Research into the dynamic coefficient of the rotor-seal system for teeth-on-stator and teeth-on-rotor based on an improved nonlinear seal force model

Abstract

It is well known that seal force has a great influence on dynamic coefficients of the rotor-seal system and Muszynska's model is employed by many scholars to research the seal system. But the rotor-seal system has larger eccentricity ratio, Muszynska's model will not describe the characteristics of the rotor-seal system well. So a more accurate model is critical for describing the seal force. An improved nonlinear model of a rotor-seal system is proposed for describing seal force of the rotor-seal system based on the two-control-volume model and rotor motion equation. This model can not only solve the larger eccentric problem but can also bring a simple calculation through the numerical methods. Dynamic coefficients of the rotor-seal system are also researched based on the new nonlinear model under the condition of the toothon-stator and tooth-on-rotor. In order to verify that the equation-control model is correct, Childs and Scharrer's experiment and two-control-volume model are employed and there is a comparison between theoretical results and experimental results. The result shows that theoretical results from the improved model are in better agreement with Childs and Scharrer's experiment than two-control-volume model. The proposed model in this paper provides a theoretic reference for further research on the rotor-seal system.

Transient CFD Simulation on Dynamic Characteristics of Annular Seal under Large Eccentricities and Disturbances

“…These empirical parameters obtained by employing the CFD analysis are used in the subsequent nonlinear analysis, regardless of whether the whirl amplitude is around the concentric position or not. He and Jing [20] indicated that Muszynska's model will not describe the dynamic characteristics of the rotor-seal system well when the rotor-seal system has larger eccentricity ratio. However, the present paper is devoted to develop nonlinear dynamic models of concentric seal with large whirl amplitude or eccentric seal with large static eccentricity and rather small whirl amplitude.…”