Analysis And Application Of Sealing Performance Of High Temperature And High Pressure Throttle Valve Seals

A seal is the key to design and manufacture a high-temperature and high-pressure throttle valve.In engineering practice,generally,the main factors affecting sealing effectiveness are the type of a seal,the sizes of a seal groove and a seal,and the material used for a seal.The research point of this paper is to apply an existing seal type(spring energized seals)and size to study,test and explore a suitable engineering material,thereby successfully manufacturing the seals.And through conducting experiments to analyze their sealing performance,the final goal is to apply them to field service.The ultimate temperature and pressure conditions studied in this paper are 120? and 105MPa.Due to the high requirements imposed by the high-temperature and high-pressure working conditions on the temperature resistance and strength of seal materials,as well as the demands of the preload sealing stress,friction coefficient and surface hardness,PTFE and 10%and 20%carbon fiber modified PTFE materials were finally selected for research and analysis.Simulation is an important auxiliary development and research approach in this study and the three materials are equipped with an obvious nonlinear characteristic.On the part of the simulation software,constitutive models need to be used to define the material properties.In this paper,the constitutive models of the three materials above at each research temperature(20?,60?,90? and 120?)were determined by uniaxial tensile test data and an Abaqus fitting function.In order to study seals in this paper,the basic requirements of completing sealing were 120? in temperature and 105MPa in pressure.However,before reaching the temperature and pressure conditions,seals will undergo a complicated deformation process where they may be damaged.Therefore,this paper first theoretically analyzed the reasons for the damage of the seals during the sealing process,and then simulated the process.According to the Mises stress and the Pressure concentration and distribution situation of the seals,the parts that were most likely to be damaged in the dynamic and static sealing process were pointed out respectively,and the relationships between the maximum Mises stress and the minimum Pressure with the temperature,pressure,and material at the most vulnerable part were summarized in static sealing process.Additionally,the sealing performance of the seals was studied.The dynamic and static sealing simulations at 120? and 105MPa were performed on the seals,and the differences in the effective contact stress and the effective contact length between dynamic sealing and static sealing of the three materials were compared.Subsequently,based on the above simulation results,it can be concluded that 10%carbon fiber modified PTFE is the most suitable material for the seals compared with the other two materials.Meanwhile,the variation rules of the sealing performance of the developed seals with the change of temperature and pressure were concluded.Finally,the finished seals made of 10%carbon fiber modified PTFE material were tested and passed the quality inspection,thereby being installed in throttle valves for daily production in an operating area.