Ignition and Combustion of Aluminum Hydride Dust Aerosols

Abstract

ABSTRACT The results of comparative experimental studies of aluminum hydride AlH3 and aluminum Al particle aerosols, in particular, of the critical conditions for auto-ignition and the features of the flame propagation in low-volume (V ≈ 5.1·10−3 m3) and large clouds (volume is varied from 40 to 60 m3) are presented in this article. Experiments have shown that for aerosols of AlH3 particles, the auto-ignition temperature is much lower than for aluminum particles. This is due to the thermal decomposition of aluminum hydride into hydrogen and active aluminum. The laminar flame was studied in low-volume clouds. A two-frontal form of a laminar flame wave in AlH3 aerosol was found. Moreover, the visible flame propagation speeds for AlH3 correspond to those for finely dispersed Al and are two times higher compared to coarse Al. The turbulent flame in the large free clouds of aluminum hydride dusts has flame propagation speeds several times higher than those in the aluminum clouds and is characterized by the formation of a toroid vortex with a complex internal structure.