The primary zone in the combustion of solid propellants containing catalysts

Using a scanning electron microscope and an x-ray microprobe analyzer, we investigated the structure and composition of the combustion surface of the N propellant containing catalysts (PbO$_2$, CuO, PbO$_2$+CuO) which was extinguished at various pressures. Based on the obtained results, the heat-transfer coefficient was calculated for the layer above the catalyzed propellant combustion surface and found to be greater than that of the gas by factors ranging from 1.5 to 15. The calculation of the C-phase heat balance for the N propellant with additives showed that the rise in the combustion rate is caused by the increased quantity of heat entering into the C-phase from the zone above the combustion surface. Thus, the driving stage in the combustion of catalyzed propellants is the zone above the combustion surface and not the C-phase reaction layer, as in the case of the propellants without any catalysts.