退化涡轮叶片形变对气动参数偏离的影响研究

Research on the Influence of the Deformation of Degraded Turbine Blades on the Deviation of Aerodynamic Parameters

涡轮叶片在服役过程中发生的形状变化会造成涡轮气动参数偏离,研究造成涡轮性能退化的主要形变因素是实现涡轮精准维护的重要环节。本文分析了实际涡轮叶片在长时间服役后的具体形变特征,以及形变特征与气动参数偏离值的关系;通过光学扫描获得退化涡轮全周叶片的形状数据,重构得到叶片特征几何参数;以几何参数为基础生成退化的涡轮流道,通过CFD仿真得到了燃气轮机在退化前后的详细气动参数;采用神经网络模型建立涡轮几何数据与气动数据之间的映射关系,并分析了模型中影响气动参数偏离的主要几何参数。结果表明:磨损烧蚀导致弦长变短是第1级静叶气动参数变化的主要诱因,而第1级动叶的气动参数则主要受喉道宽度的影响。

The in-service deformation of the turbine blade will cause the deviation of the turbine aerodynamic parameters.Exploring the main deformation factors that cause turbine performance degradation is an important part of accurate turbine maintenance.The specific deformation characteristics of real turbine blades after long-term service and the relationship between the turbine blade deformation characteristics and the deviation of aerodynamic parameters are analyzed.The geometric data of the circumferential blades of degraded gas turbine are obtained through optical scanning, and the characteristic geometric parameters of the blades are reconstructed.The degraded turbine flow passage is generated based on the geometric parameters, and the detailed aerodynamic parameters of the gas turbine before and after degradation are obtained through CFD simulation.The mapping relation between turbine geometric data and aerodynamic data is established by neural network model, and the main geometric parameters that affect the deviation of aerodynamic parameters in the model are analyzed.The results show that the shortening of chord length caused by wear and thermal erosion is the main cause of the aerodynamic parameters variation of the first-stage stator vane, while the aerodynamic parameters of the first-stage rotor blade are mainly affected by the width of the throat.