考虑主动间隙控制的涡轮叶尖间隙建模计算研究

Research on Turbine Tip Clearance Modeling Considering

关键词:  发动机  涡轮叶尖间隙  实时模型  多项式拟合  主动间隙控制

Key words:  Engine  Turbine tip clearance  Real-time model  Polynomial fitting  Active clearance control

摘要:

建立了具有涡轮叶尖间隙计算功能的发动机实时模型并设计了主动间隙控制系统，以反映涡轮叶尖间隙控制对发动机动、静态性能的影响。提出以半无限平面瞬态热传导与多项式拟合相结合的方法，更准确计算发动机动态过程中变化的叶尖间隙；基于涡轮叶尖间隙的变化量和涡轮性能参数的关系实时修正当前涡轮性能参数，提高了常规发动机部件级模型的计算准确度，且涡轮叶尖间隙每减少0.25mm，涡轮效率提高1%，耗油率下降1%；在分析气冷式主动间隙控制系统的基础上，设计了一种可以控制叶尖间隙变化的机械式主动间隙控制系统，使动态过程中变化的叶尖间隙始终处于指令间隙。通过对发动机地面加速过渡过程和巡航减速过渡过程的仿真，验证了上述方案的有效性。

Abstract:

In order to reflect effects of static and dynamic performance with the changes of turbine tip clearance，a real-time engine component level model with the function of turbine tip clearance calculation and active clearance control system were studied. A method to estimate the related temperature and calculate dynamic tip clearance more accurately was presented which is a combination of semi-infinite transient heat conduction equations and polynomial fitting. Through the relationship between the change of turbine tip clearance and performance parameters，current turbine performance map were corrected to improve the calculation accuracy of conventional engine component level model. A 0.25 mm reduction in turbine tip clearance can lead to an increase in turbine efficiency up to 1% and a reduction in sfc by 1%. Compared with the active tip control systems of air-cooled，a mechanical active tip clearance control system with clearance change in the closed-loop was demonstrated to make the dynamic process tip clearance always in the required position. The simulation results during the transition process of ground acceleration and cruise deceleration verified the effectiveness of the new real-time engine model and active clearance control system.