Ignition of AP-based composite solid propellants containing nitramines exposed to CO sub 2 laser radiation at subatmospheric pressures

Journal Article · Wed May 01 04:00:00 EDT 1991 · Combustion and Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(91)90177-D· OSTI ID:5092873

Saito, T; Shimoda, M; Yamaya, T; Iwama, A ^[1]

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1. Inst. of Space and Astronautical Science, 1-1, Yoshinodai 3-chome, Sagamihara City, Kanagawa Prefecture 229 (JP)

This paper investigates ignition characteristics of AP-based composite solid propellants that contained either HMX or RDX, using a CO{sub 2} laser at relatively low heat flux and subatmospheric pressures, in order to simulate space environments and also simplify our understanding of the nature of ignition phenomena. The results are presented graphically as a function of surface heat flux and ambient pressure. The ignition process was found to be roughly divided into two regions of self- sustaining ignition (S.S.I.) and non-S.S.I., depending on whether the ignition reaction is self-sustained or extinguished when the external radiation is interrupted after ignition. Furthermore, the non-S.S.I. was composed of two regions of radiation-assisted combustion (R.A.C.) and radiation-assisted unstable combustion (R.A.U.). The addition of nitramines, in particular HMX to AP-based composite propellants resulted in a marked reduction in the ignition times and made the self-sustaining ignition region shift to lower heat fluxes at each specific pressure. It was found, from the results of differential thermal analysis and thermogravimetry, that nitramine-containing propellants exhibit an exothermic decomposition at relatively low temperatures that is independent of the presence of other ingredients. This triggers the ignition reaction of the AP- based propellants and lowers temperature of the main exotherm. Consequently, it appears that the improvement of ignitability by the addition of nitramines is due to the intense low-temperature exothermic reaction of nitramines. It was found from the time-temperature histories measured with fine thermocouples on the surface during the ignition process that ignition temperatures also are lowered by the addition of nitramines.

• OSTI ID: 5092873
• Journal Information: Combustion and Flame; (United States), Journal Name: Combustion and Flame; (United States) Vol. 85:1; ISSN 0010-2180; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
100400 -- Synthetic Fuels-- Combustion-- (1990-)
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
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Pyrolysis
& High-Temperature Chemistry
AMINES
CARBON DIOXIDE LASERS
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COMPOSITE MATERIALS
DATA ANALYSIS
GAS LASERS
GRAPHS
HEAT FLUX
KINETICS
LASERS
LOW PRESSURE
MATERIALS
NITRO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PROPELLANTS
RADIATIONS
REACTION KINETICS
SIMULATION
SPACE TRANSPORT
TRANSPORT