Non-linear transient analysis of multiple axial groove water-lubricated journal bearings

Abstract

The stability characteristics of water-lubricated journal bearings having multiple axial grooves are studied theoretically. These bearings can use the process fluid as the lubricant as in the case of feed water pumps. The process fluid (water) is fed from one end of the bearing, through the multiple axial grooves (groove angles may vary). A non-linear analysis of a rigid rotor supported on journal bearings under unidirectional constant load, unidirectional periodic load, and variable rotating load is carried out. The time-dependent Reynolds equation in two-dimension for incompressible fluid is solved numerically by the finite-difference method with a successive over relaxation scheme satisfying the Jakobsson—Floberg—Olsson boundary conditions, to obtain the hydrodynamic forces. Using these forces, the equations of motion are solved by the fourth-order Runge—Kutta method to predict the transient behaviour of the rotor. The analysis gives the orbital trajectory within the clearance circle.