具有扩张形通道的高负荷压气机流动机理研究

The losses caused by tip clearance flow, secondary flow and boundary layer and tip clearance sensitivity are remarkable for the rear stage of multiple-stage axial compressors due to short length of blades and passage, which is well known as Size Effects. What’s more, the negative effects would increase significantly as the load of compressors grows. The “Diffuser Passage Compressor” (DP) could weaken the tip clearance flow and secondary flow by decreasing the pressure difference between suction surface and pressure surface, which could desensitize stall margin to tip clearance and improve the performance. This project is committed to fundamental research on the internal flow patterns and loss distribution of the highly loaded DP compressor based on plane cascades by experimental tests and numerical simulations. The influences of key parameters on the flow and performance for the DP compressor are investigated. In addition, the influences of inlet flow conditions on the DP compressor cascades are considered in the project. The aims of this project are to explore the flow mechanism behind the weakening of tip leakage flow and secondary flow, depict the main flow patterns, summarize the physical models and set up the design guidelines for highly loaded DP compressors. The ultimate goal is to provide fundamental theories and advanced technology for designing rear stage of multiple-stage axial compressors.

多级轴流压气机后面级叶片通道和高度小，受“尺寸效应”影响压气机叶顶间隙流动、二次流动和附面层造成的损失较大，叶顶间隙敏感性强，随着压气机级负荷的不断提高，这一特征将会更加明显，压气机性能将会严重受到限制。具有扩张形通道特征的压气机能够通过降低叶片压力面与吸力面之间的压差，有效弱化叶顶间隙流动和端区二次流动，降低压气机的间隙敏感性，提高性能和稳定工作范围。本项目以具有扩张形通道的高负荷压气机叶栅为研究对象，借助高精度测量和数值模拟手段，重点开展具有扩张形子午流道的高负荷轴流压气机内部流动特性和关键参数影响规律研究，探索利用扩张形通道特征有效降低压气机间隙泄漏流动和二次流动的物理机制，提炼扩张形通道高负荷压气机内部典型的流动特征，探讨不同来流条件对扩张形通道压气机叶栅内部流动和气动性能影响，总结物理模型，建立具有扩张形通道的高负荷压气机设计方法，为高负荷压气机后面级的设计提供理论支撑。

针对多级高负荷轴流压气机后面级受“尺寸效应”影响，叶顶间隙敏感性强的问题，提出了采用具有扩张形子午流道特征的轴流压气机结构以调控叶顶间隙流动的方案。在基金的资助下，本项目采用数值模拟手段开展了叶型最大弯度位置、叶片端弯以及叶栅稠度等关键参数对扩张形通道压气机内部流动和性能的影响规律研究。在优化关键参数的基础上设计了具有扩张形通道特征的平面叶栅（扩散因子为0.64）。在试验台上完成了对叶顶间隙流动、二次流动以及近机匣、轮毂壁面处附面层流动的详细测量，揭示了扩张形通道高负荷压气机内部流动的物理机制。如期完成了所有研究内容。同时，开展了扩张形通道压气机叶顶间隙敏感性研究，通过对比分析，揭示了扩张形通道压气机间隙敏感性降低的物理机制。在此基础上，完成了扩张形通道高负荷压气机设计方法的总结，并在高速压气机试验台上进行了试验验证。与传统压气机相比，以扩张形通道压气机为后面级的两级高负荷压气机在设计转速峰值效率提高0.7%的情况下，综合裕度提高了4.8%。.结合项目研究，总计发表相关论文15篇，其中SCI索引论文5篇，EI索引5篇，国际会议论文4篇；授权发明专利2项；培养硕士研究生1名；参加国际会议2次；项目负责人参加基金委组织的项目中期评估并做口头报告，获得省部级奖励2项，入选为2020年中国科学院青年创新促进会成员。