scholarly journals Numerical Study of Surface Roughness and Magnetic Field between Rough and Porous Rectangular Plates

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ramesh B. Kudenatti ◽  
Shalini M. Patil ◽  
P. A. Dinesh ◽  
C. V. Vinay
Keyword(s):  
Magnetic Field ◽  
Surface Roughness ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Hartmann Number ◽  
Numerical Study ◽  
Mathematical Formulation ◽  
Load Carrying Capacity ◽  
Parallel Plates ◽  
Load Carrying

This paper theoretically examines the combined effects of surface roughness and magnetic field between two rectangular parallel plates of which the upper plate has roughness structure and the lower plate has porous material in the presence of transverse magnetic field. The lubricating fluid in the film region is assumed to be Newtonian fluid (linearly viscous and incompressible fluid). This model consists of mathematical formulation of the problem with appropriate boundary conditions and solution numerically by finite difference based multigrid method. The generalized average modified Reynolds equation is derived for longitudinal roughness using Christensen’s stochastic theory which assumes that the height of the roughness asperity is of the same order as the mean separation between the plates. We obtain the bearing characteristics such as pressure distribution and load carrying capacity for various values of roughness, Hartmann number, and permeability parameters. It is observed that the pressure distribution and load carrying capacity were found to be more pronounced for increasing values of roughness parameter and Hartmann number; whereas these are found to be decreasing for increasing permeability compared to their corresponding classical cases. The physical reasons for these characters are discussed in detail.

Performance characteristics of journal bearings (porous type): A coupled solution using Hartmann number and roughness parameter

2019 ◽  
Vol 234 (5) ◽  
pp. 668-675
Author(s):  
GK Kalavathi ◽  
FA Najar ◽  
MG Vasundhara
Keyword(s):  
Magnetic Field ◽  
Carrying Capacity ◽  
Hartmann Number ◽  
Slip Surface ◽  
Hydrodynamic Lubrication ◽  
Magnetic Field Effect ◽  
Roughness Parameter ◽  
Load Carrying Capacity ◽  
Integral Forms ◽  
Load Carrying

The influence of magnetic field and roughness factor on long journal (porous) bearing with heterogeneous slip/no-slip surface has been described in this paper. Assumptions of hydrodynamic lubrication theory and Navier slip relation were employed during the investigation, and the generalized Reynolds equation for the oil film pressure was obtained using appropriate boundary conditions and the expressions for pressure distribution and load-carrying capacity as a function of Hartmann number, permeability parameter, roughness parameter, and slip parameter were derived in integral forms. Integrals involved are evaluated by using Simpsons 1/3rd rule and Gauss quadrature 16-point formula in MATLAB code. Christensen stochastic process is adopted to study the roughness behavior. In the present analysis, it has been revealed that there is a noticeable escalation in the load-carrying capacity with the embodiment of magnetic field effect, which enables the journal (rotating part) to levitate inside the domain of bearing (stationary part) that indeed supports the lubricant performance.

The Finite Magnetohydrodynamic Journal Bearing

1964 ◽  
Vol 86 (3) ◽  
pp. 445-448 ◽  
Author(s):  
D. C. Kuzma
Keyword(s):  
Magnetic Field ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Numerical Data ◽  
Load Carrying Capacity ◽  
Radial Magnetic Field ◽  
Electrically Conducting ◽  
Load Carrying ◽  
The Magnetic Field

An analysis of a finite journal bearing is presented for the case of an electrically conducting fluid in the presence of a radial magnetic field. The magnetohydrodynamic form of the two-dimensional Reynolds equation is derived and solved numerically for the pressure distribution. The load-carrying capacity and torque are determined from the pressure distribution. Numerical data for nonconducting bearing surfaces are compared with the data from the ordinary journal bearing. It is shown that the load-carrying capacity and torque are increased by the application of the magnetic field.

