摘要
为了研究压气机带间隙平面叶栅近失速工况下叶尖涡系结构特点以及其非定常流动特性,本文采用大涡模拟(Large eddy simulation,LES)方法对典型叶栅进行数值计算并结合Q准则分析叶尖涡系结构特点,探索流动规律及叶尖涡系耦合过程。研究表明:与额定工况相比,近失速工况叶尖流场更为复杂,并通过大涡模拟观察到了次泄漏涡的存在;额定工况下泄漏涡不发生破碎,主次泄漏涡在近失速条件下均发生破碎,破碎后形成的低能流体与尾缘分离涡是造成叶尖堵塞及损失的主要原因;次泄漏涡在不同时刻生成点位置及与弦长夹角周期性变化,次泄漏涡的摆动与叶尖角区分离涡团的周期性脱落是叶尖非定常性的主要原因。
To investigate the structure and the unsteady flow characteristics of the tip vortices under near stall condition of a compressor cascade with clearance, the large eddy simulation (LED) method is con- ducted with NACA64-A905 cascade to explore the structure characteristics, the flow pattern and the coupling process of the tip vortices with Q criteria. It is found that compared with the rated condition, the tip flow field in the near stall condition is more complicated. The existence of secondary tip leakage vortex is found by LES. Tip leakage vortex does not breakup under the rated condition while the main and the secondary tip leakage vortex will breakup in the near stall condition, and the low-energy fluid caused by the breakup of tip leakage vortices and the trailing separation vortex are the main causes of tip blocking and loss. The secondary tip leakage vortex's forming point and the angle with chord are period- ically changed in different time, and this together with the periodic shedding of corner separation vortex are the main reasons of the unsteady tip flow.
出处
《南京航空航天大学学报》
EI
CAS
CSCD
北大核心
2017年第5期676-683,共8页
Journal of Nanjing University of Aeronautics & Astronautics
关键词
航空发动机
扩压叶栅
大涡模拟
非定常流动
泄漏涡
aeroengine
compressor cascades
large eddy simulation
unsteady
1ow
tip leakage vortex