Abstract Hydrogen is a promising alternative to natural gas in industrial energy applications to limit global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). Most existing data on thermal radiation are based on unsteady flow conditions and/or still air, whereas the experiments carried out here ensure a constant mass flow under realistic free-field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Based on the investigations, empirical equations for modelling jet flames could be derived.
Bernardy et al. (Tue,) studied this question.