迷宫密封非线性气动力研究

发布时间：2018-05-09 02:09

本文选题：迷宫密封 + 双控制体模型　；参考：《复旦大学》2011年硕士论文

【摘要】：迷宫密封是旋转机械中常用的阻止流体泄漏的部件,当密封内转子因挠曲、偏心或旋转发生涡动运动时,密封内流体对转子产生合力,即密封力。密封力对系统稳定性有重要影响,但是由于密封结构以及流体在密封腔内流动状况的复杂性,对于转子-密封系统的气动力研究尚处于初级阶段。本文利用双控制体模型给出了迷宫密封内可压缩流场的控制方程,并与转子振动方程-并无量纲化。针对线性方法求解转子-密封系统无法得到其非线性特性的局限性,提出密封内可压缩流动与转子系统动力学的耦合求解方法,得到了非线性密封力。进而以不平衡转子-密封系统为算例,计算分析了系统的非线性动力特性,得到转子不同转速下的轴心轨迹图和Poincare截面图,可以直观了解系统的非线性动力特性。使用计算流体动力学软件Fluent模拟计算密封腔内可压缩流场,采用标准κ-ε模型来求解迷宫密封的湍流流动,离散方法为有限体积法。网格划分使用四边形网格,并对近壁面网格加密,得到流场速度分布并计算系统动特性参数。
[Abstract]:Labyrinth seal is one of the commonly used parts to prevent fluid leakage in rotating machinery. When the rotor in the seal is whirled because of deflection eccentricity or rotation the fluid in the seal exerts a force on the rotor namely sealing force. The sealing force has an important effect on the stability of the system, but due to the complexity of the sealing structure and the fluid flow in the sealing chamber, the aerodynamic research of the rotor-seal system is still in the primary stage. In this paper, the governing equation of compressible flow field in labyrinth seal is given by using the dual control volume model, and it is dimensionless with the vibration equation of rotor. In order to solve the problem that the nonlinear characteristics of rotor-seal system can not be obtained by linear method, a coupling method between compressible flow in seal and rotor system dynamics is proposed, and the nonlinear sealing force is obtained. Then taking the unbalanced rotor-seal system as an example, the nonlinear dynamic characteristics of the system are calculated and analyzed. The axis trajectory diagram and the Poincare section diagram of the rotor at different rotational speeds are obtained, and the nonlinear dynamic characteristics of the system can be intuitively understood. The compressible flow field in the seal cavity is simulated by the computational fluid dynamics software Fluent, and the turbulent flow in the labyrinth seal is solved by using the standard 魏-蔚 model. The discrete method is the finite volume method. The quadrilateral mesh is used to divide the meshes and the near wall mesh is encrypted to obtain the velocity distribution of the flow field and to calculate the dynamic parameters of the system.
【学位授予单位】：复旦大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH136

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