1989 Volume 32 Issue 1 Pages 91-99
The present study is a theoretical analysis to evaluate the static and dynamic characteristics of oil-filled porous journal bearings with anisotropic permeability. The analytical models are the porous bearings whose permeabilities are lower in one direction than in the other two directions. Considering anisotropic permeability, the Reynolds equation for the oil film is modified to include a so-called filter term and the effect of tangential velocity slip, and the pressure equation for the porous medium is obtained from Darcy's law and continuity equation. These equations are applied to the system and are numerically solved. By comparison of anisotropic types with the isotropic type in which permeability is equal to the higher one of the anisotropic types, it is found that anisotropic types have a higher load carrying capacity and a lower total side leakage flow. Furthermore, anisotropic ones have larger oil film coefficients, in which the cross-coupled term Kxy is larger in magnitude, and higher stability threshold speed (oneset speed of half-speed whirl).