对圆柱和二维扩压叶栅在平面叶栅风洞中旋涡脱落的试验研究

随着叶轮机设计技术的发展，对流动非定常的了解显得越来越急迫。而在叶轮机的流动中，尾流是导致流动非定常的一个重要因素，因此对尾流流动特性的研究就显得很有必要。本文在不同的平面叶栅风洞中对圆柱及二维扩压叶栅进行了吹风实验，利用传声器、热线热膜以及动态压力传感器等动态测试仪器，对圆柱和二维扩压叶栅后旋涡脱落情况进行了试验研究。实验结果显示，在平面叶栅风洞内的圆柱体尾流中有类似在外流中的卡门涡街脱落现象．但所对应的斯特劳哈数比外流稍小。更重要的是，还首次得到了二维扩压叶栅后明显的旋涡脱落特征频率，证实了在二维扩压叶栅非定常流动中也伴随着有规律的旋涡脱落。这些结果将为利用外流的成果和更全面地考虑叶轮机的气动设计提供很重要的参考作用。

A study on vortex shedding frequency of blade profile and cylinder in cascade tunnel

There is a paradox that the flow in the turbomachinery is unsteady inherently, but the design system of turbomachinery base on steady flow. In order to do some work for resolveing this paradox,as a begin,an aerodynamics test was executed on compressor blade profile and cylinder in plane cascade tunnel. The test showed that there are Karman vortex street behind cylinder ,but the rule of shedding frenquency as strouhal number is defferent compared with that the cylinder is put into outflow.It is very important that the result of test confirmed the existence of regular shedding vortex in two-dimensional compressor blade's wake. The frequency of vortex shedding is changed with Mach number and incidence.