Combined Mode Heat Transfer Analysis Utilizing Radiation Scaling

1986 ◽  
Vol 108 (3) ◽  
pp. 626-632 ◽  
Author(s):  
H. Lee ◽  
R. O. Buckius
Keyword(s):  
Heat Transfer ◽  
Scaling Laws ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Heat Transfer Analysis ◽  
Incident Intensity ◽  
One Dimensional ◽  
Flow Problems ◽  
Combined Mode ◽  
Good Agreement

Scaling laws have been formulated to predict the radiant heat flux in anisotropically scattering, one-dimensional planar media [1, 2]. The radiation portion of the problem is reduced to an equivalent nonscattering problem by the scaling. The same scaling laws are applied to problems when radiation is combined with other modes of heat transfer, requiring the solution of the energy equation for a temperature profile. The average incident intensity is accurately scaled by a multilayer approach. Results presented for radiation/conduction and the thermally developing Poiseuille flow problems show very good agreement between exact and scaled solutions for heat fluxes and temperature distributions.

Unsteady One-Dimensional Compressible Frictional Flow with Heat Transfer

1972 ◽  
Vol 14 (6) ◽  
pp. 365-369 ◽  
Author(s):  
R. I. Issa ◽  
D. B. Spalding
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Unsteady Flow ◽  
Hybrid Method ◽  
Numerical Procedure ◽  
Rectangular Grid ◽  
Paper Briefly ◽  
One Dimensional ◽  
Flow Problems ◽  
Good Agreement

The paper briefly describes a numerical procedure for solving problems of one-dimensional, unsteady, compressible, frictional flows with heat transfer. The procedure is based on the Hartree ‘hybrid’ method which combines the use of a rectangular grid with the use of characteristics. The main features of the procedure are its applicability and ease of adaptability to complex unsteady-flow problems. Another feature is the simplicity of its programming for a computer. Computations for flows in shock tubes are presented; they are in good agreement with previously published experimental data.

scholarly journals One-dimensional particle models for heat transfer analysis

2010 ◽  
Vol 260 ◽  
pp. 012005 ◽  
Author(s):  
H Bufferand ◽  
G Ciraolo ◽  
Ph Ghendrih ◽  
P Tamain ◽  
F Bagnoli ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Analysis ◽  
One Dimensional

scholarly journals A Hypothesis for the Redevelopment of Warm-Core Cyclones over Northern Australia

2008 ◽  
Vol 136 (10) ◽  
pp. 3863-3872 ◽  
Author(s):  
Kerry Emanuel ◽  
Jeff Callaghan ◽  
Peter Otto
Keyword(s):  
Heat Transfer ◽  
Thermal Diffusivity ◽  
Tropical Cyclones ◽  
Deep Layer ◽  
Heat Fluxes ◽  
Northern Australia ◽  
One Dimensional ◽  
Warm Core ◽  
Vertical Heat ◽  
Underlying Soil

Tropical cyclones moving inland over northern Australia are occasionally observed to reintensify, even in the absence of well-defined extratropical systems. Unlike cases of classical extratropical rejuvenation, such reintensifying storms retain their warm-core structure, often redeveloping such features as eyes. It is here hypothesized that the intensification or reintensification of these systems, christened agukabams, is made possible by large vertical heat fluxes from a deep layer of very hot, sandy soil that has been wetted by the first rains of the approaching systems, significantly increasing its thermal diffusivity. To test this hypothesis, simulations are performed with a simple tropical cyclone model coupled to a one-dimensional soil model. These simulations suggest that warm-core cyclones can indeed intensify when the underlying soil is sufficiently warm and wet and are maintained by heat transfer from the soil. The simulations also suggest that when the storms are sufficiently isolated from their oceanic source of moisture, the rainfall they produce is insufficient to keep the soil wet enough to transfer significant quantities of heat, and the storms then decay rapidly.

