Second law analysis of an array of vertical plate-finned heat sink undergoing mixed convection

Second law analysis of an array of vertical plate-finned heat sink undergoing mixed convective heat transfer is investigated. The fluid flow and temperature fields are evaluated numerically solving the mass, momentum and energy conservation equations. The effects of Grashof number, inlet velocity, clearances, and fin spacing on entropy generation, Nusselt number, pumping power ratio and by-pass factor are presented. Total dimensionless entropy generation continuously decreases with clearances for all fin spacing, while Nusselt number shows an optimum value, especially at higher inlet velocities. There exists an optimum range of fin spacing at which Nusselt number is maximum for all Grashof numbers. The pumping power ratio shows significantly higher value for smaller fin spacing and at optimum fin spacing it decreases approximately by an order of magnitude. At optimum clearance, flow by-pass is significantly low.