气冷涡轮叶尖泄漏流动的高低速模化设计及实验研究

The tip leakage flow and air coolant of the high pressure turbine blade have significantly influence on the aerodynamic performance and tip heat load distribution of the high pressure turbine, the interaction between tip leakage flow and air coolant increases the complexity of the flow and heat transfer problems in this region, this problem has brought great challenge for the design of the high efficiency air-cooled turbine. The project aims to the research of the dynamic process of tip leakage flow and air coolant interaction considering the relative motion of the blade and casing, it also aims to reveal the similarities and differences of the tip leakage flow and the air coolant interaction mechanism between the high and low speed conditions which could influence the tip flow field structure and cooling efficiency; In order to determine the similarity criteria, this project will research the high-low speed modeling design for tip flow field of turbine rotor blade, this research could provide technical support for the future study of the low speed dynamic test; the research of the turbine tip could be taken as a breakthrough to develop and improve the aerodynamic and heat transfer concurrent design methods of air-cooled turbine which could guide the air coolant to change the flow field, this concurrent design methods could reduce aerodynamic losses and increase the cooling efficiency effectively. This project could provide certain technical reserves and support for the wide-body aircraft engines through the study of these basic science and technology issues.

高压涡轮动叶叶尖泄漏流及冷气对涡轮气动性能和叶尖热负荷的分布存在显著的影响，两者的相互作用加剧了该区域流动与传热问题的复杂性，为气冷涡轮设计工作带来了巨大挑战。本项目旨在考虑叶片与机匣相对运动前提下，详细研究叶尖泄漏流与冷气相互作用的动态过程，探索高低速工况下叶尖泄漏流与冷气相互作用机理的异同点及其对叶尖流场结构和冷却效率的影响规律；考虑叶尖流动和传热相似性，对涡轮叶尖进行高低速模化设计，确定相似准则，为后续低速动态实验研究提供技术支持；以涡轮叶尖为突破口，开发和完善气冷涡轮气动、传热并行设计方法，合理组织冷气流动激励流场，达到降低掺混损失的同时提升冷却效率的最终目的。通过对上述基础科学问题和技术的研究，本项目将为新一代宽体客机发动机的研制提供一定的技术储备和支持。

高压涡轮叶尖冷却技术是航空发动机的一大设计难点，直接关系到整机性能，可靠性及寿命。本项目成功设计调试了一套新型的高速旋转试验台，获得了典型高压涡轮动叶的叶尖温度场，为研究相对运动对叶尖热负荷影响奠定了基础。本项目选取典型高压涡轮凹槽叶尖结构为研究对象，设计了多种不同形式叶尖冷却结构.以跨音速风洞试验以及CFD计算分析为研究手段，在接近发动机实际操作工况下，获得了高质量高分辨率的叶尖表面传热分布云图。项目执行过程中，对传热实验中涉及的温比模化过程也做了深入探讨，对高低速模化设计中叶尖的形式进行了探索。本项目的开展，使得针对叶尖的试验研究手段更为准确，对于叶尖冷气与泄漏流的掺混及流动换热机理的理解更为深入，有助于推动国产发动机叶尖冷却技术的改进与革新。