Novel cooling approach in microchannel with fixed and variable fins configuration

Abstract

This paper explores a 3-D numerical simulation of a microchannel with a rectangular configuration. The objective of the study is to enhance performance by minimising thermal resistance within a fixed volume, considering two cases: fixed and variable fin configurations. A heat load of 438 W is applied to the bottom wall surface. Heat dissipation is achieved using forced convection under steady-state laminar conditions, with the fluid Reynolds number ranging from 100 to 150 and the convective air stream Reynolds number between 10 and 12. The fluid and heat fields are predicted using the finite volume (FVM) technique and a computational fluid dynamic (CFD) methodology. The results of the study indicate that minimised resistance decreased in both parallel and counterflow configurations, even with modifications to the fin characteristic profiles. Based on the numerical findings, at a maximum water pumping power of 0.23 W and an average air pressure drop of 0.706 kPa, the counterflow configuration with variable fin designs achieved the best performance, reducing minimised resistance by up to 33.3 %. This is followed closely by the parallel flow design, which achieved a 32.02 % reduction. In the heat sink with a fixed fin design, the fin height-to-length ratio is 1.75. In contrast, for the variable fin design, the fin length ratio ranges from 1.13 to 1.17 in parallel flow, with a height-to-length ratio between 1.29 and 2.23. In the counterflow configuration, the fin length ratio varies from 0.85 to 0.89. The numerical scheme is validated using both experimental and numerical data in open literature.