Numerical investigation of thermal performance of a combined heat sink with various microchannel shapes

The influence of channel shape on a combined heat sink of three different channel forms is investigated numerically in this work. The channel shapes considered were the trapezoidal, inverse trapezoidal and hexagonal microchannel shapes. The goal of this study was to compare and identify the combined microchannel shape that performed best under conditions of high uniform heat flux. The thermal performance of the combined heat sink was assessed using two criteria: lowest maximum temperature and lowest temperature elevation on the bottom of the combined heat sink where heat is applied. The uniform heat flux applied to the bottom of the combined heat sink was elevated from 100 𝑊/𝑐𝑚2 to1000 𝑊/𝑐𝑚2. For the maximum heat flux of 1000 𝑊/𝑐𝑚2and lowest pressure drop of 10kPa considered, in terms of temperature elevation on the bottom of the heat sink where heat is applied, the trapezoidal combined microchannel heat sink outperformed other channel shapes. When the minimized overall maximum temperature is considered, the hexagonal combined microchannel heat sink was the best combined heat sink.