thermal performance of a heat exchanger. An experimental study was performed to investigate the characteristic...

Soo Whan Ahn; ByungChang Lee; WonCheol Kim; Myung- Whan Bae…

2002-09-01T23:59:59.000Z

208

Saturated critical heat flux in a multi-microchannel heat sink fed by a split flow system  

SciTech Connect (OSTI)

An extensive experimental campaign has been carried out for the measurement of saturated critical heat flux in a multi-microchannel copper heat sink. The heat sink was formed by 29 parallel channels that were 199 {mu}m wide and 756 {mu}m deep. In order to increase the critical heat flux and reduce the two-phase pressure drop, a split flow system was implemented with one central inlet at the middle of the channels and two outlets at either end. The base critical heat flux was measured using three HFC Refrigerants (R134a, R236fa and R245fa) for mass fluxes ranging from 250 to 1500 kg/m{sup 2} s, inlet subcoolings from -25 to -5 K and saturation temperatures from 20 to 50 C. The parametric effects of mass velocity, saturation temperature and inlet subcooling were investigated. The analysis showed that significantly higher CHF was obtainable with the split flow system (one inlet-two outlets) compared to the single inlet-single outlet system, providing also a much lower pressure drop. Notably several existing predictive methods matched the experimental data quite well and quantitatively predicted the benefit of higher CHF of the split flow. (author)

Mauro, A.W.; Toto, D. [Department of Energetics, Applied Thermofluidynamics and Air Conditioning Systems, FEDERICO II University, p.le Tecchio 80, 80125 Napoli (Italy); Thome, J.R. [Laboratory of Heat and Mass Transfer (LTCM), Faculty of Engineering (STI), Ecole Polytechnique Federale de Lausanne (EPFL), Station 9, Lausanne CH-1015 (Switzerland); Vanoli, G.P. [Engineering Department, Sannio University, Corso Garibaldi 107, Palazzo dell'Aquila Bosco Lucarelli, 82100 Benevento (Italy)

2010-01-15T23:59:59.000Z

209

Terrestrial Heat Flow and Heat Generation in South-west England  

Science Journals Connector (OSTI)

......g cm-3 and a heat generation contrast of 3.35 pW...batholith, assuming heat generation from the country rocks...that radioactive heat generation is not constant throughout...University of London Reactor Centre for providing...from radioactivity, Nuclear Geology, ed. H. Faul......

H. Y. Tammemagi; J. Wheildon

1974-07-01T23:59:59.000Z

210

Heat transfer and pressure drop for air flow through enhanced passages  

SciTech Connect (OSTI)

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

211

Heat transfer and pressure drop for air flow through enhanced passages. Final report  

SciTech Connect (OSTI)

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

212

A Refined Model of Stationary Heat Transfer in Composite Bodies Reinforced with Pipes Containing a Heat-Transfer Fluid Moving in Laminar Flow Conditions  

Science Journals Connector (OSTI)

Equations describing the stationary heat conduction of composite bodies spatially reinforced with ... of smooth pipes, through which an incompressible heat-transfer fluid is pumped in laminar flow conditions, are...

A. P. Yankovskii

2014-03-01T23:59:59.000Z

213

Three-dimensional analysis of fluid flow and heat transfer in single- and two-layered micro-channel heat sinks  

Science Journals Connector (OSTI)

A three-dimensional numerical analysis of laminar fluid flow and conjugate heat transfer has been conducted for single- and two-layered micro-channel heat sinks. The validity of the numerical model ... power, the...

M. L.-J. Levac; H. M. Soliman; S. J. Ormiston

2011-11-01T23:59:59.000Z

214

Heat and mass transfer in a visco–elastic fluid flow over an accelerating surface with heat source/sink and viscous dissipation  

Science Journals Connector (OSTI)

...?In this paper we present a mathematical analysis of heat and mass transfer phenomena in a visco–elastic fluid flow over an accelerating stretching sheet in the presence of heat source/sink, viscous dissipatio...

R. M. Sonth; S. K. Khan; M. S. Abel; K. V. Prasad

2002-02-01T23:59:59.000Z

215

Heat transfer and temperature distribution in a turbulent flow over a flat plate with an unheated starting length  

SciTech Connect (OSTI)

The present study is a numerical investigation of heat transfer and temperature distribution in a boundary layer formed by a flow with nonzero free stream turbulence over a flat plate with an unheated starting length. The numerical method is based on the Reynolds-averaged equations of motion and energy. As a closure for the Reynolds- averaged equations the Hinze relations for turbulent shear stresses and for turbulent heat flux are used. The Hinze equations are used instead of the usually employed Boussinesq eddy-viscosity hypothesis, because the latter does not work properly for flows with high free stream turbulence. It is shown in the present study that the influence of an unheated starting length on a temperature profile has manifested itself similarly to the influence of the free stream turbulence and resulted in a temperature profile with negative profile parameter. Unlike the flow with zero free stream turbulence, a heat transfer coefficient for the part of the plate with an unheated starting length can be less than for the fully heated plate. This difference increases with increasing level of the free stream turbulence. The family of functions that describe the influence of an unheated starting length for flows with nonzero free stream turbulence is presented.

Fridman, E.

1997-07-01T23:59:59.000Z

216

On Heating of Cluster Cooling Flows by Sound Waves  

E-Print Network [OSTI]

We investigate heating of the cool core of a galaxy cluster through the dissipation of sound waves excited by the activities of the central active galactic nucleus (AGN). Using a weak shock theory, we show that this heating mechanism alone cannot reproduce observed temperature and density profiles of a cluster, because the dissipation length of the waves is much smaller than the size of the core and thus the wave energy is not distributed to the whole core. However, we find that if it is combined with thermal conduction from the hot outer layer of the cluster, the wave heating can reproduce the observational results.

Yutaka Fujita; Takeru Ken Suzuki

2005-08-10T23:59:59.000Z

217

Experimental Study of Heat Transfer and Flow Characteristics for a New Type of Air Heater  

E-Print Network [OSTI]

. It is found that the integrated characteristics of heat transfer and flow friction increase with the hole's diameter at the same hole density (which is equal to the ratio of the hole's total area to the baffle's area), and the heat transfer rate increases...

Zheng, H.; Fan, X.; Li, A.

2006-01-01T23:59:59.000Z

218

Scale and deposits in high-heat-rejection engines  

SciTech Connect (OSTI)

Scaling under conditions very similar to those of a heavy-duty diesel engine cooling system was investigated using a newly designed, versatile test stand. The parameters included flow rate, heat flux, hardness, along with bulk fluid temperatures. The hot surface temperature, a critical parameter, was also measured. Results were interpreted in terms of the conditions in the boundary layer at the hot surface. Critical values of flow rate and heat flux existed for scaling under experimental conditions. A quantitative relationship of scale with heat flux and hardness was observed. Deposits produced from testing of different types of commercial coolants, including phosphate based and nonphosphate bases, were measured and compared with results from simple beaker tests.

Chen, Y.S.; Kershisnik, E.I. [Dober Group, Glenwood, IL (United States); Hudgens, R.D. [Fleetguard, Inc., Cookeville, TN (United States); Corbeels, C.L.; Zehr, R.L. [Cummins Engine Co., Inc., Columbus, IN (United States)

1999-08-01T23:59:59.000Z

219

A method to visualise near wall fluid flow patterns using locally resolved heat transfer experiments  

Science Journals Connector (OSTI)

Abstract The present study demonstrates an alternative approach for describing fluid flow characteristics very close to the wall, using locally resolved convective heat transfer experiments. Heat transfer coefficients on the base surface and around a surface mounted vortex generator of delta-wing shape design, are evaluated with the transient liquid crystal measurement technique and over a range of freestream velocities. Therefore, the local values of exponent m in the equation Nu x ? Re x m , which is directly linked to the structure of the boundary layer, can be determined over the complete heat transfer area. The local distributions of exponent m are then directly compared to the footprint of the flow obtained with typical oil and dye surface flow visualisation. The results indicate that a more appropriate interpretation of the flow structures very close to the wall is possible by analysing the spatial variation of exponent m, which approximates better the flow pattern compared to the heat transfer coefficients. As a result, fluid flow topologies can be directly evaluated from the heat transfer experiments since the distributions of oil-flow visualisation and exponent m are qualitatively similar.

Alexandros Terzis; Jens von Wolfersdorf; Bernhard Weigand; Peter Ott

2015-01-01T23:59:59.000Z

220

An analog analysis of transient heat flow in solids with temperature-dependent thermal properties  

E-Print Network [OSTI]

) used a nonlinear material known as Metrosil to simulate the nonlinear variations of thermal properties for combined conductive and radiant heat transfer. Since that time, Friedmann (8) has used nonlinear resistances in conjunction with an electronic... at end of this thesis. K = thermal conductivity of heat conducting media, and K and S are functions of the temperature t. Since the formation of these equations, solutions of transient heat flow problems involving materials in which the thermal...

Lee, Dwain Edward

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Technical Subtopic 2.1: Modeling Variable Refrigerant Flow Heat Pump and Heat Recovery Equipment in EnergyPlus  

SciTech Connect (OSTI)

The University of Central Florida/Florida Solar Energy Center, in cooperation with the Electric Power Research Institute and several variable-refrigerant-flow heat pump (VRF HP) manufacturers, provided a detailed computer model for a VRF HP system in the United States Department of Energy's (U.S. DOE) EnergyPlus? building energy simulation tool. Detailed laboratory testing and field demonstrations were performed to measure equipment performance and compare this performance to both the manufacturer's data and that predicted by the use of this new model through computer simulation. The project goal was to investigate the complex interactions of VRF HP systems from an HVAC system perspective, and explore the operational characteristics of this HVAC system type within a laboratory and real world building environment. Detailed laboratory testing of this advanced HVAC system provided invaluable performance information which does not currently exist in the form required for proper analysis and modeling. This information will also be useful for developing and/or supporting test standards for VRF HP systems. Field testing VRF HP systems also provided performance and operational information pertaining to installation, system configuration, and operational controls. Information collected from both laboratory and field tests were then used to create and validate the VRF HP system computer model which, in turn, provides architects, engineers, and building owners the confidence necessary to accurately and reliably perform building energy simulations. This new VRF HP model is available in the current public release version of DOE?s EnergyPlus software and can be used to investigate building energy use in both new and existing building stock. The general laboratory testing did not use the AHRI Standard 1230 test procedure and instead used an approach designed to measure the field installed full-load operating performance. This projects test methodology used the air enthalpy method where relevant air-side parameters were controlled while collecting output performance data at discreet points of steady-state operation. The primary metrics include system power consumption and zonal heating and cooling capacity. Using this test method, the measured total cooling capacity was somewhat lower than reported by the manufacturer. The measured power was found to be equal to or greater than the manufacturers indicated power. Heating capacity measurements produced similar results. The air-side performance metric was total cooling and heating energy since the computer model uses those same metrics as input to the model. Although the sensible and latent components of total cooling were measured, they are not described in this report. The test methodology set the thermostat set point temperature very low for cooling and very high for heating to measure full-load performance and was originally thought to provide the maximum available capacity. Manufacturers stated that this test method would not accurately measure performance of VRF systems which is now believed to be a true statement. Near the end of the project, an alternate test method was developed to better represent VRF system performance as if field installed. This method of test is preliminarily called the Load Based Method of Test where the load is fixed and the indoor conditions and unit operation are allowed to fluctuate. This test method was only briefly attempted in a laboratory setting but does show promise for future lab testing. Since variable-speed air-conditioners and heat pumps include an on-board control algorithm to modulate capacity, these systems are difficult to test. Manufacturers do have the ability to override internal components to accommodate certification procedures, however, it is unknown if the resulting operation is replicated in the field, or if so, how often. Other studies have shown that variable-speed air-conditioners and heat pumps do out perform their single-speed counterparts though these field studies leave as many questions as they do provide answers. The measure

Raustad, Richard; Nigusse, Bereket; Domitrovic, Ron

2013-09-30T23:59:59.000Z

222

Heat source/sink effects on non-Newtonian MHD fluid flow and heat transfer over a permeable stretching surface: Lie group analysis  

Science Journals Connector (OSTI)

An analysis is performed for flow and heat transfer of a non-Newtonian fluid known as Casson fluid over a permeable stretching surface through a...

M. N. Tufail; A. S. Butt; A. Ali

2014-01-01T23:59:59.000Z

223

Study on the Application of High Temperature Heat Pump to Recover Waste Heat of Marine Diesel Engine  

Science Journals Connector (OSTI)

Being an energy-saving equipment with great development potential, high temperature heat pump is becoming one of the research hotspots in recent years. However, there is little research about the application of high temperature heat pump on ships as ... Keywords: marine diesel engine, cooling water, waste heat recovery, high temperature heat pump

Shi-jie Liu; Wu Chen; Zhen-xiong Cai; Chao-yu Zheng

2009-10-01T23:59:59.000Z

224

ORIGINAL PAPER Flow Dynamics and Plasma Heating of Spheromaks in SSX  

E-Print Network [OSTI]

ORIGINAL PAPER Flow Dynamics and Plasma Heating of Spheromaks in SSX M. R. Brown � C. D. Cothran � from single dipole- trapped spheromaks and spheromak merging studies at SSX. Single spheromaks) copper flux conserver. Local spheromak flow is studied with two Mach probes (r1 £ qi, r2 qi) calibrated

Brown, Michael R.

225

ENERGY CONCENTRATION FOR 2-DIMENSIONAL RADIALLY SYMMETRIC EQUIVARIANT HARMONIC MAP HEAT FLOWS  

E-Print Network [OSTI]

flows. Adapting Struwe's energy method we first establish a finite bubble tree result with a discrete, energy method, energy quanta, bubble tree, bubbling off, single bubble, intersection-comparison. AMSENERGY CONCENTRATION FOR 2-DIMENSIONAL RADIALLY SYMMETRIC EQUIVARIANT HARMONIC MAP HEAT FLOWS

Hulshof, Joost

226

Oscillating flow loss test results in Stirling engine heat exchangers. Final Report  

SciTech Connect (OSTI)

The results are presented for a test program designed to generate a database of oscillating flow loss information that is applicable to Stirling engine heat exchangers. The tests were performed on heater/cooler tubes of various lengths and entrance/exit configurations, on stacked and sintered screen regenerators of various wire diameters and on Brunswick and Metex random fiber regenerators. The test results were performed over a range of oscillating flow parameters consistent with Stirling engine heat exchanger experience. The tests were performed on the Sunpower oscillating flow loss rig which is based on a variable stroke and variable frequency linear drive motor. In general, the results are presented by comparing the measured oscillating flow losses to the calculated flow losses. The calculated losses are based on the cycle integration of steady flow friction factors and entrance/exit loss coefficients.

Koester, G.; Howell, S.; Wood, G.; Miller, E.; Gedeon, D.

1990-05-01T23:59:59.000Z

227

Experimental study on heat transfer to supercritical water flowing through tubes  

SciTech Connect (OSTI)

A test facility named SWAMUP (Supercritical Water Multi-Purpose Loop) has been constructed in Shanghai Jiao Tong Univ. to investigate heat transfer and pressure drop through tubes and rod bundles. SWAMUP is a closed loop with operating pressure up to 30 MPa, outlet-water temperature up to 550 deg. C, and mass flow rate up to 5 t/h. In this paper, experimental study has been carried out on heat transfer of supercritical water flowing vertically through tubes (ID=7.6 and 10 mm). A large number of test points in tubes has been obtained with a wide range of heat flux (200-1500 kw/m{sup 2}) and mass flux (450-2000 kg/m{sup 2}s). Test results showed that heat transfer deterioration (HTD) caused by buoyancy effect only appears in upward flow and HTD caused by acceleration effect appears both in upward flow and downward flow. The heat transfer coefficients (HTC) produced in tube tests were compared with existing heat transfer correlations. (authors)

Zhao, M.; Gu, H.; Cheng, X. [School of Nuclear Science and Engineering, Shanghai Jiao Tong Univ. SJTU, 800 Dongchuan Road, Shanghai (China)

2012-07-01T23:59:59.000Z

228

Heat Transfer in Wedge Flow of a Micropolar Fluid  

Science Journals Connector (OSTI)

The theory of fluids with microstructures was first given by Eringen ... , 1965), and they are called micropolar fluids. These fluids exhibit microrotational effects and microrotational inertia. The flow of such

V. M. Soundalgekar; H. S. Takhar

1980-01-01T23:59:59.000Z

229

Enhanced heat transfer using wire-coil inserts for high-heat-load applications.  

SciTech Connect (OSTI)

Enhanced heat-transfer techniques, used to significantly reduce temperatures and thermally induced stresses on beam-strike surfaces, are routinely used at the APS in all critical high-heat-load components. A new heat-transfer enhancement technique being evaluated at the APS involving the use of wire-coil inserts proves to be superior to previously employed techniques. Wire coils, similar in appearance to a common spring, are fabricated from solid wire to precise tolerances to mechanically fit inside standard 0.375-in-diameter cooling channels. In this study, a matrix of wire coils, fabricated with a series of different pitches from several different wire diameters, has been tested for heat-transfer performance and resulting pressure loss. This paper reviews the experimental data and the analytical calculations, compares the data with existing correlations, and interprets the results for APS front-end high-heat-load components.

Collins, J. T.; Conley, C. M.; Attig, J. N.; Baehl, M. M.

2002-09-20T23:59:59.000Z

230

High Average Power Laser Gain Medium With Low Optical Distortion Using A Transverse Flowing Liquid Host  

DOE Patents [OSTI]

A high average power, low optical distortion laser gain media is based on a flowing liquid media. A diode laser pumping device with tailored irradiance excites the laser active atom, ion or molecule within the liquid media. A laser active component of the liquid media exhibits energy storage times longer than or comparable to the thermal optical response time of the liquid. A circulation system that provides a closed loop for mixing and circulating the lasing liquid into and out of the optical cavity includes a pump, a diffuser, and a heat exchanger. A liquid flow gain cell includes flow straighteners and flow channel compression.

Comaskey, Brian J. (Walnut Creek, CA); Ault, Earl R. (Livermore, CA); Kuklo, Thomas C. (Oakdale, CA)

2005-07-05T23:59:59.000Z

231

Numerical analysis of vapor flow in a micro heat pipe  

E-Print Network [OSTI]

be modeled as a classical blowing and suction problem, i. e. ?(00) = v(00) = o ?(I, p) = v(L0) = 0 ?(x, 0) = ?(x, H) = 0 i(x, 0) = v(x), v(x, H) = -i'(x) 0&x&I. , (2. 6) v(x, 0) = 0, v(x, H) = 0 I. , &x&(L, +L, ) i(x, 0) = -v(x), v(x, H) = v(x) (L, +L... are considerably smoother and appear more reasonable Figure 5. 6 presents the velocity vector which is under q=40W/cm2, H=0. 003m uniform heat flux linear heat flux 0 00 0 O'I 0 02 0. 03 0. 04 0. 05 0 06 x(m) Fig. 5. 2 Heat flux distribution influence...

Liu, Xiaoqin

2012-06-07T23:59:59.000Z

232

Cedarville Elementary & High School Space Heating Low Temperature  

Open Energy Info (EERE)

Cedarville Elementary & High School Space Heating Low Temperature Cedarville Elementary & High School Space Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Cedarville Elementary & High School Space Heating Low Temperature Geothermal Facility Facility Cedarville Elementary & High School Sector Geothermal energy Type Space Heating Location Cedarville, California Coordinates 41.5290606°, -120.1732781° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}

233

Cotulla High School Space Heating Low Temperature Geothermal Facility |  

Open Energy Info (EERE)

Cotulla High School Space Heating Low Temperature Geothermal Facility Cotulla High School Space Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Cotulla High School Space Heating Low Temperature Geothermal Facility Facility Cotulla High School Sector Geothermal energy Type Space Heating Location Cotulla, Texas Coordinates 28.436934°, -99.2350322° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}

234

Henley High School Space Heating Low Temperature Geothermal Facility | Open  

Open Energy Info (EERE)

Henley High School Space Heating Low Temperature Geothermal Facility Henley High School Space Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Henley High School Space Heating Low Temperature Geothermal Facility Facility Henley High School Sector Geothermal energy Type Space Heating Location Klamath Falls, Oregon Coordinates 42.224867°, -121.7816704° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}

235

Modoc High School Space Heating Low Temperature Geothermal Facility | Open  

Open Energy Info (EERE)

Modoc High School Space Heating Low Temperature Geothermal Facility Modoc High School Space Heating Low Temperature Geothermal Facility Jump to: navigation, search Name Modoc High School Space Heating Low Temperature Geothermal Facility Facility Modoc High School Sector Geothermal energy Type Space Heating Location Alturas, California Coordinates 41.4871146°, -120.5424555° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[]}

236

Energy efficiency improvements utilising mass flow control and a ring topology in a district heating network  

Science Journals Connector (OSTI)

Abstract Heating and cooling have a major role in the energy sector, covering 46% of total final energy use worldwide. District heating (DH) is a significant technology for improving the energy efficiency of heating systems in communities, because it enables waste heat sources to be utilised economically and therefore significantly reduces the environmental impacts of power generation. As a result of new and more stringent construction regulations for buildings, the heat demands of individual buildings are decreasing and more energy-efficient heating systems have to be developed. In this study, the energy efficiency of a new DH system which includes both a new control system called mass flow control and a new network design called a ring network is examined. A topology in the Helsinki region is studied by using a commercial DH network modelling tool, Grades Heating. The district heating network is attached to a wood-burning heat station which has a heat recovery system in use. Examination is performed by means of both technical and economic analysis. The new non-linear temperature programme that is required is adopted for supply and return temperatures, which allows greater temperature cooling and smaller flow rates. Lower district heating water temperatures are essential when reducing the heat losses in the network and heat production. Mass flow control allows smaller pressure drops in the network and thus reduces the pumping power. The aim of this study was to determine the most energy-efficient DH water supply temperatures in the case network. If the ring network design is utilised, the district heating system is easier to control. As a result the total heat consumption within the heating season is reduced compared to traditional DH systems. On the basis of the results, the new DH system is significantly more energy-efficient in the case network that was examined than the traditional design. For example, average energy losses within the constraints (which consist of heat losses, pumping energy, and surplus energy from the heat recovery system) are reduced from 4.4% to 3.1%.

Tatu Laajalehto; Maunu Kuosa; Tapio Mäkilä; Markku Lampinen; Risto Lahdelma

2014-01-01T23:59:59.000Z

237

A numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat transfer at microscale  

E-Print Network [OSTI]

Computational fluid dynamics Microchannel Minichannel Surface roughness Roughness elements Heat transfer Fluid to achieve enhancement in heat transfer with relatively low cooling fluid flow rate [1]. In spite of havingA numerical study on the effects of 2d structured sinusoidal elements on fluid flow and heat

Kandlikar, Satish

238

Two-Layer Baroclinic Eddy Heat Fluxes: Zonal Flows and Energy Balance ANDREW F. THOMPSON AND WILLIAM R. YOUNG  

E-Print Network [OSTI]

Two-Layer Baroclinic Eddy Heat Fluxes: Zonal Flows and Energy Balance ANDREW F. THOMPSON of these drag- less heat-flux parameterizations relies on the ability of to direct energy into zonal flows, California (Manuscript received 27 September 2006, in final form 13 December 2006) ABSTRACT The eddy heat

Young, William R.

239

Effect of rolling motion on critical heat flux for subcooled flow boiling in vertical tube  

SciTech Connect (OSTI)

This paper presents defining characteristics of the critical heat flux (CHF) for the boiling of R-134a in vertical tube operation under rolling motion in marine reactor. It is important to predict CHF of marine reactor having the rolling motion in order to increase the safety of the reactor. Marine Reactor Moving Simulator (MARMS) tests are conducted to measure the critical heat flux using R-134a flowing upward in a uniformly heated vertical tube under rolling motion. MARMS was rotated by motor and mechanical power transmission gear. The CHF tests were performed in a 9.5 mm I.D. test section with heated length of 1 m. Mass fluxes range from 285 to 1300 kg m{sup -2}s{sup -1}, inlet subcooling from 3 to 38 deg. C and outlet pressures from 13 to 24 bar. Amplitudes of rolling range from 15 to 40 degrees and periods from 6 to 12 sec. To convert the test conditions of CHF test using R-134a in water, Katto's fluid-to-fluid modeling was used in present investigation. A CHF correlation is presented which accounts for the effects of pressure, mass flux, inlet subcooling and rolling angle over all conditions tested. Unlike existing transient CHF experiments, CHF ratio of certain mass flux and pressure are different in rolling motion. For the mass fluxes below 500 kg m{sup -2}s{sup -1} at 13, 16 (region of relative low mass flux), CHF ratio was decreased but was increased above that mass flux (region of relative high mass flux). Moreover, CHF tend to enhance in entire mass flux at 24 bar. (authors)

Hwang, J. S.; Park, I. U.; Park, M. Y.; Park, G. C. [Dept. of Energy Systems Engineering, Seoul National Univ., 599 Gwanak-Ro, Gwanak-Gu, Seoul, 151-744 (Korea, Republic of)

2012-07-01T23:59:59.000Z

240

Causal heat flow in Bianchi type-V universe  

E-Print Network [OSTI]

In this paper we investigate the role of causal heat transport in a spatially homogeneous, locally-rotationally symmetric Bianchi type-V cosmological model. In particular, the causal temperature profile of the cosmological fluid is obtained within the framework of extended irreversible thermodynamics. We demonstrate that relaxational effects can alter the temperature profile when the cosmological fluid is out of hydrostatic equilibrium.

M. Govender; S. Thirukkanesh

2014-04-11T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


241

DNS on turbulent heat transfer of viscoelastic fluid flow in a plane channel with transverse rectangular orifices  

Science Journals Connector (OSTI)

Heat-transfer characteristics of a viscoelastic turbulence past rectangular orifices were investigated in the context of the reduction effects of fluid elasticity on drag and heat transfer. To simulate the fully-developed channel flow through transverse orifices located periodically at intervals of 6.4 times channel height, we imposed periodic conditions at the upstream and downstream boundaries. To discuss the dissimilarity between the velocity and thermal fields, the molecular Prandtl number was set to be 1.0 and any temperature dependence of the fluid and rheological properties was not considered. In the present condition, the ratio of the reduction rates in drag and heat transfer was found to be 2.8:1.0, revealing that the present flow configuration is better than a smooth channel for avoiding the heat-transfer reduction. This phenomenon was attributed to the sustainment of the quasi-streamwise vortex downstream of the reattachment point despite the absence of strong spanwise vortices emanating from the orifice edge in the viscoelastic fluid. The longitudinal vortices behind the reattachment point caused a high turbulent heat flux and increased the local Nusselt number.

