A Review of Journal Bearing Thermal Effects on Rotordynamic Response

Abstract

Traditional analysis of journal bearings assumed a constant viscosity which simplified the solutions for static and dynamic characteristics and responses. Today's high-performance machinery requires more accurate models wherein temperature and viscosity distributions in the film must be calculated. Thermal effects in journal bearings have a strong influence on both static and dynamic properties, and consequently play a critical role in determining rotor-bearing system performance. This paper presents an extensive survey of the thermal modeling methods and effects in journal bearings. The subjects include various bearing types, and recent progress in thermal bearing design and thermal instability problems observed in fluid and gas film hydrodynamic bearings. The extent of the survey ranges from conventional Reynolds equation models to more advanced CFD models.

Dynamic of a Flexible Rotor-Bearing System Supported by Worn Tilting Journal Bearings Experiencing Rub-Impact

“…Furthermore, Jin et al [15] investigated the pivot stiffness effect on the vibration amplitude of TPJBs and showed that pivot stiffness leads to reduce the resonance and working amplitude of the system. Finally, Shin et al [16] published a review paper on thermal modeling methods for journal-bearing systems. They did not mention any previous works which simulated the effect of temperature-induced variations of the oil film viscosity on the dynamic behavior of a rotor-worn TPJB.…”

Łożyska Hydrodynamiczne Promieniowe Oraz Nieliniowe Zjawiska Drgań W Łożyskach Z Panewkami Wahliwymi

“…Some twenty years later, Brown et al [8] found that the rotating unbalance could induce chaotic vibration. Other nonlinear phenomena have connections with thermal effects [9] and friction or contact forces in self-equalising bearings [3]. Non-uniform shear stress in the oil film can heat the journal surface due to hydrodynamic friction.…”

“…If only a small part of the surface is heated repeatedly, a shaft bends, changing the unbalance distribution. This thermal instability is called the Morton effect [9]. Various bearing designs can suppress mentioned instabilities or undesirable rotor behaviour and effects.…”

A novel transient computational fluid dynamics-fluid–structure interaction model for the pad adaptive motion and rotordynamic coefficients of hybrid porous tilting pad bearings

“…Computational fluid dynamics (CFD) has emerged as a significant approach for investigating the performance of journal bearings by directly solving flow equations without employing additional simplifications. For fixed journal bearings, Shin et al 14 conducted an extensive survey ranging from conventional Reynolds equation models to more advanced CFD models. For porous-type journal bearings, Balasoiu et al 15 conducted a 3D isothermal CFD analysis of a cylindrical porous journal bearing with a self-circulating lubricating system.…”