射流角度对姊妹孔气膜冷却效果影响实验研究

为了分析主孔与侧孔射流角度对逆向射流姊妹孔平板模型气膜冷却效率影响,采用压力敏感漆(PSP)技术对单孔顺流与5种姊妹孔在四种吹风比(BR)下的绝热气膜冷却效率进行研究。结果表明姊妹孔在所有吹风比下气膜冷却效果均优于单个圆孔正向射流。低吹风比(BR=0.5)时,姊妹孔气膜冷却效果相近,但顺流姊妹孔气膜冷却效果最佳;中吹风比(BR=1)、高吹风比(BR=1.5,2)下,侧孔顺流的逆向射流姊妹孔气膜冷却效果最佳,相比于单孔射流的面平均气膜冷却效率可提高366%,677%,727%。逆向射流可令姊妹孔获得更高的气膜覆盖率,具有复合角度的侧孔射流可在低、中吹风比下增加逆流姊妹孔的展向气膜覆盖率,但在高吹风比下,对姊妹孔下游流向气膜冷却效果产生较差影响。

Experimental Study on Effects of Injection Angles on Film Cooling Performance of Sister Holes

To analyze the effects of the injection angles of the primary hole or the side hole on the sister hole film cooling performance of a flat plate model, pressure sensitive paint (PSP) technology was used to study the film cooling performance of a single hole and five sister holes. The results show that the sister holes had a better film cooling performance than the single hole at four blowing ratios (BR). The sister hole had a similar average spanwise film cooling efficiency at a low blowing ratio (BR=0.5). The area mean film cooling efficiency of the sister holes with the forward jet of the side hole was the highest, which were 3.66, 6.77, 7.27 times higher than the area mean film cooling efficiency of the single hole at medium blowing ratio (BR=1) and high blowing ratios (BR=1.5, 2). The film coverage of the sister holes could be increased by the backward jet, the spanwise film cooling performance of the backward sister holes could be improved by the spanwise angle of the side hole when the BR was 0.5 or 1. But the streamwise film cooling effectiveness of the sister hole decreased with the compound angle of the side hole at high blowing ratios.