Upper concentration limit of combustion of condensed mixtures

Abstract

1. We have determined the position of the upper concentration limit of combustion for mixtures of ammonium perchlorate and polystyrene and polymethyl methacrylate. For the AP+PS mixture the limiting excess of fuel (at which the mixture still burns) is 2\2-3 times greater than for the AP+PMM mixture. In all cases αu is the greater, the higher the pressure and the larger the oxidizer particle size. In these experiments the richest mixture still capable of burning (at p=100 atm and dox=140–320 μ) corresponded to α≃0.055 (about 67% fuel) for polystyrene and to α≃0.12 (∼60% fuel) for polymethyl methacrylate. 2. We have determined the burning rate at the upper limit uu. For the AP+PS mixture uu is almost constant at all p and dox and corresponds to about 1mm/sec. For AP+PMM the value of uu is generally higher than for AP+PS and decreases with increase in p and dox. 3. The results of the experiments can be explained on the basis of the influence (\ldactive combustion\rd) zone concept.