Role of Condensed Phase Details in the Oscillatory Combustion of Composite Propellants

The response functions of composite propellants are theoretically derived, including explicitly the pressure-dependent degradation term in the condensed phase, hypothesizing that the overall rate-limiting reactions are in the relatively low temperature condensed phase. The method of "inner" and "outer" expansions with the reduced activation energy as the singular perturbation parameter has been employed. The results cover subsurface reactions with and without surface reactions, adiabatic and uniform-combustion models for the quasisteady gas phase processes. The response functions display several experimentally observed features like dependence on mean pressure and the instability behavior of some "zero-n" propellants.