涡轮导叶压力面气膜孔排位置 对气膜冷却特性的影响

An experiment was conducted in the transonic wind tunnel to study the effect of film hole row position on the film cooling characteristic, four rows of single-row diffused film hole (represented by PS1~PS4) were arranged on the turbine vane pressure side. The film cooling effectiveness and heat transfer coefficient were achieved by the thermocouples downstream of the film cooling hole rows. The inlet Reynolds numbers of the cascade ranged from 3.0×10⁵ to 9.0×10⁵, the blowing ratios of PS1~PS4 ranged from 0.5 to 2.0 and the exit Mach number of the cascade was 0.8. The experimental results show that the film cooling effectiveness downstream of PS1 increases with the increase of blow ratio because of strong favorable pressure gradient. For PS2, the optimal blowing ratio in the region of less than 30D downstream of the hole row is BR=1.2 (D represents the diameter of film hole), whereas the highest film cooling effectiveness is obtained at BR=2.0 in the region of lager than 30D. At the same blowing ratio conditions, the film cooling effectiveness downstream of PS1 is lower than that of PS2 because the inclination angle of PS1 is larger, while the film cooling effectiveness downstream of PS1, PS2 and PS3 with the same inclination angle gradually decreases. The heat transfer coefficient ratio downstream of PS1~PS4 is greater than 1.0 due to the mixing of the coolant and mainstream, except for PS2 at BR=0.5. Higher blowing ratio produces higher heat transfer coefficient ratio for PS2 and PS3, while the effect of blowing ratio on heat transfer coefficient ratio is not pronounced for PS1 and PS4. Taking the film cooling effectiveness and heat transfer coefficient into consideration, the cooling performance of PS2 is the best with the same amount of coolant for PS1~PS4.