Confined Jet Array Impingement Cooling Using NEPCM Nanofluids

The confined jet array impingement cooling using NEPCM (nano-encapsulated phase change material) slurry was investigated numerically using a homogeneous model based on effective heat capacity method. The nanofluids consists of the carrier fluid of polyalphaolefin (PAO) and the NEPCM particles of Polystyrene shell and paraffin core. The distributed slot jet array with the jet width W=100 μm, confinement height H=300 μm, jet-to-jet distance S=400 μm was investigated at first under different jet velocity, inlet temperature and NEPCM volumetric concentration. It was found that for a fixed jet velocity, there is an optimal NEPCM volumetric concentration and an optimal inlet temperature to achieve the maximum average heat transfer coefficient. The larger the jet velocity, the higher the optimal NEPCM concentration and the closer the optimal inlet temperature to the midpoint of melting temperature range of PCM where the peak of effective heat capacity achieves. The local heat transfer on the heating surface under the exit slot is the weakest, because of stagnant zone formed by the head-to-head collision of the two adjacent jets. The pressure drop and average heat transfer coefficient of six jet arrays with different H/W (=2, or 3) and S/W (=3, 4 or 5) were also compared.Copyright © 2016 by ASME