基于重组信号混沌特性的离心式压气机流场诊断方法

Flow Field Diagnosis Method of Centrifugal Compressor Based on Chaotic Characteristics of Recombined Signals

关键词:  离心式压气机  旋转失速  喘振  流场诊断  混沌特性

Key words:  Centrifugal compressor  Rotating stall  Surge  Flow field diagnosis  Chaotic characteristics

摘要:

为了快速、准确地对离心式压气机内复杂三维流场的稳定性进行非接触式诊断，提出了一种可以识别和预判离心式压气机内可能出现的旋转失速或喘振等严重非稳定流动结构的新方法。通过从叶轮出口处盖板侧壁压信号映射的递归图中提取出合适的混沌特性量化指标来实现流场诊断，并利用周向相邻测点信号的预先重组进一步改进了该诊断方法。使用已公开发布的离心式压气机失稳状态下的相关试验数据验证了该流场诊断方法的可行性。相比于常规方法，该方法的优势在于可以通过量化指标更早地预判出压气机内流动失稳，并且指标临界值在各转速下保持基本一致，能够更好地应用于叶轮旋转速度波动或瞬变的突发情况。

Abstract:

To quickly and accurately perform non-contact diagnosis on the stability of the complex three-dimensional flow field in the centrifugal compressor， a new method to identify and predict severely unstable flow structures that may occur in the centrifugal compressor such as rotating stall or surge was proposed. The flow field diagnosis was achieved through extracting a suitable quantified index of chaotic characteristics from the recursive image mapped by the wall-pressure signal on the shroud side at the impeller outlet， and the flow field diagnosis method was further improved by using the pre-recombination of signals at adjacent testing positions in the circumferential direction. The feasibility of this flow field diagnosis method was verified with the help of the published relevant experimental data in the centrifugal compressor under typical unstable conditions. Compared with the conventional methods， the method can predict the flow instability in the compressor earlier through the quantitative indicator， and the indicator threshold remains basically the same at each rotating speed， which makes the method better applicable to the emergency situation of impeller rotating speed fluctuation or transient.