Combustion Time in Aluminum Dust Clouds

An experimental investigation has been conducted to determine combustion time of 18 microns aluminum particles-laden aerosols using fluidized bed apparatus. The aerosol compositions consisted of 18-micron aluminums particle with (25%O2 & 75% N2) in various dust concentration. The dust concentration، c، was varied from 95 to 650 g/m3 (0. 3<φ<2. 1). Measured combustion times of Al particles / gas mixture were found to be independent of dust concentration in fuel rich zone (1<φ) with a small decreasing. Increasing of dust concentration in lean zone causes decreasing combustion time. Combustion time decreases in comparison of combustion with air. Combustion time was found with t = δ/Sb equation. Where δ: flame thickness and Sb: burning velocity. Flame thickness was found from quenching distance and burning velocity was found from flame velocity.