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Note: This page contains sample records for the topic "generate 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

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

2

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

3

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

4

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

5

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

6

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

7

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

8

Flameless heat generator  

SciTech Connect

A heating device generates heat by working a liquid in a closed container with a rotating stack of finely perforate square plates and recovering the heat from the thus heated liquid. In one embodiment a stack of a multiplicity of flat square plates radially offset one from another is rotated in an oil bath in a container under an inner perforate non-rotating cover over which is a similar non-rotating cover that is imperforate. The thermal energy developed through the mechanical working of the liquid is transferred to the main liquid bath and is then removed, as for example, by circulating air or a liquid around the outside of the container with the thus heated air or liquid being used to heat a house or the like.

Leary, C. L.; Leary, G. C.

1983-12-13T23:59:59.000Z

9

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

10

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

11

New tube bundle heat transfer correlations and flow regime maps for a Once Through Steam Generator  

E-Print Network (OSTI)

? hydraulic behavior of a, nuclear reactor coolant system. Therefore, extensive analytical and experimental research has been performed to investigate the thermal ? hydraulic behavior of the steam generators dur- ing operational and accident transients... light water reactor system transient analysis code for use in rule making, licensing audit calcula- tions, evaluation of operator guidelines, and as a basis for a, nuclear plant analyzer . The code is used extensively at the Idaho National Engineering...

Blanchat, Thomas Kevin

2012-06-07T23:59:59.000Z

12

Control system for fluid heated steam generator  

DOE Patents (OSTI)

A control system for controlling the location of the nucleate-boiling region in a fluid heated steam generator comprises means for measuring the temperature gradient (change in temperature per unit length) of the heating fluid along the steam generator; means for determining a control variable in accordance with a predetermined function of temperature gradients and for generating a control signal in response thereto; and means for adjusting the feedwater flow rate in accordance with the control signal.

Boland, J.F.; Koenig, J.F.

1984-05-29T23:59:59.000Z

13

Heat and mass transfer of a viscous heat generating fluid with Hall currents  

Science Journals Connector (OSTI)

A study of natural convection in hydrodynamic flows of a viscous heat generating fluid in the presence of Hall currents and ... out. The governing equations for the magnetohydrodynamic fluid flow and heat transfer

P. C. Ram; S. S. Singh; R. K. Jain

14

Skutterudite Thermoelectric Generator For Automotive Waste Heat...  

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

Skutterudite Thermoelectric Generator For Automotive Waste Heat Recovery Skutterudite Thermoelectric Generator For Automotive Waste Heat Recovery Skutterudite TE modules were...

15

Waste Heat Recovery Opportunities for Thermoelectric Generators...  

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

Waste Heat Recovery Opportunities for Thermoelectric Generators Waste Heat Recovery Opportunities for Thermoelectric Generators Thermoelectrics have unique advantages for...

16

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

17

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

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

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

18

Distributed Generation with Heat Recovery and Storage  

E-Print Network (OSTI)

Energy; Grid systems; Optimization; Heat flow; Financialof grid power and by utilizing combined heat and power (CHP)

Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

2008-01-01T23:59:59.000Z

19

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,...

20

Heat Recovery Steam Generator Simulation  

E-Print Network (OSTI)

The paper discusses the applications of Heat Recovery Steam Generator Simulation. Consultants, plant engineers and plant developers can evaluate the steam side performance of HRSGs and arrive at the optimum system which matches the needs...

Ganapathy, V.

Note: This page contains sample records for the topic "generate 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

Distributed Generation with Heat Recovery and Storage  

E-Print Network (OSTI)

of fossil fuel sources of waste heat and other lossesthat this is only the waste heat from fossil generation,an estimate of the total waste heat from fossil generation

Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

2008-01-01T23:59:59.000Z

22

Distributed Generation with Heat Recovery and Storage  

E-Print Network (OSTI)

selection of on-site power generation with combined heat andTotal Electricity Generation Figure 13. Small MercantileWeekday Total Electricity Generation (No Storage Adoption

Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

2008-01-01T23:59:59.000Z

23

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...

24

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

25

Heat Transfer Enhancement in Thermoelectric Power Generation.  

E-Print Network (OSTI)

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

Hu, Shih-yung

2009-01-01T23:59:59.000Z

26

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

27

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 őľcal/gm-yr, which is slightly

28

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...

29

Distributed Generation with Heat Recovery and Storage  

E-Print Network (OSTI)

power generation with combined heat and power applications,Ēof carbon tax on combined heat and power adoption by a131(1), 2-25. US Combined Heat and Power Association (

Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

2008-01-01T23:59:59.000Z

30

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. VinokurovÖ

1978-01-01T23:59:59.000Z

31

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

32

Heat engine generator control system  

DOE Patents (OSTI)

An electrical power generation system includes a heat engine having an output member operatively coupled to the rotor of a dynamoelectric machine. System output power is controlled by varying an electrical parameter of the dynamoelectric machine. A power request signal is related to an engine speed and the electrical parameter is varied in accordance with a speed control loop. Initially, the sense of change in the electrical parameter in response to a change in the power request signal is opposite that required to effectuate a steady state output power consistent with the power request signal. Thereafter, the electrical parameter is varied to converge the output member speed to the speed known to be associated with the desired electrical output power.

Rajashekara, Kaushik (Carmel, IN); Gorti, Bhanuprasad Venkata (Towson, MD); McMullen, Steven Robert (Anderson, IN); Raibert, Robert Joseph (Fishers, IN)

1998-01-01T23:59:59.000Z

33

Heat engine generator control system  

DOE Patents (OSTI)

An electrical power generation system includes a heat engine having an output member operatively coupled to the rotor of a dynamoelectric machine. System output power is controlled by varying an electrical parameter of the dynamoelectric machine. A power request signal is related to an engine speed and the electrical parameter is varied in accordance with a speed control loop. Initially, the sense of change in the electrical parameter in response to a change in the power request signal is opposite that required to effectuate a steady state output power consistent with the power request signal. Thereafter, the electrical parameter is varied to converge the output member speed to the speed known to be associated with the desired electrical output power. 8 figs.

Rajashekara, K.; Gorti, B.V.; McMullen, S.R.; Raibert, R.J.

1998-05-12T23:59:59.000Z

34

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

35

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 analysisÖ (more)

Meholic, Michael

2011-01-01T23:59:59.000Z

36

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

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

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

37

Waste Heat Recovery Power Generation with WOWGen  

E-Print Network (OSTI)

Waste Heat Recovery Power Generation with WOWGen? Business Overview WOW operates in the energy efficiency field - one of the fastest growing energy sectors in the world today. The two key products - WOWGen? and WOWClean? provide more... energy at cheaper cost and lower emissions. ? WOWGen? - Power Generation from Industrial Waste Heat ? WOWClean? - Multi Pollutant emission control system Current power generation technology uses only 35% of the energy in a fossil fuel...

Romero, M.

38

Nuclear power eyed to generate industrial heat  

Science Journals Connector (OSTI)

Nuclear power eyed to generate industrial heat ... The American Nuclear Society has called for "an aggresssive national policy aimed at demonstrating specific capabilities and providing incentives for the application of nuclear power to meeting industrial energy needs." ...

1983-10-24T23:59:59.000Z

39

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

40

Corner heating in rectangular solid oxide electrochemical cell generators  

DOE Patents (OSTI)

Disclosed is an improvement in a solid oxide electrochemical cell generator 1 having a rectangular design with four sides that meet at corners, and containing multiplicity of electrically connected fuel cells 11, where a fuel gas is passed over one side of said cells and an oxygen containing gas is passed into said cells, and said fuel is burned to form heat, electricity, and an exhaust gas. The improvement comprises passing the exhaust gases over the multiplicity of cells 11 in such a way that more of the heat in said exhaust gases flows at the corners of the generator, such as through channels 19.

Reichner, Philip (Plum Boro, PA)

1989-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "generate 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

Constructal multi-scale package of vertical channels with natural convection and maximal heat transfer density. CONSTRUCTAL DESIGN: THE GENERATION OF MULTI-SCALE HEAT  

E-Print Network (OSTI)

transfer density. CONSTRUCTAL DESIGN: THE GENERATION OF MULTI-SCALE HEAT AND FLUID FLOW STRUCTURES-scale structures in natural convection with the objective of maximizing the heat transfer density, or the heat transfer rate per unit of volume§ . The flow volume is filled with vertical equidistant heated blades

Kihm, IconKenneth David

42

Heat Transfer Enhancement: Second Generation Technology  

E-Print Network (OSTI)

stant temperature difference or one-ninth the temp erature difference at a constant heat flux compared to plain tubes. 7.5 frn/em lin tube Atter flanening ltn tips Some manufacturers also employ tube-side en hancement for water flowing...

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

1984-01-01T23:59:59.000Z

43

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

SciTech Connect

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

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

2002-08-01T23:59:59.000Z

44

Cryogenic heat exchanger with turbulent flows  

Science Journals Connector (OSTI)

An evaporator-type cryogenic heat exchanger is designed and built for introducing fluidĖsolid 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 NuĖRe 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; Gťrard Defresne

2012-01-01T23:59:59.000Z

45

Joule heating generated by spin current through Josephson junctions  

SciTech Connect

We theoretically study the spin-polarized current flowing through a Josephson junction (JJ) in a spin injection device. When the spin-polarized current is injected from a ferromagnet in a superconductor (SC), the charge current is carried by the superconducting condensate (Cooper pairs), while the spin-up and spin-down currents flow in equal magnitude but in the opposite direction in a SC, because of no quasiparticle charge current in the SC. This indicates that not only the Josephson current but also the spin current flow across JJ at zero bias voltage, thereby generating Joule heating by the spin current. The result provides a new method for detecting the spin current by measuring Joule heating at JJ. {copyright} 2001 American Institute of Physics.

Takahashi, S.; Yamashita, T.; Koyama, T.; Maekawa, S.; Imamura, H.

2001-06-01T23:59:59.000Z

46

Generator powered electrically heated diesel particulate filter  

DOE Patents (OSTI)

A control circuit for a vehicle powertrain includes a switch that selectivity interrupts current flow between a first terminal and a second terminal. A first power source provides power to the first terminal and a second power source provides power to the second terminal and to a heater of a heated diesel particulate filter (DPF). The switch is opened during a DPF regeneration cycle to prevent the first power source from being loaded by the heater while the heater is energized.

Gonze, Eugene V; Paratore, Jr., Michael J

2014-03-18T23:59:59.000Z

47

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

48

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

49

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.

50

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

51

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...

52

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. BOLDIZSŃR

1964-06-27T23:59:59.000Z

53

Radio frequency (RF) heated supersonic flow laboratory  

SciTech Connect

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

54

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

55

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

56

.Heat Generation Patterns and Temperature Profiles in_ Electroslag Welding  

E-Print Network (OSTI)

l .Heat Generation Patterns and Temperature Profiles in_ Electroslag Welding ) · T. DEBROY, J process parameters such as the voltage profiles, heat generation patterns and temperature profiles with equivalent slag, electrode and other geometrical variable; Calcu- 0 lations show that the heat generation

Eagar, Thomas W.

57

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

58

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

59

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

60

Property:Distributed Generation System Heating-Cooling Application | Open  

Open Energy Info (EERE)

Heating-Cooling Application Heating-Cooling Application Jump to: navigation, search This is a property of type Page. Pages using the property "Distributed Generation System Heating-Cooling Application" Showing 21 pages using this property. D Distributed Generation Study/10 West 66th Street Corp + Domestic Hot Water +, Space Heat and/or Cooling + Distributed Generation Study/Aisin Seiki G60 at Hooligans Bar and Grille + Domestic Hot Water + Distributed Generation Study/Arrow Linen + Domestic Hot Water + Distributed Generation Study/Dakota Station (Minnegasco) + Space Heat and/or Cooling +, Other + Distributed Generation Study/Elgin Community College + Space Heat and/or Cooling +, Domestic Hot Water + Distributed Generation Study/Emerling Farm + Domestic Hot Water +, Process Heat and/or Cooling +

Note: This page contains sample records for the topic "generate 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

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

62

FINAL STAFF PAPER A New Generation of Combined Heat  

E-Print Network (OSTI)

onsite or exporting it to the grid. The feasibility of meeting the state's combined heat and power goals FINAL STAFF PAPER A New Generation of Combined Heat and Power: Policy Planning. Neff , Bryan. A New Generation of Combined Heat and Power: Policy Planning for 2030. 2012. California

63

Heat flow in the postquasistatic approximation  

SciTech Connect

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

64

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. RodrŪguez-Mueller; C. Peralta; W. Barreto; L. Rosales

2010-05-10T23:59:59.000Z

65

Waste Heat Recovery Opportunities for Thermoelectric Generators  

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

Thermoelectrics have unique advantages for integration into selected waste heat recovery applications.

66

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

67

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...

68

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...

69

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

70

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...

71

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

72

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

73

Heat transfer research on supercritical water flow upward in tube  

SciTech Connect

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

74

Magnetohydrodynamic power generation, electromagnetic pumps, heat pipes, and thermionic convertors  

SciTech Connect

The basic principles of operation, components, and design of MHD generators, electromagnetic pumps, heat pipes and thermionic converters are described. 66 references. (WHK)

Pierson, E.S.; Bonyhady, K.A.; Dunn, P.F.; Nathenson, R.D.; Uherka, K.L.

1984-01-01T23:59:59.000Z

75

Method of calculation of heat generation rates for DWPF glass  

SciTech Connect

The Waste Acceptance Preliminary Specifications (WAPS) require estimates of the heat generation rate of DWPF waste glasses. Estimates of the heat generation rates of projected glass compositions are to be reported in the Waste Form Qualification Report. Similar estimates for actual production glasses are to be reported in the Production Records. In this report, a method of calculating the heat generation rate from the radionuclide inventory is provided. Application of the method to the DWPF Design-Basis glass indicates that the heat generation rate can be accurately estimated from the Sr-90, Y-90, Cs-137, Ba-137m, and Pu-238 contents alone.

Plodinec, M.J.

1992-03-17T23:59:59.000Z

76

Method of calculation of heat generation rates for DWPF glass  

SciTech Connect

The Waste Acceptance Preliminary Specifications (WAPS) require estimates of the heat generation rate of DWPF waste glasses. Estimates of the heat generation rates of projected glass compositions are to be reported in the Waste Form Qualification Report. Similar estimates for actual production glasses are to be reported in the Production Records. In this report, a method of calculating the heat generation rate from the radionuclide inventory is provided. Application of the method to the DWPF Design-Basis glass indicates that the heat generation rate can be accurately estimated from the Sr-90, Y-90, Cs-137, Ba-137m, and Pu-238 contents alone.

Plodinec, M.J.

1993-02-04T23:59:59.000Z

77

NREL: Vehicle Ancillary Loads Reduction - Heat Generated Cooling  

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

Heat Generated Cooling Heat Generated Cooling A counterintuitive but promising path to reducing the loads imposed by automotive air conditioning systems is to use heat-specifically the waste heat generated by engines. This can be an abundant source of energy, since most light-duty vehicles with combustion engines are only about 30% efficient at best. With that degree of thermal efficiency, an engine releases 70% of its fuel energy as waste heat through the coolant, exhaust gases, and engine compartment warm-up. During much of a typical drive cycle, the engine efficiency is even lower than 30%. As efficiency decreases, the amount of waste heat increases, representing a larger potential energy source. NREL's Vehicle Ancillary Loads Reduction (VALR) team is investigating a number of heat generated cooling technologies

78

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

79

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; …. L. Spektor

1971-01-01T23:59:59.000Z

80

Why Blow Away Heat? Harvest Server's Heat Using Ther-moelectric Generators  

E-Print Network (OSTI)

Why Blow Away Heat? Harvest Server's Heat Using Ther- moelectric Generators Ted Tsung-Te Lai, Wei ABSTRACT This paper argues for harvesting energy from servers' wasted heat in data centers. Our approach is to distribute a large number of thermoelectric generators (TEGs) on or nearby server hotspot components whose

Huang, Polly

Note: This page contains sample records for the topic "generate 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

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

82

Issues in heat recovery steam generator system noise  

Science Journals Connector (OSTI)

A heat recovery steam generator (HRSG) is a fundamental component of all combustion turbine?based combined cycle power plants. While itís primary purpose is to convert exhaust gas heat to steam an important secondary function is to reduce noise emissions from the combustion turbine exhaust. This source at about 155 dB (overall) re: 1 pW for a 100?MW turbine is the highest noise emission source in any combustion turbine plant. Therefore the residual exhaust noise emissions leaving the HRSG walls and stack exit must be predicted with acceptable accuracy to determine the total plant noise level. The sources involved in this prediction methodology will be discussed. The issues include source power levels wall and duct transmission loss and the noise reduction characteristics through the HRSG flow path. Special measurement techniques required to quantify HRSG noise emissions are described. Whereas the HRSG is mainly a passive device that attenuates combustion turbine exhaust noise two HRSG generated sources steam venting and supplemental duct firing will also be discussed. [See NOISE?CON Proceedings for full paper.

George F. Hessler Jr.

1997-01-01T23:59:59.000Z

83

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

84

3D THERMOGRAPHY FOR QUANTIFICATION OF HEAT GENERATION RESULTING FROM  

E-Print Network (OSTI)

been used for decades by biologists and clinicians to isolate main sites of body heat loss by biologists and clinicians to isolate main sites of body heat loss and to assist with diagnosis3D THERMOGRAPHY FOR QUANTIFICATION OF HEAT GENERATION RESULTING FROM INFLAMMATION THERMOGRAPHIE 3D

Nebel, Jean-Christophe

85

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...

86

Thermionic generator module with heat pipes  

SciTech Connect

A thermionic converter module is described comprising: a first heat pipe with an annular casing which has a first surface located on an inside surface of the annular casing, at least part of the first surface of the casing of the first heat pipe having constructed upon it a thermionic converter emitter located so that heat will be transferred by conduction from the first heat pipe casing to the thermionic converter emitter; a second heat pipe with a casing which has a second surface, the second surface being located within the first surface of the annular casing of the first heat pipe so that it is surrounded by the first surface; a thermionic converter collector located so as to transfer heat by conduction to the second surface of the casing of the second heat pipe with the thermionic converter collector being adjacent to the thermionic converter emitter but being separated from the thermionic converter emitter by an inter electrode space; and end fitting structures located so that, with the thermionic converter collector and the thermionic converter emitter, they complete an enclosure around the inter electrode space and form an evacuated enclosure within which are located the thermionic converter collector and the thermionic converter emitter.

Horner-Richardson, K.; Ernst, D.M.

1993-06-15T23:59:59.000Z

87

Heat transfer in a thermoelectric generator for diesel engines  

SciTech Connect

This paper discusses the design and test results obtained for a 1kW thermoelectric generator used to convert the waste thermal energy in the exhaust of a Diesel engine directly to electric energy. The paper focuses on the heat transfer within the generator and shows what had to be done to overcome the heat transfer problems encountered in the initial generator testing to achieve the output goal of 1kW electrical. The 1kW generator uses Bismuth-Telluride thermoelectric modules for the energy conversion process. These modules are also being evaluated for other waste heat applications. Some of these applications are briefly addressed.

