Abstract. In the gas explosions simulation practice in non-closed areas there is a common opinion of burning rate increase at turbulization of initial gas mixture stream. The article shows that in conditions of turbulization there is no increase of the burn rate, but of the flame front area. A wording change of pressure rise reason does not lead to a change of the calculation results, but gives the opportunity to look at the problem differently and interpret a physical process correctly. In order to prove it there are results of the vibrational combustion modeling in terms of gas explosion in the cylinder with an opening on the side. The results show that along with the pressure fluctuation there is burning area size fluctuation that occur synchronous and with the same amplitude. The modeling basis is the system of differential equations, that describe the adopted in gas dynamics fundamental conservation laws, the equation of state, written in the so-called Euler's form. The system is supplemented with flame spread conditions. The system solution is based on the Russian method of the numerical approximation of this system-the large-particle method.

Introduction. There are known cases of fires after gas explosions in domestic residential premises, exacerbating an already dangerous situation. Determining the conditions for the occurrence of such fires, as well as the process of behaviour of combustible materials during the short-term thermal effect of a gas explosion, allows us to hope for the possibility of reducing fire risks through research and the development of appropriate measures. Methods Experimental studies were carried out in a cubic chamber with a volume of 10 m3 filled with a propane-air mixture. Explosion pressure and video inside the chamber were recorded. To assess the magnitude of the effects of flame and combustion products of a gas explosion on combustible material, specially developed indicators with a sensitive element – sheet of paper. Results. The images of sensitive elements of indicators with the level of brightness after exposure to a flame and combustion products of a gas explosion are presented. Frames from a video camera installed inside the camera are also presented. Discussion. The conditions for ignition of combustible materials are: low heat capacity, position in the volume of premise and the entry of outside air. Conclusions. It is established that combustible materials in the corners of premise are less affected by the flame and combustion products of a gas explosion. Combustible material ignites when external air enters after an explosion.

The possible existence of acoustic oscillations (oscillating combustion) in gas explosions in unclosed volumes is known. A significant increase in risks was confirmed, if it happens indoors, which makes studies in this direction relevant. But the solution to this problem has proven difficult for two reasons. First, the results of the experimental studies turned out to be reproducible with weak reliability. This circumstance takes place, despite the fact that the first classical experiments, resulting in acoustic oscillations during gas heating, date back to the 19th century. The second reason why research is difficult is that by now there are no reliable mathematical models describing the process of excitation and development of oscillating combustion in gas explosions. The gas explosion simulation using the example of cylindrical chamber with a diameter of 200 mm and a length of 1.5 meters and a window on the lateral surface. The chamber in the initial state is filled with propane-air mixture, which is ignited at the left end along the chamber axis. The validity of mathematical model was checked by comparing the results of the gas explosion development calculation in the tube with other known results obtained in the closed circular tubes.

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