Filtration combustion of gases

Abstract

1. The process of filtration combustion of a gas in an inert porous medium has been carried out experimentally and investigated. The possibility is shown for the propagation of combustion waves counter to the flow and in the direction of the flow, and for the “standing wave” state. The significant role in the process of such factors as the flow velocity, heat content of the mixture, and the size of the elements of the medium is established. 2. A two-temperature model of the filtration combustion of gases has been constructed and validated which describes the effect of the parameters on the characteristics of the process. The model predicts, in particular, the existence of a temperature peak in the zone of chemical reaction and of the existence of anomalously low and high combustion temperatures. The theoretical conclusions coincide satisfactorily with experiment. 3. The presence of two regimes of filtration combustion of gases is established: low velocities with a strong thermal interphase interaction, and high velocities with a weak thermal interaction. The possibility is shown for the existence of limits of combustion wave propagation, due to thermal losses. 4. An important element of the mechanism of filtration combustion of a gas in the regime of low velocities is the recuperation of heat in the cycle: combustion products-porous medium-fresh gas-combustion products. In this case the thermophysical characteristics of the medium play a decisive role in the structure and propagation of combustion waves.