The Performance of Hydrodynamic Lubricating Films With Viscosity Variations Perpendicular to the Direction of Motion

1972 ◽  
Vol 94 (1) ◽  
pp. 44-48 ◽  
Author(s):  
E. B. Qvale ◽  
F. R. Wiltshire
Keyword(s):  
Film Thickness ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
End Effects ◽  
Parametric Curves ◽  
One Dimensional ◽  
Lubricating Film ◽  
Families Of Curves ◽  
Load Carrying ◽  
The Coefficient Of Friction

The effects of prescribed viscosity variations across a hydrodynamic lubricating film are studied. The film is strictly one dimensional and end effects are neglected. The viscosity variations are given by three families of curves. The considerable decreases (in the limit 100 percent) and occasional increases in the coefficient of friction that can occur for constant film thickness and load-carrying capacity are evaluated and the results are presented in terms of parametric curves. Important physical situations where these viscosity variations may be observed or produced are described.

A Demonstrably Optimum One Dimensional Journal Bearing

1972 ◽  
Vol 94 (2) ◽  
pp. 188-192 ◽  
Author(s):  
S. M. Rohde
Keyword(s):  
Film Thickness ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Infinite Length ◽  
Load Carrying Capacity ◽  
One Dimensional ◽  
Load Carrying ◽  
Minimum Film Thickness ◽  
Constant Viscosity ◽  
Nonlocal Formulation

By the use of a new variational technique, the bearing profile which maximizes the load carrying capacity of an infinite length journal bearing is obtained. The lubricant is assumed to be incompressible and of constant viscosity. The flow is assumed to be laminar and the optimization is based upon a minimum film thickness. The solution obtained is a concentric step bearing with a film thickness ratio of 1.812 and a ridge to pad ratio of 0.328. It is mathematically shown by the use of the “nonlocal” formulation that this step profile does yield a maximum among all profiles sufficiently “close.”

Measurement of Load-Carrying Capacity of Thin Lubricating Films

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Xia Li ◽  
Feng Guo ◽  
Shuyan Yang ◽  
P. L. Wong
Keyword(s):  
Film Thickness ◽  
Carrying Capacity ◽  
Constant Load ◽  
Experimental Results ◽  
Hydrodynamic Theory ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Lubricating Film ◽  
Single Function ◽  
Load Carrying

This paper presents an experimental procedure to evaluate the load-carrying capacity of a fixed-incline slider bearing (dimensionless load W versus convergence ratio K) using a slider-on-disk lubricating film test rig. In general, the applied load is the dependent variable and is directly measured for different convergence ratios such that the relation of the load-carrying capacity W and the convergence ratio K can be obtained. The load and slider inclination are fixed in the present approach, and the film thickness is measured at different speeds. As the dimensionless load can be a function of speed and film thickness, the variation of load-carrying capacity with respect to speed can be obtained even under a constant load and a fixed incline. It is shown that the measured load-carrying capacity is lower than that predicted by the classical hydrodynamic theory. Nevertheless, the experimental results acquire the same trend in the variation of dimensionless loads with convergence ratios. The theory holds that the load-carrying capacity is a single function of the convergence ratio. However, the experimental results show that the dimensionless load-carrying capacity is affected by the inclination angle of the slider, load, and the properties of lubricating oils.

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.

The effect of V-shape protruded and dimple textured on the load-carrying capacity and coefficient of friction of hydrodynamic journal bearing: A comparative numerical study

2020 ◽  
pp. 135065012093500
Author(s):  
Sanjay Sharma ◽  
Aniket Sharma ◽  
Gourav Jamwal ◽  
Rajeev Kumar Awasthi
Keyword(s):  
Coefficient Of Friction ◽  
Carrying Capacity ◽  
Performance Enhancement ◽  
Numerical Study ◽  
Geometrical Parameters ◽  
Load Carrying Capacity ◽  
Enhancement Ratio ◽  
Load Carrying ◽  
The Coefficient Of Friction ◽  
Computing Performance

