前缘喷淋射流对导叶压力面冷却特性的影响

In order to evaluate the effect of showerhead injection of leading edge on the cooling characteristics of turbine vane pressure side with multirow film holes, an experiment was carried out in a high subsonic wind tunnel to obtain the film cooling effectiveness and heat transfer coefficient on the vane surface with/without showerhead injection of leading edge. The inlet Reynolds number of the cascade (based on the true chord length of the vane) varied from 2.0×10⁵ to 4.0×10⁵, the exit isentropic Mach number was 0.95. Six rows of cylinder holes were arranged on the leading edge and the range of mass flow ratio was 2.46%-4.57%, the pressure side was assigned with 6 rows of cylinder holes and the mass flow ratio varied from 2.00% to 3.71%. The experimental results showed that without showerhead injection of leading edge, the film cooling effectiveness on the front half of the pressure side was less affected by mass flow ratio, however, that on the rear half increased with the increase of mass flow ratio. The showerhead injection of leading edge raised the film cooling effectiveness of pressure side with multi-row holes by 20%~70%, and made the distribution of film cooling effectiveness more uniform along the flow direction. No matter whether the showerhead injection of leading edge existed, the heat transfer coefficient ratio on the pressure side increased with the mass flow ratio increasing. Viewed from streamwise, the showerhead injection of leading edge increased the heat transfer coefficient ratio in the region of leading and trailing edges on the pressure side, however, exerted a little effect in the middle region of pressure side.