The Role of Tip Leakage Vortex Breakdown in Flow Fields and Aerodynamic Characteristics of Transonic Centrifugal Compressor Impellers
The Role of Tip Leakage Vortex Breakdown in Flow Fields and Aerodynamic Characteristics of Transonic Centrifugal Compressor Impellers
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DOI：
10.1115/gt2011-46253
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发表时间：
2011
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影响因子：
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通讯作者：
Kazutoyo Yamada;M. Furukawa;H. Fukushima;S. Ibaraki;I. Tomita
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文献类型：
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作者：
Kazutoyo Yamada;M. Furukawa;H. Fukushima;S. Ibaraki;I. Tomita
本文对两种不同气动特性的跨音速离心压气机叶轮内的三维非定常流场进行了实验和数值研究。在实验结果中，压力波动的频谱，这是测量与高响应压力传感器安装在壳体壁的叶轮上游，原来是完全不同的压气机叶轮之间的失速状态。模拟结果还显示了不同压气机叶轮的不同失速模式。在非设计工况下性能较好的压气机叶轮中，尽管流量降低，但失速区始终未形成，而是在叶尖附近被一股反向流动所覆盖，在全叶片的叶尖泄漏涡中发生涡破裂，导致叶轮的非定常性。在失速前，所有通道都发生了涡破裂，并在叶尖附近产生了阻塞。这意味着，即使出现旋转失速，在非失速区域，流动也不能恢复到正常的无畸变状态，因为所有通道都已被涡流破裂造成的堵塞物占据。因此，叶轮内不会出现旋转失速胞。在另一个压气机叶轮中，旋转失速胞在失速开始时形成，在整个叶片的顶部泄漏涡中没有涡破裂，并且随着流量的减小而发展。
This paper describes the experimental and numerical investigations on unsteady three-dimensional flow fields in two types of transonic centrifugal compressor impellers with different aerodynamic characteristics. In the experimental results, the frequency spectra of the pressure fluctuations, which were measured with the high-response pressure transducers mounted on the casing wall just upstream of the impeller, turned out to be quite different between the compressor impellers at stall condition. The simulation results also showed different stall pattern for each compressor impeller. In the compressor impeller with a better performance at off-design condition, the stall cell was never formed despite decreasing flow rate and instead all the passages were covered with a reverse flow near the tip, where the vortex breakdown happened in the tip leakage vortex of full blade and led to the unsteadiness in the impeller. The vortex breakdown happened in all the passages prior to the stall and generated a blockage near the tip. This means that even with the advent of rotating stall the flow could not return to a normal undistorted condition in unstalled region, because all the passages are already occupied by the blockage due to the vortex breakdown. As a result, the rotating stall cell could not appear in the impeller. In the other compressor impeller, the rotating stall cell was formed at stall inception without the vortex breakdown in the tip leakage vortex of full blade, and developed with decreased flow rate.Copyright © 2011 by ASME