The present comparative numerical study is between V-shape protruded, dimple textured, and untextured bearing. The performance parameters in terms of the load-carrying capacity and coefficient of friction are computed by solving governing Reynold’s equation of the lubricant fluid flow. The governing equation is solved by the finite element method by assuming that the fluid is Newtonian and isoviscous in nature. The effect of eccentricity ratios, texture distribution, texture heights, and texture depths are considered for the analysis in both textured bearings. From simulated results, the load-carrying capacity and coefficient of friction is found to be maximum for protruded textured bearing in full textured region and first half-textured region respectively as compared to untextured bearings. Finally, optimal operating and geometrical parameters of textured bearing is obtained by computing performance enhancement ratio, which is the ratio of the load-carrying capacity to the coefficient of friction. The maximum value of the performance enhancement ratio is found for protruded and dimple textured bearing in full texturing and second half-region corresponding to the eccentricity ratio of 0.8 and 0.6 respectively at texture height and depth of 0.4.

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.

A Theory of Liquid-Solid Lubrication in Elastohydrodynamic Regime

1989 ◽  
Vol 111 (3) ◽  
pp. 440-444 ◽  
Author(s):  
M. M. Khonsari ◽  
S. H. Wang ◽  
Y. L. Qi
Keyword(s):  
Particle Size ◽  
Film Thickness ◽  
Carrying Capacity ◽  
Theoretical Study ◽  
Solid Particles ◽  
Solid Lubrication ◽  
Load Carrying Capacity ◽  
Line Contact ◽  
Load Carrying ◽  
Bounding Surfaces

A theoretical study of the effectiveness of solid particles dispersed in oil in the elastohydrodynamic line contact is presented. The analysis includes the variation of the viscosity and density of the lubricant as a function of pressure. The deformation of solid particles and that of the bounding surfaces are taken into consideration. Results are presented for the variation of the film thickness and the load carrying capacity as a function of the particle size, concentration, and properties of various types of particles.

Evaluation of Dynamic Load-Carrying Capacity for Free-Floating Space Manipulators

2015 ◽  
Vol 713-715 ◽  
pp. 795-799 ◽  
Author(s):  
Yong Liu ◽  
Qing Xuan Jia ◽  
Gang Chen ◽  
Han Xu Sun ◽  
Jun Jie Peng
Keyword(s):  
Dynamic Load ◽  
Carrying Capacity ◽  
Function Method ◽  
Feasible Region ◽  
Penalty Function Method ◽  
Load Carrying Capacity ◽  
One Dimensional ◽  
Space Manipulators ◽  
Load Carrying ◽  
Point To Point

Two kinds of dynamic load-carrying capacity (DLCC) evaluation methods for free-floating space manipulators (FFSM) in two typical on-orbit operating missions are proposed in this paper. DLCC evaluation is transformed into nonlinear programming problem (NPP) by introducing load-carrying coefficient to measure DLCC: in point-to-point task, penalty function method is adopted to approach the boundary of feasible region rapidly, then DLCC can be obtained through following iterations; in trajectory tracking task, NPP is solved by using multiple one-dimensional search, the dynamic load-carrying coefficient in discontinuous feasible region can be quickly solved through adjusting the searching boundary constantly. The effectiveness of the mentioned methods is verified by simulations.

Numerical Analysis of Hydrodynamic Journal Bearing Lubrication using Computational Fluid Dynamics and Fluid Structure Interaction Approach

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
D.Y. Dhande ◽  
D.W. Pande
Keyword(s):  
Response Surface ◽  
Carrying Capacity ◽  
Computation Time ◽  
Computational Time ◽  
Maximum Pressure ◽  
Load Carrying Capacity ◽  
Lubricating Film ◽  
Response Surface Optimization ◽  
Load Carrying ◽  
Interaction Approach

Now-a-days, journal bearings are subjected to severe loads and higher operating speeds causing generation of high hydrodynamic pressures which in turn deform the bearing shell thus modifying the lubricating film in the operating region. Hence, there is need for optimized bearing performance parameter estimation considering the realistic change in lubricating film along with less computational time. In this paper, response surface optimization module coupled with static structural and fluent, available in ANSYS workbench is used for analysing the performance of the bearing. The optimization is based on Response Surface evaluations. It has been observed that the computation time is considerably reduced. The bearing is analysed for various rotational speeds and eccentricity ratios to obtain load carrying capacity and pressure distribution. It is observed that the results are following the expected trend i.e. as speed increases the load carrying capacity as well as maximum pressure is increasing.

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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