Stress and Deformation Simulation of LNG Pipeline during Non-full Liquid Pre-cooling Process
In order to investigate the influence of liquid level relative heights on the stress and deform-ation of LNG pipeline,a coupled numerical calculation model of temperature field and structural field was es-tablished for the liquid pre-cooling process of a certain horizontal LNG pipeline.ANSYS software is used to analyze the influence of different liquid level relative heights on pipeline temperature,stress and deformation distribution under non-full liquid conditions.The simu-lation results show that the relative height of the liquid level directly affects the overall temperature distribution of the pipeline.The higher the relative height of the liquid level,the larger the lower surface area of the pipeline,and the smaller the upper surface area.The maximum average temperature difference between the upper and lower surfaces of the pipeline shows a trend of first increasing and then decreasing as the relative height of the liquid level increases.When the relative height of the liquid level is 40％,the maximum average temperature difference between the upper and lower surfaces of the pipeline is 45.79 ℃,and the maximum local temperature difference is 66.06 ℃.The trend of local temperature difference change is the same as the maximum average temperature difference.The maxi-mum stress peak at different liquid level relative heights occurs at 60％ of the liquid level relative height,which is 305.19 MPa.The stress peak occurs at the bottom of the inner wall at both ends of the pipe-line.As the relative height of the liquid level increa-ses,the peak stress first rapidly increases and then slowly decreases.As the relative height of the liquid level increases,the radial deformation at different posi-tions of the pipeline first increases and then decreases.The maximum radial deformation occurs at a relative height of 40％ of the liquid level,with a maximum ra-dial deformation of 68.753 mm.The variation curve of the maximum total deformation with the relative height of the liquid level is similar to the trend of the maxi-mum average temperature difference between the upper and lower surfaces of the pipeline with the relative height of the liquid level.The maximum average tem-perature difference between the upper and lower sur-faces of the pipeline with relative liquid levels of 10％and 90％ is very close,and the same applies to the working conditions with a relative liquid level of 20％and 70％,and a relative liquid level of 30％ and 60％.The temperature load exerted by LNG on pipe-lines at different liquid level relative heights is similar,and the temperature load is the main reason affecting pipeline deformation.It is recommended to further re-duce the liquid level relative height of the pipeline dur-ing LNG pipeline pre-cooling,and appropriately extend the pre-cooling time to reduce pipeline deformation caused by stress loads.
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NSTL
万方数据
维普
