叶根失速先兆触发跨声速压气机失速的机制研究

Mechanism Study of Stall Triggered by Hub Region Inception in a Transonic Compressor

关键词:  跨声速压气机  高负荷  叶根失速先兆  旋转失速  失速机制

Key words:  Transonic compressor  High load  Hub region inception  Rotating stall  Stall mechanism

摘要:

实验中发现了一种起始于叶根的新型压气机失速先兆，为了探索这种先兆的初始扰动特征及失速的动态发展机制，对该压气机开展全周非定常数值研究。数值结果表明，在压气机进入失速的过程中，静子叶根区域首先形成堵塞区，验证了失速初始扰动起源于叶根区域。该扰动由六个轴对称分布、以45%转子转速旋转的堵塞团组成。随着失速程度的加深，静子叶根堵塞团在低叶高范围内合并为整圈的分离区，造成整个叶根区域流动的堵塞。叶根的堵塞导致气流从堵塞区上方绕行，加快了叶尖区域的流动速度，激波的增强导致叶顶泄漏涡破碎程度加剧，形成转子叶尖堵塞区并发展为旋转失速团，最终导致压气机失速。

Abstract:

A new type of stall inception starting from the hub region was found in the experiments. Full-annulus transient simulations were carried out to explore the characteristics of the initial disturbance and the dynamic development mechanism of the stall process. The simulation results show that the blockage area firstly forms in the stator hub region during the stall process， indicating that the disturbance initiates in the compressor hub region. The disturbance is consisted of six axisymmetric blockages which are rotating at 45% of the rotor speed. In the stall evolution， the blockages merge into a full-annulus separation zone， leading to more serious flow blockage at low blade height. Because of the hub region blockage， more fluid have to go through the tip region， resulting in the increase of tip region flow rate， so the tip region fluid is accelerated. Moreover， shock wave/tip leakage vortex interaction cause the formation of tip blockage. The tip region’s blockage finally develops into rotating stall cells which lead to the compressor eventual stall.