Theoretical Studies of a Continuously Adjustable Hydrodynamic Fluid Film Bearing

2001 ◽  
Vol 124 (1) ◽  
pp. 203-211 ◽  
Author(s):  
J. K. Martin ◽  
D. W. Parkins
Keyword(s):  
Film Thickness ◽  
Reynolds Equation ◽  
Solution Procedure ◽  
Fluid Film ◽  
Theoretical Studies ◽  
Analysis Model ◽  
Operating Characteristics ◽  
Hydrodynamic Bearing ◽  
Wide Range ◽  
Fluid Film Thickness

Principles of a continuously adjustable hydrodynamic bearing are described together with an analysis model for studying its theoretical performance. The model included an expanded form of the governing Reynolds equation which took account of non-uniform variations in the fluid film thickness. A solution procedure was devised whereby for a given set of adjustment conditions, simultaneously converged fields of fluid film thickness, temperature, viscosity and pressure would result, together with oil film forces. A wide range of operating characteristics were studied with results predicting advantages and benefits over conventional hydrodynamic bearings.

Performance Analysis of a Nonrecessed Hybrid Conical Journal Bearing Compensated With Capillary Restrictors

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Prashant G. Khakse ◽  
Vikas M. Phalle ◽  
S. S. Mantha
Keyword(s):  
Performance Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Parameter ◽  
Radial Load ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Fluid Film Thickness ◽  
Film Stiffness

The present paper deals with the performance analysis of a nonrecessed hole-entry hydrostatic/hybrid conical journal bearing with capillary restrictors. Finite element method has been used for solving the modified Reynolds equation governing the flow of lubricant in the clearance space of journal and bearing. The hole-entry hybrid conical journal bearing performance characteristics have been depicted for a wide range of radial load parameter (W¯r  = 0.25–1.5) with uniform distribution of holes at an angle of 30 deg in the circumferential direction. The numerically simulated results have been presented in terms of maximum fluid film pressure, minimum fluid film thickness, lubricant flow rate, direct fluid film stiffness coefficients, direct fluid film damping coefficients, and stability threshold speed. However, the proposed investigation of nonrecess hole-entry hybrid conical journal bearing shows important performance for bearing stiffness and minimum fluid film thickness at variable radial load and at given operating speed.

Surface Roughness Effects on Fluid Flow between Two Rotating Cylinders

2015 ◽  
Vol 642 ◽  
pp. 275-280
Author(s):  
Sutthinan Srirattayawong ◽  
Shian Gao
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Reynolds Equation ◽  
Surface Profile ◽  
Fluid Film ◽  
Real Surface ◽  
Contact Center ◽  
Roughness Effects ◽  
Fluid Film Thickness ◽  
Lubricant Viscosity

In general, the thin fluid film problems are explained by the classical Reynolds equation, but this approach has some limitations. To overcome them, the method of Computational Fluid Dynamics (CFD) is used in this study, as an alternative to solving the Reynolds equation. The characteristics of the two cylinders contact with real surface roughness are investigated. The CFD model has been used to simulate the behavior of the fluid flows at the conjunction between two different radius cylinders. The non-Newtonian fluid is employed to calculate the lubricant viscosity, and the thermal effect is also considered in the evaluation of the lubricant properties. The pressure distributions, the fluid film thickness and the temperature distributions are investigated. The obtained results show clearly the significance of the surface roughness on the lubricant flow at the contact center area. The fluctuated flow also affects the pressure distribution, the temperature and the lubricant viscosity in a similar pattern to the rough surface profile. The surface roughness effect will decrease when the film thickness is increased.

Analysis of a Worn Multirecess Hydrostatic Journal Bearing System

2009 ◽  
Author(s):  
E. Vijaya Kumar ◽  
Vikas M. Phalle ◽  
Satish C. Sharma ◽  
S. C. Jain
Keyword(s):  
Reynolds Equation ◽  
Journal Bearing ◽  
Flow Equation ◽  
Fluid Film ◽  
Wear Depth ◽  
Lubricant Flow ◽  
Wide Range ◽  
Fluid Film Thickness ◽  
Range Of Values ◽  
Bearing System

