Static and Dynamic Characteristics of Porous Journal Bearings with Nonuniform Permeability

Abstract

The present study is a theoretical analysis to evaluate the static and dynamic characteristics of oil-filled porous journal bearings with nonuniform permeability. Three types of nonuniform distributions of permeability are analyzed. For the first type, the permeability of the inside is lower than that of the outside. For the second type, the permeability of the loaded part is lower than that of the unloaded part. For the third type, the permeability of the bearing ends is lower than that of the middle. It is found that all nonuniform type bearings have a higher load carrying capacity, lower total side leakage flow, larger oil film coefficients, and higher stability threshold speed compared with the corresponding values of uniform type bearings, in which permeability is equal to the higher of nonuniform type bearings. Furthermore, the second nonuniform type has a higher load carrying capacity and a lower total side leakage flow than the other nonuniform types.