Investigation of thermal and hydraulic performance of MEMS heat sinks with zig-zag microchannels

Abstract

This work carries out an investigation on the performance of a MEMS microchannel heatsink with multiple zig-zag microchannels (MCHSzz). The heat sink is realized in silicon and uses water as the coolant. The study is conducted by employing Fluent module of Ansys Workbench. The performance of zig-zag and straight MCHS are compared for Reynolds number (Re) from 250 to 1500. The performance of the MCHS is quantified in terms of total thermal resistance (Rth) and pumping power (PPf) where Rth of zig-zag MCHS is better than that with straight microchannel; the enhanced thermal performance is achieved at the cost of increased PPf. Based on the cases studied in this work, it is observed that the relative change in Rth varied from 26% to 51% with increase in Re and the corresponding relative change in PPf varied from 40% to 120% with increase in Re. By employing zig-zag microchannels, it is possible to significantly reduce convective thermal resistance (Rth,cov), for a particular Re. Additionally, the influence of microchannel hydraulic diameter, orientation of microchannel, number of repeating units, and microchannel spacing are studied in this work. It is identified that the Rth and PPf over the considered range of Re decreased and increased, respectively, regardless of the geometric parameters. Additionally, Rth decreased with increase in geometric parameters for a specific Reynolds value until a threshold value beyond which no changes occur.

Keywords

• Electronics cooling
• MEMS heat sinks
• Heat transfer enhancement
• Thermal resistance
• Zig-zag microchannel