Effect of surface roughness and elastic deformation on the performance of a magnetic fluid-based squeeze film in rotating porous annular plates

2014 ◽  
Vol 66 (3) ◽  
pp. 490-497
Author(s):  
Mukesh E. Shimpi ◽  
Gunamani Deheri
Keyword(s):  
Elastic Deformation ◽  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Type Equation ◽  
Squeeze Film ◽  
Rotational Inertia ◽  
Load Carrying Capacity ◽  
Content Type ◽  
Annular Plates ◽  
Load Carrying

Purpose – The purpose of this paper is to study and analyse the behaviour of a magnetic fluid-based squeeze film between rotating transversely rough porous annular plates, taking the elastic deformation into consideration. Design/methodology/approach – The stochastic film thickness characterizing the roughness is considered to be asymmetric with non-zero mean and variance and skewness while a magnetic fluid is taken as the lubricant. The associated stochastically averaged Reynolds-type equation is solved with appropriate boundary conditions to obtain the pressure distribution, which in turn is used to derive the expression for the load-carrying capacity. Findings – It is observed that the roughness of the bearing surfaces affects the performance adversely, although the bearing registers an improved performance owing to the magnetic fluid lubricant. Also, it is seen that the deformation causes reduced load-carrying capacity. The bearing can support a load even in the absence of flow, unlike the case of conventional lubricants. Originality/value – The originality of the paper lies in the fact that the negative effect of porosity, deformation and standard deviation can be minimized to some extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by suitably choosing the rotational inertia and aspect ratio. This effect becomes sharper when negative variance occurs.

scholarly journals Magnetic Fluid-Based Squeeze Film Behaviour in Curved Porous-Rotating Rough Annular Plates and Elastic Deformation Effect

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
M. E. Shimpi ◽  
G. M. Deheri
Keyword(s):  
Elastic Deformation ◽  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Random Variable ◽  
Squeeze Film ◽  
Rotational Inertia ◽  
Load Carrying Capacity ◽  
Annular Plates ◽  
Load Carrying ◽  
Transverse Roughness

Efforts have been directed to study and analyze the squeeze film performance between rotating transversely rough curved porous annular plates in the presence of a magnetic fluid lubricant considering the effect of elastic deformation. A stochastic random variable with nonzero mean, variance, and skewness characterizes the random roughness of the bearing surfaces. With the aid of suitable boundary conditions, the associated stochastically averaged Reynolds' equation is solved to obtain the pressure distribution in turn, which results in the calculation of the load-carrying capacity. The graphical representations establish that the transverse roughness, in general, adversely affects the performance characteristics. However, the magnetization registers a relatively improved performance. It is found that the deformation causes reduced load-carrying capacity which gets further decreased by the porosity. This investigation tends to indicate that the adverse effect of porosity, standard deviation and deformation can be compensated to certain extent by the positive effect of the magnetic fluid lubricant in the case of negatively skewed roughness by choosing the rotational inertia and the aspect ratio, especially for suitable ratio of curvature parameters.

scholarly journals EFFECT OF SURFACE ROUGHNESS ON CHARACTERISTICS OF MAGNETIC FLUID BASED SQUEEZE FILM BETWEEN POROUS CIRCULAR PLATES

2020 ◽  
Vol 14 (1) ◽  
pp. 90-98
Author(s):  
P. L. Thakkar ◽  
H. C. Patel
Keyword(s):  
Surface Roughness ◽  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Type Equation ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Circular Plates ◽  
Load Carrying ◽  
Better Than ◽  
Effect Of Surface

The effect of surface roughness on characteristics of magnetic fluid based squeeze film between porous circular plates is hypothetically analysed. The pressure distribution is obtained by solving concern Reynolds type equation with suitable boundary conditions and the result is utilized to obtain load carrying capacity. It is concluded that the load carrying capacity increases with increasing magnetization, while load carrying capacity decreases due to the standard deviation. It is observed that the negatively skewed roughness and negative mean increase the load carrying capacity. It is also observed that the magnetic fluid lubricant improves the performance of a bearing system, thereby, suggesting that the performance of the bearing with magnetic fluid lubricant is better than the conventional lubricant.

