Thermal management strategy for electronic chips based on combination of a flat-plate heat pipe and spray cooling

Abstract

With the rapid development of electronic technology, the required heat dissipation capacities of electronic chips are increasing. In this study, a thermal management strategy for electronic chips based on a combination of a flat-plate heat pipe (FPHP) and spray cooling was designed to improve the heat dissipation performance of the condensation section of the heat pipes. Experiments were conducted to investigate the start-up characteristics of the FPHP, as well as the effects of the inlet temperature and the spray flow rate on the overall heat transfer performance. The best comprehensive performance of the FPHP and spray cooling was obtained when the heat flux was 20–40 W/cm2. In this heat-flux range, the heat pipe had the lowest thermal resistance and the highest thermal conductivity, and the corresponding spray heat transfer coefficient was 168.4 kW/(m2•K), which was significantly higher than those for traditional air-cooled (0.02∼0.1 kW/(m2•K)) and water-cooled radiators (1∼10 kW/(m2•K)). Within a certain range, a higher inlet temperature corresponded to a shorter start-up time of the heat pipe, and the effect of inlet temperature on the heat transfer uniformity of the heat pipe was negligible. Moreover, when the heat flux was less than 30 W/cm2, increasing the inlet temperature would help increase the temperature difference between the evaporation surface and the condensation surface of the heat pipe, and improved the heat transfer performance of FPHP. But when the heat flux was greater than 30 W/cm2, the higher the inlet temperature, the higher the amount of steam in the vapor chamber, the greater the thermal resistance, and the worse the heat transfer performance of FPHP. Increasing the inlet temperature of the cooling medium caused the droplets to vaporise at the entrance of the nozzle in advance, weakening the dissipation effect of the spray cooling. The combination of the heat pipe and spray cooling provides a novel idea for electronic thermal management technology, that is, using two or more cooling technologies to adapt to diverse applications.