水气共生态下高速动载水膜行为的滑移沟槽机理研究

With the application of sleeve bearing in high speed and super-high speed conditions, the lubrication film is easy to crack and becomes cavitation, wall slip can occur when shear stress exceeds the critical shear stress at the solid-liquid interface. Cavitation accelerates the shedding, wear and noise in the bearing surface, and it is easy to cause the lubricating film oscillation and catastrophic accidents, especially in the external disturbance conditions of the dynamic load and high-frequency vibration of machine tool. Wall slip leads to the lubrication failure and has a great effect on the lubrication characteristics of sleeve bearing. In the present study of sleeve bearing, it is few that the wall slip and cavitation effect are studied simultaneously, and the application of the wall slip in the complex structure bearing is not mentioned. The cavitaiton and wall slip of water film are studied for high speed dynamic spiral oil wedge journal bearing in the dynamic load condition,the main research contents include: The multiple factor coupling lubrication model is established, and the conditions of water supply, the distribution of lubricant medium, dynamic load, cavitation effect and wall slip are considered. The application of wall slip is studied in the performance improvement of sleeve bearing and the influence of the control parameters is analyzed. The performance of combined surface sleeve bearing in the parallel sliding gap and different combined surface shapes are studied. The studies provide a theoretical reference for the design of low viscosity high speed sleeve bearing, the development of various environment-friendly machines and the application of wall slip in engineering.

高速、超高速条件下，滑动轴承润滑薄膜极易产生破裂形成空穴，固液界面上的剪应力会超过极限剪应力在固体表面发生滑移。空穴导致的空蚀现象加速了轴承表面脱落、磨损和噪声，尤其在动载和机床高频振动等外来扰动工况下，容易引起润滑膜振荡和灾变性事故；而界面滑移现象导致的润滑失效对轴承性能的影响也至关重要。目前轴承性能研究中同时考虑界面滑移和空穴效应的极少，而且界面滑移现象在复杂结构轴承中的应用也未提及。本项目研究高速动载螺旋槽滑动轴承的水膜空穴行为和界面滑移现象，主要研究内容包括：建立同时考虑供水条件、润滑剂介质分布、动载工况、空穴效应和界面滑移的多因素耦合润滑模型；研究界面滑移现象在滑动轴承性能改善中的应用以及控制参数影响；研究平行间隙时和不同组合表面形状的组合滑移表面轴承的性能；本项目的完成将为低粘度高速动静压滑动轴承设计技术、各种环境友好型机械的开发及其界面滑移现象在工程中的应用提供理论参考。

高速、超高速切削逐渐成为切削技术和机床的发展主流，轴承作为重要的支撑方式成为影响机床速度和稳定性的重要因素。本项目提出了采用水润滑介质，研究高速动载工况下螺旋槽滑动轴承的水膜空穴行为和界面滑移现象，并且在界面滑移研究的基础上对其进行控制与利用。建立了同时考虑供水条件、润滑剂介质分布、动载工况、两相流和界面滑移现象的数学模型，并进行了数值计算，研究了高速滑动轴承动载工况下的空穴迁移图形、压力分布、油膜承载力和摩擦阻力等，开展了动载工况、界面滑移、空穴行为和转速等对轴承性能的影响，研究了组合滑移表面螺旋槽轴承的性能，探究了温度场对轴承油膜特性的影响规律，完成了动载工况下空穴特性和界面滑移的实验研究。研究结果表明：随着时间的推移，空穴位置的变化是周期性的，油膜空穴沿着轴的转动方向发生迁移，几乎油腔的每一个位置都可能发生空穴，空穴大小呈现逐渐变小再逐渐变大的规律，考虑界面滑移时空穴区域面积稍微有些增大和压力峰值明显降低。随着时间的推移，轴瓦表面和轴表面滑移发生的位置也随着轴的转动方向总体迁移。组合滑移表面螺旋槽轴承相比螺旋槽滑动轴承提高了油膜压力和承载力，降低了摩擦阻力。润滑剂进油温度的提高和进油压力的减小提高了润滑膜的最高温度。空穴和滑移现象的深入研究为轴承更好的应用于高速机床中和界面滑移现象更好的应用于高速动静压滑动轴承设计技术中提供了理论依据。