South African Journal of Science
versión On-line ISSN 1996-7489
This paper reports numerical optimization results for three-dimensional heat and fluid flow in a rectangular micro-channel heat sink using water as the cooling fluid. The conducting heat sink consists of silicon wafer. Numerical simulation was conducted on a unit cell which is a micro-channel heat sink with a fixed volume of 0.9 mm3 and a fixed axial length of 10 mm. Geometric optimization was carried out to determine the optimal aspect ratio of a unit cell of a heat sink that minimized the overall maximum temperature and thus maximized the overall global thermal conductance. The effect of total volume fraction of the silicon wafer on the optimal aspect ratio and minimized maximum temperature was also studied. Results show that as the pressure drop increases, the minimized peak temperature decreases, and suggests that there is an optimal allocation of solid volume fraction for a fixed pressure drop. The behaviour of the optimized volume is in agreement with the constructal design method, where the objective is to minimize the peak temperature, subject to the constraints of fixed total volume and solid (silicon wafer) material.