Analytical Evaluation of the Static and Dynamic Characteristics of Three Lobe Journal Bearings With Finite Length

Abstract

The threelobe bearings widely used in rotating machinery follow the design data evaluated using numerical methods for the solution of the Reynolds equation. This paper defines exact and approximate analytical solutions of the Reynolds equation for the case of threelobe bearings with finite length. Dynamic characteristics are provided analytically with closedform expressions for laminar regimes of operation, using an approximate analytical solution that proves to be reliable and of low cost of evaluation time. The results for eccentricity ratio, equilibrium locus, stiffness and damping coefficients are presented for a range of Sommerfeld number and different cases of load orientation and compared with theoretical and experimental data from the literature.