涡轮级燃气入侵的理论分析及数值模拟

A Theoretical and Numerical Study of Turbine Rim Seal Ingestion

为了分析航空发动机涡轮级中的燃气入侵现象,提出一种研究封严间隙处流动规律的理论方法,并采用全环模型进行了数值模拟。在该理论方法中,动盘旋转、封严冷气、外环主流对流动的影响用三个特征速度来表征;它们的相互作用用速度比来描述。数值模拟结果表明:随着速度比的变化,封严间隙处呈现燃气沿静盘入侵、燃气基本不入侵以及燃气沿动盘入侵等三种流动形式。利用速度比的影响规律,可初步判断封严间隙处的燃气入侵情况以及最小封严冷气流量。

To study the ingestion in the turbine stage of aero engine,a theoretical method concerning the flow pattern at rim seal clearance was raised, followed by numerical simulations employing a 360° model. Ac?cording to this theoretical method,the effects of rotor,cooling flow and main flow can be characterized by three characteristic velocities and their interactions can be featured with velocity ratios. The simulation results show that as the velocity ratios change,the flow pattern at the rim seal clearance varies from ingestion along the stator to non-ingestion and ingestion along the rotor. Through vast simulations,rules have been extracted,which can be used to assess the ingestion level and determine the minimum cooling flow initially.