Thermal-Structural Coupling Analysis Of LNG Pipeline With Bolted Flange Joints

LNG(Liquefied Natural Gas)pipeline is important medium between the processes of storing,transporting and using of LNG.It works in the severe environment of low temperature and pressure for a long time.Since LNG has the character of flammability,explosion and low temperature,the leakage of LNG would result in series of serious hazard.Hence,the safely running of LNG pipeline is the important assurances of LNG efficient usage.This thesis set the pipeline of LNG fueling station as the research target,and focused on the structural integrity and tightness of the pipeline spread following research: Firstly,the thesis briefly introduced the LNG fueling station and its primary technology processes,subsequently summarized the current research situation of LNG devices and the gasketed bolted flange connection in domestic and abroad.Secondly,figured out the actual working condition of pipeline with temperature measurement of pipe wall,studied the material properties of pipe and gasket with experiment results and reported data.Then,based on the basic theory of the thermal conduction,the thermal-structure coupled finite element model that considering the nonlinear characteristics of gasket was carried out,simultaneously the evaluation criterion of pipeline strength and sealing performance was proposed.According to FEA results of pipeline,the distribution of gasket contact stress in LNG pipeline was discussed,the structure strength and the sealing performance of LNG pipeline were evaluated.At last,the influence factor of pipeline sealing performance was studied,the design parameters of pipeline were optimized with the strength and tightness as index,the range of pipeline assembly parameter was determined lately.The above research provides references on design and assembles of LNG pipeline,and it has theoretical value and engineering significance.