Geometric optimisation of multi-layered microchannel heat sink with different flow arrangements
This paper presents the use of the constructal design technique to optimise the geometry of a multilayered microchannel heat sink. The objective of this numerical investigation was to minimise the peak temperature of the solid substrate into which the microchannel was embedded. Parallel and counter-flow of fluid through the microchannel is considered in this study. The geometric optimisation of the microchannel was carried out using a computational fluid dynamic (CFD) code with a goal-driven optimisation workbench tool subject to global constraints. Optimal dimensions of the multi-layered microchannel in terms of the channel hydraulic diameter, channel aspect ratio, solid volume fraction, for the fixed solid volume that minimised the peak temperature and maximised the thermal conductance were reported. Results showed that as the pressure drop increased, the minimised peak temperature decreased and the maximum thermal conductance increased. When the number of layers of the microchannel was increased from two to three, the results of the thermal conductance became worse. For the design parameters used in this study, the two-layered stack microchannel with counter-flow arrangement was the best design in minimising the peak temperature and maximising the thermal conductance when the pressure drop was between 20 and 60kPa.