指尖密封/转子系统密封力的一种计算方法

A Method of Calculating Seal Force of Finger Seal/Rotor System

指尖密封作为转子系统中组成部件,其与转子之间的相互力学作用对系统动态特性会产生影响。从系统的观点研究提出指尖密封密封力的计算方法,是构建和开展转子系统动力学模型和相关动力学分析的基础工作。本文首先通过流固耦合分析实现了嵌入指尖密封结构效应的指尖密封气膜刚度与气膜阻尼计算,构建了指尖密封气膜刚度和气膜阻尼拟合公式,在此基础上结合指尖密封-转子的接触处理,建立指尖密封/转子相互作用力学模型,提出了一种适用于转子系统动态分析的指尖密封密封力的计算方法,并通过算例实施了指尖密封密封力计算流程,同时探讨了密封力与密封工况条件的关系。计算结果表明:指尖密封气膜刚度随密封压力差增大而增大,转子转速对气膜刚度的影响很小;指尖密封气膜阻尼随密封压力差和转子转速的增大而减小。接触区的密封力随转子涡动幅值增大而增大,但基本不随转子转速变化,非接触区的密封力随转子涡动幅值的增大而减小,随着转子转速增大而增大。指尖密封的密封力随时间呈周期性变化,密封力变化频率随转子转频增加而增加。

The finger seal as the component of a rotor system and the mechanical interaction between the finger seal and the rotor affect the dynamic characteristics of the system.Therefore we propose the seal force calculation method to build the rotor system′s dynamics model and analyze its related dynamics.In this paper,the gas film stiffness and gas film damping of the finger seal are realized by means of solid-fluid coupling analysis,and the related fitting formulas are established.Then,the mechanical model of finger seal/rotor interaction is established by combining finger seal/rotor contact processes;a method of calculating the seal force which is applied to the dynamic analysis of the rotor system is proposed.The calculation process of seal force is also implemented by an example and the relationship between seal force and working conditions is discussed.The results show preliminarily that:The gas film stiffness of the finger seal increases with the increase of fluid pressure,and the rotor speed has little influence on the film stiffness;the gas film damping of finger seal decreases with the increase of fluid pressure and rotor speed.The seal force in contact region increases with the rotor′s whirl amplitude but basically does not change with the rotor speed;the seal force in the non-contact region decreases with the increase of the rotor′s whirl amplitude and increases with the rotor speed.The seal force varies periodically with time,and the frequency of sealing force increases with the increase of rotor frequency.