Evaluation of Plateau Burning Behavior in HTPB-AP-Al Composite Propellants

Abstract

The design of solid rocket motors is considered relatively dominated technology in the various areas of knowledge. Even so, there are variables that still need to be better explored. Therefore, the topic presented in this work is related to problems found in designs of HTPB-AP-AL based solid rocket motors that are related to the formation of Plateau in the performance curves (pressure and thrust). This phenomenon has been studied by many researchers, in the way that studies mention different causes. Among the main causes studied, research reports that this phenomenon is related to Ammonium Perchlorate and its granulometric distribution and size, the thermal decomposition kinetics of Ammonium Perchlorate, the distribution and morphology of aluminum and also to the curing agents used in the propellant formulations. The main objective of this work is to present a model built with propellant formulations, considering these variables above mentioned in order to address a good practice to avoid this phenomenon. This work presents burning rates as a function of pressure of several propellant formulations based on ammonium perchlorate (AP) and hydroxyl-terminated polybutadiene cured by isophorone diisocyanate (IPDI) and aluminum (Al), in order to evaluate values of the pressure exponent of the burning rate in distinct pressure ranges, termed as plateau burning rate trends.