Fabrication and evaluation of a slicon-based micro pulsating heat spreader

Abstract

A silicon-based micro pulsating heat spreader (MPHS) was fabricated and its thermal performance was experimentally evaluated. The width and height of the channel are 1 mm and 0.4 mm, respectively. The MPHS has length of 50 mm, width of 15.5 mm, and thickness of 1.5 mm. Ethanol was used as a working fluid. The MPHS achieved maximum effective thermal conductivity of 600 W/m K and a maximum heat transport capability of 4 W. In order to investigate the oscillating flow characteristics, the frequency and the amplitude of the liquid oscillation were measured. As the input power increases, the frequency and the amplitude are increased, which results in an increase in the thermal performance of the MPHS. The effective thermal conductivity was evaluated from a theoretical model in which the thermal performance of the MPHS is assumed to be similar to that of oscillating flow in a channel completely filled with liquid. When the input power is low, the calculated values are in close agreement with the measured values. When the input power is high beyond 2 W, the measured values are slightly higher than the calculated values, which is due to the contribution of heat transport by phase change. The MPHS transports heat mainly by liquid oscillation and the contribution of latent heat transport increases with increasing input power; however, the effect of the latent heat transport is not significant.