Seismic Response Analysis Of LNG Storage Tank Considering Temperature Effect

In the process of transformation and upgrading of China’s energy structure,natural gas plays an indispensable role.As an important device for cryogenic liquefied natural gas storage,the safety,stability and durability of LNG storage tank have always been the focus of attention.The earthquake often leads to the rupture of LNG storage tanks and the leakage of cryogenic liquids,endangering the safety of people’s lives and property.The coupling between fluid domain,solid domain and temperature field was rarely considered in previous seismic response analysis of LNG tank.In this paper,the coupling of thermal-fluid-solid field under LNG tank leakage condition was considered.The specific contents are as follows:(1)Introducing the theory of thermodynamics,the theory of fluid-solid coupling and the relevant theoretical models,establishing the thermal-structural coupling model of each part of LNG storage tank and the integral thermal-fluid-solid coupling model of LNG storage tank respectively by the finite element software,the correctness of the model is verified.(2)Based on the thermal-structural coupling,the distribution of temperature field and stress field of tank bottom,tank wall and suspended ceiling under normal working condition is investigated by changing the ambient temperature only under the control of other conditions,by analyzing the change of temperature and stress in different material layers,it is concluded that the change of temperature in nickel steel layer and concrete layer is little,but the change of temperature in insulating layer is great,the temperature of the concrete layer is almost consistent with the ambient temperature,which shows that the insulating layer can prevent the heat loss in the tank and keep the temperature in the tank at a constant level.(3)Based on the thermal-structural coupling,the temperature field and stress field of the outer tank under the leakage condition of the inner tank of LNG storage tank are analyzed under four different liquid level heights: Empty Tank,1/4 tank,half tank and full tank,the distribution of temperature field and stress field under different thickness of concrete layer is investigated.It is concluded that the temperature distribution below the leaking liquid level does not change with the liquid level,the temperature distribution above the leaking liquid level will change.The influence of the thickness of concrete layer on the temperature distribution is mainly concentrated in the concrete layer,and the temperature at the insulating layer is hardly affected when the ambient temperature changes under different thickness of concrete layer,but the temperature changes greatly in the concrete layer.(4)Based on the thermal-fluid-solid coupling,the vibration characteristics and the distribution of acceleration,stress and displacement of LNG storage tank are investigated by time-history analysis method under different seismic waves and different seismic directions,the influence of temperature and fluid-solid coupling on the seismic response of LNG storage tank is obtained,and the most disadvantageous position and corresponding damage form of LNG storage tank under seismic action are analyzed.