下游势流耦合上游尾迹对低压涡轮附面层影响的研究

The low pressure turbine (LPT) with the highly loaded and compact design has such advantages as compact structure and high power weight ratio. However, the impact produced by the downstream potential flow is increased along with the reduced axial spacing between the blades rows, especially under the coupled effect with the periodical upstream wakes, which will further result in a more complicated unsteady boundary layer flow on the blade suction side. In the present application, a highly loaded LPT airfoil is taken as the research object, and a linear cascade which can simulate the upstream wakes and the downstream potential flow is used as the research carrier, thus studying the impact to the boundary layer on the mid-row blade suction side produced by the downstream potential flow and the downstream potential flow coupled with the upstream wakes. The influence of the downstream potential flow and the upstream wakes to the boundary layer on blade suction side are analyzed considering the effects of operating parameters. Based on the downstream potential flow and the upstream wakes, the flow of the boundary layer is reconstructed, and a more optimum coupled way is further explored to reduce the profile loss, thus providing basic theoretical support for the design of the highly loaded and compact LPT.

采用紧凑型高负荷设计的低压涡轮（LPT）具有结构紧凑、功重比高等优点，但叶片排间距的减小会导致下游势流的影响增强，特别是在其与周期性上游尾迹耦合后，将使叶片吸力面附面层的非定常流动更加复杂。本项目拟以高负荷LPT叶型为研究对象，以能模拟上游尾迹与下游势流的平面叶栅实验台为研究载体，依托动态流场测试设备，掌握下游势流及其与上游尾迹耦合后对中间叶片吸力面附面层发展的作用机理。揭示下游势流匹配上游尾迹对LPT叶片附面层非定常流动的参数化影响规律，并基于下游势流与上游尾迹重组附面层内部流动，探索两者的最佳耦合方式来最大限度地降低叶型损失，为紧凑型高负荷低压涡轮的设计提供基础性的理论支撑。

在现代大涵道比涡扇发动机中，低压涡轮(LPT)由于尺寸大，级数多，其重量通常占发动机总重的20%-30%。除使用高负荷叶型设计外，还可采用紧凑型设计来缩短叶片排间距，达到为LPT减重的目的。本项目以高负荷LPT叶型为研究对象，以能模拟上游尾迹与下游势流的平面叶栅实验台为研究载体，依托动态流场测试设备，掌握下游势流及其与上游尾迹耦合后对中间叶片吸力面附面层发展的作用机理。揭示下游势流匹配上游尾迹对LPT叶片附面层非定常流动的参数化影响规律，并基于下游势流与上游尾迹重组附面层内部流动，探索两者的最佳耦合方式来最大限度地降低叶型损失，为紧凑型高负荷低压涡轮的设计提供基础性的理论支撑。利用新型的上下游叶片布局，对于1.5级（转-静-转结构），在高来流湍流度下（FSTI=4.0%）叶型损失可降低0.5%，轴向长度可缩短20%Cx，达到了项目考核指标要求。在该项目资助下，累计发表论文3篇，其中已发表SCI论文1篇，EI论文2篇，授权发明专利1项，专利转化费用2万元，培养研究生1名。