Suppressing free convection from a flat plate with poor conductor ribs

An experimental and numerical analysis is performed to investigate the effe ct of attaching poor conducting ribs on a vertical heated flat prate. Accor dingly, a test cell is constructed and a mathematical model is developed. T he ribs are made of a poor conducting material (plexiglass). The present wo rk is intended to study the suppression of free convection from a vertical plate with ribs attached on the surface. The effects of rib height to span ratio and Rayleigh number are investigated experimentally and numerically f or air as the working fluid. It has been found that adding ribs an the surf ace can reduce the rate of free convection heat transfer by as much as 75% compared with a bare plate. Rather complex recirculatory flow patterns are predicted in the space between the ribs at high Rayleigh numbers. (C) 1998 Elsevier Science Ltd. All rights reserved.