Model Describing the Erosive Combustion and Velocity Response of Composite Propellants

A detailed model is presented which permits one to represent the response of the burning rate of an ammonium perchlorate solid composite propellant to pressure and velocity fluctuations. First, the steady regime response of the burning velocity of a propellant exposed to a turbulent boundary layer is described. The well-known granular diffusion flame model is employed, with the changes in the transport coefficients taken into account. It is shown (and not assumed) that, according to the present model, an additive law applies; a pressure and velocity sensitive erosive component is added to the normal pressure sensitive burning rate. By coupling the unsteady behavior of the propellant solid phase to the quasisteady flame zone, represented by the abovementioned model, the linearized response of the propellant to pressure and velocity oscillations is obtained.