Takahiro Tsukahara; Tomohiro Kawase; Yasuo Kawaguchi

2013-01-01T23:59:59.000Z

242

Use Remote Sensing Data (selected visible and infrared spectrums) to locate high temperature ground anomalies in Colorado. Confirm heat flow potential with on-site surveys to drill deep resource wells  

Broader source: Energy.gov [DOE]

DOE Geothermal Technologies Peer Review 2010 - Presentation. Project Objectives: A cost effective three (3) Phased Program to locate and confirm up to Five (5) commercial geothermal resources in Colorado. The heat resources to be prioritized will be those able to support a minimum electrical generation capacity of 10 MW by location.

243

Numerical Studies of Fluid Leakage from a Geologic Disposal Reservoir for CO2 Show Self-Limiting Feedback between Fluid Flow and Heat Transfer  

E-Print Network [OSTI]

Feedback between Fluid Flow and Heat Transfer Karsten Pruessfeedback between fluid flow and heat transfer tends to limitfluid mobility (viscosity and relative permeability effects), are countered by effects arising from limitations in the rate of conductive heat transfer.

Pruess, Karsten

2005-01-01T23:59:59.000Z

244

Heat transfer during the flow of an incompressible fluid in a circular tube, allowing for axial heat flow, with boundary conditions of the first and second kind at the tube surface  

Science Journals Connector (OSTI)

An examination is made of heat transfer in a hydraulically stabilized laminar stream and in a two-layer dynamic flow model.

V. V. Shapovalov

1966-09-01T23:59:59.000Z

245

Plasma Heating by High-Current Relativistic Electron Beams  

Science Journals Connector (OSTI)

A mechanism is proposed for the heating of a plasma with a high-current relativistic electron beam which makes essential use of the plasma return current induced by the beam. From overall energy conservation it is concluded that a large fraction of the beam energy is converted into plasma thermal energy. For reasonable parameters the heating occurs through ion sound turbulence generated by the plasma return current.

R. V. Lovelace and R. N. Sudan

1971-11-08T23:59:59.000Z

246

Flow patterns and heat transfer around six in-line circular cylinders at low Reynolds number  

E-Print Network [OSTI]

The flow field and the heat transfer around six in-line iso-thermal circular cylinders has been studied by mean of numerical simulations. Two values of the center to center spacing ($s=3.6d$ and $4d$, where $d$ is the cylinder diameter) at Reynolds number of $100$ and Prandtl number of $0.7$ has been investigated. Similarly to the in-line two cylinder configuration, in this range a transition in the flow and in the heat transfer occurs. Two different flow patterns have been identified: the stable shear layer (SSL) mode and the shear layer secondary vortices (SLSV) mode, at $3.6$ and $4$ spacing ratio ($s/d$), respectively. At $s/d=3.6$ the flow pattern causes the entrainment of cold fluid on the downstream cylinders enhancing the heat transfer. On the other hand at $s/d=4$ two stable opposite shear layer prevent the cold fluid entrainment over the downstream cylinders reducing their heat exchange. The overall time average heat transfer of the array is enhanced up to 25% decreasing the spacing ratio from $4$ t...

Fornarelli, Francesco; Lippolis, Antonio

2014-01-01T23:59:59.000Z

247

3-D Numerical Simulation of Heat Transfer and Turbulent Flow in a Receiver Tube of Solar Parabolic Trough Concentrator with Louvered Twisted-tape Inserts  

Science Journals Connector (OSTI)

Abstract High temperature and higher-thermal efficiency for CSP cycles are main goals to improve trough collector's technologies. For a parabolic trough collector the major factor for optimum heat transfer from sun to the heat transfer fluid passing in the absorber tube is to have high convection heat transfer coefficient. Literature shows that absorber tubes with various tape inserts are used and recommended to produce high convection coefficient. Typical twisted-tape (TT) enhances heat exchange between tube surface and working fluid by generating turbulent swirling flow. In this study, enhancement of convection coefficient in the receiver tube of a solar parabolic trough concentrator that the absorber tube is equipped with a new perforated louvered twisted- tape (LTT) is studied numerically. For numerical simulations three different twist ratios (TR), TR=y/W= 2.67, 4, 5.33 (y is the length required for one twist and W is the width of the tape) are used in an experimental laboratory trough collector. Flow is assumed turbulent due to louvered perforated surface and rotational shape of the tape. For thermal boundary condition, non- uniform wall solar heat flux is determined by Soltrace code on the outer surface of the absorber tube. Heat transfer rate and pressure drop are determined for fully developed condition for several Reynolds numbers based on the tube diameter and flow mean velocity. Results show that the heat transfer coefficient and pressure drop increase significantly in comparison with a typical plain twisted-tape in the tube and a plain tube.

Sh. Ghadirijafarbeigloo; A.H. Zamzamian; M. Yaghoubi

2014-01-01T23:59:59.000Z

248

Woven heat exchanger  

DOE Patents [OSTI]

This invention relates to a heat exchanger for waste heat recovery from high temperature industrial exhaust streams. In a woven ceramic heat exchanger using the basic tube-in-shell design, each heat exchanger consisting of tube sheets and tube, is woven separately. Individual heat exchangers are assembled in cross-flow configuration. Each heat exchanger is woven from high temperature ceramic fiber, the warp is continuous from tube to tube sheet providing a smooth transition and unitized construction.

Piscitella, R.R.

1984-07-16T23:59:59.000Z

249

High speed flow cytometric separation of viable cells  

DOE Patents [OSTI]

Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

Sasaki, D.T.; Van den Engh, G.J.; Buckie, A.M.

1995-11-14T23:59:59.000Z

250

High speed flow cytometric separation of viable cells  

DOE Patents [OSTI]

Hematopoietic cell populations are separated to provide cell sets and subsets as viable cells with high purity and high yields, based on the number of original cells present in the mixture. High-speed flow cytometry is employed using light characteristics of the cells to separate the cells, where high flow speeds are used to reduce the sorting time.

Sasaki, Dennis T. (Mountain View, CA); Van den Engh, Gerrit J. (Seattle, WA); Buckie, Anne-Marie (Margate, GB)

1995-01-01T23:59:59.000Z

251

Effect of heat transfer on the plane-channel poiseuille flow of a thermo-viscous fluid  

Science Journals Connector (OSTI)

A steady-state plane channel flow of viscous incompressible fluid with no-slip and heat transfer boundary conditions is considered. The flow is ... induced by a fixed pressure difference and the fluid viscosity d...

S. N. Aristov; V. G. Zelenina

252

Applications of heat pipes for high thermal load beam lines  

SciTech Connect (OSTI)

The high flux beam produced by insertion devices often requires special heat removal techniques. For the optical elements used in such high thermal load beam lines, the required precision demands a highly accurate design. Heat pipe cooling of critical elements of the X-1 beam line at the National Synchrotron Light Source is described. This method reduces vibrations caused by water cooling systems and simplifies the design. In some of these designs, deposited heat must be transferred through unbonded contact interfaces. A pinhole assembly and a beam position monitor designed for the X-1 beam line both transfer heat through such interfaces in an ultrahigh vacuum environment. The fundamental design objective is that of removing the heat with minimal interface thermal resistance. We present our test method and results for measuring the thermal resistance across metallic interfaces as a function of contact pressure. The design of some devices which utilize both heat pipes and thermal contact interfaces will also be described. 12 refs., 8 figs.

Shu, D.; Mortazavi, P.; Rarback, H.; Howells, M.R.

1985-01-01T23:59:59.000Z

253

Electrically heated particulate filter with zoned exhaust flow control  

DOE Patents [OSTI]

A system includes a particulate matter (PM) filter that includes X zones. An electrical heater includes Y heater segments that are associated with respective ones of the X zones. The electrical heater is arranged upstream from and proximate with the PM filter. A valve assembly includes Z sections that are associated with respective ones of the X zones. A control module adjusts flow through each of the Z sections during regeneration of the PM filter via control of the valve assembly. X, Y and Z are integers.

Gonze, Eugene V [Pinckney, MI

2012-06-26T23:59:59.000Z

254

Interpreting Velocities from Heat-Based Flow Sensors by NumericalSimulation  

SciTech Connect (OSTI)

We have carried out numerical simulations of three-dimensional non-isothermal flow around an in situ heat-based flow sensor to investigate how formation heterogeneities can affect the interpretation of ground water flow velocities from this instrument. The flow sensor operates by constant heating of a 0.75 m long, 5 cm diameter cylindrical probe, which contains 30 thermistors in contact with the formation. The temperature evolution at each thermistor can be inverted to obtain an estimate of the ground water flow velocity vector using the standard interpretive method, which assumes that the formation is homogeneous. Analysis of data from heat-based flow sensors installed in a sand aquifer at the Former Fort Ord Army Base near Monterey, California suggested an unexpected component of downward flow. The magnitudes of the vertical velocities were expected to be much less than the horizontal velocities at this site because the sensors were installed just above a clay aquitard. Numerical simulations were conducted to examine how differences in thermal conductivities may lead to spurious indications of vertical flow velocities. We found that a decrease in the thermal conductivity near the bottom of the sensor can perturb the temperature profiles along the instrument in such a manner that analyses assuming homogeneous thermal conductivity could indicate a vertical flow component even though flow is actually horizontal. This work demonstrates how modeling can be used to simulate instrument response to formation heterogeneity, and shows that caution must be used in interpreting data from such devices using overly simplistic assumptions.

Su, Grace W.; Freifeld, Barry M.; Oldenburg, Curtis M.; Jordan,Preston D.; Daley, Paul F.

2005-06-13T23:59:59.000Z

255

High-Efficiency Quantum-Well Thermoelectrics for Waste Heat Power...  

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

High-Efficiency Quantum-Well Thermoelectrics for Waste Heat Power Generation High-Efficiency Quantum-Well Thermoelectrics for Waste Heat Power Generation 2005 Diesel Engine...

256

PBMR as an Ideal Heat Source for High-Temperature Process Heat Applications  

SciTech Connect (OSTI)

The Pebble Bed Modular Reactor (PBMR) is an advanced helium-cooled, graphite-moderated High Temperature Gas-cooled Reactor (HTGR). A 400 MWt PBMR Demonstration Power Plant (DPP) for the production of electricity is being developed in South Africa. This PBMR technology is also an ideal heat source for process heat applications, including Steam Methane Reforming, steam for Oil Sands bitumen recovery, Hydrogen Production and co-generation (process heat and/or electricity and/or process steam) for petrochemical industries. The cycle configuration used to transport the heat of the reactor to the process plant or to convert the reactor's heat into electricity or steam directly influences the cycle efficiency and plant economics. The choice of cycle configuration depends on the process requirements and is influenced by practical considerations, component and material limitations, maintenance, controllability, safety, performance, risk and cost. This paper provides an overview of the use of a PBMR reactor for process applications and possible cycle configurations are presented for applications which require high temperature process heat and/or electricity. (authors)

Correia, Michael; Greyvenstein, Renee [PBMR - Pty Ltd., 1279 Mike Crawford Avenue, Centurion, 0046 (South Africa); Silady, Fred; Penfield, Scott [Technology Insights, 6540 Lusk Blvd, Suite C-102, San Diego, California 92121 (United States)

2006-07-01T23:59:59.000Z

257

Terrestrial Heat Flow and Heat Generation in South-west England  

Science Journals Connector (OSTI)

......the Wilsey Down borehole, and of heat...located over the large underlying batholith...the Wilsey Down borehole lies just beyond...the effects of drilling had subsided and...length of the borehole, I6 months after drilling ceased. At Geevor......

H. Y. Tammemagi; J. Wheildon

1974-07-01T23:59:59.000Z

258

Buoyancy driven flow in a hot water tank due to standby heat loss  

Science Journals Connector (OSTI)

Results of experimental and numerical investigations of thermal behavior in a vertical cylindrical hot water tank due to standby heat loss of the tank are presented. The effect of standby heat loss on temperature distribution in the tank is investigated experimentally on a slim 150 l tank with a height to diameter ratio of 5. A tank with uniform temperatures and with thermal stratification is studied. A detailed computational fluid dynamics (CFD) model of the tank is developed to calculate the natural convection flow in the tank. The distribution of the heat loss coefficient for the different parts of the tank is measured by experiments and used as input to the CFD model. Water temperatures at different levels of the tank are measured and compared to CFD calculated temperatures. The investigations focus on validation of the CFD model and on understanding of the CFD calculations. The results show that the CFD model predicts satisfactorily water temperatures at different levels of the tank during cooling by standby heat loss. It is elucidated how the downward buoyancy driven flow along the tank wall is established by the heat loss from the tank sides and how the natural convection flow is influenced by water temperatures in the tank. When the temperature gradient in the tank is smaller than 2 K/m, there is a downward fluid velocity of 0.003–0.015 m/s. With the presence of thermal stratification the buoyancy driven flow is significantly reduced. The dependence of the velocity magnitude of the downward flow on temperature gradient is not influenced by the tank volume and is only slightly influenced by the tank height to tank diameter ratio. Based on results of the CFD calculations, an equation is determined to calculate the magnitude of the buoyancy driven flow along the tank wall for a given temperature gradient in the tank.

Jianhua Fan; Simon Furbo

2012-01-01T23:59:59.000Z

259

Solutions of turbulent backward-facing step flow with heat transfer using the finite volume method  

SciTech Connect (OSTI)

The heated turbulent flow over a backward-facing step is numerically solved using the commercial computational fluid dynamics program FLUENT. The methods used here consist of the default power-law upwinding scheme, default multigrid equation solution method and a standard k-{var_epsilon} turbulence model with wall functions. A total of four separate cases are reported. The four cases consist of combinations of partially and fully developed flow at the inlet with uniform or developed temperature profiles. Three mesh refinements are reported for each flow.

Horstman, R.H. [Boeing Commercial Airplane, Seattle, WA (United States). Environmental Control Systems R& D; Cochran, R.J. [Sandia National Labs., Albuquerque, NM (United States); Emergy, A.F. [Univ. of Washington, Seattle, WA (United States). Dept. of Mechanical Engineering

1995-12-31T23:59:59.000Z

260

Flow and Heat-Transfer Apparatus, Instrumentation and Data Acquisition Method  

E-Print Network [OSTI]

friction and convective heat transfer characteristics of nanofluids. Instead of a usual closed-loop system where pumps and after-cooling units are required, the developed apparatus utilizes nitrogen pressure-driven flow to test a single batch of fluid. This reduces the complexity of the system while improving its

Kostic, Milivoje M.

Note: This page contains sample records for the topic "high heat flow" 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

November 28, 2006 Seismologists get handle on heat flow deep in earth  

E-Print Network [OSTI]

November 28, 2006 Seismologists get handle on heat flow deep in earth Earth's interior placid inner Earth as a dynamic environment filled with exotic materials and substances roiling under that has an impact on what happens on our planet's surface. The latest evidence of this dynamic inner Earth

Garnero, Ed

262

Turbulent models of ice giant internal dynamics: Dynamos, heat transfer, and zonal flows  

E-Print Network [OSTI]

Turbulent models of ice giant internal dynamics: Dynamos, heat transfer, and zonal flows K Magnetic fields a b s t r a c t The ice giant planets, Uranus and Neptune, have magnetic fields to yield small-scale and disorganized turbulence. In agreement with ice giant observations, both

263

INFLUENCE OF OHMIC HEATING ON ADVECTION-DOMINATED ACCRETION FLOWS G. S. BISNOVATYI-KOGAN  

E-Print Network [OSTI]

is advected inward, and the fraction 1 f is locally radiated. The further assumption that the energy exchange that the dissipation of turbulent energy of the flow heats the ions and that the dissipated energy is advected inward. It is suggested that the efficiency of conversion of accretion energy to radiation can be very much smaller than

264

Experimental shellside flow visualization in a shell and tube heat exchanger  

E-Print Network [OSTI]

information in the shellside flow. A scale-model shell and tube heat exchanger with an outer diameter of 30.5 cm and a length of 61 cm was designed and constructed out of acrylic. Water was utilized as the working fluid and flowrates ranging from 0.32 to 2...

Fischer, Matthew Winslow

1998-01-01T23:59:59.000Z

265

Numerical simulation of fluid flow and heat transfer in a passage with moving boundary  

Science Journals Connector (OSTI)

In this paper, a method is presented in detail that can be used to solve the fluid flow and heat transfer in domains with moving boundaries. The primitive variables formulation is adopted and a non-staggered grid, with Cartesian velocity components used as the primary unkowns in the momentum equations, is utilised. Discretisation is carried out using a control-volume method, the simplified QUICK scheme combined with a deferred correction approach is adopted for the convective fluxes and implicit time stepping is used for temporal differencing. The well-known SIMPLE algorithm is employed for handling the velocityâ??pressure coupling. The computational method is applied for the prediction of fluid flow and heat transfer in a channel with a boundary moving in a prescribed manner. Results show that both the amplitude and Strouhal number have great influences on the characteristics of fluid flow and heat transfer, and in the range studied, the heat transfer rate increases monotonously with the amplitude, whereas the Strouhal number only has a small effect on heat transfer.

D. S. Zhang; Q. W. Wang; W. Q. Tao

2002-01-01T23:59:59.000Z

266

High Operating Temperature Liquid Metal Heat Transfer Fluids  

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

267

Inferring temperature uniformity from gas composition measurements in a hydrogen combustion-heated hypersonic flow stream  

SciTech Connect (OSTI)

The application of a method for determining the temperature of an oxygen-replenished air stream heated to 2600 K by a hydrogen burner is reviewed and discussed. The purpose of the measurements is to determine the spatial uniformity of the temperature in the core flow of a ramjet test facility. The technique involves sampling the product gases at the exit of the test section nozzle to infer the makeup of the reactant gases entering the burner. Knowing also the temperature of the inlet gases and assuming the flow is at chemical equilibrium, the adiabatic flame temperature is determined using an industry accepted chemical equilibrium computer code. Local temperature depressions are estimated from heat loss calculations. A description of the method, hardware and procedures is presented, along with local heat loss estimates and uncertainty assessments. The uncertainty of the method is estimated at {+-}31 K, and the spatial uniformity was measured within {+-}35 K.

Olstad, S.J. [Phoenix Solutions Co., Minneapolis, MN (United States)

1995-08-01T23:59:59.000Z

268

High-density turbidity currents: Are they sandy debris flows?  

SciTech Connect (OSTI)

Conventionally, turbidity currents are considered as fluidal flows in which sediment is supported by fluid turbulence, whereas debris flows are plastic flows in which sediment is supported by matrix strength, dispersive pressure, and buoyant lift. The concept of high-density turbidity current refers to high-concentration, commonly non-turbulent, flows of fluids in which sediment is supported mainly by matrix strength, dispersive pressure, and buoyant lift. The conventional wisdom that traction carpets with entrained turbulent clouds on top represent high-density turbidity currents is a misnomer because traction carpets are neither fluidal nor turbulent. Debris flows may also have entrained turbulent clouds on top. The traction carpet/debris flow and the overriding turbulent clouds are two separate entities in terms of flow rheology and sediment-support mechanism. In experimental and theoretical studies, which has linked massive sands and floating clasts to high-density turbidity currents, the term high-density turbidity current has actually been used for laminar flows. In alleviating this conceptual problem, sandy debris flow is suggested as a substitute for high-density turbidity current. Sandy debris flows represent a continuous spectrum of processes between cohesive and cohesionless debris flows. Commonly they are rheologically plastic. They may occur with or without entrained turbulent clouds on top. Their sediment-support mechanisms include matrix strength, dispersive pressure, and buoyant lift. They are characterized by laminar flow conditions, a moderate to high grain concentration, and a low to moderate mud content. Although flows evolve and transform during the course of transport in density-stratified flows, the preserved features in a deposit are useful to decipher only the final stages of deposition. At present, there are no established criteria to decipher transport mechanism from the depositional record.

Shanmugam, G. [Mobil Exploration and Producing Technical Center, Dallas, TX (United States)

1996-01-01T23:59:59.000Z

269

Steam reformers heated by helium from high temperature reactors  

Science Journals Connector (OSTI)

The manifold possibilities of the application of helium-heated steam reformers combined with high temperature nuclear reactors are elucidated in this article. It is shown that the thermodynamic interpretation of the processes does not cause difficulties because of the good heat transfer in helium at high pressure and that helium peak temperatures of 950°C are sufficient for carrying out the process. The mechanical design of the reformer tube does not lead to problems because the helium and process pressures are so chosen as to be approximately equal. The problems of hydrogen and tritium permeation as well as the contamination of the reformer tube with solid fission products seem to be solvable using the knowledge available at present. Furthermore, the various possibilities for the design arrangements of helium-heated reformer tube furnaces are shown. The status of development attained to date is outlined and in conclusion there is a survey regarding the next steps to be taken in steam reformer technology.

K. Kugeler; M. Kugeler; H.F. Niessen; K.H. Hammelmann

1975-01-01T23:59:59.000Z

270

Turbulent heat transfer in a channel flow at transitional Reynolds numbers  

E-Print Network [OSTI]

Direct numerical simulation of a turbulent channel flow with heat transfer was performed at very low Reynolds numbers. Two different thermal boundary conditions were studied, and temperature was considered as a passive scalar. The computations were carried out with huge computational boxes (up to 327.7 x 2 x 128 in the streamwise, wall-normal, and spanwise directions, respectively). The emphases of this paper are to investigate the large-scale structure (puff) in the intermittent-turbulent flow including the scalar fields and to provide the values of the transitional and critical Reynolds numbers, below which the turbulent flow becomes intermittent and laminar, respectively. The statistics, such as the skin friction and the Stanton number, were also examined: they suggest that the puff should be effective in sustaining turbulence and in heat transfer enhancement.

Tsukahara, Takahiro

2014-01-01T23:59:59.000Z

271

Group solution for unsteady free-convection flow from a vertical moving plate subjected to constant heat flux  

Science Journals Connector (OSTI)

The problem of heat and mass transfer in an unsteady free-convection flow over a continuous moving vertical sheet in an ambient fluid is investigated for constant heat flux using the group theoretical method. The nonlinear coupled partial differential ... Keywords: 22E05, 35Q53, 54H15, Free convective flow, Group theoretic method, Prandtl number, Thermal boundary layer

M. Kassem

2006-03-01T23:59:59.000Z

272

Study of junction flows in louvered fin round tube heat exchangers using the dye injection technique  

SciTech Connect (OSTI)

Detailed studies of junction flows in heat exchangers with an interrupted fin design are rare. However, understanding these flow structures is important for design and optimization purposes, because the thermal hydraulic performance of heat exchangers is strongly related to the flow behaviour. In this study flow visualization experiments were performed in six scaled-up models of a louvered fin round tube heat exchanger. The models have three tube rows in a staggered layout and differ only in their fin spacing and louver angle. A water tunnel was designed and built and the flow visualizations were carried out using dye injection. At low Reynolds numbers the streakline follows the tube contours, while at higher Reynolds numbers a horseshoe vortex is developed ahead of the tubes. The two resulting streamwise vortex legs are destroyed by the downstream louvers (i.e. downstream the turnaround louver), especially at higher Reynolds numbers, smaller fin pitches and larger louver angles. Increasing the fin spacing results in a larger and stronger horseshoe vortex. This illustrates that a reduction of the fin spacing results in a dissipation of vortical motion by mechanical blockage and skin friction. Furthermore it was observed that the vortex strength and number of vortices in the second tube row is larger than in the first tube row. This is due to the thicker boundary layer in the second tube row, and the flow deflection, which is typical for louvered fin heat exchangers. Visualizations at the tube-louver junction showed that in the transition part between the angled louver and the flat landing a vortex is present underneath the louver surface which propagates towards the angled louver. (author)

Huisseune, H.; Willockx, A.; De Paepe, M. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); T'Joen, C. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); Department Radiation, Radionuclides and Reactors, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); De Jaeger, P. [Department of Flow, Heat and Combustion Mechanics, Ghent University, Sint-Pietersnieuwstraat 41, 9000 Gent (Belgium); NV Bekaert SA, Bekaertstraat 2, 8550 Zwevegem (Belgium)

2010-11-15T23:59:59.000Z

273

High explosive violent reaction (HEVR) from slow heating conditions  

SciTech Connect (OSTI)

The high explosives (HEs) developed and used at the Los Alamos National Laboratory are designed to be insensitive to impact and thermal insults under all but the most extreme conditions. Nevertheless, violent reactions do occasionally occur when HE is involved in an accident. The HE response is closely dependent on the type of external stimulus that initiates the reaction. For example, fast heating of conventional HE will probably result in fairly benign burning, while long-term, slow heating of conventional HE is more likely to produce an HEVR that will do much more damage to the immediate surroundings. An HEVR (High Explosive Violent Reaction) can be defined as the rapid release of energy from an explosive that ranges from slightly faster than a deflagration (very rapid burning) to a reaction that approaches a detonation. A number of thermal analyses have been done to determine slow heat/cook-off conditions that produce HE self-heating that can build up to a catastrophic runaway reaction. The author specifies the conditions that control reaction violence, describes experiments that produced an HEVR, describes analyses done to determine a heating rate threshold for HEVR, and lists possible HEVR situations.

Vigil, A.S.

1999-03-01T23:59:59.000Z

274

EUROTHERM Seminar 74 Proceedings Heat transfer in unsteady and transitional flows March 23-26, 2003 Eindhoven (The Netherlands)  

E-Print Network [OSTI]

EUROTHERM Seminar 74 Proceedings Heat transfer in unsteady and transitional flows March 23-26, 2003 to be governed by heat transfer and time microscales of turbulence through the inner sublayer. Physical interpreta- tions are given to relate the observed heat transfer correlation and these turbulence transition

Paris-Sud XI, Université de

275

Exergy analysis of second-generation micro heat sinks under single-phase and flow boiling conditions  

Science Journals Connector (OSTI)

A parametric study of exergy efficiency was conducted for five micro pin fin heat sinks of different spacing and shapes. Of the four micro pin fin heat sinks tested under single-phase flow conditions, those with better heat transfer performance yielded superior exergy efficiencies. The use of R-123 in place of water as working fluid was found to enhance exergetic performance at the expense of reduced heat transfer performance. The exergy analysis was also extended to the flow boiling of R-123 in an additional hydrofoil-based micro pin fin heat sink. It was found that exergy efficiencies decreased with mass velocity.

Ali Kosar

2010-01-01T23:59:59.000Z

276

Anomalous High-Frequency Resistivity and Heating of a Plasma  

Science Journals Connector (OSTI)

Computer experiments have been carried out on the anomalous heating of a one-dimensional plasma by a large-amplitude long-wavelength electric field oscillating near the plasma frequency. Above a certain threshold the large driver field excites an instability in the plasma and drives up ion-density fluctuations as well as plasma oscillations. When the ion fluctuations reach a sufficiently large level, the plasma begins to heat very efficiently according to an anomalous resistivity. An effective collision frequency as high as 0.2?pe has been observed. A theoretical explanation of the observed results is given.

