Entropy generation analysis of a dual-height plate-fin heat sink with Nanofluid coolant applying two-phase mixture model

Abstract

In this work, the two-phase mixture model is applied to solve the velocity field, the pressure field and obtain the entropy generation rates in a dual-height plate-fin heatsink. The governing equations were solved using the second-order upwind discretization scheme as well as SIMPLE scheme used in coupling the pressure and velocity fields. The Re, nanoparticle concentration (ψ), secondary fin height (hsf), and fin spacing (dsf) were considered within the ranges of 500-2000, 0%-1%, 5 mm-17.5 mm, and 0.25 mm-0.5 mm, respectively. The results demonstrated that S˙th almost decrease by 30% as hsf increases from 5 mm to 17.5 mm. The increase in hsf escalates S˙fr by 308% and 238% at Re numbers of 500 and 2000, respectively. In addition, the escalation of Re from 500 to 2000 increases S˙fr by 2125% and 1748% for hsf 5 mm and 17.5 mm, respectively. The fin spacing analysis revealed that the lowest S˙th and highest S˙fr belong to dsf=0.5 mm. The lower the dsf the higher the backward flow and mixing flow at the heatsink outlet, thereby delay in flow passage and intensification of S˙th and S˙fr.