叶轮机通流模型周向脉动应力项建模及分析

Modeling and Analysis of the Circumferential Fluctuation Stresses in Turbomachinery Throughflow Model

为了模化周向平均通流模型中的周向脉动应力项,一种基于势流分析的代数方法被提出,并被整合到通流模型中。通过对具有不同弯角、不同迎角以及不同来流马赫数的叶栅开展三维数值模拟和通流计算,分析结果表明:主要由无黏叶片力所诱发的周向不均匀性会重新组织叶片通道的进口流场,进而改变迎角。并且,随着负荷或马赫数的提高,这种周向不均匀性将加强,其对流动的影响也会进一步提升。加入该代数模型后,通流模型能够很好地实现对周向不均匀性的预测,周向脉动源项在前缘前与三维结果的偏差在5%以内,对叶片通道进口气流角改变量的预测精度提高了50%以上。

To model the circumferential fluctuation stresses in throughflow models based on circumferential average method, an algebraic method based on potential analysis was proposed and integrated into a throughflow model. Three-dimensional（3 D） numerical simulations and throughflow numerical simulations of cascades with different cambers, different incidence angles and different inlet Mach numbers were carried out. Analysis of the results indicates that the circumferential non-uniformity mainly induced by the inviscid blade force will rearrange the flow field at the inlet of the blade passage and thus alter the incidence angle. Moreover, the circumferential non-uniformity and its influence on the flow field are enhanced with the increase of blade loading or Mach number.With the algebraic method included, the throughflow model can offer a good prediction of the circumferential non-uniformity for these cases, and the discrepancy of the circumferential fluctuation source terms between 3 D results is within 5% before the leading edge. Besides, the prediction accuracy of the variation of the flow angle before the inlet of the blade passage is increased over 50 percent.