W. L. Kruer; P. K. Kaw; J. M. Dawson; C. Oberman

1970-05-04T23:59:59.000Z

277

The influence of convective heat transfer on flow stability in rotating disk chemical vapor deposition reactors  

SciTech Connect (OSTI)

Flow and heat transfer of NH{sub 3} and He were studied in a rotating disk system with applications to chemical vapor deposition reactors. Flow field and disk heat flux were obtained over a range of operating conditions. Comparisons of disk convective heat transfer were made to infinite rotating disk results to appraise uniformity of transport to the disk. Important operating variables include disk spin rate, disk and enclosure temperatures, flow rate, composition, pressure, and gas mixture temperature at the reactor inlet. These variables were studied over ranges of the spin Reynolds number, Re{omega}; disk mixed convection parameter, MCP{sub w}; and wall mixed convection parameter, MCP{sub w}. Results obtained for NH{sub 3} show that increasing Re{omega} from 314.5 to 3145 increases the uniformity of rotating disk heat flux and results in thinner thermal boundary layers at the disk surface. At Re{omega}=314.5, increasing MCP{sub d} to 15 leads to significant departure from the infinite disk result with nonuniform disk heat fluxes and recirculating flow patterns; flow becomes increasingly complex at larger values of MCP{sub d}. At Re{omega} of 3145, results are closer to the infinite disk for MCP{sub d} up to 15. For large negative (hot walls) and positive (cold walls) values of MCP{sub w}, flow recirculates and there is significant deviation from the infinite disk result; nonuniformities occur at both values of Re{omega}. The influence of MCP{sub w} on flow stability is increased at larger MCP{sub d} and lower Re{omega}. To determine the influence of viscosity and thermal conductivity variation with temperature, calculations were made with He and NH{sub 3}; He transport property variation is low relative to NH{sub 3}. Results show that the flow of NH{sub 3} is less stable than that of He as MCP{sub d} is increased for MCP{sub w}=0 and Re{omega}=314.5. 16 refs., 15 figs., 1 tab.

Winters, W.S.; Evans, G.H. [Sandia National Labs., Livermore, CA (United States); Grief, R. [Univ. of California, Berkeley, CA (United States). Mechanical Engineering Dept.

1997-06-01T23:59:59.000Z

278

Heat loss model for flow assurance in a deep water riser  

Science Journals Connector (OSTI)

The study is intended to investigate the heat loss phenomenon of oil flow in a riser. This heat loss happens due to the difference between the oil temperature in a riser and the surrounding sea water temperature. It causes the formation of wax that may disturb the flow. Heat loss can be reduced by setting up an insulator in a riser or by selecting appropriate pipeline specifications. It is necessary to determine the possible locations and specifications of insulator and pipeline. A mathematical model is formulated by considering the oil temperature and its flow velocity. Assuming that the density variation is small the fluid behaves as an incompressible fluid. Furthermore numerical solutions with finite difference methods are presented with some hypothetical data to give an overview of how the system works. Two surrounding conditions are taken into account i.e. with and without sea current. From the simulation the location of wax formation can be predicted. At a certain depth region of sea where the sea current is present a greater heat loss take place in which wax may be formed immediately. To overcome the formation of wax we can control the parameters such as conductivity and wall thickness of pipe.

Pudjo Sukarno

2014-01-01T23:59:59.000Z

279

Numerical investigation of electric heating impacts on solid/liquid glass flow patterns.  

SciTech Connect (OSTI)

A typical glass furnace consists of a combustion space and a melter. Intense heat is generated from the combustion of fuel and air/oxygen in the combustion space. This heat is transferred mainly by radiation to the melter in order to melt sand and cullet (scrap glass) eventually creating glass products. Many furnaces use electric boosters to enhance glass melting and increase productivity. The coupled electric/combustion heat transfer patterns are key to the glass making processes. The understanding of the processes can lead to the improvement of glass quality and furnace efficiency. The effects of electrical boosting on the flow patterns and heat transfer in a glass melter are investigated using a multiphase Computational Fluid Dynamics (CFD) code with addition of an electrical boosting model. The results indicate that the locations and spacing of the electrodes have large impacts on the velocity and temperature distributions in the glass melter. With the same total heat input, the batch shape (which is determined by the overall heat transfer and the batch melting rate) is kept almost the same. This indicates that electric boosting can be used to replace part of heat by combustion. Therefore, temperature is lower in the combustion space and the life of the furnace can be prolonged. The electric booster can also be used to increase productivity without increasing the furnace size.

Chang, S. L.; Zhou, C. Q.; Golchert, B.

2002-07-02T23:59:59.000Z

280

Remote high-temperature insulatorless heat-flux gauge  

DOE Patents [OSTI]

A remote optical heat-flux gauge for use in extremely high temperature environments is described. This application is possible because of the use of thermographic phosphors as the sensing media, and the omission of the need for an intervening layer of insulator between phosphor layers. The gauge has no electrical leads, but is interrogated with ultraviolet or laser light. The luminescence emitted by the two phosphor layers, which is indicative of the temperature of the layers, is collected and analyzed in order to determine the heat flux incident on the surface being investigated. The two layers of thermographic phosphor must be of different materials to assure that the spectral lines collected will be distinguishable. Spatial heat-flux measurements can be made by scanning the light across the surface of the gauge. 3 figures.

Noel, B.W.

1993-12-28T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Remote high-temperature insulatorless heat-flux gauge  

DOE Patents [OSTI]

A remote optical heat-flux gauge for use in extremely high temperature environments is described. This application is possible because of the use of thermographic phosphors as the sensing media, and the omission of the need for an intervening layer of insulator between phosphor layers. The gauge has no electrical leads, but is interrogated with ultraviolet or laser light. The luminescence emitted by the two phosphor layers, which is indicative of the temperature of the layers, is collected and analyzed in order to determine the heat flux incident on the surface being investigated. The two layers of thermographic phosphor must be of different materials to assure that the spectral lines collected will be distinguishable. Spatial heat-flux measurements can be made by scanning the light across the surface of the gauge.

Noel, Bruce W. (Espanola, NM)

1993-01-01T23:59:59.000Z

282

Predicting High Harmonic Ion Cyclotron Heating Efficiency in Tokamak Plasmas  

Science Journals Connector (OSTI)

Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (?kV?m-1) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

D. L. Green; L. A. Berry; G. Chen; P. M. Ryan; J. M. Canik; E. F. Jaeger

2011-09-26T23:59:59.000Z

283

RELAP5/MOD3 code quality assurance plan for ORNL ANS narrow channel flow and heat transfer correlations  

SciTech Connect (OSTI)

Modifications have been made to REIAP5 to account for flow and heat transfer in narrow channels between fuel plates such as found in the cores of the Advanced Neutron Source (ANS) and High Flux Isotope Reactor (HFIR) reactors. These early models were supplied by Art Ruggles of Oak Ridge National Laboratory (ORNL) and Don Fletcher of the Idaho National Engineering Laboratory (INEL) and were adapted to and implemented into RELAP5 by Rich Riemke, Rex Shumway and Ken Katsma. The purpose of this report is to document the current status of these special models in the standard version of RELAP5/MOD3 and describe the quality assurance procedures.

MIller, C.S.; Shumway, R.W.

1992-11-01T23:59:59.000Z

284

Influence of variable property effects on natural convection flows in asymmetrically-heated vertical channels  

SciTech Connect (OSTI)

The influence of variable property effects on the laminar air flow induced by natural convection in a vertical, asymmetrically-heated channel is investigated. A full-elliptic model that accounts for variations of viscosity and thermal conductivity with temperature and determines the density from the state equation, has been solved numerically for cases for which variable property effects are important, particularly for conditions for which flow reversals may appear. The corresponding numerical results are compared with those obtained from an alternative model in which all thermophysical properties are assumed to be constant and the Boussinesq approximation is used. It has been found that variable property effects have a strong influence, not reported in previous works, on the recirculation patterns, and may produce, for certain ranges of parameters that roughly coincide with those for which flow reversals exist, an increase in the mass flow rate induced in the channel.

Zamora, B. [Univ. de Murcia (Spain)] [Univ. de Murcia (Spain); Hernandez, J. [Ciudad Universitaria, Madrid (Spain)] [Ciudad Universitaria, Madrid (Spain)

1997-12-01T23:59:59.000Z

285

High-Temperature Components for Rankine-Cycle-Based Waste Heat...  

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

Components for Rankine-Cycle-Based Waste Heat Recovery Systems on Combustion Engines High-Temperature Components for Rankine-Cycle-Based Waste Heat Recovery Systems on...

286

Micro-canonical thermodynamics: Why does heat flow from hot to cold  

E-Print Network [OSTI]

We consider two weakly coupled Hamiltonian dynamical systems in the micro-canonical ensemble. We describe a stochastic model for the energy-transfer between two systems initially at different micro-canonical temperatures. Fluctuations in energy observables are shown to be the underlying source of heat-transfer (dissipation). As a result, on average, heat flows from hot to cold. Like in Evans et al. (Phys.\\ Rev.\\ Lett.) [71], 2401 (1993), we obtain a universal law of violation of the 2nd law of thermodynamics.

Rugh, Hans Henrik

2012-01-01T23:59:59.000Z

287

Numerical simulation of fluid flow and heat transfer inside a rotating disk-cylinder configuration by a lattice Boltzmann model  

Science Journals Connector (OSTI)

A simple lattice Boltzmann model for numerical simulation of fluid flow and heat transfer inside a rotating disk-cylinder configuration, which is of fundamental interest and practical importance in science as well as in engineering, is proposed in this paper. Unlike existing lattice Boltzmann models for such flows, which were based on “primitive-variable” Navier-Stokes equations, the target macroscopic equations of the present model for the flow field are vorticity–stream function equations, inspired by our recent work designed for nonrotating flows [S. Chen, J. Tölke, and M. Krafczyk, Phys. Rev. E 79, 016704 (2009); S. Chen, J. Tölke, S. Geller, and M. Krafczyk, Phys. Rev. E 78, 046703 (2008)]. The flow field and the temperature field both are solved by the D2Q5 model. Compared with the previous models, the present model is more efficient, more stable, and much simpler. It was found that, even though with a relatively low grid resolution, the present model can still work well when the Grashof number is very high. The advantages of the present model are validated by numerical experiments.

Sheng Chen; Jonas Tölke; Manfred Krafczyk

2009-07-14T23:59:59.000Z

288

High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, Cyclones and localized heating  

E-Print Network [OSTI]

High-power ELF radiation generated by modulated HF heating of the ionosphere can cause Earthquakes, the HAARP heater is the most powerful ionospheric heater, with 3.6GW of effective power using HF heating, Cyclones and localized heating Fran De Aquino Maranhao State University, Physics Department, S

Paris-Sud XI, Université de

289

Heat flow in the Coso geothermal area, Inyo County, California | Open  

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 » Heat flow in the Coso geothermal area, Inyo County, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Heat flow in the Coso geothermal area, Inyo County, California Details Activities (2) Areas (1) Regions (0) Abstract: Obvious surface manifestations of an anomalous concentration of geothermal resources at the Coso geothermal area, Inyo County, California, include fumarolic activity and associated hydrothermally altered rocks. Pleistocene volcanic rocks associated with the geothermal activity include 38 rhyolite domes occupying a north trending structural and topographic

290

Heat transfer enhancement on thin wires in superfluid helium forced flows  

E-Print Network [OSTI]

In this paper, we report the first evidence of an enhancement of the heat transfer from a heated wire by an external turbulent flow of superfluid helium. We used a standard Pt-Rh hot-wire anemometer and overheat it up to 21 K in a pressurized liquid helium turbulent round jet at temperatures between 1.9 K and 2.12 K. The null-velocity response of the sensor can be satisfactorily modeled by the counter flow mechanism while the extra cooling produced by the forced convection is found to scale similarly as the corresponding extra cooling in classical fluids. We propose a preliminary analysis of the response of the sensor and show that -contrary to a common assumption- such sensor can be used to probe local velocity in turbulent superfluid helium.

Duri, Davide; Moro, Jean-Paul; Roche, Philippe-Emmanuel; Diribarne, Pantxo

2014-01-01T23:59:59.000Z

291

Review of fluid flow and convective heat transfer within rotating disk cavities with impinging jet  

E-Print Network [OSTI]

Fluid flow and convective heat transfer in rotor-stator configurations, which are of great importance in different engineering applications, are treated in details in this review. The review focuses on convective heat transfer in predominantly outward air flow in the rotor-stator geometries with and without impinging jets and incorporates two main parts, namely, experimental/theoretical methodologies and geometries/results. Experimental methodologies include naphthalene sublimation techniques, steady state (thin layer) and transient (thermochromic liquid crystals) thermal measurements, thermocouples and infra-red cameras, hot-wire anemometry, laser Doppler and particle image velocimetry, laser plane and smoke generator. Theoretical approaches incorporate modern CFD computational tools (DNS, LES, RANS etc). Geometries and results part being mentioned starting from simple to complex elucidates cases of a free rotating disk, a single disk in the crossflow, single jets impinging onto stationary and rotating disk,...

Harmand, Souad; Poncet, Sébastien; Shevchuk, Igor V; 10.1016/j.ijthermalsci.2012.11.009

2013-01-01T23:59:59.000Z

292

Boundary layer flow and heat transfer analysis of a second-grade fluid  

SciTech Connect (OSTI)

Boundary layer flow and heat transfer analysis of a homogeneous, incompressible, non-Newtonian fluid of grade two at a stagnation point is presented. The flow is assumed to be steady and laminar. A power-law representation is assumed for the velocity distribution and wall temperature variation. The governing equations are solved using an iterative central difference approximation method in a non-uniform grid domain. This analysis show the effect of non-Newtonian nature of the fluid and the effect of suction/injection on the velocity profile. The effect of non-Newtonian nature of the fluid on the heat transfer coefficient at the wall for different values of Prandtl number and wall-temperature variation is also presented. (VC)

Massoudi, M. [USDOE Pittsburgh Energy Technology Center, PA (United States); Ramezan, M. [Burns and Roe Services Corp., Pittsburgh, PA (United States)

1992-04-01T23:59:59.000Z

293

A Cross-Flow Ceramic Heat Recuperator for Industrial Heat Recovery  

E-Print Network [OSTI]

recuperators currently available suffer from problems of creep, corrosion and oxidation, particularly at high temperatures. The Department of Energy and GTE Products corporation have pursued a jointly funded venture, Contract No. EX-76-C-Q1-2162, to establish...

Gonzalez, J. M.; Cleveland, J. J.; Kohnken, K. H.; Rebello, W. J.

1980-01-01T23:59:59.000Z

294

Project Profile: High Operating Temperature Liquid Metal Heat Transfer Fluids  

Broader source: Energy.gov [DOE]

The University of California, Los Angeles (UCLA), along with partners at the University of California, Berkeley, and Yale University, under the 2012 Multidisciplinary University Research Initiative (MURI): High Operating Temperature (HOT) Fluids funding opportunity, is investigating the use of metal alloys as a heat transfer fluid (HTF) in concentrating solar power (CSP) systems operating at temperatures in excess of 800°C. By allowing higher temperature operation, CSP systems can achieve greater efficiencies and thereby reduce the overall cost of electricity production.

295

Heat extracted from the long term flow test in the Fenton Hill HDR reservoir  

SciTech Connect (OSTI)

A long-term flow test was carried out in the Fenton Hill HDR Phase-2 reservoir for 14 months during 1992-1993 to examine the potential for supplying thermal energy at a sustained rate as a commercial demonstration of HDR technology. The test was accomplished in several segments with changes in mean flowrate due to pumping conditions. Re-test estimates of the extractable heat content above a minimum useful temperature were based on physical evidence of the size of the Fenton Hill reservoir. A numerical model was used to estimate the extent of heat extracted during the individual flow segments from the database of measured production data during the test. For a reservoir volume of 6.5x10{sup 6}m{sup 3}, the total heat content above a minimum temperature of 150{degree} C was 1.5x10{sup 15}J. For the total test period at the three sustained mean flowrates, the integrated heat extracted was 0.088x10{sup 15}J, with no discernable temperature decline of the produced fluid. The fraction of energy extracted above the abandonment temperature was 5.9%. On the basis of a constant thermal energy extraction rate, the lifetime of the reservoir (without reservoir growth) to the abandonment temperature would be 13.3 years, in good agreement with the pre-test estimate of 15.0 years for the given reservoir volume.

Kruger, Paul; Robinson, Bruce

1994-01-20T23:59:59.000Z

296

Ultra high vacuum heating and rotating specimen stage  

DOE Patents [OSTI]

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1.times.10.sup.-9 torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating.

Coombs, III, Arthur W. (Patterson, CA)

1995-01-01T23:59:59.000Z

297

Ultra high vacuum heating and rotating specimen stage  

DOE Patents [OSTI]

A heating and rotating specimen stage provides for simultaneous specimen heating and rotating. The stage is ideally suited for operation in ultrahigh vacuum (1{times}10{sup {minus}9} torr or less), but is useful at atmosphere and in pressurized systems as well. A specimen is placed on a specimen holder that is attached to a heater that, in turn, is attached to a top housing. The top housing is rotated relative to a bottom housing and electrically connected thereto by electrically conductive brushes. This stage is made of materials that are compatible with UHV, able to withstand high temperatures, possess low outgassing rates, are gall and seize resistant, and are able to carry substantial electrical loading without overheating. 5 figs.

Coombs, A.W. III

1995-05-02T23:59:59.000Z

298

Secondary heat exchanger design and comparison for advanced high temperature reactor  

SciTech Connect (OSTI)

Next generation nuclear reactors such as the advanced high temperature reactor (AHTR) are designed to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. This study considers two different types of heat exchangers - helical coiled heat exchanger and printed circuit heat exchanger - as possible options for the AHTR secondary heat exchangers with distributed load analysis and comparison. Comparison is provided for all different cases along with challenges and recommendations. (authors)

Sabharwall, P. [Idaho National Laboratory, Idaho Falls, ID 83415-3860 (United States); Kim, E. S. [Seoul National Univ., P.O. Box 1625, Idaho Falls, ID 83415-3860 (United States); Siahpush, A.; McKellar, M.; Patterson, M. [Idaho National Laboratory, Idaho Falls, ID 83415-3860 (United States)

2012-07-01T23:59:59.000Z

299

Flow and heat transfer from a continuous surface in a parallel free stream of viscoelastic second-order fluid  

Science Journals Connector (OSTI)

Boundary layer solutions are presented to investigate the steady flow and heat transfer characteristics from a continuous flat surface moving in a parallel free stream of viscoelastic fluid. Numerical results are...

I. A. Hassanien

1992-10-01T23:59:59.000Z

300

FRAC-STIM: A Physics-Based Fracture Simulation, /reservoir Flow and Heat Transport Simulator(aka FALCON)  

Broader source: Energy.gov [DOE]

FRAC-STIM: A Physics-Based Fracture Simulation, /reservoir Flow and Heat Transport Simulator(aka FALCON) presentation at the April 2013 peer review meeting held in Denver, Colorado.

Note: This page contains sample records for the topic "high heat flow" 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

Electron Heating by the Ion Cyclotron Instability in Collisionless Accretion Flows. II. Electron Heating Efficiency as a Function of Flow Conditions  

E-Print Network [OSTI]

In the innermost regions of low-luminosity accretion flows, including Sgr A* at the center of our Galaxy, the frequency of Coulomb collisions is so low that the plasma is two-temperature, with the ions substantially hotter than the electrons. This paradigm assumes that Coulomb collisions are the only channel for transferring the ion energy to the electrons. In this work, the second of a series, we assess the efficiency of electron heating by ion velocity-space instabilities in collisionless accretion flows. The instabilities are seeded by the pressure anisotropy induced by magnetic field amplification, coupled to the adiabatic invariance of the particle magnetic moments. Using two-dimensional (2D) particle-in-cell (PIC) simulations, we showed in Paper I that if the electron-to-ion temperature ratio is cyclotron instability is the dominant mode for values of ion beta_i ~ 5-30 (here, beta_i is the ratio of ion thermal pressure to magnetic pressure), as appropriate for the midplane of low-lumin...

Sironi, Lorenzo

2014-01-01T23:59:59.000Z

302

High energy density redox flow device  

DOE Patents [OSTI]

Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

Chiang, Yet-Ming; Carter, William Craig; Duduta, Mihai; Limthongkul, Pimpa

2014-05-13T23:59:59.000Z

303

Cross-Roll Flow Forming of ODS Alloy Heat Exchanger Tubes for Hoop Creep Enhancement  

SciTech Connect (OSTI)

Mechanically alloyed oxide dispersion strengthened (ODS) Fe-Cr-Al alloy thin walled tubes and sheets, produced via powder processing and consolidation methodologies, are promising materials for eventual use at temperatures up to 1200 C in the power generation industry, far above the temperature capabilities of conventional alloys. Target end-uses range from gas turbine combustor liners to high aspect ratio (L/D) heat exchanger tubes. Grain boundary creep processes at service temperatures, particularly those acting in the hoop direction, are the dominant failure mechanisms for such components. The processed microstructure of ODS alloys consists of high aspect ratio grains aligned parallel to the tube axis, a result of dominant axial metal flow which aligns the dispersoid particles and other impurities in the longitudinal direction. The dispersion distribution is unaltered on a micro scale by recrystallization thermal treatments, but the high aspect ratio grain shape typically obtained limits transverse grain spacing and consequently the hoop creep response. Improving hoop creep in ODS-alloy components will require understanding and manipulating the factors that control the recrystallization behavior, and represents a critical materials design and development challenge that must be overcome in order to fully exploit the potential of ODS alloys. The objectives of this program are to (1) increase creep-strength at temperature in ODS-alloy tube and liner components by 100% via, (2) preferential cross-roll flow forming and grain/particle fibering in the critical hoop direction. The research program outlined here is iterative in nature and is intended to systematically (1) examine and identify post-extrusion forming methodologies to create hoop strengthened tubes, which will be (2) evaluated at ''in-service'' loads at service temperatures and environments. This research program is being conducted in collaboration with the DOE's Oak Ridge National Laboratory and the vested industrial partner Special Metals Corporation. In this ninth quarter of performance, program activities are continued for Tasks 2, 3 and 4 and are reported herein. Two sets of MA956 tube material samples rotary crossrolled at rolling angles of {beta} = 2{sup o} and 8{sup o} are processed in Task 3 and available for mechanical property testing in the remainder of this project. These samples are at various stages of creep testing and evaluation in Task 4. The creep rigs are being upgraded to handle long term testing at 1000 C and above. Reduced test times at accelerated temperatures will allow for additional testes to be conducted resulting in overall robust creep data statistics. The creep performance enhancement in cross-rolled MA956 material samples versus the base creep property is elucidated. Additional creep enhancements are derived when flow formed tubes are flattened at 900 C and recrystallized. The Larsen-Miller parameter for the improvised thermo-mechanical processing now approaches 52. At least 2-3 orders of magnitude of improvement in creep rates/day are demonstrated for the cross-rolled samples versus the base reference tests.

Bimal K. Kad

2006-04-10T23:59:59.000Z

304

Convective heat transfer enhancement of laminar flow of latent functionally thermal fluid in a circular tube with constant heat flux: internal heat source model and its application  

Science Journals Connector (OSTI)

This paper analyzes the convective heat transfer enhancement mechanism of latent heat functionally thermal fluid. By using the proposed internal heat source model, the influence of each factor affecting the heat

Yinping Zhang; Xianxu Hu; Qing Hao; Xin Wang

2003-04-01T23:59:59.000Z

305

Thermal hydraulic performance testing of printed circuit heat exchangers in a high-temperature helium test facility  

SciTech Connect (OSTI)

In high-temperature gas-cooled reactors, such as a very high temperature reactor (VHTR), an intermediate heat exchanger (IHX) is required to efficiently transfer the core thermal output to a secondary fluid for electricity generation with an indirect power cycle and/or process heat applications. Currently, there is no proven high-temperature (750–800 °C or higher) compact heat exchanger technology for high-temperature reactor design concepts. In this study, printed circuit heat exchanger (PCHE), a potential IHX concept for high-temperature applications, has been investigated for their heat transfer and pressure drop characteristics under high operating temperatures and pressures. Two PCHEs, each having 10 hot and 10 cold plates with 12 channels (semicircular cross-section) in each plate are fabricated using Alloy 617 plates and tested for their performance in a high-temperature helium test facility (HTHF). The PCHE inlet temperature and pressure were varied from 85 to 390 °C/1.0–2.7 MPa for the cold side and 208–790 °C/1.0–2.7 MPa for the hot side, respectively, while the mass flow rate of helium was varied from 15 to 49 kg/h. This range of mass flow rates corresponds to PCHE channel Reynolds numbers of 950 to 4100 for the cold side and 900 to 3900 for the hot side (corresponding to the laminar and laminar-to-turbulent transition flow regimes). The obtained experimental data have been analyzed for the pressure drop and heat transfer characteristics of the heat transfer surface of the PCHEs and compared with the available models and correlations in the literature. In addition, a numerical treatment of hydrodynamically developing and hydrodynamically fully-developed laminar flow through a semicircular duct is presented. Relations developed for determining the hydrodynamic entrance length in a semicircular duct and the friction factor (or pressure drop) in the hydrodynamic entry length region for laminar flow through a semicircular duct are given. Various hydrodynamic entrance region parameters, such as incremental pressure drop number, apparent Fanning friction factor, and hydrodynamic entrance length in a semicircular duct have been numerically estimated.

Sai K. Mylavarapu; Xiaodong Sun; Richard E. Glosup; Richard N. Christensen; Michael W. Patterson

2014-04-01T23:59:59.000Z

306

A parametric study of shock jump chemistry, electron temperature, and radiative heat transfer models in hypersonic flows  

E-Print Network [OSTI]

A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN GREENDYKE Submitted to the Graduate College of Texas A&M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1988 Major Subject: Aerospace Engineering A PARAMETRIC STUDY OF SHOCK JUMP CHEMISTRY, ELECTRON TEMPERATURE, AND RADIATIVE HEAT TRANSFER MODELS IN HYPERSONIC FLOWS A Thesis by ROBERT BRIAN...

Greendyke, Robert Brian

2012-06-07T23:59:59.000Z

307

Compare Energy Use in Variable Refrigerant Flow Heat Pumps Field Demonstration and Computer Model  

SciTech Connect (OSTI)

Variable Refrigerant Flow (VRF) heat pumps are often regarded as energy efficient air-conditioning systems which offer electricity savings as well as reduction in peak electric demand while providing improved individual zone setpoint control. One of the key advantages of VRF systems is minimal duct losses which provide significant reduction in energy use and duct space. However, there is limited data available to show their actual performance in the field. Since VRF systems are increasingly gaining market share in the US, it is highly desirable to have more actual field performance data of these systems. An effort was made in this direction to monitor VRF system performance over an extended period of time in a US national lab test facility. Due to increasing demand by the energy modeling community, an empirical model to simulate VRF systems was implemented in the building simulation program EnergyPlus. This paper presents the comparison of energy consumption as measured in the national lab and as predicted by the program. For increased accuracy in the comparison, a customized weather file was created by using measured outdoor temperature and relative humidity at the test facility. Other inputs to the model included building construction, VRF system model based on lab measured performance, occupancy of the building, lighting/plug loads, and thermostat set-points etc. Infiltration model inputs were adjusted in the beginning to tune the computer model and then subsequent field measurements were compared to the simulation results. Differences between the computer model results and actual field measurements are discussed. The computer generated VRF performance closely resembled the field measurements.

