The Influence of Surface Tension on Bearings Lubricated With Bubbly Liquids

1980 ◽  
Vol 102 (1) ◽  
pp. 91-96 ◽  
Author(s):  
E. H. Smith
Keyword(s):  
Surface Tension ◽  
Bubble Surface ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Bubbly Liquids ◽  
Viscous Forces ◽  
Tilting Pad ◽  
Load Carrying ◽  
Bearing Load ◽  
Order Of Magnitude

An order of magnitude analysis of the Rayleigh-Plesset equation of motion of a bubble surface reveals that inertia and viscous forces can be ignored in realistic bearing configurations and that surface tension plays an important role. The influence of gas bubbles in liquid lubrication is examined with particular reference to the steadily-loaded plane-inclined slider-bearing. Load carrying capacity is virtually unaffected by lubricant gasification. The centre of pressure can be considerably modified, depending partially on the value of a new dimensionless group—the configuration number φ. It appears that the tilting-pad thrust bearing will sometimes be unstable in operation, resulting in bearing failure.

The Effects on Bearing Load-Carrying Capacity of Two-Sided Striated Roughness

1974 ◽  
Vol 96 (4) ◽  
pp. 554-558 ◽  
Author(s):  
S. K. Rhow ◽  
H. G. Elrod
Keyword(s):  
Carrying Capacity ◽  
Multiple Scale ◽  
Load Carrying Capacity ◽  
Transient Effects ◽  
Slider Bearing ◽  
Scale Method ◽  
Load Carrying ◽  
Bearing Load ◽  
Order Of Magnitude ◽  
Final Equation

The multiple-scale method which was earlier employed for lubricating films with striated roughness on one of two opposing surfaces is here extended to include striated roughness on both surfaces. In some papers, the transient effects due to the roughness have been neglected. However, the present analysis shows that the term representing these effects is of the same order of magnitude as others retained in the final equation governing the average pressure. As an example, it is shown that with the same overall roughness characteristics, the load-carrying capacity of an infinitely wide slider bearing varies according to how the same roughness is distributed on opposing surfaces.

scholarly journals EXPERIMENTAL STUDIES OF PRESSURE DISTRIBUTION IN TILTING PAD THRUST BEARING WITH SINGLE CONTINUOUS SURFACE PROFILED SECTOR SHAPED PADS

2012 ◽  
pp. 129-133
Author(s):  
ABHIJEET PATIL ◽  
P.B. SHINDE ◽  
S.P. CHAVAN
Keyword(s):  
Carrying Capacity ◽  
Thrust Bearing ◽  
Experimental Studies ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Design Data ◽  
Hydrodynamic Bearing ◽  
Tilting Pad ◽  
Load Carrying ◽  
Continuous Surface

The effect of the film shape on the load carrying capacity of a hydrodynamically lubricated bearing has not been considered an important factor in the past. Flat faced tapered bearing and the Raileigh's step bearing of constant film thickness have been the primary forms of film shapes for slider bearing studies and design data developments. There are indications in the literature that surface profiling/texturing can have significant and positive influence on the load carrying capacity of hydrodynamic pad thrust bearings. Therefore, the objective of this paper is to compare the experimental results of pressure temperature distributions in slider bearing with flat surface and with different single continuous surface profiled (Cycloidal,Catenoidal,Quadratic) sector shaped pads. Pressure results presented in this paper can provide a platform for validation of theoretical models. An experimental study has been performed to investigate the influence of single continuous surface profiled sector shaped pads in tilting pad thrust bearing. It has been found that with cycloidal shaped surface profiled sector shaped pads the pressure generated within fluid film is enhanced which in turn causes enhancement in load bearing capacity of hydrodynamic bearing.

Design and fabrication of the tilting-pad thrust bearing surface profile

2018 ◽  
Vol 70 (8) ◽  
pp. 1402-1407
Author(s):  
Zhanchao Wang ◽  
Fei Guo ◽  
Ying Liu ◽  
Xiangfeng Liu ◽  
Yuming Wang
Keyword(s):  
Thrust Bearing ◽  
Design Method ◽  
Surface Profile ◽  
Load Carrying Capacity ◽  
Laser Method ◽  
Content Type ◽  
Tilting Pad ◽  
Load Carrying ◽  
Bearing Load ◽  
Thrust Pad

PurposeThis paper aims to design a new surface profile with simpler processing technology, which makes the bearing load carrying capacity (LCC) close to that of conventional tilting-pad thrust bearing.Design/methodology/approachThe paper analyzes the LCC of the thrust pad with crown profile and designs a new profile, whose performance is similar to the crown profile. The laser method is introduced to fabricate the new profile. The profile with tiny crown height can be fabricated by the laser with the proper parameters.FindingsIt was found that there is an optimum value, which is best in terms of the capacity of tilting-pad thrust bearing reach. The new profile with proper parameters can replace the crown profile.Originality/valueThe new profile can replace the crown profile and is easier to be made. The new design method could be adopted for designing the pad surface profile of the tilting-pad thrust bearing.

