【作者】 李娜；

【导师】 鲍文博；

【作者基本信息】 沈阳工业大学 ， 固体力学， 2008， 硕士

【摘要】 微型燃气轮机发电机是近年来发展的新型发电系统,具有可靠性高、可遥控、自诊断等特殊优势,受到航空航天和军事等方面的广泛关注。国家对发展微型燃气轮机发电机相当重视,已把微型燃气轮机发电机作为重点科研攻关项目,但与欧美国家相比,我国在微型燃气轮机发电机的研究和应用方面还有很大的差距。本文针对微型燃气轮机磁悬浮轴承-转子系统的耦合和非线性动力学特性进行了研究,为微型燃气轮机发电机结构设计提供理论依据。本文首先介绍了磁悬浮转子系统的组成、工作原理以及其差动控制系统的基本原理;采用二元Taylor级数对电磁力进行了简化,建立五自由度的磁悬浮转子系统的动力学模型。其次分析了磁悬浮转子系统中径向轴承内的力耦合及径向轴承之间的力耦合、力矩耦合现象,研究了各种耦合力沿磁力轴承圆周的分布情况、变化规律及耦合力与系统结构参数之间的关系,并考虑各种耦合因素的影响,建立其耦合动力学模型,通过数值方法对简化的转子动力学模型和考虑耦合力的转子动力学模型进行对比分析。分析结果表明系统是稳定的,考虑耦合后系统的固有频率变大,且前两阶固有频率相对变化较大,同时固有频率随耦合力的增大而增大,耦合力对前两阶频率的影响较大,对第三阶频率的影响较小;最后分析磁悬浮轴承-转子系统非线性动态特性,主要考虑电磁力的非线性项作用,建立了刚性磁浮轴承转子系统动力学模型和空间状态方程,用数值积分法对其稳定性进行了研究。通过数值分析得到了系统在某些参数域中的波形图、相图、轴心轨迹,直观显示了系统在这些参数域中的运行性态。同时将非线性影响因素和耦合影响因素综合考虑进去,建立更为准确的动力学模型。本文的研究表明:微型燃气轮机—高速发电机磁悬浮轴承转子系统的耦合因素对系统动力学特性有一定的影响;同时转子在一定偏心量下,以60000r/min转速的运转是稳定的。本文的研究为更好控制磁浮轴承转子系统运行状态提供了理论参考。更多还原

【Abstract】 The micro gas turbine (MGT) is a developing power generation system in recent years. With advantage of high reliability, remote-control, self-diagnosis, it is widely given attention to in aerospace and military fields. Our country puts a high premium on the development of MGT and takes it as important projects. Comparing with America and European countries, our country has a large disparity in the fields of research and application of MGT. In this paper, coupling and nonlinear dynamic characteristics of micro gas turbine bearing-rotor system have been studied. It provided theoretic evidence for the structural design of MGT.At first, the structure and working principle of magnetic suspended rotor system and basic principle of the differential drive control system have been explained in the paper. The electric magnetic force of the system is simplified by adopting two dimensions Taylor progression. Then kinetic models of 5-DOF magnetic suspended spindle system were set up.Secondly the coupling force in radial magnetic bearing of magnetic suspended spindle system and the moment coupling between the front and the rear radial magnetic bearings were analyzed. The distribution and variation of coupling forces along magnetic bearing circle were analyzed. The relations between coupling forces and structure parameters were studied. Considering the influence of coupling forces the coupling kinetic models were established. The simplified kinetic model of the rotor and kinetic model under coupling forces were studied. Then the numerical results were given between coupling and uncoupling models.Analytical result indicates that the system is steady. The natural frequencies were bigger when coupling influence was considered. The first two natural frequencies vary a lot, at the same time natural frequencies increase when coupling forces increased. The coupling forces have a bigger effect on the first two natural frequencies than the third natural frequency. At last, nonlinear dynamic characteristics of magnetic suspended bearing-rotor system are analyzed when nonlinear terms of magnetic force were considered. The kinetic model of rigid magnetic suspended bearing-rotor system and state-space equation were established. Then the stability of magnetic suspended bearing-rotor system was studied in numeric analysis approach. Through numerical analysis the wave-shape figures, phase figures and tracks of the crankshaft figures in some parameter regions were yielded. These figures demonstrated the systemic movement state was steady in these parameter regions. At the same time nonlinear influence factors and coupling influence factors were considered synchronously, and then the more exact kinetic model was established.The analysis in the paper indicates that the coupling factors of micro gas turbine magnetic suspended bearing-rotor system have some effects on dynamic characteristics of the system. At the same time, the rotor can keep on rotating steadily with the rotate speed of 60000r/min under definite eccentricity. The study of this paper provides theoretical reference for controlling the movement state of magnetic suspended rotor system.更多还原