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

Abstract

Annular seals of turbomachinery usually suffer from various degrees of eccentricities and disturbances due to the rotor–stator misalignment and radial loads, while the discussion of annular seal under both large static eccentricities and dynamic disturbances is relatively limited. In this paper, the applicability of linear assumption and reliability of nonlinear dynamic model for eccentric annular seals under large eccentricities and disturbances is discussed based on the investigation of seals with various rotor motions through computational fluid dynamics (CFD). After the validation of transient CFD methods by comparison with experimental and bulk theory results, the dynamic behaviors of annular seal are analyzed by adopting both direct transient simulations and the nonlinear Muszynska model. The results show that the nonlinear dynamic model based on rotor circular whirls around seal center can predict the fluid excitations of different types of rotor motions well under small static eccentricities, while it is limited severely with large static eccentricities, which indicates that the dynamic characteristics of annular seal under large eccentricities are related with the rotor’s motion ways. The paper provides a reference for studies of rotor–seal system with complex rotor motions considering radial loads or running across the resonance region.

The lip motion trajectory of eccentric oil seal considering material viscoelasticity

“…Pinedo et al (2014Pinedo et al ( , 2017, established numerical methods to calculate the magnitude of interference and contact forces of the oil seal lip when under the eccentric state, shedding light on the interrelation between interference and contact forces and the angle of shaft rotation. Zhang et al (2020) used CFD method to study the dynamic characteristics of the seal under large eccentricity, it indicates that there is radial motion of the seal under eccentric conditions, which affects the operational performance of the seal. Building upon the eccentric radial reciprocating motion of the oil seal under eccentric conditions, Borras et al (2020) analyzed the variation in pumping rate under eccentric conditions based on its macroscopic wedgeshaped structure.…”

Nonlinear Analysis of Rotor-Bearing-Seal System with Varying Parameters Muszynska Model Based on CFD and RBF

“…Xu [14] conducted research into the stability of rotor/seal systems with dynamic vibration absorbers. The dynamic characteristics of annular seals under large eccentricities were investigated by the transient CFD simulation [15]. The surrogate model was applied to the parametric design of a rotor-seal system by Mutra [16].…”