Study of Hydrogen–Air Flame Propagation in a Flat Gap Using IR Visualization

The article presents an experimental study of the propagation of a hydrogen–air flame in a flat gap with central ignition. High-speed infrared visualization was used for the first time, which made it possible to examine in detail the initial stage of flame formation in a flat gap and to determine the structures formed during combustion of the mixture. During combustion of lean hydrogen–air mixtures, decay of the deflagration flame front was detected, leading to the formation of individual foci that spread radially. Note that this effect is observed only when the gap width is no greater than 5 mm and the volumetric hydrogen content in the mixture is no greater than 10%. The intensity of combustion product radiation is analyzed as a function of the mixture composition and width of the flat gap. The relevance of the study is governed by hydrogen energy safety requirements, in particular, the explosion safety of hydrogen fuel cells.