Parametric Investigation on the Sensitivity of the Simplified Aluminum Combustion Modeling

Abstract

As a preliminary evaluation of system applicability, parametric studies were conducted to figure out primary parameters and their effects with a previously developed simple mechanistic model of single aluminum particle combustion. Initial particle size, ignition temperature, initial oxide film thickness, convection, radiation, heterogeneous surface reaction (HSR), ambient pressure and temperature were selected as the primary parameters. It was intended to deduce a proper ignition temperature from ignition delay time by comparing the predictions with the calculated results of Friedman’s equation. However, the equation of ignition delay was also restrictive in its employment, and thus a melting temperature of aluminum oxide was selected for the ignition temperature as it was before. Ignition delay and burning time were proportional to the particle size increment and flame temperature of small particle was higher than that of bigger one. Influence of initial film thickness on the particle ignition and burning characteristics was insignificant. Ignition delay drastically decreased with the HSR and the radiative heat transfer was as important as the convective heat transfer in quasi-steady combustion (QSC) process. The higher the ambient pressure, the shorter the particle burning time, and burning rate (slope of the D 2 curve) was proportional to P 0.095 . Temperature of both particle and flame increased at higher ambient pressure and flame radius was opposite. Burning time decreased as the ambient gas temperature increased, and burning rate was proportional to T 0.116 .