Combustion process during metallic dust flame propagation is still a point of discussion. Heterogeneous combustion (between solid particles and the air) or partial heterogeneous combustion followed by homogeneous combustion (in the gas phase) are two possible metallic combustion processes.
In this work, aluminium flame propagation inside a tube is studied. Some experimental observations of this flame propagation mechanism are presented: as for example, micro-explosions of particles, white tail-like light following particles... These different observations seem to agree with a (partial) homogeneous combustion process in the gas phase.