Rotating Instability in an Annular Cascade: Detailed Analysis of the Instationary Flow Phenomena
Rotating Instability in an Annular Cascade: Detailed Analysis of the Instationary Flow Phenomena
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DOI：
10.1115/1.4025734
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发表时间：
2013-06
影响因子：
1.7
通讯作者：
B. Pardowitz;U. Tapken;R. Sorge;P. Thamsen;L. Enghardt
中科院分区：
文献类型：
--
作者：
B. Pardowitz;U. Tapken;R. Sorge;P. Thamsen;L. Enghardt
旋转不稳定性（RI）发生在压气机的非设计工况下，主要发生在叶尖或轮毂间隙比大于3%的构型中。RI是叶尖涡流噪声的来源，也是旋转失速和喘振等临界运行条件的潜在指标。本文的目的是给更多的物理洞察RI现象的分析结果相结合的近场测量与高速粒子图像测速（PIV）和非定常压力传感器。研究对象是一个带有轮毂间隙的环形叶栅。捕捉到了前缘附近的非定常流场以及相关的旋转压力波。一种特殊的分析方法示出了特征压力波振幅分布，表示为RI的“模态事件”。此外，稍微修改的方法揭示了对应于RI的非定常流动结构。流动剖面，占主导地位的涡结构，和旋转的压力波之间的相关性被发现。结果提供了证据，一个新的假说，这意味着剪切层不稳定性构成的RI的基本机制。
Rotating instability (RI) occurs at off-design conditions in compressors, predominantly in configurations with large tip or hub clearance ratios of s* �> 3%. RI is the source of the blade tip vortex noise and a potential indicator for critical operating conditions like rotating stall and surge. The objective of this paper is to give more physical insight into the RI phenomenon using the analysis results of combined near-field measurements with high-speed particle image velocimetry (PIV) and unsteady pressure sensors. The investigation was pursued on an annular cascade with hub clearance. Both the unsteady flow field next to the leading edge as well as the associated rotating pressure waves were captured. A special analysis method illustrates the characteristic pressure wave amplitude distribution, denoted as “modal events” of the RI. Moreover, the slightly adapted method reveals the unsteady flow structures corresponding to the RI. Correlations between the flow profile, the dominant vortex structures, and the rotating pressure waves were found. Results provide evidence to a new hypothesis, implying that shear layer instabilities constitute the basic mechanism of the RI.