Effect of fluid inertia and texturing parameters on the stability of textured journal bearings: A non-linear time transient analysis

The stability of journal bearings is critical for ensuring the smooth operation and longevity of rotating machinery. While fluid inertia effects are often neglected in stability analyses, they become significant at high operating speeds and with low-viscosity lubricants. This study presents a non-linear transient analysis of textured journal bearings, explicitly incorporating fluid inertia effects, an area previously overlooked in stability studies. The novelty lies in evaluating the combined influence of texture geometry and fluid inertia on critical stability thresholds using non-linear transient analysis. Plain bearings, spherical protrusions, and dimple textures are investigated, and critical mass-parameters and whirl ratios are evaluated by varying the texture parameters across different eccentricity ratios. The influence of fluid inertia is assessed by varying the modified Reynolds number. The results from the study indicate that protrusion-textured bearings exhibit up to 30% higher critical mass-parameters than dimple textured and plain bearings, thus indicating superior stability compared to dimple textured and plain bearings. Stability is improved with increasing dimple aspect ratio and dimple area density but adversely affected with increasing non-dimensional clearance. Additionally, higher modified Reynolds numbers enhance the stability of lightly loaded bearings, but may have a destabilizing effect under heavily loaded conditions. These findings provide critical insights for optimizing the stability regimes for textured journal bearings in high-speed applications.