Thermohydrodynamic analysis of gas-lubricated self-acting journal bearings of finite length

This paper presents the thermohydrodynamic analysis of compressible gas-lubricated films in a finite width journal bearing. We consider a relation between pressure and density of the form P ρ^-n = constant, where n is the polytropic expansion exponent. Three cases are investigated: (1) isothermal (n=1), (2) reversible adiabatic (n=1.4) and (3) irreversible adiabatic (n is variable). The gas viscosity is also considered to be temperature dependent. The steady state operational performance characteristics of the bearing with length-to-diameter ratio of unity are obtained for the eccentricity ratio from 0.2 to 0.8, the bearing number from 1.0 to 10.0. Numerical results indicate that, as the bearing number and the eccentricity ratio increase, the load capacity, pressure distribution and maximum temperature all increase, while the friction coefficient and attitude angle decrease.