下游畸变对压气机性能影响的预测

INFLUENCE OF DOWNSTREAM DISTORTION ON PERFORMANCE OF AXIAL COMPRESSOR

高技术航空发动机因结构紧凑、气动耦合密切而面临着下游畸变问题 ,影响压气机的性能 ,因而有必要研究下游畸变对压气机特性和喘振裕度的影响。本文提供了一种预测轴流压气机出口流场畸变对其特性和喘振裕度影响的方法 ,并具体分析了下游周向总压畸变对某单级轴流压气机特性和喘振裕度的影响。结果表明临界失速的流量系数损失和压比损失均与畸变系数呈线性变化关系 。

The development of a new method to predict the unstalled characteristics and the onset of flow instability is described for an axial compressor operating in a circumferentially distorted downflow.This method adopts the“semi-actuator disk”to replace the blade rows of the compressor and the downstream distorting component,and assumes the flow fields outside the disks to be two-dimensional,ideal,compressible and unsteady.The effects of total pressure distortion coefficient and spacing between the compressor and the distorting component on the performance of a compressor have been investigated in detail by means of this method.It is found that the losses of both pressure rise and axial flow coefficient at instability increase linearly with the distortion coefficient,this conclusion is similar to that for the inlet flow distortion.And the spacing has crucial effect on the losses of both pressure rise and axial flow coefficient too.