Structural Optimization Design Of High Temperature And High Pressure Expansion Joint And Thermodynamic Coupling Analysis

Metal bellows expansion joint is widely used in petrochemical,nuclear power,aerospace and other fields,as a pressure vessel with elastic displacement compensation ability,in addition to meet the requirements of strength,the stiffness must be appropriately reduced to meet the requirements of flexibility to better play the displacement compensation ability.The use of stiffening ring can effectively improve the bearing capacity of expansion joint,but at the same time,stiffening ring makes the stiffness of expansion joint increase sharply,which leads to the weakening of displacement compensation capacity of expansion joint.At present,there is no research on assembly gap between strengthening ring and expansion joint at home and abroad,and thermal stress caused by temperature difference is not considered in the calculation of strength and stiffness performance of expansion joint,which is difficult to meet the practical requirements of high strength and low stiffness metal bellows expansion joint under high temperature and high pressure.In order to further improve the strength of the reinforced bellows expansion joint performance,at the same time,as far as possible to reduce reinforcement ring expansion joint stiffness,improve the elastic compensation ability,in this paper,the high temperature and high pressure reinforced multilayer bellows expansion joint in the cases of the principle of the structure to improve the innovation,with a reinforcement ring is a gap of reinforced multilayer u-shaped bellows expansion joint,The beneficial effects of strengthening ring clearance on the strength and stiffness of the expansion joint are analyzed in detail,and the structural parameters are optimized.In this paper,the temperature field and thermal stress of the expansion joint under high temperature and high pressure were obtained based on the finite element method of thermal-mechanical coupling.Then the temperature field was imported into the statics structure analysis module,and the influence law of strengthening ring clearance on the strength and stiffness performance of the expansion joint was studied and calculated.The results show that the Mises stress and axial stiffness of expansion joints vary with the gap value at different temperature fields.According to the variation of the strength and stiffness of the expansion joint with the gap value of the strengthening ring,the structural optimization design of the expansion joint was carried out,and the optimum gap between the strengthening ring and the bellows was selected to effectively improve the strength performance and displacement compensation ability of the expansion joint,and the feasibility of the optimization results was verified by the actual product.The research conclusions and optimization ideas in this paper provide a new theoretical basis for the theoretical research,optimal design and manufacturing of reinforced bellows expansion joint under high temperature and high pressure conditions,and have certain engineering application value.