Hydrothermal Investigation of the Performance of Microchannel Heat Sink with Ribs Employed on Side Walls

Abstract

Abstract In the present study, conjugate heat transfer and fluid flow performance of microchannel heat sink has been investigated using dimensionless parameters. Novel ribs of four different types are introduced on the side walls of channel, which include trapezoidal ribs, rectangular ribs, hydrofoil ribs, and elliptical ribs. The performance evaluation has been conducted by comparing friction factor (f), Nusselt number ( N u Nu ), fluid bulk temperature ( T f {T_{f}} ), wall shear stress (τ), field synergy number ( F c Fc ), irreversible heat loss ( Q d {Q_{d}} ), and Bejan number ( B e Be ) in a Reynolds number, ranging from Re = 100 \mathit{Re}=100 to Re = 1000 \mathit{Re}=1000 . The results revealed that the addition of these novel ribs are helpful in improving the overall thermal and hydraulic performance of microchannel heat sink. From the results of Bejan number, it has been revealed that more than 96 % of losses are because of heat transfer. However, at low Reynolds number, the frictional losses can be neglected, because of very low fluid velocity. Moreover, it has been revealed that synergetic relation between velocity and temperature gradient becomes weaker at higher Reynolds number. Furthermore, it is clear from this study that elliptical ribs performed better in thermal aspects, whereas hydrofoil ribs performed better at hydrodynamic aspects.