Numerical solution of the problem of surface combustion on flat porous matrix

The nature of the upper limit of surface combustion on a flat porous matrix was investigated with the use of numerical simulation. A one-dimensional stationary problem is solved with the use of global kinetic mechanism, which was previously tested at simulation of self-ignition and laminar flame propagation of paraffin hydrocarbons. It was established that the intensity of the heat exchange between the gas and the solid matrix material greatly influence the position of the flame front relative to the working surface of the matrix. The dependence of the combustion limits on the specific power has been revealed. It was shown that the appearance of the upper limit of surface combustion on a flat porous matrix is connected with the flame blowing off from the matrix surface, whereas limiting value of specific firing rate of combustion increases with the increase of methane-air mixture preheating temperature. However, at high preheating in intermediate range of specific firing rate the region of "unstable" combustion arises. The temperature of the working surface of the matrix is determined as a function of the specific firing rate.