It was shown that maximum pressure and maximum acoustic intensity are much greater for the obstacle with several openings as compared with the obstacle with single opening. It was shown that both minimum pressure of flame penetration and minimum diameter of an opening, through which the flame of the diluted methane-oxygen mix can penetrate decrease with an increase in the number of openings. Numerical calculations based on low Mach number approximation of the compressible reactive Navier-Stokes equations showed good qualitative agreement with experimental results. It was concluded that at assessment of a fire safety of the room or confinement with several openings one should not use the value of the minimum size of the single opening, because at an increase in the number of openings the size sufficient for flame penetration decreases.

In experiments on 2H2 + O2 ignition over palladium and platinum at total pressures up to 200 Torr at initial temperature up to 300° C, the temperature of the foils during ignition was measured by means of both infrared camera and an acquisition system accounting for the temperature dependence of the metal resistivity. It was shown that the temperature of the initiated ignition at 40 Torr over heated palladium foil is ~ 100° C lower than over platinum foil. It is shown that even the minimum temperature value (623° C) is already enough to ignite a stoichiometric hydrogen-oxygen O2 mix, i.e. the influence of a catalytic hydrogen oxidation reaction over the noble metals is negligible in case of initiated ignition. However, the presence of water vapor prevents ignition. For thermal ignition, it was found out that at pressures up to 180 Torr at 288° C over palladium foil as compared to platinum foil the catalytic activity of the surface is high. The activity of palladium foil expresses itself both in the occurrence of local ignition centers on the foil, from which combustion wave propagates and in the dark catalytic reaction of consumption of the flammable mixture.

It is experimentally shown that the flame of methane-oxygen mix does not get through the central opening of a confuser up to the opening angle of 83 0 , but gets through the central opening of the diffuser, despite of the existence of additional openings on cone elements. The results of numerical modeling with the use of the equations of Navier-Stokes in the compressible reacting environment in acoustic approach allowed to describe qualitative features of flame propagation through an obstacle of conical shape with additional openings on cone elements.