Experimental and Numerical Analysis of Convective Heat Transfer of Alumina Nanofluids Under Laminar Flow Regime

Heat transfer efficiency can be improved by increasing the thermal conductivity of the working fluids. Commonly used heat transfer fluids have relatively low thermal conductivities, when compared to the thermal conductivity of metals or metal oxides. High thermal conductivity of fluids can be increased by adding small amount of metals or metal oxide particles to that fluid. In this research, colloidal suspension alumina nanofluids were prepared by dispersing alumina nanoparticles in DI water as base fluid. Thermal conductivity of alumina nanofluids was then measured by means of hot wire technique using a LAMBDA system. The results reviled that the thermal conductivity enhancement was from 2.29% to 3.06% with 5 wt% alumina nanofluids at temperatures ranging from 15 to 40 °C. An enhancement of 37% average local convective heat transfer was achieved with 5 wt% alumina nanofluids at Re. 1100. The numerical data of convective heat transfer by CFD analysis using mixture model has also shown a good and satisfactory agreement with the experimental data. The present research is helpful to understand the thermal characteristics of low weight fraction alumina nanofluids under Laminar flow regime.