Comparison between the thermal performance of single and two-layer microchannels inserted with micro pin fins
This paper presents a three-dimensional numerical study of steady, laminar, incompressible flow and forced convection heat transfer through a two-layer rectangular microchannel heat sink inserted with pin fins. The objective of the study was to optimise the geometric configuration of the combined two layer microchannel heat sink with micro pin fin inserts for a fixed solid volume so that the peak temperature within the configuration is minimised. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic code with a goal driven optimization workbench tool subject to global constraints. Effects of pressure drop on the minimised peak temperature and maximum thermal conductance for the fixed solid volume were reported. The thermal performance of the single and two-layer microchannel heat sink inserted with micro pin fins based on the minimised peak temperature and maximised global thermal conductance were compared and their results were reported. For a constant solid volume of 0.9mm3 and fixed length of 10mm, it was observed that while the performance of the single microchannel was improved with the micro pin fins, it was not the case with the two-layer microchannel. These results showed that inserting pin fins in a two-layer microchannel does not enhance the heat transfer when the length of the solid substrate is fixed. The thermal performance of the combined design when the axial length of the solid substrate was relaxed was also reported.