离心压气机内激波/叶排相互作用

对根部存在疲劳裂纹的某跨音离心级进行了非定常流场数值研究,其中着重关注运动激波／叶排相互作用物理图画及其影响。研究表明:离心压气机中运动激波／叶排相互作用仍然服从一般激波／固壁相交行为规则;叶轮／扩压器间距小以及叶轮尾迹相对较宽造成扩压器内激波剧烈变化;扩压器前伸波深入叶轮通道深度由激波强度及扩压器前缘附近叶表形状决定;扩压器前伸波与叶轮尾缘相互作用可能是本叶轮根部尾缘发生高周疲劳的原因。

BLADE INTERACTION BETWEEN SHOCK WAVE AND IMPELLOR

Numerical study about unsteady flow field in one transonic compressor with fatigue crack at impellor hub is presented, in which main interest is focused on mechanism and influence of shock wave/impellor interaction. Results show that shock wave/impellor interaction follows the general law involved in intersection of shock wave and solid wall. Wide wake and small gap between impellor and diffuser make the shock wave in diffuser change rapidly and greatly. These changes include the transformation between shock wave and compression wave, the number of shock wave and large oscillation of shock wave or compression wave in diffuser passages. The deepth that up-extended bow shock of diffuser run into impellor is determined by shock wave strenth and wall shape near the diffuser leading edge.High frequency and large amplitude of stress oscillation induced by up-extended bow shock may lead to high cycle fatigue. This might be the main reason of fatigue crack that takes place at the hub of this impellor.