At present, off-design centrifugal compressor suffers from great instabilities, such as rotating stall and surge, which lead to work failure, strong pressure fluctuations, and violent vibrations of the entire system. One cause of these instabilities is the rotating stall occurring in vaneless diffuser. In this review, recent researches on rotating stall of vaneless diffuser in centrifugal compressor are reviewed, and its inductive mechanism and characteristic description are emphatically introduced. In vaneless diffuser, the rotating stall starts up and fully develops under non-design conditions with the characteristic of increasing pressure fluctuation amplitude. The negative effects of rotating stall include reverse flow and vortex, both of which have significant effects on the instability of centrifugal compressors. Some improvement methods of rotating stall are also introduced, and a lot of examples are given. Finally, some suggestions and discussions are put forward for the future work.

中文翻译：

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离心压缩机无叶扩压器旋转失速研究述评

目前，设计不当的离心压缩机存在很大的不稳定性，例如旋转失速和喘振，这会导致工作失败，强烈的压力波动以及整个系统剧烈的振动。这些不稳定性的原因之一是在无叶片扩压器中发生了旋转失速。综述了离心式压缩机无叶扩压器旋转失速的最新研究，重点介绍了其感应机理和特性描述。在无叶片扩压器中，旋转失速启动并在非设计条件下充分发展，其特点是压力波动幅度增大。旋转失速的负面影响包括逆流和涡流，它们都对离心压缩机的不稳定性产生重大影响。还介绍了旋转失速的一些改进方法，并给出了很多例子。最后，对以后的工作提出了一些建议和讨论。