低速船用柴油机主轴承弹流润滑性能分析

以某低速二冲程船用柴油机为研究对象,结合弹性流体动力学、多体动力学以及有限元方法,建立了包含机架-机座-主轴承盖-曲轴的整机动力学润滑耦合分析模型,对低速船舶柴油机主轴承的润滑性能进行研究。研究结果表明:第7主轴承(靠近飞轮端)润滑性能最为恶劣,总压峰值达到87.95 MPa,高出其他主轴承19.7%至413.7%不等;在整个推进工况主轴承油膜厚度均满足最小膜厚要求;不同工况轴承液动润滑和混合润滑的时间占比也不尽相同,液动润滑占比从100%负荷的20.7%提高到25%负荷的99.3%;轴承结构对主轴承的润滑磨损性能有较大影响,径向间隙的设计须综合考虑油膜承载与摩擦功耗。

Elasto-hydrodynamic Lubrication Analysis of Main Bearings for aLow Speed Marine Diesel Engine

The elasto-hydrodynamic theory (EHD) coupling with multi-body dynamic theory (MBD) and finite element method (FEM) were applied to establish the whole engine model of dynamic lubricating, including engine frame, engine base, main bearing cover and crankshaft, to study the lubricating performance of main bearings of low speed marine diesel engines. The results showed that the 7th main bearing,which was near the flywheel end was in the worst condition where peak total pressure had reached 87.95 MPa, higher than other bearings by 19.7%~413.7%. The lubrication of all bearings met the minimum oil film demand under all propulsion load, while time ratio of hydraulic and mix lubrication varied along with the change of working conditions.The time ratio of the hydraulic lubrication changes from 20.7% to 99.3% when the load dropped from 100% to 25%.The design of radial clea-rance needs to take lubrication performance and energy loss into account comprehensively as bearing structures are of much importance to its lubricating and wear performance.