PERFORMANCE OF MAGNETIC FLUID BASED SQUEEZE FILM BETWEEN A CURVED POROUS CIRCULAR PLATE AND A FLAT CIRCULAR PLATE AND EFFECT OF SURFACE ROUGHNESS
M.Shimpi, G.Deheri (UDC: 624.073.2:620.191.35)
Abstract:
Efforts have been directed to study and analyze the squeeze film behavior between a curved rough porous circular plate and a flat rough porous circular plate under the presence of a magnetic fluid lubricant. The curved film thickness is described by a secant function. It is taken in to consideration that the external magnetic field is oblique to the lower plate. The bearing surfaces are assumed to be transversely rough. The random roughness of the bearing surfaces is characterized by a stochastic random variable with non-zero mean, variance and skewness. The concerned Reynolds equation governing the film pressure is averaged with respect to the random roughness parameter. The associated non-dimensional partial differential equation is solved with appropriate boundary conditions in dimensionless form to obtain the pressure distribution, in turn, which leads to the calculation of load carrying capacity. The computed results show that the performance of bearing system enhances considerably as compared to that of a bearing system working with a conventional lubricant as the magnetization increases the effective viscosity of the lubricant. The results tend to indicate that the bearing suffers due to transverse surface roughness, in general. Probably this may be due to the fact that the transverse surface roughness offers resistance to the motion of the lubricant. The effect of variance (negative) is considerably positive at least in the case of negatively skewed roughness as the load carrying capacity arises sharply. The combined effect of porosity and standard deviation is relatively adverse, in the sense that the already decreased load carrying capacity due to porosity gets further decreased owing to standard deviation. However, this investigation suggests some ways to mitigate this adverse effect.
