Study of Combustion Processes of Single-Perforated Stick Propellants
PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF MECHANICAL ENGINEERING
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This paper addresses flame-spreading, combustion, and grain-rupture processes associated with unslotted single-perforated stick propellants, both theoretically and experimentally. A coupled finite-difference and finite-element code was developed for solving the property variations in gas- and solid-phase regions. Tests were conducted using a windowed chamber for observation of the transient combustion and fracture phenomena. Test data indicate that higher pressurization rate causes earlier propellant ignition and faster flame- spreading rate. Critical pressure differential across the propellant ignition and grain rupture was found to increase monotonically with the internal pressurization rate. Recovered propellant samples showed that longitudinal slits were formed at low pressurization rates, while at rapid pressurization rates higher than 3.5 GPaa, the grains shattered into many small pieces. Depending upon the internal pressurization rates, SEM microstructure of fractured surfaces of recovered grains exhibited ductile tensile, ductile shear, or brittle- cleavage phenomena.
- Ammunition and Explosives