Improvement of Turbine Vane Film Cooling Performance by Double Flow-Control Devices

This study deals with the studies of the effect of flow control double device (DFCD) on a turbine vane film cooling. Aiming for improving film effectiveness, two semi-elliptical DFCDs per a pitch were attached obliquely upstream of the cooling hole. Since the DFCDs were applied to flat plate film cooling in the previous study, the applicability to the turbine vane was investigated in this study. In order to observe a flow field in detail, RANS CFD was conducted first. The DFCDs were installed upstream of each cooling hole of the pressure and suction sides of the vane to investigate the effect of the device position. In this paper, the effects of blowing ratio and cooling hole pitch were also investigated. The results obtained by CFD showed that the vortex generated from DFCD suppressed lift off of the secondary air. As a result, the film effectiveness became significantly higher than that without DFCD condition at high blowing ratio. Moreover, the improvement in the film effectiveness by DFCD was observed by both of the pressure and suction sides of the turbine vane. Based on the findings through RANS simulation, adiabatic effectiveness and total pressure loss coefficient measurement were performed in a linear cascade test facility. The experiment confirmed that the film effectiveness improved when DFCDs existed.