Abstract: Numerical investigation of a highly loaded centrifugal compressor with wedge diffuser was performed and the result matches well with test data. Then，pipe diffusers with different throat length and divergence angle were designed and parametric studies of pipe diffuser throat length and divergence angle were carried out with the validated numerical method. It is found that long pipe diffuser throat length could decrease compressor performance at design point but could depress diffuser flow separation near surge. Performance is better when the ratio of throat length to throat diameter is 0.5. More loss could be caused by flow separation in pipe diffuser with larger divergence angle. The stage efficiency drops about 3% when divergence angle enlarges from 4°to 12°.

Key words: Centrifugal compressor；Pipe diffuser；Numerical simulation

摘要： 针对带楔形扩压器的高负荷离心压气机，利用数值模拟手段对其进行了研究，计算获得的离心压气机特性与试验结果符合较好。在此基础上，设计了具有不同喉部长度和扩张角的管式扩压器，利用经过校核的数值模拟手段对管式扩压器的喉部长度和扩张角进行了参数化研究。研究发现较长的喉部会使压气机设计点的性能下降，但是却可以抑制近失速点扩压器内的流动分离，喉部长度与喉部直径之比为0.5时综合性能较优；较大的扩张角会造成扩压器内流动分离，增加流动损失，扩张角由4°增加到12°时压气机效率降低了约3%。

关键词: 离心压气机；管式扩压器；数值模拟