LNG High Pressure Axial Flow Check Valve Sealing Structure Research On Multi-objective Optimization

LNG ultra-low temperature and high pressure axial flow check valve is an important part of LNG storage and transportation system,its safe and reliable operation is the key factor to ensure the normal operation of the system.And good sealing performance is an important index to evaluate the safety and reliability of check valve.During the actual research and design process,there are many problems in the design of check valve seal structure.In view of these problems,this paper takes a certain LNG of ultra-low temperature and high pressure axial flow check valve as the carrier,using finite element analysis method and multi-objective optimization theory to carry out a series of research on its seal structure,the specific research contents are as follows:(1)Based on the theory of solid mechanics and temperature field,the LNG ultra-low temperature axial-flow check valve is analyzed by thermo-solid coupling finite element method and checked by stress assessment to ensure that valve can meet the basic requirement of structural strength.Based on the fluid mechanics theory,UDF dynamic grid technique is used to analyze and calculate the dynamic characteristics of the check valve during the closing process,and the movement parameters of the valve core during the closing process are obtained,at the same time,the boundary conditions are provided for the optimization calculation and analysis in the following chapters.(2)Based on the elastic contact theory and transient dynamics theory,the nonlinear finite element simulation of the collision pro cess between the valve core and the valve seat when the check valve is closed was conducted by using ABAQUS software,and the rpy file of the finite element calculation process was obtained,which provided necessary documents for the optimization calculati on in the following chapters.The force of the valve core and the valve seat and the sealing condition of the sealing structure during the check valve closing process are obtained.The results show that the force of the valve core and the valve seat and th e sealing condition of the sealing structure can meet the basic requirements of operation.However,there is still a lot of room for optimization.On the one hand,it provides the necessity for subsequent optimization design,and on the other hand,it prov ides a reference object for the optimized calculation results.(3)Based on the multi-objective genetic optimization algorithm,determine the objective function,use Isight integration software,edit Python language,and call ABAQUS software to automatically and optimally design the size of the check valve seal structure to improve the reliability of the sealing under the impact of the check valve.A finite element analysis is performed on the optimized results.Comparing the models before optimization,it can be seen that the reliability of the seal is significantly improved after optimization.Through the above research,the stress and sealing conditions of the LNG ultra-low temperature axial flow check valve under shock load during the closing process were revealed,which has provided new design ideas and research methods for the optimization design of the check valve spool and valve seat sealing structure.