Peculiar Traits of Coarse AP
Abstract
Through various environments a factor influencing AP chemical activity is the propensity of coarse AP to produce porosity formation within its crystals. Porosity formation in coarse AP seems similar although at differing rates due to pressure and temperature influences in both isolated crystals and solid propellant combustions. Consolidated coarse AP crystals appear to be chemically unstable so that pure consolidated crystals cannot be made. Natural and accumulated trace impurities are responsible for observed porosity formation. In combustion environments kinetic action rates for coarse AP can be altered by materials on crystal surfaces and within the crystal bodies. Since orthorhombic crystal AP reaction rates are much faster in combustion environments than cubic crystal AP, orthorhombic phase AP is a primary actor during combustions. At very high pressures AP self combustion exhibits differential recession rates depending on whether surface regression is normal or transverse to the principal axis of its orthorhombic crystal structure. This behavior might be described as biaxial burning. Coarse AP oxidizer has observable chemical interactions that have not been observed for fine AP oxidizer during thermal decomposition and combustion environments. Coarse AP oxidizer has widely different chemical kinetic reaction rates between low and high heat fluxes. Widely different reaction rates are also observed between low and high pressure confinements. In solid propellants coarse AP promotes dark zone combustion, low burn rate pressure exponent, ease of burn rate adjustment, burn rate pressure exponent slope break, and slow cookoff violence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2014
- Accession Number
- ADA617861
Entities
People
- Claude E. Merrill
Organizations
- Air Force Research Laboratory