Design of a Plane-Type Bidirectional Thermal Diode

1988 ◽  
Vol 110 (4) ◽  
pp. 299-305 ◽  
Author(s):  
K. Chen
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Transfer Rate ◽  
Reverse Bias ◽  
Energy Utilization ◽  
Heat Transfer Analysis ◽  
Transfer Rates ◽  
One Dimensional ◽  
Plane Type ◽  
Solar Energy Utilization

The design of a plane-type, bidirectional thermal diode is presented. This diode is composed of two vertical plates and several fluid-filled loops with their horizontal segments soldered to the vertical plates. This invention is simple in construction and low in cost. The direction of heat transfer in the invented thermal diode can be easily reversed. These features of the present invention make it very attractive to solar energy utilization. Natural convection analysis for thermosyphon operations was adopted for heat transfer calculations of the fluid-filled loops. A one-dimensional heat transfer analysis was employed to estimate the heat transfer rate and ratio of heat transfer rates of the diode under forward and reverse bias.

Heat Transfer by Simultaneous Conduction and Radiation in an Absorbing Medium

1962 ◽  
Vol 84 (1) ◽  
pp. 63-72 ◽  
Author(s):  
R. Viskanta ◽  
R. J. Grosh
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Radiant Heat ◽  
Radiant Heat Transfer ◽  
Dimensional System ◽  
Parallel Plates ◽  
Approximate Methods ◽  
One Dimensional ◽  
Finite Distance ◽  
Transfer Problems

Heat transfer by simultaneous conduction and radiation in a thermal radiation absorbing and emitting medium is considered. Consideration is given to a one-dimensional system consisting of two, diffuse, nonblack, infinite, isothermal, parallel plates separated by a finite distance. The space between the plates is filled with a thermal radiation absorbing and emitting medium. The problem is formulated in terms of a nonlinear integro-differential equation and the solution is obtained by reducing it to a nonlinear integral equation. The numerical results are obtained by an iterative method. The temperature distributions and heat transfer are calculated. Two approximate methods for formulating radiant heat-transfer problems are presented and comparisons of the results are made with the most exact solution.

Forced Convection in a Porous Channel With Discrete Heat Sources

2000 ◽  
Vol 123 (2) ◽  
pp. 404-407 ◽  
Author(s):  
C. Cui ◽  
X. Y. Huang ◽  
C. Y. Liu
Keyword(s):  
Heat Transfer ◽  
Reynolds Numbers ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Porous Channel ◽  
Heat Sources ◽  
Nusselt Numbers ◽  
Discrete Heat Sources ◽  
Flow Through ◽  
Good Agreement

An experimental study was conducted on the heat transfer characteristics of flow through a porous channel with discrete heat sources on the upper wall. The temperatures along the heated channel wall were measured with different heat fluxes and the local Nusselt numbers were calculated at the different Reynolds numbers. The temperature distribution of the fluid inside the channel was also measured at several points. The experimental results were compared with that predicted by an analytical model using the Green’s integral over the discrete sources, and a good agreement between the two was obtained. The experimental results confirmed that the heat transfer would be more significant at leading edges of the strip heaters and at higher Reynolds numbers.

One-Dimensional Zonal Model for the Unsteady Heat Transfer Analysis in an Open Volumetric Air Receiver

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Gurveer Singh ◽  
Vishwa Deepak Kumar ◽  
Laltu Chandra ◽  
R. Shekhar ◽  
P. S. Ghoshdastidar
Keyword(s):  
Heat Transfer ◽  
High Heat ◽  
Operating Conditions ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
High Heat Flux ◽  
Unsteady Heat Transfer ◽  
Volumetric Heating ◽  
One Dimensional ◽  
Zonal Model

