【作者】 李杰；

【导师】 郑铁生；

【作者基本信息】 复旦大学 ， 工程力学， 2009， 硕士

【摘要】 本文探讨气体密封和复杂转子系统的动力学模型及相关算法,着重研究蜂窝密封的动力特性,进而在整个复杂转子系统的框架下进行线性稳定性分析,从中揭示一些规律,对复杂转子系统运动稳定性分析的工程应用具有一定的指导意义。具体地,本文主要的研究内容如下:(1)较为全面地综述了气体密封动力学以及转子动力学两个方面研究的发展历史及研究概况,对有关研究方法进行了较为系统的总结,并分析了各自的适用范围。(2)对于蜂窝密封,由双控制体模型入手,基于摄动分析,进行相关的算法研究。在理论分析中,舍弃转子轴心运动为圆轨迹小扰动的传统假设,而在更符合实际的椭圆轨迹小扰动的前提下,建立蜂窝密封的动力特性分析模型。区别于原来模型及算法繁琐的表达方式,本文采用向量及矩阵形式的表达,形成了更为清晰的模型及更为简洁的算法,得到了与实验结果较为符合的理论计算结果,并且分析了不同的密封参数对动力特性的影响。(3)编制了蜂窝密封的动力特性分析程序,建立了针对复杂转子系统动力学分析的转子—轴承—密封系统动力分析模型并编制了相关动力稳定性分析程序,较为详细地对一个复杂转子系统实例进行了线性稳定性分析。在不同的参数下,针对本文所涉及的蜂窝密封和迷宫密封,分析了其对系统运动稳定性影响。(4)对比分析了蜂窝密封和迷宫密封在四项重要参数下对系统稳定性的影响,揭示了蜂窝密封在高压,大压差,小预旋及小密封间隙这四种情况下,其稳定性表现优于相同参数下的迷宫密封,从而对工程应用具有一定的参考价值。更多还原

【Abstract】 This thesis focuses on a dynamic model of complicated rotor system including honeycomb seals and labyrinth seals and an efficient algorithm involved. With analysis of the dynamic characteristics of the two annular gas seals as a basis, a linear analysis is carried out for the whole rotor system to find some rules about stability of motion, which is helpful for the engineering application.In detail, there are the following contents and achievements in current research.(1) It is summarized that the history and appearance of annular gas seal dynamics and rotor dynamics. Meanwhile, the relevant analytic methods and their applied ranges are also illuminated systematically.(2) With a two-control-volume dimensionless model for honeycomb seal as a basis, relevant algorithm of honeycomb seal are put forward through perturbation analysis. And in the theoretical analysis, the original assumption that the shaft moves in an orbicular track is discarded and this thesis assume that the shaft moves in an elliptical track. And with matrix form, the approach has a clearer model and a more concise algorithm and meanwhile is proved by a comparison between theoretical results and experimental results. Furthermore analysises are made for the influence of different seal parameters on dynamic characteristics.(3) The program for analyzing dynamic characteristics of honeycomb seals is developed as well as the program for analyzing stability of rotor-bearing-seal system with the foundation of the model of rotor-bearing-seal system in this thesis. And through the programs, a detailed linear analysis of stability is carried out for a complicated rotor system equipped with honeycomb seals and labyrinth seals respectively.(4) Contrasts of performances in stability between honeycomb seals and labyrinth seals are demonstrated. We find that honeycomb seals have better performance when stability is considered in the following conditions: smaller pressure gap with same reservoir pressure, bigger pressure gap with same pressure ratio, smaller preswirl and clearance and these rules can be helpful in engineering application.更多还原