scholarly journals A Study on the Performance of a Magnetic-Fluid-Based Hydrodynamic Short Journal Bearing

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
N. S. Patel ◽  
D. P. Vakharia ◽  
G. M. Deheri
Keyword(s):  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Fluid Pressure ◽  
Point Of View ◽  
Graphical Form ◽  
Load Carrying Capacity ◽  
Additional Degree ◽  
Load Carrying

Efforts have been made to study and analyze the performance of a hydrodynamic short journal bearing under the presence of a magnetic fluid lubricant. With the usual assumptions of hydrodynamic lubrication, the associated Reynolds equation for the fluid pressure is solved with appropriate boundary conditions. In turn, this is then used to calculate the load-carrying capacity which results in the calculation of friction. The computed results presented in graphical form suggest that the bearing system registers an improved performance owing to the magnetic fluid as compared to the conventional lubricant. It is clearly observed that the load-carrying capacity increases nominally while the coefficient of friction decreases significantly. Besides, it is seen that the bearing can support a load even when there is no flow of lubricant. In addition, this type of study may offer an additional degree of freedom from design point of view in terms of the forms of the magnitude of the magnetic fluid.

The Granular Lubricated Journal Bearing: Evidence of Lift Formation

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Venkata K. Jasti ◽  
Martin C. Marinack ◽  
Deepak Patil ◽  
C. Fred Higgs
Keyword(s):  
Carrying Capacity ◽  
Granular Flow ◽  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Flow Behavior ◽  
Extreme Environments ◽  
Granular Flows ◽  
Load Carrying Capacity ◽  
Load Carrying

This work demonstrates that granular flows (i.e., macroscale, noncohesive spheres) entrained into an eccentrically converging gap can indeed actually exhibit lubrication behavior as prior models postulated. The physics of hydrodynamic lubrication is quite well understood and liquid lubricants perform well for conventional applications. Unfortunately, in certain cases such as high-speed and high-temperature environments, liquid lubricants break down making it impossible to establish a stable liquid film. Therefore, it has been previously proposed that granular media in sliding convergent interfaces can generate load carrying capacity, and thus, granular flow lubrication. It is a possible alternative lubrication mechanism that researchers have been exploring for extreme environments, or wheel-regolith traction, or for elucidating the spreadability of additive manufacturing materials. While the load carrying capacity of granular flows has been previously demonstrated, this work attempts to more directly uncover the hydrodynamic-like granular flow behavior in an experimental journal bearing configuration. An enlarged granular lubricated journal bearing (GLJB) setup has been developed and demonstrated. The setup was made transparent in order to visualize and video capture the granular collision activity at high resolution. In addition, a computational image processing program has been developed to process the resulting images and to noninvasively track the “lift” generated by granular flow during the journal bearing operation. The results of the lift caused by granular flow as a function of journal rotation rate are presented as well.

CFD analysis of load-carrying capacity of hydrodynamic lubrication on a water-lubricated journal bearing

2015 ◽  
Vol 67 (1) ◽  
pp. 30-37 ◽  
Author(s):  
Gao Gengyuan ◽  
Yin Zhongwei ◽  
Jiang Dan ◽  
Zhang Xiuli
Keyword(s):  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Radial Clearance ◽  
Load Carrying Capacity ◽  
Cfd Analysis ◽  
Hydrodynamic Load ◽  
Oil And Grease ◽  
Content Type ◽  
Load Carrying

Purpose – The purpose of this paper is to improve hydrodynamic load-carrying capacity of a water-lubricated journal bearing by a new bush structure. Water-lubricated bearing is becoming more and more popular since it is environmentally friendly and saves energy. However, contrary to oil and grease-lubricated bearings, water-lubricated bearing is limited in many situations due to its low hydrodynamic load-carrying capacity. Design/methodology/approach – The present article proposes a new bearing bush, with a transition-arc structure, which is favorable for increasing hydrodynamic load-carrying capacity. Hydrodynamic load-carrying capacity was calculated by means of three-dimensional computational fluid dynamics (3-D CFD) analysis. Several variants of a journal bearing with a transition-arc structure of different dimensions are analyzed, while the radial clearance of the bearing, eccentricity ratio and the velocity of the journal remain unchanged. Findings – The results show that obvious changes are found in hydrodynamic load-carrying capacity of a water-lubricated journal bearing. For different width over diameter (L/D) bearing ratios, the relationship between hydrodynamic load-carrying capacity and the magnitude of the transition-arc structure dimension is researched. Originality/value – The research presented here leads to a design reference guideline that could be used by the designer engineer to design smart journal bearings for improving the hydrodynamic load-carrying capacity.

