Rakesh M. Patel

Magnetic Fluid Based Squeeze Film Behavior between Transversely Rough Curved Plates

An endeavor has been made to analyze the magnetic fluid based squeeze film behavior between two transversely rough curved plates, when the curved upper plate approaches the stationary curved lower plate. The lubricant used is a magnetic fluid in the presence of an external magnetic field oblique to the radial axis. The roughness of the bearing surface is modeled by a stochastic random variable with nonzero mean, variance and skewness. The associated Reynolds equation is solved with appropriate boundary conditions to obtain the pressure distribution, which is, then used to get the expression for load carrying capacity. To present a comparative study we consider the curvature of exponential form, hyperbolic form and secant form to represent the film thickness. The results are presented graphically. It is found that the load carrying capacity increases with increasing magnetization. It is seen that the bearing suffers in general, owing to the surface roughness. It is observed that negatively skewed roughness increases the load carrying capacity. The adverse effect induced by the standard deviation, positive variance and positive skewness can be compensated up to certain extent by the magnetization parameter taking an appropriate choice of curvature parameters.

Performance of a Magnetic Fluid Based Squeeze Film Between Infinitely Long Rough Porous Rectangular Plates

An attempt has been made to discuss the performance of a magnetic fluid based squeeze film between porous infinitely long transversely rough rectangular plates. A magnetic fluid is used as a lubricant and the external magnetic field is oblique to the lower plate. The roughness of the bearing surfaces is characterized by a stochastic random variable with non-zero mean, variance and skewness. The associated Reynolds’ equation is solved with suitable boundary conditions to obtain the pressure distribution in turn, which is used to get the expression for load carrying capacity resulting in the calculation of response time. The graphical representation tends to suggest that the bearing system registers an enhanced performance as compared to that of a bearing system dealing with a conventional lubricant. In fact, the pressure, load carrying capacity and response time increase with increasing magnetization parameter. It is noticed that the bearing suffers in general due to transverse roughness. However, the present study reveals that the negatively skewed roughness improves the performance of the bearing system. In addition, it is observed that the aspect ratio significantly affects the performance of the bearing system. Besides, the present study indicates that although the combined negative influence of the porosity, standard deviation and the aspect ratio dominates the positive effect of the magnetization parameter, there exists some scopes for improving the performance of the bearing system by choosing a suitable combination of the magnetization parameter and the aspect ratio in the case of negatively skewed roughness because even the load carrying capacity increases due to negative variance. This article reveals that the roughness must be given due consideration while designing the bearing system even though there is the presence of a strong magnetic field.