An experimental study of two-phase multiple jet cooling on finned surfaces using a dielectric fluid

In the present study, a multiple jet-cooling device for electronic components was investigated, using FC-72 as the working fluid. The nozzle plate, located 5 mm above the 12 x 12 mm(2) test surface, had 5 or 9 pores of 0.24 mm in diameter. The test surfaces included a smooth surface, two pin-finned surfaces and two straight-finned surfaces of 400 or 800 mu m fin height, 200 or 400 mu m fin thickness and gap width. The results showed that the heat transfer performance increased with increasing flow rate or increasing surface area enhancement ratio. The pin-finned surface of 800 mu m fin height, 200 mu m fin thickness and gap width yielded the best performance, which was about 250% greater than the smooth surface at 150 ml/min. Correlations of two-phase multiple jets, cooling in free and submerged states, are proposed based on the data at 50 degrees C saturation temperature, in the range of Re = 1655-8960, Bo = 0.024-0.389, area enhancement ratio = 1.0-5.32, jet spacing-diameter ratio (S/d) 13.7 and 20.6. The root mean square deviation of the prediction is 11.96% for the free jet data, and 9.08% for the submerged jet data. Thermal resistance of the best surface varied between 0.1 and 0.13 K/W at 150 ml/min flow rate in the range of 60-120W heat input. (C) 2011 Elsevier Ltd. All rights reserved.