【作者】 吴卫杰；

【导师】 刘录； 郑学鹏；

【作者基本信息】 北京石油化工学院 ， 机械工程（专业学位）， 2015， 硕士

【摘要】 金属波纹管机械密封是高温工况下应用极其广泛的一种动密封结构,随着使用工况的不断变化,金属波纹管机械密封因其轴或轴套不受磨损、浮动性好、不易堆积杂物等诸多优点被大量应用。本文通过运用ANSYS12.0有限元商业分析软件,根据金属波纹管机械密封的使用工况、使用压力、使用轴径对模型进行模拟分析,最终得到在一定条件下,波纹管直径变化对机械密封端面受力、变形和波纹管应力的影响。通过ANSYS模拟计算得到了:(1)金属波纹管机械密封的波纹管直径改变(其他尺寸不变)对波纹管的受力影响不明显,最大误差小于10%。挤压成型金属波纹管在压缩和受压时,最大应力出现在波峰和波谷处。非对称金属波纹管的应用可以改善波谷和波峰的受力情况。(2)金属波纹管机械密封随着直径的增加,密封端面变形变大,接触间隙变宽,接触面减小,接触应力的最大值增大。(3)在过盈装配过程中,不对称的配合会产生转矩,使端面产生变形,机械密封直径越大,变形越大,在装配过程中增大配合面的比例,减小非配合部位的结构尺寸将会大大改善密封环端面的变形情况。(4)本文通过端面比压、载荷系数、反压系数、介质压力的关系绘制了介质压力、波纹管压缩量和端面比压的关系图,方便波纹管压缩量的选取和判定端面比压的大小。通过实验验证了:(1)在金属波纹管机械密封压缩和受外压的情况下,端面变形是真实存在的,且和有限元分析结果接近;这种变形使得密封端面外径接触,内径不接触,出现了接触间隙,在受外压的情况下(和试验中一样),高转速会引起大的动压效应。(2)机械密封通过跑和可以减轻端面变形造成的影响,减小端面动压效应,使机械密封运行趋于平稳。通过本文的有限元模拟和实验验证,得出金属波纹管机械密封直径变化对端面变形影响的规律,对工程实践有一定的指导意义。更多还原

【Abstract】 Metal bellows mechanical seal is an extremely widely used dynamic seal structure under the high temperature condition. With the unceasing change of working condition, metal bellows mechanical seal is widely applied because of no wear of the shaft or shaft sleeve, good floatability, no easy to pile up sundry, and many other advantages. In this paper, by using commercial finite element analysis software ANSYS12.0, we can simulate and analyze metal bellows mechanical seal under different working conditions, different pressure and different diameters of axle. Finally, we obtain the effect of the metal bellows’ diameter on deformation and stress of seal face and bellows under the given condition.Some conclusions are obtained by simulation calculation:(1) Diameter changing(other size unchanged) of metal bellows mechanical seal has no obvious effect on the stress of the bellows, and the maximum stress appears at the peaks and troughs of the bellows. The application of asymmetric metal bellows can decrease the stress of the troughs and crests.(2) With the increase of diameter, deformation of sealing end face increases, contact gap grows wider, the contact area is reduced and the maximum contact stress increases.(3) In the process of interference assembly, the asymmetric cooperation will produce torque. It leads to the deformation of seal face, the greater the diameter, the greater the deformation. If we increase the ratio of the assembly area, reduce the structure size of the no-matching parts, the deformation of seal face will be greatly decreased.(4) In this paper, through the relationship between the end face specific pressure, the load coefficient, the opposite pressure coefficient and the medium pressure, I mapped the diagrams of the medium pressure, the bellows compression and end face specific pressure. It is convenient to select the amount of bellows compression and judge the level of the end face specific pressure.Some conclusions are verified by experiments:(1) When mechanical seal of metal bellows is under the condition of compression or external pressure, end face deformation is real, and it is close to the result of finite element analysis calculation. This deformation makes end face contact at outer diameter, causes contact gap at inner diameter. When mechanical seal is under external pressure such as in this experiment, it will lead to great dynamic pressure effect on the condition of high rotate speed.(2) Through the running-in, Mechanical seal can decrease the effect of end face deformation, reduce the end face dynamic pressure effect and make mechanical seal run steady.Through the finite element simulation and experimental validation, We get the face deformation regularity with metal bellows mechanical seal diameter changing, and this has certain guiding significance in engineering practice.更多还原