汽轮机轴承动力特性三维流固耦合分析模型

THREE DIMENSIONAL FLUID-SOILD COUPLED ANALYTICAL MODELOF STEAM TURBINE BEARING

为了研究汽轮机转子-轴承系统非线性动力特性,从三维流体方程出发,建立了考虑轴承与转子之间耦合作用的有限元分析模型。分析指出轴承流场由轴颈旋转和振动决定:当轴颈位置固定时,流场是转速和振动的线性函数;线性函数的系数是轴颈位置的非线性函数;文中进一步对转子-轴承系统动力特性进行了分析。指出油膜压力振荡幅值随轴颈振幅的增大而非线性增大。应用该模型比较好地模拟了两种不同情况下油膜失稳故障的发生与发展过程。

In order to analyze rotor-bearing system nonlinear dynamics, a new model considering fluid-solid coupling effect is set up from three-dimensional incompressible viscous flow equations using Galerkin FEM theory. Bearing flow field is decided by the joint effects of rotor eccentric rotation and vibration. It is the linear function of rotating speed and vibration if journal position is fixed. The coefficients of linear functions are nonlinear functions of journal position. Detailed simulation is done for a rotor bearing system. Oil film force oscillating amplitude increases sharply with rotor vibration amplitude. The start and development process of oil instability fault is simulated successfully using the model.