| Hydrogen energy has the advantages of high energy density,high burning heat value,wide source,zero pollution,zero emission,and so on.It is recognized as a clean energy.Hydrogen has lower lower limit of explosion,larger limit of explosion,and smaller ignition energy.In the process of hydrogen production,storage,transportation,and use,there are certain risks of leakage and explosion.Safety is an important factor affecting the popularization and application of hydrogen energy.Based on this,by means of large-scale test in fire environment,computational fluid dynamics simulation,and theoretical research,the temperature and pressure response characteristics and explosion shock wave propagation law of high pressure hydrogen cylinder used in vehicle with carbon fiber wound aluminum liner under fire condition were studied.Explosion hazards were quickly assessed.The main work contents and conclusions of this paper are as follows:(1)Experimental study on the risk of high pressure hydrogen storage tank used in vehicle under fire condition.Large-scale burning experiments of 35 MPa and 70 MPa high-pressure hydrogen cylinders in fire environment were carried out.The temperature response law of the outer wall and the internal pressure response law of the high pressure hydrogen storage tank under the condition of fire were studied.The explosion risk of high-pressure hydrogen cylinders was further discussed by changing the volume of the test object.Experimental studies show that: In different stages of ignition,partial combustion,overall combustion,and pressure relief/explosion,the variation of wall temperature and pressure in the cylinder was different.In the comparison of three kinds of 35 MPa high-pressure hydrogen cylinders with different volumes,the time required to boost the pressure by 5% and 10% appeared to lengthen with the increase of volume.(2)Numerical simulation of the risk of high pressure hydrogen storage tank used in vehicle under fire condition.Fluid-solid conjugate heat transfer model and explosion shock wave model were established.The change law of the wall temperature,internal temperature and pressure of the high-pressure hydrogen storage cylinder before thermally activated pressure relief device(TPRD)activation,as well as the explosion shock wave propagation and explosion shock wave overpressure of the high-pressure hydrogen storage cylinder when TPRD failure were analyzed in detail.Numerical simulation studies show that: During the burning process,the temperature of the shell,inner tank,and hydrogen of the high pressure hydrogen bottle had different variation rules and spatial distribution characteristics.At 180 s,it was the relatively safe golden time for local burning of the 53L-35 MPa high-pressure hydrogen storage tank.In the case of ignoring the effect of the cylinder wall in the explosion process,the flow field in the xy-plane presented a uniform and regular symmetrical structure on the whole.The front end of the explosion shock wave propagated in a spherical shape to all sides.The air near the explosion center was rapidly compressed to produce a negative pressure area,and the shock wave intensity near the ground was slightly enhanced.When the distance from the explosion center was closer,the propagation speed of the blast wave was faster.As the distance increased,the propagation speed decreased.(3)Rapid assessment of the risk of high pressure hydrogen storage tank used in vehicle under fire condition.A theoretical analysis system was established for the research object in the aspects of state equation,explosion index,and evaluation standard.Taking the proportional distance as the index,the prediction model of the explosion overpressure of high pressure hydrogen storage tank was established.A gas cylinder explosion risk assessment software was developed based on Web Storm development tool.It realized the rapid evaluation of the basic physical parameters of the cylinder,the overpressure of the explosion shock wave,and the dangerous area. |
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