Bass, J.C. [Hi-Z Technology, Inc., San Diego, CA (United States)

1995-12-31T23:59:59.000Z

88

A new absorption chiller to establish combined cold, heat, and power generation utilizing low-temperature heat  

SciTech Connect

Presently available absorption machines for air conditioning are driven with heat of a minimum of 80 C (176 F). A combination of the standard single-effect and a double-lift process has been identified as a new cycle that can use driving heat down to return temperatures of about 55 C (131 F) and permits temperature glides in generation of more than 30 K (54 F). Thus a larger cooling capacity can be produced from the same heat source compared to a single-effect chiller run with the same heat carrier supply temperature and mass flow. According to the estimated heat exchanger area, competitive machine costs for this new chiller can be expected. This single-effect/double-lift absorption chiller can be operated with waste heat from industrial processes, as well as with low-temperature heat (e.g., heat from solar collectors) as driving heat for air conditioning. The large temperature glide and the low return temperature especially fit the operating conditions in district heating networks during the summer. The cycle will be presented, followed by a discussion of suitable operating conditions.

Schweigler, C.J.; Riesch, P.; Demmel, S.; Alefeld, G. [ZAE Bayern, Garching/Muenchen (Germany)

1996-11-01T23:59:59.000Z

89

MHTGR steam generator on-line heat balance, instrumentation and function  

SciTech Connect

Instrumentation is used to measure the Modular High Temperature Gas-Cooled Reactor (MHTGR) steam generator dissimilar metal weld temperature during start-up testing. Additional instrumentation is used to determine an on-line heat balance which is maintained during the 40 year module life. In the process of calibrating the on-line heat balance, the helium flow is adjusted to yield the optimum boiling level in the steam generator relative to the dissimilar metal weld. After calibration is complete the weld temperature measurement is non longer required. The reduced boiling level range results in less restrictive steam generator design constraints.

Klapka, R.E.; Howard, W.W.; Etzel, K.T. (General Atomics, San Diego, CA (United States)); Basol, M.; Karim, N.U. (ABB-CENP, Chattanooga, TN (United States))

1991-09-01T23:59:59.000Z

90

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

91

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

SciTech Connect

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

92

Heat flow and geothermal studies in the Great Plains  

SciTech Connect

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

93

Distributed Generation with Heat Recovery and Storage  

E-Print Network (OSTI)

most commercial buildings, electricity costs far exceed heatoffset by lower electricity costs from on- site generation (as much from lower electricity costs as it does from lower

Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

2008-01-01T23:59:59.000Z

94

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 ¬Ľ 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

95

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

96

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...

97

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

98

Field application of a chemical heat and nitrogen generating system  

SciTech Connect

Heat is often required to stimulate production in wells with recurrent histories of paraffin deposition and plugging. A chemical system which produces heat and nitrogen at a predetermined well depth is proposed as an alternative to the traditional hot oil and steam generation treatments. The system is described briefly and case histories are given for 3 wells in California and 5 wells in Wyoming. The field results indicate that heat produced by the nitrogen generating system effectively stimulates production from paraffin plugged wells. The heat and nitrogen generating system further shows increased production cycle lengths over those which result from hot oil or paraffin solvent treatments. Beneficial effects of including a paraffin inhibitor in the treatment design are discussed, along with other potential applications for the heat produced by this system.

Mitchell, T.I.; Collesi, J.B.; Donovan, S.C.; McSpadden, H.W.

1984-04-01T23:59:59.000Z

99

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

100

Power Generation From Waste Heat Using Organic Rankine Cycle Systems  

E-Print Network (OSTI)

Many efforts are currently being pursued to develop and implement new energy technologies aimed at meeting our national energy goals The use of organic Rankine cycle engines to generate power from waste heat provides a near term means to greatly...

Prasad, A.

1980-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "generate 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

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

102

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

103

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

104

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

SciTech Connect

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

105

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

106

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part II: Parametric Evaluation  

E-Print Network (OSTI)

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part II: Parametric Evaluation been proposed to model thermoelectric generators (TEGs) for automotive waste heat recovery. Details: Thermoelectric generators, waste heat recovery, automotive exhaust, skutterudites INTRODUCTION In part I

Xu, Xianfan

107

Finned Tube With Vortex Generators For A Heat Exchanger.  

DOE Patents (OSTI)

A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

Sohal, Monohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

2004-09-14T23:59:59.000Z

108

Billet Heating with the Homopolar Generator  

E-Print Network (OSTI)

energy storage using homopolar electro mechanical conversion is the least expensive and most compact among the practical methods of energy storage which would allow energy to be drawn from the utility grid in a continuous mode, including loading... a conductor that moves through a unidirection al magnetic field. The essential difference from a conventional generator is that the current travels through the rotor itself which is the energy storage flywheel and makes only one transit across...

Weldon, W. F.; Keith, R. E.; Weldon, J. M.

1980-01-01T23:59:59.000Z

109

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

110

An improved absorption generator for solar-thermal powered heat pumps. Part 1: Feasibility  

SciTech Connect

Solar heated absorption chiller installations have been, typically, very expensive for their rating. The need to keep the liquid flowing within the collectors as cool as possible to enhance collector thermal efficiency, conflicts with the need to operate the absorption chiller at a higher temperature. The compromise usually results in poor collector efficiency as well as a relatively poor specific chiller effect. The proposed vortex generator permits a heat pump to operate efficiently with relatively low temperature solar heated fluid (70--80 C). As a result, the collectors are cooler and much more efficient. In addition, the specific heat pumping capacity is about 27% greater than conventional systems operating at the same reduced generator temperatures and, therefore, a smaller chiller is required. The economic consequences of these benefits will be presented in Part 2.

Fineblum, S. [Megadyne Inc., Rochester, NY (United States)

1997-12-31T23:59:59.000Z

111

An improved absorption generator for solar-thermal powered heat pumps. Part 2: Energy and economics  

SciTech Connect

Solar heated absorption chiller installations have been very expensive for their rating. To enhance collector thermal efficiency the liquid flowing within the collectors must be kept as cool as possible. However, there is also a need to operate the absorption reported earlier. The compromise usually results in poor collector efficiency as well as a relatively poor specific chiller effect. The proposed vortex generator permits a heat pump to operate efficiently with relatively low temperature solar heated fluid (70--80 C). As a result, the collectors are cooler and more efficient. As noted in Part 1, the specific heat pumping capacity is about 27% greater than conventional systems operating at the same reduced generator temperatures. Therefore, a smaller, less expensive chiller is required. The reduced investment in solar arrays and absorption chillers is estimated along with a range of paybacks.

Fineblum, S. [Megadyne Inc., Rochester, NY (United States)

1997-12-31T23:59:59.000Z

112

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

SciTech Connect

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

113

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

114

Brine flow in heated geologic salt.  

SciTech Connect

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

115

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,

116

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

117

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 Mškilš; Markku Lampinen; Risto Lahdelma

2014-01-01T23:59:59.000Z

118

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

119

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 exponentiallyÖ (more)

Foong, Andrew Jun Li

2009-01-01T23:59:59.000Z

120

New geothermal heat extraction process to deliver clean power generation  

ScienceCinema (OSTI)

A new method for capturing significantly more heat from low-temperature geothermal resources holds promise for generating virtually pollution-free electrical energy. Scientists at the Department of Energys Pacific Northwest National Laboratory will determine if their innovative approach can safely and economically extract and convert heat from vast untapped geothermal resources. The goal is to enable power generation from low-temperature geothermal resources at an economical cost. In addition to being a clean energy source without any greenhouse gas emissions, geothermal is also a steady and dependable source of power.

Pete McGrail

2012-12-31T23:59:59.000Z

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121

Techno-economic analysis of using corn stover to supply heat and power to a corn ethanol plant - Part 2: Cost of heat and power generation systems  

SciTech Connect

This paper presents a techno-economic analysis of corn stover fired process heating (PH) and the combined heat and power (CHP) generation systems for a typical corn ethanol plant (ethanol production capacity of 170 dam3). Discounted cash flow method was used to estimate both the capital and operating costs of each system and compared with the existing natural gas fired heating system. Environmental impact assessment of using corn stover, coal and natural gas in the heat and/or power generation systems was also evaluated. Coal fired process heating (PH) system had the lowest annual operating cost due to the low fuel cost, but had the highest environmental and human toxicity impacts. The proposed combined heat and power (CHP) generation system required about 137 Gg of corn stover to generate 9.5 MW of electricity and 52.3 MW of process heat with an overall CHP efficiency of 83.3%. Stover fired CHP system would generate an annual savings of 3.6 M$ with an payback period of 6 y. Economics of the coal fired CHP system was very attractive compared to the stover fired CHP system due to lower fuel cost. But the greenhouse gas emissions per Mg of fuel for the coal fired CHP system was 32 times higher than that of stover fired CHP system. Corn stover fired heat and power generation system for a corn ethanol plant can improve the net energy balance and add environmental benefits to the corn to ethanol biorefinery.

Mani, Sudhagar [University of Georgia; Sokhansanj, Shahabaddine [ORNL; Togore, Sam [U.S. Department of Energy; Turhollow Jr, Anthony F [ORNL

2010-03-01T23:59:59.000Z

122

Coupled flow and heat transfer in viscoelastic fluid with CattaneoĖChristov 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 Fourierís Law and the CattaneoĖChristov heat flux model is also presented.

Shihao Han; Liancun Zheng; Chunrui Li; Xinxin Zhang

2014-01-01T23:59:59.000Z

123

Friction-Induced Fluid Heating in Nanoscale Helium Flows  

SciTech Connect

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

124

Determination of a flow generating a neutral magnetic mode  

E-Print Network (OSTI)

The problem of reconstruction of a flow of conducting incompressible fluid generating a given magnetic mode is considered. We use the magnetic induction equation to derive ordinary differential equations along the magnetic field lines, which give an opportunity to determine the generating flow, if additional data is provided on a two-dimensional manifold transversal to magnetic field lines, and show that an arbitrary solenoidal vector field can not be a neutral magnetic mode sustained by any flow of conducting fluid.

V. Zheligovsky

2009-06-30T23:59:59.000Z

125

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

SciTech Connect

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

126

Multi-physics modeling of thermoelectric generators for waste heat recovery applications  

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

Model developed provides effective guidelines to designing thermoelectric generation systems for automotive waste heat recovery applications

127

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling  

E-Print Network (OSTI)

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling telluride TEMs. Key words: Thermoelectric generators, waste heat recovery, automotive exhaust, skutterudites bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from

Xu, Xianfan

128

Development of Design Criteria for Fluid Induced Structural Vibration in Steam Generators and Heat Exchangers  

SciTech Connect

OAK-B135 Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers. In the nuclear industry, steam generators are often affected by this problem. However, flow-induced vibration is not limited to nuclear power plants, but to any type of heat exchanger used in many industrial applications such as chemical processing, refrigeration and air conditioning. Specifically, shell and tube type heat exchangers experience flow-induced vibration due to the high velocity flow over the tube banks. Flow-induced vibration in these heat exchangers leads to equipment breakdown and hence expensive repair and process shutdown. The goal of this research is to provide accurate measurements that can help modelers to validate their models using the measured experimental parameters and thereby develop better design criteria for avoiding fluid-elastic instability in heat exchangers. The research is divided between two primary experimental efforts, the first conducted using water alone (single phase) and the second using a mixture of air or steam and water as the working fluid (two phase). The outline of this report is as follows: After the introduction to fluid-elastic instability, the experimental apparatus constructed to conduct the experiments is described in Chapter 2 along with the measurement procedures. Chapter 3 presents results obtained on the tube array and the flow loop, as well as techniques used in data processing. The project performance is described and evaluated in Chapter 4 followed by a discussion of publications and presentations relevant to the project in Chapter 5, while the conclusions and recommendations for future work are presented in Chapter 6.

Catton, Ivan; Dhir, Vijay K.; Alquaddoomi, O.S.; Mitra, Deepanjan; Adinolfi, Pierangelo

2004-03-26T23:59:59.000Z

129

Flow-induced vibration of component cooling water heat exchangers  

SciTech Connect

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

130

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. SÝgaard; Olafur P. Palsson

1994-01-01T23:59:59.000Z

131

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

132

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.

133

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 inÖ (more)

Dai, Zhenhui

2014-01-01T23:59:59.000Z

134

COMPUTATION OF TWO-PHASE FLOW IN STEAM GENERATOR  

E-Print Network (OSTI)

COMPUTATION OF TWO-PHASE FLOW IN STEAM GENERATOR USING DOMAIN DECOMPOSITION AND LOCAL ZOOM METHODS Abstract We present ow simulations in the Steam Generator of a pressurized water nuclear reactor using coherence between the zoom and the full domain. Key words: Steam Generator, Zoom, Domain Decomposition

Paris-Sud XI, Université de

135

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

136

Flow and heat transfer around a linear array of spheres  

SciTech Connect

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

137

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 flowÖ (more)

Jones, Michael S

2003-01-01T23:59:59.000Z

138

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

139

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 QinÖ

2012-04-01T23:59:59.000Z

140

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...=0Ė16†kV) are investigated in detail...

Chia-Wen Lin; Jiin-Yuh Jang

2005-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "generate 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

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

142

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

143

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

144

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.

145

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

146

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

147

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

148

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

149

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

150

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

151

Generating Geodesic Flows and Supergravity Solutions  

E-Print Network (OSTI)

We consider the geodesic motion on the symmetric moduli spaces that arise after timelike and spacelike reductions of supergravity theories. The geodesics correspond to timelike respectively spacelike $p$-brane solutions when they are lifted over a $p$-dimensional flat space. In particular, we consider the problem of constructing \\emph{the minimal generating solution}: A geodesic with the minimal number of free parameters such that all other geodesics are generated through isometries. We give an intrinsic characterization of this solution in a wide class of orbits for various supergravities in different dimensions. We apply our method to three cases: (i) Einstein vacuum solutions, (ii) extreme and non-extreme D=4 black holes in N=8 supergravity and their relation to N=2 STU black holes and (iii) Euclidean wormholes in $D\\geq 3$. In case (iii) we present an easy and general criterium for the existence of regular wormholes for a given scalar coset.

E. Bergshoeff; W. Chemissany; A. Ploegh; M. Trigiante; T. Van Riet

2008-10-30T23:59:59.000Z

152

EXERGY ANALYSIS AND ENTROPY GENERATION MINIMIZATION OF THERMOELECTRIC WASTE HEAT RECOVERY FOR ELECTRONICS  

E-Print Network (OSTI)

Energy recovery from waste heat is attracting more and more attention. All electronic systems consume electricity but only a fraction of it is used for information processing and for human interfaces, such as displays. Lots of energy is dissipated as heat. There are some discussions on waste heat recovery from the electronic systems such as laptop computers. However the efficiency of energy conversion for such utilization is not very attractive due to the maximum allowable temperature of the heat source devices. This leads to very low limits of Carnot efficiency. In contrast to thermodynamic heat engines, Brayton cycle, free piston Stirling engines, etc., authors previously reported that thermoelectric (TE) can be a cost-effective device if the TE and the heat sink are co-optimized, and if some parasitic effects could be reduced. Since the heat already exists and it is free, the additional cost and energy payback time are the key measures to evaluate the value of the energy recovery system. In this report, we will start with the optimum model of the TE power generation system. Then, theoretical maximum output, cost impact and energy payback are evaluated in the examples of electronics system. Entropy Generation Minimization (EGM) is a method already familiar in thermal management of electronics. The optimum thermoelectric waste heat recovery design is compared with the EGM approach. Exergy analysis evaluates the useful energy flow in the optimum TE system. This comprehensive analysis is used to predict the potential future impact of the TE material development, as the dimensionless figure-ofmerit (ZT) is improved.

Kazuaki Yazawa; Ali Shakouri

153

Neoclassical generation of toroidal zonal flow by drift wave turbulence  

SciTech Connect

Zonal-flow instabilities due to drift-wave turbulence in the presence of toroidicity-induced parallel (neoclassical) viscosity and allowing for the toroidal flow are studied. It is shown that, as a result of the neoclassical viscosity a new type of zonal-flow instability is possible, leading to the generation of the considerable toroidal zonal flow. The toroidal instability is complementary to the previously studied instability resulting in the poloidal flow generation and occurs as a second branch of the general dispersion relation describing the evolution of the poloidal and toroidal flow. Nonlinear saturation of the new instability is studied. It is shown that saturated zonal toroidal velocity, generated in this instability, is large compared to the mean cross-field drift velocity as the ratio q/{epsilon}, where q is the safety factor and {epsilon} is the inverse aspect ratio. In addition to the broad turbulent spectrum of drift waves, a monochromatic wave packet is considered. It is revealed that for the case of sufficiently strong neoclassical viscosity such a wave packet is subjected to generation of the toroidal zonal flow due to instability of hydrodynamic type.

Mikhailovskii, A.B.; Smolyakov, A.I.; Tsypin, V.S.; Kovalishen, E.A.; Shirokov, M.S.; Galvao, R.M.O. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation); University of Saskatchewan, 116 Science place, Saskatoon S7N 5E2 (Canada) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil); Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Moscow Engineering Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil) and Brazilian Center for Research in Physics, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil)

2006-03-15T23:59:59.000Z

154

Economizer recirculation for low-load stability in heat recovery steam generator  

SciTech Connect

An economizer system is described for heating feedwater in a heat recovery steam generator which consists of: at least first and second economizer tube planes; each of the economizer tube planes including a plurality of generally parallel tubes; the tubes being generally vertically disposed; each of the economizer tube planes including a top header and a bottom header; all of the plurality of tubes in each economizer tube plane being connected in parallel to their top and bottom headers whereby parallel feedwater flow through the plurality of tubes between the top and bottom headers is enabled; one of the top and bottom headers being an inlet header; a second of the top and bottom headers being an outlet header; a boiler feed pump; the boiler feed pump being effective for applying a flow of feedwater to the inlet header; means for serially interconnecting the economizer tube planes; the means for serially interconnecting including means for flowing the feedwater upward and downward in tubes of alternating ones of the economizer tube planes between the inlet header and the outlet header; means for conveying heated feedwater from the outlet header to a using process; means for recirculating at least a portion of the heated feedwater from the outlet header to an inlet of the boiler feed pump; and the means for recirculating including means for relating the portion to a steam load in the using process whereby an increased flow is produced through all of the economizer tube planes at values of the steam load below a predetermined value and a condition permitting initiation of reverse flow in any of the tubes is substantially reduced.

Cuscino, R.T.; Shade, R.L. Jr.

1986-04-15T23:59:59.000Z

155

Generation of acoustic-gravity waves in ionospheric HF heating experiments : simulating large-scale natural heat sources  

E-Print Network (OSTI)

In this thesis, we investigate the potential role played by large-scale anomalous heat sources (e.g. prolonged heat wave events) in generating acoustic-gravity waves (AGWs) that might trigger widespread plasma turbulence ...