Sharma, Chandan; Raustad, Richard

2013-06-01T23:59:59.000Z

308

Numerical Evaluation of Flow and Heat Transfer in Plate-Pin Fin Heat Sinks with Various Pin Cross-Sections  

E-Print Network [OSTI]

in Table 3. The grid systems for all heat sink models areregion. The grid system for one of the heat sinks is shown

Zhou, Feng; Catton, Ivan

2011-01-01T23:59:59.000Z

309

Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas  

SciTech Connect (OSTI)

Observations of improved radio frequency (RF) heating efficiency in high-confinement (H-) mode plasmas on the National Spherical Tokamak Experiment (NSTX) are investigated by whole-device linear simulation. We present the first full-wave simulation to couple kinetic physics of the well confined core plasma to the poorly confined scrape-off plasma. The new simulation is used to scan the launched fast-wave spectrum and examine the steady-state electric wave field structure for experimental scenarios corresponding to both reduced, and improved RF heating efficiency. We find that launching toroidal wave-numbers that required for fast-wave propagation excites large amplitude (kVm 1 ) coaxial standing modes in the wave electric field between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggest these modes are a probable cause of degraded heating efficiency. Also, the H-mode density pedestal and fast-wave cutoff within the confined plasma allow for the excitation of whispering gallery type eigenmodes localised to the plasma edge.

Green, David L [ORNL; Jaeger, E. F. [XCEL; Berry, Lee A [ORNL; Chen, Guangye [ORNL; Ryan, Philip Michael [ORNL; Canik, John [ORNL

2011-01-01T23:59:59.000Z

310

High Magnetic Field Processing - A Heat-Free Heat Treating Method  

SciTech Connect (OSTI)

The High and Thermal Magnetic Processing/Electro-magnetic Acoustic Transducer (HTMP/EMAT) technology has been shown to be an enabling disruptive materials processing technology, that can achieve significant improvements in microstructure and consequently material performance beyond that achievable through conventional processing, and will lead to the next generation of advanced performance structural and functional materials. HTMP exposure increased the reaction kinetics enabling refinement of microstructural features such as finer martensite lath size, and finer, more copious, homogeneous dispersions of strengthening carbides leading to combined strength and toughness improvements in bainitic steels. When induction heating is applied in a high magnetic field environment, the induction heating coil is configured so that high intensity acoustic/ultrasonic treatment occurs naturally. The configuration results in a highly effective electromagnetic acoustical transducer (EMAT). HTMP combined with applying high-field EMAT, produce a non-contact ultrasonic treatment that can be used to process metal alloys in either the liquid state resulting in significant microstructural changes over conventional processing. Proof-of-principle experiments on cast irons resulted in homogeneous microstructures in small castings along with improved casting surface appearance. The experiment showed that by exposing liquid metal to the non-contact acoustic/ultrasonic processing technology developed using HMFP/EMAT wrought-like microstructures were developed in cast components. This Energy Intensive Processes (EIP) project sponsored by the DOE EERE Advanced Manufacturing Office (AMO) demonstrated the following: (1) The reduction of retained austenite in high carbon/high alloy steels with an ambient temperature HTMP process, replacing either a cryogenic or double tempering thermal process normally employed to accomplish retained austenite transformation. HTMP can be described as a 'heat-free', heat treating technology. Lower residual stresses in HTMP treated materials are anticipated since no thermal strains are involved in inducing the transformation of retained austenite to martensite in high alloy steel. (2) The simultaneous increase of 12% in yield strength and 22% in impact energy in a bainitic alloy using HTMP processing. This is a major breakthrough in materials processing for the next generation of structural materials since conventionally processed materials show a reduction in impact toughness with an increase in yield strength. HTMP is a new paradigm to beneficially increase both yield strength and impact energy absorption simultaneously. (3) HTMP processing refined both the martensite lath population and the carbide dispersion in a bainitic steel alloy during Gausstempering. The refinement was believed to be responsible for the simultaneous increase in strength and toughness. Hence, HTMP significantly impacts nucleation and growth phenomenon. (4) HTMP processing developed comparable ultimate tensile strength and twice the impact energy in a lower cost, lower alloy content ({approx}8% alloy content) steel, compared to highly alloyed, (31% alloy elements involving Ni, Co, and Mo) 250-grade margining steel. Future low-cost HTMP alloys appear viable that will exceed the structural performance of highly alloyed materials that are conventionally processed. This economic benefit will enable U.S. industry to reduce cost (better more competitive worldwide) while maintaining or exceeding current performance. (5) EMAT processed cast iron exhibits significantly higher hardness (by 51% for a 9T condition) than a no-field processed sample. (6) EMAT produced microstructures in cast iron resulted in an unique graphite nodule morphology, a modified pearlite content, and unique carbide types, that formed during solidification and cooling. (7) EMAT processed nanoparticle dispersions in Mg resulted in a very fine, unagglomerated distribution of the nanoparticles in the magnesium matrix. This provides a breakthrough technology to make the next generation of

Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Wilgen, John B [ORNL; Kenik, Edward A [ORNL; Parish, Chad M [ORNL; Rios, Orlando [ORNL; Rogers, Hiram [ORNL; Manuel, Michele [University of Florida, Gainesville; Kisner, Roger A [ORNL; Watkins, Thomas R [ORNL; Murphy, Bart L [ORNL

2012-08-01T23:59:59.000Z

311

The flow and heat transfer characteristics of multi-thermal fluid in horizontal wellbore coupled with flow in heavy oil reservoirs  

Science Journals Connector (OSTI)

Abstract As a new improved oil-recovery technique, multi-thermal fluid injection technology through a horizontal well has been widely used in the development process of heavy oil reservoirs. The flow and heat transfer characteristic of multi-thermal fluid in horizontal wellbore is significantly important for the productivity evaluation and parameters design of the horizontal well. Considering the specific physical properties of multi-thermal fluid, fluid absorption in perforation holes and pressure drop characteristics along the horizontal wellbore, this paper developed the flow and heat transfer model of multi-thermal fluid in perforated horizontal wellbore. In order to evaluate the heating effect of the multi-thermal fluid, a concept of effective heating length of a horizontal well is proposed. Then, a sensitivity analysis process is performed to study the influence of reservoir/fluid parameters and operating parameters on the flowing process of multi-thermal fluid in horizontal wellbore. Simultaneously, using the method of orthogonal numerical test, differential analysis and variance analysis are also conducted. Results show that the flowing process of multi-thermal fluid in horizontal wellbore includes a single-phase flowing process and a gas–liquid two-phase flowing process. The influence of oil viscosity on the flow and heat transfer characteristics of multi-thermal fluid in horizontal wellbore is most significant. Thereafter, the solution of our semi-analytical model is compared against the test results of an actual horizontal well from an oilfield in China. It is shown that the model results are in good agreement with the real test results. This model could be used to calculate and predict the flow and heat transfer characteristics of multi-thermal fluid (or saturated steam) in a perforated horizontal wellbore.

Xiaohu Dong; Huiqing Liu; Zhaoxiang Zhang; Changjiu Wang

2014-01-01T23:59:59.000Z

312

High Operating Temperature Liquid Metal Heat Transfer Fluids  

Broader source: Energy.gov [DOE]

This fact sheet describes a UCLA-led solar project to investigate high operating temperature liquid metal heat transfer fluids, funded by the SunShot initiative. The project team is using a combination of modeling along with a variety of property measurement and validation studies to demonstrate that the metal alloys identified can meet all the needs of a concentrating solar power plant. A successful candidate fluid would allow for the reduction of the levelized cost of energy by increasing the operating temperature for the CSP plant power cycle, which would increase thermal-to-electric conversion efficiency.

313

P~!ETRIC STUDY OF HEAT FLOW DURING RESISTANCE SPOT WELDING Euiwhan Kim and Thomas W. Eagar  

E-Print Network [OSTI]

pieces , electrical contact resistance, material properties, phase changes and heat dissipationi ...) P~!ETRIC STUDY OF HEAT FLOW DURING RESISTANCE SPOT WELDING Euiwhan Kim and Thomas W. Eagar Department of Materials Science and Engineering Hassachusetts Institute of Technology Cambridge, MA 02139

Eagar, Thomas W.

314

Low and high Temperature Dual Thermoelectric Generation Waste Heat Recovery System for Light-Duty Vehicles  

Broader source: Energy.gov [DOE]

Developing a low and high temperature dual thermoelectric generation waste heat recovery system for light-duty vehicles.

315

Micro-canonical thermodynamics: Why does heat flow from hot to cold  

E-Print Network [OSTI]

We show how to use a central limit approximation for additive co-cycles to describe non-equilibrium and far from equilibrium thermodynamic behavior. We consider first two weakly coupled Hamiltonian dynamical systems initially at different micro-canonical temperatures. We describe a stochastic model where the energy-transfer between the two systems is considered as a random variable satisfying a central limit approximation. We show that fluctuations in energy observables are linearly related to the heat-transfer (dissipation). As a result, on average, heat flows from hot to cold. We also consider the far from equilibrium situation of a non-Hamiltonian thermostatted system as in Evans et al. {\\em Phys.\\ Rev.\\ Lett.} {\\bf 71}, 2401 (1993). Applying the same central limit approximation we re-derive their relation for the violation of the 2nd law of thermodynamics. We note that time-reversal symmetry is not used in our derivation.

Hans Henrik Rugh

2012-04-10T23:59:59.000Z

316

High-Energy Shock Waves Induce Blood Flow Reduction in Tumors  

Science Journals Connector (OSTI)

...Experimental Therapeutics High-Energy Shock Waves Induce Blood Flow Reduction...extracorporeally applied high-energy shock waves (HESW) on blood flow in amelanotic...therapeutical modalities. High-energy shock waves induce blood flow reduction...

Fernando Gamarra; Fritz Spelsberg; Gerhard E. H. Kuhnle; and Alwin E. Goetz

1993-04-01T23:59:59.000Z

317

On the calculation of flow and heat transfer characteristics for CANDU-type 19-rod fuel bundles  

SciTech Connect (OSTI)

A numerical study is reported of flow and heat transfer in a CANDU-type 19 rod fuel bundle. The flow domain of interest includes combinations of trangular, square, and peripheral subchannels. The basic equations of momentum and energy are solved with the standard k--epsilon model of turbulence. Isotropic turbulent viscosity is assumed and no secondary flow is considered for this steady-state, fully developed flow. Detailed velocity and temperature distributions with wall shear stress and Nusselt number distributions are obtained for turbulent flow of Re = 4.35 x 10/sup 4/, 10/sup 5/, 2 x 10/sup 5/, and for laminar flow of Re--2400. Friction factor and heat transfer ceofficients of various subchannels inside the full bundle are compared with those of infinite rod arrays of triangular or square arrangements. The calculated velocity contours of peripheral subchannel agreed reasonably with measured data.

Yuh-Shan Yueh; Ching-Chang Chieng

1987-08-01T23:59:59.000Z

318

On the calculation of flow and heat transfer characteristics for CANDU-type 19-rod fuel bundles  

SciTech Connect (OSTI)

A numerical study is reported of flow and heat transfer in a CANDU-type 19 rod fuel bundle. The flow domain of interest includes combinations of triangular, square, and peripheral subchannels. The basic equations of momentum and energy are solved with the standard k-{epsilon} model of turbulence. Isotropic turbulent viscosity is assumed and no secondary flow is considered for this steady-state, fully developed flow. Detailed velocity and temperature distributions with wall shear stress and Nusselt number distributions are obtained for turbulent flow of Re = 4.35 {times} 10{sup 4}, 10{sup 5}, 2 {times} 10{sup 5}, and for laminar flow of Re {approximately} 2,400. Friction factor and heat transfer coefficients of various subchannels inside the full bundle are compared with those of infinite rod arrays of triangular or square arrangements. The calculated velocity contours of peripheral subchannel agreed reasonably with measured data.

Yueh, Yuhshan; Chieng, Chingchang (National Tsing Hua Univ., Hsinchu (Taiwan))

1987-08-01T23:59:59.000Z

319

On numerical simulation of flow, heat transfer and combustion processes in tangentially-fired furnace  

SciTech Connect (OSTI)

In this work, an Eulerian/Lagrangian approach has been employed to investigate numerically flow characteristics, heat transfer and combustion processes inside corner-fired power plant boiler furnace. To avoid pseudo-diffusion that is significant in modeling tangentially-fired furnaces, some attempts have been made at improving the finite-difference scheme. Comparisons have been made between standard {kappa}-{epsilon} model and RNG {kappa}-{epsilon} model. Some new developments on turbulent diffusion of particles are taken into account in an attempt to improve computational accuracy. Finally, temperature deviation is studied numerically so as to gain deeper insight into tangentially fired furnace.

Sun, P.; Fan, J.; Cen, K.

1999-07-01T23:59:59.000Z

320

Secondary Heat Exchanger Design and Comparison for Advanced High Temperature Reactor  

SciTech Connect (OSTI)

The goals of next generation nuclear reactors, such as the high temperature gas-cooled reactor and advance high temperature reactor (AHTR), are to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. The need for efficiency, compactness, and safety challenge the boundaries of existing heat exchanger technology, giving rise to the following study. Various studies have been performed in attempts to update the secondary heat exchanger that is downstream of the primary heat exchanger, mostly because its performance is strongly tied to the ability to employ more efficient conversion cycles, such as the Rankine super critical and subcritical cycles. This study considers two different types of heat exchangers—helical coiled heat exchanger and printed circuit heat exchanger—as possible options for the AHTR secondary heat exchangers with the following three different options: (1) A single heat exchanger transfers all the heat (3,400 MW(t)) from the intermediate heat transfer loop to the power conversion system or process plants; (2) Two heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants, each exchanger transfers 1,700 MW(t) with a parallel configuration; and (3) Three heat exchangers share heat to transfer total heat of 3,400 MW(t) from the intermediate heat transfer loop to the power conversion system or process plants. Each heat exchanger transfers 1,130 MW(t) with a parallel configuration. A preliminary cost comparison will be provided for all different cases along with challenges and recommendations.

Piyush Sabharwall; Ali Siahpush; Michael McKellar; Michael Patterson; Eung Soo Kim

2012-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Transient Heat and Material Flow Modeling of Friction Stir Processing of Magnesium Alloy using Threaded Tool  

SciTech Connect (OSTI)

A three-dimensional transient computational fluid dynamics (CFD) model was developed to investigate the material flow and heat transfer during friction stir processing (FSP) in an AZ31B magnesium alloy. The material was assumed to be a non-Newtonian viscoplastic fluid, and the Zener-Hollomon parameter was used to describe the dependence of material viscosity on temperature and strain rate. The material constants used in the constitutive equation were determined experimentally from compression tests of the AZ31B Mg alloy under a wide range of strain rates and temperatures. A dynamic mesh method, combining both Lagrangian and Eulerian formulations, was used to capture the material flow induced by the movement of the threaded tool pin. Massless inert particles were embedded in the simulation domain to track the detailed history of material flow. The actual FSP was also carried out on a wrought Mg plate where temperature profiles were recorded by embedding thermocouples. The predicted transient temperature history was found to be consistent with that measured during FSP. Finally, the influence of the thread on the simulated results of thermal history and material flow was studied by comparing two models: one with threaded pin and the other with smooth pin surface.

Yu, Zhenzhen [ORNL; Zhang, Wei [ORNL; Choo, Hahn [ORNL; Feng, Zhili [ORNL

2012-01-01T23:59:59.000Z

322

SunShot Initiative: High Operating Temperature Liquid Metal Heat Transfer  

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

323

Fluid-to-fluid scaling for convective heat transfer in tubes at supercritical and high subcritical pressures  

Science Journals Connector (OSTI)

Abstract Following a review of two recent sets of fluid-to-fluid scaling laws for supercritical heat transfer and a discussion of their possible limitations, we have proposed two additional sets of scaling laws, which take into account empirically adjustable versions of the Dittus–Boelter correlation and which are applicable to both the supercritical and the high subcritical flow regions. We have compiled a database of heat transfer measurements in carbon dioxide flowing upwards in vertical heated tubes that are free of deterioration or enhancement. We then applied the four sets of scaling laws to these data to compute values of the water-equivalent heat transfer coefficient and compared these values to predictions of a transcritical look-up table, which was earlier shown to represent well a large compilation of measurements in water at supercritical and high subcritical pressures. It was shown that the two earlier methods systematically overestimated the heat transfer coefficient in water and also introduced significant imprecision. In contrast, the two proposed methods of scaling introduce no bias and have lower precision uncertainties than those of the previous scaling methods.

H. Zahlan; D.C. Groeneveld; S. Tavoularis

2014-01-01T23:59:59.000Z

324

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

325

On the dynamical Rayleigh-Taylor instability in compressible viscous flows without heat conductivity  

E-Print Network [OSTI]

We investigate the instability of a smooth Rayleigh-Taylor steady-state solution to compressible viscous flows without heat conductivity in the presence of a uniform gravitational field in a bounded domain $\\Omega\\subset{\\mathbb R}^3$ with smooth boundary $\\partial\\Omega$. We show that the steady-state is linearly unstable by constructing a suitable energy functional and exploiting arguments of the modified variational method. Then, based on the constructed linearly unstable solutions and a local well-posedness result of classical solutions to the original nonlinear problem, we further reconstruct the initial data of linearly unstable solutions to be the one of the original nonlinear problem and establish an appropriate energy estimate of Gronwall-type. With the help of the established energy estimate, we show that the steady-state is nonlinearly unstable in the sense of Hadamard by a careful bootstrap argument. As a byproduct of our analysis, we find that the compressibility has no stabilizing effect in the linearized problem for compressible viscous flows without heat conductivity.

Fei Jiang; Song Jiang

2014-03-20T23:59:59.000Z

326

3D numerical simulation on fluid flow and heat transfer characteristics in multistage heat exchanger with slit fins  

Science Journals Connector (OSTI)

In this paper, a numerical investigation is performed for three-stage heat exchangers with plain plate fins and slit ... are arranged in a staggered way, and heat conduction in fins is considered. In order ... av...

W. Q. Tao; Y. P. Cheng; T. S. Lee

2007-11-01T23:59:59.000Z

327

High Performance Catalytic Heat Exchanger for SOFC Systems - FuelCell Energy  

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

Catalytic Heat Catalytic Heat Exchanger for SOFC Systems-FuelCell Energy Background In a typical solid oxide fuel cell (SOFC) power generation system, hot (~900 °C) effluent gas from a catalytic combustor serves as the heat source within a high-temperature heat exchanger, preheating incoming fresh air for the SOFC's cathode. The catalytic combustor and the cathode air heat exchanger together represent the largest opportunity for cost

328

On the multidimensional modeling of fluid flow and heat transfer in SCWRS  

SciTech Connect (OSTI)

The Supercritical Water Reactor (SCWR) has been proposed as one of the six Generation IV reactor design concepts under consideration. The key feature of the SCWR is that water at supercritical pressures is used as the reactor coolant. Although at such pressures, fluids do not undergo phase change as they are heated, the fluid properties experience dramatic variations throughout what is known as the pseudo-critical region. Highly nonuniform temperature and fluid property distributions are expected in the reactor core, which will have a significant impact on turbulence and heat transfer in future SCWRs. The goal of the present work has been to understand and predict the effects of these fluid property variations on turbulence and heat transfer throughout the reactor core. Spline-type property models have been formulated for water at supercritical pressures in order to include the dependence of properties on both temperature and pressure into a numerical solver. New models of turbulence and heat transfer for variable-property fluids have been developed and implemented into the NPHASE-CMFD software. The results for these models have been compared to experimental data from the Korea Atomic Energy Research Inst. (KAERI) for various heat transfer regimes. It is found that the Low-Reynolds {kappa}-{epsilon} model performs best at predicting the experimental data. (authors)

Gallaway, T.; Antal, S. P.; Podowski, M. Z. [Center for Multiphase Research, Rensselaer Polytechnic Inst., 110 8th St., Troy, NY (United States)

2012-07-01T23:59:59.000Z

329

High-Performance Commercial Cold Climate Heat Pump | Department...  

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

cold climate commercial heat pump system. The system improves on state-of-the-art heat pumps, which can degrade by up to 60% in capacity and 50% in system coefficient of...

330

Development of high-temperature heat exchanger for hydrogen combustion turbine system  

SciTech Connect (OSTI)

New Rankine Cycle and Topping Regenerative Cycle are representative 500MW power generation systems for a hydrogen combustion turbine (HCT). The energy efficiency based on HHV of these is expected to be over 60% because the inlet temperature of turbine can be increased to 1,970K. These systems comprise various heat exchangers. Especially, the development of high temperature heat exchanger dealing with the high temperature and pressure steam is very important to realize the hydrogen combustion turbine system. The high-temperature heat exchanger of New Rankine Cycle is a supercritical heat recovery steam generator operating at pressure of 36MPa. This heat exchanger is heated by steam at temperature of 1,390K. On the other hand, Topping Regenerative Cycle has two high-temperature heat exchangers. One is a regenerator operating at pressure of 37MPa. The other is a regenerator operating at pressure of 5MPa. Both regenerators are heated by steam at temperature of 1,030K. The following are the principal development subject of high-temperature heat exchanger: (1) Improving the heat transfer characteristics to achieve the compact heat exchanger, and (2) Planning the heat exchanger structure suitable for the high thermal stress. To improve a heat transfer characteristic of the high-temperature heat exchangers, a parameter survey is conducted to optimize a tube arrangement and a fin configuration on tube outside and/or inside. The heat transfer areas are minimized through using the tubes with an extended heat transfer surface on both sides of a tube. Structural integrity is also estimated by conducting a structural analysis for the critical parts of the high-temperature heat exchangers.

Takakuwa, Akihiro; Mochida, Yoshio

1999-07-01T23:59:59.000Z

331

High Fidelity Simulation of Complex Suspension Flow for Practical Rheometry  

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

A visualization of the flow of concrete, a complex suspension A visualization of the flow of concrete, a complex suspension A visualization of the flow of concrete, a complex suspension. In this snapshot of the simulation, the stress on each suspended particle is shown color-coded with its specific value drawn on its surface. Suspended particles that have a stress value below a specific threshold value are shown in outline form in order to better view those particles that are carrying the majority of the stress in the system. This image and the software used to produce it was developed by Steven Satterfield, John Hagedorn, and John Kelso of the National Institute of Standards and Technology (NIST), and Marc Olano of NIST and the University of Maryland-Baltimore County. High Fidelity Simulation of Complex Suspension Flow for Practical Rheometry

332

Numerical studies for flow and heat transfer of the Powell-Eyring fluid thin film over an unsteady stretching sheet with internal heat generation using the chebyshev finite difference method  

Science Journals Connector (OSTI)

An analysis is carried out to study the unsteady two-dimensional Powell-Eyring flow and heat transfer to a laminar liquid film from a ... horizontal stretching surface in the presence of internal heat generation....

M. M. Khader; A. M. Megahed

2013-05-01T23:59:59.000Z

333

Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor  

SciTech Connect (OSTI)

The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

2011-04-01T23:59:59.000Z

334

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

335

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network [OSTI]

as other types of air source heat pumps, VRF systems needconventional packaged air source heat pumps. Typical GSHPis basically an air source heat pump), especially when the

Hong, Tainzhen

2010-01-01T23:59:59.000Z

336

E-Print Network 3.0 - aps high heat Sample Search Results  

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

heat Search Powered by Explorit Topic List Advanced Search Sample search results for: aps high heat Page: << < 1 2 3 4 5 > >> 1 The three partners have succeeded in halving the...

337

High Performance Flow Simulations on Graphics Processing Units  

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

High Performance Flow Simulations on Graphics Processing Units High Performance Flow Simulations on Graphics Processing Units Speaker(s): Wangda Zuo Date: June 17, 2010 - 12:00pm Location: 90-3122 Seminar Host/Point of Contact: Michael Wetter Building design and operation often requires real-time or faster-than-real-time simulations for detailed information on air distributions. However, none of the current flow simulation techniques can satisfy this requirement. To solve this problem, a Fast Fluid Dynamics (FFD) model has been developed. The FFD can solve Navier-Stokes equations at a speed of 50 times faster than Computational Fluid Dynamics (CFD). In addition, the computing speed of the FFD program has been further enhanced up to 30 times by executing in parallel on a Graphics Processing Unit (GPU) instead of a Central Processing Unit (CPU). As a whole, the FFD on a GPU

338

Gas-solid flow characteristics in high-density CFB  

Science Journals Connector (OSTI)

The gas-solid flow characteristics in the riser of a high density CFB of square (0.27 m×0.27 m×10...? 0.187m×10.4 m) cross section, using Geldart B particles (quartz sand), was investigated experimentally. The in...

