Abstract:

This paper presents an experimental investigation on the thermal performance of a micro pulsating heat pipe (MPHP)embedded on a silicon wafer with the trapezoidal cross section having a hydraulic diameter of 352 μm. With FC-72 and R113 as working fluids, the effects of gravity, filling ratio, and working fluid on the thermal performance of MPHP are discussed. Experimental results show that the MPHP functions well at its hydraulic diameter or a Bond number about 0.45. Gravitational effect on the thermal performance cannot be ignored although it is small in comparison with the surface tension effect. At an inclination angle larger than 10°, the MPHP works as a true pulsating device when the filling ratio varies from 30% to 65%, enhancing the heat transfer capacity effectively. For FC-72 and R113, the optimal filling ratio is 55% and 41%, respectively, for the best thermal performance of the MPHP. The heat transfer capability of the MPHP is significantly enhanced and the thermal resistances is reduced up to about 56. 5% (FC-72)and 59. 7% (R113)at a power input of 8.5 W with the corresponding optimal filling ratios when compared to the unfilled MPHP(0 filling ratio).It is also found that R113 is fit for the MPHP at lower heat loads, while FC-72 is favorable at relatively higher heat loads.

摘要：

研究了当量直径352 μm梯形截面微型硅基振荡热管的传热特性。以FC-72和R113为工质，讨论了重力、充液率和工质等因素对微热管传热性能的影响。实验结果发现，在该通道直径或Bond数为0.45时微热管可以有效振荡运行，虽然此时表面张力作用显著，但不能忽略重力对其传热性能的影响。当倾角大于10°、充液率介于30%和65%之间时微热管具有振荡运动的特征，可显著增强传热效果。微热管分别以FC-72和R113为工质时，对应的最佳充液率分别为55%和41%