Research On Fire Resistance And Fatigue Performance Of Fully Wrapped Fiber Reinforced Al-lined High-pressure Hydrogen Vessels

As a secondary energy, hydrogen is considered to be the most development potential energy carrier in the 21st century because of its excellent properties such as high conversion efficiency, clean combustion product, low storage cost and renewable, etc.. Its applications in cars, trucks, buses, taxis, motorcycles and commercial ships have become the focus of many hydrogen energy research institutions. Hydrogen is a good choice to solve the two problems of the international community, which are "energy shortage"and "environmental pollution".Safe and efficient storage technique has become bottleneck of the further application of hydrogen energy. Nowadays, fully wrapped fiber reinforced high-pressure hydrogen vessel is excellent in high-pressure-resistant ability, light weight and corrosion resistance. It has currently become the preferred container for hydrogen storage in vehicles. The medium within the vessel is hydrogen which is flammable and explosive, and the safety performances of hydrogen storage vessels have become one of the most important factors for that hydrogen fuel cell vehicles are not yet widely accepted by the public.In order to accelerate the development and application of on board fully wrapped fiber reinforced Al-lined high-pressure hydrogen vessel in our country, researches on fire resistance and fatigue performance of fully wrapped fiber reinforced high-pressure hydrogen vessels are conducted in this paper. This research is supported by the key project of national programs for fundamental research and development of China (973 program, Number:2007CB209706) and the nonprofit industry research project of General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China (Number:10-131). The main contents and conclusions of this paper are as follows:(1) In order to verify the safety performance of fully wrapped fiber reinforced Al-lined high-pressure hydrogen vessels under fire conditions, bonfire test was carried out. The temperature distribution on the outer surface of the tested vessel and the rising of the pressure of hydrogen were obtained in the bonfire experiment. The experimental data provide support for the further systematic studies on the bonfire test methods of fully wrapped fiber reinforced high-pressure hydrogen vessels.(2) A 3D numerical model was established to simulate the heat transfer process of vessel wall during bonfire with the CFD software FLUENT. It is revealed that the temperature inside the vessel was far lower than the temperature at the vavle when the PRD was activated. Then a 3D numerical model for simulating the process of the bonfire test was developed based on the heat transfer model. The accuracy of the model was verified by the comparison between the experimental and simulation results. The model was employed to analyze the influences of test parameters on the temperature rising, such as fuel type, fuel flow, filling medium and filling pressure. Some proposals were presented on the basis of the simulation results. For the 74L,40MPa fully wrapped fiber reinforced Al-lined high-pressure hydrogen vessel, the flow should be larger than 400 NL/min if methane gas is used as fuel or larger than 150 NL/min when propane gas is applied. And the results show that the filling medium has little influence on the rising of temperature and pressure. So it is firstly proposed that air is suitable and acceptable to instead of hydrogen to pressure the vessel in bonfire test. The proposal has been accepted by " Hydrogen Fuel Cell Vehicle-Global Technical Regulations"(HFCV-GTR) and other relevant international standards (draft).(3) In order to study the high-pressure hydrogen jet flow, a 3D numerical model was established based on the species transfer model and SSTκ-ωturbulence model. It is revealed that under-expanded jets were formed after the high-pressure hydrogen discharging from the vessel. Then the mathematical methods were adopted to study the high-pressure hydrogen jet flames. The damage region of hydrogen jet flames were analysed and the safety distances for bonfire test of hydrogen storage vessels in open space were put forward. The effects of barrier walls on the distribution of jet flames were also studied. The results show that the barrier walls can greatly reduce the damage from hydrogen jet flames to testers and properties around. Based on the simulation results, precautions of hydrogen jet flames in limited space were proposed.(4) The ambient temperature pressure cycling test and extreme temperature pressure cycling test for fully wrapped fiber reinforced Al-lined high-pressure hydrogen vessels were carried out. According to the continuum damage mechanics (CDM) theory, a fatigue evaluation model was established. The stress of the vessel was simulated by finite element method. The fatigue lifetime can be predicted combining the fatigue evaluation model and the finite element method. By the comparison of the predicted fatigue lifetime and the experimental results, the proposed fatigue lifetime evaluation method is proved to be rational.