Development of a Compact Micro Pulsating Heat Pipe

A compact micro pulsating heat pipe was developed and tested to investigate thermal performance. Micro Flat Plate Pulsating Heat Pipe (FP-PHP) was fabricated using DRIE MEMS technique. A total of 10 parallel interconnected rectangular channels forming a meandering closed loop are engraved on the silicon wafer with a thickness of 1 mm. The top of the silicon wafer was covered by a transparent glass plate (#7740PyrexTM) with a thickness of 0.5 mm to allow visualization of the internal thermo-hydrodynamic behavior in the PHP. The overall FP-PHP has length of 50 mm, width of 15.5 mm, and thickness of 1.5 mm, respectively. The width and height of the engraved rectangular channel is 1 mm and 0.6 mm and the hydraulic diameter is 0.75 mm. The ethanol is used for working fluid. The results show that the FP-PHP without working fluid has thermal resistance of 17 °C/W and the FP-PHP with working fluid of filling ratio of 50% has thermal resistance of 4 °C/W. In other words, the FP-PHP has effective thermal conductivity of 650 W/mK which is about 1.6 times as much as of that of the Copper (k_eff = 400 W/mK). Therefore the developed FP-PHP can be used as compact high performance electronic cooling system.