Experimental investigation of the full coverage film cooling effectiveness of a turbine blade with shaped holes

Abstract

The film cooling effectiveness of two turbine blades at different turbulence intensities (0.62% and 16.00%) and mass flux ratios (2.91%, 5.82%, 8.73% and 11.63%) is studied by using the Pressure-Sensitive Paint (PSP) measurement technique. There are a baseline and an improved turbine blade in current work, and their film cooling hole position distribution is the same. But the hole shape on suction surface and pressure surface is changed from cylindrical hole (baseline) to laid-back fan-shaped hole (improved blade). Both blades have 5 rows of cylindrical holes at the leading edge and 4 rows of cooling-holes on the suction surface and the pressure surface. The experimental results show that the film cooling effectiveness of the improved blade is much better than the baseline. The increase in turbulence intensity will reduce the cooling effectiveness on the surface of turbine blade, but the effect of turbulence intensity becomes weaker with an increase in the mass flux ratio. Compared with the multiple rows of cylindrical holes, the cooling effectiveness of shaped holes is more influenced by the turbulence intensity at low mass flux ratio.