Study On The Design Of Hydrogen System And Numerical Simulation Of Hydrogen Leakatge In Fuel Cell Passenger Ship

In recent years,the green ship using clean energy as fuel becomes one of the main directions for the development of the shipbuilding industry.The fuel cell ship combining hydrogen and green ship together has the advantages of low emission,high efficiency,high energy density,high reliability and low noise,which will contribute to the development of non-polluting shipping and energy sustainability in the future.But most studies about fuel cell ship have been limited in the hybrid power system and energy management strategies now.On the contrary,hydrogen safety which is special for fuel cell ship is rarely studied.There are so many risk factors in a fuel cell ship,including a large amount of hydrogen,complex hydrogen supply pipelines and some almost completely closed cabins.A horrible fire or explosion will take place when hydrogen leakage happens,that can cause very serious consequences for a passenger ship with much people and no rescue on the water.Therefore,how to recognize the danger in fuel cell ship and improve its hydrogen safety is one of the most urgent problems to be solved,also the goal of this study at the same time.In this thesis,a typical fuel cell passenger ship is selected as the research object.The studies on hydrogen system are carried out from a design perspective.Also,the studies on hydrogen leakage,dispersion and explosion in ship cabin are carried out by numerical simulation.So,the probability of fire or explosion accident can be reduced,and the consequences of the accident can be recognized.Some research findings can contribute the design,management and surviving to improve the safety in fuel cell ship.Furthermore,based on research project and conditions,a hydrogen fuel cell testing boat is developed,which is the foundation for the experimental research of fuel cell ship.The main research work and innovations are as follows:(1)Hydrogen system in fuel cell passenger ship is designed.For the target ship,the fuel cell system,hydrogen supply system and hydrogen safety system are designed respectively,based on the regulations and standards of hydrogen and ship.The storage of hydrogen,installation and arrangement of cylinders,design of pipes and valves,volume flow of hydrogen supplying and other key technologies have been studied in detail.(2)Hydrogen leakage and dispersion in cabin are simulated.Aiming at the layout features of the target ship cabin,the geometric model is established.Based on the gas leakage and diffusion equations,the transient leakage and diffusion processes of hydrogen in ship are simulated by commercial software Fluent.The distribution law of hydrogen concentration and dispersion trends are analyzed under different leakage conditions.The design suggestions for cabin ventilation system and the emergency measures are put forward.(3)Hydrogen explosions in cabin are simulated.Based on the gas explosion model,the explosion processes are simulated by Fluent when hydrogen gas is ignited in different cabins including the fuel cell room,control room and passenger cabin after the hydrogen leakage.The overpressure and temperature brought by explosion are analyzed.Based on the hazard assessment criteria,the direct consequences of the hydrogen explosion on personnel and vessels are assessed.On this basis,the countermeasures against the fire or explosion accidents in fuel cell passenger ship are put forward.(4)A hydrogen fuel cell testing boat is developed.Aiming at an inland small boat,a marine propulsion system with hybrid power sources of fuel cell,lithium battery and supercapacitor is put forward.The detailed work includes the design of power system and hydrogen system,selection of equipments,installation and arrangement,test and so on.