尾迹扫掠下高负荷低压涡轮端区复杂流动机理及其调控研究

With the goal of meeting the national requirements on the high-performance civil aero-engine, at the level of the interdisciplinary of the engineering theromphysics and fluid mechanics, the flow mechanism and control strategy in the high-lift low pressure turbine under periodic upstream wakes was conducted. Particular emphasis is placed on the influence of the periodic wake on the laminar-turbulent transition process on the blade suction surface and on the unsteady behaviors of the endwall secondary flow. Measurement was made in the large-scale low-speed turbine cascade wind tunnel by means of the multi-hole pressure probe, oil-flow visualization, hot-wires and fast-response pressure probes. Experimental data were supplemented with high-precision numerical predictions from a commercially available Computational Fluid Dynamics code. In addition to that, innovation flow control strategies by coupling the upstream wakes and endwall contouring was proposed to reveal the coupling mechanism between the periodic passing-wake and the tailed endwall. This resulted in the suppression of the endwall secondary flow, reducing the losses and improving the turbine aerodynamic performance, which provides the basic support for the detailed design of the highly-loaded low pressure turbine for the high performance aero-engine.

本项目面向高性能航空发动机研制的国家重大需求，在工程热物理与流体力学学科的交叉层面，针对叶轮机械内部复杂流动问题，在高负荷低压涡轮端区复杂流动机理与调控方面开展深入研究。拟以大尺寸低速叶栅实验台为研究载体，借助由多孔探针、油流显示、快速响应压力探针、热线和表面热膜构建的测试系统以及高精度数值模拟方法，进一步认知尾迹扫掠下高负荷低压涡轮叶片附面层变化及其端区复杂流动时空演化过程，揭示附面层与端区二次流相互作用机理及其损失输运机制，阐明尾迹扫掠下端区二次流非定常流动特征；在此基础之上，探索尾迹扫掠和非轴对称端壁耦合的端区二次流调控方法。深入分析尾迹扫掠下非轴对称端壁对端区二次流及涡系影响机制，变更尾迹参数，优化端壁几何结构，实现非轴对称端壁与上游尾迹的气动耦合，最大限度抑制高负荷低压涡轮端区二次流发展，降低损失，提高涡轮气动性能，为我国高性能航空发动机高负荷低压涡轮精细化设计提供基础性支撑。

本项目面向高性能航空发动机研制的国家重大需求，在工程热物理与流体力学学科的交叉层面，针对叶轮机械内部复杂流动问题，在高负荷低压涡轮端区复杂流动机理与调控方面开展深入研究。依托具有尾迹扫掠模拟功能的低速平面叶栅实验台，借助由高频响动态压力探针、热线探针、多孔探针等先进测量手段，结合高精度数值模拟方法。进一步认知尾迹扫掠下高负荷低压涡轮叶片附面层变化及其端区复杂流动时空演化过程，掌握了上游尾迹对端区二次流、叶片附面层以及相关损失的影响规律，详细探讨了来流雷诺数、端壁边界层厚度对端区二次流的影响机理，并尝试利用上游尾迹扫掠抑制端区二次流的发展，建立了高负荷低压涡轮端区非定常涡系结构物理模型，并将机理性研究成果应用到高负荷低压涡轮流动控制当中，探索上游尾迹与非轴对称端壁对端区二次流的耦合调控机制，从而提高低压涡轮部件的气动性能，为我国高性能航空发动机高负荷低压涡轮精细化设计提供基础性支撑。