Xue-yao Wang; Bao-guo Fan; Sheng-dian Wang; Xiang Xu…

2012-08-01T23:59:59.000Z

339

Reply To The Comment By D D Blackwell And G R Priest On Heat Flow From Four  

Open Energy Info (EERE)

Reply To The Comment By D D Blackwell And G R Priest On Heat Flow From Four Reply To The Comment By D D Blackwell And G R Priest On Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa By S E Ingebritsen, M A Scholl And D R Sherrod Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Reply To The Comment By D D Blackwell And G R Priest On Heat Flow From Four New Research Drill Holes In The Western Cascades, Oregon, Usa By S E Ingebritsen, M A Scholl And D R Sherrod Details Activities (1) Areas (1) Regions (0) Abstract: Unavailable Author(s): S. E. Ingebritsen, M. A. Scholl, D. R. Sherrod Published: Geothermics, 1996 Document Number: Unavailable DOI: Unavailable Source: View Original Journal Article Geothermal Literature Review At Breitenbush Hot Springs Area (Ingebritsen, Et Al., 1996)

340

DOE-HDBK-1012/3-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 3 of 3  

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

3-92 3-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 3 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576- 8401. FTS 626-8401. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019791 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was

Note: This page contains sample records for the topic "high heat flow" 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

DOE-HDBK-1012/2-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 2 of 3  

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

2-92 2-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 2 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; prices available from (615) 576- 8401. FTS 626-8401. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019790 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was

342

DOE-HDBK-1012/1-92; DOE Fundamentals Handbook Thermodynamics, Heat Transfer, and Fluid Flow Volume 1 of 3  

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

1-92 1-92 JUNE 1992 DOE FUNDAMENTALS HANDBOOK THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Volume 1 of 3 U.S. Department of Energy FSC-6910 Washington, D.C. 20585 Distribution Statement A. Approved for public release; distribution is unlimited. This document has been reproduced directly from the best available copy. Available to DOE and DOE contractors from the Office of Scientific and Technical Information. P. O. Box 62, Oak Ridge, TN 37831; (615) 576-8401. Available to the public from the National Technical Information Service, U.S. Department of Commerce, 5285 Port Royal Rd., Springfield, VA 22161. Order No. DE92019789 THERMODYNAMICS, HEAT TRANSFER, AND FLUID FLOW Rev. 0 HT ABSTRACT The Thermodynamics, Heat Transfer, and Fluid Flow Fundamentals Handbook was developed to assist nuclear facility operating contractors provide operators, maintenance

343

Heat flow determinations and implied thermal regime of the Coso geothermal  

Open Energy Info (EERE)

determinations and implied thermal regime of the Coso geothermal determinations and implied thermal regime of the Coso geothermal area, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Conference Proceedings: Heat flow determinations and implied thermal regime of the Coso geothermal area, California Details Activities (1) Areas (1) Regions (0) Abstract: Obvious surface manifestations of an anomalous concentration of geothermal energy at the Coso Geothermal Area, California, include fumarolic activity, active hot springs, and associated hydrothermally altered rocks. Abundant Pleistocene volcanic rocks, including a cluster of thirty-seven rhyolite domes, occupy a north-trending structural and topographic ridge near the center of an oval-shaped zone of late Cenozoic ring faulting. In an investigation of the thermal regime of the geothermal

344

LATERAL HEAT FLOW INFRARED THERMOGRAPHY FOR THICKNESS INDEPENDENT DETERMINATION OF THERMAL DIFFUSIVITY IN CFRP  

SciTech Connect (OSTI)

In conventional infrared thermography, determination of thermal diffusivity requires thickness information. Recently GE has been experimenting with the use of lateral heat flow to determine thermal diffusivity without thickness information. This work builds on previous work at NASA Langley and Wayne State University but we incorporate thermal time of flight (tof) analysis rather than curve fitting to obtain quantitative information. We have developed appropriate theoretical models and a tof based data analysis framework to experimentally determine all components of thermal diffusivity from the time-temperature measurements. Initial validation was carried out using finite difference simulations. Experimental validation was done using anisotropic carbon fiber reinforced polymer (CFRP) composites. We found that in the CFRP samples used, the in-plane component of diffusivity is about eight times larger than the through-thickness component.

Tralshawala, Nilesh; Howard, Don; Knight, Bryon; Plotnikov, Yuri; Ringermacher, Harry [Nondestructive Technologies Laboratory, GE--Global Research Center, Niskayuna, NY 12309 (United States)

2008-02-28T23:59:59.000Z

345

Heat flow of the Earth and resonant capture of solar 57-Fe axions  

E-Print Network [OSTI]

In a very conservative approach, supposing that total heat flow of the Earth is exclusively due to resonant capture inside the Earth of axions, emitted by 57-Fe nuclei on Sun, we obtain limit on mass of hadronic axion: m_aheat from decays of 40-K, 232-Th, 238-U inside the Earth, this estimation could be improved to the value: m_a<1.6 keV. Both the values are less restrictive than limits set in devoted experiments to search for 57-Fe axions (m_a<216-745 eV), but are much better than limits obtained in experiments with 83-Kr (m_a<5.5 keV) and 7-Li (m_a<13.9-32 keV).

F. A. Danevich; A. V. Ivanov; V. V. Kobychev; V. I. Tretyak

2008-11-24T23:59:59.000Z

346

Heat dissipation performance of a high-brightness LED package assembly using high-thermal conductivity filler  

Science Journals Connector (OSTI)

This paper presents a thermal analysis and experimental validation of natural convective heat transfer of a high-brightness light-emitting diode (LED) package assembly. The substrate...

Yung, K C; Liem, H; Choy, H S

2013-01-01T23:59:59.000Z

347

Numerical analysis of convective heat transfer characteristics of supercritical hydrocarbon fuel in cooling panel with local flow blockage structure  

Science Journals Connector (OSTI)

Abstract The convection heat transfer of hydrocarbon fuel at supercritical pressure has a great influence on the regenerative cooling technology of a scramjet engine. A three-dimensional numerical simulation was conducted for the convection transfer of hydrocarbon fuel in the cooling panel of a combustion chamber wall. And the flow field around the local flow blockage structure and the outlet flow rate distribution characteristics of fuel in the cooling channels were analyzed in detail. The results of analyses indicate that with the optimized local flow blockage structure, the outlet flow rate distribution of fuel among the cooling channels become more uniform, as the area of local flow dead zone decreases. However, as the fuel temperature increases, the dramatic variation of thermodynamic physical properties of fuel has a strong influence on the flow field around the local flow blockage structure. Especially, a local flow dead zone can be easily formed in the supercritical temperature region. Meanwhile, transverse pressure gradient around the throat region of blockage structure and additional loss, which is caused by turbulence fluctuation and energy exchange of fluid in the downstream area, affect the outlet flow rate distribution of fuel among the coolant passages seriously. It can therefore be concluded that the local flow blockage structure is more suitably designed in the subcritical temperature region by taking above-mentioned factors into consideration.

Yu Feng; Jiang Qin; Wen Bao; Qinchun Yang; Hongyan Huang; Zhongqi Wang

2014-01-01T23:59:59.000Z

348

Measurements of wall heat (mass) transfer for flow through blockages with round and square holes in a wide rectangular channel  

E-Print Network [OSTI]

COMMANDS . . APPENDIX C: UNCERTAINTY ANALYSIS . APPENDIX D: RAW DATA & RESULTS . . 71 . . . . 74 77 VITA. 134 vu1 LIST OF FIGURES Page Figurc 1 Internal and external cooling concepts used in modem gas turbine airfoils (Han et al. ). Figure 2... . . . . . . . . . . . . . . . . . . . . . . . . . 62 xt NOMENCLATURE A, flow cross-sectional area of test channel, m 2 surface area, m 2 D?hydraulic diameter of test channel, m friction factor f, reference friction factor for fully developed turbulent flow in smooth channel heat transfer...

Cervantes, Joel

2012-06-07T23:59:59.000Z

349

Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped Emmanuel Rousseau  

E-Print Network [OSTI]

Radiative heat transfer at nanoscale mediated by surface plasmons for highly doped silicon the role of surface plasmons for nanoscale radiative heat transfer between doped silicon surfaces. We derive a new accurate and closed-form expression of the radiative near- field heat transfer. We also

Paris-Sud XI, Université de

350

Heat generation from electronics increases with the advent of high-density integrated circuit technology. To  

E-Print Network [OSTI]

1 Abstract Heat generation from electronics increases with the advent of high-density integrated circuit technology. To come up with the heat generation, microscale cooling has been thought as a promising technology. Prediction of heat transfer rate is crucial in design of microscale cooling device

Boyer, Edmond

351

HIGH-POWER MILLIMETREWAVE TRANSMISSION SYSTEMS AND COMPONENTS FOR ELECTRON CYCLOTRON HEATING OF FUSION PLASMAS  

Science Journals Connector (OSTI)

At the Institute for Plasma Research at the University of Stuttgart, high-power millimetre wave transmission systems for electron cyclotron heating (ECRH) and current drive (ECCD)...

W. Kasparek; G. Dammertz; V. Erckmann…

2005-01-01T23:59:59.000Z

352

Observation of a high-confinement regime in a tokamak plasma with ion cyclotron resonance heating  

Science Journals Connector (OSTI)

The H mode in ion cyclotron-resonance-heated plasmas has been investigated with and without additional neutral beam injection. Ion cyclotron-resonance heating can cause the transition into a high-confinement regime (H mode) in combination with beam heating. The H mode, however, has also been realized—for the first time—with ion cyclotron-resonance heating alone in the D (H)-hydrogen minority scheme at an absorbed rf power of 1.1 MW.

K. Steinmetz et al.

1987-01-12T23:59:59.000Z

353

Thermodynamic Characteristic Study of a High-temperature Flow-rate Control Valve for Fuel Supply of Scramjet Engines  

Science Journals Connector (OSTI)

Thermodynamic characteristics are of great importance for the performance of a high-temperature flow-rate control valve, as high-temperature environment may bring problems, such as blocking of spool and increasing of leakage, to the valve. In this paper, a high-temperature flow-rate control valve, pilot-controlled by a pneumatic servo system is developed to control the fuel supply for scramjet engines. After introducing the construction and working principle, the thermodynamic mathematical models of the valve are built based on the heat transfer methods inside the valve. By using different boundary conditions, different methods of simulations are carried out and compared. The steady-state and transient temperature field distribution inside the valve body are predicted and temperatures at five interested points are measured. By comparing the simulation and experimental results, a reasonable 3D finite element analysis method is suggested to predict the thermodynamic characteristics of the high-temperature flow-rate control valve.

Wen ZENG; Zhizhong TONG; Songjing LI; Hongzhou LI; Liang ZHANG

2012-01-01T23:59:59.000Z

354

High performance in low-flow solar domestic hot water systems  

SciTech Connect (OSTI)

Low-flow solar hot water heating systems employ flow rates on the order of 1/5 to 1/10 of the conventional flow. Low-flow systems are of interest because the reduced flow rate allows smaller diameter tubing, which is less costly to install. Further, low-flow systems result in increased tank stratification. Lower collector inlet temperatures are achieved through stratification and the useful energy produced by the collector is increased. The disadvantage of low-flow systems is the collector heat removal factor decreases with decreasing flow rate. Many solar domestic hot water systems require an auxiliary electric source to operate a pump in order to circulate fluid through the solar collector. A photovoltaic driven pump can be used to replace the standard electrical pump. PV driven pumps provide an ideal means of controlling the flow rate, as pumps will only circulate fluid when there is sufficient radiation. Peak performance was always found to occur when the heat exchanger tank-side flow rate was approximately equal to the average load flow rate. For low collector-side flow rates, a small deviation from the optimum flow rate will dramatically effect system performance.

Dayan, M.

1997-12-31T23:59:59.000Z

355

Analysis of a high-temperature heat exchanger for an externally-fired micro gas turbine  

Science Journals Connector (OSTI)

Abstract The externally-fired gas turbine (EFGT) can convert fuels such as coal, biomass, biomass gasification gas and solar energy into electricity and heat. The combination of this technology with biomass gasification gas represents an interesting option for gasification, for which it has been difficult to find a conversion technology. In this system, the heat exchanger deals with the contaminants of biomass derived gas instead of the turbine itself. However, these contaminants can build a deposit layer in the heat exchanger that can affect its performance. The heat exchanger is important in externally fired gas turbines since the turbine inlet temperature is directly dependent on its performance. Several studies on heat exchangers for externally fired gas turbines have been carried out. However, very few detailed studies were found comparing the performance of heat exchangers for externally fired gas turbines considering the effect of deposit materials on the surfaces. In this regard, this work compares the performance of a corrugated plate heat exchanger and a two-tube-passes shell and tube heat exchanger considering the effect of thickness of deposit material with different thermal conductivities on pressure drop and effectiveness. The results show that the effectiveness of the corrugated plate heat exchanger is more influenced at larger thicknesses of deposit materials than the two-tube-passes shell and tube heat exchanger. There is an exponential increase in the pressure drop of the plate heat exchanger while a monotonic increase of pressure drop is seen for the shell and tube heat exchanger. The increase in the thickness of the deposit material has two effects. On one hand, it increases the resistance to heat transfer and on the other hand, it reduces the through flow area increasing the velocity and hence the heat transfer coefficient. Additionally, the effectiveness of the heat exchangers had a stronger influence on the power output than the pressure drop.

Fabiola Baina; Anders Malmquist; Lucio Alejo; Björn Palm; Torsten H. Fransson

2015-01-01T23:59:59.000Z

356

Heat transfer in channels with porous inserts during forced fluid flow  

Science Journals Connector (OSTI)

General analytic expressions are obtained to calculate heat transfer and temperature fields in a plane channel ... allowance for the effective thermal conductivity of the heat carrier and the distribution of heat

A. A. Plakseev; V. V. Kharitonov

1989-01-01T23:59:59.000Z

357

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

E-Print Network [OSTI]

necessary fluid mechanical and heat transfer data forCurvature on Heat Transfer to Incompressible Fluids," Trans.may transfer as much or more heat (to a moving fluid in

Yee, G.

2010-01-01T23:59:59.000Z

358

Comparison of energy efficiency between variable refrigerant flow systems and ground source heat pump systems  

E-Print Network [OSTI]

tool for geothermal water loop heat pump systems, 9thInternational IEA Heat Pump Conference, Zürich, Switzerland,Performance of ground source heat pump system in a near-zero

Hong, Tainzhen

2010-01-01T23:59:59.000Z

359

Electron heat flow in the solar corona: Implications of non-Maxwellian velocity distributions, the solar gravitational  

E-Print Network [OSTI]

Electron heat flow in the solar corona: Implications of non-Maxwellian velocity distributions, the solar gravitational field, and Coulomb collisions John C. Dorelli Space and Atmospheric Science Group, Los Alamos National Laboratory, Los Alamos, New Mexico, USA Jack D. Scudder Department of Physics

Scudder, Jack

360

Numerical Investigation on the Heat Transfer Enhancement Using Micro/Nano Phase-Change Particulate Flow.  

E-Print Network [OSTI]

??The introduction of phase change material fluid and nanofluid in micro-channel heat sink design can significantly increase the cooling capacity of the heat sink because… (more)

Xing, Keqiang

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Heat transfer and fluid flow characteristics of microchannels with internal longitudinal fins.  

E-Print Network [OSTI]

??Electronic components generate large amount of heat during their operation, which requires to be dissipated. Over the past decade, internal heat generation levels have exponentially… (more)

Foong, Andrew Jun Li

2009-01-01T23:59:59.000Z

362

High-heat-load synchrotron tests of room-temperature, silicon crystal monochromators at the CHESS F-2 wiggler station  

SciTech Connect (OSTI)

This note summarizes the results of the single crystal monochromator high-heat-load tests performed at the CHESS F-2 wiggler station. The results from two different cooling geometries are presented: (1) the ``pin-post`` crystal and (2) the ``criss-cross`` crystal. The data presented were taken in August 1993 (water-cooled pin-post) and in April 1995 (water- and gallium-cooled pin-post crystal and gallium-cooled criss-cross crystal). The motivation for trying these cooling (or heat exchanger) geometries is to improve the heat transfer efficiency over that of the conventional slotted crystals. Calculations suggest that the pin-post or the microchannel design can significantly improve the thermal performance of the crystal. The pin-post crystal used here was fabricated by Rocketdyne Albuquerque Operations. From the performance of the conventional slotted crystals, it was thought that increased turbulence in the flow pattern may also enhance the heat transfer. The criss-cross crystal was a simple attempt to achieve the increased flow turbulence. The criss-cross crystal was partly fabricated in-house (cutting, etching and polishing) and bonded by RAO. Finally, a performance comparison among all the different room temperature silicon monochromators that have been tested by the APS is presented. The data includes measurements with the slotted crystal and the core-drilled crystals. Altogether, the data presented here were taken at the CHESS F-2 wiggler station between 1991 and 1995.

Lee, W.K.; Fernandez, P.B.; Graber, T.; Assoufid, L.

1995-09-08T23:59:59.000Z

363

Project Profile: High Operating Temperature Liquid Metal Heat...  

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

investigating the use of metal alloys as a heat transfer fluid (HTF) in concentrating solar power (CSP) systems operating at temperatures in excess of 800C. By allowing higher...

364

Electrically Heated High Temperature Incineration of Air Toxics  

E-Print Network [OSTI]

In-Process Technology has placed a prototype of its patented, electrically heated, packed-bed air toxics oxidizer at a northern California chemical plant. This thermal oxidizer is capable of handling a wide range of chlorinated and non...

Agardy, F. J.; Wilcox, J. B.

365

Flow and Heat Transfer of a MHD Viscoelastic Fluid in a Channel with Stretching Walls: Some Applications to Haemodynamics  

E-Print Network [OSTI]

Of concern in the paper is a study of steady incompressible viscoelastic and electrically conducting fluid flow and heat transfer in a parallel plate channel with stretching walls in the presence of a magnetic field applied externally. The flow is considered to be governed by Walter's liquid B fluid. The problem is solved by developing a suitable numerical method. The results are found to be in good agrement with those of earlier investigations reported in existing scientific literatures. The study reveals that a back flow occurs near the central line of the channel due to the stretching walls and further that this flow reversal can be stopped by applying a strong external magnetic field. The study also shows that with the increase in the strength of the magnetic field, the fluid velocity decreases but the temperature increases. Thus the study bears potential applications in the study of the haemodynamic flow of blood in the cardiovascular system when subjected to an external magnetic field.

Misra, J C; Rath, H J

2010-01-01T23:59:59.000Z

366

On the heat flux vector for flowing granular materials--Part I: effective thermal conductivity and background  

SciTech Connect (OSTI)

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier’s law of heat conduction and for complex materials such as nonlinear fluids, porous media, or granular materials, the coeffcient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame-invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier’s law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non-linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or suffcient.

Massoudi, Mehrdad

2006-09-10T23:59:59.000Z

367

Evaporation heat transfer and friction characteristics of R-134a flowing downward in a vertical corrugated tube  

SciTech Connect (OSTI)

Differently from most previous studies, the heat transfer and friction characteristics of the pure refrigerant HFC-134a during evaporation inside a vertical corrugated tube are experimentally investigated. The double tube test sections are 0.5 m long with refrigerant flowing in the inner tube and heating water flowing in the annulus. The inner tubes are one smooth tube and two corrugated tubes, which are constructed from smooth copper tube of 8.7 mm inner diameter. The test runs are performed at evaporating temperatures of 10, 15, and 20 C, heat fluxes of 20, 25, and 30 kW/m{sup 2}, and mass fluxes of 200, 300, and 400 kg/m{sup 2} s. The quality of the refrigerant in the test section is calculated using the temperature and pressure obtained from the experiment. The pressure drop across the test section is measured directly by a differential pressure transducer. The effects of heat flux, mass flux, and evaporation temperature on the heat transfer coefficient and two-phase friction factor are also discussed. It is found that the percentage increases of the heat transfer coefficient and the two-phase friction factor of the corrugated tubes compared with those of the smooth tube are approximately 0-10% and 70-140%, respectively. (author)

Aroonrat, Kanit; Wongwises, Somchai [Fluid Mechanics, Thermal Engineering and Multiphase Flow Research Lab. (FUTURE), Department of Mechanical Engineering, King Mongkut's University of Technology Thonburi, Bangmod, Bangkok 10140 (Thailand)

2011-01-15T23:59:59.000Z

368

Studies on the effects of heat and high pressure treatmeants on fat globule surface layers in recombined milk.  

E-Print Network [OSTI]

??The present study examined the effects of heat treatment, high pressure (HP) treatment or combined heat and HP treatments, either before or after homogenization, on… (more)

Anantawat, Visaka

2011-01-01T23:59:59.000Z

369

Mixed convection flow and heat transfer in entrance region of rectangular ducts rotating about a parallel axis  

SciTech Connect (OSTI)

The objective of the present work is to investigate the laminar mixed convection flow and heat transfer in the entrance region of heated rectangular ducts rotating about a parallel axis. Heating conditions of isothermal and iso-flux are both considered. Boussinesq approximation is invoked to take into account buoyancy effect induced by centrifugal force. Navier-Stokes/Boussinesq system can be cast into a dimensionless form, in which five governing parameters, the Prandtl number Pr, rotational Reynolds number J, rotational Grashof number Gr{sub {Omega}}, aspect ratio {gamma} and the eccentricity E, are involved. Mechanisms of secondary vortex development in the ducts are explored by a theoretical analysis on vorticity transport equation. The values of Pr and E are fixed as 0.7 and 10, respectively. For various combinations of the other thee parameters, a vorticity-velocity method implemented with a marching technique is employed to solve the resultant three-dimensional system for simultaneously developing flow and temperature fields. The emphasis is placed on the rotational effects, including both coriolis force and centrifugal buoyancy; on the non-isothermal flow and the related heat transfer. The results reveal that the friction factors and heat transfer rates can be enhanced by Coriolis and rotation-induced buoyancy effects; and the variations of the local values are closely related to the evolution of the secondary vortices in ducts. The differences in flow behaviors and thermal characteristics for UWT and UHF are also investigated by the present theoretical analysis on secondary flow mechanism as well as the computational results.

Soong, C.Y. [Chung Cheng Inst. of Tech., Taoyuan (Taiwan, Province of China). Dept. of Aeronautical Engineering; Yan, W.M. [Hua Fan Coll. of Humanities and Technology, Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering

1995-12-31T23:59:59.000Z

370

Simulation of a High Efficiency Multi-bed Adsorption Heat Pump  

SciTech Connect (OSTI)

Attaining high energy efficiency with adsorption heat pumps is challenging due to thermodynamic losses that occur when the sorbent beds are thermally cycled without effective heat recuperation. The multi-bed concept described here effectively transfers heat from beds being cooled to beds being heated, which enables high efficiency in thermally driven heat pumps. A simplified lumped-parameter model and detailed finite element analysis are used to simulate the performance of an ammonia-carbon sorption compressor, which is used to project the overall heat pump coefficient of performance. The effects of bed geometry and number of beds on system performance are explored, and the majority of the performance benefit is obtained with four beds. Results indicate that a COP of 1.24 based on heat input is feasible at AHRI standard test conditions for residential HVAC equipment. When compared on a basis of primary energy input, performance equivalent to SEER 13 or 14 are theoretically attainable with this system.

TeGrotenhuis, Ward E.; Humble, Paul H.; Sweeney, J. B.

2012-05-01T23:59:59.000Z

371

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

E-Print Network [OSTI]

, simplest case of thermal conductivity where resistive scattering dominates C() v() l() d C() = heatTesting the physics of heat conduction using high pressure: crystals, glasses, and interfaces David supported by CDAC and AFOSR #12;The story... · Use high pressure (gem anvil cells) to modify vibrational

Braun, Paul

372

A New Heat Transfer Fluid for Concentrating Solar Systems: Particle Flow in Tubes  

Science Journals Connector (OSTI)

Abstract This paper demonstrates a new concept of heat transfer fluid (HTF) for CSP applications, developed in the frame of both a National and a European project (CSP2 FP7 project). It involves a dense suspension of small solid particles. This innovation is currently. The dense suspension of particles receiver (DSPR) consists in creating the upward circulation of a dense suspension of particles (solid fraction in the range 30%-40%) in vertical absorbing tubes submitted to concentrated solar energy. So the suspension acts as a heat transfer fluid with a heat capacity similar to a liquid HTF but only limited in temperature by the working temperature limit of the receiver tubes. Suspension temperatures up to 750 °C are expected for metallic tubes, thus opening new opportunities for high efficiency thermodynamic cycles such as supercritical steam and carbon dioxide. First experimental results were obtained during on-sun testing with CNRS solar facility of a single tube DSPR for an outlet temperature lower than 300 °C. In this lab-scale experimental setup, the solar absorber is a single opaque metallic tube, containing upward solid circulation, located inside a cylindrical cavity dug in a receiver made of refractory, and submitted to the concentrated solar radiation through a 0.10m x 0.50m slot. The absorber is a 42.4 mm o.d. stainless steel tube. SiC was used because of its thermal properties, availability and rather low cost. The 63.9 ?m particle mean diameter permits a good fluidization with almost no bubbles, for very low air velocities. Solar flux densities in the range 200-250 kW/m2 were tested resulting in solid temperature increase ranging between 50 and 150 °C. The mean wall-to-suspension heat transfer coefficient (h) was calculated from experimental data. It is very sensitive to the solid fraction of the solid suspension, which was varied from 27% to 36%. These latter values are one order of magnitude larger than the solid fraction in circulating fluidized beds operating at much higher air velocity. Heat transfer coefficients ranging from 140 to 500 W/m2.K have been obtained; i.e. 400 W/m2.K mean value for standard operating conditions at low temperature.

G. Flamant; D. Gauthier; H. Benoit; J.-L. Sans; B. Boissière; R. Ansart; M. Hemati

2014-01-01T23:59:59.000Z

373

High-frequency thermoacoustic-Stirling heat engine demonstration device  

Science Journals Connector (OSTI)

A small thermoacoustic-Stirling engine demonstration device that can produce sound in excess of 100 dB at 560 Hz has been constructed. The engine consists of a quarter wavelength acoustic resonator with a smaller diameter coaxial regenerator positioned toward the resonator’s closed end thereby forming an acoustic feedback path around the regenerator. Acoustic oscillations begin spontaneously when the hot heat exchanger adjoining one end of the regenerator is heated to a sufficient temperature. A water stream in a second heat exchanger maintains the opposite end of the regenerator near ambient temperature. This device was inspired by the Backhaus-Swift engine and is a preliminary step in the investigation of regenerator operation at frequencies much higher than may be practical with mechanical or free-piston Stirling engines.

