Control of separation losses on turbine blade with low Reynolds number

The Reynolds number of turbine, especially the low-pressure turbine, of turbofan engine is very low during the long loiters at high altitudes for the unmanned aerial vehicles (UAVs), and this low Reynolds number results in the notable drop of efficiency of turbine. The objective of the present work was to explore the control method of flow separation on the turbine blades with the low Reynolds number. In the current investigation, the available and contemplated flow-control methods particularly suited for low Reynolds number airfoils were first surveyed. Dimpled blade, which is one of the surface treatment based on the golf-ball dimple structure, was investigated in present study. The horseshoe vortices created behind the dimples are the main cause for the delay and elimination of flow separation. Numerical simulation results for the dimpled airfoil of the mid-span section of the low-pressure turbine rotor blade of a turbofan engine are inspiring.