小型涡轴发动机串列静子数值研究
Numerical investigations of a tandem stator stage for a small turbo-shaft engine
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摘要: 高逆压梯度、复杂端壁流动及厚边界层是高负荷小型压气机的典型特征, 大量叶栅试验表明采用叶片串列的布局形式可以很好地解决叶片高负荷的问题。但过时的设计方法不再能满足高负荷串列静子的设计需求, 小型发动机中串列叶片的流动机制需要进一步研究。本文采用EURANUS对一高负荷跨声速小型压气机进行了数值模拟, 对原始静子进行了改型设计。分析串列静子的迎角、落后角、载荷分配比来发现流动的三维特征, 对比流场来甄别串列静子的性能收益。发现前叶的落后角和后叶的气流迎角对静子来流的迎角变化并不敏感, 前叶承担了几乎全部来流迎角变化所引起的负荷变化;设计点时以串列的方式更为均匀地分配前后叶的载荷, 对级整体性能的提升有益。Abstract: The highly loaded small compressor is typically characterized by the large adverse pressure gradient, the complex endwall flow and the thick boundary layer, and the layout of the tandem blade is a good way to deal with high loading case according to large amounts of cascade experiments. However, dated design methods can't meet the needs for the advanced tandem stator and the flow mechanism should to be understood profoundly in small engines. As a result, a redesigned tandem stator is simulated in a highly loaded transonic small compressor with the commercial solver EURANUS. Incidences, deviations and loading splits of tandem blades are inspected to find the three dimensional characteristics. Contrasts are made to capture the flow field benefits between the tandem stator and the original stator. It is found that both the front blade's deviations and the rear blade's incidences are not sensitive to the incidence variations, and the front blade undertakes the whole incidence variations nearly. It's beneficial to distribute the loading uniformly for highly loading stators at the design point in the manner of tandem layout.