考虑密封环材料属性和表面形貌干气密封启停阶段的动态接触特性分析

Dynamic contact analysis of dry gas seal during start-stop process considering material properties and surface topography of seal rings

干气密封启停阶段的端面接触是不可避免的,为了揭示端面发生接触时的力学特性以保证干气密封稳定运行,运用统计学接触理论和等效阻尼思想,考虑密封环材料属性,推导出适用于分析干气密封干摩擦界面法向动态接触刚度和动态接触阻尼的解析模型,并通过实验测得密封环真实表面形貌,确定了接触模型的初始参数。探究干气密封端面发生接触时动态接触刚度和接触阻尼等参数的变化规律。结果表明,动态接触刚度随接触比压、扰动振幅的增大而增大。扰动频率对动态接触刚度的作用效果远小于接触比压或振幅对接触刚度的作用效果。动态接触阻尼随接触比压的增大而增大,随扰动频率和振幅的增大而减小。通过与多种经典接触模型对比,当前的计算结果与GW模型更为接近。针对干气密封碳化硅作为动环、石墨作为静环的配对方式,在端面未发生磨损时,结合面的微扰动态特性以动态接触刚度为主,动态接触阻尼较弱。法向接触特性的变化主要考虑50%临界脱开转速之前的接触阶段。

The end-face contact during the start-stop process of the dry gas seal is inevitable.In order to reveal themechanical characteristics when the end faces are in contact, the dry gas seal can operate stably. Using statisticalcontact theory and equivalent damping ideas, considering the material properties of the seal ring, an analyticalmodel suitable for analyzing the normal dynamic contact stiffness and dynamic contact damping of the dry frictioninterface of the dry gas seal is derived. The real surface morphology of the seal ring was measured throughexperiments, and the initial parameters of the contact model were determined. The results show that the dynamiccontact stiffness increases with the increase of contact pressure and disturbance amplitude. The effect of disturbance frequency on dynamic contact stiffness is much smaller than contact pressure or amplitude effect.Dynamic contact damping increases with the increase of contact pressure and decreases with disturbance frequencyor amplitude. The current calculation results are closer to the GW model by comparing it with various contactmodels. The sealing rings’ pairing is silicon carbide as the rotating ring and graphite as the stationary ring. Whenthe end face is not worn, the contact surface’s dynamic characteristics are mainly dynamic contact stiffness, and thedynamic contact damping is weak. The change of normal contact is mainly considered in the contact stage before the50% critical detachment speed.