基于实测扭转度误差对叶片气动合格性探讨

Discussion on Aerodynamic Qualification of the Blade Based on Twist Angle Error Measured

在叶片实际加工过程中,不可避免会产生扭转度超差叶片,为探究其气动合格性,以跨声速叶片Rotor37为研究对象,首先将加工公差[-0.5°,+0.5°]添加至设计叶片,采用数值模拟的方法确定气动性能合格范围,分析性能变化规律;而后基于实测扭转度误差均值及标准差,创建加工合格以及超差叶片,总结其气动合格性。研究结果表明:受扭转度误差影响,叶片特性曲线整体偏移,因此在选择近失速及峰值效率工况参数衡量稳定裕度的前提下,“欠偏转”叶片稳定裕度减小,而“过偏转”叶片的增大;以加工公差为参考,叶片超差区域与未超差区域的通流面积和攻角变化趋势相反,即两区域对叶片性能的影响存在抵消作用,使得存在超差叶片气动合格的情况。

In the machining process,it is inevitable to produce out-of-tolerance blades.To study the aerodynamic qualification,the transonic blade Rotor37 was taken as the study object.Firstly,the machining tolerance[−0.5◦,+0.5◦]was added to the nominal blade,and the qualified range of aerodynamic performance was determined by the numerical simulation,whose change law was analyzed.Then,based on the measured twist angle error mean and standard deviation,machining qualified and out-of-tolerance blades were created,whose aerodynamic qualification was summa-rized.The results show that the blade characteristic curve shift as a whole owing to the influence of twist angle error.Therefore,when the stability margin is measured under the premise of select-ing the parameters under the near stall and peak efficiency conditions,the stability margin of the“under-deflection”blades decreases,while that of the“over-deflection”blades increases.Taking the machining tolerance as a reference,the flow area and angle of attack of the blade in the out-of-tolerance and non-out-of-tolerance area have opposite trend,i.e.,the influence of these two areas in the blade performance has an offsetting effect,so that there is a situation where the out-of-tolerance blade is aerodynamically qualified.