Mathematical Model of a Two-Temperature Medium of Gas–Solid Nanoparticles with Laser Methane Pyrolysis

A mathematical model of a two-phase chemically active medium of gas and solid ultrafine particles in the field of laser radiation with detailed heat transfer processes between the gas and particles is created. The mathematical model is a system of Navier–Stokes equations in the approximation of small Mach numbers and several temperatures, which describes the dynamics of a viscous multicomponent heat-conducting medium with diffusion, chemical reactions, and energy supply through laser radiation. A computational algorithm is developed for studying chemical processes in a gas–dust medium with the single-velocity dynamics of a multicomponent gas under the laser radiation. This mathematical model multiscale, i.e., is characterized by the presence of several very different temporal and spatial scales. The computational algorithm is based on the scheme of splitting by physical processes. For a two-phase medium of a multicomponent gas and nanodispersed solid particles, theoretical studies of multidirectional processes of thermal relaxation and specific heating-cooling of the components of a two-phase medium by laser radiation, thermal effects of chemical reactions, and intrinsic radiation particles are carried out. It is shown that laser radiation can form a significant gap between the particle temperature and the gas temperature and provide the activation of methane with conversion to ethylene and hydrogen. The developed numerical model will find its application in the creation of new technologies of laser thermochemistry.