scholarly journals TAC3D: A GENERAL PURPOSE THREE-DIMENSIONAL HEAT TRANSFER COMPUTER CODE: MATHEMATICAL FORMULATIONS AND PROGRAMMER'S GUIDE.

1969 ◽  
Author(s):  
S Clark ◽  
J Del Bene ◽  
J Petersen
Author(s):  
Will Schreiber ◽  
John Kuo

Abstract The current paper describes a computer model designed to analyze the moisture transport in the unmelted, porous soil neighboring a convecting melt. The time-dependent fluid and heat flow in the soil melt is simulated implicitly using the SIMPLE method generalized to predict viscous fluid motion and heat transfer on boundary-fitted, non-orthogonal coordinates which adapt with time. TOUGH2, a general-purpose computer code for multiphase fluid and heat flow developed by K. Pruess at Lawrence Berkekey Laboratory, has been modified for use on time-adaptive, boundary-fitted coordinates to predict heat transfer, moisture and air transport, and pressure distribution in the porous, unmelted soil. The soil melt model is coupled with the modified TOUGH2 model via an interface (moving boundary) whose shape is determined implicitly with the progression of time. The computer model’s utility is demonstrated in the present study with a special two-dimensional study. A soil initially at 20°C and partially-saturated with either a 0.2 or 0.5 relative liquid saturation is contained in a box two meters wide by ten meters high with impermeable bottom and sides. The upper surface of the soil is exposed to a 20°C atmosphere to which vapor and air can escape. Computation begins when the soil, which melts at 1700°C, is heated from one side (maintained at constant temperatures ranging from 1700°C to 4000°C). Heat from the hot wall causes the melt to circulate in such a way that the melt interface grows more rapidly at the top of the box than at the bottom. As the upper portion of the melt approaches the impermeable wall it creates a bottle neck for moisture release from the soil’s lower regions. The pressure history of the trapped moisture is examined as a means for predicting the potential for moisture penetration into the melt. The melt’s interface movement and moisture transport in the unmelted, porous soil are also examined.


1994 ◽  
Vol 342 ◽  
Author(s):  
J. Vernon Cole ◽  
Karson L. Knutson ◽  
Klavs F. Jensen

ABSTRACTWe present a general purpose Monte Carlo method for the simulation of radiation heat transfer in rapid thermal processing (RTP) chambers. Three-dimensional mesh generation software is used to discretize the surfaces within the system, allowing the simulation of realistic chamber and reflector designs. An adaptive subdivision of the chamber geometry reduces the number of raysurface intersections which must be computed. The method models internal reflection, absorption, and transmission within participating media, and includes wavelength, temperature, and material dependent optical properties. Radiation heat transfer simulations are used to examine a reflector assembly, and to test the assumptions of optical wafer temperature measurement techniques.


1991 ◽  
Vol 113 (1) ◽  
pp. 40-49 ◽  
Author(s):  
Heiu-Jou Shaw ◽  
Wen-Lih Chen ◽  
Cha’o-Kuang Chen

In this paper, the mixed convective heat transfer phenomena in a three-dimensional channel with one heating-element is studied. A general-purpose computer program is developed to analyze the flow field and temperature distribution in the channel. In order to ensure the accuracy of result, numerical computation is performed by using the alternating direction implicit (A.D.I.) method based on the SIMPLER algorithm. This paper deals with fundamental heat transfer phenomena in “L.S.I.” package, which is used extensively in microelectronic equipment. The influences of Reynolds number and Grashof number on the Nusselt number of the heating-element are discussed. In order to make it easier for readers to understand the phenomena studied in this paper, three-dimensional streaklines and three-dimensional isothermal surfaces are presented.


Author(s):  
M M Jafari ◽  
G Atefi ◽  
J Khalesi ◽  
A Soleymani

The erosion of the hot regions in a gas turbine is one of the most important challenges encountered by the power plants. Though several numerical simulations of the problem have been reported so far, little is known to give accurate results. In this article, the thermoelastic behaviour of a gas turbine blade with internal steam-cooled channels positioned within a three-dimensional cascade configuration has been studied. A computer code based on the conjugate heat transfer method using the simultaneous solution of Navier–Stokes and heat transfer equations has been developed. From this study, the temperature distribution along with the stress values at high temperatures has been obtained. The blade parameters such as E, α, and K were considered to be a function of the temperature. In the previous works, usually only one or two of these parameters was considered as temperature dependent and the others constant. In this article, all the blade parameters, though making the equations highly non-linear, were considered as a function of temperature. The results have been compared with the available experimental data and a good agreement is observed. According to these findings, taking the temperature dependency of materials into account increases the estimations accuracy and brings the results closer to the reality.


Author(s):  
Tara Gallaway ◽  
Steven P. Antal ◽  
Michael Z. Podowski

This paper is concerned with the mechanistic modeling and theoretical/computational analysis of flow and heat transfer in future Generation-IV Supercritical Water Cooled Reactors (SCWR). The issues discussed in the paper include: the development of analytical models of the properties of supercritical water, and the application of full three-dimensional computational modeling framework to simulate fluid flow and heat transfer in SCWRs. Several results of calculations are shown, including the evaluation of water properties (density, specific heat, thermal conductivity, viscosity, and Prandtl number) near the pseudo-critical temperature for various supercritical pressures, and the CFD predictions using the NPHASE computer code. It is demonstrated that the proposed approach is very promising for future mechanistic analyses of SCWR thermal-hydraulics and safety.


2005 ◽  
Vol 127 (4) ◽  
pp. 508-514 ◽  
Author(s):  
Narendra Are ◽  
Miles Greiner ◽  
Ahti Suo-Anttila

Federal regulations (10CFR71) require radioactive material transport packages to safely withstand a 30min fully engulfing fire. The three-dimensional Container Analysis Fire Environment (CAFE-3D) computer code was developed at Sandia National Laboratories to simulate the response of massive packages to large fires for design and risk studies. These studies require rapid and accurate estimates of the package temperature distribution for a variety of package designs and fire environments. To meet these needs CAFE-3D links a finite element model that calculates the package response to the Isis-3D CFD fire model. ISIS-3D combines computational fluid dynamics with reaction chemistry and thermal radiation models to rapidly estimate the heat transfer from a fire. In the current work, parameters used in the fire model were determined. Simulations were then performed of a test that modeled the conditions of a truck-sized nuclear waste package in a regulatory fire under light wind conditions. CAFE-3D underestimated the ability of the wind to tilt the fire and deliver oxygen to the region above the fuel pool. However, it accurately and rapidly estimated the total heat transfer to the test object. CAFE-3D will become a more useful tool for estimating the response of transport packages to large fires once it has been benchmarked against a larger range of fire conditions.


Author(s):  
Alexander Grahn ◽  
Sören Kliem ◽  
Ulrich Rohde

This article presents the implementation of a coupling between the 3D neutron kinetic core model DYN3D and the commercial, general purpose computational fluid dynamics (CFD) software ANSYS-CFX. In the coupling approach, parts of the thermal hydraulic calculation are transferred to CFX for its better ability to simulate the three-dimensional coolant redistribution in the reactor core region. The calculation of the heat transfer from the fuel into the coolant remains with DYN3D, which incorporates well tested and validated heat transfer models for rod-type fuel elements. On the CFX side, the core region is modelled based on the porous body approach. The implementation of the code coupling is verified by comparing test case results with reference solutions of the DYN3D standalone version. Test cases cover mini and full core geometries, control rod movement and partial overcooling transients.


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