Study On The Influence Of Sealing Clearance On Pressure Resistance Under Double Magnetic Source Structure

As a new type of seal,magnetic liquid seal is widely used in chemical industry and military industry because of its advantages of zero leakage,high reliability and long life.However,when the sealing gap is large,the magnetic liquid seal cannot achieve the pressure resistance conditions required for its work.Therefore,in order to improve the pressure resistance of magnetic liquid seals with large gaps,it is necessary to clarify the influence of the seal gap on the performance of magnetic liquid seals,and then to propose corresponding solutions.In this study,we explore the theoretical,simulation,and experimental aspects of the seal gap to find out the law of pressure resistance under different seal gap conditions.The results of this research will not only provide important references when designing sealing structures for magnetic fluids with large gaps or improving the pressure resistance of the original seals,but will also provide some reference when replacing or repairing key seals for magnetic fluids.The following studies were conducted in this thesis.(1)A new type of dual magnetic source seal structure was designed,and the feasibility of the structure was confirmed by simulation and experimental verification,especially under the condition of large gap seal,the pressure resistance of the structure is more outstanding compared with the single magnetic source structure.(2)Maxwell is used to optimize the design of the tooth parameters of the pole shoe,i.e.tooth height,tooth width and tooth slot width.For the deficiencies in the general method such as missing data selection range and not considering the influence between parameters,the orthogonal experimental design method was proposed,and the optimal tooth structure was finally determined to be 0.5 mm in tooth width,0.7 mm in tooth height and 0.8 mm in tooth slot width.(3)The relationship between the seal gap and the pressure resistance value of four different seal structures,namely,uniform symmetric,symmetric non-uniform,uniform non-symmetric and non-uniform symmetric,is analyzed,and it is concluded that the pressure resistance value decreases as the seal gap increases,and the position of the seal tooth shape has less influence on the pressure resistance value,and the magnetic induction intensity curves within the seal gap corresponding to the same tooth shape parameters are the same.(4)The temperature field simulation analysis of the double magnetic source seal structure shows that the temperature rise is only 5℃,so cooling measures are not required.A seal pressure test bench was built and static and dynamic seal experiments of the magnetic liquid seal were conducted to further verify the correctness of the simulation results.The relative error between the theoretical and experimental values increases with the increase of the seal gap.(5)The pressure resistance value obtained by changing the shaft diameter or the inner diameter of the pole shoe varies for the same size seal jacket.Specifically,if the seal gap of the original structure is increased,in order to reduce the loss of the pressure resistance value,the preferred method is to increase the inner diameter of the pole shoe;if the seal gap of the original structure is reduced,in order to obtain a larger pressure resistance value,the preferred method is to increase the shaft diameter.84 figures,20 tables,and 83 references.