Dynamic Analysis of Finite Half-Elliptical Pressure Dam Bearings with Rotor Flexibility Effects

Abstract

This paper presents an analytical study of dynamic characteristics of half-elliptical pressure dam bearings. One half (either upper or lower) of these bearings is elliptical, while the other half is circular. A step or pressure dam is cut in the upper half bearing surface. The lower half bearing surface is provided with a deep groove or relief-track.

These bearings have been analyzed by the finite-element method. The results have been computed for dimensionless rotor flexibilities of 0.0, 0.5, 1.0, 2.0, and 4.0. Dynamic characteristics such as stiffness and damping coefficients, and stability threshold speed are presented in the form of graphs.

It has been determined that half-elliptical pressure dam bearings are superior to circular pressure dam bearings in stability for bearings having same design parameters. Both these half-elliptical pressure dam bearings have almost identical dynamic characteristics. Rotor flexibility adversely affects the stability of these bearings and its effect is pronounced at high Sommerfeld numbers.

Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984

Notes

Presented as an American Society of Lubrication Engineers paper at the ASLE/ASME Lubrication Conference in San Diego, California, October 22–24, 1984