为量化评估工程应用的气冷低压涡轮带冠转子叶片的叶尖间距大小对涡轮气动性能的影响，综合现有涡轮部件试验能力，以单级轴流低压涡轮性能试验件为基础，通过控制圆度的机加方式磨削转子外环内壁以实现叶尖间距的变化，采用控制冷气流量比的方法，开展5次不同叶尖间距大小的涡轮级性能试验，得到多工况下涡轮效率、换算流量和换算功率等特性参数。采用加载冷气及考虑转子叶冠结构的数值模型进行三维仿真计算，并与试验结果对比分析。研究表明：叶尖间距由0.6 mm增加至3.2 mm，低压涡轮流通能力增大1%，叶冠泄漏量增多34%，但做功能力下降23%。涡轮效率变化与叶尖间距大小近似呈线性关系，叶尖间距每增加1 mm，效率约降低0.7%，同时，叶尖间距的增加导致了叶冠腔的旋涡结构、气流掺混及主流入侵强度逐渐增大，引起动叶总压损失的增大，叶尖间距增加至3.2 mm导致叶间位置总压损失由0.88增至2.3。

To quantitatively evaluate the impact of blade tip clearance on the aerodynamic performance of aircooled lowpressure turbine shrouded rotor blades in engineering applications, considering the existing turbine component testing capabilities, a single stage axial flow lowpressure turbine performance test piece was used as the basis. By grinding the inner wall of the outer ring of the rotor through a controlled roundness machining method to achieve changes in blade tip clearance, five turbine performance tests with different blade tip clearance sizes were conducted using the method of controlling the cold air flow ratio. Characteristic parameters such as turbine efficiency, corrected flow and corrected power were obtained under multiple operating conditions. A threedimensional numerical calculation was conducted using a numerical model loaded with cold air and considering the rotor blade shroud structure, and the results were compared and analyzed with experimental results. Research shows that as the blade tip clearance increases from 0.6 mm to 3.2 mm, the lowpressure turbine flow capacity increases by 1%, the leakage of blade shroud increases by 3.4%, but the power output decreases by 2.3%. The change in efficiency is approximately linear with the size of the blade tip clearance, for every 1 mm increasing in blade tip clearance, the turbine efficiency decreases by 0.7%.At the same time, the increase in blade tip clearance leads to a gradual increase in the vortex structure, airflow mixing and mainstream invasion intensity of the blade shroud cavity, resulting in an increase in the total pressure loss of rotor blades. During the process of blade tip clearance increasing to 3.2 mm, the average total pressure loss at the blade tip position increases from 0.88 to 2.3.

V231.3

国家科技重大专项资助项目（J2019II0010031）