THE CHANGE OF FRICTION AND LOAD- CARRYING CAPACITY OF THE JOURNAL BEARING WITH THE CONSIDERATION OF THE OIL AGEING

Tribologia ◽  
2016 ◽  
Vol 269 (5) ◽  
pp. 171-181
Author(s):  
Grzegorz SIKORA ◽  
Andrzej MISZCZAK
Keyword(s):  
Shear Rate ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Hydrodynamic Pressure ◽  
Load Carrying Capacity ◽  
Motor Oil ◽  
Temperature Influence ◽  
Load Carrying ◽  
Viscosity Changes

This paper presents numerical calculations of the hydrodynamic pressure distribution, carrying capacity, and friction coefficient in the gap of a journal bearing. The analysed bearing is lubricated using motor oil. In this paper, oil ageing and temperature influence on viscosity are taken into account. Viscosity changes in the pressure and shear rate are not considered. These changes will be considered in other papers. For the hydrodynamic lubrication analysis, laminar flow of the lubrication fluid and non-isothermal lubrication model of the journal bearing were assumed. As the constitutive equation, the classical, Newtonian model was used. This model was extended by the viscosity changes in temperature and exploitation time. For the considerations, the cylindrical journal bearing with the finite length and smooth bearing, with the full angle of wrap were taken.

scholarly journals Two-scale homogenization of hydrodynamic lubrication in a mechanical seal with isotropic roughness based on the Elrod cavitation algorithm

2021 ◽  
pp. 135065012110176
Author(s):  
Yanxiang Han ◽  
Qingen Meng ◽  
Gregory de Boer
Keyword(s):  
Surface Topography ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Tribological Performance ◽  
Stribeck Curve ◽  
Polar Coordinate System ◽  
Load Carrying Capacity ◽  
Mechanical Seal ◽  
Macro Scale ◽  
Load Carrying

A two-scale homogenization method for modelling the hydrodynamic lubrication of mechanical seals with isotropic roughness was developed and presented the influence of surface topography coupled into the lubricating domain. A linearization approach was derived to link the effects of surface topography across disparate scales. Solutions were calculated in a polar coordinate system derived based on the Elrod cavitation algorithm and were determined using homogenization of periodic simulations describing the lubrication of a series of surface topographical features. Solutions obtained for the hydrodynamic lubrication regime showed that the two-scale homogenization approach agreed well with lubrication theory in the case without topography. Varying topography amplitude demonstrated that the presence of surface topography improved tribological performance for a mechanical seal in terms of increasing load-carrying capacity and reducing friction coefficient in the radial direction. A Stribeck curve analysis was conducted, which indicated that including surface topography led to an increase in load-carrying capacity and a reduction in friction. A study of macro-scale surface waviness showed that the micro-scale variations observed were smaller in magnitude but cannot be obtained without the two-scale method and cause significant changes in the tribological performance.

Strengthening and widening of steel pony truss bridges

1977 ◽  
Vol 4 (2) ◽  
pp. 214-225
Author(s):  
Baidar Bakht ◽  
Paul F. Csagoly
Keyword(s):  
Traffic Safety ◽  
Carrying Capacity ◽  
Point Of View ◽  
Load Carrying Capacity ◽  
Truss Bridges ◽  
Load Carrying ◽  
Live Loads ◽  
Pros And Cons ◽  
Pony Truss Bridge ◽  
Truss Bridge

There are many thousands of existing pony truss bridges in North America which were constructed in the earlier part of this century and are still serving as important traffic carriers. The present economic situation demands that these bridges should usefully serve their purpose for as long as is safely possible.These bridges could be found inadequate for either or both of the following reasons. With the exception of remote areas, operational traffic safety would require two 12-ft lanes plus adequate shoulders. Many of these old bridges are therefore unsatisfactory from the geometrical point of view. Some bridges were designed for live loads that are only a fraction of present commercial vehicle weights.A computer-oriented method of rigorous analysis of lateral buckling behaviour of pony truss bridges is briefly discussed. The method is implemented through a computer program which has been validated by experimental data. It is expected that the program would predict realistic values of load-carrying capacity of such bridges and would help to avoid many an unnecessary replacement.Various methods of strengthening and widening pony truss bridges, and their pros and cons, are discussed. It is shown that the strengthening of a few components of a pony truss bridge does not always lead to an increase in the load-carrying capacity of the bridge.

Static characteristics of misaligned multiple axial groove water-lubricated bearing in the turbulent regime

2016 ◽  
Vol 231 (3) ◽  
pp. 385-398 ◽  
Author(s):  
Ravindra Mallya ◽  
Satish B Shenoy ◽  
Raghuvir Pai
Keyword(s):  
Reynolds Number ◽  
Friction Coefficient ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Load Capacity ◽  
Turbulent Regime ◽  
Load Carrying Capacity ◽  
Static Characteristics ◽  
Load Carrying ◽  
Turbulence Effects

The static characteristics of misaligned three-axial water-lubricated journal bearing in the turbulent regime are analyzed for groove angles 36° and 18°. Ng and Pan’s turbulence model is applied to study the turbulence effects in the journal bearing. The static parameters such as load-carrying capacity, friction coefficient, and side leakage are found for different degree of misalignment (DM). The change in flow regime of the lubricant from laminar to turbulent and the increase in misalignment, improved the load capacity of the bearing. For lightly loaded bearings, the friction coefficient of the bearing increased with the increase in Reynolds number.

Partially Textured Slider and Journal Bearing Analysis

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
T. V. V. L. N. Rao ◽  
A. M. A. Rani ◽  
T. Nagarajan ◽  
F. M. Hashim
Keyword(s):  
Friction Coefficient ◽  
Coefficient Of Friction ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Bearing Analysis

The present study examines the influence of partial texturing of bearing surfaces on improvement in load capacity and reduction in friction coefficient for slider and journal bearing. The geometry of partially textured slider and journal bearing considered in this work composed of a number of successive regions of groove and land configurations. The nondimensional pressure expressions for the partially textured slider and journal bearing are derived taking into consideration of texture geometry and extent of partial texture. Partial texturing has a potential to generate load carrying capacity and reduce coefficient of friction, even for nominally parallel bearing surfaces.

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.

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