Improving performance of single and double-layered microchannel heat sinks by cylindrical ribs: A numerical investigation of geometric parameters

Abstract

In this study, 3-Dimensional numerical simulations are carried out to characterize the laminar fluid flow as well as forced convection heat transfer through novel designs of single and double layered microchannel heat sinks with cylindrical ribs. The three designs investigated in this study include: single-layered (SL) microchannels, double-layered-design 1 (DL-D1) microchannels and double-layered-design 2 (DL-D2) microchannels. Effects of different geometric parameters including rib pitch (0.5 mm ≤ P ≤ 1 mm) and radius (0.005 mm ≤ R ≤ 0.025 mm) are investigated. Based on the results, incorporation of the cylindrical ribs leads to chaotic advection and re-development of thermal boundary layers, which in turn results in a significant enhancement in heat transfer coefficient. Accordingly, reducing the rib pitch has a greater effect on improving the hydrothermal performance than increasing radius. Also, Double-layered microchannels (design 1 and 2) achieved 30–60% higher convection heat transfer coefficient in comparison with single-layered microchannels heat sinks. By increasing mass flow rate, the double-layered-design 1 microchannels led to higher thermal performances compared to single-layered and double-layered-design 2. Finally, the ribbed microchannels with the geometric characteristics of P = 0.5 and R = 0.025 are found to have the best performance.