Kevin J. Bastyr; Robert M. Keolian

2003-01-01T23:59:59.000Z

374

Liquid Salts as Media for Process Heat Transfer from VHTR's: Forced Convective Channel Flow Thermal Hydraulics, Materials, and Coating  

SciTech Connect (OSTI)

The goal of this NERI project was to perform research on high temperature fluoride and chloride molten salts towards the long-term goal of using these salts for transferring process heat from high temperature nuclear reactor to operation of hydrogen production and chemical plants. Specifically, the research focuses on corrosion of materials in molten salts, which continues to be one of the most significant challenges in molten salts systems. Based on the earlier work performed at ORNL on salt properties for heat transfer applications, a eutectic fluoride salt FLiNaK (46.5% LiF-11.5%NaF-42.0%KF, mol.%) and a eutectic chloride salt (32%MgCl2-68%KCl, mole %) were selected for this study. Several high temperature candidate Fe-Ni-Cr and Ni-Cr alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, were exposed to molten FLiNaK with the goal of understanding corrosion mechanisms and ranking these alloys for their suitability for molten fluoride salt heat exchanger and thermal storage applications. The tests were performed at 850��������C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion was noted to occur predominantly from dealloying of Cr from the alloys, an effect that was particularly pronounced at the grain boundaries Alloy weight-loss due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys���¢�������� weight-loss was also found to correlate to the concentration of carbon present for the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. Experiments involving molten salt exposures of Incoloy-800H in Incoloy-800H crucibles under an argon cover gas showed a significantly lower corrosion for this alloy than when tested in a graphite crucible. Graphite significantly accelerated alloy corrosion due to the reduction of Cr from solution by graphite and formation on Cr-carbide on the graphite surface. Ni-electroplating dramatically reduced corrosion of alloys, although some diffusion of Fe and Cr were observed occur through the Ni plating. A pyrolytic carbon and SiC (PyC/SiC) CVD coating was also investigated and found to be effective in mitigating corrosion. The KCl-MgCl2 molten salt was less corrosive than FLiNaK fluoride salts for corrosion tests performed at 850oC. Cr dissolution in the molten chloride salt was still observed and consequently Ni-201 and Hastelloy N exhibited the least depth of attack. Grain-boundary engineering (GBE) of Incoloy 800H improved the corrosion resistance (as measured by weight loss and maximum depth of attack) by nearly 50% as compared to the as-received Incoloy 800H sample. Because Cr dissolution is an important mechanism of corrosion, molten salt electrochemistry experiments were initiated. These experiments were performed using anodic stripping voltammetry (ASV). Using this technique, the reduction potential of Cr was determined against a Pt quasi-reference electrode as well as against a Ni(II)-Ni reference electrode in molten FLiNaK at 650 oC. The integrated current increased linearly with Cr-content in the salt, providing for a direct assessment of the Cr concentration in a given salt of unknown Cr concentration. To study heat transfer mechanisms in these molten salts over the forced and mixed convection regimes, a forced convective loop was constructed to measure heat transfer coefficients, friction factors and corrosion rates in different diameter tubes in a vertical up flow configuration in the laminar flow regime. Equipment and instrumentation for the forced convective loop was designed, constructed, and tested. These include a high temperature centrifugal pump, mass flow meter, and differential pressure sensing capabilities to an uncertainty of < 2 Pa. The heat transfer coefficient for the KCl-MgCl2 salt was measured in t

Kumar Sridharan; Mark Anderson; Todd Allen; Michael Corradini

2012-01-30T23:59:59.000Z

375

Advanced Alloys for Compact, High-Efficiency, High-Temperature Heat-Exchangers  

SciTech Connect (OSTI)

Oak Ridge National Laboratory (ORNL) has conducted research and development for several years which has been focused on the behavior and performance improvements of sheets and foils of various alloys for compact heat-exchangers (recuperators) for advanced microturbines. The performance and reliability of such thin sections are challenged at 650-750 C by fine grain size causing excessive creep, and by moisture effects greatly enhancing oxidation attack in exhaust gas environments. Standard 347 stainless steel has been used successfully at or below 600 C, but has suffered from both of these kinds of degradation at 650 C and above. Alloys have been identified which can have very good properties for such heat-exchangers, especially with careful control of microstructure during processing, including alloy 625, HR120 and the new AL20-25+Nb. These alloys, and the mechanistic understanding behind their behavior, are also applicable to achieving the better heat-exchanger technology needed for fuel cells or other high-temperature, clean-energy applications.

Maziasz, Philip J [ORNL; Pint, Bruce A [ORNL; Shingledecker, John P [ORNL; Evans, Neal D [ORNL; Yamamoto, Yukinori [ORNL; More, Karren Leslie [ORNL; Lara-Curzio, Edgar [ORNL

2006-01-01T23:59:59.000Z

376

Definition: Heat | Open Energy Information  

Open Energy Info (EERE)

Heat Heat Jump to: navigation, search Dictionary.png Heat Heat is the form of energy that is transferred between systems or objects with different temperatures (flowing from the high-temperature system to the low-temperature system). Also referred to as heat energy or thermal energy. Heat is typically measured in Btu, calories or joules. Heat flow, or the rate at which heat is transferred between systems, has the same units as power: energy per unit time (J/s).[1][2][3][4] View on Wikipedia Wikipedia Definition In physics and chemistry, heat is energy in transfer between a system and its surroundings other than by work or transfer of matter. The transfer can occur in two simple ways, conduction, and radiation, and in a more complicated way called convective circulation. Heat is not a property

377

Definition: Heat pump | Open Energy Information  

Open Energy Info (EERE)

pump pump Jump to: navigation, search Dictionary.png Heat pump Heating and/or cooling equipment that, during the heating season, draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside[1] View on Wikipedia Wikipedia Definition A heat pump is a device that transfers heat energy from a heat source to a heat sink against a temperature gradient. Heat pumps are designed to move thermal energy opposite the direction of spontaneous heat flow. A heat pump uses some amount of external high-grade energy to accomplish the desired transfer of thermal energy from heat source to heat sink. While compressor-driven air conditioners and freezers are familiar examples of heat pumps, the term "heat pump" is more general and applies to

378

The 1983 Temperature Gradient and Heat Flow Drilling Project for the State of Washington  

SciTech Connect (OSTI)

During the Summer of 1983, the Washington Division of Geology and Earth Resources carried out a three-hole drilling program to collect temperature gradient and heat flow information near potential geothermal resource target areas. The project was part of the state-coupled US Department of Energy Geothermal Program. Richardson Well Drilling of Tacoma, Washington was subcontracted through the State to perform the work. The general locations of the project areas are shown in figure 1. The first hole, DNR 83-1, was located within the Green River valley northwest of Mount St. Helens. This site is near the Green River Soda Springs and along the projection of the Mount St. Helens--Elk Lake seismic zone. The other two holes were drilled near Mount Baker. Hole DNR 83-3 was sited about 1/4 km west of the Baker Hot Springs, 10.5 km east of Mount Baker, while hole DNR 83-5 was located along Rocky Creek in the Sulphur Creek Valley. The Rocky Creek hole is about 10 km south-southwest of the peak. Two other holes, DNR 83-2 and DNR 83-4, were located on the north side of the Sulphur Creek Valley. Both holes were abandoned at early stages of drilling because of deep overburden and severe caving problems. The sites were apparently located atop old landslide deposits.

Korosec, Michael A.

1983-11-01T23:59:59.000Z

379

1983 temperature gradient and heat flow drilling project for the State of Washington  

SciTech Connect (OSTI)

During the Summer of 1983, a three-hole drilling program was carried out to collect temperature gradient and heat flow information near potential geothermal resource target areas. The general locations of the project areas are shown. The first hole, DNR 83-1, was located within the Green River valley northwest of Mount St. Helens. This site is near the Green River Soda Springs and along the projection of the Mount St. Helens - Elk Lake seismic zone. The other two holes were drilled near Mount Baker. Hole DNR 83-3 was sited about 1/4 km west of the Baker Hot Springs, 10.5 km east of Mount Baker, while hole DNR 83-5 was located along Rocky Creek in the Sulphur Creek Valley. The Rocky Creek hole is about 10 km south-southwest of the peak. Two other holes, DNR 83-2 and DNR 83-4, were located on the north side of the Sulphur Creek Valley. Both holes were abandoned at early stages of drilling because of deep overburden and severe caving problems. The sites were apparently located atop old landslide deposits.

Korosec, M.A.

1983-11-01T23:59:59.000Z

380

Ion Heating and High-Energy-Particle Production by Ion-Cyclotron Heating in the Large Helical Device  

Science Journals Connector (OSTI)

Ion-cyclotron heating was applied to the Large Helical Device. When the proton-cyclotron resonance was near the saddle point of the magnetic field-strength plane, strong ion-cyclotron damping occurred. Under these conditions efficient plasma heating was achieved for more than one minute. A high-energy ion tail was observed, and the effective tail temperature was determined by a balance between the wave acceleration and the electron-drag relaxation. There was no apparent sign of particle orbit loss effect in the investigated density range of 0.8–1.3×1019 m-3.

T. Mutoh et al.

2000-11-20T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Heat transfer process under a film-cooled surface with presence of weak swirling flow in the mainstream  

SciTech Connect (OSTI)

Experiments have been performed in a relatively large circular pipe to study and obtain the heat transfer data over a film-cooled surface, with the presence of weak swirling flow in the mainstream. The swirling flow is generated by a flat-vaned swirler situated upstream. A cooling film is injected from an annular slot formed by the pipe wall and the circular cover plate. The radial temperature distribution measurements at several axial locations were used to infer the film jet structure and the rate of mixing of the film jet with the swirling flow. The nondimensional parameters governing the heat transfer process under the film are derived from the system of governing equations. Experiments demonstrate that the swirl number, increasing with turbulence intensity and swirl velocity in the mainstream, can rapidly destroy the film jet structure and enhance the heat transfer process. During the course of the experiments, the blowing parameter ranged from 0.5 to 2 and the swirl number ranged from 0 to 0.6. Correlations for the Nusselt number which account for the effect of swirling flow are presented. (author)

Yang, C.S. [Department of Computer Science and Information Engineering, Far East University, Tainan (China); Kung, T.L.; Gau, C. [Institute of Aeronautics and Astronautics, Center for Micro/Nano Science and Technology, National Cheng Kung University (China)

2007-11-15T23:59:59.000Z

382

Changes in Hepatic Blood Flow During Transcatheter Arterial Infusion with Heated Saline in Hepatic VX2 Tumor  

SciTech Connect (OSTI)

Purpose. This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model. Methods. All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 Degree-Sign C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 Degree-Sign C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection. Results. After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group. Conclusions. The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

Cao Wei, E-mail: cawe-001@163.com [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Li Jing, E-mail: lijing02@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Burn and Plastic Surgery (China); Wu Zhiqun, E-mail: zhiqunwu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Zhou Changxi, E-mail: changxizhou@163.com [Chinese PLA General Hospital, Department of Respiratory Disease (China); Liu Xi, E-mail: xiliu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China); Wan Yi, E-mail: yiwan@163.com [The Fourth Military Medical University, Department of Health Statistics, Institute for Health Informatics (China); Duan Yunyou, E-mail: yunyouduan@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China)

2013-06-15T23:59:59.000Z

383

High Temperature Heat Recovery Systems Using Ceramic Recuperators  

E-Print Network [OSTI]

Ceramic shell and tube recuperators capable of providing up to 1800oF (980oC) preheated combustion air and operating at process gas inlet temperatures of up to 2800oF (1540oC) have shown themselves to be cost effective waste heat recovery devices...

Young, S. B.; Bjerklie, J. W.; York, W. A.

1980-01-01T23:59:59.000Z

384

A radiant flow reactor for high?temperature reactivity studies of pulverized solids  

Science Journals Connector (OSTI)

Our radiant two?phase flow reactor presents several new possibilities for high?temperature reactivity studies. Most importantly the thermal histories of the suspension and entrainment gas can be independently regulated over wide ranges. At low suspension loadings outlet temperatures can differ by hundreds of degrees and gas temperatures are low enough to inhibit hydrocarbon cracking chemistry so primary products are quenched as soon as they are expelled. With coal suspensions tars were generated with the highest H/C ratio and lowest proton aromaticity ever reported. Alternatively particles and gas can be heated at similar rates to promote secondary chemistry by increasing particle loading. Simply by regulating the furnace temperature arbitrary extents of conversion of coal tar into soot were observed for fixed total mass loss. Under both circumstances heat fluxes are comparable to those in large furnaces so relevant heating rates and reaction times are accessible. Suspensions remain optically thin even for the highest loadings of technological interest because they are only 1 cm wide. Consequently the macroscopic behavior remains firmly connected to single?particle phenomena. Mass and elemental closures are rarely breached by more than 5% in individual runs so interpretations are not subject to inordinate scatter in the data. The reactor is also well suited for combustion studies as demonstrated by extents of carbon and nitrogen burnout from 50% to 100% for various gas?stream oxygen levels.

John C. Chen; Stephen Niksa

1992-01-01T23:59:59.000Z

385

Downward two-phase flow effects in heat-loss and pressure-drop modeling of steam injection wells  

SciTech Connect (OSTI)

Modelling of the pressure drop and heat loss in steam injection wells has undergone a gradual evolution since the heavy interest in enhanced oil recovery by steam injection in the mid-60's. After briefly reviewing the evolution of steam models this paper presents a model which advances the state-of-the-art of steam modelling. The main advance presented in this paper is modelling the effects of the various flow regimens that occur during steam injection. The paper describes the formulation of a two-phase downward vertical flow pressure drop model which is not limited by the ''no-slip'' homogeneous flow assumptions in most previously published models. By using different correlations for mist, bubble, and slug flow, improved pressure drop calculations result, which in turn improve temperature predictions. The paper describes how the model handles temperature predictions differently in the single and two-phase steam flow situations. The paper also describes special features in the model to account for layered soil properties, soil dry out, cyclic injection, coupling heat losses, and reflux boiling in wet annuli. Two examples problems are presented which illustrate some of these features.

Galate, J.W.; Mitchell, R.F.

1985-03-01T23:59:59.000Z

386

Rotary magnetic heat pump  

DOE Patents [OSTI]

A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.

Kirol, L.D.

1987-02-11T23:59:59.000Z

387

Analytical and Numerical Study of Joule Heating Effects on Electrokinetically Pumped Continuous Flow PCR Chips  

E-Print Network [OSTI]

Analytical and Numerical Study of Joule Heating Effects on Electrokinetically Pumped Continuous, and the potential for integration.1-3 Joule heating is inevitable when electrokinetic pumping is used Form: December 8, 2007 Joule heating is an inevitable phenomenon for microfluidic chips involving

Le Roy, Robert J.

388

High speed flow cytometer droplet formation system and method  

DOE Patents [OSTI]

A droplet forming flow cytometer system allows high speed processing without the need for high oscillator drive powers through the inclusion of an oscillator or piezoelectric crystal such as within the nozzle volume or otherwise unidirectionally coupled to the sheath fluid. The nozzle container continuously converges so as to amplify unidirectional oscillations which are transmitted as pressure waves through the nozzle volume to the nozzle exit so as to form droplets from the fluid jet. The oscillator is directionally isolated so as to avoid moving the entire nozzle container so as to create only pressure waves within the sheath fluid. A variation in substance concentration is achieved through a movable substance introduction port which is positioned within a convergence zone to vary the relative concentration of substance to sheath fluid while still maintaining optimal laminar flow conditions. This variation may be automatically controlled through a sensor and controller configuration. A replaceable tip design is also provided whereby the ceramic nozzle tip is positioned within an edge insert in the nozzle body so as to smoothly transition from nozzle body to nozzle tip. The nozzle tip is sealed against its outer surface to the nozzle body so it may be removable for cleaning or replacement.

Van den Engh, Ger (Seattle, WA)

2000-01-01T23:59:59.000Z

389

Gravitational collapse of a spherical star with heat flow as a possible energy mechanism of gamma-ray bursts  

E-Print Network [OSTI]

We investigate the gravitational collapse of a spherically symmetric, inhomogeneous star, which is described by a perfect fluid with heat flow and satisfies the equation of state $p=\\rho/3$ at its center. In the process of the gravitational collapsing, the energy of the whole star is emitted into space. And the remaining spacetime is a Minkowski one without a remnant at the end of the process. For a star with a solar mass and solar radius, the total energy emitted is at the order of $10^{54}$ {\\rm erg}, and the time-scale of the process is about $8s$. These are in the typical values for a gamma-ray burst. Thus, we suggest the gravitational collapse of a spherical star with heat flow as a possible energy mechanism of gamma-ray bursts.

Zhe Chang; Cheng-Bo Guan; Chao-Guang Huang; Xin Li

2008-03-26T23:59:59.000Z

390

Analytical models of transient thermoelastic deformations of mirrors heated by high power cw laser beams  

E-Print Network [OSTI]

and are suspended in a vacuum vessel : the heat losses are only due to the thermal radiation. The resulting2243 Analytical models of transient thermoelastic deformations of mirrors heated by high power cw substrat. La distribution de température engendrée dans le substrat produit des déformations

Boyer, Edmond

391

The self-heating of damp cellulosic materials: I. High thermal conductivity and diffusivity  

Science Journals Connector (OSTI)

......self-heating of damp cellulosic materials: I. High thermal conductivity...stockpiles of cellulosic materials are analysed. The model...distinct bifurcation diagrams. In particular it is...stockpile sizes for materials prone to self-heating...surfaces by breakage on handling. In such circumstances......

R. A. SISSON; A. SWIFT; G. C. WAKE; B. F. GRAY

1992-01-01T23:59:59.000Z

392

Electronic Heating at High Bias in Atomic-Scale Au Break Junctions Ruoyu Chen,1  

E-Print Network [OSTI]

, U.S.A. Heating in nanoscale systems driven out of equilibrium is of fundamental importance, has O-10 Electronic Heating at High Bias in Atomic-Scale Au Break Junctions Ruoyu Chen,1, Texas, U.S.A. 2 Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005

393

RIS-M-2594 ELECTRON CYCLOTRON RESONANCE HEATING OF A HIGH-DENSITY PLASMA  

E-Print Network [OSTI]

RIS�-M-2594 ELECTRON CYCLOTRON RESONANCE HEATING OF A HIGH-DENSITY PLASMA Flemming Ramskov Hansen Abstract. Various schemes for electron cyclotron resonance heat- ing of tokamak plasmas with the ratio of electron plasma frequen- cy to electron cyclotron frequency, "»pe/^ce* larger than 1 on axis

394

Effects of the ship motion on gas–solid flow and heat transfer in a circulating fluidized bed  

Science Journals Connector (OSTI)

A series of experiments on a circulating fluidized bed (CFB) was performed to investigate the effects of ship motion on gas–solid flow and heat transfer in the CFB. Rolling period, rolling amplitude, inclination angle, superficial velocity, particle diameter range, and solid circulation flux were varied in the experiments. The following results were obtained: (1) When the CFB undergoes rolling motion, the downflow of particles changes periodically and the solid volume fraction increases at the riser bottom. As a result, the time-averaged total pressure drop of the CFB in rolling motion becomes larger than that at the upright attitude. Similarly, the total pressure drop of the CFB at an inclined attitude is larger than that at the upright attitude. (2) The total pressure drop of the CFB in rolling motion is hardly affected by rolling period. As rolling amplitude increases, on the other hand, the effects of rolling motion become more remarkable. From these results, it is concluded that gravity dominantly affects gas–solid flow in the system. (3) At an inclined attitude, the symmetry of the flow field with respect to the riser center plane breaks, and heat transfer at the lower wall of the riser is promoted. As inclination angle increases, heat transfer augmentation becomes more remarkable. Similarly, the heat transfer coefficient in rolling motion is larger than that at the upright attitude. (4) Heat transfer augmentation by ship motion is concluded to be caused by the direct contact between solid particles and the heater surface owing to the vertical component of gravity to the surface.

Hiroyuki Murata; Hideyuki Oka; Masaki Adachi; Kazuyoshi Harumi

2012-01-01T23:59:59.000Z

395

Heat exchanger design considerations for high temperature gas-cooled reactor (HTGR) plants  

SciTech Connect (OSTI)

Various aspects of the high-temperature heat exchanger conceptual designs for the gas turbine (HTGR-GT) and process heat (HTGR-PH) plants are discussed. Topics include technology background, heat exchanger types, surface geometry, thermal sizing, performance, material selection, mechanical design, fabrication, and the systems-related impact of installation and integration of the units in the prestressed concrete reactor vessel. The impact of future technology developments, such as the utilization of nonmetallic materials and advanced heat exchanger surface geometries and methods of construction, is also discussed.

McDonald, C.F.; Vrable, D.L.; Van Hagan, T.H.; King, J.H.; Spring, A.H.

1980-02-01T23:59:59.000Z

396

High Performance Computing linear algorithms for two-phase flow in porous media  

E-Print Network [OSTI]

High Performance Computing linear algorithms for two-phase flow in porous media Robert Eymard High Performance Computing techniques. This implies to handle the difficult problem of solving

Paris-Sud XI, Université de

397

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

SciTech Connect (OSTI)

A multidimensional, mountain-scale, thermal-hydrologic (TH) numerical model is presented for investigating unsaturated flow behavior in response to decay heat from the radioactive waste repository in the Yucca Mountain unsaturated zone (UZ), Nevada. The model, consisting of both two-dimensional (2-D) and three-dimensional (3-D) representations of the UZ repository system, is based on the current repository design, drift layout, thermal loading scenario, and estimated current and future climate conditions. This mountain-scale TH model evaluates the coupled TH processes related to mountain-scale UZ flow. It also simulates the impact of radioactive waste heat release on the natural hydrogeological system, including heat-driven processes occurring near and far away from the emplacement tunnels or drifts. The model simulations predict thermally perturbed liquid saturation, gas- and liquid-phase fluxes, and water and rock temperature elevations, as well as the changes in water flux driven by evaporation/condensation processes and drainage between drifts. These simulations provide mountain-scale thermally perturbed flow fields for assessing the repository performance under thermal loading conditions.

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

2005-05-25T23:59:59.000Z

398

High Temperature Variable Conductance Heat Pipes for Radioisotope Stirling Systems  

SciTech Connect (OSTI)

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

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

2009-03-16T23:59:59.000Z

399

The GTE Ceramic Recuperator for High Temperature Waste Heat Recovery  

E-Print Network [OSTI]

Steel Bllffalo Metal Casting Standard St.eel N.ati_onal Forge Ladish Co. Pr.Jt.t & \\.fllitney Ama", Specl."11t.v Metals Bethlehem Steel Cape Ann Forge Staolev Spring (TRw) Box Forge Reheat, Steel Box Forge Reheat, Steel 1 Box Forge Reheat...,807 1.9 1.8 31 St.andard Steel Burnham, PA Box forge. Reheat, Steel 32 National Forge Erie, PA Ladle Preheater. Steel :,.} Lad isb Co. Cyntbiaca, ....'Y Box Heat Treat, Steell 188.426 77,527 3. Pra t t & \\.on i tney East Hart.ford, CT Box...

Dorazio, R. E.; Gonzalez, J. M.; Ferri, J. L.; Rebello, W. J.; Ally, M. R.

1984-01-01T23:59:59.000Z

400

Fluid flow and heat transfer across an elliptical hollow fiber membrane tube bank with randomly distributed features  

Science Journals Connector (OSTI)

Abstract An elliptical hollow fiber membrane tube bank (EHFMTB) has better performances while being employed for air humidification. The EHFMTB is populated in a plastic shell to form a shell-and-tube heat exchanger like membrane contactor. The tube bank is always randomly populated in practical applications because of convenience and randomness in the manufacturing process. The fluid flow and heat transfer across a randomly distributed elliptical hollow fiber membrane tube bank (REHFMTB) are investigated. To disclose the influences of the fiber arrangements on the performances, three unit cells containing 20 fibers with different randomly distributions are selected as the calculating domains. A renormalization group k–? (RNG KE) turbulence model with enhanced wall treatment is used for solving the equations governing the momentum and heat transports. The friction factor and Nusselt number across the REHFMTB under various fiber distributions, Reynolds numbers (Re), packing fractions (?) and elliptical semiaxis ratios (b/a) are numerically obtained and experimentally validated. It is found that the comprehensive heat transfer performance is deteriorated for the fluid flow across the REHFMTB.

Runhua Jiang; Minlin Yang; Sheng Chen; Si-Min Huang; Xiaoxi Yang

2014-01-01T23:59:59.000Z

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401

High energy bursts from a solid state laser operated in the heat capacity limited regime  

DOE Patents [OSTI]

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

1996-06-11T23:59:59.000Z

402

High energy bursts from a solid state laser operated in the heat capacity limited regime  

DOE Patents [OSTI]

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes.

Albrecht, Georg (Livermore, CA); George, E. Victor (Livermore, CA); Krupke, William F. (Pleasanton, CA); Sooy, Walter (Pleasanton, CA); Sutton, Steven B. (Manteca, CA)

1996-01-01T23:59:59.000Z

403

High-Performance Thermoelectric Devices Based on Abundant Silicide Materials for Vehicle Waste Heat Recovery  

Broader source: Energy.gov [DOE]

Development of high-performance thermoelectric devices for vehicle waste heat recovery will include fundamental research to use abundant promising low-cost thermoelectric materials, thermal management and interfaces design, and metrology

404

Local characteristics of heat-radiation superconductor detectors based on high-temperature superconductor films  

Science Journals Connector (OSTI)

Relations are proposed for evaluating the local values of the thermal sensitivity, speed of response, and resolution of a heat radiation detector based on high-temperature superconductor films.

O. S. Esikov; A. I. Krot; I. G. Merinov…

1992-06-01T23:59:59.000Z

405

High Efficiency Microturbine with Integral Heat Recovery- Presentation by Capstone Turbine Corporation, June 2011  

Broader source: Energy.gov [DOE]

Presentation on High Efficiency Microturbine with Integral Heat Recovery, given by John Nourse of Capstone Turbine Corporation, at the U.S. DOE Industrial Distributed Energy Portfolio Review Meeting in Washington, D.C. on June 1-2, 2011.

406

Coronal Heating and Acceleration of the High/Low-Speed Solar Wind by Fast/Slow MHD Shock Trains  

E-Print Network [OSTI]

We investigate coronal heating and acceleration of the high- and low-speed solar wind in the open field region by dissipation of fast and slow magnetohydrodynamical (MHD) waves through MHD shocks. Linearly polarized \\Alfven (fast MHD) waves and acoustic (slow MHD) waves travelling upwardly along with a magnetic field line eventually form fast switch-on shock trains and hydrodynamical shock trains (N-waves) respectively to heat and accelerate the plasma. We determine one dimensional structure of the corona from the bottom of the transition region (TR) to 1AU under the steady-state condition by solving evolutionary equations for the shock amplitudes simultaneously with the momentum and proton/electron energy equations. Our model reproduces the overall trend of the high-speed wind from the polar holes and the low-speed wind from the mid- to low-latitude streamer except the observed hot corona in the streamer. The heating from the slow waves is effective in the low corona to increase the density there, and plays an important role in the formation of the dense low-speed wind. On the other hand, the fast waves can carry a sizable energy to the upper level to heat the outer corona and accelerate the high-speed wind effectively. We also study dependency on field strength, $B_0$, at the bottom of the TR and non-radial expansion of a flow tube, $f_{\\rm max}$, to find that large $B_0/f_{\\rm max}\\gtrsim 2$ but small $B_0\\simeq 2$G are favorable for the high-speed wind and that small $B_0/f_{\\rm max}\\simeq 1$ is required for the low-speed wind.

Takeru K. Suzuki

2003-12-22T23:59:59.000Z

407

Experimental investigations of uncovered-bundle heat transfer and two-phase mixture-level swell under high-pressure low heat-flux conditions. [PWR  

SciTech Connect (OSTI)

Results are reported from a series of uncovered-bundle heat transfer and mixture-level swell tests. Experimental testing was performed at Oak Ridge National Laboratory in the Thermal Hydraulic Test Facility (THTF). The THTF is an electrically heated bundle test loop configured to produce conditions similar to those in a small-break loss-of-coolant accident. The objective of heat transfer testing was to acquire heat transfer coefficients and fluid conditions in a partially uncovered bundle. Testing was performed in a quasi-steady-state mode with the heated core 30 to 40% uncovered. Linear heat rates varied from 0.32 to 2.22 kW/m.rod (0.1 to 0.68 kW/ft.rod). Under these conditions peak clad temperatures in excess of 1050 K (1430/sup 0/F) were observed, and total heat transfer coefficients ranged from 0.0045 to 0.037 W/cm/sup 2/.K (8 to 65 Btu/h.ft/sup 2/./sup 0/F). Spacer grids were observed to enhance heat transfer at, and downstream of, the grid. Radiation heat transfer was calculated to account for as much as 65% of total heat transfer in low-flow tests.

