延长叶轮盘、盖尺寸对离心压缩机模型级性能影响研究（英文）

Effect of Impeller Extended Hub and Shroud on Centrifugal Compressor Stage Performance

CFD method was employed to analyze the effect of the wall extension of hub and shroud at the impeller outlet(rotating diffuser)in a centrifugal compressor model stage with a large mass flow coefficient.The effect of clearance leakage was considered.Results show that the extended hub and shroud increases the head coefficient and ploytropic efficiency for the centrifugal compressor stage,and the extension length is longer,the head coefficient and ploytropic efficiency is higher.When extension length is under 4.44%impeller outlet diameter(R2),the increase rate of head coefficient and polytropic efficiency is rapid.When the extension length is beyond 4.44%R2,the rate is slowed down.The uniformity at the diffuser inlet is to be improved,the total pressure loss of stationary parts decreases,and then the performance of stage is improved.The total pressure loss of stationary parts starts to reduce with the increase of mass flow coefficient when the extension length exceeds 5.56%R2 and mass flow coefficientis beyond the design value of 0.1957.