Numerical Simulation And Experimental Study On Failure Process Of Dome Roof Oil Tank Under Pool Fire Scenario

Vertical dome roof storage tank is widely used in oil storage,large volume,small rigidity,is one of the most common tank type.The oil stored in the storage tank is flammable and explosive.In industrial production,there is a risk of oil leakage or explosion in fire,which can easily cause safety accidents.Pool fire is a common type of fire caused by failure of oil storage tank.When the tank is surrounded by pool fire,the high temperature flame radiates and convective heat transfer to the tank wall.The thermal invasion will cause the tank material failure,and the internal pressure will gradually increase with the increase of medium temperature.When the pressure growth speed is greater than the relief speed of the safety valve,the oil storage tank is in danger of overpressure failure.Once it breaks,it is easy to cause boiling liquid expansion and steam explosion,which will pose a great threat to the safety of rescue personnel and nearby oil tanks.The failure process of oil storage tanks in a fire environment is complicated.The failure mechanism of oil storage tank is deeply explored,and the failure time is scientifically predicted,it is of great significance for rescue workers to provide safety warning and prevent disaster accidents.This paper mainly studies the dynamic failure process of vertical vaulted storage tanks with"weak roof structure"under pool fire.The specific work is carried out from the following aspects:(1)A two-dimensional finite element model of 5000m~3 vertical dome roof tank is established to simulate the thermal response of the tank with 85%filling level,the temperature and internal pressure changes of storage tank are analyzed to provide data support for dynamic failure analysis.(2)A three-dimensional finite element model of 5000m~3 vertical dome roof storage tank with"weak roof structure"is established to simulate the thermal structural coupling of the tank under pool fire environment,the stress and temperature changes in the dynamic failure process of the storage tank are analyzed,and the first failure position is observed to verify whether it meets the"weak roof structure"design.The influence of different flame temperature and filling level on tank failure process was analyzed.(3)The failure experiment of"weak roof structure"was designed,and the hot tensile test platform was built.Considering the actual stress of tank weak roof structure under high temperature environment and the limitation of experimental platform,Simplified stress,the vertical and horizontal specimens with weak connection are made,and the influence of temperature on the failure of weak connection structure is analyzed.Based on LS-DYNA,the tensile failure process of the specimen was simulated and compared with the experimental results.(4)Aiming at the phenomenon of creep low cycle thermal fatigue of storage tank in fire environment,n Code Design Life fatigue software is used to analyze the creep-low cycle thermal fatigue damage of storage tank in fire environment.The influence of creep damage and fatigue damage on the failure is compared,and the fracture failure mechanism is revealed.