叶轮机械密封及转子相互作用研究

发布时间：2018-04-13 17:33

本文选题：指尖密封 + 流固耦合　；参考：《哈尔滨工程大学》2013年博士论文

【摘要】：对于叶轮机械而言，转动部件与静止部件之间不可避免地会出现工质的泄漏，这部分没有经过主流的工质对做功是没有贡献的。因此需要利用转子密封对其进行封严以降低其泄漏、减少功率损失。优良的转子密封所带来的性能改善，已经切实地体现在叶轮机械效率提高、运行和维修成本降低等方面。随着转子运转速度(发电用叶轮机械除外)与负载的日益提高，转子与密封之间的相互作用越发强烈。如若转子与密封之间的匹配不当，轻则增加泄漏、降低整机效率，重则可损伤转子或导致密封件破碎进入主流，造成更为严重的伤害。本文正是在这样的背景下提出了对转子与密封之间的相互作用展开研究，，并对转子振动规律的计算以及流固耦合的方法进行了深入的探讨。本论文主要在两个方面展开研究工作：基于双向流固耦合的方法对指尖密封及其改进结构进行数值分析获得了指尖密封的泄漏以及动力学特性；从转子动力学计算出发研究密封所对应转子的运动规律，并将转子运动引入到环形转子密封的流场分析中，得出了转子运动与转子密封之间的相互影响规律。总的来说，本文中针对上述问题所进行的具体研究内容包括： 1.深入并系统地分析指尖密封的变形与流动特征。 (1)采用已有的指尖密封结构并对其进行适当的改进，通过理论及数值分析，得到了不同的指尖密封结构在泄漏流体作用下的变形特性；设计了升力垫开槽的特殊结构并对其进行数值模拟，获得了开槽结构在升力及流场方面的特征，证实了开槽结构对指尖密封性能的提升所做的贡献。 (2)建立了考虑密封片之间摩擦力作用的整周指尖密封计算模型，通过数值计算获得了指尖密封的变形及流场规律，并进一步得出了开槽结构在指尖密封性能提升方面的作用；将数值计算结果与成型的试验数据进行对比，找出了数值模拟可以与试验结果相匹配的工况范围。研究表明升力垫上的开槽结构可显著改善指尖密封的升力特性，这对于通过简单的结构改型来提高指尖密封的性能或降低其固有缺陷提供了依据。理论与数值分析获得的指尖密封变形及泄漏特征对于指尖密封的结构设计具有一定的参考价值。 2.对密封转子动力学以及转子与迷宫、蜂窝密封之间的相互作用展开研究。 (1)应用基于转子动力学的方法编写求解转子振动特性参数的程序，获得振幅与振频这两个能够描述转子振动规律的参数。 (2)将转子振动参数引入到转子密封的流场非稳态计算中，获得迷宫和蜂窝密封在转子振动条件下的动态特性，分析振动引起的不平衡气体力对转子的影响。 (3)对比不同结构迷宫及蜂窝密封在泄漏特性上的差异，并从流动的根源上出发分析产生差异的原因。研究说明了转子振动对密封泄漏量的影响，并且阐述了迷宫和蜂窝密封所产生的转子气体力是有可能对转子减振做出贡献的；并且从转子气体作用力的角度分析了蜂窝密封在减振降噪方面的优势。
[Abstract]:For the impeller, between rotating and stationary components will inevitably leak refrigerant, the refrigerant has not been the mainstream on work there is no contribution. So we need to use the seal on the rotor seal to reduce the leakage, reduce the power loss. Excellent sealing performance improvement brought by the rotor. Have to reflect the improvement in efficiency of turbomachinery, operation and maintenance costs.
As the rotor speed (generating turbomachinery except) and load increasing, the interaction between the rotor and the seal is very strong. If improper between the rotor and the seal, light leakage increase, reducing the overall efficiency, weight can damage or cause the rotor seal breaking into the mainstream, causing more serious harm. This article is in this context by the research on the interaction between the rotor and the seal, and the calculation of the rotor vibration rule and method of fluid solid coupling is discussed.
This paper focuses on the research work in two aspects: the two-way flow solid coupling method based on finger seal and improved structure obtained by numerical analysis of finger seal leakage and dynamics; calculating the motion law of the corresponding research on sealing rotor based on rotor dynamics, and flow field analysis of rotor movement into the rotor seal ring that, the interaction regularity between the rotor movement and rotor seal. In general, the research content of this paper is to solve the problem mentioned above are included:
1. the deformation and flow characteristics of the fingertip seal are analyzed in depth and systematically.
(1) the use of the existing structure of the finger seal and appropriate for its improvement, through theoretical and numerical analysis, obtained the different finger seal structure in the leakage and deformation characteristics under the influence of fluid; the design of the special structure of the lift pad slotted and numerical simulation on the characteristics obtained in the lift and flow slot structure the confirmed slotted structure on the sealing performance of fingertip lifting made contribution.
(2) the establishment of the seal model considering the friction between the sealing piece the whole week fingertips, obtained by numerical calculation of deformation and flow field characteristics of finger seal, and further that the slotted structure in the role of finger seal performance; the numerical results and the experimental data were compared to find out the forming, numerical simulation can be match the test result and the operating range.
The research shows that the lift pad can be slotted structure significantly improve the lift characteristics of finger seal, which improve the performance of finger seal or reduce the inherent defects of provides the basis for the modification of the structure. Through simple theoretical and numerical analysis of the deformation and leakage characteristics of finger seal has a certain reference value for the structural design of finger seal.
2. the dynamics of the sealed rotor and the interaction between the rotor and the labyrinth and the honeycomb seal are studied.
(1) based on rotor dynamics, a program for solving rotor vibration characteristic parameters is compiled to obtain two parameters that can describe rotor vibration.
(2) the rotor vibration parameters are introduced into the unsteady flow field calculation of rotor seal, and the dynamic characteristics of labyrinth and honeycomb seals under rotor vibration condition are obtained, and the influence of unbalanced gas force caused by vibration on rotor is analyzed.
(3) the differences in the leakage characteristics of the labyrinth and honeycomb seals of different structures are compared, and the reasons for the difference are analyzed from the origin of the flow.
Study shows that the effect of vibration on rotor seal leakage, rotor gas force and describes the labyrinth and honeycomb seals generated is likely to contribute to the rotor vibration; and the rotor from the gas force analysis of honeycomb seal in vibration damping and noise reduction advantage.

【学位授予单位】：哈尔滨工程大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TH136

【参考文献】