An Analysis of Grease and Oil Lubricated Spiral Grooved Bearings

1974 ◽  
Vol 96 (2) ◽  
pp. 275-283
Author(s):  
D. M. Dewar
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Three Dimensional ◽  
Thermal Conditions ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Through Flow ◽  
Load Carrying ◽  
Running Torque ◽  
Spiral Groove Bearing

Mathematical models for grease and oils are put forward and used to solve a two-dimensional Reynolds’ equation with a quasi three-dimensional energy equation for any geometry of spiral groove bearing. Using numerical methods, results are presented for the temperature distributions in through-flow and block-centered thrust bearings; conical bearings and herringbone grooved journal bearings can also be dealt with. The overall bearing parameters, namely, load-carrying capacity, stiffness, and running torque at various eccentricity ratios are shown along with their dependence upon the prevailing thermal conditions.

scholarly journals Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 44
Author(s):  
Christian Ziese ◽  
Cornelius Irmscher ◽  
Steffen Nitzschke ◽  
Christian Daniel ◽  
Elmar Woschke
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Reliable Prediction ◽  
Two Phase ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Run Up ◽  
The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

Geometry Optimization of Textured Three-Dimensional Micro- Thrust Bearings

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
C. I. Papadopoulos ◽  
E. E. Efstathiou ◽  
P. G. Nikolakopoulos ◽  
L. Kaiktsis
Keyword(s):  
Carrying Capacity ◽  
Stokes Equations ◽  
Load Capacity ◽  
Three Dimensional ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Micro Channels ◽  
Wide Range ◽  
Load Carrying ◽  
Bearing Load

This paper presents an optimization study of the geometry of three-dimensional micro-thrust bearings in a wide range of convergence ratios. The optimization goal is the maximization of the bearing load carrying capacity. The bearings are modeled as micro-channels, consisting of a smooth moving wall (rotor), and a stationary wall (stator) with partial periodic rectangular texturing. The flow field is calculated from the numerical solution of the Navier-Stokes equations for incompressible isothermal flow; processing of the results yields the bearing load capacity and friction coefficient. The geometry of the textured channel is defined parametrically for several width-to-length ratios. Optimal texturing geometries are obtained by utilizing an optimization tool based on genetic algorithms, which is coupled to the CFD code. Here, the design variables define the bearing geometry and convergence ratio. To minimize the computational cost, a multi-objective approach is proposed, consisting in the simultaneous maximization of the load carrying capacity and minimization of the bearing convergence ratio. The optimal solutions, identified based on the concept of Pareto dominance, are equivalent to those of single-objective optimization problems for different convergence ratio values. The present results demonstrate that the characteristics of the optimal texturing patterns depend strongly on both the convergence ratio and the width-to-length ratio. Further, the optimal load carrying capacity increases at increasing convergence ratio, up to an optimal value, identified by the optimization procedure. Finally, proper surface texturing provides substantial load carrying capacity even for parallel or slightly diverging bearings. Based on the present results, we propose simple formulas for the design of textured micro-thrust bearings.

Effect of Nanoparticle Additives on Journal Bearing Lubricated with Non-Newtonian Carreau Fluid

2015 ◽  
Vol 751 ◽  
pp. 137-142 ◽  
Author(s):  
W. Gunnuang ◽  
C. Aiumpornsin ◽  
Mongkol Mongkolwongrojn
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Journal Bearing ◽  
Research Work ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Carreau Fluid ◽  
Load Carrying ◽  
Nanoparticle Additives

This research work presents the influence of Al2O3 nanoparticle additives on the performance characteristics of a journal bearing. Non-Newtonian fluid based on Carreau viscosity model was represented for SAE10W50 oil blended with Al2O3 nanoparticles in this work. Reynolds equation and energy equation have been formulated and solved numerically using finite difference method and multigrid multilevel techniques with boundary conditions. The static characteristics of the journal bearing under isothermal and adiabatic conditions were examined. The results show that the addition of Al2O3 nanoparticles improve load-carrying capacity of the journal but almost no change on film temperature due to good thermal property of Al2O3 nanoparticles.

Analysis of a Hydrodynamic Thrust Bearing With Incomplete Film

1981 ◽  
Vol 103 (3) ◽  
pp. 355-359 ◽  
Author(s):  
I. Etsion ◽  
I. Barkon
Keyword(s):  
Reynolds Equation ◽  
Iterative Solution ◽  
Flow Equation ◽  
Load Carrying Capacity ◽  
Free Boundaries ◽  
Thrust Bearings ◽  
Lubricating Film ◽  
Load Carrying ◽  
Bearing Load ◽  
Wetted Area

The possibility of an incomplete lubricating film due to directed lubrication in hydrodynamic thrust bearings is considered. The free boundaries of the wetted area on a flat sector-shaped pad are determined by a simultaneous iterative solution of the Reynolds equation and a flow equation. Bearing load carrying capacity and power loss are calculated for a variety of inlet geometries, and a comparison is made with a complete fluid film bearing. It is found that bearing performance can be very much affected by the radial location of lubricant supply to the pads.

