Thermal performance investigation of width-divergent tapered microchannel heat sinks

This study uses numerical analysis to examine the thermal performance of width-divergent tapered microchannel heat sinks. The influence of increasing channel width with different divergence ratios on the fluid flow and heat transfer characteristics of the tapered microchannels is investigated. In the proposed microchannels, the channel width increases in the flow direction while the channel height decreases. The fluid flow is single-phase, laminar, and incompressible. Ansys CFX is used to solve the governing equations in the solid and fluid domains simultaneously, and conservation of temperature and heat flux is applied to the solid-fluid interfaces. According to the findings, width-divergent tapered microchannels outperform parallel microchannels in terms of average heat transfer coefficient; however, the pressure drop is higher in width-divergent tapered microchannels. While the local heat transfer coefficient decreases in the flow direction in parallel microchannels, the acceleration of the flow due to the decrease in the channel cross-section causes an increase in the heat transfer coefficient downstream mid-length of the channel in width-divergent tapered microchannels. Results also reveal that the case with a lower divergence ratio has the lowest thermal resistance. Furthermore, by considering thermal and hydraulic performance, the case with a smaller divergence ratio has a higher heat transfer coefficient at the same pumping power.