Study On End Face Structure And Sealing Characteristics Of Mechanical Seal With Double-tip Groove

In order to improve the sealing performance of dry gas seal and enhance its service life,this paper takes the dry gas seal end face as the research object and proposes a new double-tip groove seal end face.Established its geometric model and mathematical model.The finite difference method is used to solve and analyze.The MATLAB calculation program is written to solve the pressure distribution of the end face film and the relevant sealing performance parameters.Comparing the sealing performance of the new double-cushion groove and the common spiral groove with two sets of variables of film thickness and rotation speed,The influence of the structural parameters of the end face of the sealing ring on the opening force,leakage,stiffness and rigid leakage ratio of the double-cushion groove is studied,and the relevant variation law is obtained.Through research,the working mechanism of double-tip dry gas seal is obtained,The sealing performance of the double-cushion dry gas seal is improved,which provides a theoretical basis for the structure and practical application of the dry gas seal end face,including:(1)Compared with the ordinary spiral groove,when the film thickness value is greater than 3,the optimization effect of the double-tip groove on the sealing performance is weak;When the film thickness value is less than 3,the opening force and rigidity of the double-cushion dry gas seal are obviously improved,the leakage amount is slightly increased,but they are kept within a reasonable range,and the double-cushion groove has a strong effect on the optimization of sealing performance.(2)As the circumferential ratio of the tank increases,the opening force,stiffness,and just leak ratio tend to increase first,then gradually decrease.The amount of leakage first grows and then gradually stabilizes.When the circumferential ratio of the tank is in the range of 2 to 3,while ensuring that the leakage amount meets the requirements,The parameters such as opening force and film stiffness have large values,and the optimum ratio of the circumferential ratio of the groove is 2.5.(3)As the radial ratio of the dam increases,the opening force,stiffness,and just leak ratio tend to increase first,and then gradually decrease.The amount of leakage first increased and then stabilized.When the radial length ratio of the dam is 0.75~0.9,While ensuring that the leakage amount meets the requirements,the parameters such as opening force and film stiffness are relatively large.The sealing radial ratio is optimally 0.85.(4)When the depth of the two spiral grooves is constant,as the groove depth of the circular groove increases,the performance parameters such as opening force and stiffness generally decrease.When the depth of the arc groove is 3~5,the opening force and the stiffness are both large when the leakage amount is required to be required,and the opening force and the stiffness are maximized when the arc groove depth is 3.(5)As the groove depth of the spiral groove 1 increases,the opening force,the leakage amount,and the stiffness first increase,and then gradually decrease.When the value range is 8~16,the parameters such as opening force and film stiffness are larger when the leakage amount is guaranteed.As the groove depth of the spiral groove 2 increases,the opening force,the stiffness and the leakage amount first increase and then gradually decrease,and the just leak ratio gradually decreases and then increases.When the value range is 5~10,the parameters such as opening force and film stiffness are larger when the leakage amount is guaranteed.The preferred groove depth of the spiral groove 1 is 12,and the preferred groove depth of the spiral groove 2 is 8.