Effect of fin shapes on flow boiling heat transfer with staggered fin arrays in a heat sink

Abstract

With the miniaturization development of electronic devices and the increase of unit heat flux, it is significant to design an efficient cooling system to ensure the general operation of the devices. In this work, two-phase flow boiling performance of staggered pin finned channels is analyzed by using the Mixture multiphase model. The influence of fin cross-section shape (circular, triangular, diamond and pentagonal) on flow boiling heat transfer, pressure drop, temperature uniformity in channels under different heat flux conditions are compared. Coolant Novec649 is used as the working fluid, and the mass flux is set to 1527 kg·m−2·s−1, the heat flux range is from 50 to 300 kW·m−2. Through numerical simulation, the results show that the average heat transfer coefficient increases in the order of circular, diamond, triangular and pentagonal finned channel. With the increase of heat flux, the average heat transfer coefficient for four kinds of pin finned channel slightly decreases, while the pressure drop all increases. Due to the large upstream surface area and asymmetrical vortices, the pressure drop is the highest and the temperature uniformity performs worst in the triangular finned channel. The circular finned channel represents the lowest pressure due to the streamline structure of circular fins, and pentagonal finned channel represents the most uniform wall temperature because the vortices around the fins are relatively strong and extensive. Comprehensively considering the heat transfer coefficient, pressure drop and temperature uniformity, the pentagonal finned channel is the most effective channel.