Research On Ultimate Bearing Capacity Of Cryogenic Liquid Hydrogen Cylinder

The rapid development of society is becoming more and more dependent on energy.The reserves of fossil energy such as coal and petroleum are limited and non-renewable,and they will have the effects of smog,particulate matter and greenhouse effect,which is not conducive to environmental protection.Hydrogen energy has received extensive attention because of its non-pollution,renewable and other characteristics.It has become a strategic choice for optimizing energy consumption structure and national energy security,and has attracted some countries to start researching cars powered by hydrogen energy.In particular,vehicles using liquefied hydrogen as an energy source are hot research topics.Studying the structure and performance of liquid hydrogen cylinders provided for liquid hydrogen energy vehicles is of great significance for the safe use of hydrogen energy.Liquid hydrogen is cryogenic in temperature.If the temperature rises,gasification will cause the internal pressure of the gas cylinder to rise rapidly and quickly evaporate to form a flammable and explosive mixture of air when a leak occurs.Therefore,the safety of liquid hydrogen is very important.The main research object of this paper is the cryogenic liquid hydrogen gas cylinder.The gas cylinder has a double-layer structure.The inner tank is mainly made of 316 L stainless steel with excellent low temperature performance,the outer shell material is made of S30408 stainless steel material,and a high vacuum multilayer insulation is used between the inner tank and the outer shell.Because the risk and cost of the ultimate bearing capacity test of liquid hydrogen-containing medium are relatively high,this study used numerical simulation to study the ultimate bearing capacity of cryogenic liquid hydrogen gas cylinders.In this study,the numerical simulation method was used to study the bearing capacity of cryogenic liquid hydrogen cylinders.The established threedimensional numerical models of the outer shell,inner tank and rear-end support structure were used to predict the ultimate bearing capacity of the cylinder by using finite element calculation.The research results are as follows:(1)A numerical simulation model of the inner tank of a gas cylinder was established.The ultimate load method and the elastoplastic analysis method were used to analyze the inner tank of the gas cylinder to predict the ultimate load of the inner tank.Because the ultimate load method does not consider plastic strain,the predicted value is less than the predicted value of elastoplastic analysis considering material hardening.The simulation results show that the structure meets the engineering needs.(2)A three-dimensional numerical model of the outer shell of the gas cylinder is established,and its stability analysis is performed.Through linear and nonlinear buckling analysis,the number of wave and the critical instability load of the outer shell during instability are calculated.The simulation results show that both the critical linear buckling load and the nonlinear critical buckling load meet the engineering design requirements.(3)A new type of cryogenic gas cylinder rear-end support structure is proposed.Through carrying capacity analysis and steady-state thermal numerical simulation analysis of the structure,the simulation results show that the structure has good load-bearing capacity and thermal insulation performance.Compared with the current cross-shaped rear-end support structure,the new structure can reduce the heat leakage rate of the gas bottle,and can meet the load capacity requirements.The simulation research results in this paper show that the ultimate bearing capacity of this type of gas cylinder structure meets the safety and use requirements,which can provide a reference for the actual manufacturing process and help to promote the development process of liquid hydrogen cylinder.