Modelling and Dynamic Mode Analysis of Compressor Impeller Spike-type Stall with Global Stability Approach
Modelling and Dynamic Mode Analysis of Compressor Impeller Spike-type Stall with Global Stability Approach
复制标题
压气机叶轮尖刺型失速的全局稳定性建模与动态模态分析
DOI：
10.1016/j.ijmecsci.2021.106486
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发表时间：
2021
影响因子：
7.3
通讯作者：
Xin Shi
中科院分区：
文献类型：
--
作者：
Ce Yang;Li Fu;Chenxing Hu;Xin Shi
与尖峰失速相关的流动不稳定性是制约先进高速离心压气机发动机发展的重要因素。然而，由于离心压缩机的结构不规则，很少有方法可以用于稳定性分析。针对尖峰失速的典型特征，创新性地提出了一种叶轮进口流场稳定性分析方法。从而深入了解失速扰动结构，准确预测失速扰动的传播。本文采用雷诺平均N-S技术对带蜗壳的离心压气机进行了非定常全环流数值模拟并进行了实验验证。然后，采用一种先进的动态模态分解方法压缩DMD，提取并分析了失速扰动的主导结构。最后，考虑涡粘性和分子粘性的影响，建立了基于叶轮进口θ-z柱面的二维整体稳定性分析方法，揭示了失速扰动的传播行为。结果表明，压缩DMD方法可以准确捕捉失速引起的低频扰动，但不依赖于采样。失速附近的流动结构可以分解为受影响的平均流、与转子频率和叶片通过频率相关的流动扰动（频率分别为1333 Hz和9333 Hz）和失速扰动（频率为510 Hz）。从扰动传播特性来看，它主要是沿θ-z柱面沿着的两次传播。一种是沿轴向向上游的反向传播，另一种是在第一次传播过程中，在主流的影响下，向叶片前缘的二次传播。两条传播路径均向旋转方向偏转，且第二条传播路径的偏转程度大于第一条传播路径的偏转程度，从而形成三角形不稳定区域。该研究不仅为稳定性分析在离心压气机中的应用提供了一种新的思路，而且也阐明了失速扰动的传播特性，为精确的流量控制奠定了基础。
Flow instability associated with spike-stall restricts the development of advanced aero-engines with a high-speed centrifugal compressor. However, given the irregular structure of centrifugal compressor, few approaches can be applied to stability analysis. Considering the typical features of spike-stall, an implement of stability analysis method on the flow field of impeller inlet was proposed innovatively. Thus, in-depth comprehension of stall perturbation structure and accurate prediction of stall perturbation propagation can be obtained. In this work, an unsteady full annular simulation of a centrifugal compressor with a volute coupled with experimental validations was carried out by using the Reynolds averaged Navier–Stokes technique. Then, an advanced dynamic mode decomposition method named compressed DMD was employed to extract and analyze the dominant stall perturbation structure. Finally, considering the effects of eddy viscosity and molecular viscosity, a two-dimensional global stability analysis method based on theθ-zcylindrical surface at the impeller inlet is established to reveal the propagation behaviors of stall perturbation. The results indicate that the compressed DMD approach can capture low-frequency perturbation caused by stall accurately but not dependent on samplings. The flow structure near stall can be decomposed into the influenced mean flow, flow perturbation associated with rotor frequency and blade passing frequency with the frequencies of 1333 Hz and 9333 Hz, respectively, and stall perturbation with the frequency of 510 Hz. In the view of perturbation propagation features, it is mainly two propagations along theθ-zcylindrical surface. One is the reverse propagation to the upstream axially; the other is the secondary propagation to the blade leading edge with the effect of the main flow during the first propagation process. Both propagation paths deflect to the rotation direction, and the deflection degree of the second propagation paths is larger than that of the first one, thus, a triangular instability region is formed. The researches not only provide a new thought for the application of stability analysis in the centrifugal compressor but also clarify the propagation characteristics of stall disturbance, which lays a foundation for accurate flow control.