The Finite Element Analysis And Experimental Validation Of Metal Bellows Mechanical Seal

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.