Numerical investigation of squeeze film lubrication on bioinspired hexagonal patterned surface

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Binbin Su ◽  
Xianghe Zou ◽  
Lirong Huang
Keyword(s):  
Flow Rate ◽  
Carrying Capacity ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Two Dimensional ◽  
Working Mechanism ◽  
Content Type ◽  
Patterned Surface ◽  
Load Carrying ◽  
Film Lubrication

Purpose This paper aims to investigate the squeeze film lubrication properties of hexagonal patterned surface inspired by the epidermis structure of tree frog’s toe pad and numerically explore the working mechanism of hexagonal micropillar during the acquisition process of high adhesive and friction for wet contacts. Design/methodology/approach A two-dimensional elastohydrodynamic numerical model is employed for the squeezing contacts. The pressure distribution, load carrying capacity and liquid flow rate of the squeeze film are obtained through a simultaneous solution of the two-dimensional Reynolds equation and elasticity deformation equations. Findings Higher pressure is found to be longitudinally distributed across individual hexagonal pillar, with pressure peak emerging at the center of hexagonal pillar. Expanding the area density and shrinking the channel depth or initial film thickness will improve the magnitude of squeezing pressure. Relatively lower pressure is generated inside interconnected channels, which reduces the load carrying capacity of the squeeze film. Meanwhile, the introduction of microchannel is revealed to downscale the total mass flow rate of squeezing contacts. Originality/value This paper provides a good proof for the working mechanism of surface microstructures during the acquisition process of high adhesive and friction for wet contacts.

scholarly journals Performance of a Ferrofluid Based Rough Parallel Plate Slider Bearing: A Comparison of Three Magnetic Fluid Flow Models

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Jimit R. Patel ◽  
G. M. Deheri
Keyword(s):  
Fluid Flow ◽  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Parallel Plate ◽  
Type Equation ◽  
Load Carrying Capacity ◽  
Slider Bearing ◽  
Flow Models ◽  
Load Carrying ◽  
Long Life

Efforts have been made to present a comparison of all the three magnetic fluid flow models (Neuringer-Rosensweig model, Shliomis model, and Jenkins model) so far as the performance of a magnetic fluid based parallel plate rough slider bearing is concerned. The stochastic model of Christensen and Tonder is adopted for the evaluation of effect of transverse surface roughness. The stochastically averaged Reynolds-type equation is solved with suitable boundary conditions to obtain the pressure distribution resulting in the calculation of load carrying capacity. The graphical results establish that for a bearing’s long life period the Shliomis model may be employed for higher loads. However, for lower to moderate loads, the Neuringer-Rosensweig model may be deployed.

scholarly journals Influence of viscosity variation on ferrofluid based long bearing

2022 ◽  
Vol 3 (1) ◽  
pp. 37-45
Author(s):  
Jimit Patel ◽  
◽  
G. M. Deheri ◽  
Keyword(s):  
Fluid Flow ◽  
Theoretical Analysis ◽  
Pressure Distribution ◽  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Type Equation ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Viscosity Variation

This paper deals with a theoretical analysis on the effect of viscosity variation on a ferrofluid based long bearing. The model of Tipei considering viscosity variation is deployed here. The magnetic fluid flow is governed by Neuringer-Rosensweig model. The pressure distribution is obtained after solving the associated Reynolds type equation, which gives the load carrying capacity. The computed results indicate that the increased load carrying capacity owing to magnetization gets negligible help from the effect of viscosity variation.

scholarly journals Performance of Magnetic-Fluid-Based Squeeze Film between Longitudinally Rough Elliptical Plates

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
P. I. Andharia ◽  
G. M. Deheri
Keyword(s):  
Magnetic Fluid ◽  
Carrying Capacity ◽  
Random Variable ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Axially Symmetric ◽  
Load Carrying ◽  
Mean Variance ◽  
Bearing System ◽  
Oblique Magnetic Field

An attempt has been made to analyze the performance of a magnetic fluid-based-squeeze film between longitudinally rough elliptical plates. A magnetic fluid is used as a lubricant while axially symmetric flow of the magnetic fluid between the elliptical plates is taken into consideration under an oblique magnetic field. Bearing surfaces are assumed to be longitudinally rough. The roughness of the bearing surface is characterized by stochastic random variable with nonzero mean, variance, and skewness. The associated averaged Reynolds’ equation is solved with appropriate boundary conditions in dimensionless form to obtain the pressure distribution leading to the calculation of the load-carrying capacity. The results are presented graphically. It is clearly seen that the magnetic fluid lubricant improves the performance of the bearing system. It is interesting to note that the increased load carrying capacity due to magnetic fluid lubricant gets considerably increased due to the combined effect of standard deviation and negatively skewed roughness. This performance is further enhanced especially when negative variance is involved. This paper makes it clear that the aspect ratio plays a prominent role in improving the performance of the bearing system. Besides, the bearing can support a load even when there is no flow.

