The effects of NO2 on the combustion process of double base propellants

Abstract

In studying, the combustion of Double Base (DB) propellants, a coulometric nitrogen oxides detector, differential scanning calorimetry (DSC) and a long-focus microphotographic camera were used to determine, respectively, the amounts of NO2, NO, the dissociation heatand the activation energy Ē and the dark zone thickness L. The results are as follows: NO2/NO F2mg/F0.4mg mcal/mg Ēkcal/mol L Prop. A 7.1% 0.63 478 35 decreases slightly Prop. O 11.6% 0.73 448 40 Prop. B 14.0% 0.80 318 57 decreases greatly where Propellant A=catalyzed high burning rate propellant Propellant O=noncatalyzed propellant for contrast Propellant B=catalyzed plateau propellant and F represents the peak area per 1 mg propellant It can be seen from the analysis of the above results that in the combustion process of the double base propellant there must be a heterogeneous gas-solid reaction between NO2 and the propellant, and that this reaction is an important step that affects the combustion rate of the propellant. Rate increasing catalysts will catalyze this reaction, and as a result, the burning rate can be increased greatly. Inhibition of such a reaction by plateau catalysts is one of the factors that produce the plateau. Both sets of catalysts are effective in the dark zone, but they have no significant effect on the burning rate.