轴向密流比对叶栅性能影响的研究

轴向密流比是决定叶轮机械叶栅流动工作状态的一个重要参数,它对叶栅诸性能有较大的影响。本文对该问题进行了一些理论及实验方面的研究,推导出了叶栅总压损失系数、尾迹附面层特性参数、叶栅增压比及扩散因子等叶栅性能参数与轴向密流比的关联方程,并对某压气机叶栅进行了吹风实验,得到了不同轴向密流比条件下的叶栅性能。理论计算与实验结果进行了比较,两者的吻合程度是令人满意的,表明本文所得出的理论关联式可以有效地估算轴向密流比对叶栅性能的影响,具有一定的实用价值。

Investigations of the Effects of Axial Velocity Density Ratio on Cascade Performances of the Compressor

The Axial Velocity Density Ratio (AVDR) is significantly to effect cascade performances of compressors.A lot of the experimental researches have indicated this important phenomenon.The empirical correlations given by limited experimental data only present the influence of AVDR on flows of some special cascades.But nearly the same effect of AVDR on cascade deflections have been obtained by many researchers. In this paper,the theoretical correlations of cascade total pressure loss coefficient and characteristic parameters of the wake with AVDR are derived, utilizing the theory of compressible turbulent boundary layers and the assump- tion of a symmetric simple-power velocity distribution in the wake behind cas- cades.The other correlated equations of cascade performances with AVDR are also presented.These equations can be used to evaluate the performances for compressor cascades at various values of AVDR. For comparison,the experiments of a compressor cascade for different AVDR are made by changing the shape of wind tunnel side walls.A fairly good agreement between the theory and experiments is obtained.The theoretical analysis and experimental results show that the effects of AVDR on compressor cascade performances are greatly related to the flow conditions,such as inlet Mach number,incidence angle and deflection.