Anklam, T. M.; Miller, R. J.; White, M. D.

1982-03-01T23:59:59.000Z

408

Use of a Heat Flow Meter to Determine Active PCM Content in an Insulation  

SciTech Connect (OSTI)

Residential and commercial roofs and walls are currently designed and tested using steady-state criteria. The resulting R-values, based on the apparent thermal conductivity, are used by building standards as an important measure of energy performance. Building envelope components, however, are subject to dynamic environmental conditions. This mismatch between the steady-state principles used in design and code requirements and their dynamic operation results in relatively low thermal efficiencies. Although several research centers have developed experimental methods for transient analysis of building envelopes, there are no standardized testing procedures available for screening materials and systems for which performance depends on dynamic response. For example, a full-scale dynamic evaluation of phase change materials (PCMs) is needed to assess their energy saving benefits. A nationally accepted small-scale (one to two foot size specimens) testing procedure is not available for the analysis of dynamic thermal characteristics of conventional thermal mass systems or PCM-enhanced materials. At the same time, data on these characteristics are necessary for whole-building simulations, energy analysis, and energy code work. The transient characteristics of PCM-enhanced products depend on the PCM content and quality. The only readily available method of thermal evaluation uses the differential scanning calorimeter. Unfortunately, this method requires small, relatively uniform test specimens. This requirement is unrealistic in the case of PCM-enhanced building envelope products such as PCM-cellulose, PCM-glass fiber, or PCM-gypsum blends. Small specimens are not representative of PCM-based blends, since these materials are not homogeneous. Jan Kosny and David Yarbrough, Oak Ridge National Laboratory, P.O. Box 2008, MS 6070, Oak Ridge, TN 37831-6070. Elizabeth Kossecka, Polish Academy of Sciences, Institute of Fundamental Technological Research, Pawinskiego 5 B, 02-106, Warsaw, Poland. A procedure for making dynamic heat-flow measurements using existing instrumentation has been developed to analyze the benefits of thermal storage. This small-scale testing method is useful for thermal analysis and as a potential quality control method for producers of PCM-enhanced building materials. The research may provide the basis for consensus standard development. This paper uses as an example a dynamic testing process for PCM-enhanced cellulose insulation.

Kosny, Jan [ORNL] [ORNL; Kossecka, Elizabeth [Institute of Fundamental Technological Research, Polish Academy of Sciences] [Institute of Fundamental Technological Research, Polish Academy of Sciences; Yarbrough, David W [ORNL] [ORNL

2010-01-01T23:59:59.000Z

409

Study of Heat Transfer in Non-boiling Two-phase Gas-liquid Flow in Pipes for Horizontal, Slightly Inclined, and Vertical Orientations.  

E-Print Network [OSTI]

??The main objective of this research is to establish a fundamental understanding of heat transfer in non-boiling two-phase pipe flow. The key processes that govern… (more)

Tang, Clement Chih-Wei

2011-01-01T23:59:59.000Z

410

Finite difference analysis of mass transfer effects on flow past an impulsively started infinite vertical plate in dissipative fluid and constant heat flux  

Science Journals Connector (OSTI)

A finite-difference solution to the flow past an impulsively started infinite vertical plate is derived by assuming 1) presence of species concentration like water vapour, CO2 etc. and 2) constant heat flux at th...

J. N. Das; S. N. Ray; Prof. Dr. V. M. Soundalgekar

1995-02-01T23:59:59.000Z

411

Convective heat transfer in the vertical channel flow of a clear fluid adjacent to a nanofluid layer: a two-fluid model  

Science Journals Connector (OSTI)

A two-fluid vertical channel flow and convective heat transfer model in which one of the two fluids is a nanofluid demonstrates that the nanofluid can modify the fluid velocity at the interface of the two fluids,...

Robert A. Van Gorder; K. V. Prasad; K. Vajravelu

2012-07-01T23:59:59.000Z

412

Experimental investigation on heat transfer characteristics of magnetic fluid flow around a fine wire under the influence of an external magnetic field  

SciTech Connect (OSTI)

Experimental investigation is conducted to get insight into convective heat transfer features of the aqueous magnetic fluid flow over a fine wire under the influence of an external magnetic field. The convective heat transfer coefficient of the aqueous magnetic fluid flow around the heated wire is measured in both the uniform magnetic field and the magnetic field gradient. The effects of the external magnetic field strength and its orientation on the thermal behaviors of the magnetic fluids are analyzed. The experimental results show that the external magnetic field is a vital factor that affects the convective heat transfer performances of the magnetic fluids and the control of heat transfer processes of a magnetic fluid flow can be possible by applying an external magnetic field. (author)

Li, Qiang; Xuan, Yimin [School of Power Engineering, Nanjing University of Science and Technology, 200 Xiao Ling Wei, Nanjing 210094 (China)

2009-04-15T23:59:59.000Z

413

Unsteady effects in dense, high speed, particle laden flows J.D. Regele a,  

E-Print Network [OSTI]

t Dense high speed non-compacted multiphase flows exist in variable phase turbines, explosions, and ejec multiphase flows can be found in a variety of practical applications such as variable phase turbines

Dabiri, John O.

414

Effect of Beam Quality on the Scaling of High-Energy Flow Lasers  

Science Journals Connector (OSTI)

The maximum output power from high-energy flow lasers is primarily determined by the ... field intensity, however, depends on the beam quality that can be achieved with the laser ... of gas flow inhomogeneities o...

W. L. Bohn; Th. Hall

1987-01-01T23:59:59.000Z

415

Spatial association between the locations of roots and water flow paths in highly structured soil  

E-Print Network [OSTI]

Considerable evidence exists that the majority of low tension water flow through highly structured clayey soil occurs in a small fraction of total pore space and that the flow paths converge as depth increases. In structured clayey soils, water...

Gardiner, Nathan Thomas

2005-02-17T23:59:59.000Z

416

HEATS OF COMBUSTION OF HIGH TEMPERATURE POLYMERS Richard N. Walters*, Stacey M. Hackett* and Richard E. Lyon  

E-Print Network [OSTI]

1 HEATS OF COMBUSTION OF HIGH TEMPERATURE POLYMERS Richard N. Walters*, Stacey M. Hackett Creek Avenue, Building C Egg Harbor Township, New Jersey 08234 ABSTRACT The heats of combustion to thermochemical calculations of the net heat of combustion from oxygen consumption and the gross heat

Laughlin, Robert B.

417

High Water Heating Bills on Lockdown at Idaho Jail | Department of Energy  

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

High Water Heating Bills on Lockdown at Idaho Jail High Water Heating Bills on Lockdown at Idaho Jail High Water Heating Bills on Lockdown at Idaho Jail August 19, 2010 - 12:05pm Addthis The Blaine County Public Safety Facility houses between 60 and 80 prisoners and roughly 30 staffers. | Photo courtesy of Blaine The Blaine County Public Safety Facility houses between 60 and 80 prisoners and roughly 30 staffers. | Photo courtesy of Blaine Lindsay Gsell What does this project do? The new solar thermal hot water system will provide nearly 70 percent of the BTUs required for heating 600,000 gallons of water for the jail annually, saving the county more than $4,000 a year in electricity costs at current rates. In Hailey, Idaho, one 330,000 square foot building - the Blaine County Public Safety Facility - accounts for the county's highest operational

418

Numerical analysis of laminar fluid flow and heat transfer in a parallel plate channel with normally in-line positioned plates  

E-Print Network [OSTI]

NUMERICAL ANALYSIS OF LAMINAR FLUID FLOW AND HEAT TRANSFER IN A PARALLEL PLATE CHANNEL WITH NORMALLY IN-LINE POSITIONED PLATES A Thesis by JOHN GRADY iVICMATH Submitted to the Office of Graduate Studies of Texas AkM University in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1991 Major Subject: Mechanical Engineering NUMERICAL ANALYSIS OF LAMINAR FLUID FLOW AND HEAT TRANSFER IN A PARALLEL PLATE CHANNEI WITH NORMALLY IN-LINE POSITIONED PLATES A...

McMath, John Grady

2012-06-07T23:59:59.000Z

419

High rate heating driven decomposition of energetic materials: Diagnostics evaluation  

SciTech Connect (OSTI)

Combustion of energetic materials involves processes in both gas and condensed phases and is governed by coupled thermal, physical, and chemical phenomena. Development of reliable models for design, performance, stability, and hazard analyses requires detailed understanding of three general chemical reaction regimes: (1) initial condensed-phase decomposition, (2) subsequent interaction of decomposition products with the remaining condensed phase, and (3) gas-phase reaction of decomposition products to form the ultimate combustion products. The first two regimes are the least understood and most difficult to study, particularly the initial condensed-phase decomposition. The basic difficulty in studying condensed phase phenomena has been the inability to probe directly chemistry in the condensed phase under isothermal condition and with the spatial and temporal resolution needed at higher temperatures and reaction rates. Thin-film samples provide a means to study condensed-phase chemistry at isothermal conditions and with microsecond temporal resolution. We are developing an experiment system that employs rapidly heated thin- film samples and multiple diagnostics to examine condensed-phase chemistry and monitor evolved gas species. Results from our initial work have been encouraging. Thin-film samples of several energetic materials have been prepared and appear to be representative of bulk materials. Furthermore, preliminary experiments indicate that all the use of these samples with two chemical diagnostic techniques, time-of- flight mass spectrometry (TOFMS) and time-resolved infrared spectral photography (TRISP), is viable. 5 refs., 8 figs.

Trott, W.M.; Renlund, A.M.; Erickson, K.L.; Skocypec, R.D.

1991-01-01T23:59:59.000Z

420

High rate heating driven decomposition of energetic materials: Diagnostics evaluation  

SciTech Connect (OSTI)

Combustion of energetic materials involves processes in both gas and condensed phases and is governed by coupled thermal, physical, and chemical phenomena. Development of reliable models for design, performance, stability, and hazard analyses requires detailed understanding of three general chemical reaction regimes: (1) initial condensed-phase decomposition, (2) subsequent interaction of decomposition products with the remaining condensed phase, and (3) gas-phase reaction of decomposition products to form the ultimate combustion products. The first two regimes are the least understood and most difficult to study, particularly the initial condensed-phase decomposition. The basic difficulty in studying condensed phase phenomena has been the inability to probe directly chemistry in the condensed phase under isothermal condition and with the spatial and temporal resolution needed at higher temperatures and reaction rates. Thin-film samples provide a means to study condensed-phase chemistry at isothermal conditions and with microsecond temporal resolution. We are developing an experiment system that employs rapidly heated thin- film samples and multiple diagnostics to examine condensed-phase chemistry and monitor evolved gas species. Results from our initial work have been encouraging. Thin-film samples of several energetic materials have been prepared and appear to be representative of bulk materials. Furthermore, preliminary experiments indicate that all the use of these samples with two chemical diagnostic techniques, time-of- flight mass spectrometry (TOFMS) and time-resolved infrared spectral photography (TRISP), is viable. 5 refs., 8 figs.

Trott, W.M.; Renlund, A.M.; Erickson, K.L.; Skocypec, R.D.

1991-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners  

DOE Patents [OSTI]

A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

Thode, Lester E. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

422

Effervescent heating: constraints from nearby cooling flow clusters observed with XMM-Newton  

E-Print Network [OSTI]

We have used deprojected radial density and temperature profiles of a sample of 16 nearby CF clusters observed with XMM-Newton to test whether the effervescent heating model can satisfactorily explain the dynamics of CF clusters. For each cluster we derived the required extra heating as a function of cluster-centric distance for various values of the unknown parameters $\\dot M$ (mass deposition rate) and $f_c$ (conduction efficiency). We fitted the extra heating curve using the AGN effervescent heating function and derived the AGN parameters $L$ (the time-averaged luminosity) and $r_0$ (the scale radius where the bubbles start rising in the ICM). While we do not find any solution with the effervescent heating model for only one object, we do show that AGN and conduction heating are not cooperating effectively for half of the objects in our sample. For most of the clusters we find that, when a comparison is possible, the derived AGN scale radius $r_0$ and the observed AGN jet extension have the same order of magnitude. The AGN luminosities required to balance radiative losses are substantially lowered if the fact that the AGN deposits energy within a finite volume is taken into account. For the Virgo cluster, we find that the AGN power derived from the effervescent heating model is in good agreement with the observed jet power.

Rocco Piffaretti; Jelle Kaastra

2006-02-16T23:59:59.000Z

423

Electrical heating of soils using high efficiency electrode patterns and power phases  

DOE Patents [OSTI]

Powerline-frequency electrical (joule) heating of soils using a high efficiency electrode configuration and power phase arrangement. The electrode configuration consists of several heating or current injection electrodes around the periphery of a volume of soil to be heated, all electrodes being connected to one phase of a multi-phase or a single-phase power system, and a return or extraction electrode or electrodes located inside the volume to be heated being connected to the remaining phases of the multi-phase power system or to the neutral side of the single-phase power source. This electrode configuration and power phase arrangement can be utilized anywhere where powerline frequency soil heating is applicable and thus has many potential uses including removal of volatile organic compounds such as gasoline and tricholorethylene (TCE) from contaminated areas.

Buettner, Harley M. (Livermore, CA)

1999-01-01T23:59:59.000Z

424

Experimental and numerical investigation of turbulent flow and heat (mass) transfer in a two-pass trapezoidal channel with turbulence promoters  

E-Print Network [OSTI]

of three-dimensional flow and heat transfer also were performed for the trapezoidal channel with and without 90º ribs tested by Lee et al. (2007). Reynolds stress turbulence model (RSM) in the FLUENT CFD code was used to calculate the heat transfer...

Oh, Sung Hyuk

2009-05-15T23:59:59.000Z

425

Waste Heat Recovery from High Temperature Off-Gases from Electric Arc Furnace  

SciTech Connect (OSTI)

This article presents a study and review of available waste heat in high temperature Electric Arc Furnace (EAF) off gases and heat recovery techniques/methods from these gases. It gives details of the quality and quantity of the sensible and chemical waste heat in typical EAF off gases, energy savings potential by recovering part of this heat, a comprehensive review of currently used waste heat recovery methods and potential for use of advanced designs to achieve a much higher level of heat recovery including scrap preheating, steam production and electric power generation. Based on our preliminary analysis, currently, for all electric arc furnaces used in the US steel industry, the energy savings potential is equivalent to approximately 31 trillion Btu per year or 32.7 peta Joules per year (approximately $182 million US dollars/year). This article describes the EAF off-gas enthalpy model developed at Oak Ridge National Laboratory (ORNL) to calculate available and recoverable heat energy for a given stream of exhaust gases coming out of one or multiple EAF furnaces. This Excel based model calculates sensible and chemical enthalpy of the EAF off-gases during tap to tap time accounting for variation in quantity and quality of off gases. The model can be used to estimate energy saved through scrap preheating and other possible uses such as steam generation and electric power generation using off gas waste heat. This article includes a review of the historical development of existing waste heat recovery methods, their operations, and advantages/limitations of these methods. This paper also describes a program to develop and test advanced concepts for scrap preheating, steam production and electricity generation through use of waste heat recovery from the chemical and sensible heat contained in the EAF off gases with addition of minimum amount of dilution or cooling air upstream of pollution control equipment such as bag houses.

Nimbalkar, Sachin U [ORNL; Thekdi, Arvind [E3M Inc; Keiser, James R [ORNL; Storey, John Morse [ORNL

2014-01-01T23:59:59.000Z

426

Precision control of high temperature furnaces using an auxiliary power supply and charged practice current flow  

DOE Patents [OSTI]

Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved.

Pollock, George G. (San Ramon, CA)

1997-01-01T23:59:59.000Z

427

Precision control of high temperature furnaces using an auxiliary power supply and charged particle current flow  

DOE Patents [OSTI]

Two power supplies are combined to control a furnace. A main power supply heats the furnace in the traditional manner, while the power from the auxiliary supply is introduced as a current flow through charged particles existing due to ionized gas or thermionic emission. The main power supply provides the bulk heating power and the auxiliary supply provides a precise and fast power source such that the precision of the total power delivered to the furnace is improved. 5 figs.

Pollock, G.G.

1997-01-28T23:59:59.000Z

428

Numerical Simulation of Heat Transfer and Fluid Flow Characteristics of Server Rack in Datacenter  

Science Journals Connector (OSTI)

This chapter is studying the fluid mechanics and heat transfer of single server rack using the computational fluid dynamics software. The ... effect of the different structure parameters of server rack in datacen...

Jianfei Zhang; Donghao Liu; Xiping Qiao…

2014-01-01T23:59:59.000Z

429

Computational Analysis of Fluid Flow and Heat Transfer Characteristics of Obliquely Impinging Slot Jets  

Science Journals Connector (OSTI)

The skin friction and heat transfer characteristics due to a slot jet impinging obliquely on a flat plate are presented. The boundary layer equations are solved by a finite difference marching technique, detai...

S. Jayaraj; Vijay K. Garg

1988-01-01T23:59:59.000Z

430

Summary of Modern Nodal Integral Methods in Fluid Flow and Heat Transfer  

Science Journals Connector (OSTI)

Modern nodal integral methods are a product of original applications in neutron diffusion and neutron transport calculations. These methods have recently been applied to two-dimensional dynamic heat transfer and

G. L. Wilson; R. A. Rydin

1990-01-01T23:59:59.000Z

431

In-Situ Thermal Conductivity Testing Using a Portable Heat Flow Meter  

E-Print Network [OSTI]

A method has been developed for measuring heat losses from insulated systems in the field. While the measurements are not as precise as those made under laboratory conditions, they are more indicative of actual in service conditions. Extensive field...

Harr, K. S.; Hutto, F. B., Jr.

1979-01-01T23:59:59.000Z

432

Corrosion behavior in high heat input welded heat-affected zone of Ni-free high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel  

SciTech Connect (OSTI)

The pitting corrosion and interphase corrosion behaviors in high heat input welded heat-affected zone (HAZ) of a metastable high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel were explored through electrochemical tests. The HAZs were simulated using Gleeble simulator with high heat input welding condition of 300 kJ/cm and the peak temperature of the HAZs was changed from 1200 °C to 1350 °C, aiming to examine the effect of ?-ferrite formation on corrosion behavior. The electrochemical test results show that both pitting corrosion resistance and interphase corrosion resistance were seriously deteriorated by ?-ferrite formation in the HAZ and their aspects were different with increasing ?-ferrite fraction. The pitting corrosion resistance was decreased by the formation of Cr-depleted zone along ?-ferrite/austenite (?) interphase resulting from ?-ferrite formation; however it didn't depend on ?-ferrite fraction. The interphase corrosion resistance depends on the total amount of Cr-depleted zone as well as ferrite area and thus continuously decreased with increasing ?-ferrite fraction. The different effects of ?-ferrite fraction on pitting corrosion and interphase corrosion were carefully discussed in terms of alloying elements partitioning in the HAZ based on thermodynamic consideration. - Highlights: • Corrosion behavior in the weld HAZ of high-nitrogen austenitic alloy was studied. • Cr{sub 2}N particle was not precipitated in high heat input welded HAZ of tested alloy. • Pitting corrosion and interphase corrosion show a different behavior. • Pitting corrosion resistance was affected by whether or not ?-ferrite forms. • Interphase corrosion resistance was affected by the total amount of ?-ferrite.

Moon, Joonoh, E-mail: mjo99@kims.re.kr; Ha, Heon-Young; Lee, Tae-Ho

2013-08-15T23:59:59.000Z

433

Development of a High Performance Air Source Heat Pump for the US Market  

SciTech Connect (OSTI)

Heat pumps present a significant advantage over conventional residential heating technologies due to higher energy efficiencies and less dependence on imported oil. The US development of heat pumps dates back to the 1930 s with pilot units being commercially available in the 1950 s. Reliable and cost competitive units were available in the US market by the 1960 s. The 1973 oil embargo led to increased interest in heat pumps prompting significant research to improve performance, particularly for cold climate locations. Recent increasing concerns on building energy efficiency and environmental emissions have prompted a new wave of research in heat pump technology with special emphasis on reducing performance degradation at colder outdoor air temperatures. A summary of the advantages and limitations of several performance improvement options sought for the development of high performance air source heat pump systems for cold climate applications is the primary focus of this paper. Some recommendations for a high performance cold climate heat pump system design most suitable for the US market are presented.

Abdelaziz, Omar [ORNL] [ORNL; Shen, Bo [ORNL] [ORNL; Gao, Zhiming [ORNL] [ORNL; Baxter, Van D [ORNL] [ORNL; Iu, Ipseng [ORNL] [ORNL

2011-01-01T23:59:59.000Z

434

The Difficulty of the Heating of Cluster Cooling Flows by Sound Waves and Weak Shocks  

E-Print Network [OSTI]

We investigate heating of the cool core of a galaxy cluster through the dissipation of sound waves and weak shocks excited by the activities of the central active galactic nucleus (AGN). Using a weak shock theory, we show that this heating mechanism alone cannot reproduce observed temperature and density profiles of a cluster, because the dissipation length of the waves is much smaller than the size of the core and thus the wave energy is not distributed to the whole core.

Yutaka Fujita; Takeru Ken Suzuki

2006-10-19T23:59:59.000Z

435

6th International Symposium on Multiphase Flow, Heat Mass Transfer and Energy Conversion Xi'an, China, 11-15 July 2009  

E-Print Network [OSTI]

6th International Symposium on Multiphase Flow, Heat Mass Transfer and Energy Conversion Xi in pipeline transportation, where it is important to identify and control bottlenecks influence on production be viewed as the hydrodynamic equivalent of the Mach number for gas flows. Simplified hydraulic theories

Al Hanbali, Ahmad

436

Oxidation and Volatilization from Tungsten Brush High Heat Flux Armor During High Temperature Steam Exposure  

SciTech Connect (OSTI)

Tungsten brush accommodates thermal stresses and high heat flux in fusion reactor components such as plasma facing surfaces or armor. However, inherently higher surface areas are introduced with the brush design. We have tested a specific design of tungsten brush in steam between 500 and 1100°C. Hydrogen generation and tungsten volatilization rates were determined to address fusion safety issues. The brush prepared from 3.2-mm diameter welding rods had a packing density of 85 percent. We found that both hydrogen generation and tungsten volatilization from brush, fixtured to represent a unit within a larger component, were less than projections based upon the total integrated surface area (TSA). Steam access and the escape of hydrogen and volatile oxide from void spaces within the brush are restricted compared to specimens with more direct diffusion pathways to the test environment. Hydrogen generation rates from restrained specimens based on normal surface area (NSA) remain about five times higher than rates based on total surface areas from specimens with direct steam access. Volatilization rates from restrained specimens based upon normal surface area (NSA) were only 50 percent higher than our historic cumulative maximum flux plot (CMFP) for tungsten. This study has shown that hydrogen generation and tungsten volatilization from brush do not scale according to predictions with previously determined rates, but in fact, with higher packing density could approach those from flat surfaces.

Smolik, Galen Richard; Pawelko, Robert James; Anderl, Robert Andrew; Petti, David Andrew

2000-05-01T23:59:59.000Z

437

Gas temperature profiles at different flow rates and heating rates suffice to estimate kinetic parameters for fluidised bed combustion  

SciTech Connect (OSTI)

Experimental work on estimation kinetic parameters for combustion was conducted in a bench-scale fluidised bed (FB: 105x200mm). Combustion medium was obtained by using an electrical heater immersed into the bed. The ratio of heating rate (kJ/s) to molar flow rate of air (mol/s) regulated by a rheostat so that the heat of combustion (kJ/mol) can be synthetically obtained by an electrical power supply for relevant O{sub 2}-feedstock concentration (C{sub 0}). O{sub 2}-restriction ratio ({beta}) was defined by the ratio of O{sub 2}-feedstock concentration to O{sub 2}-air concentration (C{sub O{sub 2}-AIR}) at prevailing heating rates. Compressed air at further atmospheric pressure ({approx_equal}102.7kPa) entered the bed that was alumina particles (250{mu}m). Experiments were carried out at different gas flow rates and heating rates. FB was operated with a single charge of (1300g) particles for obtaining the T/T{sub 0} curves, and than C/C{sub 0} curves. The mathematical relationships between temperature (T) and conversion ratio (X) were expressed by combining total energy balance and mass balance in FB. Observed surface reaction rate constants (k{sub S}) was obtained from the combined balances and proposed model was also tested for these kinetic parameters (frequency factor: k{sub 0}, activation energy: E{sub A}, and reaction order: n) obtained from air temperature measurements. It was found that the model curves allow a good description of the experimental data. Thus, reaction rate for combustion was sufficiently expressed. (author)

Suyadal, Y. [Faculty of Engineering, Department of Chemical Engineering, Ankara University, 06100-Tandogan, Ankara (Turkey)

2006-07-15T23:59:59.000Z

438

Fluid flow and conjugated heat transfer in arbitrarily shaped channels via single domain formulation and integral transforms  

Science Journals Connector (OSTI)

Abstract The present work advances a recently introduced approach based on combining the Generalized Integral Transform Technique (GITT) and a single domain reformulation strategy, aimed at providing hybrid numerical–analytical solutions to convection–diffusion problems in complex physical configurations and irregular geometries. The methodology has been previously considered in the analysis of conjugated conduction–convection heat transfer problems, simultaneously modeling the heat transfer phenomena at both the fluid streams and the channels walls, by making use of coefficients represented as space variable functions with abrupt transitions occurring at the fluid–wall interfaces. The present work is aimed at extending this methodology to deal with both fluid flow and conjugated heat transfer within arbitrarily shaped channels and complex multichannel configurations, so that the solution of a cumbersome system of coupled partial differential equations defined for each individual sub-domain of the problem is avoided, with the proposition of the single-domain formulation. The reformulated problem is integral transformed through the adoption of eigenvalue problems containing the space variable coefficients, which provide the basis of the eigenfunction expansions and are responsible for recovering the transitional behavior among the different regions in the original formulation. For demonstration purposes, an application is first considered consisting of a microchannel with an irregular cross-section shape, representing a typical channel micro-fabricated through laser ablation, in which heat and fluid flow are investigated, taking into account the conjugation with the polymeric substrate. Then, a complex configuration consisting of multiple irregularly shaped channels is more closely analyzed, in order to illustrate the flexibility and robustness of the advanced hybrid approach. In both cases, the convergence behavior of the proposed expansions is presented and critical comparisons against purely numerical approaches are provided.