The Magnetohydrodynamic Journal Bearing

1963 ◽  
Vol 85 (3) ◽  
pp. 424-427 ◽  
Author(s):  
Dennis C. Kuzma
Keyword(s):  
Magnetic Field ◽  
Pressure Distribution ◽  
Carrying Capacity ◽  
Journal Bearing ◽  
Numerical Data ◽  
Conducting Fluid ◽  
Load Carrying Capacity ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Load Carrying

An analysis of an infinite journal bearing is presented for the case of an electrically conducting fluid in the presence of a magnetic field. The magnetohydrodynamic form of Reynolds’ bearing equation is derived and solved for the pressure distribution. The load carrying capacity is determined from the pressure distribution. Numerical data are presented for nonconducting bearing surfaces. These data are compared with the data from the ordinary journal bearing. It is shown that the load carrying capacity is increased by the application of a magnetic field.

scholarly journals Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

2021 ◽  
Author(s):  
Daniel Müller ◽  
Jens Stahl ◽  
Anian Nürnberger ◽  
Roland Golle ◽  
Thomas Tobie ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Carrying Capacity ◽  
Bending Strength ◽  
Tooth Root ◽  
Load Carrying Capacity ◽  
Near Surface ◽  
Load Carrying ◽  
Involute Gears ◽  
Cut Surface

AbstractThe manufacturing of case-hardened gears usually consists of several complex and expensive steps to ensure high load carrying capacity. The load carrying capacity for the main fatigue failure modes pitting and tooth root breakage can be increased significantly by increasing the near surface compressive residual stresses. In earlier publications, different shear cutting techniques, the near-net-shape-blanking processes (NNSBP’s), were investigated regarding a favorable residual stress state. The influence of the process parameters on the amount of clean cut, surface roughness, hardness and residual stresses was investigated. Furthermore, fatigue bending tests were carried out using C-shaped specimens. This paper reports about involute gears that are manufactured by fineblanking. This NNSBP was identified as suitable based on the previous research, because it led to a high amount of clean cut and favorable residual stresses. For the fineblanked gears of S355MC (1.0976), the die edge radii were varied and the effects on the cut surface geometry, hardness distribution, surface roughness and residual stresses are investigated. The accuracy of blanking the gear geometry is measured, and the tooth root bending strength is determined in a pulsating test rig according to standardized testing methods. It is shown that it is possible to manufacture gears by fineblanking with a high precision comparable to gear hobbing. Additionally, the cut surface properties lead to an increased tooth root bending strength.

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.

Performance analysis of rough surface hybrid thrust bearing with elliptical dimples

2020 ◽  
pp. 135065012093198
Author(s):  
Vivek Kumar ◽  
Satish C Sharma
Keyword(s):  
Surface Roughness ◽  
Carrying Capacity ◽  
Machining Process ◽  
Fluid Film ◽  
Textured Surface ◽  
Stiffness Coefficient ◽  
Load Carrying Capacity ◽  
Power Losses ◽  
Load Carrying ◽  
Film Stiffness

Surface roughness is inherent to all machining processes. Therefore, even a high precision machining process renders micro-roughness to some extent on the surface of conventional materials. The asperities height of many rough engineering surfaces follows Gaussian distribution. The surface roughness on the bearing surface may significantly affect the bearing performance. Surface texturing is emerging as a new technique to improve the tribological behavior of the mating surfaces. Usually dimensions/height of micro-roughness is of order of the depth of surface textures in fluid film bearings. Neglecting micro-roughness while numerically simulating a textured surface bearing may generate inaccurate bearing performance data. In presented work, finite element simulation of textured surface hybrid thrust bearings has been performed. Surface texture is provided over thrust pad in the form of regular arrays of elliptical dimples. A parametric optimization is carried out to determine optimum attributes of elliptical dimple (axis, depth, texture length and orientation) so that the load-carrying capacity and fluid film stiffness should be maximized and film frictional power losses should be minimized. Use of textured surface (with optimum elliptical dimple attributes) results into a significant enhancement in load-carrying capacity (91.3%), film stiffness coefficient (+98.8%) and reduction in frictional power losses (−48.3%). It is also observed that elliptical dimple and micro-roughness (transverse orientation) generate synergistic effects in further enhancing the load-carrying capacity (+101.4%) and film stiffness coefficient (+112%) of the bearing.

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.

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.

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