高负荷跨音速涡轮缩扩型流道动叶中激波与冷却气体作用机理研究

This application will focus on the interaction between shock wave and film-cooling air happening in a highly loaded transonic turbine rotor with convergent-divergent blade. The interaction between shock wave and coolant in the highly loaded transonic turbine certainly will cause the main flow characteristic changed, such as the position of shock wave, the unsteady characteristic of mixture between mainstream and coolant, the migration of boundary layer separation on blade surface. The purpose of the application is to clarify and explain the relationship between shock wave and coolant. Based on the research situation and the development trend of summarizing and analyzing the interaction between shock wave and film-cooling air, the investigations are conducted as follows:.(1) The research on the interaction regular pattern and evaluation criterion between shock wave and coolant in a highly loaded transonic turbine rotor with convergent-divergent blade..(2) The investigation on the unsteady flow characteristic caused by coolant injection in consideration of shock wave..(3) The mixture loss model involving the influence of shock wave..The strongpoint of this project is that it will show the interaction coupling mechanism between shock wave and film-cooling air and establish a mixture loss model of the highly loaded transonic turbine. On resolving above-mentioned problems, hopefully the interaction mechanism between shock wave and coolant can be clarified via principle of internal flow, which can offer the theoretical supports for aerodynamic optimization design and performance estimation of the highly loaded and ultra-highly loaded turbine.

本项申请将围绕高负荷跨音速涡轮缩扩型流道动叶中激波与冷却气体的相互作用展开。高负荷跨音速涡轮中两者相互作用的存在势必会导致其内部流动的主要特征（激波位置、主流与冷却流掺混的非定常特征、叶片表面附面层分离迁移等）发生变化，澄清和诠释两者的关联是提出本项申请的目的。在总结分析涡轮中激波和冷却气体相互影响问题的研究现状和发展趋势的基础上，开展的主要研究工作包括：（1）高负荷涡轮缩扩型流道动叶中激波和冷却气体相互作用规律及评价机制研究；（2）激波影响下冷气射流引起的非定常流动特征研究；（3）考虑激波影响的掺混损失模型研究。申请项目的特色在于揭示激波和冷却气体相互作用的耦合机制，建立高负荷跨音速涡轮中的掺混损失模型。通过解决上述问题，希望从内部流动机理上澄清激波与冷却气体的作用机制，为高负荷/超高负荷气冷涡轮的气动优化设计和性能预估提供理论支撑。

本项目围绕高负荷跨音速涡轮缩扩型流道动叶中激波与冷却气体的相互作用展开，主要完成了冷气喷射对缩放型流道涡轮叶栅性能影响的数值研究、冷气喷射对缩放型流道涡轮叶栅性能影响的实验研究、尾缘冷却的数值研究工作。以高负荷跨音速涡轮缩扩型流道动叶为研究对象，采用数值模拟方法针对六个不同轴向位置处喷射冷气对缩放型流道涡轮叶栅性能的影响进行了详细的研究，着重分析了冷气喷射位置、冷气与主流质量流量比等影响因素，结果表明，在吸力面内伸波反射点附近喷射冷气可以减弱内伸波强度，这主要是由于射流冷气滞止了冷气孔前的气流，造成较大的逆压梯度，孔前压力升高，使得内伸波前后压差减小。利用跨声速平面叶栅实验台针对非设计工况时缩放型流道涡轮叶栅流动特性和冷气喷射对其性能的影响进行了实验研究，并对缩放型流道涡轮叶栅中波系结构随膨胀比的变化做了纹影实验，对不同攻角、不同膨胀比及不同冷气流量时的叶栅进出口参数、叶表静压、端壁静压进行了测量，实验结果与数值模拟结果符合较好，并且在内伸波作用位置处，实验与数值模拟均捕捉到了内伸波引起的流场变化。通过本项目研究，从内部流动机理上基本澄清了激波与冷却气体的作用机制，为高负荷/超高负荷气冷涡轮的气动优化设计和性能预估提供了理论支撑。