Investigation of Combined Effects of Rotational Inertia and Viscosity–Pressure Dependency on the Squeeze Film Characteristics of Parallel Annular Plates Lubricated by Couple Stress Fluid

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. Daliri ◽  
D. Jalali-Vahid
Keyword(s):  
Couple Stress ◽  
Squeeze Film ◽  
Rotational Inertia ◽  
Combined Effects ◽  
Load Carrying Capacity ◽  
Annular Plates ◽  
Pressure Dependency ◽  
Load Carrying ◽  
Viscosity Variation ◽  
Film Characteristics

This study presents combined effects of couple stress fluids and rotational inertia together with considering lubricant viscosity variation with pressure in squeeze film characteristics of parallel annular plates. Squeeze film characteristics are obtained by combined solution of modified Reynolds equation and Stoke's microcontinuum for couple stress fluids with consideration of viscosity variation with pressure. Various cases of couple stress, inertial, and noninertial characteristics with isoviscous and piezoviscous contributions are investigated. The pressure distribution and load-carrying capacity for lubricant film are obtained in a closed form, using a small perturbation method. Furthermore, numerical solution of the film height versus response time is calculated employing the fourth-order Runge–Kutta method. The result shows that the combined effects of couple stresses and viscosity–pressure dependency improve the load-carrying capacity and lengthen the response time, as compared to the classical Newtonian lubricant with constant viscosity. However, increasing rotational inertia parameter decreases squeeze film characteristics.

Effect of surface roughness on magneto-hydrodynamic squeeze-film characteristics between a sphere and a porous plane surface

2014 ◽  
Vol 66 (3) ◽  
pp. 365-372 ◽  
Author(s):  
Neminath Bhujappa Naduvinamani ◽  
Mareppa Rajashekar
Keyword(s):  
Surface Roughness ◽  
Response Time ◽  
Carrying Capacity ◽  
Hydrodynamic Lubrication ◽  
Plane Surface ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Content Type ◽  
Load Carrying ◽  
Film Characteristics

Purpose – The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous plane surface, which have not been studied so far. Design/methodology/approach – The analytical model takes into account the effect of porosity by assuming that the flow in the porous matrix obeys modified Darcy's law. The stochastic MHD Reynold's type equation is derived by using the Christensen's stochastic method developed for hydrodynamic lubrication of rough surfaces. Two types of one-dimensional surface roughness (radial and azimuthal) patterns are considered. Findings – The expressions for the mean MHD squeeze-film pressure and mean load-carrying capacity are obtained numerically. The results are shown graphically for selected representative parametric values. It is found that the response time increases significantly for the MHD case as compared to the corresponding non-conducting lubricants. The effect of roughness parameter is to increase/decrease the load-carrying capacity and the response time for azimuthal/radial roughness patterns as compared to the smooth case. Also, the effect of porous parameter is to decrease the load-carrying capacity and response time as compared to the solid case. Originality/value – In this paper, an attempt has been made to analyse the combined effects of surface roughness and permeability on the MHD squeeze-film characteristics between a sphere and a plane surface.

scholarly journals Couple Stress Squeeze Films with VPD in a Curved Circular Geometry

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Vimala Ponnuswamy ◽  
Sumathi Govindaraj
Keyword(s):  
Carrying Capacity ◽  
Couple Stress ◽  
Numerical Solutions ◽  
Perturbation Technique ◽  
Type Equation ◽  
Squeeze Film ◽  
Load Carrying Capacity ◽  
Film Pressure ◽  
Sinusoidal Motion ◽  
Load Carrying

The problem of couple stress squeeze films considering viscosity pressure dependence (VPD) has been analysed in a curved circular geometry. Using Stokes microcontinuum theory and the Barus formula, the Reynolds type equation has been derived. The approximate analytical expressions for the squeeze film pressure and load carrying capacity are obtained using a perturbation technique. The numerical solutions for the squeeze film pressure and load carrying capacity are presented for the sinusoidal motion of the upper curved disk, assuming an exponential form for the curvature. The effects of curvature, the non-Newtonian couple stresses, and VPD and their combined effects are investigated through the squeeze film pressure and the load carrying capacity of the squeeze film.

Analysis of a circular journal bearing lubricated with micropolar fluids including EHD effects

2014 ◽  
Vol 66 (2) ◽  
pp. 168-173 ◽  
Author(s):  
Boualem Chetti
Keyword(s):  
Elastic Deformation ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Newtonian Fluids ◽  
Load Carrying Capacity ◽  
Micropolar Fluids ◽  
Content Type ◽  
Load Carrying ◽  
Modified Reynolds Equation

Purpose – The performance of finite circular journal bearing lubricated with micropolar fluids taking into account the elastic deformation of the bearing liner is presented. The paper aims to discuss these issues. Design/methodology/approach – The modified Reynolds equation is obtained using the micropolar lubrication theory. The solution of the modified Reynolds equation is determined using finite difference technique. The static characteristics in terms of load-carrying capacity, attitude angle, side leakage and friction coefficient for micropolar and Newtonian fluids are determined for various values of eccentricity ratio and different values of elastic coefficient. Findings – Compared with Newtonian fluids, the micropolar fluids produce an increase in the load-carrying capacity and a reduction in the attitude angle, the friction factor and side leakage for both the rigid and deformable bearings. Originality/value – It is concluded that the influence of elastic deformation on the bearing characteristics lubricated with micropolar fluids is significantly apparent compared with bearing lubricated with Newtonian fluids.

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