Pradipta, Rezy

2012-01-01T23:59:59.000Z

156

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

SciTech Connect

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

157

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.

158

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, Sťbastien; Shevchuk, Igor V; 10.1016/j.ijthermalsci.2012.11.009

2013-01-01T23:59:59.000Z

159

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

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

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

160

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

SciTech Connect

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

Note: This page contains sample records for the topic "generate 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

Salt disposal of heat-generating nuclear waste.  

SciTech Connect

This report summarizes the state of salt repository science, reviews many of the technical issues pertaining to disposal of heat-generating nuclear waste in salt, and proposes several avenues for future science-based activities to further the technical basis for disposal in salt. There are extensive salt formations in the forty-eight contiguous states, and many of them may be worthy of consideration for nuclear waste disposal. The United States has extensive experience in salt repository sciences, including an operating facility for disposal of transuranic wastes. The scientific background for salt disposal including laboratory and field tests at ambient and elevated temperature, principles of salt behavior, potential for fracture damage and its mitigation, seal systems, chemical conditions, advanced modeling capabilities and near-future developments, performance assessment processes, and international collaboration are all discussed. The discussion of salt disposal issues is brought current, including a summary of recent international workshops dedicated to high-level waste disposal in salt. Lessons learned from Sandia National Laboratories' experience on the Waste Isolation Pilot Plant and the Yucca Mountain Project as well as related salt experience with the Strategic Petroleum Reserve are applied in this assessment. Disposal of heat-generating nuclear waste in a suitable salt formation is attractive because the material is essentially impermeable, self-sealing, and thermally conductive. Conditions are chemically beneficial, and a significant experience base exists in understanding this environment. Within the period of institutional control, overburden pressure will seal fractures and provide a repository setting that limits radionuclide movement. A salt repository could potentially achieve total containment, with no releases to the environment in undisturbed scenarios for as long as the region is geologically stable. Much of the experience gained from United States repository development, such as seal system design, coupled process simulation, and application of performance assessment methodology, helps define a clear strategy for a heat-generating nuclear waste repository in salt.

Leigh, Christi D. (Sandia National Laboratories, Carlsbad, NM); Hansen, Francis D.

2011-01-01T23:59:59.000Z

162

Development of Next Generation Multiphase Pipe Flow Prediction Tools  

SciTech Connect

The developments of fields in deep waters (5000 ft and more) is a common occurrence. It is inevitable that production systems will operate under multiphase flow conditions (simultaneous flow of gas-oil-and water possibly along with sand, hydrates, and waxes). Multiphase flow prediction tools are essential for every phase of the hydrocarbon recovery from design to operation. The recovery from deep-waters poses special challenges and requires accurate multiphase flow predictive tools for several applications including the design and diagnostics of the production systems, separation of phases in horizontal wells, and multiphase separation (topside, seabed or bottom-hole). It is very crucial to any multiphase separation technique that is employed either at topside, seabed or bottom-hole to know inlet conditions such as the flow rates, flow patterns, and volume fractions of gas, oil and water coming into the separation devices. The overall objective was to develop a unified model for gas-oil-water three-phase flow in wells, flow lines, and pipelines to predict the flow characteristics such as flow patterns, phase distributions, and pressure gradient encountered during petroleum production at different flow conditions (pipe diameter and inclination, fluid properties and flow rates). The project was conducted in two periods. In Period 1 (four years), gas-oil-water flow in pipes were investigated to understand the fundamental physical mechanisms describing the interaction between the gas-oil-water phases under flowing conditions, and a unified model was developed utilizing a novel modeling approach. A gas-oil-water pipe flow database including field and laboratory data was formed in Period 2 (one year). The database was utilized in model performance demonstration. Period 1 primarily consisted of the development of a unified model and software to predict the gas-oil-water flow, and experimental studies of the gas-oil-water project, including flow behavior description and closure relation development for different flow conditions. Modeling studies were performed in two parts, Technology Assessment and Model Development and Enhancement. The results of the Technology assessment study indicated that the performance of the current state of the art two-phase flow models was poor especially for three-phase pipeline flow when compared with the existing data. As part of the model development and enhancement study, a new unified model for gas-oil-water three-phase pipe flow was developed. The new model is based on the dynamics of slug flow, which shares transition boundaries with all the other flow patterns. The equations of slug flow are used not only to calculate the slug characteristics, but also to predict transitions from slug flow to other flow patterns. An experimental program including three-phase gas-oil-water horizontal flow and two-phase horizontal and inclined oil-water flow testing was conducted utilizing a Tulsa University Fluid Flow Projects Three-phase Flow Facility. The experimental results were incorporated into the unified model as they became available, and model results were used to better focus and tailor the experimental study. Finally, during the Period 2, a new three-phase databank has been developed using the data generated during this project and additional data available in the literature. The unified model to predict the gas-oil-water three phase flow characteristics was tested by comparing the prediction results with the data. The results showed good agreements.

Tulsa Fluid Flow

2008-08-31T23:59:59.000Z

163

Dynamic stability experiments in sodium-heated steam generators. [LMFBR  

SciTech Connect

Seventy-two dynamic stability tests were performed in the sodium-heated boiling-water test facility at Argonne National Laboratory. A full-scale LMFBR steam generator tube was employed as the test section operating over the water parameter ranges of 6.9 to 15.9 MPa pressure and 170 to 800 kg/m/sup 2/.s mass flux. The stability thresholds from the test compared well to the predictions of a modified version of a correlation equation recently published by other investigators. Typical experimental data and the modified correlation equation are presented.

France, D.M.; Roy, R.; Carlson, R.D.; Chiang, T.

1984-01-01T23:59:59.000Z

164

Heat Transfer Research 44(1), 130 (2013) ENTROPY GENERATION ANALYSIS  

E-Print Network (OSTI)

Heat Transfer Research 44(1), 1­30 (2013) ENTROPY GENERATION ANALYSIS FOR A PULSATING HEAT­vapor phase 2 Kim, Zhang, & Choi Heat Transfer Research NOMENCLATURE A area, m2 Qin,s,l sensible heat transfer into cp specific heat at constant liquid slug, W pressure, Qout,s,l sensible heat transfer out cv specific

Zhang, Yuwen

165

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

166

Development of Next Generation Multiphase Pipe Flow Prediction Tools  

SciTech Connect

The developments of oil and gas fields in deep waters (5000 ft and more) will become more common in the future. It is inevitable that production systems will operate under multiphase flow conditions (simultaneous flow of gas, oil and water possibly along with sand, hydrates, and waxes). Multiphase flow prediction tools are essential for every phase of hydrocarbon recovery from design to operation. Recovery from deep-waters poses special challenges and requires accurate multiphase flow predictive tools for several applications, including the design and diagnostics of the production systems, separation of phases in horizontal wells, and multiphase separation (topside, seabed or bottom-hole). It is crucial for any multiphase separation technique, either at topside, seabed or bottom-hole, to know inlet conditions such as flow rates, flow patterns, and volume fractions of gas, oil and water coming into the separation devices. Therefore, the development of a new generation of multiphase flow predictive tools is needed. The overall objective of the proposed study is to develop a unified model for gas-oil-water three-phase flow in wells, flow lines, and pipelines to predict flow characteristics such as flow patterns, phase distributions, and pressure gradient encountered during petroleum production at different flow conditions (pipe diameter and inclination, fluid properties and flow rates). In the current multiphase modeling approach, flow pattern and flow behavior (pressure gradient and phase fractions) prediction modeling are separated. Thus, different models based on different physics are employed, causing inaccuracies and discontinuities. Moreover, oil and water are treated as a pseudo single phase, ignoring the distinct characteristics of both oil and water, and often resulting in inaccurate design that leads to operational problems. In this study, a new model is being developed through a theoretical and experimental study employing a revolutionary approach. The basic continuity and momentum equations is established for each phase, and used for both flow pattern and flow behavior predictions. The required closure relationships are being developed, and will be verified with experimental results. Gas-oil-water experimental studies are currently underway for the horizontal pipes. Industry-driven consortia provide a cost-efficient vehicle for developing, transferring, and deploying new technologies into the private sector. The Tulsa University Fluid Flow Projects (TUFFP) is one of the earliest cooperative industry-university research consortia. TUFFP's mission is to conduct basic and applied multiphase flow research addressing the current and future needs of hydrocarbon production and transportation. TUFFP participants and The University of Tulsa are supporting this study through 55% cost sharing.

Cem Sarica; Holden Zhang

2006-05-31T23:59:59.000Z

167

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

168

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

169

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

170

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

171

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

172

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

173

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

174

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.

175

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

176

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

177

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

178

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

179

Numerical Simulations of Dynamos Generated in Spherical Couette Flows  

E-Print Network (OSTI)

at generating a self-sustained magnetic field. No dynamo action occurs for axisymmetric flow while we always, Forest et al., 2002). No self-sustained magnetic fields were observed in the parameter regime where of ferromagnetic impellers, a self-sustained magnetic field has been observed in the Von K¬īarm¬īan Sodium (VKS

Boyer, Edmond

180

Spring 2005 Test #1 1. Steady state heat conduction in a slab with heat generation. (40 points)  

E-Print Network (OSTI)

and goes only in the r direction. The fluid density is , the heat capacity is Cp and the thermal to the surroundings is given by a heat transfer coefficient and Newton's law of cooling q(R) = h (T(R) -T0). a. WriteChEg 356 Spring 2005 Test #1 2/17/05 1. Steady state heat conduction in a slab with heat generation

McCready, Mark J.

Note: This page contains sample records for the topic "generate 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 in a visco-elastic fluid past a stretching sheet with viscous dissipation and internal heat generation  

Science Journals Connector (OSTI)

This paper deals with the study of heat transfer characteristics in the laminar boundary layer flow of a visco-elastic fluid over a linearly stretching continuous surface with ... . The study considers the effect...

P. H. Veena; Subhash Abel; K. RajagopalÖ

2006-05-01T23:59:59.000Z

182

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

183

Generation of mirage effect by heated carbon nanotube thin film  

SciTech Connect

Mirage effect, a common phenomenon in nature, is a naturally occurring optical phenomenon in which lights are bent due to the gradient variation of refraction in the temperature gradient medium. The theoretical analysis of mirage effect generated by heated carbon nanotube thin film is presented both for gas and liquid. Excellent agreement is demonstrated through comparing the theoretical prediction with published experimental results. It is concluded from the theoretical prediction and experimental observation that the mirage effect is more likely to happen in liquid. The phase of deflected optical beam is also discussed and the method for measurement of thermal diffusivity of medium is theoretically verified. Furthermore, a method for measuring the refractive index of gas by detecting optical beam deflection is also presented in this paper.

Tong, L. H. [Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026 (China); USTC-CityU Joint Advanced Research Centre, Suzhou, Jiangsu 215123 (China); Lim, C. W., E-mail: bccwlim@cityu.edu.hk [USTC-CityU Joint Advanced Research Centre, Suzhou, Jiangsu 215123 (China); Department of Civil and Architectural Engineering, City University of Hong Kong, Kowloon, Hong Kong, Peopleís Republic of China and City University of Hong Kong Shenzhen Research Institute, Shenzhen 518057 (China); Li, Y. C. [Department of Modern Mechanics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Chuanzeng; Quoc Bui, Tinh [Department of Civil Engineering, University of Siegen, Paul-Bonatz-Str. 9-11, D-57076 Siegen (Germany)

2014-06-28T23:59:59.000Z

184

A Variable Refrigerant Flow Heat Pump Computer Model in EnergyPlus  

SciTech Connect

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

185

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

186

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.

187

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

Energy.gov (U.S. Department of Energy (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.

188

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.

189

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 andÖ (more)

Jafar, Farial A

2011-01-01T23:59:59.000Z

190

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

191

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

Energy.gov (U.S. Department of Energy (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.

192

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

SciTech Connect

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

193

Development of Design Criteria for Fluid Induced Structural Vibrations in Steam Generators and Heat Exchangers  

SciTech Connect

Flow-induced vibration in heat exchangers has been a major cause of concern in the nuclear industry for several decades. Many incidents of failure of heat exchangers due to apparent flow-induced vibration have been reported through the USNRC incident reporting system. Almost all heat exchangers have to deal with this problem during their operation. The phenomenon has been studied since the 1970s and the database of experimental studies on flow-induced vibration is constantly updated with new findings and improved design criteria for heat exchangers.

Uvan Catton; Vijay K. Dhir; Deepanjan Mitra; Omar Alquaddoomi; Pierangelo Adinolfi

2004-04-06T23:59:59.000Z

194

CHARACTERIZATION OF ELEVATED TEMPERATURE PROPERTIES OF HEAT EXCHANGER AND STEAM GENERATOR ALLOYS  

SciTech Connect

The Next Generation Nuclear Plant project is considering Alloy 800H and Alloy 617 for steam generator and intermediate heat exchangers. It is envisioned that a steam generator would operate with reactor outlet temperatures from 750 to 800 C, while an intermediate heat exchanger for primary to secondary helium would operate up to an outlet temperature of 950 C. Although both alloys are of interest due in part to their technical maturity, a number of specific properties require further characterization for design of nuclear components. Strain rate sensitivity of both alloys has been characterized and is found to be significant above 600 C. Both alloys also exhibit dynamic strain aging, characterized by serrated flow, over a wide range of temperatures and strain rates. High temperature tensile testing of Alloy 617 has been conducted over a range of temperatures. Dynamic strain aging is a concern for these materials since it is observed to result in reduced ductility for many solid solution alloys. Creep, fatigue, and creep-fatigue properties of Alloy 617 have been measured as well, with the goal of determining the influence of the temperature, strain rate and atmosphere on the creep fatigue life of Alloy 617. Elevated temperature properties and implications for codification of the alloys will be described.

J.K. Wright; L.J. Carroll; C.J. Cabet; T. Lillo; J.K. Benz; J.A. Simpson; A. Chapman; R.N. Wright

2012-10-01T23:59:59.000Z

195

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

196

Heat exchanger design for thermoelectric electricity generation from low temperature flue gas streams .  

E-Print Network (OSTI)

??An air-to-oil heat exchanger was modeled and optimized for use in a system utilizing a thermoelectric generator to convert low grade waste heat in flueÖ (more)

Latcham, Jacob G. (Jacob Greco)

2009-01-01T23:59:59.000Z

197

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

198

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 √?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

199

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

200

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

Note: This page contains sample records for the topic "generate 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

Anisotropic flow generated by hard partons in medium  

E-Print Network (OSTI)

Hard partons which are produced copiously in nuclear collisions at the LHC, deposit most of their energy and momentum into the surrounding quark-gluon plasma. We show that this generates streams in the plasma and contributes importantly to flow anisotropies. With the help of event-by-event three-dimensional perfect hydrodynamic simulations we calculate the observable azimuthal anisotropies of hadronic distributions and show that the proposed mechanism is capable of generating non-negligible part of the observed signal. Hence, it must be taken into account in quantitative studies in which one tries to extract the values of viscosities from the comparison of simulated results with measured data.

Tomasik, Boris

2015-01-01T23:59:59.000Z

202

Experimental and thermodynamical analyses of the diesel exhaust vortex generator heat exchanger for optimizing its operating condition  

Science Journals Connector (OSTI)

Abstract In this research, a vortex generator heat exchanger is used to recover exergy from the exhaust of an OM314 diesel engine. Twenty vortex generators with 30į angle of attack are used to increase the heat recovery as well as the low back pressure in the exhaust. The experiments are prepared for five engine loads (0, 20, 40, 60 and 80% of full load), two exhaust gases amount (50†and 100%) and four water mass flow rates (50, 40, 30 and 20†g/s). After a thermodynamical analysis on the obtained data, an optimization study based on Central Composite Design (CCD) is performed due to complex effect of engine loads and water mass flow rates on exergy recovery and irreversibility to reach the best operating condition.

M. Hatami; D.D. Ganji; M. Gorji-Bandpy

2015-01-01T23:59:59.000Z

203

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

204

Nonlinear power flow control applications to conventional generator swing equations subject to variable generation.  

SciTech Connect

In this paper, the swing equations for renewable generators are formulated as a natural Hamiltonian system with externally applied non-conservative forces. A two-step process referred to as Hamiltonian Surface Shaping and Power Flow Control (HSSPFC) is used to analyze and design feedback controllers for the renewable generator system. This formulation extends previous results on the analytical verification of the Potential Energy Boundary Surface (PEBS) method to nonlinear control analysis and design and justifies the decomposition of the system into conservative and non-conservative systems to enable a two-step, serial analysis and design procedure. In particular, this approach extends the work done by developing a formulation which applies to a larger set of Hamiltonian Systems that has Nearly Hamiltonian Systems as a subset. The results of this research include the determination of the required performance of a proposed Flexible AC Transmission System (FACTS)/storage device to enable the maximum power output of a wind turbine while meeting the power system constraints on frequency and phase. The FACTS/storage device is required to operate as both a generator and load (energy storage) on the power system in this design. The Second Law of Thermodynamics is applied to the power flow equations to determine the stability boundaries (limit cycles) of the renewable generator system and enable design of feedback controllers that meet stability requirements while maximizing the power generation and flow to the load. Necessary and sufficient conditions for stability of renewable generators systems are determined based on the concepts of Hamiltonian systems, power flow, exergy (the maximum work that can be extracted from an energy flow) rate, and entropy rate.

Robinett, Rush D., III; Wilson, David Gerald

2010-05-01T23:59:59.000Z

205

Steam Power Stations for Electricity and Heat Generation  

Science Journals Connector (OSTI)

Power plants produce electricity, process heat or district heating, according to their task (Stultz and Kitto 1992). Electric power is the only product of a condensation power plant and the main product of a p...

Dr. Hartmut Spliethoff

2010-01-01T23:59:59.000Z

206

Method of calculation of heat generation rates for DWPF glass. Revision 1  

SciTech Connect

The Waste Acceptance Preliminary Specifications (WAPS) require estimates of the heat generation rate of DWPF waste glasses. Estimates of the heat generation rates of projected glass compositions are to be reported in the Waste Form Qualification Report. Similar estimates for actual production glasses are to be reported in the Production Records. In this report, a method of calculating the heat generation rate from the radionuclide inventory is provided. Application of the method to the DWPF Design-Basis glass indicates that the heat generation rate can be accurately estimated from the Sr-90, Y-90, Cs-137, Ba-137m, and Pu-238 contents alone.

Plodinec, M.J.

1992-03-17T23:59:59.000Z

207

Method of calculation of heat generation rates for DWPF glass. Revision 2  

SciTech Connect

The Waste Acceptance Preliminary Specifications (WAPS) require estimates of the heat generation rate of DWPF waste glasses. Estimates of the heat generation rates of projected glass compositions are to be reported in the Waste Form Qualification Report. Similar estimates for actual production glasses are to be reported in the Production Records. In this report, a method of calculating the heat generation rate from the radionuclide inventory is provided. Application of the method to the DWPF Design-Basis glass indicates that the heat generation rate can be accurately estimated from the Sr-90, Y-90, Cs-137, Ba-137m, and Pu-238 contents alone.

