Dynamics of propellant ignition
Time dependent processes of solid propellant deflagration are modeled and a numerical simulation of ignition, extinguishment, and reignition is undertaken. Combustion is induced by the application of energy (i.e. radiation) to the moving gas/solid interface until steady conditions are achieved. Extinction can be induced by suddenly terminating this energy source- a process often referred to as deradiative extinction. An activation energy asymptotic theory for deradiation is developed for a Denison and Baum-type model. This predicts that an influx of radiation on the order of the steady heat release of the exothermic reaction will extinguish the propellant. This result is further confirmed by computer simulation of more complicated situations than are accessible to the theory. The inclusion of low activation energy radical reactions can reverse this result and, after a short pause subsequent to the deradiation event, the propellant will reignite. The reason for this behavior lies in the inventory of radicals acquired between the gas/solid surface and the end of the gas combustion zone during the period of radiative heating. These radicals contain a considerable amount of chemical energy as well as the ability to participate in chain propagating reactions at the considerably lower temperatures created by the deradiation event. These circumstances allow the propellant to recover from the extinguishment and continue burning.
- OSTI ID:
- 5128071
- Report Number(s):
- CONF-870484-
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ACTIVATION ENERGY
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COMBUSTION PRODUCTS
COMBUSTION WAVES
ENERGY
ENERGY TRANSFER
FLUID FLOW
FUELS
HEAT TRANSFER
IGNITION
KINETICS
MATHEMATICAL MODELS
PROPELLANTS
RADICALS
REACTION KINETICS
SOLID FUELS
THERMODYNAMICS
TWO-PHASE FLOW