Stall Warning by Blade Pressure Signature Analysis
Stall Warning by Blade Pressure Signature Analysis
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DOI：
10.1115/1.4006426
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发表时间：
2011
影响因子：
1.7
通讯作者：
A. Young;I. Day;G. Pullan
中科院分区：
文献类型：
--
作者：
A. Young;I. Day;G. Pullan
在低质量流率下，轴流压缩机遭受导致失速和喘振的流动不稳定性。这些不稳定性的起始过程在过去已经被广泛研究-主要是为了预测或避免失速的发生。最近，人们的注意力已经转移到失速之前的状态，并集中在转子尖端区域叶片通过信号的不规则程度上。通常，随着通过压缩机的流率减小，不规则性的强度增加。人们曾试图根据气流不规则性的程度来制定失速警告/避免程序，但很少努力去描述不规则性本身，或了解其根本原因。该项目的工作首次揭示了叶片通过信号中不规则性的增加高度依赖于叶尖间隙尺寸和偏心率。在叶尖间隙小、均匀的压气机中，伴随着流量减小的叶片通过不规则性的增加将是适度的。然而，如果叶尖间隙增大，则在所有周向位置处的不规则性将急剧上升。在具有偏心叶尖间隙的压缩机中，不规则性的增加将仅发生在叶尖间隙最大的环部分中，而与平均间隙水平无关。本文还讨论了在失速前流场中观察到的不规则性是由于随机紊流还是由于某种形式的相干流结构。详细的流量测量表明，后者是这种情况。从这些发现中可以清楚地看出，基于叶片通过特征不规则性的失速警告系统很难在航空发动机中实施，因为叶尖间隙尺寸和偏心度在每个飞行循环和压缩机寿命期间都会发生变化。© 2013美国机械工程师协会。
At low mass flow rates, axial compressors suffer from flow instabilities leading to stall and surge. The inception process of these instabilities has been widely researched in the past---primarily with the aim of predicting or averting stall onset. In recent times, attention has shifted to conditions well before stall and has focused on the level of irregularity in the blade passing signature in the rotor tip region. In general, the irregularity increases in intensity as the flow rate through the compressor is reduced. Attempts have been made to develop stall warning/avoidance procedures based on the level of flow irregularity, but little effort has been made to characterize the irregularity itself, or to understand its underlying cause. Work on this project has revealed for the first time that the increase in irregularity in the blade passing signature is highly dependent on both tip-clearance size and eccentricity. In a compressor with small, uniform, tip-clearance, the increase in blade passing irregularity that accompanies a reduction in flow rate will be modest. If the tip-clearance is enlarged, however, there will be a sharp rise in irregularity at all circumferential locations. In a compressor with eccentric tip-clearance, the increase in irregularity will only occur in the part of the annulus where the tip-clearance is largest, regardless of the average clearance level. In this paper, some attention is also given to the question of whether the irregularity observed in the prestall flow field is due to random turbulence or to some form of coherent flow structure. Detailed flow measurements reveal that the latter is the case. From these findings, it is clear that a stall warning system based on blade passing signature irregularity would be difficult to implement in an aero-engine where tip-clearance size and eccentricity change during each flight cycle and over the life of the compressor. © 2013 American Society of Mechanical Engineers.