Dynamics and energy of combustion of ultra-lean mixtures of hydrogen with air in a limited volume

In this paper, the combustion dynamics inside a closed volume filled with pre-mixed hydrogen-air mixtures with a composition close to the lower flammability limit is investigated based on a detailed numerical analysis. A comparison of flame evolution features is made depending on the initiation mechanism: a point ignition source or continuous heat supply from a heated region on the reactor wall. It is shown that with point ignition, the completeness of hydrogen combustion is significantly lower than with heat supply from the wall. It is also found that, despite the low chemical activity of ultra-lean hydrogen-air mixtures, the combustion process has a positive balance between the energy release during chemical reactions and the heat supplied to the reactor from the heated wall.