Novel cooling technique in double-layer microchannel heat sink with fins

This paper presents the numerical optimisation of a two-layer heat sink incorporating fins on the top plate to enhance heat transfer. The objective is the maximisation of the thermal conductance. The optimisation procedure employs a multi-objective genetic algorithm using an Optimal Space-Filling Design (OSFD). The analysis is conducted over a cooling channel with a width of 0.032 mm and a length of 0.090 mm, while the channel diameter is fixed at 0.047 mm. A high-density heat flux from a microelectronic device is imposed on the system, and water and air with Reynolds numbers ranging from 300 to 500 and 6 to 14 are considered under a forced convection laminar flow regime. Finite volume and computational method are used to discretised and solve for fluid and heat dissipation in the system. The results from the simulation shows that the design with parallel flow in upper and lower channels (PULC) is superior, the counter flow in fin domain (CFD) and PULC has the lowest outlet temperature of 312.5 K. However, in the optimised designs the performance is 25.96% higher in PULC with Nusselt number of 32.1 above other configurations at a pumping power of 0.007 W, while the increase in heat transfer coefficient in the optimised designs is 40.36% in favour of PULC. The study further discovered that the film temperature in PULC is 1.23% lower than other configurations. The enhanced designs outperformed the baseline with an error margin of 1.8%, and the study is validated using both experimental and numerical data.