波纹度偏差对高负荷压气机叶型的影响

Effect of Waviness Deviation on the Blade Profile ofthe High-Load Compressor

基于对压气机叶片局部加工质量的分析,针对描述波纹度的关键参数,提出了描述波纹度加工偏差的正弦函数数学模型。该模型针对叶片加工型面存在的“微小波纹”现象,用幅值、频率和初始相位高效直观地体现了波纹度的波纹高度、波纹宽度和波纹初始相位参数。以某发动机高负荷叶型为对象,采用数值模拟手段研究了波纹度偏差关键几何参数对压气机高亚声速叶型气动性能的影响规律及机理。结果显示:在波纹宽度与起始相位相同的前提下,攻角范围会随着波纹高度的增加而减小,叶背局部波纹高度增加会导致流动损失增加;加工质量差的波纹高度大且波纹宽度小的叶型性能退化最严重,Ma=0.8时损失系数相较于设计叶型至少升高24.2%。根据文中结果对现有加工工艺提出两点建议:其一,叶背波纹高度较小和波纹宽度较大,若能保证其中之一,能使得叶型性能下降程度不显著;其二,可根据叶型的低损失攻角范围选择性接受叶背起始加工偏差状态。

Based on the analysis of the local machining quality of the compressor blade,this paper proposes a sine function mathematical model to describe the machining deviation of the waviness aiming at the key parameters describing the waviness.In response to the phenomenon of“small fluctuations”in the blade machining profile,the model effectively and intuitively reflects the height,width and initial phase parameters of the waviness with amplitude,frequency and initial phase.Taking a high-load blade profile of an engine as the object,the influence law and mechanism of the key geometric parameters of waviness deviation on the aerodynamic performance of the high-subsonic blade profile of the compressor are studied by numerical simulation method.The results show that,with the same waviness width and initial phase,the range of angle of attack decreases with the increase of waviness height,and the increase of the local waviness height on the suction side will lead to an increase in flow loss.Poorly machined profiles with large waviness height and small waviness width undergo the most severe performance degradation,and when Ma=0.8,the loss is at least 24.2%higher than the design blade profile.Based on the result,two suggestions are made to the existing processing technology:First,either a smaller waviness height or a larger waviness width shall be guaranteed,which can make the degradation of the blade profile performance not significant;second,the initial machining deviation state of the suction side can be selectively accepted according to the low range of loss for the blade profile.