Equilibrium of a Journal Bearing: A Simplified CFD-Analytical Coupled Approach

Abstract

Journal bearings are historically designed using the half-Sommerfeld theory. The semi-analytical solution of the continuity and momentum conservation equations is used as the starting point. Possible negative values of the pressure were substituted with the ambient pressure. This hypothesis provides acceptable results, even if for a better understanding of the phenomena cavitation effects should be considered and modelled numerically. The authors have already proved the capability to achieve very accurate results with the Kunz cavitation model. The numerical results were validated in terms of pressure distribution with experimental data coming from different setups. In this paper, a simplified CFD-analytical coupled approach for the calculation of the equilibrium position and its trajectory of the journal is shown.

A Comprehensive Numerical Study of a Wedge-Shaped Textured Convergent Oil Film Gap

“…In [26], the Merkle [27] cavitation model, among others, for a journal bearing was compared with the measured results in [28] and yielded favorable outcomes. This cavitation algorithm is also used in this study and presented in Equations ( 4)- (9).…”

Vibration monitoring of a hydroelectric power generation unit: Improved indicators of rotor health based on orbital analysis

“…In particular, using the relaxation method [9], derivatives are replaced by finite difference approximations leading to a linear system of equations which can be solved considering Full-Sommerfeld periodic boundary conditions (i.e., null initial and final pressures). Nevertheless, the Full-Sommerfeld solution does not consider the occurrence of cavitation, so that the Half-Sommerfeld approach will be used in this simplified model (historically accepted journal bearing design approximation [10]).…”