Plodinec, M.J.

1993-02-04T23:59:59.000Z

208

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

209

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

210

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.

211

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

212

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

213

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

214

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

215

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

216

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

217

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

SciTech Connect

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

218

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

219

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

220

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

Note: This page contains sample records for the topic "generate 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

Dependable Hydrogen and Industrial Heat Generation from the Next Generation Nuclear Plant  

SciTech Connect

The Department of Energy is working with industry to develop a next generation, high-temperature gas-cooled nuclear reactor (HTGR) as a part of the effort to supply the US with abundant, clean and secure energy. The Next Generation Nuclear Plant (NGNP) project, led by the Idaho National Laboratory, will demonstrate the ability of the HTGR to generate hydrogen, electricity, and high-quality process heat for a wide range of industrial applications. Substituting HTGR power for traditional fossil fuel resources reduces the cost and supply vulnerability of natural gas and oil, and reduces or eliminates greenhouse gas emissions. As authorized by the Energy Policy Act of 2005, industry leaders are developing designs for the construction of a commercial prototype producing up to 600 MWt of power by 2021. This paper describes a variety of critical applications that are appropriate for the HTGR with an emphasis placed on applications requiring a clean and reliable source of hydrogen. An overview of the NGNP project status and its significant technology development efforts are also presented.

Charles V. Park; Michael W. Patterson; Vincent C. Maio; Piyush Sabharwall

2009-03-01T23:59:59.000Z

222

SOOT GENERATION IN FIRES: AN IMPORTANT PARAMETER FOR ACCURATE CALCULATION OF HEAT RELEASE  

E-Print Network (OSTI)

states that heat of complete combustion per unit mass of oxygen consumed is approximately constant similarly states that heat of complete combustion per unit mass of carbon dioxide generated is approximately constant for most organic liquid, gaseous and solid compounds [1]. The heat of combustion per unit mass

Paris-Sud XI, Université de

223

FARM NET INCOME IMPACT OF SWITCHGRASS PRODUCTION AND CORN STOVER COLLECTION FOR HEAT AND POWER GENERATION  

E-Print Network (OSTI)

FARM NET INCOME IMPACT OF SWITCHGRASS PRODUCTION AND CORN STOVER COLLECTION FOR HEAT AND POWER and Corn Stover Collection for Heat and Power Generation Mitchell A. Myhre Advisor: Associate Professor heat and electric power. To perform this analysis, yield and production potentials were explored

Wisconsin at Madison, University of

224

What Are the Relative Roles of Heating and Cooling in Generating Solar Wind Temperature Anisotropies?  

E-Print Network (OSTI)

a combination of mechanisms of anisotropic heating (e.g., cyclotron-resonant heating and dissipation of kineticWhat Are the Relative Roles of Heating and Cooling in Generating Solar Wind Temperature, anisotropy-driven instabilities such as the cyclotron, mirror, and firehose instabilities limit the allowable

California at Berkeley, University of

225

Novel thermoelectric generator for stationary power waste heat recovery .  

E-Print Network (OSTI)

??Internal combustion engines produce much excess heat that is vented to the atmosphere through the exhaust fluid. Use of solid-state thermoelectric (TE) energy conversion technologyÖ (more)

Engelke, Kylan Wynn.

2010-01-01T23:59:59.000Z

226

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

227

Efficiency and Air Quality Implications of Distributed Generation and Combined Heat  

E-Print Network (OSTI)

Efficiency and Air Quality Implications of Distributed Generation and Combined Heat and Power March 2011 The Issue Distributed generation generates electricity from many small energy sources near where the electricity is used. The use of distributed generation in urban areas, however, can

228

IMPROVING THE EFFICIENCY OF THERMOELECTRIC GENERATORS BY USING SOLAR HEAT CONCENTRATORS  

E-Print Network (OSTI)

IMPROVING THE EFFICIENCY OF THERMOELECTRIC GENERATORS BY USING SOLAR HEAT CONCENTRATORS M. T. de : Thermoelectric generator, Solar heat concentrator, Carnot efficiency I - Introduction The global energy crisis the junctions of two different materials. For a TEG to supply a significant amount of power, several thermo

229

Stirling engines in generating heat and electricity for micro: CHP systems  

Science Journals Connector (OSTI)

In this paper, an analysis of different generating heat and electricity systems with Stirling engine is made from the point of view of benefits and limitations, both operational and economic and environmental. Stirling engine has the ability to work ... Keywords: biomass, fossil fuels, generating heat and electricity system, m-CHP, stirling engine

Dan Scarpete; Krisztina Uzuneanu

2011-03-01T23:59:59.000Z

230

Development of one-dimensional computer code DESOPT for thermal hydraulic design of sodium-heated once through steam generators  

Science Journals Connector (OSTI)

Once-through Steam Generator (SG) is a critical component of Liquid Metal Fast Breeder Reactor (LMFBR) plant. It is a counter current heat exchanger, in which heat is transferred from the hot sodium flowing on the shell side to water/steam in tube side. High pressure subcooled water enters the SG tube from bottom, gets heated up to saturation, goes through nucleate boiling, dry out and post dry out heat transfer, getting converted to saturated steam and finally gets superheated. For this the process design needs to be carried out accurately. A computer code DESOPT has been developed for the process design of straight vertical, serpentine and helical geometries and validated against reported designs in literature. Recently a test facility to test a 5.5 MWt sodium heated steam generator has been commissioned. The predictions of the code have been compared with the measurements and found satisfactory. This paper brings out different heat transfer mechanisms in SG and describes the one-dimensional code, its validation based on literature and in-house tests and presents the results of comparison between predicted and actual operation at different part loads.

G. Vaidyanathan; A.L. Kothandaraman; L.S. Siva Kumar; V. Vinod; I.B. Noushad; K.K. Rajan; P. Kalyanasundaram

2010-01-01T23:59:59.000Z

231

Steam generators two phase flows numerical simulation with liquid and gas momentum equations  

E-Print Network (OSTI)

Steam generators two phase flows numerical simulation with liquid and gas momentum equations M Abstract This work takes place in steam generators flow studies and we consider here steady state three words: Steam Generator, Two-phase Flow, Finite element Email address: Marc.Grandotto@cea.fr (M

Paris-Sud XI, Université de

232

Establishing the Technical Basis for Disposal of Heat-generating Waste in  

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

Establishing the Technical Basis for Disposal of Heat-generating Establishing the Technical Basis for Disposal of Heat-generating Waste in Salt Establishing the Technical Basis for Disposal of Heat-generating Waste in Salt The report summarizes available historic tests and the developed technical basis for disposal of heat-generating waste in salt, and the means by which a safety case for disposal of heat generating waste at a generic salt site can be initiated from the existing technical basis. Though the basis for a salt safety case is strong and has been made by the German repository program, RD&D programs continue in order to help reduce uncertainty, to improve understanding of certain complex processes, to demonstrate operational concepts, to confirm performance expectations, and to improve modeling capabilities utilizing the latest software platforms.

233

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

SciTech Connect

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

234

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

235

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

236

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

237

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

SciTech Connect

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

238

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

239

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

240

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

Note: This page contains sample records for the topic "generate 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.


241

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

242

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

243

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

244

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

245

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

246

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 ďambientĒ temperature. The bound...

Sergio Cuevas; Eduardo Ramos

1991-01-01T23:59:59.000Z

247

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

248

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

249

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...

250

Skutterudite Thermoelectric Generator For Automotive Waste Heat Recovery  

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

Skutterudite TE modules were fabricated and assembled into prototype thermoelectric generators (TEGs), then installed on a standard GM production vehicle and tested for performance

251

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

SciTech Connect

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

252

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

253

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

254

Convection in magnetic fluids with internal heat generation  

SciTech Connect

The effect of a uniform distribution of heat source on the onset of stationary convection in a horizontal Boussinesq magnetic fluid layer bounded by isothermal nonmagnetic boundary is investigated. Solutions are obtained using a higher order Galerkin expansion technique, considering different isothermal boundary combinations (rigid-rigid, rigid-free, and free-free). It is found that the effect of internal magnetic number, due to a heat source, is to make the system more unstable. The results obtained, in the limiting cases, compare well with the existing literature.

Rudraiah, N.; Sekhar, G.N. (Bangalore Univ. (India))

1991-02-01T23:59:59.000Z

255

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 BaeÖ

2002-09-01T23:59:59.000Z

256

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 SassiÖ

2013-01-01T23:59:59.000Z

257

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

SciTech Connect

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

258

Heat transfer and pressure drop for air flow through enhanced passages  

SciTech Connect

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

Obot, N.T.; Esen, E.B.

1992-06-01T23:59:59.000Z

259

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

SciTech Connect

An extensive experimental investigation was carried out to determine the pressure drop and heat transfer characteristics for laminar, transitional and turbulent flow of air through a smooth passage and twenty-three enhanced passages. The internal surfaces of all enhanced passages had spirally shaped geometries; these included fluted, finned/ribbed and indented surfaces. The Reynolds number (Re) was varied between 400 and 50000. The effect of heat transfer (wall cooling or fluid heating) on pressure drop is most significant within the transition region; the recorded pressure drop with heat transfer is much higher than that without heat transfer. The magnitude of this effect depends markedly on the average surface temperature and, to a lesser extent, on the geometric characteristics of the enhanced surfaces. When the pressure drop data are reduced as values of the Fanning friction factor(f), the results are about the same with and without heat transfer for turbulent flow, with moderate differences in the laminar and transition regions.

Obot, N.T.; Esen, E.B.

1992-06-01T23:59:59.000Z

260

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

Note: This page contains sample records for the topic "generate 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

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

262

Heat and mass transfer in a viscoĖelastic 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 viscoĖelastic 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

263

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

264

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

265

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

266

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

267

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

268

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.

269

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

270

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

271

4th Generation District Heating (4GDH): Integrating smart thermal grids into future sustainable energy systems  

Science Journals Connector (OSTI)

Abstract This paper defines the concept of 4th Generation District Heating (4GDH) including the relations to District Cooling and the concepts of smart energy and smart thermal grids. The motive is to identify the future challenges of reaching a future renewable non-fossil heat supply as part of the implementation of overall sustainable energy systems. The basic assumption is that district heating and cooling has an important role to play in future sustainable energy systems Ė including 100 percent renewable energy systems Ė but the present generation of district heating and cooling technologies will have to be developed further into a new generation in order to play such a role. Unlike the first three generations, the development of 4GDH involves meeting the challenge of more energy efficient buildings as well as being an integrated part of the operation of smart energy systems, i.e. integrated smart electricity, gas and thermal grids.

Henrik Lund; Sven Werner; Robin Wiltshire; Svend Svendsen; Jan Eric Thorsen; Frede Hvelplund; Brian Vad Mathiesen

2014-01-01T23:59:59.000Z

272

Testing and Thermodynamic Analysis of Low-Grade Heat Power Generation System Using Organic Rankine Cycle  

Science Journals Connector (OSTI)

Low grade heat power generation system using Organic Rankine Cycle (ORC) was introduced in this work. ... system behaved better in thermodynamic efficiency than stream-Rankine cycle. Numerical thermodynamic model...

Wei Gu; Yiwu Weng; Guangyi Cao

2007-01-01T23:59:59.000Z

273

Improving heat capture for power generation in coal gasification plants  

E-Print Network (OSTI)

Improving the steam cycle design to maximize power generation is demonstrated using pinch analysis targeting techniques. Previous work models the steam pressure level in composite curves based on its saturation temperature ...

Botros, Barbara Brenda

2011-01-01T23:59:59.000Z

274

Table A45. Total Inputs of Energy for Heat, Power, and Electricity Generation  

U.S. Energy Information Administration (EIA) Indexed Site

Total Inputs of Energy for Heat, Power, and Electricity Generation" Total Inputs of Energy for Heat, Power, and Electricity Generation" " by Enclosed Floorspace, Percent Conditioned Floorspace, and Presence of Computer" " Controls for Building Environment, 1991" " (Estimates in Trillion Btu)" ,,"Presence of Computer Controls" ,," for Buildings Environment",,"RSE" "Enclosed Floorspace and"," ","--------------","--------------","Row" "Percent Conditioned Floorspace","Total","Present","Not Present","Factors" " "," " "RSE Column Factors:",0.8,1.3,0.9 "ALL SQUARE FEET CATEGORIES" "Approximate Conditioned Floorspace"

275

Table A31. Total Inputs of Energy for Heat, Power, and Electricity Generation  

U.S. Energy Information Administration (EIA) Indexed Site

Total Inputs of Energy for Heat, Power, and Electricity Generation" Total Inputs of Energy for Heat, Power, and Electricity Generation" " by Value of Shipment Categories, Industry Group, and Selected Industries, 1991" " (Continued)" " (Estimates in Trillion Btu)",,,,"Value of Shipments and Receipts(b)" ,,,," (million dollars)" ,,,"-","-","-","-","-","-","RSE" "SIC"," "," "," "," "," "," "," ",500,"Row" "Code(a)","Industry Groups and Industry","Total","Under 20","20-49","50-99","100-249","250-499","and Over","Factors"

276

Shear flow generation by drift waves revisited P. N. Guzdar and R. G. Kleva  

E-Print Network (OSTI)

Shear flow generation by drift waves revisited P. N. Guzdar and R. G. Kleva Institute for Plasma 2000 The generation of shear flow by drift waves is an important area of investigation. In a recent paper Chen et al., Phys. Plasmas 7, 3129 2000 an elegant formalism was developed for the generation

Rubloff, Gary W.

277

Experimental study on heat transfer to supercritical water flowing through tubes  

SciTech Connect

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

278

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

279

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

SciTech Connect

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 ďnoiseĒ 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

280

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

Note: This page contains sample records for the topic "generate 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

Non-uniform heat generation effect on heat transfer of a non-Newtonian power-law fluid over a non-linearly stretching sheet  

Science Journals Connector (OSTI)

The effects of non-uniform heat generation/absorption and viscous dissipation on heat transfer of a non-Newtonian power-law fluid on a non-linearly stretching surface have ... law index parameter, the Prandtl num...

Mostafa A. A. Mahmoud; Ahmed M. Megahed

2012-06-01T23:59:59.000Z

282

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

283

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

284

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.

285

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

286

Improved solid aerosol generator  

DOE Patents (OSTI)

An improved solid aerosol generator used to produce a gas borne stream of dry, solid particles of predetermined size and concentration. The improved solid aerosol generator nebulizes a feed solution of known concentration with a flow of preheated gas and dries the resultant wet heated aerosol in a grounded, conical heating chamber, achieving high recovery and flow rates. 2 figs.

Prescott, D.S.; Schober, R.K.; Beller, J.

1988-07-19T23:59:59.000Z

287

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

SciTech Connect

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

288

Analysis of the behavior of an experimental absorption heat transformer for water purification for different mass flux rates in the generator  

Science Journals Connector (OSTI)

In the present study, first and second laws of thermodynamics have been used to analyse the performance of an experimental absorption heat transformer for water purification. Irreversibilities, coefficients of performance (COP) and exergy coefficients of performance (ECOP) were determined as function of the mass flow of hot water supplied to the generator and as function of the overall thermal specific energy consumption (OSTEC) parameter defined in this paper. The results showed that the system irreversibilities increase meanwhile the coefficients of performance and the exergy coefficient of performance decrease with an increment of the mass flow of hot water supplied to the generator. Also it was shown that the system performance is better when the production of purified water increases due to the increment of the heat recycled to the generator and evaporator.

Armando Huicochea; Wilfrido Rivera; Hiram MartŪnez; Javier Siqueiros; Erasmo Cadenas

2013-01-01T23:59:59.000Z

289

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

290

Waste heat recovery from the exhaust of a diesel generator using Rankine Cycle  

Science Journals Connector (OSTI)

Abstract Exhaust heat from diesel engines can be an important heat source to provide additional power using a separate Rankine Cycle (RC). In this research, experiments were conducted to measure the available exhaust heat from a 40†kW diesel generator using two Ďoff-the-shelfí heat exchangers. The effectiveness of the heat exchangers using water as the working fluid was found to be 0.44 which seems to be lower than a standard one. This lower performance of the existing heat exchangers indicates the necessity of optimization of the design of the heat exchangers for this particular application. With the available experimental data, computer simulations were carried out to optimize the design of the heat exchangers. Two heat exchangers were used to generate super-heated steam to expand in the turbine using two orientations: series and parallel. The optimized heat exchangers were then used to estimate additional power considering actual turbine isentropic efficiency. The proposed heat exchanger was able to produce 11% additional power using water as the working fluid at a pressure of 15†bar at rated engine load. This additional power resulted into 12% improvement in brake-specific fuel consumption (bsfc). The effects of the working fluid pressure were also investigated to maximize the additional power production. The pressure was limited to 15†bar which was constrained by the exhaust gas temperature. However, higher pressure is possible for higher exhaust gas temperatures from higher capacity engines. This would yield more additional power with further improvements in bsfc. At 40% part load, the additional power developed was 3.4% which resulted in 3.3% reduction in bsfc.

Shekh Nisar Hossain; Saiful Bari

2013-01-01T23:59:59.000Z

291

Relationship between heat transfer intensity and absolute vorticity flux intensity in flat tube bank fin channels with Vortex Generators  

Science Journals Connector (OSTI)

The heat transfer enhancement can be achieved through the secondary flow. It is found that absolute vorticity flux along the main flow can describe the secondary flow intensity and correspond to the heat transfer enhancement averaged in span wise direction. Investigations to verify this phenomenon are reported. The results show that there has a similar distribution for absolute vorticity flux in the main flow direction compared with that for span averaged Nusselt number. The conformance of Nusselt number and absolute vorticity flux shows that absolute vorticity flux can reflect the intensity of heat transfer produced by the secondary flow.

Ke-Wei Song; Liang-Bi Wang

2008-01-01T23:59:59.000Z

292

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

293

System and method for generating current by selective electron heating  

DOE Patents (OSTI)

A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of high-frequency waves into the plasma by means of waveguides. The wave frequency and polarization are chosen such that when the waveguides are tilted in a predetermined fashion, the wave energy is absorbed preferentially by electrons traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas.

Fisch, Nathaniel J. (Princeton, NJ); Boozer, Allen H. (Rocky Hill, NJ)

1984-01-01T23:59:59.000Z

294

Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems  

Science Journals Connector (OSTI)

...simply as resistive heaters. Efficiency is about...office resistance heaters. Usually, traditional heaters draw more electrical...maintenance-free operation dominate other performance...pipelines, polar weather station power generators...

Lon E. Bell

2008-09-12T23:59:59.000Z

295

Cooling, Heating, Generating Power, and Recovering Waste Heat with Thermoelectric Systems  

Science Journals Connector (OSTI)

...the vehicle engine is off. Fuel consumption is reduced...target of 10% fuel reduction...possible in diesel-powered...combustion engines such as those...spectrum of fuels, such as...generation, fuel consumption and CO 2 emissions...

