SHOWERHEAD FILM COOLING MECHANISM AND SUPERPOSITION CHARACTERISTICS OF TURBINE BLADE LEADING-EDGE

Based on the turbine blade model, the film cooling effectiveness data of single rows of holes at different positions were obtained through numerical simulation, and the superposition characteristics of multiple rows of holes under different average blowing ratios were studied. The applicability of the Sellers superposition formula to the blade leading-edge is discussed. The showerhead film cooling effectiveness distribution of the leading-edge was studied through pressure sensitive paint (PSP) experimental measurement, and the numerical simulation method was verified. The results show that the Sellers superposition formula accurately predicts the average film cooling effectiveness on the leading-edge surface under small and medium blowing ratios. Under large blowing ratios, the prediction accuracy of the superposition formula is significantly reduced. The strong interference of the mainstream and secondary jet flow and the formation of a vortex tube between multiple rows of holes are the main reasons for the failure of the two-dimensional superposition formula and the formation of a sheet-shaped high-film cooling effectiveness area under a large blowing ratio. Changes in the row-of-holes layout have an impact on the film cooling effectiveness distribution but have little effect on the prediction of the area average by the Sellers superposition formula. The experimental measurement data of film cooling effectiveness at large blowing ratios combined with the Sellers superposition formula constitute a reference for designing leading-edge showerhead film cooling structures, which have important application value for engineering design.