Nonlinear dynamic behaviors of a rotor-labyrinth seal system

Abstract

The nonlinear model of rotor-labyrinth seal system is established using Muszynska's nonlinear seal forces. We deal with dynamic behaviors of the unbalanced rotor-seal system with sliding bearing based on the adopted model and Newmark integration method. The influence of the labyrinth seal on the nonlinear characteristics of the rotor system is analyzed by the bifurcation diagrams and Poincare' maps. Various phenomena in the rotor-seal system, such as periodic motion, double-periodic motion, quasi-periodic motion and Hopf bifurcation are investigated and the stability is judged by Floquet theory and bifurcation theorem. The influence of parameters on the critical instability speed of the rotor-seal system is also included.Nomenclature c d radial clearance of seal l length of seal

Rotordynamic analysis of systems with a non-linear model of tilting pad bearings including turbulence effects

“…The mathematical equations of the horizontal rotor is a modified version of the one developed by Krämer [20], and it is similar to the model used by Li et al [21]. These equations for the rotor and journals are:…”

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.…”

Rotor‐systems with compliant seals: A comparison of the rotordynamics using the Muszynska model and Hirs' lubrication equations

“…Here, m f is the coefficient of the fluid inertia, D 0 is the coefficient of the fluid damping, K 0 is the coefficient of the fluid radial stiffness, Ω is the angular speed of the rotor, τ 0 is the fluid average circumferential speed ratio and n and b are empirical parameters [5]. The parameters m f , D 0 and K 0 are fitted for the present case using Childs analytic formulas [6].…”