Experimental Study on Thermal Performance of a Silicon-Based Micro Pulsating Heat Pipe

In this paper, an experimental investigation was conducted on the thermal performance of a silicon-based micro-pulsating heat pipe (SMPHP) using FC-72 and R113 as working fluids. The SMPHP, covering an area of 46 × 19mm², consisted of fourteen meandering trapezoidal channels with a hydraulic diameter of 352μm. The effects of gravity, filling ratio, and working fluids on the overall thermal resistance of the SMPHP were discussed. Experimental results show that gravity had an impact on the thermal performance of the SMPHP, and self-sustained oscillation could not be achieved at the horizontal orientation. The SMPHP worked as a true pulsating device when the filling ratio varied from 30% to 65%. For FC-72 and R113, there was an optimal filling ratio of 55% and 41%, respectively, for the best thermal performance of the SMPHP. As compared to the SMPHP with 0% filling ratio (or charged with the air), the thermal resistances of the SMPHP charged with FC-72 (at 55% filling ratio) and R113 (at 41% filling ratio) were decreased maximally by 7.24°C/W (or 56.5%) and 7.51 °C/W (or 59.7%), respectively. It is also found that the R113 was favorable for the operation of the SMPHP at lower power inputs, while FC-72 was favorable at relatively higher power inputs.