基于润滑油颗粒效应的柴油机轴系扭振特性研究

以船用中速机顶环为研究对象,基于混合润滑模型、微凸体接触模型和颗粒承载模型,引入颗粒的粒径和质量浓度,提出了一种活塞环-缸套液固两相润滑模型,分析了颗粒的承载能力、摩擦力、摩擦功耗,探究了固体颗粒对中速机润滑性能的影响。在此基础上,以往复摩擦机为研究对象建立了考虑摩擦力矩的轴系扭振计算模型,以此分析含颗粒润滑状态对扭振的影响并进行了试验验证。研究表明:固体颗粒使活塞环-缸套间的最小油膜厚度和摩擦力增大;柴油机轴系的扭振增大,其中2、4谐次对应扭角增大的比例最大。

Investigation of Torsional Vibration Characteristics of Diesel EngineShafting Based on Lubricant Particle Effect

The piston top ring of medium-speed marine engine was taken as the research object. Based on the hybrid lubrication model, micro-convex contact model and particle bearing model, and by referring to the size and mass concentration of particles, a liquid-solid two-phase lubrication model for piston ring-cylinder liner was proposed. The bearing capacity, friction force and friction power consumption of the particles were analyzed, and the influence of solid particles on lubrication performance of medium speed engine was explored. Furthermore, by taking the reciprocating friction machine as the research object, a calculation model of the shaft torsional vibration which considered the friction torque was established. The influence of particle lubrication state on torsional vibration was also investigated and verified by experiments. The results show that when the lubricating oil contains solid particles, the minimum oil film thickness and friction between piston ring-cylinder liner increases; the torsional vibration response of diesel engine shafting accordingly increases; and the ratio of the torsion angle increases to the maximum in the 2,4 harmonics.