Abstract The open volumetric air receiver (OVAR)-based central solar thermal systems provide air at a temperature > 1000 K. Such a receiver is comprised of porous absorbers, which are exposed to a high heat-flux > 800 Suns (1 Sun = 1 kW/m2). A reliable assessment of heat transfer in an OVAR is necessary to operate such a receiver under transient conditions. Based on a literature review, the need for developing a comprehensive, unsteady, heat transfer model is realized. In this paper, a seven-equations based, one-dimensional, zonal model is deduced. This includes heat transfer in porous absorber, primary-air, return-air, receiver casing, and their detailed interaction. The zonal model is validated with an inhouse experiment showing its predictive capability, for unsteady and steady conditions, within the reported uncertainty of ±7%. The validated model is used for investigating the effect of operating conditions and absorber geometry on the thermal performance of an absorber. Some of the salient observations are (a) the maximum absorber porosity of 70–90% may be preferred for non-volumetric and volumetric-heating conditions, (b) the minimum air-return ratio should be 0.7, and (c) the smallest gap to absorber-length ratio of 0.2 should suffice. Finally, suggestions are provided for extending the model.

Heat-Loss Calculations in a SCWR Fuel-Channel

2010 ◽  
Author(s):  
Wargha Peiman ◽  
Eugene Saltanov ◽  
Kamiel Gabriel ◽  
Igor Pioro
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Nuclear Power ◽  
Heat Losses ◽  
Heat Transfer Analysis ◽  
Operating Pressure ◽  
Total Heat Loss ◽  
Fuel Channel ◽  
One Dimensional ◽  
Heated Length

The objective of this paper is to calculate heat losses from a CANDU-6 fuel-channel while modifying it according to the specified operating pressure and temperature conditions of SuperCritical Water-cooled Reactors (SCWRs). Heat losses from the coolant to the moderator are significant in a SCWR because of high operating temperatures (i.e., 350–625°C). This has adverse effects on the overall thermal efficiency of the Nuclear Power Plant (NPP), so it is necessary to determine the amount of heat losses from fuel-channels proposed for SCWRs. Inconel-718 was chosen as a pressure tube (PT) material and PT minimum required thickness was calculated in accordance with the coolant’s maximum operating pressure and temperature. The heat losses from the fuel-channel were calculated along the heated length of the fuel-channel. Steady-state one-dimensional heat-transfer analysis was conducted, and programming in MATLAB was performed. The fuel-channel was divided into small segments and for each segment thermal resistances of the fuel-channel components were analyzed. Further, the thermophysical properties of the coolant, annulus gas, and moderator were retrieved from the NIST REFPROP software. The analysis outcome resulted in a total heat loss of 29.3 kW per fuel-channel when the pressure of the annulus gas was 0.3 MPa.

Experimental and numerical simulation studies on heat transfer to calorimeters engulfed in diesel pool fires

2017 ◽  
Vol 35 (2) ◽  
pp. 156-176 ◽  
Author(s):  
Sudheer Siddapureddy ◽  
SV Prabhu
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Surface Temperature ◽  
Heat Fluxes ◽  
Numerical Code ◽  
Pool Fires ◽  
Steel Pipes ◽  
Adiabatic Surface ◽  
In Fire ◽  
Good Agreement

Characterization of heat transfer to calorimeters engulfed in pool fires is extremely important. To estimate the heat flux to the calorimeters, experiments are performed with horizontal stainless steel 304L pipes engulfed in diesel pool fires. The concept of adiabatic surface temperature is applied to predict the incident heat flux to horizontally oriented calorimeters engulfed in diesel pool fires. Plate thermometers are used to measure the adiabatic surface temperature for diesel pool fires. The estimated subsurface temperatures inside the steel pipes using the adiabatic surface temperature concept and the measured temperatures are in good agreement. Adiabatic surface temperature is also computed from fire simulations. The incident heat fluxes to the steel pipes engulfed in fire predicted from the simulations are found to be in good agreement with the experiments. The fire numerical code is validated against the 1 m pool fire experimental results of centerline temperature distribution and irradiances away from fire. A correlation is provided for the estimation of adiabatic surface temperature for large diesel pool fires. These results would provide an effective way for thermal test simulations.

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