Effect of Al-made burst disk on the shock wave and the spontaneous ignition of high-pressure hydrogen during its sudden discharge

Abstract

Hydrogen is regarded as the promising energy carrier in the next decades. However, the spontaneous ignition of pressurized hydrogen is one of the safety hazards blocking its safe utilization. In this paper, effect of the Al-made burst disk on the shock wave and the spontaneous ignition of high-pressure hydrogen is experimentally studied and discussed in detail through comparison with the previous results when Ni was used as a material. Pressure transducers and light sensors are employed to detect the shock wave and spontaneous ignition respectively. It is found that shock intensity, i.e., shock pressure and shock speed, decreases with the use of Al. As a result, the minimum burst pressure increases from 4.09 MPa for Ni to 4.51 MPa for Al. The result of the estimation of burst disk opening time and pressure profiles inside high-pressure storage tank prove that the opening time of Al is longer than Ni, which causes the wider hydrogen/air mixture area. The distance L between the contact surface and the leading shock wave increases with the increasing of Mach number, results in the short distance between contact surface and the leading shock wave for Al. After the mixing of cold hydrogen and heated air with high temperature that is close to the leading shock wave, spontaneous ignition occurs early inside the Al-made tubes.