Numerical Study of Fluid Flow and Heat Transfer for Al₂O₃-Water Nanofluid Impinging Jet

In this study a circular confined and submerged jet impinging on a horizontal hot plate is numerically simulated. Water and 36nm Al₂O₃-water nanofluid with various particle volume fractions are used as a working fluid for cooling the hot plate. Both laminar and turbulent impinging jets in various nozzle to plate distances and Reynolds numbers are considered. For laminar cases Navier-Stokes and energy equations and for turbulent cases RANS and time averaged energy equations were solved numerically to obtain the flowfield and temperature distribution. The turbulence effect was considered with a two equations model. The properties of nanofluid such as thermal conductivity, viscosity and density are modified using the appropriate models. The present study reports the Nusselt number on the hot plate for investigated cases. Temperature difference between the inlet fluid and the hot plate are obtained for different mass flow rates and particle volume fractions and are compared with experimental data for turbulent jets. The results show that using Al₂O₃ nano-particles in laminar jets enhances the heat transfer but for the turbulent jets Al₂O₃-water nanofluid has a lower performance for heat removal compared with clear fluid.