MODIFIED HILPERT CORRELATION FOR TURBULENT CONVECTIVE HEAT TRANSFER FROM A NACA AIRFOIL

This article develops a modified Hilpert correlation to predict heat transfer by turbulent forced convection from a wind turbine NACA airfoil. The experimental method uses thermocouples embedded at different locations along the surface of the airfoil. Under steady-state conditions, heat conduction through the airfoil balances heat transfer by convection to the airstream. Experimental data was shown to fall consistently onto a single normalized correlation of Nu/Pr 1/3 at varying Prandtl numbers. Representative coefficients of the modified Hilpert correlation are reported. It is observed that the average Nusselt number for an airfoil is smaller than a flat plate and cylinder at the same Reynolds number, due to differences between turbulent boundary layer behavior after the transition point.