Self-sustained regimes of liquid aerosol detonation

Abstract

Main problem of detonation theory, self-sustained regimes finding, is solved for liquid aerosols. Combustion modelling is performed at two scale levels, where the irreversible processes such as aerosol atomization, daughter droplets' evaporation and chemical energy release kinetics are represented at the lower scale. Instability of flow in conjugated boundary layers at drop surface is adopted as mechanism of aerosol atomization. Vapour mixing with oxidizer forms combustible moles, whose chemical induction times are calculated individually, so that the moles are stack-ordered. At the upper scale, equations of overall motion of two-velocity, two-temperature, five-component reacting medium are composed. Two key aspects of the main problem are considered: (i) detonation wave structure in stationary zone is calculated and analysed and (ii) self-sustained regime velocities are determined. The first reveals the existence of two mixture burning modes: explosive kinetic and smooth diffusive, which are separated by conclusive micro-explosion. The second shows the existence of only two front velocity values in aerosol system, at which the interphase processes provide fulfilment of Zeldovich's necessary condition. Explanation is found for incomplete burnout regime: it stands on specific balance between the rate ratio of physical-to-chemical processes, which is reached at such front velocity, when sonic state is attained exactly after the conclusive micro-explosion.