轴流压气机自循环抽吸-喷气非定常耦合扩稳机制研究

Self-recirculating injection can both enhance stability and improve efficiency of axial flow compressor. Recent years, it has been studied internationally, the different effect mechanism of front tip injection and after suction, which make its stability enhancement mechanism and geometric structure optimization is still one of the challenging scientific problems in turbomachinery. The front tip injection mainly act on the unsteady characteristics of blade tip region, but the impact mechanism of after suction will be changed with the change of suction location. So, the self-recirculating injection and unsteady characteristics of internal flow are chosen as a breakthrough point, this project intends to conduct the research from three aspects: (1) Numerical simulation and experimental investigations on coupling interaction of self-recirculating injection with unsteady flow flied characteristics; (2) The relationship between key parameters(the inherent excitation frequency which is formed by number matching of injectors and suction ports, suction location and geometric structure of injector and suction port) and stability,efficiency; (3) Design principles of self-recirculating injection in multistage axial flow compressor is proposed, and the experimental verification will be performed in low speed and transonic axial flow compressor. It aims to reveal the unsteady stability enhancement mechanism of self-recirculating injection, and base on the clarification of the relationship between unsteady characteristics of blade tip region, wake, rotor-stator interaction, blockage and stability, efficiency, the design basis of self-recirculation injection in multistage axial flow compressor is proposed, and the theoretical foundation will be provided for its practical application.

自循环抽吸-喷气能兼顾稳定裕度拓宽和效率改善的优点，在国际上受到了广泛的关注，但其扩稳机制仍是叶轮机械领域具有挑战性的科学问题之一。前端喷气主要作用于动叶顶部流场非定常特征，而后端抽吸的作用机制则会随着抽吸位置的变化而变化。因此，本项目将以自循环抽吸-喷气和内部流动的非定常特征为切入点，拟深入开展：（1）自循环抽吸-喷气与内部流场非定常耦合作用的数值模拟和实验验证；（2）流场非定常耦合作用的关键影响因素（喷嘴和抽吸口数目匹配、抽吸位置及几何结构）及其与稳定性和效率的关系；（3）提出自循环抽吸-喷气机构的设计准则，并在低速和跨音压气机上进行实验验证等三个方面的研究。旨在揭示自循环抽吸-喷气的非定常耦合扩稳机制，澄清叶顶端区非定常流场特征、叶片通道出口尾迹、动静干涉、堵塞与稳定性和效率关系的基础上，提出自循环抽吸-喷气机构的设计依据，为其走向实际应用提供理论基础。

本项目以自循环抽吸-喷气和内部流动的非定常特征为切入点，深入开展了以下几个方面的工作：（1）自循环抽吸-喷气扩稳能力验证；（2）自循环抽吸-喷气机构的结构优化；（3）紧凑式自循环抽吸-喷气机构设计及在单转子低速轴流压气机实验研究，在获得6.12%扩稳裕度且不影响效率的前提下获得了自循环抽吸-喷气的双重扩稳机制；（4）单级轴流压气机自循环抽吸-喷气能够获得13.67%的失速裕度改善，其抽吸量处于大喷气阶段，其扩稳机理涵盖了前端喷气对叶顶间隙泄漏流的影响；（5）三级轴流压气机上自循环抽吸-喷气能够获得13%的失速裕度改善，其抽吸量得到进一步增加，此时失速先兆发生了轴向迁移现象而使得失速裕度改善相对于单级条件下并未得到提升。上述工作旨在揭示自循环抽吸-喷气的非定常耦合扩稳机制，澄清叶顶端区非定常流场特征、叶片通道出口尾迹、动静干涉、堵塞与稳定性和效率关系的基础上，提出自循环抽吸-喷气机构的设计依据，为其走向实际应用提供理论基础。