CFD study of slot jet impingement heat transfer with nanofluids

Abstract

We present a numerical investigation of hydrodynamic and heat transfer behaviors for Al2O3–water nanofluids for laminar and turbulent confined slot jets impingement heat transfer at nanoparticle volume fractions of 3% and 6%. A comparison of the nanofluid with the base fluid has been performed for the same Reynolds number and same jet inlet velocity. A single-phase fluid approach was used to model the nanofluid. Further, the thermo-physical properties of nanofluid were calculated using a recent approach. For the same value of Reynolds number, maximum increase in the average heat transfer coefficient at the impingement plate was found to be approximately 27% and 22% for laminar and turbulent slot impingements, respectively, for 6% volume fraction of nanofluid as compared to that of water. However, the pumping power curve showed a steep increase with the volume fraction with nearly five times increase in the pumping power observed for 6% volume fraction nanofluid. Further, the energy-based performance was assessed with the help of the performance evaluation criterion (PEC). PEC values indicate that nanofluids do not necessarily represent the most efficient coolants for this type of application. Moreover, at the same jet inlet velocity, a reduction in the heat transfer coefficient of 7% and 20% was observed for nanofluid as compared to base fluid for laminar and turbulent flows, respectively.