Enhanced Boiling Heat Transfer by Using Micro-Pin-Finned Surface in Three Different Test Systems

Abstract

For efficiently cooling electronic components, experiments were conducted to study heat transfer performance of FC-72 over a silicon chip with micro-pin-fins in three different test systems including pool boiling, natural circulation flow boiling, and forced flow boiling. A smooth chip (chip S) and a micro-pin-finned chip having fin thickness of 30 μm and fin height of 60 μm (chip PF30-60) were tested. The micro-pin-fins were fabricated on the surface of square silicon chip (10 × 10 × 0.5 mm3) by use of dry etching technique for enhancing boiling heat transfer. The experiments were conducted at fluid velocities of 0.5 and 1 m/s for the forced flow boiling and the liquid subcoolings of 25 and 35 K for all three test systems. With regard to the three test systems, the micro-pin-finned surface shows a considerable heat transfer enhancement compared to the smooth surface and shows a sharp increase in the critical heat flux (CHF). For the same chip, the boiling curves are almost the same for the pool boiling and the natural circulation flow boiling, while the boiling curves shift toward a smaller wall superheat for the forced flow boiling. The critical heat flux was the highest for the forced flow boiling at a fluid velocity of 1 m/s.