【作者】 刘伟；

【导师】 刘焜；

【作者基本信息】 合肥工业大学 ， 机械设计及理论， 2008， 博士

【摘要】 在实际的润滑状况下,由于摩擦副自身磨损和外部环境的影响,润滑油内部不可避免的会有固体颗粒进入,形成所谓的液-固二相流体润滑。固体颗粒与润滑油的作用、固体颗粒与摩擦副表面的作用等问题对润滑性能将产生重要的影响,因此,展开液-固二相润滑的研究具有十分重要的理论和实际意义。本文从理论利试验两方面对液-固二相流体润滑进行了研究。结合了考虑流变特性的雷诺方程、液-固二相流体的粘度、密度及油膜极限剪应力等流变参数的变化方程,同时引入颗粒承载和微凸体承载并考虑表面粗糙度的影响,建立了相应的分析模型平和方法。通过研究表明:考虑表面粗糙度的液-固二相流体润滑的研究更加符合实际,微凸体的颗粒以及流体的承载与平均油膜厚度、颗粒浓度、颗粒直径、颗粒屈服应力利表面弹性模草等有很大的关系。深入剑润滑微观尺度,针对多颗粒存在情况下的液-固二相流体润滑问题,引入颗粒的何置、大小、颗粒间拦巨离等参数,建立了润滑模型,并且运用有限元法进行求解,研究了颗粒分布对润滑油膜压力利承载的影响,研究发现颗粒的进入使得颗粒处的油膜压力有了明显的增加,颗粒分布对润滑油膜压力分布和油膜承载有明显的影响。基于欧拉-拉格朗日模型,针对颗粒的动态行为及其对液-固二相流体润滑的影响问题进行了深入的分析,研究发现:颗粒在润滑区域存在三种运动形态,即从润滑区域山口处逃逸、住润滑区域入口处回旋、从润滑区域入口处逃离润滑区域,颗粒的初始位置对颗粒的运动状态有很大的影响,摩擦副的速度利流体的粘度对颗粒在润滑区域的运动也有一定影响。在自行研制的端面摩擦磨损试验机上设计了相应的试验进行了试验研究。通过在润滑油中添加不同种类、大小利含量的颗粒分别进行试验,在线测量了润滑过程中摩擦系数和温度的变化情况。综上,论文分别从颗粒的静态行为和动态行为对液-固二相流体润滑进行了理论分析,并设计相应的试验进行探讨,研究了颗粒行为对液-固二相流体润滑的影响,对促进液-固二相流体润滑理论的发展和完善将起到重要作用。更多还原

【Abstract】 It has been known for many years that various types of particles that come from wear and environment dispersed in oil during the operation of hydrodynamic tribological pairs and formed so called liquid-solid lubrication. Interactions between particles and oil, particles and bounding surfaces of tribological pairs will greatly affect the performance of tribological pairs. Therefore research on liquid-solid lubrication is significant both in theory and practice. This dissertation researches the liquid-solid lubrication both theoretically and experimentally.A mixed liquid-solid lubrication model is studied which considering rheological Reynolds equation, viscosity of liquid-solid lubricant equation, density of liquid-solid lubricant equation. The load carrying of spherical particle and the contacting equation of asperities of surface are also introduced in the model. The results show that it is closer to the reality to do research on liquid-solid lubrication considering surface roughness , the load carrying capacity of particles, asperities and oil has a great relation to average oil film thickness, particle concentration, particle diameter, particle yield stress, surface modulus of elasticity and so on.The effect of solid particles distribution on the liquid-solid lubrication is discussed. The governing lubrication equation for the liquid-solid lubrication is established with the consideration of particles location, diameter and the distance of particles. Based on finite element method, the modelling equation is solved numerically. It shows that a noticeable pressure build-up occurs near the particles, particles distribution have a big effect on pressure distribution and oil load capacity.Based on Eular-Lagrange model, liquid-solid lubrication considering moving particle behaviors is deeply studied. It is shown that: there are three kinds of particles movement forms in lubrication system, which are escaping form inlet, escaping from outlet and encircling near the inlet of lubrication area. The initial location of the particle has a big influence on particle movement, and the velocity of tribological pairs and the viscous of oil also have some influence on it.Using end-face friction and wear tester made by our institute, an experiment of liquid-solid lubrication is designed, the effects of particle properties, sizes and concentration on liquid-solid lubrication are studied by online measurement of the friction pair’s temperature and friction coefficient. In summary, both static behaviors and dynamic behaviors of particles on liquid-solid lubrication are studied in this dissertation, a proper experiment designed and carried out. The research results will play an important role on promoting the development of liquid-solid lubrication theory.更多还原