EFFECT OF PARTICLE SHAPE ON HEAT TRANSFER AND ENTROPY GENERATION PERFORMANCE OF Al2O3/WATER NANOFLUID JET FLOW IMPINGING ON A CONVEX SURFACE

Abstract

This study consists of numerical analyses for impinging jet flow over a convex surface by using Al2O3-water nanofluids having different volume fractions and particle shapes. Heat transfer and pressure drop performance was investigated by using 1.0%, 2.0%, 3.0%, and 4.0% volume fractions of alumina nanofluids with the following shapes of particles: blades, bricks, cylinders, and platelets. The flow structure and thermal behavior were determined and the local Nusselt number and entropy generation variations were obtained under laminar flow conditions according to the Reynolds number and jet-to-target distance. Flow was considered fully developed both hydrodynamically and thermally. Maximum Nusselt number enhancement at the stagnation point was achieved with 4.0% volume fraction Al2O3-water nanofluid having platelet-shaped particles as 47.63% when comparing to pure water. Based on the entropy generation calculations, the minimum Bejan number was calculated with nanofluid having platelet-shaped 4.0% alumina particles as 0.022 at a Reynolds number of 500. It was revealed that particle shape of nanofluids strongly affects the heat transfer and pressure drop performance.