Foil Bearing lubricated with contaminated air : a numerical analysis

Abstract

This paper presents an original theoretical investigation of the steady-state and dynamic performance characteristics of foil journal bearings lubricated with contaminated air taking into account couple-stresses due to the presence of small amount of natural or artificial pollutant substances. The substance can be solid particles (e.g. dust, ash, pollen, smoke) liquid droplets, or gases. To determine the aerodynamic pressure and the power loss, the governing modified Reynolds’ equation, and the viscous dissipation term appearing on the RHS of the modified energy equation are derived using the V. K. Stokes micro-continuum theory. According to the obtained results, the effects of couple stresses on the steady-state and dynamic behavior of foil self-acting gas bearings are significant and cannot be overlooked. The results also show that the dynamic deformation of the bump foil should be included in calculating the dynamic performance characteristics of foil journal bearings.