Analysis of combustion peculiarities in flame zone of aluminium particle

Metallic particles being added to rocket fuel contribute to increasing its energetic efficiency. In the present paper, the physical model of aluminum particle combustion is developed. The model takes into account accumulation and distribution of condensed oxide in the flame, which is divided into characteristic zones at that. The thermodynamic analysis of flame parameters for a single particle burning in medium "79% Ar + 21% O-2" was carried out. The mathematical description of the model is presented, which lets to calculate dependencies of temperature and oxidizing components concentration on relative flame radius (R) over bar which is ratio of inner flame points coordinate R to current particle radius R-0. The calculation method is based on combined use of heat and oxidizer flows balance and on data of equilibrium thermodynamic analysis of flame zone. The calculation of the mentioned dependencies were carried out for aluminium particles 220 mu m (220 mu m) in diameter at ambient environment pressure equal 0,1 MPa. The following radii were determined: radius of stoichiometry of metal and oxygen flows, radius of maximum temperature value reach and that of flame boundary. New parameter ri is introduced which determines degree of metal transformation into condensed oxide and depends on thermodynamics parameters of flames (on temperature and oxidizing components concentration). The maximum of oxide particles distribution is established to be in zone of 5,5 <= R/R-0 < 6,6, at that eta value reaches 90%. The results of present work are compared with data of theoretical and experimental investigations of other authors. The accountability of equilibrium thermodynamics is shown to be mandatory part of models of aluminum particles combustion.