Experimental study of nucleate pool boiling of FC-72 on micro-pin-finned surface under microgravity

In order to effectively enhance the boiling heat transfer under microgravity, experiments were performed using micro-pin-finned structure as heater surface in subcooled nucleate pool boiling of FC-72 under short-term microgravity condition utilizing the drop tower Beijing. Micro-pin-fins with the dimensions of 30 × 60 μm2 (thickness × height) and the space of 30 μm were fabricated on the surface of square silicon with the dimensions of 10 × 10 × 0.5 mm3 by using the dry etching technique. The results were compared with previous published data of smooth chip both in normal gravity and microgravity conditions. The micro-pin-finned chip showed a considerable heat transfer enhancement in the nucleate boiling region with higher upper limit heat flux and lower mean heater surface superheat compared to chip S under microgravity condition. The high-efficient heat transfer performance of FC-72 on the micro-pin-finned surface is independent of gravity, which stems from the sufficient supply of fresh liquid to heater surface due to the capillary forces.