叶栅三维流场的实验研究

本文通过流动显示和详细测量,研究了叶栅中的三维流动。在平面叶栅风洞中,对非平直端壁的大弯度压气机叶栅所完成的测量,包括沿叶高的叶型表面上气流参数分布和叶栅通道中的整个流场。为了进行对比和详细研究端壁效应,还对二维叶栅完成了同样的测量内容。对所观察到的复杂流动现象进行了分析。实验结果还与叶栅全三维无粘流计算进行了对比。本文所获得的完整的三维流场实验数据,为建立叶栅流动模型,研究小展弦比叶栅中气流展向掺混的机理,以及为检验全三维流动计算方法提供了可靠的依据。 

AN EXPERIMENTAL STUDY OF 3-D FLOW IN A CASCADE

An experimental investigation of three dimensional flow in a cascade has been accomplished by means of flow visualization and detailed measurements,and also compared with the predictions of fully three dimensional inviscid flow calculation.The experimental measurements of the three dimensional flow in a highly cambered compressor cascade with nonplanar end wall reveal the distributions of flow parameters on blade surfaces and the whole flowfield in cascade channel.In comparison with the two dimensional cascade measurements for the same blade section,the results show that the influence of the end wall shape changing on the flow is not confined to the vicinity of end walls,and can extend to the whole field when the aspect ratio of blading is small.The comparison between the experimental data and the computational results confirms that the inviscid flow calculation can predict the major features of three dimensional flow in cascades.The flow visualization reveals the formation and development of vortex systems in the cascade passage,end wall and corner regions,which serve as a visualized information to understand the phenomena of complicated secondary flow in cascades.The experimental measurements provide a reliable basis to perfect the flow models,to investigate the mechanism of spanwise mixing in a cascade and to testify the capabilities of fully three dimensional cascade flow calculation methods.