Numerical Modeling of the Dynamic Unsteadiness with Global Mode Decomposition Approach in a High-speed Compressor with Abnormal Diffuser Vane
Numerical Modeling of the Dynamic Unsteadiness with Global Mode Decomposition Approach in a High-speed Compressor with Abnormal Diffuser Vane
复制标题
具有异常扩压器叶片的高速压气机动态不稳定性的全局模态分解数值模拟
DOI：
10.1177/09544070221107805
复制
发表时间：
2022-07
期刊：
影响因子：
--
通讯作者：
Ce Yang
中科院分区：
文献类型：
--
作者：
Chenxing Hu;Ce Yang
可调叶片扩压器是离心压缩机寻求更大稳定裕度的主要技术之一。然而，流动不稳定性可能是由扩散器中的异常叶片引起的三维流动分离驱动的。本文对带异形叶片的径向扩压器进行了数值模拟，研究了扩压器失速起始与非对称流场之间的关系。对带叶片扩压器的离心压气机进行了非定常数值模拟，并与实验数据进行了对比验证。采用压缩动力学模态分解方法，从扰动频率和主导模态两个方面分析了扩压器内流动不稳定性的气动特性和演化过程。最后，从失速机理的角度，从蜗壳舌部与异形叶片的相对位置角度，总结了异形叶片对扩压器与蜗壳匹配的影响。结果表明，在叶轮发生尖峰失速之前，需要对异形叶片进行10°以上的大角度偏转，才能触发扩压器内部流动的不稳定性。随着安装角变化的增加，失速机理由多通道内的整体流动分离转变为有限通道内的局部突变现象。采用模态合成法分析发现，扩压器出口附近的流动分离和异形叶片前缘的龙卷风型涡是导致15°叶片交替情况下流动不稳定性的主要原因。当与蜗壳组合时，靠近蜗舌处的异常叶片比远离蜗舌180°处的异常叶片更容易失稳。在非对称蜗壳的影响下，龙卷风型涡也向后缘而不是前缘移动。
Adjustable vane diffuser is addressed as one of the main techniques in centrifugal compressor in seeking of wider stability margin. Flow instabilities, however, may be driven by the three-dimensional flow separation induced by the abnormal vane in the diffuser. In the present work, a numerical investigation of the radial vaned diffuser with abnormal vane was applied to identify the correlation between stall inception and asymmetric flow distribution. Unsteady numerical simulations of the centrifugal compressor with vaned diffuser was carried out and validated against experimental data. Then, the aerodynamic characteristics and evolution process of the flow instabilities in vaned diffuser was analyzed with the compressed dynamic mode decomposition in term of perturbation frequency and dominating flow mode. Finally, concerning the relative position of the volute tongue and abnormal vane, the influence of the abnormal vane on the matching between the diffuser and volute regarding the stall mechanism was summarized. The results indicate that the abnormal vane needs to be altered large enough, which is above 10°, to trigger the flow instability of vaned diffuser before the spike stall in impeller. With the increase of stagger angle alternation, the stall mechanism turns from a global flow separation in multiple passages into a regional and abrupt phenomenon in limited passages. With the mode composition approach, the flow separation near diffuser outlet and the tornado-type vortices at the leading edge of the abnormal vane are responsible for the flow instability of the case with 15° vane alternation. When combined with the volute, the case with abnormal vane close to the volute tongue tends to be more unstable than that 180° away from volute tongue. The tornado-type vortices are also moved to the trailing edge rather than the leading edge under the influence of the asymmetric volute.
登录
查看更多内容
DOI：
10.1115/gt2018-75462
发表时间：
2018-06
期刊：
Journal of Turbomachinery
影响因子：
--
作者：
N. Fujisawa;T. Inui;Y. Ohta
通讯作者：
N. Fujisawa;T. Inui;Y. Ohta
影响因子：
8.7
作者：
Hui Meng;Meihong Wang;Olumide Olumayegun;Xiaobo Luo;Xiaoyan Liu
通讯作者：
Hui Meng;Meihong Wang;Olumide Olumayegun;Xiaobo Luo;Xiaoyan Liu
影响因子：
6.4
作者：
Zhenzhong Sun;Xinqian Zheng;T. Kawakubo
通讯作者：
Zhenzhong Sun;Xinqian Zheng;T. Kawakubo
影响因子：
3
作者：
Brunton, Bingni W.;Johnson, Lise A.;Kutz, J. Nathan
通讯作者：
Kutz, J. Nathan
影响因子：
5.6
作者：
A. Zamiri;Byungju Lee;J. Chung
通讯作者：
A. Zamiri;Byungju Lee;J. Chung