In recent times Hydrostatic journal bearings have received considerable amount of attention by the researchers on account of their excellent performance as compared to other class of bearings. The objective of the present paper is to presents an analysis of a four-pocket capillary-compensated worn hydrostatic journal bearing system. The FEM has been used to solve the Reynolds equation governing the flow of lubricant in the clearance space of a multirecess journal bearing system together with capillary restrictor flow equation as a constant. The bearing performance characteristics of a capillary compensated 4-pocket worn hydrostatic journal bearing have been presented for a wide range of values of external load and nondimensional wear depth parameters. The numerically simulated results of bearing characteristics parameters in terms of maximum fluid-film pressure, minimum fluid-film thickness, lubricant flow rate and fluid film reaction have been presented. The simulated results suggest that for an accurate prediction of bearing characteristics data it is essential to include the effect of wear in the analysis of the hydrostatic journal bearing system.

Vibration of Plate Structures Solved by DQEM Using EDQ

2003 ◽  
Author(s):  
Chang-New Chen
Keyword(s):  
Numerical Algorithms ◽  
Element Model ◽  
Equation System ◽  
Solution Procedure ◽  
Analysis Model ◽  
Engineering Structures ◽  
Discrete Eigenvalue ◽  
Plate Structures ◽  
Wide Range ◽  
Structural Boundary

The vibration of plate structures is solved by DQEM using EDQ. In the DQEM discretization, EDQ is used to define the discrete element model. Discrete eigenvalue equations defined at interior discrete points in all elements, transition conditions defined on the inter-element boundary of two adjacent elements and boundary conditions at the structural boundary form the overall discrete eigenvalue equation system. Numerical results obtained by the developed numerical algorithms are presented. They demonstrate the developed numerical solution procedure. This vibration analysis model can be used to solve wide range of offshore engineering structures.

Reynolds Equation for Spherical Bearings

2002 ◽  
Vol 125 (1) ◽  
pp. 203-206 ◽  
Author(s):  
Donna Meyer
Keyword(s):  
Film Thickness ◽  
Reynolds Equation ◽  
Variable Viscosity ◽  
Horizontal Position ◽  
Hemispherical Shell ◽  
Pressure Distributions ◽  
Spherical Bearing ◽  
Classical Paper ◽  
Fluid Film Thickness ◽  
Generalized Reynolds Equation

Osborne Reynolds’ classical paper on the theory of lubrication Reynolds (1886) produced the generalized Reynolds equation. For spherical bearing applications, the generalized Reynolds equation is transformed in order to obtain useful results when the hemispherical shell is not in a horizontal position. A new film thickness expression is also presented. These transformations permit the determination of pressure distributions and fluid film thickness for any orientation of the hemispherical shell including the horizontal position, for which the conventional description of Reynolds equation is well suited. The resulting equation in two-dimensional form, for an incompressible, variable viscosity fluid, with upper and lower sliding surfaces, in spherical coordinates, contains the inclination angle β, which accounts for non-horizontal positions of the shell.

Rheological Behaviors of Pressure-Driven Radial Flow

2007 ◽  
Author(s):  
Z. Xie ◽  
Q. Zou ◽  
D. Yao
Keyword(s):  
Film Thickness ◽  
Radial Flow ◽  
Practical Interest ◽  
Fluid Film ◽  
Fluid Viscosity ◽  
Surface Shear Stress ◽  
Surface Shear ◽  
Shear Dependent Viscosity ◽  
Fluid Film Thickness ◽  
Pressure Driven

The characteristics of fluid flows confined within microscale space are of theoretical and practical interest [1]. Such flow includes the thin lubrication films, the liquid flow between biological cells, and the flow of polymer melts in a micro-injection molding machines, etc. A pressure-driven radial flow microrheometry (PDRFM) is used to characterize high-shear microscale fluids. The shear-dependent viscosity of the pressure-driven radial flow is modeled to investigate the possible size effect on the fluid viscosity. In the modeling, the surface shear rate and surface shear stress at the edge of the radial flow are expressed in terms of three measurable parameters, i.e. the flow rate, the loading force, and the fluid film thickness. By decreasing the fluid film thickness to microscale level, this model can be used to study the microscale effect of any homogeneous fluids. The analysis has been verified by using CFD simulations as digital testing platforms. Furthermore, the preliminary experimental results of Newtonian and non-Newtonian flows also proved the rheological modeling.

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