Enhancing heat transfer efficiency and entropy generation minimization in Micro-Channel Heat Sinks through pillar spacing and diameter optimization

Abstract

Micro-Channel Heat Sinks (MCHSs) have several applications and notable efficiency in the cooling of electronic devices. In the present work, Micro-Channel Heat Sinks (MCHSs) with different number of inserted pillars are investigated extensively in the purpose of improving the efficiency of microstructures insertion in MCHS. A Computational Fluid Dynamics (CFD) analysis was carried out in ANSYS Fluent 19.0. The study focused on a single micro-channel, with simulations performed for Reynolds number ranging from 300 to 740. Effects of both the spacing between the pillars and their diameter was discussed, pillar spacing ranging from 2.5 to 97.5 times the pillar diameter (with pillar numbers from 5 to 150), and a pillar diameter ranging from 2/8 to 5/8 times the channel width (Wch). These two parameters have shown a serious impact on thermal, thermo-hydraulic performance and entropy generation of the MCHS. Heat transfer was augmented up to four-fold by inserting pillars into the MCHS. The highest Nusselt number was achieved with configuration P75 with a relative spacing around 5.2 (Ss=5.2×Dp), while the highest performance enhancement coefficient (PEC) was obtained for the 3/8×Wch diameter of configuration P50. Proposed insertion criterions enhance Nusselt number and PEC of MCHS with inserted pillars and provides design parameters for any further use of pillars in MCHS.