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.

CFD Thermohydrodynamic Analysis of 3-D Sector-Pad Thrust Bearings With Rectangular Dimples

2013 ◽  
Author(s):  
C. I. Papadopoulos ◽  
L. Kaiktsis ◽  
M. Fillon
Keyword(s):  
Carrying Capacity ◽  
Thermal Effects ◽  
Computational Study ◽  
Load Capacity ◽  
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.

Thermal and Inertia Effects in Turulent-Flow Thrust Bearings

1980 ◽  
Vol 22 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Z. S. Safar
Keyword(s):  
Carrying Capacity ◽  
Thermal Effects ◽  
Analytical Study ◽  
Load Carrying Capacity ◽  
Inertia Effects ◽  
Thrust Bearings ◽  
Load Carrying ◽  
Laminar And Turbulent Flow ◽  
Energy Equations ◽  
Inertia Forces

This paper presents a semi-analytical study of the influence of inertia terms on the thermohydrodynamic analysis of infinitely-wide thrust bearings operating under conditions of laminar and turbulent flow. The momentum and energy equations are not seriously affected by the presence of inertia forces. Results show that the inclusion of inertia terms causes an increase in the fluid film pressure and load-carrying capacity. Thermal effects exert a pronounced influence on bearing performance.

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.

Static and dynamic performance characteristics of powder lubricated symmetrical three-lobed bearing

2020 ◽  
pp. 135065012092632
Author(s):  
Jijo Jose ◽  
Niranjana Behera
Keyword(s):  
Carrying Capacity ◽  
Elevated Temperatures ◽  
Dynamic Performance ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
Oil Degradation ◽  
Static And Dynamic Characteristics ◽  
Load Carrying ◽  
The Coefficient Of Friction ◽  
Ellipticity Ratio

Hydrodynamic oil bearings applied at elevated temperatures and extreme operating conditions are subjected to the problem of oil degradation. In order to overcome such conditions, dry powder lubricants are used as lubricants in the hydrodynamic journal bearings. Thus the problem of thermal degradation of oil at high temperatures can be eliminated. In this work, the static and dynamic characteristics of a symmetric three-lobed bearing lubricated with powdered particles have been predicted. Influence of the ellipticity ratio on the performance of the three-lobed bearing has also been investigated. It is observed that an increase in the ellipticity ratio increases the coefficient of friction and stability, but decreases the side leakage and the load carrying capacity of the three-lobed bearing. Also, it was observed that the large-sized powdered particles induce better load carrying capacity and better stability than the small-sized particles.

The limiting load-carrying capacity of foil thrust bearings

2017 ◽  
Vol 232 (8) ◽  
pp. 1046-1052
Author(s):  
P Samanta ◽  
MM Khonsari
Keyword(s):  
Analytical Solution ◽  
Carrying Capacity ◽  
Simple Procedure ◽  
Load Carrying Capacity ◽  
Thrust Bearings ◽  
Limiting Load ◽  
Load Carrying ◽  
Closed Form Analytical Solution ◽  
Foil Thrust Bearing ◽  
Thrust Load

A simple procedure is proposed for predicting the limiting pressure and corresponding limiting of the load-carrying capacity of a foil thrust bearing. A closed-form analytical solution for the limiting load is derived, and the predictions are verified by the numerical solution. An approximate solution for limiting thrust load is also obtained and compared to the value obtained through the analytical solution. A parametric analysis is performed to examine the dependency of the limiting load on different geometric parameters for the bearing.

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.

Theoretical and Experimental Analysis of Hydrostatic Thrust Bearings

1960 ◽  
Vol 82 (3) ◽  
pp. 505-511 ◽  
Author(s):  
R. C. Elwell ◽  
B. Sternlicht
Keyword(s):  
Experimental Verification ◽  
Carrying Capacity ◽  
Experimental Analysis ◽  
Load Carrying Capacity ◽  
Constant Flow ◽  
Temperature Changes ◽  
Thrust Bearings ◽  
Flow Restriction ◽  
Load Carrying ◽  
Different Types

This paper presents theoretical and experimental analysis of two types of circular hydrostatic thrust bearings, using incompressible lubricants. Design equations for load-carrying capacity, stiffness, and flow, are given for three different types of flow restriction—orifice, capillary, and constant flow. Experimental verification of the equations is shown. It is seen that each method of restriction imparts its own characteristics on the bearing performance. Constant flow, for instance, results in the stiffest bearing under certain conditions, and capillary restriction is unaffected by temperature changes.

Flow Parameters in Hydrostatic Lubrication for Several Bearing Shapes

1960 ◽  
Vol 82 (2) ◽  
pp. 257-264 ◽  
Author(s):  
S. Raynor ◽  
A. Charnes
Keyword(s):  
Conformal Mapping ◽  
Film Thickness ◽  
Flow Rate ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Total Load ◽  
Thrust Bearings ◽  
Flow Parameters ◽  
Load Carrying ◽  
Mapping Techniques

In the case of hydrostatic lubrication the designer of thrust bearings has to make decisions regarding the shape of pads, location of oil holes, and configuration of oil grooves. In this paper several pad shapes and associated oil inlets were investigated using conformal mapping techniques to obtain the total load-carrying capacity, flow rate of oil, oil-film thickness, pressure and velocity distribution. The results of these calculations permit the designer to approximate his chosen configuration by computed models in order to estimate the flow parameters.

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