非对称激励对叶栅流场时空结构及特性的影响

Effect of asymmetric exciting on space-time structure and characteristic of cascades

基于非定常耦合流动的研究采用导叶非对称周向分布时,可以通过非对称尾流撞击效应实现比对称周向分布更好的气动性能.为了探索非对称激励下的非定常耦合流动特点,首先以单个槽道的时间非均匀射流激励形成的间歇耦合流动研究为基础,分析了时间非均匀激励对二维叶栅流场时空结构的影响.然后通过对采用非对称导叶的某低速轴流压气机的叶中截面二维流场进行1/4周的数值模拟,分析了周向非均匀分布导叶对下游转子流场时空结构的影响,最后通过实验对前面所得到的结论进行验证.认为通过周向非均匀导叶实现流场的耦合流动时,激励区的长度决定了激励效果的好坏,而缓冲区内加入离散导叶可以提升转子流场时空结构品质改善压气机性能.

Based on the unsteady cooperative flow, when the exciting frequency was kept, asymmetric wake impact effect （WIE） could make better performance than the symmetric circumferential distribution. The author studied the mechanism of the asymmetric WIE. Firstly, the way of intermittent cooperative flow caused by intermittent jet in one passage was discussed to learn the trait of the intermittent cooperative flow. Secondly, a two-dimensional computational fluid dynamic （CFD） simulation of a 1/4 low speed compressor mid-span flow field was analyzed. The space-time structure of the compressor was studied. And then the asymmetric inlet guide vane （IGV） affection on that was studied. Thirdly, an experiment was designed to prove the result get from the former research. The result is the circumferential distribution of IGV decides the space-time structure of the downstream rotor flow field. The length of the excitation decides the effect of the WIE, and the dispersed IGV can improve the quantity of the space-time structure of the flow field and reduce the loss of the compressor.