Determining the boundaries of ignition of aluminum particle aerosuspension in a high-velocity airflow

The results of determining the boundaries of ignition of a turbulent flow of aluminum-air mixture as well as the influence of parameters such as the flow rate, turbulence and particle size on the boundaries of ignition are presented in the paper. It has been found that as the initial turbulence increases the nucleation site for ignition splits under the influence of pulsation and flame tails are carried into the main stream and die out there, thus increasing the time of ignition of the main flow of the mixture; as the initial  turbulence increases the boundaries of aluminum-air mixture ignition expand and the flow rate of the aluminum-air mixture increases; the boundary of ignition of a powdered aluminum-magnesium alloy corresponds to the boundary of ignition for combustion chambers of aircraft gas turbine engines; presence of fine aluminum powder particles in the area of ignition contributes greatly to the expansion of the boundaries of  ignition of the flow of aluminum-air mixture. It has also been established that the maximum velocity of flame propagation and heat generation for aluminum-air mixture is observed when the mixture composition is close to stoichiometric, just as for gas-air mixtures. However, a distinguishing feature of aluminum-air mixture is the presence of the second maximum speed of flame propagation and heat generation for mixture compositions with α<0.3. The resulting boundaries of ignition of aluminum-air mixture lie within the area of flame stabilization.