G.M. Deheri, R.M. Patel and Nikhilkumar D. Abhangi
This paper aims to improve upon the performance of magnetic fluid‐based squeeze film between transversely rough curved annular plates by embarking on a comparative study of the…
Abstract
Purpose
This paper aims to improve upon the performance of magnetic fluid‐based squeeze film between transversely rough curved annular plates by embarking on a comparative study of the geometrical structure of the curved annular plates.
Design/methodology/approach
The objectives are met by mathematically modeling a magnetic fluid‐based squeeze film between transversely rough curved annular plates. The standard method is to solve the associated Reynolds' equation with appropriate boundary conditions by describing the random roughness through a stochastic random variable with non‐zero mean, variance and skewness. Results for bearing performance characteristics such as pressure distribution and load‐carrying capacity are numerically computed. In order to analyze the quantitative effect of the roughness, different geometrical structures of surfaces have been considered and the results are compared.
Findings
Certainly, the performance of the bearing with the magnetic fluid lubricant is comparatively better than the conventional lubricant. The findings indicate that although the effect of roughness is adverse in general, the adverse effect introduced by roughness and aspect ratio can be compensated for, to a considerable extent, by the positive effect of magnetization parameter in the case of negatively skewed roughness by choosing the curvature parameters properly.
Practical implications
From the industry point of view, this investigation will be definitely useful for improving the performance of the squeeze film based on magnetic fluid between transversely rough curved annular plates by minimizing the effect of roughness. Furthermore, it offers an additional degree of freedom from a design point of view in the form of the geometrical structure of the surfaces.
Originality/value
The paper presents significant information as it compares shapes and offers suggestions for the best improved performance from a bearing's longevity point of view. This study presents an approach for the enhanced performance of the magnetic fluid‐based squeeze film between transversely rough curved annular plates.
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Paresh Indubhai Andharia and Gunamani Deheri
The paper aims to improve upon the performance of a squeeze film formed by a magnetic fluid between longitudinally rough conical plates.
Abstract
Purpose
The paper aims to improve upon the performance of a squeeze film formed by a magnetic fluid between longitudinally rough conical plates.
Design/methodology/approach
The objectives are achieved by mathematically modeling a magnetic fluid‐based squeeze film between longitudinally rough conical plates. The roughness of the bearing surface is modeled by a stochastic random variable with non‐zero mean, variance and skewness. The standard approach is to solve associated Reynold's equation which is stochastically averaged with respect to the random roughness parameter. The scope of this paper is the industrial applications with regard to enhanced performance of the bearing system.
Findings
The findings indicate that the performance of the bearing gets enhanced due to negatively skewed roughness. It is also noticed that the standard deviation increases the load carrying capacity which is unlike the case of transverse surface roughness. Further, this paper suggests that there exist considerable scopes for enhancing the performance of the longitudinally rough bearing system by choosing a suitable combination of the magnetization parameter and the semi‐vertical angle of the cone.
Practical implications
From the industry point of view, this investigation will be certainly useful for improving the performance of a magnetic fluid‐based squeeze film between longitudinally rough conical plates.
Originality/value
The paper presents the improved performance of a squeeze film formed by a magnetic fluid between longitudinally rough conical plates and thereby extending the life period of the bearing system.
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Rakesh M. Patel and G.M. Deheri
This paper aims to improve upon the performance of squeeze film between porous conical plates.
Abstract
Purpose
This paper aims to improve upon the performance of squeeze film between porous conical plates.
Design/methodology/approach
The objectives are achieved by mathematically modeling a magnetic fluid based squeeze film between porous conical plates. The standard approach is to solve associated Reynolds' equation with appropriate boundary conditions. The scope of this paper is the industrial applications with regard to enhanced performance of the bearing system.
Findings
Definitely the performance of the bearing with the magnetic fluid lubricant is relatively better than the conventional lubricant. The findings indicate that the negative effect induced by the porosity can be neutralized by the positive effect caused by the magnetization parameter. Further, this paper suggests that there is scope for enhancing the performance of the bearing system by choosing a suitable combination of the magnetization parameter and semi‐vertical angle.
Practical implications
From the industry point of view this investigation will be certainly useful for improving the performance of the squeeze film between porous conical plates.
Originality/value
This paper presents the augmented performance of the squeeze film between porous conical plates and thereby extending even the life period of the machines.
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Mukesh E. Shimpi and Gunamani Deheri
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…
Abstract
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.
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Efforts have been directed to study the magnetic fluid based squeeze film behaviour between rotating porous circular plates with a concentric pocket. The porous housing is…
Abstract
Efforts have been directed to study the magnetic fluid based squeeze film behaviour between rotating porous circular plates with a concentric pocket. The porous housing is considered to be elastically negligibly deformable with its contact surface rough. The stochastic film thickness characterizing the roughness is assumed to be asymmetric with non‐zero mean and variance. Expressions for pressure distribution, load carrying capacity and response time are obtained in closed form. These expressions are numerically computed and the results are presented graphically as well as in tabular form.
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Devender, Paras Ram and Kushal Sharma
The present article aims to investigate the squeeze effects on hematite suspension-based curved annular plates with Rosensweig’s viscosity and Kozeny–Carman’s porous structure…
Abstract
Purpose
The present article aims to investigate the squeeze effects on hematite suspension-based curved annular plates with Rosensweig’s viscosity and Kozeny–Carman’s porous structure under the variable strong magnetic field and slip in the Shliomis model. The variable magnetic field is utilised to retain all magnetic elements within the model. The aforementioned mechanism would have the benefit of generating a maximal field at the system’s required active contact zone.
