A topology optimization based design of a liquid-cooled heat sink with cylindrical pin fins having varying pitch

Abstract

An improved internal structure of a liquid-cooled heat sink has been proposed numerically and experimentally. The initial motivation is based on the results of thermal and fluid-flow topology optimization, which tends to produce a porous region despite suppression through the numerical scheme. The topology optimization was conducted using a Finite-Volume (FV) based procedure with a simplified sensitivity analysis as well as the globally convergent method of moving asymptotes (GCMMA) algorithm. The Spalart-Allmaras turbulence model was modified to handle the varying solid geometry in the topology optimization. As the result of multi-objective topology optimization showed a tendency towards the porous geometry inside the heat transfer domain, new models for the internal structure were proposed: a multi-layered porous medium with metal foam and varying-pitch cylindrical pin-fin structures. An experimental rig was developed for experimental validation of the proposed idea. The results shows that the varying-pitch cylindrical pin-fin structure inside the heat sink has advantages in heat transfer, pressure drop, and the manufacturability. Details of the numerical procedure and the experimental results are summarized in both quantitative and qualitative aspects.