Heat transfer performance of a circuit cooling heat sink with FC72 flow boiling.

An experimental study on a heat sink flow boiling heat transfer was performed to investigate the cooling performance of the heat sink which was designed to cool down electronic components such as central or graphic processing units. An experimental apparatus with a closed loop was made and the working fluid was FC72. The test section consisted of heat sink with fins and heaters which simulated heat dissipation in electronic components. Also, a heat sink without fins was manufactured to investigate the fin effects. The cooling area was 40×50 mm. The test was performed at the range of mass fluxes of 100 and 150 kg×m−2×s−1 and at the saturation pressure about 150 kPa. The heating was controlled at the ranges of 50, 100 and 200 W. The conditions at the test section inlet were regulated from subcooled states to saturation states with high vapor qualities. The measured convection heat transfer coefficients showed that they significantly changed with the variation of vapor quality and heat flux. Form the measured data, it can be concluded that both of nucleate boiling heat transfer mechanism played an important role at the flow boiling in the heat sink. The average heat transfer coefficients in the heat sink were up to 4 times higher at saturation state than those at liquid phase state. The cooling performance of the heat sink with fins was about 100% higher than that of the heat sink without fins at single and liquid to vapor phase change flow conditions.