Combustion and the transition to detonation in a gas mixture in a closed space

The possibility of going from deflagration to detonation in mixtures of СН$_4$ + 2(O$_2$ + $\beta$N$_2$) and 2Н$_2$ + O$_2$ + $\beta$N$_2$ (0 $\le\beta\le$ 3.76) was investigated experimentally in a space enclosed by various combinations of three thin-walled metal concentric turbulator-sphere (diameters in a ratio 1:2:4) with large numbers of openings (permeability 0.1–0.4). Transition from deflagration to detonation was observed for $\beta\le$ 1 in the first mixture and for $\beta\le$ 3.2 in the second.