Thermal design of a novel heat sink cooled by natural convection with phase transition in the series loop

In this paper, a novel heat sink, cooled by natural convection, with phase transition in the circulation loop was designed, and the heat sink was applied on averaging temperature and cooling the electronic equipment. The working fluid in the heat sink was driven by the capillary pump. Numerical simulations were performed, to study the heat transfer performance of two systems with various heating power, filling ratios and refrigerants. The influences of above elements on temperature uniformity of two systems were also studied and the thermal performances of two systems were compared. The volume of fluid (VOF) model was utilized to simulate fluid motion in ANSYS FLUENT. The simulation results indicate that the temperature differences of the system comprising two substrates (system 1) are very small under suitable filling ratio conditions, and the thermal performance of system 1 is preferable to the system comprising one substrate (system 2) at the same volume. Besides, the simulation results also show that the system using R245fa possesses excellent temperature uniformity for the same filling ratio and heating power. Finally, the experiments were investigated and the experimental results proved the correctness of the theoretical model.