Plain Circular Bearing Research Articles

Stability Analysis of a Flexible Rotor Supported by Plain Circular Bearings with Micropolar Fluid

This paper describes the stability analysis of a flexible rotor supported by two horizontal identical plain circular bearings lubricated with Non-Newtonian fluid as micropolar fluid. The basic principles of hydrodynamic lubrication are also discussed here to study the dynamics of rotor bearing system. The mechanisms of hydrodynamic film generation and the effects of operating variables such as velocity, load, design parameters etc., on the performance of such films are outlined. The effects in hydrodynamic lubrication of rotor system using Non-Newtonian lubricant found some undesirable vibrations, undergoes periodic and quasi-periodic motion is described and their influence on bearing performance assessed. The numerical solution of modified Reynolds equation under micropolar lubrication with the usual lubrication assumptions is considered which yield the pressure distribution to find the couple of resulting forces in radial as well as in tangential direction.

Effects of bearing orientation on the static performance of micropolar lubricated lobe bearings

In contrast to plain circular bearings, orientation of the lobe bearings with respect to a fixed load direction can influence the bearing performance characteristics. Expressing the lobe bearing orientation in terms of an angle, which in this study is referred to as bearing orientation angle, its effect on static performance characteristics of three types of micropolar lubricated lobe bearings is investigated. For this purpose, finite element method is adopted for numerical solution of the modified Reynolds equation. It is found that against the most common mode of the lobe bearing orientation, which is with the bearing orientation angle zero, performance of the lobe bearings can be improved by suitable selection of the bearing orientation angle. Also, lobe bearings with comparatively lesser number of lobes are more affected by the orientation angle.

Wave Journal Bearing with Compressible Lubricant—Part I: The Wave Bearing Concept and a Comparison to the Plain Circular Bearing

To improve hydrodynamic journal bearing steady-state and dynamic performance, a new bearing concept, the wave journal bearing, was developed at the author's lab. This concept features a waved inner bearing diameter. Compared to other alternative bearing geometries used to improve bearing performance such as spiral or herring-bone grooves, steps, etc., the wave bearing's design is relatively simple and allows the shaft to rotate in either direction. A three-wave bearing operating with a compressible lubricant, i.e., gas is analyzed using a numerical code. Its performance is compared to a plain (truly) circular bearing over a broad range of bearing working parameters, e.g., bearing numbers from 0.01 to 100.

Hydrodynamic instability of self-acting journalbearings of infinite length in the turbulent regime

An analysis for the determination of the conditions of dynamic stability of hydrodynamically lubricated plain circular bearings of finite length with turbulent flow is presented. The conditions for both static and dynamic stability were calculated from the response to a small random disturbance. The study of static stability was necessary as a first step. The dynamic stability was investigated with the Routh-Hurwitz criterion by using the perturbation (or linearization) technique. The results are fully analytical and are in the closed form. This allows the computation of data and the construction of stability charts for a wide range of parameters involved for the determination of the stability threshold.

Analysis of Plain Cylindrical Journal Bearings in Turbulent Regime

This paper presents a simplified steady-state analysis of turbulent lubrication. Load-carrying capacity, attitude angle, and fluid film stiffness for plain cylindrical journal bearings operating in the turbulent regime are presented. Simple, easy to use relations for the calculation of load-carrying capacity were generated. Fluid film stiffnesses are included so that they can be used to calculate system critical speeds. In the analysis presented here, side leakage is neglected; however, existing published data on a 360 deg plain circular bearing were used to establish a correlation factor between laminar and turbulent leakage factors.