多场耦合转子系统的动力学建模与特性分析

Power industry plays an important role in the development of the national economy. With the increasing of single-machine capacity of the generator set, the operation stability of the rotor system faces more challenges. In view of the multi-field coupling in thermal power unit and hydroelectric unit, the lateral-torsional coupling dynamic model of the rotor system is established, in which, the influences of flow, thermal and electromagnetic field are included. In this project, four problems are investigated in detail: 1, the influence of the eccentric on the fluid loading acting on the turbine; 2, the added mass and moment of inertia and the damping of the fluid around the turbine; 3, the thermal effect on the rotor system caused by the unsymmetric cooling; 4, the influence of power network on the vibration of the rotor system. Combining theoretical analysis, numerical simulation and experimental study, the operation stability of the rotor system and the dynamic response with the common excitations are analyzed. Based on these studies, the systemic and general dynamic modeling method for rotor system with multi-field coupling is presented, and the analysis method of operation stability and the calculation method of dynamic response for high dimensional nonlinear rotor system are developed. The influences of fluid, thermal and electric parameters on the vibrations of the rotor system are studied, and the conclusions are helpful to realize the safe operation of the generator set and accelerate the development of power industry in our country.

电力工业在国民经济发展中扮演着十分重要的角色。随着发电机组单机容量的逐步增大，机组轴系振动引起的运行稳定性问题变得日益突出。本项目针对火电机组和水电机组轴系多场耦合的特点，重点分析涡轮偏心对流体载荷的影响，涡轮处流体附加质量、转动惯量和阻尼，冷却气体流量周向不均匀导致的转子热效应，电网对机组轴系振动的影响，建立综合考虑流场，温度场和电磁场影响的轴系弯扭耦合转子动力学模型。综合运用理论分析、数值仿真和实验研究，分析转子系统的运行稳定性和典型激励下转子的动力学响应。提出多场耦合条件下，系统、通用的转子动力学建模方法，并发展高维、非线性转子系统的全局稳定性分析方法和动力学响应计算方法。获得流体、热和电磁参数对轴系振动的影响规律。为大型发电机组的安全、稳定运行提供理论依据和技术保障，推动我国电力工业的进一步发展。

汽轮机、航空发动机、燃气轮机等大型旋转机械常常运行在流-固-热多场耦合的复杂环境中，为了更准确地分析其动力学特性，为装备设计及安全稳定运行提供理论依据，需要研究多场耦合对系统动力学特性的影响。在流固耦合振动方面，以航空发动机转子系统为背景，建立了带封严蓖齿鼓筒的三维流场通道模型，计算了转静子同心和不同偏心量条件下鼓筒表面静压以及蓖齿封严诱导的气流激振力，分析了气动载荷作用下鼓筒的动力学特性，得到了蓖齿封严转子的气动载荷边界条件。在热影响方面，建立了有效分析轴向非均匀温度场中超静定转子的热作用力模型，提出了引入可叠加的点热源模型来描述任意轴向位置的径向非均匀温度场、推导温度梯度导致的热弯矩并进而得到转轴热振动解析解的方法。对于电磁力的作用，建立了空间磁场中旋转机械电磁耦合振动普适动力学模型，探究了偏心气隙、铁磁感应与电磁场耦合作用机理，得到了旋转机械系统电磁耦合振动的时域、频域及稳定性特征，揭示了电磁场对旋转机械系统动力学行为的作用规律。