Effect of free-stream turbulence on turbine blade heat transfer and pressure coefficients in low Reynolds number flows

Abstract

The effect of free-stream turbulence on heat transfer and pressure coefficients of a turbine blade was investigated in low Reynolds number flows. Cascade inlet Reynolds number based on blade chord length was varied from 15,700 to 105,000 and turbulence intensity was varied from 0.68% to 15.31%. This study documents the effect of increasing Reynolds number and free-stream turbulence in suppressing separation, promoting boundary layer transition, and enhancing heat transfer on blade surfaces. This may be the first documentation of both the pressure coefficient and Nusselt number distributions on the surfaces of a turbine blade at such low Reynolds numbers. The experimental data are useful for calibrating computational fluid dynamics (CFD) and direct numerical simulation (DNS) codes for predicting turbine blade heat transfer and flow behaviors.