Effect of Elastic Deformation of the Journal Bearing Shell on its Dynamic Stability

Saber, Esmail M.; Elgamal, Hassan

doi:10.1007/1-4020-4533-6_9

Cited by 3 publications

(3 citation statements)

References 8 publications

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“…Some studies have examined the effect of bearing liner deformation on the slider bearing characteristics (e.g., the pressure distribution, load carrying capacity, and frictional force) [16,17,18,19,20,21,22] and they indicated that the elastic parameter could strongly affect the friction coefficient and the flow rate. Others focused on the impact of the journal eccentricity perturbation or the journal misalignment and the rheological effects of couple stress fluids on stiffness and dynamic coefficients of finite journal bearing with the elastic bearing shell, such as gas foil bearing, offset-halves pressure dam bearing, coupled journal-thrust bearing [23,24,25,26,27,28,29]. Another aspect of the research of elastic bearing properties is that of viscoelasticity.…”

Section: Introductionmentioning

confidence: 99%

Combined Effect of Rarefaction and Effective Viscosity on Micro-Elasto-Aerodynamic Lubrication Performance of Gas Microbearings

Liu

2019

Micromachines

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Elastic deformation and gaseous rarefaction effects are of great importance to the static and dynamic characteristics of gas microbearings. Based on the effective viscosity model of Veijola, the governing equations can be solved by the partial derivative method, finite element procedure, and relaxed iterative algorithm. The numerical results showed that the maximum gas pressure is relatively lower compared to a microbearing with a rigid liner at a local pressure peak region, owing to the film thickness of two converging-diverging profiles and the existence of bimodal pressure inside the elastic microbearing liner. However, the effect of bearing flexibility provides a marginal increase in the load capacity on account of the integral area of pressure distribution is larger than the rigid bearing liner. The friction coefficient and direct stiffness coefficients increase as the elastic modulus decreases while the direct damping coefficients become smaller at high eccentricity ratios and bearing numbers. Since the Poiseuille flow rate increases in connection with an increasing Knudsen number, the effective viscosity of the lubricant leads to a decreased load carrying capacity, friction coefficient, and direct stiffness coefficient, which produces an increase in the direct damping coefficients.

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Section: Introductionmentioning

confidence: 99%

Combined Effect of Rarefaction and Effective Viscosity on Micro-Elasto-Aerodynamic Lubrication Performance of Gas Microbearings

Liu

2019

Micromachines

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“…Sharma et al (2002) and Rajasekhar and Sharma (2011) analyzed the effect of oil cavity shape on the static and dynamic performance of hydrostatic bearings. Saber and El-Gamal (2006) studied the impact of the elastic deformation of the sliding bearing on its dynamic stability. Ettles et al (2016) optimized the design of large thrust bearings.…”

Section: Introductionmentioning

confidence: 99%

The dynamic simulation and experiment of bearing capacity of multi oil cushion static bearing with double rectangular cavities

Zhang

Sun

Kong

et al. 2019

ILT

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Purpose The purpose of the paper is to analyze the bearing capacity of hydrostatic bearing during the change of film thickness under different working conditions and to improve the processing efficiency and precision of equipment. Design/methodology/approach In this study, Q1-205 double rectangular cavity hydrostatic thrust bearing is selected as the research object. The dynamic mesh method and ANSYS/FLUENT software are used to simulate the curves of oil film thickness and oil pressure under different operating conditions. Finally, the change of pressure in the oil cavity at different operating speeds under a certain inlet flow rate was tested through design experiments. Findings When the film thickness was thick, the maximum pressure in the oil cavity at different inlet velocities showed little difference. With a larger inlet flow, the maximum pressure in the oil cavity was higher. The pressure at the edge of the oil seal was linearly distributed. The oil pressure in the downstream side was greater than that in the counter flow side. When the working pressure was low, the pressure in the oil cavity slightly decreased with the increase of working speed. Moreover, the pressure loss at high speed was considerable. Originality/value Based on the lubrication theory, the mathematical model of the bearing oil film was set up. The bearing capacity equation of the hydrostatic cavity was derived. The double-rectangular-annular hydrostatic guides studied in this paper have not been reported in previous research literature and the method of dynamic mesh dynamic simulation of variable viscosity is seldom studied before. The bearing characteristics and the change of oil film thickness under different working conditions have been studied systematically and comprehensively. The theoretical analysis results are basically consistent with the experimental results.

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“…For the elasto-hydrodynamic lubrication line-point contact problem, Habchi et al [2] solved the Reynolds equation using a full-system approach, fully coupling the hydrodynamic lubrication and bearing's elastic deformation. The stability of a plain cylindrical journal bearing having an elastic shell was studied by Saber and El-Gamal [3] using a perturbed Reynolds equation and a simple threedimensional elasticity model which neglected the tangential strain of the shell. Kim and Andres [4] coupled the Reynolds equation for a thin gas film and a simple elastic foundation model to predict the performance of heavily loaded gas foil bearings.…”

Section: Introductionmentioning

confidence: 99%

Application of Computational Fluid Dynamics and Fluid–Structure Interaction Method to the Lubrication Study of a Rotor–Bearing System

et al. 2010

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Computational methods were used to analyse the elasto-hydrodynamic lubrication of a complex rotorbearing system. The methodology employed computational fluid dynamics (CFD), based on the Navier-Stokes equation and a fluid-structure interaction (FSI) technique. A series of models representing the system were built using the CFD-FSI methodology to investigate the interaction between the lubrication of the fluid film, and elastic dynamics of the rotor and journal bearing. All models followed an assumption of isothermal behaviour. The FSI methodology was implemented by setting nodal forces and displacements to equilibrium at the fluid-structure interface, therefore allowing the lubrication of the fluid and the elastic deformation of structures to be solved simultaneously. This is significantly different to the more common techniques-such as the Reynolds equation method-that use an iterative solution to balance the imposed load and the force resulting from the pressure of the fluid film to within a set tolerance. Predictions using the CFD-FSI method were compared with the results of an experimental study and the predictions from an 'in-house' lubrication code based on the Reynolds equation. The dynamic response of the system was investigated with both rigid and flexible bodies for a range of different bearing materials and dynamic unbalanced loads. Cavitation within the fluid film was represented in the CFD-FSI method using a simplified phase change boundary condition. This allowed the transition between the liquid and vapour phases to be derived from the lubricant's properties as a function of pressure. The combination of CFD and FSI was shown to be a useful tool for the investigation of the hydrodynamic and elasto-hydrodynamic lubrications of a rotor-bearing system. The elastic deformation of the bearing and dynamic unbalanced loading of the rotor had significant effects on the position of its locus.

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Effect of Elastic Deformation of the Journal Bearing Shell on its Dynamic Stability

Cited by 3 publications

References 8 publications

Combined Effect of Rarefaction and Effective Viscosity on Micro-Elasto-Aerodynamic Lubrication Performance of Gas Microbearings

Combined Effect of Rarefaction and Effective Viscosity on Micro-Elasto-Aerodynamic Lubrication Performance of Gas Microbearings

The dynamic simulation and experiment of bearing capacity of multi oil cushion static bearing with double rectangular cavities

Application of Computational Fluid Dynamics and Fluid–Structure Interaction Method to the Lubrication Study of a Rotor–Bearing System

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