On the ferrofluid lubricated squeeze film characteristics between a rotating sphere and a radially rough plate

Ferrofluid lubricated squeeze film bearing design system formed by a rotating upper spherical surface and a radially rough lower flat plate considering variable magnetic field, which is oblique to the lower plate, have been analyzed. The variable magnetic field is important because of its advantage of generating maximum field at the required active contact zone. The problem is motivated because squeeze film behaviour is widely observed in many industrial applications like in machine tools, gears, rolling elements, hydraulic systems, engines, clutch plates, force pendulum apparatus, etc. Moreover, the squeeze film behaviour is also observed in skeletal joints of human body. On the basis of ferrohydrodynamic theory and Christensen’s stochastic theory for hydrodynamic lubrication of rough surfaces, the modified Reynolds equation is derived and expressions for squeeze film characteristics are obtained which are calculated numerically and interpreted. While deriving Reynolds equation effects of various parameters like rotation, width of the nominal minimum film thickness and squeeze velocity are also considered.