Instability of the front of filtration combustion of gases in the nonadiabatic regime

The instability of the stationary front of gas combustion in an inert porous medium in the nonadiabatic regime is studied using a one-temperature thermal model. A dispersion relation that does not coincide with the previously known equation is obtained on the basis of a formula for the equilibrium temperature in which the heat-transfer coefficient and gas injection rate are additionally taken into account. The boundaries of oscillatory and exponential instability are determined as the limiting maximum values of the heat-transfer coefficient to the surrounding space in the form of a dependence of the stationary combustion front velocity on the gas injection rate. The relation of determining parameters at the combustion limit was obtained by the Zel’dovich formula.