Mixing Hydrogen and Air in a Cylinder

The mixing of hydrogen and air is investigated experimentally by injecting hydrogen into air and vice versa. The modes of mixing are investigated at volumetric flow rates of the injected gas ranging from 5 to 50 L/min, final absolute pressures of the mixture ranging from 1 to 5 atm, and final hydrogen concentrations ranging from 10 to 60 vol %. When injecting hydrogen into air, characteristic periods of mixing range from 3 to more than 24 h. When injecting air into hydrogen, characteristic periods of mixing range from 1.2 min to 1.2 h. The measured periods of mixing are approximated using empirical formulas.