Numerical analysis of effect of nanofluid and fin distribution density on thermal and hydraulic performance of a heat sink with drop-shaped micropin fins

In the present study, the effect of nanofluid and distribution density of fin on thermal–hydraulic performance of a heat sink with drop-shaped micropin fins is investigated. Reynolds number is defined based on maximum flow velocity and varies in range of 100 ≤ Re_D ≤ 200 for which, in this range, the flow is laminar and steady. The fins are arranged in two configurations: in-line and staggered. Al₂O₃–water and CuO–water nanofluids with volume fraction of 1% and 4% and Ag₂O–water nanofluid were used to validate the present study. The results showed that using drop-shaped fins instead of circular-shaped fins increases the outlet temperature by 0.6% and decreases the pumping work by 13.3%. Moreover, using Al₂O₃–water nanofluid instead of pure water results in outlet temperature and pump work increases of 0.4% and 1%, respectively. Comparing results of different configurations showed that with low number of fin density, staggered arrangements provide higher outlet temperature than in-line arrangement. However, for moderate fin density, in-line arrangements result in higher outlet temperature, and in all fins distribution density, staggered arrangements need higher pump work compared to in-line arrangements.