Effect of Surface Roughness on the Behavior of a Magnetic Fluid-based Squeeze Film between Circular Plates with Porous Matrix of Variable Thickness

Abstract

An endeavor has been made to investigate the performance of a magnetic fluid based squeeze film between rough circular plates while the upper plate has a porous facing of variable porous matrix thickness. The bearing surfaces are transversely rough. The random roughness of the bearing surfaces is characterized by a random variable with non- zero mean, variance and skewness. The associated Reynolds' equation is stochastically averaged with respect to the random roughness parameter and is solved with appropriate boundary conditions. The results for bearing performance characteristics such as pressure, load carrying capacity and response time for different values of mean, standard deviation and measure of symmetry are numerically computed and presented graphically. First of all it is observed that these performance characteristics increase with the increasing magnetization parameter thereby, suggesting that the performance of the bearing with magnetic fluid lubricant is better than that with the conventional lubricant. It is noticed that the bearing suffers owing to transverse surface roughness. However, the negatively skewed roughness tends to increase the load carrying capacity. Moreover, there is a very significant observation that with a proper selection of the thickness ratio parameter a magnetic fluid based squeeze film bearing with variable porous matrix thickness in the case of negatively skewed roughness can be made to perform considerably better than that of a conventional porous bearing with an uniform porous matrix thickness working with a conventional lubricant. In addition, this article makes it clear that by choosing properly the thickness ratio parameter and the strength of the magnetic field, the adverse impact induced by roughness on the bearing system can be minimized in the case of negatively