Full-scale tunnel experiments: Blast wave and fireball evolution following hydrogen tank rupture

In the framework of the HyTunnel-CS European project sponsored by Clean Hydrogen Joint Undertaking (CH JU), a number of tests were conducted in a full-scale tunnel in France. These tests are devoted to safety of hydrogen-fuelled vehicles having a compressed gas storage. The goal of the study is to develop recommendations for Regulations, Codes and Standards (RCS) for inherently safer use of hydrogen vehicles in enclosed transportation systems. Two sets of tests have been performed, (a) five tests with compressed hydrogen tanks, (b) two tests with compressed helium tanks. The hydrogen gas pressure varied between 47 bar and 610 bar. The blast wave overpressures are recorded together with fireball characteristics. The obtained experimental data are compared to existing engineering correlations and it is confirmed that not only the mechanical energy of compressed gas but also a fraction of chemical energy contribute to the blast wave strength.