非接触式机械密封中的磁流体热动力效应研究

项目名称： 非接触式机械密封中的磁流体热动力效应研究

项目编号： No.51205184

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 机械工程学科

项目作者： 周剑锋

作者单位： 南京工业大学

项目金额： 25万元

中文摘要： 非接触式机械密封是旋转设备防止泄漏的重要部件，其在定转速时密封压力恒定，不能适应压力波动工况。本项目提出采用磁流体作为非接触式机械密封端面润滑介质的新思想，利用磁流体粘度受磁场控制的特性产生可控的流体动压效应，实现密封压力和摩擦功耗的在线控制。研究温度和磁场强度对磁流体粘度和导热系数的影响规律，建立动环和静环端面间磁流体膜边界速度滑移和温度阶跃的表征方法；根据磁流体膜的摩擦热流密度、粘度和温度的协调关系，研究物性、几何和操作参数对磁流体膜剪切热效应的影响规律；研究磁场、静环、磁流体膜与动环的热力耦合作用特性，建立磁-热-流-固多场耦合的解析和数值分析方法；研究外磁场作用下非接触式机械密封端面间磁流体膜的热动力效应，获得磁流体膜温度、压力分布及泄漏率等密封特性参数，揭示磁流体热动力效应的形成机理并进行试验研究。研究结果可为具有变工况自适应能力的新型非接触式机械密封的研发提供理论依据。

中文关键词： 磁流体；纳米磁颗粒；动压润滑；机械密封；自适应控制

英文摘要： The non-contact mechanical seal is an important shaft sealing unit installed in rotating equipment. Its sealing pressure always remains constant at invariant rotational speed and for this reason, it can not seal the medium with surge pressure as well as that with constant pressure. The idea for lubricating the end faces of non-contact mechanical seal by using the magnetofluid is proposed in this project. The alterable viscosity of magnetofluid can be utilized to generate controllable thermohydrodynamic effect of lubricant film between the end faces of mechanical seal, and accordingly the online control of sealing pressure and friction power consumption of mechanical seal can be realized by controlling the intensity of magnetic field which exerts on magnetofluid film. Based on the investigation into the influences of temperature and magnetic intensity on the viscosity and coefficient of heat conductivity of magnetofluid, the characterization method for velocity slip and temperature jump on the boundaries of magnetofluid film which is between the two end faces of sealing rings can be established. The influences of physical, geometrical and operating parameters on the thermal results of frictional heat effect of magnetofluid film will be investigated. In consideration of the coupling effect among the magnetofluid

英文关键词： magnetic fluid；nano magnetic particle；hydrodynamic lubrication；mechanical seal；adaptive control