Transient analysis for offset-elliptical journal bearings under misalignment and dynamic loading

Abstract

Although the offset-elliptical journal bearings (OEJBs) are widely used in industry, there are few researches on the OEJBs, especially under the conditions of journal misalignment and sudden load. To overcome such deficiency, the dynamic response of misaligned OEJBs subjected to the dynamic load has been studied in this paper. Based on the Reynolds equation, Euler equation, and kinetic equations, a hydrodynamic model is developed and validated to conduct the transient analysis for the OEJBs. Moreover, the modified film thickness of the misaligned OEJB is given. The partial derivative method and the finite difference method are adopted to solve the lubrication equations. The correlations of bearing characteristics such as the minimum film thickness, maximum film pressure, journal orbits, and time-varying dynamic coefficients with the misalignment and dynamic load are studied. In addition, the effects of the misalignment, rotating speed, and clearance ratio on the transient performance of OEJBs under the dynamic load are discussed in detail. The results indicate that the journal misalignment and dynamic load have a significant impact on the transient performance of OEJBs. The decrease of the film thickness caused by the journal misalignment can be aggravated by the suddenly applied load. The proposed model can provide theoretical fundament in the design and monitoring of the dynamically loaded bearing-rotor system.

Transient tribo-dynamic performance of journal bearings considering wear behavior during start-up

“…7 To understand and predict the transient tribological dynamics behavior of a tribo-pair, a theoretical model is required. [8][9][10][11][12][13] As a result, numerical models for simulating the dynamic behavior of journal bearing start-up processes have gained popularity in recent years. [14][15][16][17] In recent years, the numerical prediction of bearings during start-up has become increasingly sophisticated.…”

“…7 To understand and predict the transient tribological dynamics behavior of a tribo-pair, a theoretical model is required. 8–13 As a result, numerical models for simulating the dynamic behavior of journal bearing start-up processes have gained popularity in recent years. 14–17…”

Manufacturing error and misalignment effect on the transient lubrication behavior of dynamically loaded journal bearing with micro-groove

“…Subsequently, Gu et al [28] developed a numerical model with misalignment and texture to analyze the axial trajectory and energy loss of bearings under time-varying dynamic load conditions. Wang et al [29] systematically studied the transient behavior of offset-elliptical bearing and found that the effect of misalignment on the minimum film thickness under dynamic load conditions is significant. Xiong et al [30] explored the impact of misalignment and viscoelastic deformation on the performance parameters and found that the coupling effects are more accurate under time-varying dynamic loads.…”