CONJUGATE NATURAL-CONVECTION FROM AN ARRAY OF PROTRUDING HEAT-SOURCES

Coupled conduction and natural convection heat transfer has been inves tigated numerically for protruding heat sources mounted to one vertica l wall of a rectangular cavity. The heat sources simulate an array of computer chips mounted on a substrate of finite thermal conductivity. The back of the substrate and the horizontal walls of the cavity are a ssumed to be adiabatic, while the opposing vertical wall provides an i sothermal heat sink. The fluid Prandtl number and the heater/fluid the rmal conductivity ratio are fixed at 25 and 2350, respectively, corres ponding to a dielectric fluid (FC-77, manufactured try 3M Company) and silicon chips. With increasing modified Rayleigh number (10(4) less t han or equal to RaLz less than or equal to 10(9)), the cavity flow ap proaches boundary layer behavior, and more fluid penetrates the region s between protrusions. The effect of contact resistance between the he ater and substrate is shown to be small for R(th)'' less than or equal to 10 cm(2) degrees C/W. With decreasing substrate thermal conductivi ty [1.48 W/ (m K) less than or equal to k(s) less than or equal to 148 W/(m K)] fluid circulation decreases and the maximum heater temperatu res increase.