| LNG(Liquefied Natural Gas)pipeline are installed at the normal temperature,and used in the condition of low temperature and pressure,effected by low temperature and pressure,so the pipeline face with complicated working conditions.For LNG is flammable,explosive,and easy to spread,it is necessary to analysis the structural integrity and reliability of LNG pipeline to prevent leakage and fire and to ensure the safe and efficient operation of LNG filling station.Aiming at this issue,this paper do the following research:1.In order to study the temperature variation of LNG pipeline,the temperature measurement experiment of LNG pipeline is carried out.According to the layout of the LNG pipeline and the requirement of temperature measurement,a set of temperature measurement scheme is formulated.The temperature measurement system and device are tested to ensure the feasibility of the measurement system.Complete temperature measurement results and analysis the measurement data to summarize the temperature change law of LNG pipeline.2.Based on the thermal stress theory and finite element method,a thermal-structure coupled finite element simulation of a system including piping,flanges,gaskets and bolts was carried out,considering bolt preload,pressure,temperature,pipe structure and mechanical properties of materials at low temperatures.Summarize the calculation method of bolt pre-tightening force of the flange connection.According to results of the finite element analysis,the contact stress distribution rule of gaskets of flange in LNG pipeline is studied,and the structure strength of LNG pipeline and the sealing performance of the flange are evaluated.3.The influence of design parameters,assembly parameters and material properties of flange to the sealing performance of flange in LNG pipeline is studied.According to the results,the design parameters and assembly parameters of the flange are optimized to improve the strength and sealing performance of the bolted flange connection in LNG pipeline. |
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