Investigation on film cooling and aerodynamic performance of blade tip with tangential jet cooling scheme at transonic flow

An innovative blade tip cooling system is proposed in the current paper. The aerothermal characteristics of the blade tip with the tangential jet cooling scheme are investigated using the Pressure Sensitive Paint (PSP) technique under transonic flow conditions. The experiment is carried out at tip clearance gaps of 0.7% and 1.5% and four mass flow ratios. The cascade inlet Reynolds number and cascade exit Mach number are 370 000 and 1.05, respectively. The computational fluid dynamics method was used to analyze the flow characteristics of the blade tip. The bottom wall of the tip cavity downstream of the tangential jet cooling scheme is completely covered by the secondary flow. With the mass flow ratio (MFR) increasing, the film cooling effectiveness (η) of the whole blade tip surface is improved. The small tip clearance gap shrinks the low η region in the mid-chord cavity near the suction-side.