Film cooling of showerhead holes from the twisted leading edge of a gas turbine blade: Complex mainstream characteristics and reasonable angle arrangement

The flow trends of gas mainstream and coolant ejection in the blade fluid domain are closely related to the non-uniform profile characteristics of gases before the turbine stage. The validity of the non-uniform pressure and temperature profile for the mainstream was determined under the typical working conditions of a torsion blade by comparing the differences between the experimental and numerical simulation results of the leading-edge Mach numbers for various mainstream cases. Then, the film cooling effectiveness of the showerhead holes at the leading edge of the gas turbine twisted blade under the non-uniform mainstream was analyzed. The influence mechanism and rule of the radial angle and streamwise torsion angle on the cooling effectiveness of the leading-edge showerhead were analyzed using the jet characteristics of single film and the spanwise average film cooling effectiveness, respectively. Finally, analyzing the influence of different coupling angles on the cooling effectiveness of the leading-edge region provided the optimal angle arrangement scheme. The results show that the reasonable coupling angle arrangement of showerhead holes can enhance the cooling effectiveness in the leading-edge region. Thus, the coupling angle arrangement should be considered in the engineering design for the leading edge of gas turbine blades.