Silicon-Based Micro Pulsating Heat Pipe for Cooling Electronics

Abstract

This paper reports a micro-pulsating heat pipe (micro-PHP) fabricated in a silicon wafer that consists of trapezoidal microchannels with a hydraulic diameter of 394μm for electronic cooling applications. Electronic liquid FC-72 was used as the working fluid. To evaluate the maximum temperature reduction of the evaporator wall, experimental results of the vertical and horizontal-located micro-PHP at filling ratios ranging from 47% to 62% were compared with those measured from the empty micro-PHP (0% filling ratio). Results show that incorporating a micro-PHP as an integral part of silicon wafer could significantly decrease the maximum wafer temperatures and reduce the intensity of localized hot spots. At a power input of 6.0W, reductions in the evaporator wall temperature of about 32.3°C and 24.4°Cwere obtained for the micro-PHP at vertical and horizontal orientations, respectively. In addition, a CCD camera was employed to record the fluid movement inside microchannels and affirmed the existence of nucleation boiling and bulk circulation flow in the micro-PHP.