Detailed Combustion Modeling as an Aid to Propellant Formulation: Two New Strategies

摘要

There has been considerable progress recently in the development and use of elementary chemical reaction mechanisms to describe the gas phase energy release of energetic materials. Such advances present an opportunity to examine the extent to which these models might be used to provide guidance to the propellant formulator. In this report, we develop two methodologies that may prove helpful to the development of propellant formulations with tailored combustion characteristics. First, the dependence of the burning rate on the path of condensed phase decomposition was computed for nitroglycerine (NG) combustion. It was found that some sets of decomposition products lead to nearly an order of magnitude higher burning rate than is observed experimentally. This indicates that efforts to influence the path of decomposition might be a novel and powerful approach to tailoring burning rate. Second, a methodology for calculating the effectiveness of different chemical additives on the burning rate was developed and demonstrated for several chemical additives added to NG. Burning rates were calculated for the additives H2, CH2O, and NH3 and flame structure calculations made for HNCO as an additive. NH3 accelerates the burning rate of NO, and HNCO is expected to retard it; both reduce the dark zone length and thus may reduce ignition delays in guns.