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使用数值研究方法研究了三个机器马赫数(Mu)下,小尺寸离心叶轮叶片前缘采用长短轴比例分别为1:1,2:1,3:1,4:1的椭圆形(圆形前缘可认为长短轴比为1:1)时叶片前缘附近流场情况及不同前缘形状对压缩机气动性能的影响(Mu主要应用于工程中,在离心压缩机中是用来衡量叶轮转速的一个无量纲量)。结果表明,椭圆形前缘随着长短轴比例的增大,可有效减小叶轮入口处的分离损失,使压缩机性能明显提高,喘振裕度及工作范围没有明显变化,并对结果进行了实验验证。经过静力分析,叶片前缘椭圆形长短轴比例的增加对叶轮强度影响不大。在小尺寸叶轮的设计和加工中,如压缩机在正常叶轮入口机器马赫数下运行(Mu=0.95附近),叶轮叶片前缘椭圆形长短轴比例对压缩机性能略有影响,可折衷考虑加工效率和压缩机性能;如压缩机在叶轮入口机器马赫数较高工况下运行较多(Mu大于1),叶轮叶片前缘椭圆形长短轴比例对压缩机性能影响较为显著,可将比例选为3:1或4:1。
Using the numerical method to study Mach number (Mu) of three machines, the leading edge of a small-sized centrifugal impeller blade has an elliptical shape with a ratio of major axis to minor axis of 1: 1,2: 1,3: 1,4: 1 The leading edge can be considered as the ratio of the long axis to the short axis is 1: 1), the flow field around the leading edge of the blade and the influence of different leading edge shapes on the aerodynamic performance of the compressor (Mu is mainly used in engineering, centrifugal compressor is used to measure the impeller A dimensionless quantity of speed). The results show that with the increase of the ratio of the major axis to the minor axis, the elliptical leading edge can effectively reduce the separation loss at the inlet of the impeller, improve the performance of the compressor obviously, and have no obvious changes in the surge margin and the working range. Experimental verification. After static analysis, the increase of the ratio of the major axis to the minor axis of blade leading edge has little effect on the strength of the impeller. In the design and processing of small-sized impellers, if the compressor operates at Mach number of the normal impeller entrance machine (Mu = 0.95), the ratio of the major axis to the minor axis of the leading edge of the impeller has a slight effect on the performance of the compressor. Efficiency and compressor performance. For example, when the compressor operates at a higher Mach number of the inlet of the impeller (Mu is greater than 1), the ratio of the major axis to the minor axis of the leading edge of the impeller blade has a significant effect on the performance of the compressor. 3: 1 or 4: 1.