双级对转压气机轴向间隙对性能的影响

Investigation into effects of axial spacing on performance of a dual-stage counter-rotating compressor

设计了7组不同轴向间隙的对转压气机几何数据,应用数值模拟手段获取其性能和流场细微结构,研究了对转转子轴向间距对压气机性能、进气角以及流场结构的影响.结果表明:①在轴向间隙从30%C(C为转子叶片根部弦长)到70%C增加的过程中,对转压气机峰值效率降低2%左右,上、下游对转转子峰值效率也降低约4%;②设计转速下近失速点效率和流量先上升后降低,在55%C间距时达到最大值;堵塞点流量增加,效率降低约3%;③在堵塞工况下,随着轴向间隙的增加上、下游转子进口气流角减小;④当轴向间隙增大至50%C时,继续增大对上下游转子来流攻角影响不大;⑤如果掺混损失占主导地位,通过减小轴向间距可有效提高压气机性能,如果是二次流损失占主导地位通过增加轴向间距来提高压气机性能是可行的方法.

Seven modules with different axial spacings between two reversed rotating ro tors of a counter-rotating compressor were designed,and then the detailed flow structure and performance of them in different rotating speeds was obtained by numerical simulations. The effect of axial spacing on performance of the counter rotating compressor,inlet flow angle of two rotors and flow structure have been investigated. When the axial spacing between two reversed rotating rotors was changed from 30% to 70%C,the following observations were obtained： （1）The peak efficiency of counter-rotating compressor decreased approximately 2%,the efficiency of two reversed rotating rotors decreased approximately 4%. （2）At the near stall condition with designed rotating speed, the efficiency and mass flow rate increased firstly and then decreased, and the maximum of the two parameters happened when the axial spacing was 55%C. （3）At the chock condition,the inlet flow angle of the two rotors decreased,contrary to the trend of the chock mass flow rate change. （4）When the axial spacing was bigger than 50%C,it could not affect the inlet flow angle of the two rotors noticeably. （5）Decreasing the axial spacing can improve the performance of the counter rotating com pressor when the loss of mixing is dominating. If the secondary flow loss is the primary loss,increasing the axial spacing is feasible to improve the performance of the counter-rotating compressor.