Flame propagation velocity in an air suspension of aluminum particles

The boundaries of stable combustion in a flow of an air suspension of aluminum particles in a wide range of changes in an excess air coefficient (0.1–2.0) are experimentally determined. A characteristic feature of the dependence of a flame blowoff velocity on the excess air coefficient is revealed: the dependence has two maxima. Taking into account the principle of the flame stabilization mechanism, based on the equality of the flow velocity at which the flame is blown off to the flame front propagation velocity, it is concluded that there are two maxima in the dependence of the front velocity on the excess air coefficient, which correspond to the maximum values of heat release and combustion temperature of the air suspension of aluminum particles with an air excess coefficient of 0.2 and 1.0. Previously, these maxima were obtained by other researchers in thermodynamic calculations.