Research On Compound Seal Structures Of Spindle Under Different Temperatures By Static And Dynamic Numerical Simulation

Seal structures of the spacecraft are in various forms, and most of themwork in harsh environments for critical parts, its sealing performance has adirect impact on the launch and operation of spacecraft. The two types of rubbercompound seal structures of movement spindles (reciprocating spindle, rotaryspindle) in a particular model spacecraft are studied on numerical simulation inthis subject, in order to investigate its sealing performance when installed, staticunder pressure and dynamic under pressure, at three different temperatures of20℃,-40℃and120℃.Two compound seal structures are all composed by rubberauxiliary seals and filled PTFE main seals. The study by numerical simulation,at different temperatures under various operating conditions, can have acomprehensive understanding of the sealing performance of the two structuresto predict the weakness, improve sealing reliability.The fluid static and dynamic sealing principles are analyzed firstly, and theperformance characteristics of PTFE and rubber materials are introduced here.Due to the particularity of the rubber material, its mechanical properties cannot be simply characterized by elastic modulus and Poisson ratio, so theconstitutive model and its establishment method by experiments are discussed,and the constitutive equations at different temperatures are established by fittingmaterial stress-strain data using MARC obtained by mechanical experimentsunder their respective temperatures.The nonlinear FE model of compound seal structures of the reciprocatingspindle and rotating spindle are established respectively, its static and dynamicsealing performance are simulated and studied respectively under differenttemperatures to obtain their respective displacement, deformation and stressfield distribution, based on this, fully analyzing the influence and its law whichtemperature variation and spindle movement have on static and dynamicperformance of the two composite seal structures, finding the weaknessmeanwhile.The key factors determining the dynamic sealing performance of two kindsspindles are explored separately; for sealing structure of the reciprocating shaft, through the inverse solution of Reynolds equation, the oil film thickness on thekey points are calculated and obtained theoretically, which determine theamount of leakage.Finally, the external operating conditions (such as the working mediumpressure P and the pre-compression rate W) and their own structural parametersare analyzed by numerical simulation, to find the influence they have on theirown sealing performance, and analyze what major impact P and W, lip thickness,fillet radius of the L-shaped ring and overall width, intermediate width of thesquare ring have on their static and dynamic sealing performance respectivelyand the influence law. Based on this, recommended reference values of thestructural parameters are given to make them have better comprehensive sealingperformance under given conditions in this paper, providing reference to designsuch or similar kinds of composite sealing structures.