The Ignition Mechanism of Composite Solid Propellants
PRINCETON UNIV NJ DEPT OF AERONAUTICAL ENGINEERING
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Evidence points to gas phase heat evolution as the controlling mechanism for the steady-state deflagration process of solid propellants. Generally, this takes the form of a measured decrease of the ignition time lag with increasing oxygen concentration of the ignition gas. The study of this effect in the ignition of NH4ClO4 composite propellants is discussed. The shock tube was selected as the basic tool for this research. All of the quantitative experiments, designed to verify the gas phase ignition theory were executed by exposing small specimens of propellants to an instantaneous, controlled, heat input. This was accomplished by reflecting impinging shock waves from their exposed, flat, surfaces. As the igniting gas composition was vitiated with N the measured ignition time lags increased from a few hundred microseconds in a mixture of 100 O2, 0 N2, to 5 milliseconds in a mixture of 40 O2, 60 N2. This evidence led to an ignition mechanism based on a gas phase heat release due to the reaction between the vaporized fuel component of the propellant and the oxygen component of the ignition gas.
- Combustion and Ignition
- Solid Rocket Propellants