Lon E. Bell

2008-09-12T23:59:59.000Z

296

Time series power flow analysis for distribution connected PV generation.  

SciTech Connect

Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating potential PV impacts.

Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J. [Georgia Institute of Technology, Atlanta, GA; Smith, Jeff [Electric Power Research Institute, Knoxville, TN; Dugan, Roger [Electric Power Research Institute, Knoxville, TN

2013-01-01T23:59:59.000Z

297

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

298

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

299

Effects of lithospheric rigidity on ocean floor bathymetry and heat flow  

SciTech Connect

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

300

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

SciTech Connect

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

Note: This page contains sample records for the topic "generate 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

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

302

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

303

Interpreting Velocities from Heat-Based Flow Sensors by NumericalSimulation  

SciTech Connect

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

304

The preliminary design of thermoelectric generation system using the fluid heat sources  

SciTech Connect

This paper describes the preliminary design of a thermoelectric generation system using the fluid heat sources available as the waste heat of the phosphoric acid fuel cells. The thermoelectric generator consists of many thermoelectric generation units. For estimating the output performance of the thermoelectric generator, an equilibrium thermal circuit was derived from an analytic model of a thermoelectric generation unit. Based on the equivalent thermal circuit, the output performance at thermal equilibrium was calculated by iteration. In this paper, the output performance was estimated considering the cold side pumping power. The calculation was done by assuming a heat source temperature of about 450K on the hot side, about 310 K on the cold side, and 2,000kWth as heat exchange capacity. The electric power of the generator with a size of 1.5 x 1.5 x 1.4 (h) m{sup 3} was found to be about 70 kW and its power density, about 1.5 kW/m{sup 2} excepting the pumping power on the cold water side.

Hori, Y.; Ito, T. [Central Research Inst. of Electric Power Industry, Yokosuka, Kanagawa (Japan)

1995-12-31T23:59:59.000Z

305

Simplified Heat Generation Model for Lithium ion battery used in Electric Vehicle  

Science Journals Connector (OSTI)

It is known that temperature variations inside a battery may greatly affect its performance, life, and reliability. In an effort to gain a better understanding of the heat generation in Lithium ion batteries, a simple heat generation models were constructed in order to predict the thermal behaviour of a battery pack. The Lithium ion battery presents in this paper is Lithium Iron Phosphate (LiFePO4). The results show that the model can be viewed as an acceptable approximation for the variation of the battery pack temperature at a continuous discharge current from data provided by the manufacturer and literature.

Nur Hazima Faezaa Ismail; Siti Fauziah Toha; Nor Aziah Mohd Azubir; Nizam Hanis Md Ishak; Mohd Khair Hassan; Babul Salam Ksm Ibrahim

2013-01-01T23:59:59.000Z

306

Table A15. Total Inputs of Energy for Heat, Power, and Electricity Generation  

U.S. Energy Information Administration (EIA) Indexed Site

Total Inputs of Energy for Heat, Power, and Electricity Generation" Total Inputs of Energy for Heat, Power, and Electricity Generation" " by Value of Shipment Categories, Industry Group, and Selected Industries, 1994" " (Estimates in Trillion Btu)" ,,,," Value of Shipments and Receipts(b)" ,,,," "," (million dollars)" ,,,,,,,,,"RSE" "SIC"," "," "," "," "," "," "," ",500,"Row" "Code(a)","Industry Group and Industry","Total","Under 20","20-49","50-99","100-249","250-499","and Over","Factors" ,"RSE Column Factors:",0.6,1.3,1,1,0.9,1.2,1.2

307

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 0.003Ė0.015†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

308

Generation of magnetoacoustic zonal flows by Alfven waves in a rotating plasma  

SciTech Connect

Analytical theory of nonlinear generation of magnetoacoustic zonal flows in a rotating plasma is developed. As the primary modes causing such a generation, a totality of the Alfven waves are considered, along with the kinetic, inertial, and rotational. It is shown that in all these cases of the Alfven waves the generation is possible if the double plasma rotation frequency exceeds the zonal flow frequency.

Mikhailovskii, A. B.; Lominadze, J. G.; Churikov, A. P.; Erokhin, N. N.; Tsypin, V. S.; Smolyakov, A. I.; Galvao, R. M. O. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, 1, Kurchatov Square, Moscow 123182 (Russian Federation); Kharadze Abastumani National Astrophysical Observatory, 2a, Kazbegi Avenue, Tbilisi 0160 (Georgia); Syzran Branch of Samara Technical University, 45, Sovetskaya Str., Syzran, Samara Region 446001 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Square, 1, Moscow 123182 (Russian Federation); Brazilian Center for Physics Research, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil); University of Saskatchewan, 116 Science Place, Saskatoon S7N 5E2 (Canada); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Square, 1, Moscow 123182 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil); Brazilian Center for Physics Research, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil)

2007-08-15T23:59:59.000Z

309

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

SciTech Connect

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

310

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.

311

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

312

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

313

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

314

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

315

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 velocity‚??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

316

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

SciTech Connect

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

317

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

318

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

319

Evaluation of performance of combined heat and power systems with dual power generation units (D-CHP).  

E-Print Network (OSTI)

?? In this research, a new combined heat and power (CHP) system configuration has been proposed that uses two power generation units (PGU) operating simultaneouslyÖ (more)

Knizley, Alta Alyce

2013-01-01T23:59:59.000Z

320

Enhanced Geothermal in Nevada: Extracting Heat From the Earth to Generate  

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

Enhanced Geothermal in Nevada: Extracting Heat From the Earth to Enhanced Geothermal in Nevada: Extracting Heat From the Earth to Generate Sustainable Power Enhanced Geothermal in Nevada: Extracting Heat From the Earth to Generate Sustainable Power April 12, 2013 - 11:17am Addthis Learn the basics of enhanced geothermal systems technology. I Infographic by Sarah Gerrity. Learn the basics of enhanced geothermal systems technology. I Infographic by Sarah Gerrity. Erin R. Pierce Erin R. Pierce Digital Communications Specialist, Office of Public Affairs What does this project do? Desert Peak 2 is the nation's first commercial enhanced geothermal system to supply electricity to the grid. Based in Churchill County, Nevada, the project has increased power

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321

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

SciTech Connect

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

322

Zonal flows generated by small-scale drift-Alfven modes  

SciTech Connect

The generation of zonal flows by small-scale drift-Alfven (SSDA) modes is investigated. It is shown that these zonal flows can be generated by a monochromatic wave packet of SSDA modes propagating in the ion diamagnetic drift direction. The corresponding zonal-flow instability resembles a hydrodynamic one. Its growth rate depends on the spectrum purity of the wave packet; it decreases for relatively weak spectrum broadening and the instability turns into a resonant one, and eventually is suppressed, as the broadening increases. A general conclusion of this work is that the SSDA modes are less effective for driving zonal flows than standard drift modes.

Mikhailovskii, A.B.; Smolyakov, A.I.; Kovalishen, E.A.; Shirokov, M.S.; Tsypin, V.S.; Botov, P.V.; Galvao, R.M.O. [Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation); University of Saskatchewan, 116 Science place, Saskatoon S7 N 5E2 (Canada) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation); Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow 123182 (Russian Federation) and Moscow Engineering Physics Institute, Kashirskoe Shosse 31, Moscow 115409 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil); Nonlinear Physics Laboratory, Moscow Institute of Physics and Technology, Institutskii per. 9, Dolgoprudnyi 141700, Moscow Region (Russian Federation) and Institute of Nuclear Fusion, Russian Research Centre Kurchatov Institute, Kurchatov Sq., 1, Moscow, 123182 (Russian Federation); Physics Institute, University of Sao Paulo, Cidade Universitaria, 05508-900, Sao Paulo (Brazil) and Brazilian Center for Research in Physics, Rua Xavier Sigaud, 150, 22290-180, Rio de Janeiro (Brazil)

2006-04-15T23:59:59.000Z

323

GREENHOUSE GAS REDUCTION POTENTIAL WITH COMBINED HEAT AND POWER WITH DISTRIBUTED GENERATION PRIME MOVERS - ASME 2012  

SciTech Connect

Pending or recently enacted greenhouse gas regulations and mandates are leading to the need for current and feasible GHG reduction solutions including combined heat and power (CHP). Distributed generation using advanced reciprocating engines, gas turbines, microturbines and fuel cells has been shown to reduce greenhouse gases (GHG) compared to the U.S. electrical generation mix due to the use of natural gas and high electrical generation efficiencies of these prime movers. Many of these prime movers are also well suited for use in CHP systems which recover heat generated during combustion or energy conversion. CHP increases the total efficiency of the prime mover by recovering waste heat for generating electricity, replacing process steam, hot water for buildings or even cooling via absorption chilling. The increased efficiency of CHP systems further reduces GHG emissions compared to systems which do not recover waste thermal energy. Current GHG mandates within the U.S Federal sector and looming GHG legislation for states puts an emphasis on understanding the GHG reduction potential of such systems. This study compares the GHG savings from various state-of-the- art prime movers. GHG reductions from commercially available prime movers in the 1-5 MW class including, various industrial fuel cells, large and small gas turbines, micro turbines and reciprocating gas engines with and without CHP are compared to centralized electricity generation including the U.S. mix and the best available technology with natural gas combined cycle power plants. The findings show significant GHG saving potential with the use of CHP. Also provided is an exploration of the accounting methodology for GHG reductions with CHP and the sensitivity of such analyses to electrical generation efficiency, emissions factors and most importantly recoverable heat and thermal recovery efficiency from the CHP system.

Curran, Scott [ORNL; Theiss, Timothy J [ORNL; Bunce, Michael [ORNL

2012-01-01T23:59:59.000Z

324

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

325

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 (¬Ķg, 1g, 2g). To fully understand the high heat transfer potential

326

A turbulence model for buoyant flows based on vorticity generation.  

SciTech Connect

A turbulence model for buoyant flows has been developed in the context of a k-{var_epsilon} turbulence modeling approach. A production term is added to the turbulent kinetic energy equation based on dimensional reasoning using an appropriate time scale for buoyancy-induced turbulence taken from the vorticity conservation equation. The resulting turbulence model is calibrated against far field helium-air spread rate data, and validated with near source, strongly buoyant helium plume data sets. This model is more numerically stable and gives better predictions over a much broader range of mesh densities than the standard k-{var_epsilon} model for these strongly buoyant flows.

Domino, Stefan Paul; Nicolette, Vernon F.; O'Hern, Timothy John; Tieszen, Sheldon R.; Black, Amalia Rebecca

2005-10-01T23:59:59.000Z

327

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

SciTech Connect

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

328

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

SciTech Connect

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

329

Parametric design study of ``mini-generator`` with 6-watt heat source  

SciTech Connect

The Fairchild study showed that generator designs based on a single 1-watt RHU had very poor thermal efficiencies. At their optimum operating point, more than half of the generated heat was lost through the thermal insulation. This resulted in system efficiency of only 2.2%, compared to 7.2% for current Radioisotope Thermoelectric Generators (RTGs). Moreover, there were serious doubts about the fabricability of the required multicouples, particularly of the series/parallel connections between the large number (900) of thermoelectric legs of very small cross-section (0.21 mm square). All in all, the preceding paper showed that neither JPL`s Power Stick design nor the Fairchild-generated derivatives based on the 1-watt heat source looked promising. The present paper describes a similar parametric study of a mini-generator based on a 6-watt heat source, and compares its performance and fabricability to that of the optimum Power Stick derivative and of the current RTG design for the same mission. {copyright} 1995 {ital American} {ital Institute} {ital of} {ital Physics}

Schock, A.; Or, C.T. [Orbital Sciences Corporation, 20301 Century Blvd., Germantown, Maryland 20874 (United States)

1995-01-20T23:59:59.000Z

330

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

331

STOCHASTIC FLOW SEQUENCE GENERATION AND ASPINALL UNIT OPERATIONS  

E-Print Network (OSTI)

of the University of Colorado in partial fulfillment of the requirement for the degree of Master of Science by Professor Balaji Rajagopalan The Aspinall Unit is comprised of three reservoirs that lie on the western for the Colorado River Basin, paleo reconstructed flows dating back to the 1500's suggest that such events

332

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

SciTech Connect

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

333

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

334

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

SciTech Connect

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

335

Tidal flow over threedimensional topography generates outofforcingplane harmonics  

E-Print Network (OSTI)

the barotropic tide [Munk and Wunsch, 1998; Egbert and Ray, 2000]. The transfer of this barotropic energy from energy conversion from the barotropic to the baroclinic tide. The generation of internal waves by tidal circulation is maintained by roughly 2 TW of mixing energy, about half of which is extracted from

Texas at Austin. University of

336

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

SciTech Connect

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

337

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 ¬Ľ 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

338

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

339

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

SciTech Connect

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

340

Power Generation Using District Heat: Energy Efficient Retrofitted Plus-energy School Rostock  

Science Journals Connector (OSTI)

Abstract The Mathias-Thesen-School in Rostock/Germany is one of few schools which has been retrofitted as an Energy Plus building as part of the energy-efficient school research project ďEnEff:SchuleĒ sponsored by the German Ministry of Economics and Technology. The original building complex (build 1960, useful area 2200sqm) is being converted into a compact building by extending the main building with two new buildings connected by light-flooded buffer spaces. Both the existing building and the new buildings will be highly insulated. The low remaining heating demand will be covered using an innovative concept, made reasonable by the low primary energy factor of the district heat in Rostock: A small-scale Organic Rankine Cycle system generates electricity using high-temperature district heat. The excess heat of the generator is then used to heat the building via low-temperature distribution systems. In combination with two small-scale onsite wind turbines and building integrated photovoltaics a positive primary energy balance is achieved. For this balance, the development of the primary energy factors (PEF) of the German electricity mix is crucial: With rising generation from renewable energies the PEF of electricity in Germany is going to descent, leading to higher primary energy factors of cogeneration systems. In the Mathias-Thesen-School in Rostock a detailed monitoring system was installed, which has been checked and reworked for proper functioning. First measures to optimize the HVAC system and user comfort have been taken. The second construction phase will take place in 2014, after which the performance of the ORC system and the Energy Balance will be analyzed in detail.

Simon Winiger; Sebastian Herkel; Gesa Haroske

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "generate 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

Original article: An automatic unstructured grid generation method for viscous flow simulations  

Science Journals Connector (OSTI)

High aspect-ratio grids are required for accurate solution of boundary layer and wake flow. An approach for the efficient generation of isotropic and stretched viscous unstructured grids is introduced in this paper. The proposed grid generation algorithm ... Keywords: Stretched cells, Unstructured grid, Viscous layers

Seyed Saied Bahrainian; Zahra Mehrdoost

2012-09-01T23:59:59.000Z

342

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

SciTech Connect

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

343

Evaluation Metrics for Intermediate Heat Exchangers for Next Generation Nuclear Reactors  

SciTech Connect

The Department of Energy (DOE) is working with industry to develop a next generation, high-temperature gas-cooled reactor (HTGR) as a part of the effort to supply the United States with abundant, clean, and secure energy as initiated by the Energy Policy Act of 2005 (EPAct; Public Law 109-58,2005). The NGNP Project, led by the Idaho National Laboratory (INL), will demonstrate the ability of the HTGR to generate hydrogen, electricity, and/or high-quality process heat for a wide range of industrial applications.

Piyush Sabharwall; Eung Soo Kim; Nolan Anderson

2011-06-01T23:59:59.000Z

344

Investigation of the effect of electron cyclotron heating on runaway generation in the KSTAR tokamak  

Science Journals Connector (OSTI)

Wave enhanced runaway generation is expected to play an important role in the conversion of plasma current into runaway current during major disruptions. The fast electrons created by electron cyclotron heating (ECH) were used to study this issue in KSTAR. It is found that the fast electrons driven by ECH can enhance runaway production in the flat top phase with high loop voltage. The runaway current in disruptions was not enhanced by the ECH produced fast electron population due to the strong magnetic fluctuations which inhibited the generation of runaway electrons. It is found that a complete loss of existing \\{REs\\} during thermal quench has occurred in KSTAR limiter configuration discharges.

Z.Y. Chen; W.C. Kim; A.C. England; S.W. Yoon; K.D. Lee; Y.S. Lee; J.W. Yoo; Y.W. Yu; Y.K. Oh; J.G. Kwak; M. Kwon

2011-01-01T23:59:59.000Z

345

Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures  

SciTech Connect

There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.

Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau

2014-06-01T23:59:59.000Z

346

Electromagnetic Induction Heat Generation of Nano?ferrofluid and Other Stimulants for Heavy Oil Recovery  

Science Journals Connector (OSTI)

Nano?ferrofluid and graphite?fluid are proposed to be used as stimulants for heavy oil recovery processes using electromagnetic induction. The heat generation in the stimulants will be used for reducing the viscosity of heavy oil. The temperature increase of the stimulants are observed with the presence of electromagnetic induction. These increments are better compared to those of the varying concentration of salt water (brine) usually exist in the oil reservoir.

A. A. Pramana; D. Abdassah; S. Rachmat; A. Mikrajuddin

2010-01-01T23:59:59.000Z

347

Thermoelectric energy converter for generation of electricity from low-grade heat  

DOE Patents (OSTI)

A thermoelectric energy conversion device which includes a plurality of thermoelectric elements is described. A hot liquid is supplied to one side of each element and a cold liquid is supplied to the other side of each element. The thermoelectric generator may be utilized to produce power from low-grade heat sources such as ocean thermal gradients, solar ponds, and low-grade geothermal resources. (WHK)

Jayadev, T.S.; Benson, D.K.

1980-05-27T23:59:59.000Z

348

Assessment of district heating and cooling supply from Goudey Generating Station  

SciTech Connect

This paper addresses the feasibility analysis of retrofitting the New York State Electric and Gas (NYSEG) Goudey Generating Station for district heating and cooling supply to the SUNY-Binghamton Campus. The project involved detailed analysis of the power plant retrofit, dispatch analysis of the retrofitted Goudey Station in the New York Power Pool, environmental and permitting assessment, retrofit analysis of the SUNY campus to low temperature hot water and economic analysis.

McIntire, M.E.; Hall, D.; Beal, D.J. [New York State Electric & Gas Corporation, Binghamton, NY (United States)] [and others

1995-06-01T23:59:59.000Z

349

Experimental study of vortex generators effects on low Reynolds number airfoils in turbulent flow  

Science Journals Connector (OSTI)

In the present work, we study the aerodynamic effects of triangular vortex generators, as passive flow control devices, placed on the upper surface of an airfoil submitted to a low Reynolds number turbulent flow. In the experiments, different configurations of those devices have been studied. An Eppler 387 airfoil was used. The tests were performed in a turbulent boundary layer wind tunnel using a two component aerodynamic balance and flow visualisation systems. Turbulent flow characterisation was made by means of hot wire anemometry. Calculations of local turbulent intensity as well as temporal and spatial turbulent scales were made. Vortex generators were located at 10% and 20% of the airfoil chord from the leading edge, modifying its angle of incidence refereed to the free stream. The results show changes in the aerodynamic section coefficients, C1, Cd and C1, for the different vortex generator configurations. Neither hysteresis effects, nor leading edge bubbles were found in the experiments.

