Transition Process from Diffuser Stall to Stage Stall in a Centrifugal Compressor with a Vaned Diffuser
Transition Process from Diffuser Stall to Stage Stall in a Centrifugal Compressor with a Vaned Diffuser
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DOI：
10.1155/2017/2861257
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发表时间：
2017-05
影响因子：
0.9
通讯作者：
N. Fujisawa;Y. Ohta
中科院分区：
文献类型：
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作者：
N. Fujisawa;Y. Ohta
通过实验和数值分析，研究了带叶片扩压器离心压气机扩压器旋转失速向级失速的转变过程。从速度测量结果可以看出，在非设计工况下，扩压器通道的围带侧存在旋转失速。数值计算结果揭示了扩压器失速的典型涡系结构。扩压器失速单元是由系统涡结构引起的，系统涡结构包括龙卷风型涡、围带/吸力面角部的纵向涡（即，前缘涡流（LEV））和扩压器通道喉部区域的涡流。此外，随着质量流量的减小，在叶轮和扩压器通道内旋转的级失速发生，而不是扩压器失速。根据扩压器进口处的速度测量结果，扩压器失速从叶冠侧转向轮毂侧。然后，扩压器失速进入叶轮通道，形成级失速。因此，级失速是由扩压器失速的发展引起的，扩压器失速在无叶空间中从围带侧转移到轮毂侧，并扩展到叶轮通道。
The transition process from a diffuser rotating stall to a stage stall in a centrifugal compressor with a vaned diffuser was investigated by experimental and numerical analyses. From the velocity measurements, it was found that the rotating stall existed on the shroud side of the diffuser passage in the off-design flow condition. The numerical results revealed the typical vortical structure of the diffuser stall. The diffuser stall cell was caused by the systematic vortical structure which consisted of the tornado-type vortex, the longitudinal vortex at the shroud/suction surface corner (i.e., leading edge vortex (LEV)), and the vortex in the throat area of the diffuser passages. Furthermore, the stage stall, which rotated within both the impeller and diffuser passages, occurred instead of the diffuser stall as the mass flow rate was decreased. According to the velocity measurements at the diffuser inlet, the diffuser stall which rotated on the shroud side was shifted to the hub side. Then, the diffuser stall moved into the impeller passages and formed the stage stall. Therefore, the stage stall was caused by the development of the diffuser stall, which transferred from the shroud side to the hub side in the vaneless space and expanded to the impeller passages.