On the Significance of the Inlet Pressure Build-Up in the Design of Tilting-Pad Bearings

1990 ◽  
Vol 112 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Cz. M. Rodkiewicz ◽  
K. W. Kim ◽  
J. S. Kennedy
Keyword(s):  
Thrust Bearing ◽  
Ambient Pressure ◽  
Inlet Pressure ◽  
Load Carrying Capacity ◽  
Integral Theorem ◽  
Lubricating Film ◽  
Tilting Pad ◽  
Load Carrying ◽  
Momentum Integral ◽  
Entrance Pressure

An operating tilting-pad thrust bearing generates a fore-region which is responsible for maintaining, at the bearing entrance, a pressure which is higher than the ambient pressure. This entrance pressure, in the presented analysis, is obtained by applying to the fore-region the momentum integral theorem. The solution of the lubricating film region is then obtained by using this modified inlet pressure. This solution yields the pressure distribution, the load carrying capacity, the film ratio and the frictional force for several values of the modified Reynolds number and various pivot positions. The analysis shows that there is a significant influence of the fore-region pressure on the bearing performance and that to properly design efficient tilting-pad bearing this effect should be taken into consideration.

A Comparison of Porous Structures on the Performance of a Slider Bearing with Surface Roughness in Couple Stress Fluid Film Lubrication

2015 ◽  
Vol 813-814 ◽  
pp. 921-937
Author(s):  
P.S. Rao ◽  
Santosh Agarwal
Keyword(s):  
Surface Roughness ◽  
Carrying Capacity ◽  
Couple Stress ◽  
Type Equation ◽  
Random Variable ◽  
Couple Stress Fluid ◽  
Load Carrying Capacity ◽  
Porous Structures ◽  
Slider Bearing ◽  
Load Carrying

This paper presents the theoretical study and analyzes the comparison of porous structures on the performance of a couple stress fluid based on rough slider bearing. The globular sphere model of Kozeny-Carman and Irmay’s capillary fissures model have been subjected to investigations. A more general form of surface roughness is mathematically modeled by a stochastic random variable with non-zero mean, variance and skewness. The stochastically averaged Reynolds type equation has been solved under suitable boundary conditions to obtain the pressure distribution in turn which gives the expression for the load carrying capacity, frictional force and coefficient of friction. The results are illustrated by graphical representations which show that the introduction of combined porous structure with couple stress fluid results in an enhanced load carrying capacity more in the case of Kozeny-Carman model as compared to Irmay’s model.

scholarly journals A STUDY OF FERROFLUID LUBRICATION BASED ROUGH SINE FILM SLIDER BEARING WITH ASSORTED POROUS STRUCTURE

2019 ◽  
Vol 59 (2) ◽  
pp. 144-152
Author(s):  
Mohmmadraiyan M. Munshi ◽  
Ashok R. Patel ◽  
Gunamani B. Deheri
Keyword(s):  
Porous Structure ◽  
Carrying Capacity ◽  
Graphical Representation ◽  
Negative Impact ◽  
Positive Impact ◽  
Numerical Approach ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Load Carrying ◽  
The Impact

This paper attempts to study a ferrofluid lubrication based rough sine film slider bearing with assorted porous structure using a numerical approach. The fluid flow of the system is regulated by the Neuringer-Rosensweig model. The impact of the transverse surface roughness of the system has been derived using the Christensen and Tonder model. The corresponding Reynolds’ equation has been used to calculate the pressure distribution which, in turn, has been the key to formulate the load carrying capacity equation. A graphical representation is made to demonstrate the calculated value of the load carrying capacity which is a dimensionless unit. The numbers thus derived have been used to prove that ferrofluid lubrication aids the load carrying capacity. The study suggests that the positive impact created by magnetization in the case of negatively skewed roughness helps to partially nullify the negative impact of the transverse roughness. Further investigation implies that when the Kozeny-Carman’s model is used, the overall performance is enhanced. The Kozeny-Carman’s model is a form of an empirical equation used to calculate permeability that is dependent on various parameters like pore shape, turtuosity, specific surface area and porosity. The success of the model can be accredited to its simplicity and efficiency to describe measured permeability values. The obtained equation was used to predict the permeability of fibre mat systems and of vesicular rocks.

