【作者】 李宁；

【导师】 穆塔里夫·阿赫迈德；

【作者基本信息】 新疆大学 ， 机械工程， 2016， 硕士

【摘要】 螺旋槽机械密封依靠密封端面上的螺旋槽产生的楔压力将润滑液体挤入端面之间,建立一层端面流体膜,从而形成动环-液膜-静环摩擦副的润滑系统,使得动静环之间只有流体的内摩擦而避免了直接刚性接触;螺旋槽机械密封的这种工作方式使得密封件具有介质泄漏量少、动静环磨损小、密封装置寿命长、经济性突出等优点。但是随着机械密封工作参数的不断提高,摩擦副界面很容易发生热流固耦合的效应,造成密封运行的不平稳、密封环磨损严重,使得密封失效,因此需要用多场耦合的理论去探究摩擦副的密封性能。同时螺旋槽机械密封系统摩擦副尺寸小、槽型复杂,用试验探究其全部密封性能有一定难度且不经济,需要借助数值计算的方法来进行一定的分析研究。本文首先分别建立了有螺旋槽和无螺旋槽的流体膜的三维模型,数值计算了密封间隙流场的动力特性,获得流场压力的分布结果,发现带有槽的流场压力明显要高于无槽的,表明螺旋槽密封确实产生了动压作用;同时对比分析了密封环转速与介质压力对两种密封形式的密封性能(泄露量、承载力)的影响规律,为机械密封的工况环境选择提供了依据;其次,依据热流固单向耦合分析理论,建立了螺旋槽机械密封摩擦副模型,对完整液膜进行了压力场和温度场的分析,得到了液膜的压力和温度分布规律,然后分别压力和温度作为边界条件载入到密封环静力学分析中进行耦合变形分析,获得了动静环的受力和变形规律,并进一步探究了密封的转速、介质压力对动静环变形的影响情况;研究结果为螺旋槽机械密封的失效机理研究以及密封性能的优化提供科学指导。更多还原

【Abstract】 The spiral groove mechanical seal is a hydrodynamic seal, which is realized by based on the spiral groove on the sealing surface. The wedge pressure that the seal generated took the medium into the seal clearance to form fluid-film, thus a lubrication system of dynamic ring- film- static ring was formed. As a result, the sealing face only has the internal friction between the fluids and avoids the direct contact between the dynamic and static ring. So it is small leakage, the little wear, the long service life and the prominent economy. However, with the growth of the parameters of the seal medium, the sealing performance deteriorates rapidly, which will cause sealing ring uneven stress, leading to the sealing ring friction, wear and heat crack. So the fluid- film and the sealing ring is a coupling relationship, and it is more close to the actual to use coupling theory to study them.Firstly, three-dimensional finite element models were established for spiral groove and non-groove face, then the dynamic characteristics of the fluid-films are simulated to get their pressure field, which verify that the sealing face with spiral groove has obvious hydrodynamic effects. At the same time, a comparative analysis is done to study the effect of the rotation speed and the different pressure of medium on the sealing performances; Secondly, based on one-way coupling analysis theory, the friction model is build, and then the completed fields are analyzed to the fluid- field, the distribution laws are obtained. After that, the results of pressure and temperature are loaded separately into the static analysis of sealing ring as the boundary conditions for coupling analysis to get the maximum stress and strain of sealing sing respectively. Also, the influences of the rotation speed, the different pressure and the viscosity of medium on the deformation of sealing ring are explored.更多还原