Combustion of solid-propellant charges with highly progressive gas release

The problem of the burning of structural configurations ensuring highly progressive gas-release is solved. Cylindrical, mushroom-like, and toroidal configurations are considered. Solutions are obtained in the form of quadratures or elementary functions. It is shown that in all the cases considered, not only the first but also the second derivative of the burning surface as functions of the amount of the burnt vault are positive. The increase in burning surface as a function of the length of the burnt vault is nonlinear in all cases, and it can be more rapid than a quadratic parabola (for spiral cylindrical and mushroom-like charges).