Juan Sebasti√°n Delnero; Julio Mara√Īon Di Leo; Mauricio Ezequiel Camocardi; Mariano A. Martinez; Jorge L. Colman Lerner

2012-01-01T23:59:59.000Z

350

Investigation And Evaluation Of The Systemwide Economic Benefits Of Combined Heat And Power Generation In The New York State Energy Market.  

E-Print Network (OSTI)

??Combined Heat and Power (CHP) is the production of electricity and the simultaneous utilization of the heat produced by the generator prime mover. The energyÖ (more)

Baquero, Ricardo

2008-01-01T23:59:59.000Z

351

Simulation of hydration/dehydration of CaO/Ca(OH){sub 2} chemical heat pump reactor for cold/hot heat generation  

SciTech Connect

A chemical heat pump (CHP) utilizes reversible reactions involving significant endothermic and exothermic heats of reaction in order to develop a heat pump effect by storing and releasing energy while transforming it from chemical to thermal energy and vice versa. In this paper, the authors present a mathematical model and its numerical solution for the heat and mass transport phenomena occurring in the reactant particle bed of the CHP for heat storage and cold/hot heat generation based on the CaO/Ca(OH){sub 2} reversible hydration/dehydration reaction. Transient conservation equations of mass and energy transport including chemical kinetics are solved numerically subject to appropriate boundary and initial conditions to examine the influence of the mass transfer resistance on the overall performance of this CHP configuration. These results are presented and discussed with the aim of enhancing the CHP performance in the next generation reactor designs. The CHP can store thermal energy in industrial waste heat, solar heat, terrestrial heat, etc. in the form of chemical energy, and release it at various temperature levels during the heat-demand period.

Ogura, Hironao; Shimojyo, Rui; Kage, Hiroyuki; Matsuno, Yoshizo; Mujumdar, A.S.

1999-09-01T23:59:59.000Z

352

Theoretical and experimental estimation of limiting input heat flux for thermoelectric power generators with passive cooling  

Science Journals Connector (OSTI)

Abstract This paper focuses on theoretical and experimental analysis used to establish the limiting heat flux for passively cooled thermoelectric generators (TEG). 2 commercially available TEGís further referred as type A and type B with different allowable hot side temperatures (150†įC and 250†įC respectively) were investigated in this research. The thermal resistance of TEG was experimentally verified against the manufacturerís specifications and used for theoretical analysis in this paper. A theoretical model is presented to determine the maximum theoretical heat flux capacity of both the TEGís. The conventional methods are used for cooling of TEGís and actual limiting heat flux is experimentally established for various cold end cooling configurations namely bare plate, finned block and heat pipe with finned condenser. Experiments were performed on an indoor setup and outdoor setup to validate the results from the theoretical model. The outdoor test setup consist of a fresnel lens solar concentrator with manual two axis solar tracking system for varying the heat flux, whereas the indoor setup uses electric heating elements to vary the heat flux and a low speed wind tunnel blows the ambient air past the device to simulate the outdoor breezes. It was observed that bare plate cooling can achieve a maximum heat flux of 18,125†W/m2 for type A and 31,195†W/m2 for type B at ambient wind speed of 5†m/s while maintaining respective allowable temperature over the hot side of TEGís. Fin geometry was optimised for the finned block cooling by using the fin length and fin gap optimisation model presented in this paper. It was observed that an optimum finned block cooling arrangement can reach a maximum heat flux of 26,067†W/m2 for type A and 52,251†W/m2 for type B TEG at ambient wind speed of 5†m/s of ambient wind speed. The heat pipe with finned condenser used for cooling can reach 40,375†W/m2 for type A TEG and 76,781†W/m2 for type B TEG.

Ashwin Date; Abhijit Date; Chris Dixon; Randeep Singh; Aliakbar Akbarzadeh

2015-01-01T23:59:59.000Z

353

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

SciTech Connect

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

354

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

355

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

Energy.gov (U.S. Department of Energy (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.

356

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

357

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

SciTech Connect

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

358

High Temperature Fuel Cell Tri-Generation of Power, Heat & H2 from Biogas  

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

National Fuel Cell Research Center, 2012 1/22 National Fuel Cell Research Center, 2012 1/22 High Temperature Fuel Cell Tri-Generation of Power, Heat & H 2 from Biogas Jack Brouwer, Ph.D. June 19, 2012 DOE/ NREL Biogas Workshop - Golden, CO © National Fuel Cell Research Center, 2012 2/22 Outline * Introduction and Background * Tri-Generation/Poly-Generation Analyses * OCSD Project Introduction © National Fuel Cell Research Center, 2012 3/22 Introduction and Background * Hydrogen fuel cell vehicle performance is outstanding * Energy density of H 2 is much greater than batteries * Rapid fueling, long range ZEV * H 2 must be produced * energy intensive, may have emissions, fossil fuels, economies of scale * Low volumetric energy density of H 2 compared to current infrastructure fuels (@ STP)

359

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

360

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

Note: This page contains sample records for the topic "generate 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

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

362

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 gasĖliquid 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

363

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.

364

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

SciTech Connect

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

365

Shear flow generation from the interaction of neoclassical and drift wave transport processes  

SciTech Connect

Self-consistent shear flow generation from the interaction of neoclassical and drift wave turbulence effects is investigated. The neoclassical poloidal flow damping is shown to compete with the flow generation driven by the divergence of the Reynolds stress. When there is no external driving force except for the free energy released from toroidal shear flow, the turbulent fluctuations occur as a transient pulse which takes the system along an equilibrium path to a relaxed state. External torques, such as parallel neutral beam injection, are needed to maintain significant fluctuation levels. For a system driven by a fixed ion temperature gradient, although linearly the poloidal shear flow generated substantially reduces the growth rate, the simulation results show that a sequence of nonlinear pulses occurs that eventually build the fluctuations up to a level that is not significantly affected by the poloidal flow. In this new, highly nonlinear state the transport is intermittent occurring through a sequence of pulses of duration 100 L{sub n}/c{sub s} for typical parameters.

Su, X.N.; Yushmanov, P.N.; Dong, J.Q.; Horton, W.

1993-10-01T23:59:59.000Z

366

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

367

Electric Power Generation Using Low Bandgap TPV Cells in a Gas?fired Heating Furnace  

Science Journals Connector (OSTI)

Low bandgap TPV cells are preferred for electric power generation in TPV cogeneration systems. Recently significant progress has been made in fabrication of low bandgap semiconductor TPV devices such as InGaAsSb and InGaAs cells. However it appears that only limited data are available in the literature with respect to the performance of these TPV cells in combustion?driven TPV systems. In the research presented in this paper power generation using recently?developed InGaAsSb TPV cells has been investigated in a gas?fired space heating appliance. The combustion performance of the gas burner associated with a broadband radiator was evaluated experimentally. The radiant power density and radiant efficiency of the gas?heated radiator were determined at different degrees of exhaust heat recuperation. Heat recuperation is shown to have a certain effect on the combustion operation and radiant power output. The electric output characteristics of the InGaAsSb TPV devices were investigated under various combustion conditions. It was found that the cell short circuit density was greater than 1 A/cm2 at a radiator temperature of 930įC when an optical filter was used. An electric power density of 0.54 W/cm2 was produced at a radiator temperature of 1190įC. Furthermore modeling calculations were carried out to reveal the influence of TPV cell bandgap and radiator temperature on power output and conversion efficiency. Finally the design aspects of combustion?driven TPV systems were analyzed showing that development of a special combustion device with high conversion level of fuel chemical energy to useful radiant energy is required to improve further the system efficiency.

K. Qiu; A. C. S. Hayden

2003-01-01T23:59:59.000Z

368

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

SciTech Connect

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

369

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

SciTech Connect

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

370

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

SciTech Connect

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

371

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

372

EIS-0302: Transfer of the Heat Source/Radioisotope Thermoelectric Generator Assembly and Test Operations From the Mound Site  

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

This EIS analyzes DOE's proposed transfer of the Heat Source/Radioisotope Thermoelectric Generator (HS/RTG) operations at the Mound Site near Miamisburg, Ohio, to an alternative DOE site.

373

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

SciTech Connect

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

374

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

SciTech Connect

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

375

The Impact of RELAP5 Pipe Break Flow Rates Associated With Reverse Flow Limiter Removal for Steam Generator Replacement  

SciTech Connect

Pipe break flow rates are calculated for a main feedwater line break (FWLB) in the main steam valve vault (MSVV) for a PWR Steam Generator Replacement (SGR). A reverse flow limiter is installed in the original steam generator (OSG) feedwater nozzle to limit the blowdown flowrate in the event of a postulated FWLB. This feature is not incorporated in the replacement steam generator (RSG) design. The change in RSG nozzle design in conjunction with new operating conditions results in increased FWLB mass and energy releases which can impact environmental temperatures and pressures and flooding levels. In the United States, benchmarking for safety related analyses is necessary in consideration of 10CFR50.59 requirements. RELAP5/MOD3 is used to model the pipe break flowrates for a FWLB at different break locations. The benchmark FWLB blowdown releases are larger than the OSG design basis blowdown releases due to differences in RELAP5/MOD3 versions which are found to have different algorithms for subcooled choked flow. The SGR FWLB blowdown release rates are determined to have minimal impact on the compartment temperature and pressure response. However, the flooding levels and associated equipment qualification are potentially impacted. Modeling techniques used to minimize the impact of the SGR blowdown releases on MSVV flooding levels include modeling flashing effects, more realistic RSG temperature distribution, inventory depletion and Auxiliary Feedwater (AFW) flow initiation time, and considering loss of offsite power scenarios. A detailed flooding hazard evaluation is needed, which considers the actual main feedwater isolation times to ensure that environmentally qualified safety related components, required to mitigate the effects of a FWLB inside the MSVV, can perform their safety function prior to being submerged. (authors)

Dong Zheng; Jarvis, Julie M.; Vieira, Allen T. [Bechtel Power Corporation, Frederick, Maryland (United States)

2006-07-01T23:59:59.000Z

376

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

377

Optimal Trajectory Generation in Ocean Flows Tamer Inanc, Shawn C. Shadden and Jerrold E. Marsden  

E-Print Network (OSTI)

currents to help propel the gliders around the ocean for sustainable missions. The idea of exploitingOptimal Trajectory Generation in Ocean Flows Tamer Inanc, Shawn C. Shadden and Jerrold E. Marsden near optimal trajectories for autonomous underwater gliders in a dynamic ocean environment. This opens

Marsden, Jerrold

378

The case for endurance testing of sodium-heated steam generators  

SciTech Connect

It is generally believed that a nuclear power comeback before the end of the century will be through the vehicle of the light water reactor (LWR). The newer designs, with their important technical and economic advances, should attract wide interest and result in commercial success for the manufacturers and their utility customers. To develop the liquid-metal fast breeder reactor (LMFBR), approximately $30 billion has been spent worldwide, a third of which has been spent in the US. As a result of this considerable investment, most of the technical obstacles to deployment of the LMFBR have been removed with a few exceptions, one of which is the long-term performance of sodium-heated steam generators. Of the difficulties that have beset the current vintage of nuclear power plants, the performance of steam generators in pressurized water reactors (PWRs) was the most egregious. There was very little development testing and no model testing of PWR steam generators. Development occurred in the plants themselves resulting in many outages and more than $5 billion in lost revenue and replacement power costs. As a result, the electric utility industry is certain to exercise caution regarding acquisition of the LMFBR and will demand strong objective evidence of steam generator reliability. Only long-term endurance testing of prototypic models under prototypic conditions will satisfy this demand.

Onesto, A.T.; Zweig, H.R.; Gibbs, D.C. (Energy Technology Engineering Center, Canoga Park, CA (United States))

1992-01-01T23:59:59.000Z

379

Development of thermoelectric power generation system utilizing heat of combustible solid waste  

SciTech Connect

The paper presents the development of thermoelectric power generation system utilizing heat of municipal solid waste. The systematic classification and design guideline are proposed in consideration of the characteristics of solid waste processing system. The conceptual design of thermoelectric power generation system is carried out for a typical middle scale incinerator system (200 ton/day) by the local model. Totally the recovered electricity is 926.5 kWe by 445 units (569,600 couples). In order to achieve detailed design, one dimensional steady state model taking account of temperature dependency of the heat transfer performance and thermoelectric properties is developed. Moreover, small scale on-site experiment on 60 W class module installed in the real incinerator is carried out to extract various levels of technological problems. In parallel with the system development, high temperature thermoelectric elements such as Mn-Si and so on are developed aiming the optimization of ternary compound and high performance due to controlled fine-grain boundary effect. The manganese silicide made by shrinking-rate controlled sintering method performs 5 ({mu}W/cm K{cflx 2}) in power factor at 800 K. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Kajikawa, T.; Ito, M.; Katsube, I. [Shonan Institute of Technology, Fujisawa, Kanagawa, 251 (Japan); Shibuya, E. [NKK Corporation, Yokohama, Kanagawa, 230 (Japan)

1994-08-10T23:59:59.000Z

380

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

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381

Air bottoming cycle: Use of gas turbine waste heat for power generation  

SciTech Connect

This paper presents a thermodynamic analysis of the Air Bottoming Cycle (ABC) as well as the results of a feasibility study for using the Air Bottoming Cycle for gas turbine waste heat recovery/power generation on oil/gas platforms in the North Sea. The basis for the feasibility study was to utilize the exhaust gas heat from an LM2500PE gas turbine. Installation of the ABC on both a new and an existing platform have been considered. A design reference case is presented, and the recommended ABC is a two-shaft engine with two compressor intercoolers. The compression pressure ratio was found optimal at 8:1. The combined gas turbine and ABC shaft efficiency wa/s calculated to 46.6 percent. The LM2500PE gas turbine contributes with 36.1 percent while the ABC adds 10.5 percent points to the gas turbine efficiency. The ABC shaft power output is 6.6 MW when utilizing the waste heat of an LM2500PE gas turbine. A preliminary thermal and hydraulic design of the ABC main components (compressor, turbine, intercoolers, and recuperator) was carried out. The recuperator is the largest and heaviest component (45 tons). A weight and cost breakdown of the ABC is presented. The total weight of the ABC package was calculated to 154 metric tons, and the ABC package cost to 9.4 million US$. An economical examination for three different cases was carried out. The results show that the ABC alternative (LM2500PE + ABC) is economical, with a rather good margin, compared to the other alternatives. The conclusion is that the Air Bottoming Cycle is an economical alternative for power generation on both new platforms and on existing platforms with demand for more power.

Bolland, O.; Foerde, M. [Norwegian Univ. of Science and Technology, Trondheim (Norway). Div. of Thermal Energy and Hydropower; Haande, B. [Oil Engineering Consultants, Sandvika (Norway)

1996-04-01T23:59:59.000Z

382

On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers, Volumes 1, 2.  

SciTech Connect

The overall purpose of this Nuclear Engineering Education Research (NEER) project was to integrate new, innovative, and existing technologies to develop a fault diagnostics and characterization system for nuclear plant steam generators (SG) and heat exchangers (HX). Issues related to system level degradation of SG and HX tubing, including tube fouling, performance under reduced heat transfer area, and the damage caused by stress corrosion cracking, are the important factors that influence overall plant operation, maintenance, and economic viability of nuclear power systems. The research at The University of Tennessee focused on the development of techniques for monitoring process and structural integrity of steam generators and heat exchangers. The objectives of the project were accomplished by the completion of the following tasks. All the objectives were accomplished during the project period. This report summarizes the research and development activities, results, and accomplishments during June 2001 √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬? September 2004. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development and testing of a high-fidelity nodal model of a U-tube steam generator (UTSG) to simulate the effects of fouling and to generate a database representing normal and degraded process conditions. Application of the group method of data handling (GMDH) method for process variable prediction. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development of a laboratory test module to simulate particulate fouling of HX tubes and its effect on overall thermal resistance. Application of the GMDH technique to predict HX fluid temperatures, and to compare with the calculated thermal resistance. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development of a hybrid modeling technique for process diagnosis and its evaluation using laboratory heat exchanger test data. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development and testing of a sensor suite using piezo-electric devices for monitoring structural integrity of both flat plates (beams) and tubing. Experiments were performed in air, and in water with and without bubbly flow. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development of advanced signal processing methods using wavelet transforms and image processing techniques for isolating flaw types. √?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬?√?¬∑ Development and implementation of a new nonlinear and non-stationary signal processing method, called the Hilbert-Huang transform (HHT), for flaw detection and location. This is a more robust and adaptive approach compared to the wavelet transform

Upadhyaya, Belle R.; Hines, J. Wesley; Lu, Baofu; Huang, Xuedong; Penha, Rosani, L.; Perillo, Sergio, R.; Zhao, Ke

2005-06-03T23:59:59.000Z

383

On-Line Monitoring and Diagnostics of the Integrity of Nuclear Plant Steam Generators and Heat Exchangers.  

SciTech Connect

The overall purpose of this Nuclear Engineering Education Research (NEER) project was to integrate new, innovative, and existing technologies to develop a fault diagnostics and characterization system for nuclear plant steam generators (SG) and heat exchangers (HX). Issues related to system level degradation of SG and HX tubing, including tube fouling, performance under reduced heat transfer area, and the damage caused by stress corrosion cracking, are the important factors that influence overall plant operation, maintenance, and economic viability of nuclear power systems. The research at The University of Tennessee focused on the development of techniques for monitoring process and structural integrity of steam generators and heat exchangers. The objectives of the project were accomplished by the completion of the following tasks. All the objectives were accomplished during the project period. This report summarizes the research and development activities, results, and accomplishments during June 2001-September 2004. (1) Development and testing of a high-fidelity nodal model of a U-tube steam generator (UTSG) to simulate the effects of fouling and to generate a database representing normal and degraded process conditions. Application of the group method of data handling (GMDH) method for process variable prediction. (2) Development of a laboratory test module to simulate particulate fouling of HX tubes and its effect on overall thermal resistance. Application of the GMDH technique to predict HX fluid temperatures, and to compare with the calculated thermal resistance. (3) Development of a hybrid modeling technique for process diagnosis and its evaluation using laboratory heat exchanger test data. (4) Development and testing of a sensor suite using piezo-electric devices for monitoring structural integrity of both flat plates (beams) and tubing. Experiments were performed in air, and in water with and without bubbly flow. (5) Development of advanced signal processing methods using wavelet transforms and image processing techniques for isolating flaw types. (6) Development and implementation of a new nonlinear and non-stationary signal processing method, called the Hilbert-Huang transform (HHT), for flaw detection and location. This is a more robust and adaptive approach compared to the wavelet transform. (7) Implementation of a moving-window technique in the time domain for detecting and quantifying flaw types in tubular structures. A window zooming technique was also developed for flaw location in tubes. (8) Theoretical study of elastic wave propagation (longitudinal and shear waves) in metallic flat plates and tubing with and without flaws. (9) Simulation of the Lamb wave propagation using the finite-element code ABAQUS. This enabled the verification of the experimental results. The research tasks included both analytical research and experimental studies. The experimental results helped to enhance the robustness of fault monitoring methods and to provide a systematic verification of the analytical results. The results of this research were disseminated in scientific meetings. A journal manuscript was submitted for publication. The new findings of this research have potential applications in aerospace and civil structures. The report contains a complete bibliography that was developed during the course of the project.

