Gaseous detonation propagation in a thin channel with regularly spaced cylindrical obstacles was investigated experimentally and numerically. The wave propagation with substantial velocity deficits is observed and the details of its propagation mechanism are described based on experimental measurements of the luminosity and pressure and on three-dimensional flow fields obtained by numerical simulations. Both experiments and simulations indicate a significant role of shock–shock and shock–obstacle interactions in providing high-temperature conditions necessary to sustain the reaction wave propagation.

Acetylene is characterized by high reactivity and appears to be one of the promising gas fuels. However, possible combustion regimes of such fuels require a comprehensive study to be widely introduced in practice. This work is devoted to analyzing the modern kinetic mechanisms of acetylene oxidation. Current approaches to numerical analysis of the gas-dynamic flows in chemically active gas mixtures are a powerful tool in solving many industrial and energy problems. Obtaining positive results of numerical simulation of the non-stationary combustion and detonation processes is impossible without the use of reliable and efficient kinetic mechanisms. Kinetic mechanisms were considered describing the acetylene oxidation. Eight most optimal mechanisms were studied to identify the possibility of their implementation in detailed simulation of the non-stationary combustion processes, in particular, in flame acceleration and transition to detonation. Ignition delay time and laminar burning velocity were calculated using a complete model of the reacting medium gas dynamics. To evaluate correctness of the ignition and combustion parameters obtained values, they were compared with the available experimental data. Based on the obtained results analysis, conclusions were made on the possibility of applying the kinetic mechanisms under consideration, taking into account the combustion parameters accuracy and the computational efficiency

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Flame acceleration (FA) and the deflagration-to-detonation transition (DDT) are among the most interesting and exciting phenomena in the field of combustion and explosion of gases. From both practical and theoretical points of view, it is important to understand the basic laws governing these phenomena as well as the physical and/or chemical mechanisms and features of the process. High-speed flame-front photography during the deflagration of a premixed gas mixture in a long smooth tube with transparent walls was performed. A stoichiometric mixture of acetylene with oxygen diluted with argon by 25% is used. The experiments are carried out in a transparent cylindrical tube with an inner diameter of 60 mm and a length of 6 meters. The evolution of the structure and shape of the flame front from the moment of initiation of deflagration by a weak ignition source to the formation of a detonation wave is determined. Four characteristic phases of the propagation process are distinguished: at the first stage, the flame accelerates, then slows down, followed by flame propagation at an almost constant speed, and finally repeated acceleration, during which detonation is formed. It is shown how the dynamics of the process changes with a change in the initial pressure of the mixture. The most interesting and poorly studied stage of the DDT, the stage of intensive reacceleration, during which the flame abruptly changes shape, is described in detail.