Combustion problems of nitramine propellants udud

摘要

This report summarizes a theoretical investigationudof the current problems of nitramine (composite)udpropellant combustion. This study has, asudits distinctive feature, a detailed examination of theudcondensed-phase processes in the combustion ofudnitramine propellants. As a consequence of a recentlyuddeveloped model for the combustion of ammoniumudperchlorate (AP)/ composite propellants,udit is hypothesized that the condensed-phase degradationudof the nitramine oxidizer particles to a vaporizableudstate is the overall rate-limiting step.udIt is also assumed that the gas-phase details areudsecondary in importance and need be studied onlyudto the extent of supplying the correct boundaryudconditions on the condensed-phase/vapor-phaseudheat transfer. Because of our imprecise understandingudof the gas-phase processes in the presenceudof combustion, several plausible models areudconsidered for the gas phase. It is found that alludof the gas -phas e models considered lead to predictionsudsufficiently clos e to experimental trends forudus to conclude that the precise details of gas -phaseudprocesses are not of critical importance in determiningudpropellant combustion behavior. More toudthe point, we are led to believe that a thorough examinationudof the condensed-phase details may beudsufficient in itself not only to interpret most of theudavailable data on experimental regression rate vs.udpressure of nitramine propellants but also to aidudin the formulation of propellants to suit our needs.