Hydrodynamic Lubrication of Finite Slider Bearings: Effect of One Dimensional Film Shape, and Their Computer Aided Optimum Designs

1983 ◽  
Vol 105 (1) ◽  
pp. 48-63 ◽  
Author(s):  
C. Bagci ◽  
A. P. Singh
Keyword(s):  
Numerical Solution ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Hydrodynamic Lubrication ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Design Data ◽  
Slider Bearings ◽  
Load Carrying ◽  
Computer Aided

The effect of the film shape on the load carrying capacity of a hydrodynamically lubricated bearing has not been considered an important factor in the past. Flat-faced tapered bearing and the Raileigh’s step bearing of constant film thickness have been the primary forms of film shapes for slider bearing studies and design data developments. This article, by the computer aided numerical solution of the Reynolds equation for two dimensional incompressible lubricant flow, investigates hydrodynamically lubricated slider bearings having different film shapes and studies the effect of the film shape on the performance characteristics of finite bearings; and it shows that optimized bearing with film shapes having descending slope toward the trailing edge of the bearing has considerably higher load carrying capacity than the optimized flat-faced tapered bearing of the same properties. For example the truncated cycloidal film shape yields 26.3 percent higher load carrying capacity for Lz/Lx = 1 size ratio, and 44 percent higher for Lz/Lx = 1/2. The article then presents charts for the optimum designs of finite slider bearings having tapered, exponential, catenoidal, polynomial, and truncated-cycloidal film shapes, and illustrates their use in numerical bearing design examples. These charts also furnish information on flow rate, side leakage, temperature rise, coefficient of friction, and friction power loss in optimum bearings. Appended to the article are analytical solutions for infinitely wide bearings with optimum bearing characteristics. The computer aided numerical solution of the Reynolds equation in most general form is presented by which finite or infinitely wide hydrodynamically or hydrostatically lubricated bearings, externally pressurized or not, can be studied. A digital computer program is made available.

An Approximate Solution for the Infinitely Long, Gas Lubricated Slider Bearing

1965 ◽  
Vol 87 (4) ◽  
pp. 1085-1086
Author(s):  
H. J. Sneck
Keyword(s):  
Exact Solution ◽  
Approximate Solution ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Load Carrying ◽  
Numerical Design ◽  
The One ◽  
Design Calculations

The only exact solution for the infinitely long, gas-lubricated slider bearing is the one obtained by Harrison [1] for the plane wedge isothermal film. The resultant formulas for the pressure distribution and load-carrying capacity are complicated and therefore quite cumbersome in numerical design calculations. In the analysis to follow, a simplified, approximate solution is developed which can be applied to any infinitely long slider geometry.

Pressure Buildup Mechanism in a Textured Inlet of a Hydrodynamic Contact

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Samuel Cupillard ◽  
Michel J. Cervantes ◽  
Sergei Glavatskih
Keyword(s):  
Velocity Profile ◽  
Carrying Capacity ◽  
Flow Analysis ◽  
Maximum Efficiency ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Pressure Buildup ◽  
Flow Recirculation ◽  
Recirculating Flow ◽  
Load Carrying

A flow analysis is carried out for an inclined slider bearing with the aim of showing the governing mechanism at conditions where an optimum in load carrying capacity is achieved. The effects of surface texture on pressure buildup and load carrying capacity are explained for a textured slider bearing geometry. Numerical simulations are performed for laminar, steady, and isothermal flows. The energy transferred to the fluid from the moving wall is converted into pressure in the initial part of the converging contact and into losses in the second part. The convergence ratio can be increased, in order to get the greatest pressure gradient, until the limiting value where flow recirculation begins to occur. The texture appears to achieve its maximum efficiency when its depth is such that the velocity profile is stretched at its maximum extent without incurring incoming recirculating flow. The wall profile shape controlling the velocity profile can be optimized for many hydrodynamic contacts.

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.

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