Nonlinear Phenomena and Kinetic Mechanism of a Gaseous Branching Chain Process by the Example of Thermal Decomposition of Nitrogen Trichloride

Abstract

The inhibition and promotion of non-thermal NCl3 flame by NOCl and H2, respectively, are explained. The crossover from the non-thermal mode of flame propagation to the thermal one is analyzed for NCl3–He mixtures. Calculations based on a kinetic mechanism taking into account energy chain branching are performed, and qualitative agreement between the calculated and observed data is demonstrated. Nonlinear chain branching shortens the time needed for thermal ignition and increases the flammability of the combustible mixture. It is shown that the mechanism of reaction of NCl3 decomposition proposed above is in good qualitative agreement with experimental data. It is established that the conditions sufficient to obtain oscillating solutions are the following: (a) accounting for adsorption—desorption of NCl3 on reactor walls, (b) accounting for nonlinear chain termination Cl + Cl2 3Пou → Cl + Cl2 1Σg −, (c) accounting for energy chain branching. Therefore, accounting for processes of desorption of NCl3 from the reactor surface during oscillations and the change in a surface state leads to the occurrence of the oscillation modes in a numerical experiment, which are in qualitative agreement with experimental data.