Optimization of structural parameters of spiral groove pump-out dynamic pressure seals face based on fluid-solid-thermal coupling analysis

LI Shuang-xi, LIAO Hao-ran, LI Shi-cong, LIU Xing-hua
(School of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029,China)

Abstract: Aiming at the problem that the improper selection of the parameter structure of the sealing end face causes the dynamic and static ring to burn down during highspeed rotation of the seal, the end face parameters of the spiral groove pumpout dynamic pressure seal were optimized. Based on the governing equations of gasphase fluids, the fluidsolidthermal coupled finite element analysis method was used. Considering the effects of dynamic and static ring deformations and thermal deformations on fluids, the effects of end face parameters such as helix angle, number of grooves, ratio of grooves to weir, ratio of grooves to dam, and depth of grooves on sealing performance such as opening force, leakage, friction power consumption, and gas film stiffness were studied. An optimization scheme for the design of spiral groove pumpout dynamic pressure seal was proposed. The experimental research method was used to verify the accuracy of the calculation model. Comparing the microscopic morphology of the sealing end face before and after operation, it was found that the test sealing end face had almost no friction and wear, which verified the sealing feasibility. The results indicate that the opening force and the rigidity are large, the leakage rate and friction power consumption are small by comparison, and the comprehensive performance of the seal is the best when the helix angle is 15°~20°, the number of grooves is 12~16, the ratio of groove to weir is 0.5 to 0.6, the ratio of groove to dam is 0.65~0.75, and the depth of the groove is 7 μm~10 μm.
Key words: pump-out; spiral groove; structural parameter; sealing performance; fluid-solid-thermal coupling