航空发动机旋转叶片-涂层机匣碰摩机理及动力学特性研究

Aiming at the rubbing between rotor blade and coating casing in aeroengine, on the basis of rotor dynamics, contact dynamics, nonlinear vibration and friction theory, a rubbing presentation model considering the elastic effects of the coating and casing is established by combing principle of work power with the wear mechanism of the coating. By considering the change of the blade tip clearance, the dynamic model of the blade and coating casing coupling system is established and dynamic simulation is carried out by using the semi-analytical method and numerical integration method. The simulation model is verified and revised by experiment. The rubbing mechanism is studied and the intrinsic mechanism of mutual coupling and interaction among the blade vibration, rubbing and coating wear is revealed. The excitation power of the parameters on the low and high order vibrations is evaluated, and the mapping relation among the local features of rubbing force, friction states, the degree of the wear and the vibration response of the blade is revealed. The key parameters influencing rubbing intensity and the blade vibration are seeked and effective methods for adjusting and restraining the rubbing are explored. The results can provide theoretical basis for the physical design of the rotor blade and casing with coating , and the technical support for predicting and controlling dynamic performance of the system.

针对航空发动机转子叶片与带涂层机匣间的碰摩问题，以转子动力学、接触动力学、非线性振动和摩擦学等理论为基础，考虑涂层和机匣的弹性影响，基于功能原理并结合涂层磨损机理，建立叶片-涂层机匣碰摩表征模型；考虑涂层磨损导致的叶尖间隙变化，建立叶片-涂层机匣耦合系统动力学模型，利用半解析和数值积分法进行碰摩动力学仿真，通过实验进行模型验证与修订。研究叶片与涂层机匣之间的碰摩机理，探索叶片振动、碰摩和涂层磨损三者之间相互影响、相互制约的内在机制；分析参数对叶片低阶和高阶振动的激发能力，揭示碰摩力、摩擦状态、磨损程度等局部碰摩特征和叶片振动响应之间的映射关系；力争找到影响碰摩、涂层磨损和叶片振动的关键参数，进而探索抑制碰摩的有效方法。研究结果可为航空发动机转子叶片、涂层机匣的结构设计提供理论依据，也可为预测和控制系统的动态性能提供技术支持。

航空发动机碰摩主要出现在叶片和机匣以及鼓筒和静子叶片之间，其中叶片-机匣间的碰摩更为危险。这是因为叶片尖端处有更高的线速度，碰摩能量大，对叶片振动的影响也大。叶片-机匣间的碰摩涉及更加复杂的冲击过程，主要体现在：碰撞发生在柔性体与柔性体间，碰撞力将主要取决于碰撞柔性体本身的整体变形，而非局部变形；由于叶尖与线速度方向有一定的夹角，叶片碰撞为斜碰撞，容易诱发叶片的弯扭耦合变形；叶片在碰摩过程中，自身位置有明显的移动，所以冲击不能看成是瞬时的；考虑叶片碰摩过程中对涂层的影响，会导致变间隙，且涂层磨损对叶片的动力学特性也会产生一定的影响。对于叶片-未涂层机匣和叶片-机匣碰摩的激振机理以及涂层磨损机理，目前已成为重要的研究热点之一。考虑机匣的柔性及弹性支承影响，本项目将机匣简化为集中质量点和柔性环，推导了两个叶片-机匣法向碰摩力表征模型，并通过模型试验验证了模型的有效性；将叶片简化为悬臂梁、悬臂板、变厚度壳、盘片，分析了叶片-机匣碰摩机理；在上面研究基础上考虑转子涡动的影响，建立了转子-叶片-机匣及转子-盘片-机匣动力学模型，分析了碰摩对叶片、机匣和转子振动响应的影响规律，并通过模型试验部分验证了仿真结果的有效性。研究结果揭示了碰摩激发的高阶振动诱发的叶片掉角故障机理，对转子叶片-机匣间隙选择及叶片、机匣结构设计具有一定的参考意义。