Belle R. Upadhyaya; J. Wesley Hines

2004-09-27T23:59:59.000Z

384

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

385

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

386

Entropy Generation In The Viscous Layer Of A Turbulent Channel Flow  

SciTech Connect

The local (pointwise) entropy generation rate per unit volume S''' is a key to improving many energy processes and applications. Entropy generation due to friction occurs from viscous dissipation of mean-flow kinetic energy (called "direct dissipation") and dissipation of turbulent kinetic energy into thermal energy ("indirect" or turbulent dissipation). The objective of the present study is to compare two approaches for the prediction of S''' for the viscous layer in near asymptotic (high Reynolds number) turbulent flows. By employing available direct numerical simulations (DNS) it was found that about two-thirds of the entropy generation occurs in this layer. A popular approximate approach does not agree with the result from the more exact evaluation of S''' but its integral falls within about four per cent at the edge of the viscous layer.

D. M. McEligot; E. J. Walsh; E. Laurien; James R. Wolf

2006-09-01T23:59:59.000Z

387

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 shearĖpressure-driven flow in the developing and fully developed regions. The mixed shearĖpressure-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 shearĖpressure-driven flow.

J. Ghazanfarian and A. Abbassi

2010-08-13T23:59:59.000Z

388

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

SciTech Connect

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

389

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

SciTech Connect

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

390

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

391

Heat Transfer -2 A heat generating ( ) flat plate fuel element of thickness 2L is covered with flat plate steel cladding of  

E-Print Network (OSTI)

with flat plate steel cladding of thickness b. The heat generated is removed by a fluid at T, which adjoins on both sides On the sketch show regions where dT/dx is zero, constant and increasing. T , h x LL bb SteelSteel

Virginia Tech

392

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)

393

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

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

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

394

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

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

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

395

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

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

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

396

Certification testing of the Los Alamos National Laboratory Heat Source/Radioisotopic Thermoelectric Generator shipping container  

SciTech Connect

The Heat Source/Radioisotopic Thermoelectric Generator shipping counter is a Type B packaging currently under development by Los Alamos National Laboratory. Type B packaging for transporting radioactive material is required to maintain containment and shielding after being exposed to normal and hypothetical accident environments defined in Title 10 of the Code of Federal Regulations Part 71. A combination of testing and analysis is used to verify the adequacy of this packaging design. This report documents the testing portion of the design verification. Six tests were conducted on a prototype package: a water spray test, a 4-foot normal conditions drop test, a 30-foot drop test, a 40-inch puncture test, a 30-minute thermal test, and an 8-hour immersion test.

Bronowski, D.R.; Madsen, M.M.

1991-09-01T23:59:59.000Z

397

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

398

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

SciTech Connect

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

399

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

400

Waste Classification based on Waste Form Heat Generation in Advanced Nuclear Fuel Cycles Using the Fuel-Cycle Integration and Tradeoffs (FIT) Model - 13413  

SciTech Connect

This study explores the impact of wastes generated from potential future fuel cycles and the issues presented by classifying these under current classification criteria, and discusses the possibility of a comprehensive and consistent characteristics-based classification framework based on new waste streams created from advanced fuel cycles. A static mass flow model, Fuel-Cycle Integration and Tradeoffs (FIT), was used to calculate the composition of waste streams resulting from different nuclear fuel cycle choices. This analysis focuses on the impact of waste form heat load on waste classification practices, although classifying by metrics of radiotoxicity, mass, and volume is also possible. The value of separation of heat-generating fission products and actinides in different fuel cycles is discussed. It was shown that the benefits of reducing the short-term fission-product heat load of waste destined for geologic disposal are neglected under the current source-based radioactive waste classification system, and that it is useful to classify waste streams based on how favorable the impact of interim storage is in increasing repository capacity. (authors)

Djokic, Denia [Department of Nuclear Engineering, University of California - Berkeley, 4149 Etcheverry Hall, Berkeley, CA 94720-1730 (United States)] [Department of Nuclear Engineering, University of California - Berkeley, 4149 Etcheverry Hall, Berkeley, CA 94720-1730 (United States); Piet, Steven J.; Pincock, Layne F.; Soelberg, Nick R. [Idaho National Laboratory - INL, 2525 North Fremont Avenue, Idaho Falls, ID 83415 (United States)] [Idaho National Laboratory - INL, 2525 North Fremont Avenue, Idaho Falls, ID 83415 (United States)

2013-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "generate 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.


401

Anisotropic transverse flow introduction in Monte Carlo generators for heavy ion collisions  

Science Journals Connector (OSTI)

Anisotropic transverse flow patterns that are observed in relativistic heavy ion collisions can be added to the available microscopic Monte Carlo event generators as a final state modification to the azimuthal angles of the particles, which are generated isotropically. The method proposed for this purpose by A. M. Poskanzer and S. A. Voloshin [Phys. Rev. C 58, 1671 (1998)] is valid only for small values of the Fourier coefficients vn and therefore it is not suitable for simulations with large values of anisotropy such as the ones predicted for Pb-Pb collisions at the LHC. We present here a possible solution to treat the cases of large anisotropies.

M. Masera; G. Ortona; M. G. Poghosyan; F. Prino

2009-06-26T23:59:59.000Z

402

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

403

Proposal for the Award of a Contract for the Supply and Installation of a gas Turbine for Combined Generation of Electricity and Heat in the Heating Plant on the Meyrin Site  

E-Print Network (OSTI)

Proposal for the Award of a Contract for the Supply and Installation of a gas Turbine for Combined Generation of Electricity and Heat in the Heating Plant on the Meyrin Site

1994-01-01T23:59:59.000Z

404

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

405

ESS 2012 Peer Review - New Generation Aqueous Base Redox Flow Battery Component Development - Wei Wang, PNNL  

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

Generation Aqueous Base Redox Flow Generation Aqueous Base Redox Flow Battery Component Development Wei Wang, Qingtao Luo, Xiaoliang Wei, Bin Li, Zimin Nie, Baowei Chen, Yuyan Shao, Vijayakumar Murugesan, Amy Chen, Gordon, Xia, Liyu Li, Gary Z. Yang, Vincent Sprenkle Pacific Northwest National Laboratory 902 Battelle Boulevard P. O. Box 999 Richland, WA 99352, USA DOE Stationary Energy Storage Program Review, Washington, DC Sept. 26-28, 2012 Dr. Imre Gyuk 1 2 Review of previous work 2.5M, ~30Wh/L, -5~50 o C Mixed-acid VRB Double Energy Density Extend temperature window Charge Discharge Charge Discharge Charge Discharge Catholyte: VO 2+ + Cl - + H 2 O - e VO 2 Cl + 2H + őĶ co =1.0 V Anolyte: V 3+ + e V 2+ őĶ ao =-0.25 Overall: VO 2+ + Cl

406

Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector  

DOE Patents (OSTI)

An optical heat generation and detection system generates a first non-destructive pulsed beam of electromagnetic radiation that is directed upon a sample containing at least one interface between similar or dissimilar materials. The first pulsed beam of electromagnetic radiation, a pump beam (21a), produces a non-uniform temperature change within the sample. A second non-destructive pulsed beam of electromagnetic radiation, a probe beam (21b), is also directed upon the sample. Physical and chemical properties of the materials, and of the interface, are measured by observing changes in a transient optical response of the sample to the probe beam, as revealed by a time dependence of changes in, by example, beam intensity, direction, or state of polarization. The system has increased sensitivity to interfacial properties including defects, contaminants, chemical reactions and delaminations, as compared to conventional non-destructive, non-contact techniques. One feature of this invention is a determination of a Kapitza resistance at the interface, and the correlation of the determined Kapitza resistance with a characteristic of the interface, such as roughness, delamination, the presence of contaminants, etc.

Maris, Humphrey J (Barrington, RI); Stoner, Robert J (Duxbury, MA)

1998-01-01T23:59:59.000Z

407

Apparatus and method for characterizing thin film and interfaces using an optical heat generator and detector  

DOE Patents (OSTI)

An optical heat generation and detection system generates a first non-destructive pulsed beam of electromagnetic radiation that is directed upon a sample containing at least one interface between similar or dissimilar materials. The first pulsed beam of electromagnetic radiation, a pump beam, produces a non-uniform temperature change within the sample. A second non-destructive pulsed beam of electromagnetic radiation, a probe beam, is also directed upon the sample. Physical and chemical properties of the materials, and of the interface, are measured by observing changes in a transient optical response of the sample to the probe beam, as revealed by a time dependence of changes in, by example, beam intensity, direction, or state of polarization. The system has increased sensitivity to interfacial properties including defects, contaminants, chemical reactions and delaminations, as compared to conventional non-destructive, non-contact techniques. One feature of this invention is a determination of a Kapitza resistance at the interface, and the correlation of the determined Kapitza resistance with a characteristic of the interface, such as roughness, delamination, the presence of contaminants, etc. 31 figs.

Maris, H.J.; Stoner, R.J.

1998-05-05T23:59:59.000Z

408

On the Heating of the Solar Corona and the Acceleration of the Low-Speed Solar Wind by Acoustic Waves Generated in Corona  

E-Print Network (OSTI)

We investigate possibilities of solar coronal heating by acoustic waves generated not at the photosphere but in the corona, aiming at heating in the mid- to low-latitude corona where the low-speed wind is expected to come from. Acoustic waves of period tau ~ 100s are triggered by chromospheric reconnection, one model of small scale magnetic reconnection events recently proposed by Sturrock. These waves having a finite amplitude eventually form shocks to shape sawtooth waves (N-waves), and directly heat the surrounding corona by dissipation of their wave energy. Outward propagation of the N-waves is treated based on the weak shock theory, so that the heating rate can be evaluated consistently with physical properties of the background coronal plasma without setting a dissipation length in an ad hoc manner. We construct coronal structures from the upper chromosphere to the outside of 1AU for various inputs of the acoustic waves having a range of energy flux of F_{w,0} = (1-20) times 10^5 erg cm^{-2} s^{-1} and a period of tau = 60-300s. The heating by the N-wave dissipation effectively works in the inner corona and we find that the waves of F_{w,0} >= 2 times 10^5 erg cm^{-2} s^{-1} and tau >= 60s could maintain peak coronal temperature, T_{max} > 10^6 K. The model could also reproduce the density profile observed in the streamer region. However, due to its short dissipation length, the location of T_{max} is closer to the surface than the observation, and the resultant flow velocity of the solar wind is lower than the observed profile of the low-speed wind. The cooperations with other heating and acceleration sources with the larger dissipation length are inevitable to reproduce the real solar corona.

Takeru Ken Suzuki

2002-06-14T23:59:59.000Z

409

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

SciTech Connect

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

410

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

411

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

412

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, ZŁrich, Switzerland,Performance of ground source heat pump system in a near-zero

Hong, Tainzhen

2010-01-01T23:59:59.000Z

413

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

SciTech Connect

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

414

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

415

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 becauseÖ (more)

Xing, Keqiang

2007-01-01T23:59:59.000Z

416

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

417

Minimum entropy generation due to heat transfer and fluid friction in a parabolic trough receiver with non-uniform heat flux at different rim angles and concentration ratios  

Science Journals Connector (OSTI)

Abstract In this paper, Monte Carlo ray-tracing and computational fluid dynamics are used to numerically investigate the minimum entropy generation due to heat transfer and fluid friction in a parabolic trough receiver. The analysis was carried out for rim angles in the range 40įĖ120į, concentration ratios in the range 57Ė143, Reynolds numbers in the range 1.02†◊†104Ė1.36†◊†106 and fluid temperatures in the range 350Ė650†K. Results show existence of an optimal Reynolds number at any given combination of fluid temperature, concentration ratio and rim angle for which the total entropy generation is a minimum. The total entropy generation was found to increase as the rim angle reduced, concentration ratio increased and fluid temperature reduced. The high entropy generation rates at low rim angles are mainly due to high peak temperatures in the absorber tube at these low rim angles.

Aggrey Mwesigye; Tunde Bello-Ochende; Josua P. Meyer

2014-01-01T23:59:59.000Z

418

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

SciTech Connect

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourierís 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 Fourierís 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

419

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

SciTech Connect

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

420

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

SciTech Connect

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

Note: This page contains sample records for the topic "generate 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

Municipal District Heating and Cooling Co-generation System Feasibility Research  

E-Print Network (OSTI)

In summer absorption refrigerating machines provide cold water using excess heat from municipal thermoelectric power plant through district heating pipelines, which reduces peak electric load from electricity networks in summer. The paper simulates...

Zhang, W.; Guan, W.; Pan, Y.; Ding, G.; Song, X.; Zhang, Y.; Li, Y.; Wei, H.; He, Y.

2006-01-01T23:59:59.000Z

422

Influences of peripherally-cut twisted tape insert on heat transfer and thermal performance characteristics in laminar and turbulent tube flows  

SciTech Connect

Effects of peripherally-cut twisted tape insert on heat transfer, friction loss and thermal performance factor characteristics in a round tube were investigated. Nine different peripherally-cut twisted tapes with constant twist ratio (y/W = 3.0) and different three tape depth ratios (DR = d/W = 0.11, 0.22 and 0.33), each with three different tape width ratios (WR = w/W = 0.11, 0.22 and 0.33) were tested. Besides, one typical twisted tape was also tested for comparison. The measurement of heat transfer rate was conducted under uniform heat flux condition while that of friction factor was performed under isothermal condition. Tests were performed with Reynolds number in a range from 1000 to 20,000, using water as a working fluid. The experimental results revealed that both heat transfer rate and friction factor in the tube equipped with the peripherally-cut twisted tapes were significantly higher than those in the tube fitted with the typical twisted tape and plain tube, especially in the laminar flow regime. The higher turbulence intensity of fluid in the vicinity of the tube wall generated by the peripherally-cut twisted tape compared to that induced by the typical twisted tape is referred as the main reason for achieved results. The obtained results also demonstrated that as the depth ratio increased and width ratio decreased, the heat transfer enhancement increased. Over the range investigated, the peripherally-cut twisted tape enhanced heat transfer rates in term of Nusselt numbers up to 2.6 times (turbulent regime) and 12.8 times (laminar regime) of that in the plain tube. These corresponded to the maximum performance factors of 1.29 (turbulent regime) and 4.88 (laminar regime). (author)

Eiamsa-ard, Smith [Department of Mechanical Engineering, Faculty of Engineering, Mahanakorn University of Technology, Bangkok 10530 (Thailand); Seemawute, Panida [Department of Civil Engineering, Faculty of Engineering, Mahanakorn University of Technology, Bangkok 10530 (Thailand); Wongcharee, Khwanchit [Department of Chemical Engineering, Faculty of Engineering, Mahanakorn University of Technology, Bangkok 10530 (Thailand)

2010-09-15T23:59:59.000Z

423

Thermoelectric generators incorporating phase-change materials for waste heat recovery from engine exhaust  

DOE Patents (OSTI)

Thermoelectric devices, intended for placement in the exhaust of a hydrocarbon fuelled combustion device and particularly suited for use in the exhaust gas stream of an internal combustion engine propelling a vehicle, are described. Exhaust gas passing through the device is in thermal communication with one side of a thermoelectric module while the other side of the thermoelectric module is in thermal communication with a lower temperature environment. The heat extracted from the exhaust gasses is converted to electrical energy by the thermoelectric module. The performance of the generator is enhanced by thermally coupling the hot and cold junctions of the thermoelectric modules to phase-change materials which transform at a temperature compatible with the preferred operating temperatures of the thermoelectric modules. In a second embodiment, a plurality of thermoelectric modules, each with a preferred operating temperature and each with a uniquely-matched phase-change material may be used to compensate for the progressive lowering of the exhaust gas temperature as it traverses the length of the exhaust pipe.

Meisner, Gregory P; Yang, Jihui

2014-02-11T23:59:59.000Z

424

A shielded storage and processing facility for radioisotope thermoelectric generator heat source production  

SciTech Connect

A shielded storage rack has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the U.S. Department of Energy's (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE's Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which processes and stores assembled GPHS modules, prior to their installation into RTGs. The shield rack design is simple and effective, with the result that background radiation levels within Hanford's MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford's calculations assume five times the GPHS inventory of that assumed for Mound.

Sherrell, D.L. (Westinghouse Hanford Company, P.O. Box 1970, Mail Stop N1-42, Richland, Washington 99352 (United States))

1993-01-15T23:59:59.000Z

425

A shielded storage and processing facility for radioisotope thermoelectric generator heat source production  

SciTech Connect

This report discusses a shielded storage rack which has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the US Department of Energy's (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE's Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which process and stores assembled GPHS modules, prior to their installation into RTGS. The shield rack design is simple and effective, with the result that background radiation levels within Hanford's MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford's calculations assume five times the GPHS inventory of that assumed for Mound.

Sherrell, D.L.

1992-06-01T23:59:59.000Z

426

A shielded storage and processing facility for radioisotope thermoelectric generator heat source production  

SciTech Connect

This report discusses a shielded storage rack which has been installed as part of the Radioisotope Power Systems Facility (RPSF) at the US Department of Energy`s (DOE) Hanford Site in Washington State. The RPSF is designed to replace an existing facility at DOE`s Mound Site near Dayton, Ohio, where General Purpose Heat Source (GPHS) modules are currently assembled and installed into Radioisotope Thermoelectric Generators (RTG). The overall design goal of the RPSF is to increase annual production throughput, while at the same time reducing annual radiation exposure to personnel. The shield rack design successfully achieved this goal for the Module Reduction and Monitoring Facility (MRMF), which process and stores assembled GPHS modules, prior to their installation into RTGS. The shield rack design is simple and effective, with the result that background radiation levels within Hanford`s MRMF room are calculated at just over three percent of those typically experienced during operation of the existing MRMF at Mound, despite the fact that Hanford`s calculations assume five times the GPHS inventory of that assumed for Mound.

Sherrell, D.L.

