STEADY-STATE INVESTIGATION OF VAPOR-DEPOSITED MICRO HEAT-PIPE ARRAYS

An experimental investigation of vapor deposited micro heat pipe array s was conducted using arrays of 34 and 66 micro heat pipes occupying 0 .75 and 1.45 percent of the cross-sectional area, respectively. The pe rformance of wafers containing the arrays was compared with that of a plain silicon wafer. All of the wafers had 8 x 8 mm thermofoil heaters located on the bottom surface to simulate the active devices in an ac tual application. The temperature distributions across the wafers were obtained using a Hughes Probeye TVS Infrared Thermal Imaging System a nd a standard VHS video recorder. For wafers containing arrays of 34 v apor deposited micro heat pipes, the steady-state experimental data in dicated a reduction in the maximum surface temperature and temperature gradients of 24.4 and 27.4 percent respectively, coupled with an impr ovement in the effective thermal conductivity of 41.7 percent. For waf ers containing arrays of 66 vapor deposited micro heat pipes, the corr esponding reductions in the surface temperature and temperature gradie nts were 29.0 and 41.7 percent, respectively, and the effective therma l conductivity increased 47.1 percent for input heat fluxes of 4.70 W/ cm(2). The experimental results were compared with the results of a pr eviously developed numerical model, which was shown to predict the tem perature distribution with a high degree of accuracy, for wafers both with and without the heat pipe arrays.