Steady-State Experiments on Rotating Externally Pressurized Air-Lubricated Journal Bearings

Abstract

Experimental load, stiffness and attitude angle data for a pair of 2 1/2-in-dia, 3 3/4-in-long externally pressurized air journal bearings are compared with two small eccentricity perturbation theories. Results show that load capacity is generally less than predicted by either theory, however, agreement with the small eccentricity pressure perturbation theory is better than with the linearized PH theory. Self-acting effects from journal rotation are greatest at the higher eccentricity ratios and lower supply pressures. Attitude angles vary with shaft speed as predicted by theory but are generally larger in magnitude. Measured air mass flow through the bearings agreed well with calculated values. Results were obtained for speeds up to 25,000 rpm and radial loads varied up to 20.2 psi.