AMMONIUM PERCHLORATE-BASED PROPELLANT IGNITION BY LOW CONVECTIVE HEAT FLUXES
Abstract
The ignition response to convective heating of a series of ammonium perchlorate-based composite propellants was determined. Surface-heat fluxes in the range of 2-50 cal/(sq cm) (sec) were employed at pressures of 2-10 atmospheres of nitrogen or helium. Close agreement was found between ignition data derived from these tests when a gas temperature of 750C was used and previously reported data from the thermal radiation heating of the same propellants. When convective heating-gas temperatures above 1000C were used, it was found that the ignition times were about 80 per cent of the values observed at the same mean-heat flux for radiative heating and for tests at lower gas temperatures. In all cases, it was possible to represent the ignition data in terms of a thermal ignition model which considers a single, exothermic, Arrhenius type surface reaction. The indicated activation energy for this reaction is 25-30 kcal/gm mole under all conditions; however, the pre- exponential factor is higher by a factor of five when the higher temperature convective heating gases were employed than under other conditions. It is postulated that reactions in the thin high-temperature boundary layer yield additional energy or reactive species which feed energy back to the surface. Since the activation energy is unchanged, it is presumed that the decomposition reaction of the ammonium perchlorate limits the initial reactive species.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1968
- Accession Number
- AD0841518
Entities
People
- Alva D. Baer
- Charles P. Richardson
- Norman W. Ryan
Organizations
- University of Utah