Rammohan S Pai

Stability of four-axial and six-axial grooved water-lubricated journal bearings under dynamic load

The non-linear transient analysis of water-lubricated journal bearings having four-axial and six-axial grooves is studied theoretically. The time-dependent form of the generalized Reynolds equation has been written as the governing equation in non-dimensional form. The Reynolds equation is solved by a finite-difference technique with a successive over-relaxation scheme, satisfying the Jakobsson—Floberg—Olsson boundary conditions. A non-linear time-transient analysis is carried out and the stability of journal is studied. The equations of motion are solved by the fourth-order Runge—Kutta method to obtain the eccentricity ratio, attitude angle, and their derivatives for the next time step.\newline\indent This study is performed for unidirectional constant load, unidirectional periodic load, and variable rotating load. The journal locus is plotted from the values of eccentricity ratio and attitude angle, and it helps in predicting the status of the system.

Stability Characteristics of a Tri-taper Journal Bearing: a Linearized Perturbation Approach

In this paper, the stability characteristics of a tri-taper journal bearing are analyzed theoretically. The time dependent form of Reynolds equation in two dimensions for incompressible fluid is solved numerically by finite difference method, satisfying the Reynolds boundary conditions. Dynamic coefficients are determined using the method of linearization of bearing reactions. A study with various ramp sizes and L/D ratios predicts that a bearing with higher ramp size and higher L/D ratio results in an increased mass parameter and improved stability margin of the bearing.