COMBINED INFLUENCE OF JOURNAL MISALIGNMENT AND WEAR ON THE PERFORMANCE OF ORIFICE COMPENSATED NON-RECESSED HYBRID JOURNAL BEARING IN TURBULENT REGIME

摘要

Non-recessed hybrid journal bearings are extensively used in machine tools under the condition of heavy loads and higher speeds. The applications of non-recessed bearings are quite wide and varied owing to their superior performance and relative simplicity of manufacture as compared with recessed bearings. Due to unprecedented technological advances during last few decades, the operating condition of machine has become more exact and stringent. This has necessitated that the design of bearing should be based on more accurately and predicted design data. During the last few years many studies related to non-recessed hole-entry bearing have been reported in the literature. Dufrane et al. [1] analyzed a worn bearing in a steam turbine operating at low speeds. They established a geometrical model considering the worn region of a bearing, in order to include it in the calculations. They showed that the wear most often occurs symmetrically on the bottom of bearing. A study by R.K.Awasthi et al. [2] demonstrated that the wear affects the bearing performance quite appreciably and for an accurate generation of bearing characteristics data, the consideration of wear in the analysis is essential. Further, the shaft misalignment in rotating system is one of the most common causes of the wear. Thus, the analyses based on the assumption that the journal and bearing are properly aligned may not be much realistic. Therefore, for a realistic prediction of the journal bearing performance characteristics data, the consideration of journal misalignment in the analysis is quite desirable from the view point of generating realistic bearing characteristic data. Turbulent flow in bearings occurs due to the high speed operations and due to the use of unconventional fluids. Many studies concerning the performance of misaligned journal bearings and these bearings operating in turbulent regime carried out and reported in literature [3, 4, 5, 6].