Non-Linear Dynamics of a Rotor-Bearing-Seal System

Abstract

The non-linear dynamic behaviors of a rotor-bearing-seal coupled system are investigated by using Muszynska's non-linear seal fluid dynamic force model and non-linear oil film force, and the result from the numerical analysis is in agreement with the one from the experiment. The bifurcation of the coupled system is analyzed under different operating conditions. It is indicated that the dynamic behavior of the rotor-bearingseal system depends on the rotation speed, seal clearance and seal pressure of the rotor-bearing-seal system. The system state trajectory, Poincaré maps, frequency spectra and bifurcation diagrams are constructed to analyze the dynamic behavior of the rotor center. Various non-linear phenomena in the coupled system, such as periodic motion and quasi-periodic motion are investigated. The results show that the system has the potential for chaotic motion. The study may contribute to a further understanding of the non-linear dynamics of such a rotor-bearing-seal coupled system.

A nonlinear model of flow-structure interaction between steam leakage through labyrinth seal and the whirling rotor

“…(12,13) and linearized variables into Eq. (7) and neglecting the terms of order 2 ε and the higher, the first-order continuity equation for the ith cavity is reduced as…”

“…The above-mentioned linear model was reduced from a preconditioned track of the whirling rotor, which slightly deviates from the statically balanced position; otherwise, the nonlinear behaviors of the whirling rotor, e.g., lock-on frequency and kick amplitude, could not be accurately captured by the linearized force-displacement model [2][3][4][9][10][11]. Hua et al [12] and Cheng et al [13] carried out nonlinear analysis of the rotordynamics associated with leakage air flow through a simple annular seal by using the Muzynska model [14]. The authors [15] delineated the nonlinear behavior of the whirling rotor subjected to the leakage air flow through the labyrinth seal by using both perturbation analysis and Muzynska model.…”

Order reduction and nonlinear behaviors of a continuous rotor system

“…Several possible complex motions including periodic, double-periodic, quasi-periodic motions were revealed. Considering the variations of a series of factors, rotating speed, seal clearance and seal pressure, Cheng et al [10] investigated the vibration of rotor/bearing/seal coupled system, and some complicated behaviors including multi-periodic motion, quasi-periodic motion and chaos were also found. The stability of a rotor/bearing/seal system was also studied by Shen and Zhao [11] using both numerical simulation and experiment, which shows that the theoretical results are in good agreement with the experimental ones.…”

Active Rotor Vibration Control

“…The following formulas are very often used (Cheng et al 2006, Ding et al 2002, Li et al 2003, Li et al 2007) for approximation of stiffness K, damping D and circumferential average velocity ratio λ as functions of the relative radial eccentricity: …”

“…A rotor dynamics and a rotor vibration are extensively studied in present publications (Adams 2010, Dimarogonas et al 2013, Gash et al 2006, Muszyńska 2005, Kiciński 2002, Kowal 1996, especially in technical papers (Cheng et al 2006, Ding et al 2002, Gosiewski, Górmiński 2006, Li et al 2003, Li et al 2007, Muszyńska, Bently 1989, Tuma et al 2007. But there are significantly fewer publications dealing with an active vibration control of the rigid rotor housed in journal bearings (Tuma et al 2013, Vitecek et al 2008, Vitecek et al 2010.…”