Roughness impact on turbine vane suction side film cooling effectiveness

This study investigates the effect that surface roughness has on the adiabatic effectiveness performance of the first row of suction side cooling holes on a turbine inlet guide vane. The effects of roughness placement (roughness upstream, downstream, or combined up and downstream of the row of film cooling holes) are investigated. Additionally, for each roughness placement, the effect of mainstream turbulence level and showerhead coolant will be quantified. To gain insight into the state of the boundary layer just upstream of the row of film cooling holes, a hot-wire anemometer will be used to measure the velocity and turbulence profiles that exist under various conditions. It was found that roughness degrades the adiabatic effectiveness performance of low blowing ratios and enhances the adiabatic effectiveness performance of high blowing ratios. Roughness also shifts the optimum blowing ratio, toward higher coolant flow rates. Roughness thickens the boundary layer and increases its turbulence intensityMechanical Engineerin