机动载荷作用下航空发动机机匣结构对叶尖间隙的影响分析

Influence of aero-engine casing structure on tip clearance under maneuvering load

针对机动载荷作用下航空发动机压气机叶尖间隙变化不均匀问题,开展了机动载荷作用下结构因素对叶尖径向间隙的影响研究。以小涵道比涡扇发动机为对象,建立计算模型,通过有限元数值模拟,得到航空发动机压气机机匣和中介机匣在机动载荷作用下对高压压气机叶尖间隙的影响规律。结果表明,采用双层机匣结构能够增加压气机的纵向刚度,减小压气机在法向过载和陀螺力矩作用下的椭圆变形和转静子偏心,使得叶尖间隙变化更为均匀。增加中介机匣的刚性,可以减小压气机内层机匣在法向过载作用下的非对称变形,从而改善压气机叶尖工作间隙特性。机匣结构对压气机叶尖间隙在机动载荷作用下的影响较为显著,通过对机匣结构的改进,可获得0.41%~0.64%的工作间隙减小收益。

To solve the problem of uneven tip clearance variation in aero-engine compressor under maneuvering load,the influence of structural factors on tip radial clearance under maneuvering load was studied.Taking a small bypass ratio turbofan aero engine as an object,a computational model was established.Through finite element numerical simulation,the influence law of aero-engine compressor casing,and intermediate casing on the tip clearance of a high-pressure compressor under maneuvering load was obtained.The results show that the double-layer casing structure can increase the longitudinal stiffness of the compressor,reduce the elliptical deformation and eccentricity of the compressor under normal overload and gyroscopic moment,thus make the tip clearance change more uniform.Increasing the rigidity of the intermediate casing can reduce the asymmetric deformation of the inner compressor casing under normal overload,to improve the working characteristics of the compressor tip clearance.The influence of aero-engine casing structure on compressor tip clearance under maneuvering load is significant.By improving the casing structure,0.41%−0.64%of working clearance reduction benefits can be obtained.