叶顶间隙偏差对叶片气动性能影响的不确定性研究

Uncertainty Research of Effects of Blade Tip Clearance Deviation on Blade Aerodynamic Performance

关键词:  叶顶间隙  加工偏差  非嵌入式混沌多项式  气动性能  不确定性量化

Key words:  Blade tip clearance  Manufacturing error  Non-intrusive polynomial chaos  Aerodynamic performance  Uncertainty quantification

摘要:

在压气机叶片加工过程中，实际加工得到的叶片外形与设计叶型不可避免会存在一些偏差。为研究叶片叶顶间隙尺寸波动对性能的影响，以Rotor 37为研究对象，采用三维定常数值模拟方法，基于非嵌入式混沌多项式中二维正态分布变量产生方法，分别对叶片前缘叶顶间隙和尾缘叶顶间隙进行尺寸波动干扰，研究了叶顶间隙不确定性对气动性能和流场的不确定性影响，评估了公差带内叶顶间隙偏差与气动性能变化的相关性，并探究了叶顶间隙变化对叶片稳定裕度的影响机理。研究发现，叶顶间隙偏差对等背压条件下叶片质量流量、等熵效率和总压比的平均水平几乎不会造成影响；叶顶间隙偏差所造成的气动性能分布标准差随工况点向不稳定边界的逼近而逐渐增大。同时，叶顶间隙不确定性会导致样本稳定裕度均值有所降低，不确定性分析中稳定裕度均值相对原型叶片下降了2.42%。流场结构方面，叶顶间隙偏差主要影响80%叶高以上部分流场；叶顶间隙偏差对叶顶区域泄漏流产生的影响，导致了叶片稳定裕度的变化。

Abstract:

The deviation between the actual processed blade and the designed blade shape inevitably occurs in the process of compressor blade manufacturing. Rotor 37 was used as the research object， and the three-dimensional constant value simulation method was adopted in order to study the effects of blade tip clearance size fluctuations on blade performance. The size fluctuation interference of the leading edge tip clearance and the trailing edge tip clearance of the blade are respectively performed based on the two-dimensional normal distribution variable generation method in the non-intrusive polynomial chaos. The effects of the uncertainty of the tip clearance on the aerodynamic performance and the uncertainty of the flow field were studied， the correlation between the tip clearance deviation within the tolerance zone and the change of aerodynamic performance was evaluated， and the mechanism of the effects of the tip clearance change on the blade stability margin was explored. The study found that the tip clearance deviation has almost no effect on the average level of blade mass flow， isentropic efficiency and total pressure ratio under equal back pressure conditions. The influence of tip clearance deviation on the standard deviation of aerodynamic performance distribution gradually increases with the approach of the operating point to the unstable boundary. At the same time， the blade tip clearance deviation will cause the sample stability margin to be reduced， and the average stability margin in the uncertainty analysis is 2.42% lower than that of the prototype blade. The tip clearance deviation mainly affects the flow field above 80% of the blade height， and the effects of the tip clearance deviation on the tip leakage flow result in the change of the blade stability margin.