Pavement Damage Due to Conventional and New Generation of Wide-Base Super Single Tires

2005 ◽  
Vol 33 (4) ◽  
pp. 210-226 ◽  
Author(s):  
I. L. Al-Qadi ◽  
M. A. Elseifi ◽  
P. J. Yoo ◽  
I. Janajreh
Keyword(s):  
Carrying Capacity ◽  
Material Properties ◽  
Three Dimensional ◽  
Fe Analysis ◽  
Load Carrying Capacity ◽  
Inflation Pressure ◽  
3D Finite Element ◽  
Load Carrying ◽  
Pavement Damage ◽  
New Generation

Abstract The objective of this study was to quantify pavement damage due to a conventional (385/65R22.5) and a new generation of wide-base (445/50R22.5) tires using three-dimensional (3D) finite element (FE) analysis. The investigated new generation of wide-base tires has wider treads and greater load-carrying capacity than the conventional wide-base tire. In addition, the contact patch is less sensitive to loading and is especially designed to operate at 690kPa inflation pressure at 121km/hr speed for full load of 151kN tandem axle. The developed FE models simulated the tread sizes and applicable contact pressure for each tread and utilized laboratory-measured pavement material properties. In addition, the models were calibrated and properly validated using field-measured stresses and strains. Comparison was established between the two wide-base tire types and the dual-tire assembly. Results indicated that the 445/50R22.5 wide-base tire would cause more fatigue damage, approximately the same rutting damage and less surface-initiated top-down cracking than the conventional dual-tire assembly. On the other hand, the conventional 385/65R22.5 wide-base tire, which was introduced more than two decades ago, caused the most damage.

Computational Fluid Dynamics Thermohydrodynamic Analysis of Three-Dimensional Sector-Pad Thrust Bearings With Rectangular Dimples

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
C. I. Papadopoulos ◽  
L. Kaiktsis ◽  
M. Fillon
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Carrying Capacity ◽  
Thermal Effects ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
Performance Indices ◽  
Thrust Bearings ◽  
Load Carrying ◽  
Texture Design

The paper presents a detailed computational study of flow patterns and performance indices in a dimpled parallel thrust bearing. The bearing consists of eight pads; the stator surface of each pad is partially textured with rectangular dimples, aiming at maximizing the load carrying capacity. The bearing tribological performance is characterized by means of computational fluid dynamics (CFD) simulations, based on the numerical solution of the Navier–Stokes and energy equations for incompressible flow. Realistic boundary conditions are implemented. The effects of operating conditions and texture design are studied for the case of isothermal flow. First, for a reference texture pattern, the effects of varying operating conditions, in particular minimum film thickness (thrust load), rotational speed and feeding oil pressure are investigated. Next, the effects of varying texture geometry characteristics, in particular texture zone circumferential/radial extent, dimple depth, and texture density on the bearing performance indices (load carrying capacity, friction torque, and friction coefficient) are studied, for a representative operating point. For the reference texture design, the effects of varying operating conditions are further investigated, by also taking into account thermal effects. In particular, adiabatic conditions and conjugate heat transfer at the bearing pad are considered. The results of the present study indicate that parallel thrust bearings textured by proper rectangular dimples are characterized by substantial load carrying capacity levels. Thermal effects may significantly reduce load capacity, especially in the range of high speeds and high loads. Based on the present results, favorable texture designs can be assessed.

The Validity of the Reynolds Equation in Modeling Hydrostatic Effects in Gas Lubricated Textured Parallel Surfaces

2005 ◽  
Vol 128 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Y. Feldman ◽  
Y. Kligerman ◽  
I. Etsion ◽  
S. Haber
Keyword(s):  
Carrying Capacity ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Physical Parameters ◽  
Load Carrying Capacity ◽  
Wide Range ◽  
Load Carrying ◽  
Parallel Surfaces

Microdimples generated by laser surface texturing (LST) can be used to enhance performance in hydrostatic gas-lubricated tribological components with parallel surfaces. The pressure distribution and load carrying capacity for a single three-dimensional dimple, representing the LST, were obtained via two different methods of analysis: a numerical solution of the exact full Navier-Stokes equations, and an approximate solution of the much simpler Reynolds equation. Comparison between the two solution methods illustrates that, despite potential large differences in local pressures, the differences in load carrying capacity, for realistic geometrical and physical parameters, are small. Even at large clearances of 5% of the dimple diameter and pressure ratios of 2.5 the error in the load carrying capacity is only about 15%. Thus, for a wide range of practical clearances and pressures, the simpler, approximate Reynolds equation can safely be applied to yield reasonable predictions for the load carrying capacity of dimpled surfaces.

Density Variation Effects in Stepped-Thrust Bearings

1959 ◽  
Vol 26 (3) ◽  
pp. 337-340
Author(s):  
C. F. Kettleborough
Keyword(s):  
Coefficient Of Friction ◽  
Carrying Capacity ◽  
Thrust Bearing ◽  
Density Variation ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Load Carrying ◽  
The Coefficient Of Friction

Abstract The problem of the stepped-thrust bearing is considered but, whereas normally volumetric continuity is assumed, the equations are solved assuming mass continuity; i.e., the variation of density is also considered as well as the effect of the stepped discontinuity on the load-carrying capacity and the coefficient of friction. Computed theoretical curves illustrate the importance of the density on the operation of this bearing and, in part, explain results already published.

Finite Element Analysis of the Static Performance of a Self-Slot-Compensating Aerostatic Bearing

2011 ◽  
Vol 199-200 ◽  
pp. 749-753
Author(s):  
Xiao Bo Zuo ◽  
Jian Min Wang ◽  
Chao Liang Guan ◽  
Juan Li
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Geometric Parameters ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Aerostatic Bearing ◽  
Element Analysis ◽  
Consistent Condition ◽  
Load Carrying ◽  
Static Performance

The static performance of an aerostatic bearing with angled surface self-slot-compensation is analyzed. The consistent condition was applied to unitize the Reynolds equation of different forms and the finite element method (FEM) was used to solve the equation. The load carrying capacity (LCC) and the stiffness of the bearing was obtained and the influence of the geometric parameters was discussed. It is concluded that this self-compensating aerostatic bearing can achieve a good performance; the geometric parameters of the gap are interactive, and should be rationally matched.

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