Shigeyuki Sasaki

Distribution of heat transfer coefficients from small surfaces cooled with submerged jets of fluorocarbon liquid determined by inverse analysis of heat conduction

Convective boiling from small surfaces with submerged impingement of fluorocarbon liquid is investigated for high-performance cooling systems of electronic devices. The local heat transfer coefficients from silicon heaters in submerged impingement are measured by two independent techniques. The silicon heaters used for this measurement are constructed of many cells which can independently generate heat on one side of the heater and are cooled on the other side. Each cell also contains a sensor to measure the temperature, One of the independent techniques we use is to control the distribution of the heater power to produce a uniform temperature. With this technique, the variation of the heat flux distribution between each side of the heater caused by the heat conduction can be eliminated and the heat transfer coefficients measured more accurately. The second technique we use is inverse analysis. Inverse analysis is used to correct the effect of heat conduction in the heater and to determine the distribution of heat transfer coefficients on the cooling surface. The distribution of heat transfer coefficients determined with these techniques agreed well with the equations used to describe the convective boiling.