Combustion of condensed mixtures with polydisperse components

Summary

• 1. A study has been made of the combustion of model mixtures of polystyrene, plexiglas and bitumen with coarse, fine, and mixed (half coarse, half fine) ammonium perchlorate.

• 2. The burning rate of compositions with mixed oxidizer is not generally equal to (u_c+u _f )/2. Depending on the nature of the fuel and the fuel-oxidizer ratio and also on the pressure, u_m may approach u _f (and even exceed it) or u_c (and even fall below it).

• 3. The burning rate of compositions with mixed oxidizer is similar to that of a homogeneous mixture of the fuel and the fine oxidizer filling the gaps between the coarse oxidizer crystals. The presence of coarse oxidizer only slightly reduces or increases the burning rate. However, if this homogeneous mixture is itself incapable of burning or burns very slowly, the presence of coarse oxidizer is important (in this case u_m≤u_c).