Heat dissipation and fluid flow in micro-channel heat sink equipped with semi-elliptical pin-fin structures: A numerical study

Abstract

Effective thermal management and temperature regulation are crucial for the optimal performance and safety of miniaturized modern electronic, electrical, and electrochemical devices, as they are prone to overheating. Currently, micro-pin fins combined with micro-channel heat sinks have proven to be highly efficient in dissipating large amounts of heat in compact sizes, making them widely used in electronic cooling systems. In the quest to enhance the thermohydraulic performance of Microchannel Heat Sinks (MCHSs), a significant focus is placed on modifying their geometric design. This study specifically explores the designing innovative semi-elliptical pin-fins (SEPFs) with aspect ratios (Ψ = 0.36, 0.49, 0.64, 0.81, 1.00) within the flow passage of the MCHS to examine how geometric factors influence heat transfer and fluid flow behavior. Alternate arrangement of SEPFs have been placed in MCHS to induce uneven flow turbulence in areas with low or no turbulence, leading to a comparatively higher heat dissipation rate. A three-dimensional model is used for this analysis. The MCHS featuring a semi-elliptical pin-fin is numerically simulated using Ansys Fluent. The Silicon MCHS, exposed to a heat flux of 1.0 × 106 W/m2, is cooled with water as heat transferring fluid within a Reynolds number (Re) range of 100 to 900. The integration of SEPF leads to a noticeable improvement in heat transfer efficiency compared to traditional MCHS, due to the increased convective surface area and flow turbulence. However, the effects of flow disturbances and confluence tend to overshadow the heat transfer enhancement. While the use of SEPF enhances the heat removal rate, it also results in an increase in pressure drop. It has been shown that the overall Thermal-Hydraulic Performance Parameter (THPP) reaches its maximum value of 1.41 for the Semi-Elliptical Pin-Fin (SEPF) configuration with an aspect ratio (Ψ) of 1.0 at a Reynolds number (Re) of 300. Conversely, the minimum value of THPP is observed for the SEPF configuration with Ψ = 0.36 at Re = 900.