Performance Enhancement Using Porous Slabs in a Jet Impingement Microchannel Heat Sink

Numerical study of a novel microjet impingement microchannel heat sink with porous media is proposed. Hydrothermal performance of the hybrid heat sink is investigated and compared with no porous media heat sink at Reynolds number 200 to 500 for several configurations of the porous slabs such as fully filled porous channel, bottom porous slab, side porous slab and slotted porous slabs in between two jets. Hybrid heat sink with fully filled porous media and slotted porous slab yielded lower wall temperatures; however, higher rise in pressure drop obtained. Furthermore, pressure drop is lowered remarkably with a reasonable rise in wall temperature in heat sink with slotted porous slabs. The changes in porous slab size affected abruptly the overall performance such as figure of merit. Thus, optimal size of the porous slabs as a function of Reynolds number is investigated for different configurations. The heat sink with 0.15 mm thick porous slabs at the base exhibited better overall performance at high Reynolds numbers, whereas at low Reynolds numbers, slotted porous slab of 0.5 mm length in the middle of impingements showed better overall performance. Generalized correlations of Nusselt numbers are developed for different cases helping optimize the heat sink design.