ЗАВИСИМОСТЬ РАЗМЕРА ЗОНЫ ПЛАМЕНИ ОДИНОЧНЫХ ЧАСТИЦ АЛЮМИНИЯ ОТ ДАВЛЕНИЯ

Abstract

Mathematical modeling of geometric dimensions and thermodynamic parameters of flame around single aluminium under combustion in the 79 % Ar + 21 % O2 atmosphere was implemented. The modeling was carried out on the basis of summarizing of experimental data and results of thermodynamic analysis. The dependencies of temperature and oxidizer (oxygen) concentration on the flame boundary and pressure of surrounding medium on particle size were determined. Also relation of flame radius with particle radius was established. The calculations was realized according to model of diffusion mode combustion with taking into account quasistationarity and thermodynamic equilibrium of processes, from the assumption of spherical symmetry of the flame. The flame boundary, oxidizer concentration and temperature on the boundary are determined on the basis of condition of predetermined completeness of aluminium transformation into ultrafine oxide Al2O3. The relative size of flame zone is established to decrease from 4.5 to 6.8 when surrounding medium pressure changes from 0.1 to 6 MPa. The relative size of flame zone and oxidizer concentration on the flame boundary increase as the particle burn out. As the particle radius decreases the part of radiative heat exchange decreases in total balance of it’s energy. And the part of radiative heat exchange does not exceed 8 % for industrial aluminium powders with particles diameter less than 50 m. The surrounding medium pressure influences on values of parameters calculated essentially with the exception of part of radiation heat flow.