Thermodynamic Assessment of Microchannel Heat Sinks with Novel Sidewall Ribs

Abstract

An inadequate cooling associated with a straight microchannel heat sink for electronic components requires an improved thermal management with an acceptable cost of hydrodynamic deterioration by extending the effective heat transfer area. The present study is an attempt to numerically investigate the heat transfer and fluid flow characteristics in a microchannel heat sink having novel sidewall ribs configurations. The investigated geometric profiles include symmetrical ellipse-, trapezoid-, hydrofoil-, and rectangular-shaped ribs. A thermodynamics-based assessment has been conducted involving various evaluation parameters that include a friction factor ratio, a Nusselt number ratio, a thermal enhancement factor, transport efficiency, and entropy generation rates for a Reynolds number in the range of 100 to 1000. The predicted results supported the motivation of adding sidewall ribs to a microchannel heat sink with a significant heat transfer enhancement and a reasonable increase of pressure drop. The increased pressure drop leads to a higher pumping requirement for the flow system design, and is therefore assessed carefully with the evaluation parameters to yield a favorable configuration based on the overall performance for range of the Reynolds number . The results show that the sidewall ribs of a hydrofoil configuration are the best performers, yielding the least augmented entropy generation rates among all considered configurations.