基于分形理论的机械密封干摩擦时端面接触特性的研究  

Study on Contact Characteristics of End-face in the Mechanical Seals Under Dry Operating Condition Based on Fractal Theory

作　　者：陈志[1] 蔡垚 顾灿鸿 CHEN Zhi;CAI Yao;GU Canhong(School of Chemical Eng.,Sichuan Univ.,Chengdu 610065,China)

机构地区：[1]四川大学化学工程学院,四川成都610065

出　　处：《工程科学与技术》2021年第3期188-196,共9页Advanced Engineering Sciences

摘　　要：针对碳石墨与碳化钨配对机械密封在干摩擦时端面的接触特性进行研究,在考虑动、静环材料属性,端面微凸体之间的相互作用,摩擦运动方向及摩擦热流的基础上,建立了3维粗糙实体与理想光滑刚体的转动摩擦热-力耦合模型,采用ABAQUS有限元分析软件对其瞬时干摩擦过程进行数值模拟。研究结果表明:粗糙端面的真实接触面积随外载荷的增大近似线性增加;随着外载荷与滑动速度的增加,粗糙端面最大接触压力保持在415~432 MPa范围内,表现出"自限性";粗糙端面温度分布不均匀,外载荷与速度增加会导致端面整体温度增加。端面最高温度的位置受到局部接触压力和局部滑动速度及局部热传递的共同影响;API682标准中提出抑制机械密封的介质压力≤0.07 MPa是有必要的,可以防止干摩擦时密封环温升过高。研究可为探索机械密封摩擦端面热损伤、摩擦磨损研究及机械密封设计提供借鉴。The contact characteristics of end-face in the carbon graphite and tungsten carbide matched mechanical seal under dry operating condition were investigated.Taking account of the effects of the material properties of the seal ring and the mating ring,interaction between the end faces of contact asperities,direction of friction motion and frictional heat-flow,a three-dimensional thermo-mechanical coupling model of rotational friction between a rough entity and a smooth rigid entity was established.The instantaneous dry friction processes were numerically simulated by the ABAQUS finite element analysis software.The results showed that the true contact area of the rough face increased approximately linearly with the increase of the external load.Moreover,with the increase of external load and sliding velocity,the maximum contact pressure of the rough face was maintained in the range of 415~432 MPa,which is"self-limiting".The temperature distribution on the sealing end face was uneven,the increase of external load and velocity will lead to the increase of the overall temperature of the end face.The position of the maximum temperature on the rough surface was affected by the local contact pressure,the local sliding velocity and the local heat transfer.It is necessary for the containment seal in API682 that the medium pressure should be less than or equal to 0.07 MPa,which could prevent the temperature rise of the sealing ring from being too high during dry friction.The studies provides a reference for exploring the thermal damage,friction and wear problems of the end faces of a mechanical seal,and may help the design of the mechanical seal under dry operating condition.

关 键 词：机械密封 干摩擦 接触特性 真实接触面积 接触压力 分形 回转模型 

分 类 号：TH117.1[机械工程—机械设计及理论]