外文翻译--润滑和摩擦学在海水水力活塞泵中的应用.doc

设计巴巴工作室 附录二 外文翻译 英文文献 lubrication and tribology in seawater hydraulic piston pump Abstract: Water hydraulic systems have provoked major interest because of the human friendly and environmental safety aspects. Piston pump is one of the most frequently used hydraulic units in recent engineering technique.In water hydraulic piston pump,poor lubrication is more likely to happen than in oil hydraulic one because of difference in properties between water and oil.So there are some key problems such as corrosive wear and erosion,which are investigated briefly.Many new materials have been developed,which give longer life expectancies with water without corrosion and erosion.A new type of seawater hydraulic piston pumps with better suction characteristics had been developed at HUST.Much of this research has concentrated on new materials,structureand experiments,which are also specially introduced. Keywords: water hydraulics;pistonpump;lubrication;test;material INTRODUCTION The earliest hydraulic systems used water as the hydraulic fluid.This restricted the working temperature range and caused corrosion as well as lubricating problems.It was not until the late 1920s that mineral hydraulic oils were introduced.Consequently, the oil became the main pressure medium of hydraulic applications.Recently,the demand for usingpure tap water(excluding seawater) as a pressure medium in hydraulic applications has increased due to its availability,easy maintenance,its low cost and high safety levels against pollution and fire hazard.So,water hydraulics can be used in new application areas such as food processing,pulp and paper industry,medicine,glass making,coal mining and nuclear industry. Water is characterized by very low viscosity in comparison with mineral hydraulic oils.For example, the kinematics viscosity of water at 40 is about 0.7 /s and of typical mineral oil is 3 2 /s. Key problems should be considered in water hydraulic system. Firstly,the very low viscosity must increase th