One-dimensional particle models for heat transfer analysis

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.

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

Journal of Thermal Science and Engineering Applications ◽

10.1115/1.4047163 ◽

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.

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Heat-Loss Calculations in a SCWR Fuel-Channel

18th International Conference on Nuclear Engineering: Volume 2 ◽

10.1115/icone18-30069 ◽

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.

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Errors in One-Dimensional Heat Transfer Analysis in Straight and Annular Fins

Journal of Heat Transfer ◽

10.1115/1.3450110 ◽

1973 ◽

Vol 95 (4) ◽

pp. 549-551 ◽

Cited By ~ 94

Author(s):

Wah Lau ◽

C. W. Tan

Keyword(s):

Heat Transfer ◽

Heat Transfer Analysis ◽

One Dimensional ◽

Annular Fins

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Combined Mode Heat Transfer Analysis Utilizing Radiation Scaling

Journal of Heat Transfer ◽

10.1115/1.3246982 ◽

1986 ◽

Vol 108 (3) ◽

pp. 626-632 ◽

Cited By ~ 9

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.

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Conjugate Heat Transfer Analysis of a Rotor Blade With Rib-Roughened Internal Cooling Passages

Volume 3: Turbo Expo 2005, Parts A and B ◽

10.1115/gt2005-68227 ◽

2005 ◽

Cited By ~ 7

Author(s):

Toshihiko Takahashi ◽

Kazunori Watanabe ◽

Takayuki Sakai

Keyword(s):

Heat Transfer ◽

Temperature Profile ◽

Rotor Blade ◽

Conjugate Heat Transfer ◽

Numerical Procedure ◽

Heat Transfer Analysis ◽

Internal Cooling ◽

Flow Calculation ◽

One Dimensional ◽

Rib Roughened

In order to predict temperature distribution of a rotor blade in a gas turbine on a rated condition, numerical analyses of conjugate heat transfer of the internally cooled blade were conducted. The target blade has rib-roughened internal cooling passages. Three-dimensional steady-state numerical analysis was executed with one-dimensional thermo-flow calculation of internal cooling by means of thermal conjugation of inside and outside fields of the blade, which consists of convection heat transfer around the blade, thermal conduction of the blade material and internal cooling. The one-dimensional thermo-flow calculation for the internal cooling was conducted with correlations of friction and heat transfer in rib-roughened channels, and combined with the 3-D analysis of the blade. The present prediction of the temperature profile on the blade coincides with the distinctive features of damage on actual ex-service blades. Moreover, that predicted temperature profile is in agreement with local temperature estimated by using the material of the actual ex-service blades. Influences of distribution of inlet gas temperature and of cooling conditions on the blade temperature were also investigated by using the present numerical procedure.

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