低速模拟设计技术在大小叶片压气机中的应用

Low-Speed Similarity Design for a Compressor Stage with Splittered Rotor

针对一个用于高压压气机出口级的高负荷大小叶片压气机进行了四级重复级试验台低速模拟设计研究,探讨了高负荷情况下重复级特征不明显的亚声速级压气机的低速模拟设计方法,以及考虑大叶片和小叶片气动耦合的低速模拟设计方法。研究过程中,通过调整静子叶片的稠度和弯角,采用静子叶片更大程度的几何不相似保证了模拟级转子的低速模拟设计达到高低速转换标准,并保证在不同工况下转静子的匹配关系不发生改变。此外,通过确保大叶片和小叶片叶表无量纲速度相似,并适当调整小叶片的安装角,成功模拟了高速环境下大/小叶片之间的气动耦合效应。三维数值验算结果表明,低速模拟设计得到的设计和非设计工况内部流场和压气机特性都与高速原型具有较好的相似性。

Low similarity design was conducted for a highly loaded high speed high pressure compressor outlet subsonic stage designed with splittered rotor and has distinct discrepancy of the inlet and outlet flow angles. Considering that the low-speed compressor test was designed with four repeating stage configuration, the way to using repeating stage low-speed compressor to simulate the flow in the high speed prototype compressor without repeating stage flow was discussed. Moreover, in the splittered rotor, the flow coupling effects between the pri- mary and splitter blades are significant, which was also carefully considered in the low-to-high speed design process. To deal with the aforementioned problems, the way to using much strong ＂non-similarity geometry＂ design methods in the low-speed stator to guarantee the strict high-to-low speed design for the splittered rotor was adopted. The blade solidity and camber angle of the low-speed stator increased much to produce the repeat- ing stage flow in the low-speed test but with the same flow diffusion strength and rotor-stator matching character- istics in the low and high speed compressors. Moreover, for the low-speed design of the splittered rotor, in or- der to guarantee the similarity of the blade surface nondimensional velocity distributions and the flow coupling ef-fects of the primary and splitter blades between the high and low speed blades, the low-speed splitter blade was designed with a relatively smaller stagger angle comparing to the high speed one. Finally, the specific flow fields and the compressor performance for the high and low speed compressors were compared in detail by using the three-dimensional numerical simulations results. The results showed that the low speed similarity design was suc- cessful.