High-Density Heat Removal in Micro Heat Sink Using Constructal Approach

Abstract

The paper seeks to remove a high-density heat flux of  using a microchannel heat sink constructed from a highly conductive aluminium substrate.  A numerical simulation and optimisation using multi-objective generic algorithm (MOGA) is carried out on a unit cell micro heat sink of fixed volume to obtain optimal design values. The objective is the maximisation of the global thermal conductance of the micro heat sink subject to manufacturing constrains. Computational fluid dynamic (CFD) code is used to solve the governing equations and finite volume method (FVM) to descretised the computational domain. Single-phase fluid (water) in a forced convection laminar condition is applied across the axial length of the micro heat sink. The Reynolds number of the fluid applied is in the range of 400 to 500. The optimisation is first performed on a microchannel with fixed axial length before the axial length is varied. The effect of hydraulic diameter, external aspect ratio and Reynolds number of fluid on peak temperature and minimised temperature is presented. The result of the optimisation shows that the global thermal conductance increases with increase in the velocity of the fluid (water) applied. The result obtained is validated and agrees with what is in the open literature.