THE EFFECTS OF COUPLESTRESS ON THE PERFORMANCE OF SQUEEZE FILM BETWEEN ELLIPTICAL PLATES LUBRICATED WITH A FERROFLUID (original) (raw)
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This paper focus to study the couple stress effects with rotational inertia forces on ferrofluid based squeeze film between porous circular plates. Based upon Morgan-Cameron approximation, Stokes couple stress fluid model and Shliomis ferromagnetic fluid model, the squeeze film attributes for porous circular plates are achieved. From the results achieved and discussed, the impacts of rotating fluid inertia and permeability of the upper plate lead to reduce the load carrying capacity and a shorter the squeezing time as compared to the non-rotating and non-porous bearing case. The squeeze film characteristics between porous circular plates can be improved by considering rotational fluid inertia and Non-Newtonian ferrofluid as lubricant.
Performance of Magnetic-Fluid-Based Squeeze Film between Longitudinally Rough Elliptical Plates
ISRN Tribology, 2013
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 combine...
Advances in Tribology, 2015
The combined effect of surface roughness and magnetic field on the performance characteristic of the circular plates lubricated with conducting couplestress fluid (CCSF) has been studied. On the basis of the Christensen Stochastic model, the generalized stochastic Reynold’s equation is derived. Modified equations for the nondimensional pressure, load load-carrying capacity, and squeeze film time are derived. The results are presented both numerically and graphically and compared with conducting smooth surface case. It is observed that the surface roughness effects are more pronounced for couplestresses as compared to nonconducting Newtonian fluid (NCNF) in the presence of magnetic field.
Elsevier, 2021
In this paper, we investigated the combined effect of variable-viscosity, surface roughness, couple stress fluid, velocity-slip, and ferrofluid lubricant on the fluid-film characteristics of an infinitely wide rectangular plate squeeze-film bearing. The variable-viscosity is obtained using the Barus formula and the lubricant becomes non-Newtonian due to the combination of the couple-stress fluid and the ferrofluid lubricant. The Modified Reynolds equation is used to solve the pressure distribution, where an external magnetic field produces a body force in the lubricating system. We calculated the pressure distribution and the load-carrying characteristics of the squeeze film bearing. The results indicate that the slipvelocity enhances the pressure distribution and the load-carrying capacity of the bearing. For a combination of slip-velocity and Magnetic parameters, the load and pressure distribution are greatly enhanced.
2017
Efforts have been made to analyze the combined effect of surface roughness and slip velocity on the ferrofluid squeeze film in double layered porous circular plates. The magnetic fluid flow is governed by Neuringer – Roseinweig model while the stochastic modelling of Christensen and Tonder has been adopted to evaluate the effect of transverse roughness. The associated stochastically averaged Reynolds' type equation is solved to obtain the pressure distribution leading to the calculation of load carrying capacity. The results presented in the graphical forms establish that the magnetization offers a limited scope in containing the adverse effect of roughness, porosity, and slip velocity. However, the situation improves when negatively skewed roughness occurs. But for any type of improvement in the bearing performance the slip has to be kept at reduced level even if variance (-ve) is involved.
Acta Polytechnica
This article makes an effort to present a comparative study on the performance of a Shliomis model-based ferrofluid (FF) lubrication of a porous squeeze film in curved annular plates taking slip velocity into account. The modified Darcy’s law has been adopted to find the impact of the doublelayered porosity, while the slip velocity effect has been calculated according to Beavers and Joseph’s slip conditions. The modified Reynolds equation for the double-layered bearing system is solved to compute a dimensionless pressure profile and load-bearing capacity (LBC). The graphical results of the study reveal that the LBC increases in the case of magnetization, volume concentration and upper plate’s curvature parameter while it decreases with other parameters for both the film thickness profile. A comparative study suggests that the exponential film thickness profile is more suitable to enhance LBC for the annular plates lubricated by ferrofluid, including the presence of a slip. The study...
An endeavor has been made to study and analyze the effect of slip velocity on the performance of a squeeze film in porous rough infinitely long parallel plates in the presence of a magnetic fluid lubricant. The Neuringer-Rosensweig model governs the fluid flow while the velocity slip is modeled by the method of Beavers and Joseph. A stochastic random variable with nonzero mean, variance, and skewness characterizes the random roughness of the bearing surfaces. With the adding of suitable boundary conditions, the associated stochastically averaged Reynolds' equation is solved to obtain the fluid pressure, in turn, which results in the calculation of the load-carrying capacity. It is found that although the bearing suffers owing to transverse surface roughness, the performance of the bearing system can be improved to some extent by the positive effect of magnetization, considering the slip parameter at the minimum, at least in the case of negatively-skewed roughness. A comparison of this study with some established investigations indicates that the reduction of load-carrying capacity due to porosity and slip velocity is comparatively less here especially, when negative variance occurs.Of course, in augmenting the performance of the bearing system, the aspect ratio plays a central role even if the slip parameter is at the minimum. This article offers the suggestions that for a better performance of the bearing system, the slip velocity should be minimized, even if the magnetic strength has been chosen suitably. It is established that the bearing can support a load even in the absence of flow, unlike the case of a conventional lubricant.