跨声速轴流压气机的失速发展机理

为了研究跨声速轴流压气机由近失速工况发展为失速工况的动态演化机理,对跨声速轴流压气机转子NASA Rotor 37进行了多通道全三维数值模拟,着重分析了激波及前缘溢流对失速发展的影响。结果显示:在峰值效率工况下,叶片通道内存在一道斜激波;在失速工况下,斜激波演化为脱体激波。泄漏涡通过脱体激波后发生破碎,破碎的泄漏涡在向通道下游发展的过程中,受逆压梯度的影响,在通道中部形成一个明显的涡结构。在失速工况初期,由于泄漏涡的自维持现象,前缘溢流现象随着叶顶阻塞区的周期性发展而间歇性出现;随着流量的降低,通道阻塞程度逐渐增加,会出现前缘溢流一直存在的现象,这一特性可以作为流场开始急剧恶化的标志。

Mechanism of stall development in a transonic axial compressor

Three-dimensional multi-passage numerical simulations on the NASA Rotor 37 were conducted to investigate the evolution process of rotating stall in the transonic axial compressor. The development of the shock and the spillage flow and their impacts on the stall process were analyzed minutely. The results show that only one oblique shock was observed in the passage under peak efficiency condition, and the oblique shock evolved into a detached shock under stall condition. The tip leakage vortex broke down after interacting with the detached shock. With the axial development of the broken tip leakage vortex, because of the adverse pressure gradient, a significant vortex was formed in the middle of the passage. At the beginning of the stall process, the spillage flow appeared intermittently under the influence of the periodical evolution of the blockage region. Accompanied by the decrease of the flow rate, the blockage region extended gradually. At the same time, the spillage flow existed during the whole periodical evolution process of the blockage region, which can be treated as the onset of a rapid deterioration of the flow field.