Experimental and Numerical Study of Multiple Free Jet Impingement Arrays with Al2O3-Water Nanofluid

Abstract

Nanofluid jet impingement cooling is commonly used in many industrial applications due to its capability to dissipate large amounts of heat fluxes from surfaces. In this paper, an experimental and numerical investigation on heat transfer enhancement and fluid flow characteristics of multiple free surface jet impingement using water and Al2O3-water nanofluid as coolants were described. The effects of changing holes arrangement, nanofluid concentration and target to plate distance were investigated. Two jet arrays were employed; inline and staggered. A 3-D numerical calculations using Ansys CFX with standard k-? turbulence model were presented. Results are obtained in terms of average Nusselt numbers, also the velocity, pressure, volume fraction and surface temperature contours were presented. The results show that, the best heat transfer enhancement was obtained at H/Djet=20 using staggered jet arrangement. From experimental results, about 48% and 57% increase in average Nusselt number were obtained for inline and staggered jet arrays respectively at 6 m/s velocity and 10% nanofluid volume fraction. The numerical results presented good agreement with experimental results at low Reynolds numbers. Correlation equations were created to calculate Nusselt number for both inline and staggered jets cooling systems.