On the similarity and scaling for pulsed hydrogen release under high pressure into the unconfined space

The paper discusses the gas-dynamic similarity for the process of pulsed hydrogen release under high pressure into the unconfined space and the feasibility of process scaling in terms of hydrogen-air pressure ratio. The main distinctive feature of the considered process among a wide variety of the jet flows is the chemical reactivity. The hydrogen-air ignition affects flow development and causes break of the similarity. Nevertheless, as numerical analysis shows there is a certain range of parameters (initial pressure, size of the outflow opening, time of burst disc rupture) where the similarity is maintained. In view of this, there is a potential for experimental modeling of accidental scenarios under laboratory conditions using reduced air and hydrogen pressures. The paper presents a set of numerical data on the pulsed hydrogen release, physical interpretation of the studied phenomenon and recommendations for further experimental analysis of the accidents on hydrogen storage and transportation facilities.