Self-ignition and flame propagation of high-pressure hydrogen jet during sudden discharge from a pipe

Experimental and numerical study on spontaneous ignition of hydrogen and hydrogen-methane jets in air

“…One of the possible reasons for this stochastic ignition feature is different membrane breaking process which affects the initial turbulence conditions of the flow. Similar behaviour has already been recorded by several researchers [3,4,6,8,9]. It was also observed that for burst pressures up to 16.0 MPa and 25 mm tube length, ignition did not occur for any investigated diameter.…”

Self-ignition of hydrogen–nitrogen mixtures during high-pressure release into air

“…In general, the above scheme of the single experiment with ignition was similar for pure hydrogen and hydrogen-nitrogen mixtures releases. The ignition if occurred was recorded by both photodiodes and ion probes therefore there were no single experiment with 'failed ignition' -quenched ignition shortly after leaving the tube as it was observed with hydrogen-methane mixture [26] or for pure hydrogen release reported in the literature [4,10,11,14].…”

“…In recent years one could observe an increased interest in hydrogen technologies and safety issues corresponding to them, including uncontrolled ignition during discharge into the air from high-pressure installations. Latest experimental [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] as well numerical [19][20][21][22][23][24] works focus mainly on the detailed description of the self-ignition mechanism according to different initial and boundary conditions including: extension channel geometry: diameter [4][5][6][7]19], length [5][6][7][8][9][10][11][12][13][14][15][16][17][20][21][22], cross-section shape [7,8,18,23] or obstacle presence in front of the hydrogen stream [18,…”

“…However, the results obtained by the researchers using the same experimental stands but applying different geometrical configurations (i.e. Mogi et al [4,10], Oleszczak and Wolanski [7]) group in particular diagram areas. There could be no clear quantitative conclusion regarding extension tube cross-section shape (rectangular or circular) or tube diameter influence on the selfignition propensity.…”

A Hydrogen Ignition Mechanism for Explosions in Nuclear Facility Piping Systems

“…For the explosion mechanism discussed here, a run-up length is not expected to be applicable. In other work, Mogi, et al [7] have shown that hydrogen oxygen gas mixtures will ignite when discharged through a tube to atmosphere at supersonic velocities.…”