The Effects of Gaseous Atmospheres on the Performance Characteristics of Aluminum-Sodium Nitrate Flares
Abstract
The burning rates and the light outputs produced by burning binary mixtures of aluminum and sodium nitrate have been studied as a function of composition and of atmospheric content. Also studied were the effects of loading pressure upon the combustion process. The gaseous atmospheres investigated were mixtures of oxygen and nitrogen, argon, or helium. For all systems except those in which the composition was pressed at high loading pressure, the burning rate was unaffected as oxygen concentration was changed, indicating that heat and radiation feedback from the flame have only a minor influence on the burning rate. Consequently, it is hypothesized that the burning rate is essentially controlled by the exothermic processes occurring at or very near to the burning surface. For all systems, the burning composition produced low light output when oxygen was excluded from the atmosphere. With increasing oxygen content, the light output increased by a large factor. This indicates that at low oxygen concentrations much of the metal escaped from the flame unburned. For compositions with low metal content, propagation is very difficult. It is believed that the decomposition of excess sodium nitrate removes heat from the burning surface. This heat loss reduces the rate of vaporization of the metal, causing this vaporization to become the rate controlling step. At the point at which the vaporization rate becomes considerably lower than the rate of oxidation of the metal, the flame will be quenched due to lack of fuel.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1981
- Accession Number
- ADA104383
Entities
People
- Anthony J. Beardell
- Francis R. Taylor
- Patricia L. Farnell
Organizations
- United States Army Armament Research, Development and Engineering Center