1992-06-01T23:59:59.000Z

427

Application of bio-oils from lignocellulosic biomass to transportation, heat and power generationóA review  

Science Journals Connector (OSTI)

Abstract This review will be concentrated on the application of bio-oil produced from the cellulosic biomass among the various liquid biofuels to transport fuels, heat and power generation as substitute. Main application of bio-oil and biocrude from two main thermochemical processes, i.e., pyrolysis and liquefaction include boiler for heat and electricity production, diesel engine or gas turbine for power generation, and diesel engine for transportation fuel. Fast pyrolysis is the most popular process for converting cellulosic biomass to high yield of bio-oil with relatively low cost. For the application of bio-oils to transportation, heat and power generation, physical upgrading methods such as emulsions (bio-oil/diesel or bio-oil/biodiesel ) and blends of bio-oil/oxygenated fuel (ethanol, diglyme) were mainly used and tested. The studies on the spray characteristics of emulsions and blends in diesel engine condition are not available in the literature. In most studies on the combustion and emission characteristics of emulsions and blends, CO emission was increased in most fuels and engines tested and HC was increased or comparable to diesel operation. However, \\{NOx\\} and soot emissions were decreased in most case of experiments. In the pressure-swirl nozzle for gas turbine application, preheating and blending techniques were employed to reduce the SMD of spray. In case of blend for the application of heat and power generation, E20 blend was mainly selected in most studies. Most studies related to bio-oil combustion in burners, diesel engines and gas turbines demonstrated the higher HC, CO and soot emissions than the original design fuel. Although the properties of bio-oil/methanol blend were widely investigated, there are no studies available about the application of bio-oil/methanol blend to transportation, heat and power generation in the literature. In addition, more research is required for the combustion of upgraded bio-oils for transportation application.

Soo-Young No

2014-01-01T23:59:59.000Z

428

Heat pump system  

DOE Patents (OSTI)

An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

Swenson, Paul F. (Shaker Heights, OH); Moore, Paul B. (Fedhaven, FL)

1983-01-01T23:59:59.000Z

429

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

SciTech Connect

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

430

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

SciTech Connect

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

431

Comparison of analytical models for zonal flow generation in ion-temperature-gradient mode turbulence  

SciTech Connect

During the past years the understanding of the multi scale interaction problems have increased significantly. However, at present there exists a flora of different analytical models for investigating multi scale interactions and hardly any specific comparisons have been performed among these models. In this work two different models for the generation of zonal flows from ion-temperature-gradient (ITG) background turbulence are discussed and compared. The methods used are the coherent mode coupling model and the wave kinetic equation model (WKE). It is shown that the two models give qualitatively the same results even though the assumption on the spectral difference is used in the (WKE) approach.

Anderson, J.; Miki, K.; Uzawa, K.; Li, J.; Kishimoto, Y. [Dept. Fundamental Energy Science, School of Energy Science, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 (Japan)

2006-11-30T23:59:59.000Z

432

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

SciTech Connect

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

433

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

434

Investigating and establishing limiting heat flux for passively cooled and solar concentrated thermoelectric power generation system.  

E-Print Network (OSTI)

??Thermoelectric generators (TEG) working on the principle of Seebeck effect have gathered the attention during this period as a potential device that can generate electricityÖ (more)

Date, A

2014-01-01T23:59:59.000Z

435

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

SciTech Connect

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

436

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

437

Cylinder wall waste heat recovery from liquid-cooled internal combustion engines utilizing thermoelectric generators.  

E-Print Network (OSTI)

?? This report is a dissertation proposal that focuses on the energy balance within an internal combustion engine with a unique coolant-based waste heat recoveryÖ (more)

Armstead, John Randall

2012-01-01T23:59:59.000Z

438

Calculation of the heats of combustion of aromatic hydrocarbons contained in power-generating fuel  

Science Journals Connector (OSTI)

The additive method of group contributions is used for the calculation of the heats of combustion of aromatic hydrocarbons of different structures.

E. V. Sagadeev; V. V. Sagadeev

2006-07-01T23:59:59.000Z

439

Calculation of the Heats of Combustion of Saturated Hydrocarbons Contained in Power-Generating Fuels  

Science Journals Connector (OSTI)

An empirical method is suggested for the calculation of the heats of combustion of saturated hydrocarbons by the additive scheme proceeding from their...

E. V. Sagadeev; V. V. Sagadeev

2002-07-01T23:59:59.000Z

440

Advanced Thermoelectric Materials and Generator Technology for Automotive Waste Heat at GM  

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

Overview of design, fabrication, integration, and test of working prototype TEG for engine waste heat recovery on Suburban test vehicle, and continuing investigation of skutterudite materials systems

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

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.

442

Turbidity current flow over an obstacle and phases of sediment wave generation  

E-Print Network (OSTI)

We study the flow of particle-laden turbidity currents down a slope and over an obstacle. A high-resolution 2D computer simulation model is used, based on the Navier-Stokes equations. It includes poly-disperse particle grain sizes in the current and substrate. Particular attention is paid to the erosion and deposition of the substrate particles, including application of an active layer model. Multiple flows are modeled from a lock release that can show the development of sediment waves (SW). These are stream-wise waves that are triggered by the increasing slope on the downstream side of the obstacle. The initial obstacle is completely erased by the resuspension after a few flows leading to self consistent and self generated SW that are weakly dependant on the initial obstacle. The growth of these waves is directly related to the turbidity current being self sustaining, that is, the net erosion is more than the net deposition. Four system parameters are found to influence the SW growth: (1) slope, (2) current ...

Strauss, Moshe

2011-01-01T23:59:59.000Z

443

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

444

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 80Ė90% 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. Diťguez; F.J. Echave; O. Sanz; M. Montes; L.M. GandŪa

2014-01-01T23:59:59.000Z

445

PUBLISHED ONLINE: 20 JUNE 2010 | DOI: 10.1038/NPHYS1686 Propulsion generated by diffusion-driven flow  

E-Print Network (OSTI)

LETTERS PUBLISHED ONLINE: 20 JUNE 2010 | DOI: 10.1038/NPHYS1686 Propulsion generated by diffusion plates4 . Here we show that buoyancy-driven flows can also generate propulsion. Specifically, we find for transport processes in regions of varying fluid density, such as marine snow aggregation at ocean

Loss, Daniel

446

Effects of the ship motion on gasĖsolid 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 gasĖsolid 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 gasĖsolid 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

447

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

SciTech Connect

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

448

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

SciTech Connect

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

449

General-purpose heat source: Research and development program. Radioisotope thermoelectric generator impact tests: RTG-1 and RTG-2  

SciTech Connect

The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. The first two RTG Impact Tests were designed to provide information on the response of a fully loaded RTG to end-on impact against a concrete target. The results of these tests indicated that at impact velocities up to 57 m/s the converter shell and internal components protect the GPHS capsules from excessive deformation. At higher velocities, some of the internal components of the RTG interact with the GPHS capsules to cause excessive localized deformation and failure.

Reimus, M.A.H.; Hinckley, J.E.; George, T.G.

1996-07-01T23:59:59.000Z

450

General-purpose heat source: Research and development program, radioisotope thermoelectric generator/thin fragment impact test  

SciTech Connect

The general-purpose heat source provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements in a radioisotope thermoelectric generator (RTG). Because the potential for a launch abort or return from orbit exists for any space mission, the heat source response to credible accident scenarios is being evaluated. This test was designed to provide information on the response of a loaded RTG to impact by a fragment similar to the type of fragment produced by breakup of the spacecraft propulsion module system. The results of this test indicated that impact by a thin aluminum fragment traveling at 306 m/s may result in significant damage to the converter housing, failure of one fueled clad, and release of a small quantity of fuel.

Reimus, M.A.H.; Hinckley, J.E.

1996-11-01T23:59:59.000Z

451

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 kĖ? (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

452

Generation of high charge state metal ion beams by electron cyclotron resonance heating of vacuum arc plasma in cusp trap  

SciTech Connect

A method for generating high charge state heavy metal ion beams based on high power microwave heating of vacuum arc plasma confined in a magnetic trap under electron cyclotron resonance conditions has been developed. A feature of the work described here is the use of a cusp magnetic field with inherent ''minimum-B'' structure as the confinement geometry, as opposed to a simple mirror device as we have reported on previously. The cusp configuration has been successfully used for microwave heating of gas discharge plasma and extraction from the plasma of highly charged, high current, gaseous ion beams. Now we use the trap for heavy metal ion beam generation. Two different approaches were used for injecting the vacuum arc metal plasma into the trap - axial injection from a miniature arc source located on-axis near the microwave window, and radial injection from sources mounted radially at the midplane of the trap. Here, we describe preliminary results of heating vacuum arc plasma in a cusp magnetic trap by pulsed (400 {mu}s) high power (up to 100 kW) microwave radiation at 37.5 GHz for the generation of highly charged heavy metal ion beams.

Nikolaev, A. G.; Savkin, K. P.; Oks, E. M.; Vizir, A. V.; Yushkov, G. Yu. [High Current Electronics Institute, Siberian Division of Russian Academy Science, Tomsk 634055 (Russian Federation); Vodopyanov, A. V.; Izotov, I. V.; Mansfeld, D. A. [Institute of Applied Physics, Russian Academy of Science, Nizhniy Novgorod 603950 (Russian Federation)

2012-02-15T23:59:59.000Z

453

Status of Segmented Element Thermoelectric Generator for Vehicle Waste Heat Recovery  

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

Discusses progress of thermoelectric generator development at BSST and assessment of potential to enter commercial operation in vehicles

454

A New Generation of Hsp90 Inhibitors: Addressing Isoform Selectivity and Heat Shock Induction  

E-Print Network (OSTI)

The 90 kDa heat shock proteins (Hsp90) are molecular chaperones that are upregulated in response to cellular stress and are responsible for the conformational maturation, activation and/or stability of more than 200 client proteins. Many...

Duerfeldt, Adam Scott

2011-12-31T23:59:59.000Z

455

Project Profile: Baseload CSP Generation Integrated with Sulfur-Based Thermochemical Heat Storage  

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

General Atomics, under the Baseload CSP FOA, is demonstrating the engineering feasibility of using a sulfur-based thermochemical cycle to store heat from a CSP plant and support baseload power...

456

Heating of Coronal Holes and Generation of the Solar Wind by Ion-Cyclotron Resonance  

Science Journals Connector (OSTI)

We discuss a new model to describe the heating of the magnetically open solar corona and ... acceleration of the fast solar wind by the cyclotron resonant interaction of coronal ions with ion-cyclotron waves. Thi...

Philip A. Isenberg

2001-01-01T23:59:59.000Z

457

Thermoelectric generator  

SciTech Connect

A thermoelectric generator unit is described comprising: a hot side heat exchanger including a plate having extruded retention posts projecting from one surface of the plate, and fins adapted for contact with a heating source. The fins are positioned between two of the retention posts. Retention rods are inserted between the retention posts and the base of the fins to retain the fin in thermal contact with the plate surface upon insertion of the retention rod between the engaging surface of the post and the corresponding fin. Thermoelectric semi-conductor modules are in thermal contact with the opposite side of the hot side heat exchanger plate from the contact with the fins. The modules are arranged in a grid pattern so that heat flow is directed into each of the modules from the hot side heat exchanger. The modules are connected electrically so as to combine their electrical output; and a cold side heat exchanger is in thermal contact with the modules acting as a heat sink on the opposite side of the module from the hot side heat exchanger plate so as to produce a thermal gradient across the modules.

Shakun, W.; Bearden, J.H.; Henderson, D.R.

1988-03-29T23:59:59.000Z

458

Temperature and thermal stress distributions for the HFIR permanent reflector generated by nuclear heating  

SciTech Connect

The beryllium permanent reflector of the High Flux Isotope Reactor has the main functions for slowing down and reflecting the neutrons and housing the experimental facilities. The reflector is heated as a result of the nuclear reaction. Heat is removed mainly by the cooling water passing through the densely distributed coolant holes along the vertical or axial direction of the reflector. The reflector neutronic distribution and its heating rate are calculated by J.C. Gehin of the Oak Ridge National Laboratory by applying the Monte Carlo Code MCNP. The heat transfer boundary conditions along several reflector interfaces are estimated to remove additional heat from the reflector. The present paper is to report the calculation results of the temperature and the thermal stress distributions of the permanent reflector by applying the computer aided design code I-DEAS and the finite element code ABAQUS. The present calculation is to estimate the high stress areas as a result of the new beam tube cutouts along the horizontal mid-plane of the reflector of the recent reactor upgrade project. These high stresses were not able to be calculated in the preliminary design analysis in earlier 60`s. The heat transfer boundary conditions are used in this redesigned calculation. The material constants and the acceptance criteria for the allowable stresses are mainly based on that assumed in the preliminary design report.

Chang, S.J.

1998-04-01T23:59:59.000Z

459

Manufacture and properties of continuous grain flow crankshafts for locomotive and power generation diesel engines  

SciTech Connect

The bulk of the large crankshaft production volume is associated with the medium speed diesel engine market. These engines have seen intense development to obtain higher power outputs without change in the physical size of the crankshaft and at the same time there has been continuing pressure to reduce costs. Fatigue and bearing normal wear are the major technical hurdles that threaten the crankshaft life, and measures for dealing with these issues are described. Continuous grain flow (CGF) crankshafts are responsible for the continued integrity of these enhanced power output engines and the production of these crankshafts is described. Comparisons are made with the older slab forging crankshaft production method. The demand for the medium speed diesel engine and its natural gas derivative is strong and supports an aggressive engine building industry serving locomotive, marine and power generation markets. This demand in turn relies on practical national standards that serve the needs of the engine builder, material supplier and the end user.

Antos, D.J.; Nisbett, E.G. [National Forge Co., Irvine, PA (United States)

1997-12-31T23:59:59.000Z

460

Inflow turbulence generation for eddy-resolving simulations of turbomachinery flows  

E-Print Network (OSTI)

A simple variant of recycling and rescaling method to generate inflow turbulence using unstructured grid CFD codes is presented. The method has been validated on large eddy simulation of spatially developing flat plate turbulent boundary layer. The proposed rescaling algorithm is based on the momentum thickness which is more robust and essentially obviates the need of finding the edge of the turbulent boundary layer in unstructured grid codes. Extension of this algorithm to hybrid RANS/LES type of approaches and for wall-bounded turbomachinery flows is also discussed. Results from annular diffuser with different inflow boundary layer characteristics is presented as an example application to show the utility of such an algorithm.

Arolla, Sunil K

2014-01-01T23:59:59.000Z

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461

The case for endurance testing of sodium-heated steam generators  

SciTech Connect

After operating pressurized water reactor (PWR) steam generators in U.S. nuclear plants during the past 33 years and plugging thousands of tubes and replacing numerous steam generators at immense costs, utility and steam generator designers are now confident that they can design, build, and operate PWR steam generators successfully. Deployment of liquid-metal fast breeder reactors (LMFBRs) will likely follow the same scenario if long-term testing is not performed and development completed prior to commercial deployment. A case is made for endurance testing of steam generators to be used in future LMFBRs.

Onesto, A.T.; Zweig, H.R.; Gibbs, D.C. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Division.); Carlson, R.D. (Argonne National Lab., IL (United States)); Rodwell, E. (Electric Power Research Inst., Palo Alto, CA (United States)); Kakarala, C.R. (Babcock and Wilcox Co., Barberton, OH (United States))

1993-08-01T23:59:59.000Z

462

An experimental investigation of turbine blade heat transfer and turbine blade trailing edge cooling  

E-Print Network (OSTI)

studies have investigated the fluid flow and heat transfer behavior in high Reynolds number flows. Blair [7,8] investigated the effect of grid generated turbulence on flat plate heat transfer. He showed that turbulent heat transfer coefficient in flow... AN EXPERIMENTAL INVESTIGATION OF TURBINE BLADE HEAT TRANSFER AND TURBINE BLADE TRAILING EDGE COOLING A Dissertation by JUNGHO CHOI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment...

Choi, Jungho

2005-02-17T23:59:59.000Z

463

Use of a Heat Flow Meter to Determine Active PCM Content in an Insulation  

SciTech Connect

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

464

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 governÖ (more)

Tang, Clement Chih-Wei

2011-01-01T23:59:59.000Z

465

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

466

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

467

Experimental investigation on heat transfer characteristics of magnetic fluid flow around a fine wire under the influence of an external magnetic field  

SciTech Connect

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

468

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

469

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 ďprimitive-variableĒ Navier-Stokes equations, the target macroscopic equations of the present model for the flow field are vorticityĖstream function equations, inspired by our recent work designed for nonrotating flows [S. Chen, J. TŲlke, and M. Krafczyk, Phys. Rev. E 79, 016704 (2009); S. Chen, J. TŲlke, 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 TŲlke; Manfred Krafczyk

2009-07-14T23:59:59.000Z

470

Blow-down tests in a sodium-heated steam generator tube. [LMFBR  

SciTech Connect

The design of steam generators for liquid metal fast breeder reactor (LMFBR) electric power plants is based on both normal load operation and plant transient conditions. Perhaps the most severe transient to which an LMFBR steam generator may be subjected is known as the water-side isolation and dump transient, often called the blow-down transient. LMFBR steam generators must be designed to accommodate a small but finite number of the blow-down transients. The purpose of this investigation was to perform a blow-down experiment in a well instrumented, full scale, single tube model of an LMFBR steam generator. The data may be used directly in steam generator design and as a validation point for steam generator mathematical models in plant transient computer codes.

France, D.M.; Carlson, R.D.; Chiang, T.

1983-01-01T23:59:59.000Z

471

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

472

NEXT GENERATION COMMERCIAL HEAT PUMPWATER HEATER USING CARBON DIOXIDE USING DIFFERENT IMPROVEMENT APPROACHES  

SciTech Connect

Although heat pump water heaters are today widely accepted in Japan, where energy costs are high and government incentives for their use exist, acceptance of such a product in the U.S. has been slow. This trend is slowly changing with the introduction of heat pump water heaters into the residential market, but remains in the commercial sector. Barriers to heat pump water heater acceptance in the commercial market have historically been performance, reliability and first/operating costs. The use of carbon dioxide (R744) as the refrigerant in such a system can improve performance for relatively small increase in initial cost and make this technology more appealing. What makes R744 an excellent candidate for use in heat pump water heaters is not only the wide range of ambient temperatures within which it can operate, but also the excellent ability to match water to refrigerant temperatures on the high side, resulting in very high exit water temperatures of up to 82√?¬ļC, as required by sanitary codes in the U.S. (Food Code, 2005), in a single pass, temperatures that are much more difficult to reach with other refrigerants. This can be especially attractive in applications where this water is used for the purpose of sanitation. While reliability has also been of concern historically, dramatic improvements have been made over the last several years through research done in the automotive industry and commercialization of R744 technology in residential water heating mainly in Japan. This paper presents the performance results from the development of an R744 commercial heat pump water heater of approximately 35 kW and a comparison to a baseline R134a unit of the same capacity and footprint. In addition, recommendations are made for further improvements of the R744 system which could result in possible energy savings of up to 20 %.

Chad Bowers; Michael Petersen; Stefan Elbel; Pega Hrnjak

2012-04-01T23:59:59.000Z

473

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 90ļ 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

474

New Li-ion Battery Evaluation Research Based on Thermal Property and Heat Generation Behavior of Battery  

Science Journals Connector (OSTI)

We do a new Li-ion battery evaluation research on the effects of cell resistance and polarization on the energy loss in batteries based on thermal property and heat generation behavior of battery. Series of 18650 cells with different capacities and electrode materials are evaluated by measuring input and output energy which change with charge-discharge time and current. Based on the re