TURBULENT NATURAL-CONVECTION COUPLED WITH THERMAL-RADIATION IN LARGE VERTICAL CHANNELS WITH ASYMMETRIC HEATING

Numerical and experimental investigations on turbulent natural air con vection coupled with thermal radiation have been performed in a vertic al rectangular channel with one-sided heated wall. A radiation model h as been developed with two new features: an analytical method for comp uting the view factor and the macro-elements method for improving the numerical efficiency. Numerical studies have shown that the CFD code F LUTAN combined with the radiation model developed is an efficient and accurate numerical tool to investigate the flow and heat transfer beha viour in systems considered. It has shown that at intermediate and hig h wall emissivities thermal radiation contributes significantly to the total heat transfer by natural air conviction, even at low temperatur es of the heated wall. Based on the experimental and numerical results the following semi-empirical correlation has bene developed for descr ibing the heat transfer of turbulent natural convection coupled with t hermal radiation in a vertical, rectangular channel with one-sided hea ted wall: Nu(t) = 0.1.Ra-1/3{1+(1+2.l)0.919.R-s/1+0.513.R-s}. (C) 1998 Elsevier Science Ltd. All rights reserved.