Parametric study of heat transfer performance including entropy generation of microchannel heat sink with fan cavity and different rib structure

Abstract

This numerical study investigates the simultaneous application of axial wall conduction effect and entropy generation minimization as two principles to identify heat transfer performance in a microchannel heat sink with fan cavity and ribs. In this conjugate analysis, three different materials for a microchannel heat sink considered are silicon, aluminium, and copper. In addition to the fan cavity (F), effects of different rib configurations arranged symmetrically inside the fan cavity, that is, backward triangle rib (FB), rectangular rib (FR), forward triangle rib (FF), and diamond rib (FD) with Reynolds numbers ranging from 136 to 588 are studied. The comparative study between silicon and copper in terms of local wall and bulk fluid temperatures, increment in solid wall to fluid thermal conductivity ratio within the range (247.07 < k_sf< 669.44), local Nusselt number (Nu _x ), axial conduction number (M), and entropy generation number (N_s,a) were furnished and examined. Structural optimization is performed on diamond rib configuration geometrical parameters to observe entropy generation number and wall conduction effects trend as thermal performance is greatly improved to 2.49, at the lowest N_s,a to 0.31 at Re 391.47, with copper in the back to back cavities case. However based on the numerical results, comparative importance of axial wall conduction effect consideration in the present design of microsink, silicon is showing best results in overcoming at Re 588.4, consistently in all optimization cases.