Investigations of film-cooling and heat transfer characteristics on blade endwall with cylindrical holes and shaped holes with constant export area

Film cooling and heat transfer performances on transonic turbine rotor passage of cylindrical holes and fanshaped hole with constant export area are studied. Effect of blowing ratio, compound angle and film-hole axial position are studied. Results show that end-wall cooling and heat transfer performances determined by the interaction between coolant jet and vortex. The fan-shaped holes are very sensitive to variety in compound angle and blowing ratio. For row 1, the eta of fan-shaped holes (baseline) is reduced by 34.5 % at maximum compared to the fan-shaped holes (compound angle). At low M, the fan-shaped holes (compound angle) achieved better adiabatic film-cooling performance compared to the cylindrical holes. When taking into account both film cooling and heat transfer, due to the suppression of cross flow by the jet at high M, the heat transfer of the endwall is reduced, resulting in better cooling performance for the cylindrical holes (baseline) for the row 1 and row 2 than fan-shaped holes (compound angle). The NHFR of the row 1 and row 2 is increased by 16.5 % and 10.2 %, respectively. Therefore, in the appropriate area of the rotor passage, consider using cylindrical holes with larger diameters instead of fan-shaped holes.