Effects of Leading Edge Injection on the Film Cooling Characteristics of Multirow Cooling Holes on the Turbine Vane Suction Side

An experiment was carried out in the transonic wind tunnel to investigate the effect of leading edge injection on the cooling characteristics downstream of multirow film cooling holes on the turbine vane suction side. The film cooling effectiveness and heat transfer coefficient were obtained by the thermocouples. The inlet Reynolds number of the cascade ranged from 2.0×105 to 4.0×105 and the exit isentropic Mach number was 0.95, the turbulence intensity upstream of the cascade was less than 5%. Six rows of counter-inclined cylindrical holes were provided on the leading edge and the mass flow ratios ranged from 2.00% to 3.71%. Four rows of cylindrical holes were arranged on the suction side and the mass flow ratios ranged from 2.02% to 3.74%. The experimental results show that without the leading edge injection, the film cooling effectiveness on the suction side first increases then decreases with the mass flow ratio increasing, however, the effect of mass flow ratio on the film cooling effectiveness is not pronounced in the presence of leading edge injection. The increased mass flow ratio leads to enhanced heat transfer coefficient on the suction side for all cases. Compared with the cases without leading edge injection, the leading edge injection significantly improves the film cooling effectiveness and slightly reduces the heat transfer coefficient in the area near the hole rows on the suction side. In the rear half of suction side, the leading edge injection markedly enhances the heat transfer coefficient, whereas has little effect on the film cooling effectiveness. In summary, the leading edge injection improves the cooling performance in the vicinity of hole rows on the suction side, however, worsens the cooling performance in the rear half of the suction side. © 2021, Editorial Department of Journal of Propulsion Technology. All right reserved.