Design/methodology/approach
The Kozeny–Carman globular sphere model is used for porous facing. Rosensweig’s extension of Einstein’s viscosity is taken into consideration to enhance the fluid’s viscosity, and Beavers and Joseph’s slip boundary conditions are employed to assess the slip effect.
Findings
The pressure and lifting force under squeezing are computed through modification of the Reynolds equation with the addition of Kozeny–Carman’s model-based porosity, Rosensweig’s viscosity, slip and varying magnetic field. The obtained results for the lifting force are very encouraging and have been compared with Einstein’s viscosity-based model.
Originality/value
Researchers so far have carried out problems on lubrication of various sliders considering Einstein’s viscosity only, whereas in our problem, Rosensweig’s viscosity has been taken along with Kozeny–Carman’s porous structure model.
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G.M. Deheri, P.I. Andharia and R.M. Patel
The effect of longitudinal surface roughness on the behaviour of slider bearing with squeeze film formed by a magnetic fluid has been analysed. The roughness of the bearing…
Abstract
The effect of longitudinal surface roughness on the behaviour of slider bearing with squeeze film formed by a magnetic fluid has been analysed. The roughness of the bearing surface is modelled by stochastic random variable with non‐zero mean, variance and skewness. The concerned Reynolds' equation is stochastically averaged with respect to the random roughness parameter. Results for bearing performance characteristics such as load carrying capacity of the bearing, centre of pressure, frictional force and coefficient of friction for different values of α (mean), σ (standard deviation) and ε (measure of symmetry) are numerically computed. In order to investigate the quantitative effect of roughness on the performance characteristics, four shapes namely; plane slider, exponential slider, hyperbolic slider and secant slider for the lubricant film are considered. The results are presented in tabular form as well as graphically. It is observed that the bearing performance is significantly affected by all the three parameters characterizing the surface roughness.
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Guotao Zhang, Yanguo Yin, Lu Xue, Guoqian Zhu and Ming Tian
The purpose of this paper is to discuss the combined effects of the deterministic surface roughness and porous structure on the lubrication property of the multi-layer bearing.
Abstract
Purpose
The purpose of this paper is to discuss the combined effects of the deterministic surface roughness and porous structure on the lubrication property of the multi-layer bearing.
Design/methodology/approach
Digital filtering technique and Kozeny-Carman equation are used to simulate the random Gauss surface and the internal pore structure of the porous bearing, respectively. Effects of surface morphology, structure and pores on the lubrication property are discussed by using the finite difference method.
Findings
Results show that the lubrication performance of the multi-layer bearing increased with the increase of the surface roughness. Also, the transverse surface is better than that of the longitudinal surface. Moreover, lubricating property is getting worse with the increase of the height of each layer and the porosity. The lower permeability surface is beneficial to improve the lubrication performance when the total porosity is certain.
Originality/value
The effect of the Gauss roughness parameters on the detail of lubrication performance are analysed, such as the migration of the oil film rupture point position, the expansion of the pressure distribution region and the fluctuation of the pressure distribution curve with the roughness parameters. The combined effects of surface roughness, multi-layer structure and the internal pore parameters on the hydrodynamic behaviours of multi-layer porous bearing are analysed. This work is beneficial for the analysis of the tribological property and the structural design of multi-layer bearing.
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Himanshu Patel, Gunamani M. Deheri and Rakesh M. Patel
The purpose of this paper is to study and analyze the effect of roughness and magnetic fluid lubricant on the performance of the squeeze film formed when the upper plate with a…
Abstract
Purpose
The purpose of this paper is to study and analyze the effect of roughness and magnetic fluid lubricant on the performance of the squeeze film formed when the upper plate with a porous facing approaches an impermeable and flat lower plate by considering the rotation of the plates.
Design/methodology/approach
The roughness of the bearing surface is modeled by a stochastic random variable with non‐zero mean, variance and skewness. The associated Reynolds' equation is stochastically averaged with respect to the random roughness parameter. Results for bearing performance characteristics such as load‐carrying capacity and response time for various values of mean, standard deviation and measure of symmetry are numerically computed. The results are presented graphically as well as in tabular form.
Findings
It is observed that the bearing suffers owing to the transverse surface roughness. However, negatively skewed roughness may enhance the performance of the bearing system for suitable values of variance. It is also seen that rotation decreases the load‐carrying capacity but it has marginal influence in the presence of the magnetic fluid. Further, the performance of the bearing system registers a steady improvement with the increasing values of the magnetization parameter. In addition, the response time follows the trends of the load‐carrying capacity.
Originality/value
The originality of the paper lies in the fact that the roughness must be accounted for while designing the bearing system, even though a suitable rotation ratio parameter is chosen in the presence of a strong magnetic fluid. Of course, the best performance of the bearing system is registered in the case of negatively skewed roughness.
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P.I. Andharia, J.L. Gupta and G.M. Deheri
Efforts have been made to study the optimum film profile for a longitudinally rough slider bearing. The roughness of the bearing surface is modelled by stochastic random variable…
Abstract
Efforts have been made to study the optimum film profile for a longitudinally rough slider bearing. The roughness of the bearing surface is modelled by stochastic random variable with non‐zero mean, variance and skewness. The governing differential equation for lubricant pressure is the Reynolds equation which is stochastically averaged with respect to the random roughness parameter. The method of infinitesimal is used to determine the optimum lubricant film profile. Results for the step location, step height ratio and the bearing performance characteristics, such as load carrying capacity of the bearing, centre of pressure, frictional force and coefficient of friction for different values of α, σ and ε, are numerically computed and tabulated. It is observed that the parameters α, σ and ε characterizing the surface roughness of the bearing affect the bearing performance characteristics significantly.