Three-dimensional analysis of blade force and sound generation for an annular cascade in distorted flows
Three-dimensional analysis of blade force and sound generation for an annular cascade in distorted flows
复制标题
DOI：
10.1016/0022-460x(77)90498-9
复制
发表时间：
1977-02
影响因子：
4.7
通讯作者：
M. Namba
中科院分区：
文献类型：
--
作者：
M. Namba
建立了旋转亚音速环形叶栅的非定常升力面理论，用来预测叶片与进口扭曲或尾迹相互作用所产生的非定常叶轮力和声功率。用叶片力分布和核函数表达了叶轮力脉动引起的扰动压力场和速度场。叶片力的横向分布表示为叶片力模式的总和，核函数分解为相应的模式分量。声压和声强用声学振型之和表示，各振型的振型分量由叶片力振型分量表示。对于与周向为正弦但在径向具有相位偏斜的外部扰动流的相互作用，进行了数值计算。研究了声学振型、叶片力振型和外扰流流型之间的关系。当主声振型为次共振时，三维效应使叶片力幅减小，并随着频率的增加而减小。然而，在深度超共振态下，三维效应对叶片力幅值的展向平均值的影响很小。通过增加外部扰动的径向不均匀性，有效地降低了产生的声功率。
An unsteady lifting-surface theory for a rotating subsonic annular cascade has been developed to predict the unsteady blade forces and the acoustic power generation caused by interaction of blades with inlet distortions or wakes. Disturbance pressure and velocity fields induced by the rotor blades with fluctuating blade force are expressed in terms of the blade force distribution and kernel functions. The spanwise distribution of the blade force is given as a sum of blade force modes, and the kernel functions are resolved into the corresponding modal components. The sound pressure and intensity are expressed as a sum of acoustic modes, the modal components of which are given in terms of the blade force mode components.Numerical computations have been conducted .for interaction with the external disturbance flows that are sinusoidal in the circumferential direction, but possess a phase skewing in the radial direction. Correlations among the acoustic modes, the blade force modes and the flow patterns of the external disturbance have been investigated. When the predominant acoustic mode is subresonant, the blade force amplitude is reduced by the three-dimensional effect, which is lessened as the frequency increases. At deeply superresonant states, however, the three-dimensional effect upon the spanwise average of the blade force amplitude is small. The generated sound power is effectively reduced by increasing the radial non-uniformity of the external disturbance.