跨声速流中圆锥孔在涡轮动叶叶顶上的气膜冷却特性实验研究

Experimental Investigation on Film Cooling Characteristics of Conical Holes on a Turbine Blade Tip in Transonic Flow

关键词:  跨声速流  气膜冷却  涡轮叶顶  密度比  质量流量比

Key words:  Transonic flow  Film cooling  Turbine blade tip  Density ratio  Mass flow ratio

摘要:

采用实验方法研究了跨声速流中圆锥孔在涡轮动叶叶顶上的气膜冷却特性。通过压敏漆测试技术系统全面分析了质量流量比和密度比对带圆锥孔凹槽叶顶上气膜冷却效率分布的影响规律。基于轴向弦长的叶栅通道入口雷诺数为3.68×10⁵，叶栅通道出口马赫数为1.05。质量流量比为0.1%+0.05%，0.14%+0.07%和0.21%+0.105%。密度比为1，1.5和2。结果表明：质量流量比越小，叶顶上圆锥孔的导流作用越强，冷气在叶顶上的覆盖面积增加。质量流量比过大时冷气集中成束从圆锥孔射出，冷气在叶顶上扩散性较差。随着密度比增加，叶顶上的气膜冷却效果逐渐改善，特别是大质量流量比条件下。

Abstract:

The film cooling characteristics of a turbine blade tip with conical holes are experimentally studied in transonic flow. The pressure sensitive paint technique is used to analyze effects of mass flow ratios and density ratios on the film cooling effectiveness distribution of the squealer tip with conical holes. The cascade inlet Reynolds number is 3.68×10⁵ based on the chord length， and the cascade exit Mach number is 1.05. The experiment is carried out at three mass flow ratios of 0.1%+0.05%， 0.14%+0.07%， and 0.21%+0.105%， and three density ratios of 1， 1.5， and 2. The results show that the lower the mass flow ratio， the stronger the guidance action of conical holes， increasing the coolant coverage on the blade tip. However， the coolant is concentrated in bunches and ejected from the conical hole at the high mass flow ratio， which has a negative effect on the film coverage on the blade tip. With the density ratio increasing， the film cooling performance of the blade tip is improved， particularly at the high mass flow ratio.