Release of high-pressure hydrogen from type III tank in a fire scenario: Analysis and prediction of jet flame length and thermal response characteristics

In this paper, the thermal response and jet flame behaviour of a typical type III high-pressure hydrogen storage tank with nominal working pressure (NWP) and volume of 70 MPa and 48 L were analysed at fire scenarios. The tank was discharged at a critical internal pressure 77.4 MPa, which was ca. 110 % of NWP. The pressure drop rates of type III tanks were greater than 1 MPa/s during the initial 15 s after venting. The length and width of jet flame were 4.93 and 1.65 m at the critical moment, which fluctuated downward over time. A thermokinetic model was employed to predict the variation of hydrogen gas state parameters and the maximum length of jet flame. The calculation results indicated that the maximum flame length of hydrogen released from a valve of 2 mm was around 2–6.5 m under a pressure range of 10–80 MPa. The error between the predicted results and the experimental values was less than 5 %. It was found that the flame length was enlarged by an increase of aperture. The length of flame increased by 6 m after the aperture changed from 2 to 5.08 mm at the equivalent pressure.