Solid flame combustion of cylindrical samples with stepwise varying diameter

Unsteady propagation of a gasless combustion wave in a cylindrical sample with a stepwise varying diameter was studied numerically. For the diameter of the smaller cylinder which ignites the larger cylinder, the critical values for combustion extinction were calculated as functions of the Zel’dovich and Arrhenius parameters. At a diameter larger than the critical value, the combustion wave entered a semibounded volume of the reaction medium. The critical diameter was shown to be a characteristic of the reaction medium.