Erosive Burning of Solid Rocket Propellants-A Revisit

A solid-propellant rocket motor test that exhibited unexpected erosive burning led to an extensive literature review of the subject. A qualitative theory that explains why higher burning-rate propellants are less prone to erosive burning, why propellants with similar burn rates have similar erosive behavior, and why erosive burning decreases as motor size increases evolved. The decrease in erosive burning with increasing motor size is caused by a decrease in the gas velocity that causes turbulence at the flame zone. This is predicted based on equations for the developing laminar boundary-layer velocity profile on a flat plate in compressible flow. The erosive burning data in the literature correlate well with the specific mass velocity, and useful equations for the ballistician are provided.