Diego C. Knupp; Renato M. Cotta; Carolina P. Naveira-Cotta

2014-01-01T23:59:59.000Z

439

Effect of flow topology on the calculation of two-phase frictional multipliers in uniformly heated flow of R-134a in a rectangular duct  

SciTech Connect (OSTI)

The two-phase frictional multipliers for SUVA R-134a flowing in a rectangular duct (with D{sub H} = 4.8 mm) have been measured for three nominal system pressures (0.88, 1.34 and 2.34 MPa) and four nominal mass fluxes (510, 1020 and 1740, 2040 kg/m{sup 2}/s) under uniform heat flux conditions. The data is compared with adiabatic data previously taken at similar flow conditions, as well as with several classical multiplier correlations. The comparisons reveal a strong effect of pressure and mass flux on the flow topology and, by extension, a large effect on the calculation of acceleration and frictional pressure drop components. For this fluid and this geometry, entrainment and fluid separation is enhanced at higher pressures and mass flux such that most of the liquid exists in the test section edges and as dispersed droplets in the core. For these cases, the classical simplified approach to calculate acceleration pressure drop fails to adequately predict the acceleration component and leads to erroneous calculations of frictional pressure drop from the measured total pressure drop. Best estimates of the true acceleration component are given, based on void profiles measured with a gamma densitometer system, comparisons to the adiabatic data, and recasting the data in terms of the total pressure drop multiplier as a function of the Martinelli parameter, X{sub tt}. (author)

Vassallo, Peter; Kevin Cope, W.; Smith, Walter C. [Bechtel Marine Propulsion Corporation, Niskayuna, NY 12309 (United States)

2010-11-15T23:59:59.000Z

440

High temperature latent heat thermal energy storage: Phase change materials, design considerations and performance enhancement techniques  

Science Journals Connector (OSTI)

Abstract A very common problem in solar power generation plants and various other industrial processes is the existing gap between the period of thermal energy availability and its period of usage. This situation creates the need for an effective method by which excess heat can be stored for later use. Latent heat thermal energy storage is one of the most efficient ways of storing thermal energy through which the disparity between energy production or availability and consumption can be corrected, thus avoiding wastage and increasing the process efficiency. This paper reviews a series of phase change materials, mainly inorganic salt compositions and metallic alloys, which could potentially be used as storage media in a high temperature (above 300 °C) latent heat storage system, seeking to serve the reader as a comprehensive thermophysical properties database to facilitate the material selection task for high temperature applications. Widespread utilization of latent heat storage systems has been held back by the poor thermal conductivity and some other inherent drawbacks of the use of PCMs; this paper reviews several heat transfer and performance enhancement techniques proposed in the literature and discusses a number of design considerations that must be taken into account aiming to provide a broad overview for the design of high temperature latent heat based thermal energy storage systems.

Bruno Cárdenas; Noel León

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high heat flow" 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

High order lattice Boltzmann models for gas flow on a wide range of Knudsen number  

E-Print Network [OSTI]

High order lattice Boltzmann models for gas flow on a wide range of Knudsen number L´eonard de, 2011) The lattice Boltzmann methods (LBM) have successfully been applied to micro-scale flows], which are micro-metric system flows driven by macroscopic pumps. The Lattice Boltzmann Method (LBM) has

Paris-Sud XI, Université de

442

Electron Heating by the Ion Cyclotron Instability in Collisionless Accretion Flows. I. Compression-Driven Instabilities and the Electron Heating Mechanism  

E-Print Network [OSTI]

In systems accreting well below the Eddington rate, the plasma in the innermost regions of the disk is collisionless and two-temperature, with the ions hotter than the electrons. Yet, whether a collisionless faster-than-Coulomb energy transfer mechanism exists in two-temperature accretion flows is still an open question. We study the physics of electron heating during the growth of ion velocity-space instabilities, by means of multi-dimensional particle-in-cell (PIC) simulations. A large-scale compression - embedded in a novel form of the PIC equations - continuously amplifies the field. This constantly drives a pressure anisotropy P_perp > P_parallel, due to the adiabatic invariance of the particle magnetic moments. We find that, for ion plasma beta values beta_i ~ 5-30 appropriate for the midplane of low-luminosity accretion flows, mirror modes dominate if the electron-to-proton temperature ratio is > 0.2, whereas if it is m_e/m_i - governed by the conservation of the magnetic moment in the growing fields ...

Sironi, Lorenzo

2014-01-01T23:59:59.000Z

443

High Performance Computing Based Methods for Simulation and Optimisation of Flow Problems.  

E-Print Network [OSTI]

??The thesis is concerned with the study of methods in high-performance computing for simulation and optimisation of flow problems that occur in the framework of… (more)

Bockelmann, Hendryk

2010-01-01T23:59:59.000Z

444

Unsteady hydromagnetic free-convection flow with radiative heat transfer in a rotating fluid  

Science Journals Connector (OSTI)

We study the unsteady free-convection flow near a moving infinite flat plate in a totating medium by imposing a time-dependent perturbation on a constant plate temperature. The temperatures involved are assume...

A. R. Bestman; S. K. Adjepong

445

Large-Eddy Simulation of Flow and Pollutant Transport in Urban Street Canyons with Ground Heating  

E-Print Network [OSTI]

Our study employed large-eddy simulation (LES) based on a one-equation subgrid-scale model to investigate the flow field and pollutant dispersion characteristics inside urban street canyons. Unstable thermal stratification ...

Li, Xian-Xiang

446

Modular High-Temperature Gas-Cooled Reactor short term thermal response to flow and reactivity transients  

SciTech Connect (OSTI)

The analyses reported here have been conducted at the Oak Ridge National Laboratory (ORNL) for the US Nuclear Regulatory Commission's (NRC's) Division of Regulatory Applications of the Office of Nuclear Regulatory Research. The short-term thermal response of the Modular High-Temperature Gas-Cooled Reactor (MHTGR) is analyzed for a range of flow and reactivity transients. These include loss of forced circulation (LOFC) without scram, moisture ingress, spurious withdrawal of a control rod group, hypothetical large and rapid positive reactivity insertion, and a rapid core cooling event. The coupled heat transfer-neutron kinetics model is also described.

Cleveland, J.C.

1988-01-01T23:59:59.000Z

447

High-Harmonic Fast-Wave Power Flow along Magnetic Field Lines in the Scrape-Off Layer of NSTX  

Science Journals Connector (OSTI)

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

R. J. Perkins; J. C. Hosea; G. J. Kramer; J.-W. Ahn; R. E. Bell; A. Diallo; S. Gerhardt; T. K. Gray; D. L. Green; E. F. Jaeger; M. A. Jaworski; B. P. LeBlanc; A. McLean; R. Maingi; C. K. Phillips; L. Roquemore; P. M. Ryan; S. Sabbagh; G. Taylor; J. R. Wilson

2012-07-27T23:59:59.000Z

448

High-Harmonic Fast-Wave Power Flow Along Magnetic Field Lines in the Scrape-Off Layer of NSTX  

SciTech Connect (OSTI)

A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive.

Perkins, R. J. [Princeton Plasma Physics Laboratory (PPPL); Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Ahn, Joonwook [ORNL; Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Diallo, A. [Princeton Plasma Physics Laboratory (PPPL); Gerhardt, S. [Princeton Plasma Physics Laboratory (PPPL); Gray, T. K. [Oak Ridge National Laboratory (ORNL); Green, David L [ORNL; Jaeger, Erwin Frederick [ORNL; Jaworski, M. A. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); McLean, Adam G [ORNL; Maingi, Rajesh [ORNL; Phillips, C. K. [Princeton Plasma Physics Laboratory (PPPL); Roquemore, L. [Princeton Plasma Physics Laboratory (PPPL); Ryan, Philip Michael [ORNL; Sabbagh, S. A. [Columbia University; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)

2012-01-01T23:59:59.000Z

449

High heat flux testing capabilities at Sandia National Laboratories - New Mexico  

SciTech Connect (OSTI)

High heat flux testing for the United States fusion power program is the primary mission of the Plasma Materials Test Facility (PMTF) located at Sandia National Laboratories - New Mexico. This facility, which is owned by the United States Department of Energy, has been in operation for over 17 years and has provided much of the high heat flux data used in the design and evaluation of plasma facing components for many of the world`s magnetic fusion, tokamak experiments. In addition to domestic tokamaks such as Tokamak Fusion Test Reactor (TFTR) at Princeton and the DIII-D tokamak at General Atomics, components for international experiments like TEXTOR, Tore-Supra, and JET also have been tested at the PMTF. High heat flux testing spans a wide spectrum including thermal shock tests on passively cooled materials, thermal response and thermal fatigue tests on actively cooled components, critical heat flux-burnout tests, braze reliability tests and safety related tests. The objective of this article is to provide a brief overview of the high heat flux testing capabilities at the PMTF and describe a few of the experiments performed over the last year.

Youchison, D.L.; McDonald, J.M.; Wold, L.S.

1994-12-31T23:59:59.000Z

450

Performance of an optimally contact-cooled high-heat-load mirror at the APS.  

SciTech Connect (OSTI)

X-ray undulator beamlines at third-generation synchrotrons facilities use either a monochromator or a mirror as the first optical element. In this paper, the thermal and optical performance of an optimally designed contact-cooled high-heat-load x-ray mirror used as the first optical element on the 2ID undulator beamline at the Advanced Photon Source (APS) is reported. It is shown that this simple and economical mirror design can comfortably handle the high heat load of undulator beamlines and provide good performance with long-term reliability and ease of operation. Availability and advantages of such mirrors can make the mirror-first approach to high-heat-load beamline design an attractive alternative to monochromator-first beamlines in many circumstances.

Cai, Z.; Khounsary, A.; Lai, B.; McNulty, I.; Yun, W.

1998-11-18T23:59:59.000Z

451

Large-dimension, high-ZT Thermoelectric Nanocomposites for High-Power High-efficiency Waste Heat Recovery for Electricity Generation  

Broader source: Energy.gov [DOE]

Large-dimension, high-ZT BiTe and Pb-based nanocomposites produced with a low-cost scalable process were used for development and testing of TE module prototypes, and demonstration of a waste heat recovery system

452

Welding of dissimilar alloys for high temperature heat exchangers for SOFC  

SciTech Connect (OSTI)

Reduction in the cost of balance of plant applications is one of the top priority focus areas for the successful implementation of solid oxide fuel cell technology. High temperature heat exchangers are employed to heat cathode air utilizing either hot gases coming from the anode side of the stack or other hot gases generated by external processes. In order to reduce the cost of heat exchangers, it may be necessary to apply several different materials, each in a different temperature zone, for the construction of the heat exchanger. This technique would require the joining of dissimilar materials in the construction. In this work, welding of commercial candidate dissimilar materials is explored. Filler materials were identified using equilibrium phase diagrams and thermodynamic simulation software. Autogenous welding was performed and the welding defects were characterized. Finally, experimental weld microstructures were compared to phases predicted by the simulations.

Wilson, R.D.; Hatem, J.; Dogan, O.N.; King, P.E.

2006-10-01T23:59:59.000Z

453

1 Shen 2/14/00 A5: High Heat Load Design 2/22/00  

E-Print Network [OSTI]

.............................................. 21 Heat transfer by forced convection .......................... 22 Basic fluid dynamics ................................................ 12 Heat transfer basics ............................................. 15 Three modes of heat transfer convective heat transfer ....................... 27 Thermal deformation and stress

Shen, Qun

454

Uncertainty in unprotected loss-of-heat-sink, loss-of-flow, and transient-overpower accidents.  

SciTech Connect (OSTI)

The sensitivities of various output parameters to selected input parameters in unprotected combined loss of heat-sink and loss-of-flow (ULOHS), loss-of-flow (ULOF), and transient-overpower (UTOP) accidents are explored in this report. This line of investigation was suggested by R. A. Wigeland. For an initial examination of potential sensitivities, the MATWS computer program has been compiled as part of a dynamic link library (DLL) so that uncertain input parameters can be sampled from their probability distributions using the GoldSim simulation software. The MATWS program combines the point-kinetics module from the SAS4A/SASSYS computer code with a simplified representation of the reactor heat removal system. Coupling with the GoldSim software by means of a DLL not only provides a convenient mechanism for sampling the stochastic input parameters but also allows the use of various tools that are available in GoldSim for analyzing the dependence of various MATWS outputs on these parameters. Should a decision be made to continue this investigation, the techniques used to couple MATWS and GoldSim could also be applied to couple the SAS4A/SASSYS computer code with GoldSim. The work described here illustrates the type of results that can be obtained from the stochastic analysis.

Morris, E. E.; Nuclear Engineering Division

2007-10-08T23:59:59.000Z

455

Dynamic Heat Flow Measurements to Study the Distribution of Phase-Change Material in an Insulation Matrix  

SciTech Connect (OSTI)

Phase change materials (PCMs) are used in building envelopes in many forms. The PCMs may be encased in discrete pouches or containers, or they may be distributed within another medium, such as in a board or within a loose fill product. In addition, most PCM products are blends containing fire retardants and chemical stabilizers. However, the current test method to measure the dynamic characteristics of PCMs, the differential scanning calorimeter (DSC), requires specimens that are relatively uniform and very small. Considering the limitations of DSC test results when applied to more complex PCM building envelope applications, we developed a combined experimental analytical protocol to determine the amount of phase-change energy actually available to provide thermal storage. This paper presents this new methodology for performing dynamic heat flow analysis of complex PCM-enhanced building materials. The experimental analytical protocol uses a conventional heat-flow apparatus and three-dimensional (3-D), finite-difference modeling. Based upon results from this methodology, ORNL researchers developed a simplified one-dimensional (1-D) model that can be easily used in whole-building simulations. This paper describes this methodology as applied to an insulation assembly containing a complex array of PCM pouches.

Kosny, Jan [ORNL] [ORNL; Stovall, Therese K [ORNL] [ORNL; Yarbrough, David W [ORNL] [ORNL

2010-01-01T23:59:59.000Z

456

Numerical analysis of the scavenge flow and convective heat transfer in large two-stroke marine diesel engines  

Science Journals Connector (OSTI)

Abstract A novel computational fluid dynamics (CFD) model is presented for the study of the scavenging process and convective heat transfer in a large two-stroke low-speed uniflow-scavenged marine diesel engine. The engine is modeled using a fully resolved 12° sector, corresponding to one scavenge port, with cyclic boundaries in the tangential direction. The CFD model is strongly coupled to experiments and effectively provides a high order “interpolation” of the engine processes through the solution of the Reynolds-Averaged Navier–Stokes (RANS) equations subject to boundary conditions obtained through experiments. The imposed experimental data includes time histories of the pressure difference across the engine and the heat release during combustion. The model is validated by a numerical sensitivity analysis and through a comparison of model predictions and experimental data, which shows a good agreement. The results show an effective scavenging and a low convective heat loss in agreement with experimental data for large marine diesel engines.

E. Sigurdsson; K.M. Ingvorsen; M.V. Jensen; S. Mayer; S. Matlok; J.H. Walther

2014-01-01T23:59:59.000Z

457

STOCHASTIC HEATING, DIFFERENTIAL FLOW, AND THE ALPHA-TO-PROTON TEMPERATURE RATIO IN THE SOLAR WIND  

SciTech Connect (OSTI)

We extend previous theories of stochastic ion heating to account for the motion of ions along the magnetic field B . We derive an analytic expression for the temperature ratio T{sub i}/T{sub p} in the solar wind assuming that stochastic heating is the dominant ion heating mechanism, where T{sub i} is the perpendicular temperature of species i and T{sub p} is the perpendicular proton temperature. This expression describes how T{sub i}/T{sub p} depends upon U{sub i} and ?{sub ?p}, where U{sub i} is the average velocity along B of species i in the proton frame and ?{sub ?p} is the ratio of the parallel proton pressure to the magnetic pressure, which we take to be ?< 1. We compare our model with previously published measurements of alpha particles and protons from the Wind spacecraft. We find that stochastic heating offers a promising explanation for the dependence of T{sub ?}/T{sub p} on U{sub ?} and ?{sub ?p} when the fractional cross helicity and Alfvén ratio at the proton-gyroradius scale have values that are broadly consistent with solar-wind measurements. We also predict how the temperatures of other ion species depend on their drift speeds.

Chandran, B. D. G.; Verscharen, D.; Isenberg, P. A.; Bourouaine, S. [Space Science Center and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States); Quataert, E. [Astronomy Department and Theoretical Astrophysics Center, 601 Campbell Hall, The University of California, Berkeley, CA 94720 (United States); Kasper, J. C., E-mail: benjamin.chandran@unh.edu, E-mail: s.bourouaine@unh.edu, E-mail: phil.isenberg@unh.edu, E-mail: daniel.verscharen@unh.edu, E-mail: eliot@astro.berkeley.edu, E-mail: jkasper@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2013-10-10T23:59:59.000Z

458

DRAIN-BACK PROTECTED LOW-FLOW SOLAR HEATING SYSTEM WITH DISTRIBUTED ELEVATED THERMALLY STRATIFIED STORAGE  

Science Journals Connector (OSTI)

ABSTRACT Design considerations concerning a drain-back freeze and overheat protection system are given with emphasis on nitrogen management and thermal stratification of an elevated distributed storage. The actual system of GNT in Berg, Federal Republic of Germany is described. KEYWORDS Solar Heating; Freeze Protection; Overheat Protection; Drain-Back System;

W.B. VELTKAMP; J. VAN BERKEL; A.T. KEESMAN

1990-01-01T23:59:59.000Z

459

Analysis of Heat Flow Data—I Detailed Observations in a Single Borehole  

Science Journals Connector (OSTI)

......determination of a single borehole may be considerablygreater...selected30-msection of borehole may yield a useful heat...Resourcesfor financing the drilling of the borehole; to the National Research...for pointing out the large amount of climatic information......

A. E. Beck; A. S. Judge

1969-10-01T23:59:59.000Z

460

Plasma flow at a high Mach-number  

SciTech Connect (OSTI)

Unlike the case of static magnetohydrodynamic (MHD) equilibria, where an expansion in large aspect ratio of toroidal devices is common, cases of MHD equilibria with flow are rarely treated this way, and when this is done the expansion tends to be only partial. The main reason for the difference seems to be the difficulty of expanding the larger system of equilibrium equations with flow. Here, we use a recent expansion technique which employs a variational principle to simplify the process [E. Hameiri, Phys. Plasmas 20, 024504 (2013)]. We treat four cases of MHD equilibria with flow, developing their asymptotic expansions in full, and for an application consider the effect of the flow on the Shafranov shift.

Yu, Bing; Hameiri, Eliezer [Courant Institute of Mathematical Sciences, New York University New York, New York 10012 (United States)] [Courant Institute of Mathematical Sciences, New York University New York, New York 10012 (United States)

2013-09-15T23:59:59.000Z

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461

A flow integrated DSD hydrodynamics strategy for computing the motion of detonation of insensitive high explosives on an Eulerian grid  

SciTech Connect (OSTI)

The detonation structure in many insensitive high explosives consists of two temporally disparate zones of heat release. In PBX 9502, there is a fast reaction zone ({approx} 25 ns) during which reactants are converted to gaseous products and small carbon clusters, followed by a slower regime ({approx} 250 ns) of carbon coagulation. A hybrid approach for determining the propagation of two-stage heat release detonations has been developed that utilizes a detonation shock dynamics (DSD) based strategy for the fast reaction zone with a direct hydrodynamic simulation of the flow in the slow zone. Unlike a standard DSD/programmed bum formulation, the evolution of the fast zone DSD-like surface is coupled to the flow in the slow reaction zone. We have termed this formulation flow integrated detonation shock dynamics (FIDSD). The purpose of the present paper is to show how the FIDSD formulation can be applied to detonation propagation on an Eulerian grid using an algorithm based on level set interface tracking and a ghost fluid approach.

Short, Mark [Los Alamos National Laboratory; Aslam, Tariq D [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

462

Pulsatile flow and heat transfer of a magneto-micropolar fluid through a stenosed artery under the influence of body acceleration  

E-Print Network [OSTI]

With an aim to investigate the effect of externally imposed body acceleration and magnetic field on pulsatile flow of blood through an arterial segment having stenosis is under consideration in this paper. The flow of blood is presented by a unsteady micropolar fluid and the heat transfer characteristics have been taken into account. The non-linear equations that governing the flow are solved numerically using finite difference technique by employing a suitable coordinate transformation. The numerical results have been observed for axial and microrotation component of velocity, fluid acceleration, wall shear stress(WSS), flow resistance, temperature and the volumetric flow rate. It thus turns out that the rate of heat transfer increases with the increase of Hartmann number $H$, while the wall shear stress has a reducing effect on the Hartmann number $H$ and an enhancing effect on microrotation parameter $K$ as well as the constriction height $\\delta$.

Shit, G C

2012-01-01T23:59:59.000Z

463

UNSAT-H Version 3.0: Unsaturated Soil Water and Heat Flow Model Theory, User Manual, and Examples  

SciTech Connect (OSTI)

The UNSAT-H model was developed at Pacific Northwest National Laboratory (PNNL) to assess the water dynamics of arid sites and, in particular, estimate recharge fluxes for scenarios pertinent to waste disposal facilities. During the last 4 years, the UNSAT-H model received support from the Immobilized Waste Program (IWP) of the Hanford Site's River Protection Project. This program is designing and assessing the performance of on-site disposal facilities to receive radioactive wastes that are currently stored in single- and double-shell tanks at the Hanford Site (LMHC 1999). The IWP is interested in estimates of recharge rates for current conditions and long-term scenarios involving the vadose zone disposal of tank wastes. Simulation modeling with UNSAT-H is one of the methods being used to provide those estimates (e.g., Rockhold et al. 1995; Fayer et al. 1999). To achieve the above goals for assessing water dynamics and estimating recharge rates, the UNSAT-H model addresses soil water infiltration, redistribution, evaporation, plant transpiration, deep drainage, and soil heat flow as one-dimensional processes. The UNSAT-H model simulates liquid water flow using Richards' equation (Richards 1931), water vapor diffusion using Fick's law, and sensible heat flow using the Fourier equation. This report documents UNSAT-H .Version 3.0. The report includes the bases for the conceptual model and its numerical implementation, benchmark test cases, example simulations involving layered soils and plants, and the code manual. Version 3.0 is an, enhanced-capability update of UNSAT-H Version 2.0 (Fayer and Jones 1990). New features include hysteresis, an iterative solution of head and temperature, an energy balance check, the modified Picard solution technique, additional hydraulic functions, multiple-year simulation capability, and general enhancements.

MJ Fayer

2000-06-12T23:59:59.000Z

464

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

E-Print Network [OSTI]

of Fracture-Matrix Heat Transfer Jens T. Birkholzer andon the magnitude of heat transfer from the matrix, waterthe interface area for heat transfer between the matrix and

Birkholzer, Jens T.; Zhang, Yingqi

2005-01-01T23:59:59.000Z

465

Evaluation of high-temperature lubricants for low-heat rejection diesel engines. Interim report, October 1983-March 1988  

SciTech Connect (OSTI)

A single-cylinder diesel engine was modified to simulate a low-heat rejection (LHR) engine, and it was used to develop lubrication requirements for future Army LHR diesel engines. Several high-temperature lubricant (HTL) candidates were evaluated, and the simulated LHR engine discriminated HTL deposition performance over a range of engine cylinder wall temperatures (CWTs). Three HTLs were identified that had promising performance at CWTs of 600 deg F (316 deg C) while none were adequate at 650 deg F (343 deg C). Oil was collected and analyzed from the ring zone of the simulated LHR engine. Oil degradation was as much as 3.7 times more severe in the ring zone as compared to the oil sump. Preliminary oxidation and friction-wear bench tests were investigated. New and used oil analyses flow charts were developed, and analytical techniques to separate and identify HTL additives and base stocks were developed.

Frame, E.A.

1992-09-01T23:59:59.000Z

466

Piston-driven flow of highly concentrated suspensions Ralf B. Lukner and Roger T. Bonnecazea)  

E-Print Network [OSTI]

Piston-driven flow of highly concentrated suspensions Ralf B. Lukner and Roger T. Bonnecazea October 1998; final revision received 4 February 1999) Synopsis The piston-driven flow of highly concentrated suspensions 55% or 59% by volume solids of dense spheres was investigated as a function of piston

467

HEAT: High accuracy extrapolated ab initio thermochemistry. III. Additional improvements and overview.  

SciTech Connect (OSTI)

Effects of increased basis-set size as well as a correlated treatment of the diagonal Born-Oppenheimer approximation are studied within the context of the high-accuracy extrapolated ab initio thermochemistry (HEAT) theoretical model chemistry. It is found that the addition of these ostensible improvements does little to increase the overall accuracy of HEAT for the determination of molecular atomization energies. Fortuitous cancellation of high-level effects is shown to give the overall HEAT strategy an accuracy that is, in fact, higher than most of its individual components. In addition, the issue of core-valence electron correlation separation is explored; it is found that approximate additive treatments of the two effects have limitations that are significant in the realm of <1 kJ mol{sup -1} theoretical thermochemistry.

Harding, M. E.; Vazquez, J.; Ruscic, B.; Wilson, A. K.; Gauss, J.; Stanton, J. F.; Chemical Sciences and Engineering Division; Univ. t Mainz; The Univ. of Texas; Univ. of North Texas

2008-01-01T23:59:59.000Z

468

Transient fluid and heat flow modeling in coupled wellbore/reservoir systems  

E-Print Network [OSTI]

showing cleanup period.......................................................... 68 Figure 5.21 Geothermal gradient and sea water temperature profile............................. 68 Figure 5.22 Mimicking oil production rate input... into this category. 5 Miller (1980) developed one of the earliest transient wellbore simulators, which accounts for changes in geothermal-fluid energy while flowing up the wellbore. In this model, mass and momentum equations are combined...

Izgec, Bulent

2009-05-15T23:59:59.000Z

469

Steady and Transient Characteristics of Catalytic Flow Reverse Reactor Integrated with Central Heat Exchanger  

Science Journals Connector (OSTI)

Most projects among them employ thermal flow-reversal oxidizers. ... Methane is oxidized into CO2 and water, and its global warming potential is reduced by 87%. ... The regenerative combustion can achieve theoretically an autothermal run of system, even if methane in air is 0.2% v/v. ...

Sheng Wang; Diannan Gao; Shudong Wang

2014-07-28T23:59:59.000Z

470

Congestion control schemes for single and parallel TCP flows in high bandwidth-delay product networks  

E-Print Network [OSTI]

high-speed TCP proposals have been suggested to overcome the limited throughput achievable by single-flow TCP by modifying its congestion control mechanisms. In the meantime, users overcome the throughput limitations in high bandwidth-delay product...

Cho, Soohyun

2006-08-16T23:59:59.000Z

471

Heat shock, an exposure to high but sublethal temperature, protects cells, tissues and organisms from a subsequent  

E-Print Network [OSTI]

Heat shock, an exposure to high but sublethal temperature, protects cells, tissues and organisms that the induced thermoprotection acts via a natural cellular stress mechanism mediated by upregulation of heat, 1993; Feder and Hofmann, 1999). Considering the success of heat shock (hsp70 induction) in r