CYCLOPS, A Breakthrough Code to Predict Solid-Propellant Burning Rates

摘要

Theoretical capability to predict the burning rate of real propellants from their ingredients would be an invaluable aid to formulating new propellants. Despite progress over the last decade on a very few simple ingredients, such as cyclotrimethylenetrintramine (RDX), and a few simple binary mixtures, no general capability of this sort exists today. This shortcoming is not due to insufficient computational resources, but to a lack of understanding of fundamental combustion mechanisms in the condensed phase and surface gas interlace for typical propellant ingredients and their mixtures. This difficult problem is likely to remain intractable for some time to come. In this report, we demonstrate that our previously published semi-empirical formalism for single ingredients can be success fully extended to treat multi-ingredient propellants. In particular, for purposes of this report, we confine ourselves to nitrate- ester propellants, using MlO, M2, M9, and JA2 as examples. However, the method should also be applicable to other classes of homogeneous propellants and even composite propellants where mixing of ingredients in a surface melt layer or sufficiently small particle sizes remove the multi- dimensional character. The method treats the gas-phase processes on the level of elementary reaction and multicomponent transport. A semi-empirical pyrolysis law coupled with informed estimates of the decomposition products of the condensed phase enables us to finesse the absence of knowledge of the detailed processes occurring in the condensed phase and at the burning surface. Results of a computer code, CYCLOPS, based on this approach, show that both the burning rate and flame structure are well predicted for a series of four U. S. Army gun propellants.