Kinetic modeling and sensitivity analysis for B/H/O/C/F combination systems

Abstract

A kinetic model is presented to describe the high-temperature, gas-phase B/H/O/C/F chemistry associated with fluoroamino/nitroamino/B(s) mixtures. The results of thermodynamic constant temperature and pressure calculations for a prototypical fluoroamino/nitroamino-based oxidizer and solid boron are presented to characterize the equilibrium speciation. Key gas-phase reactants are selected and a reaction mechanism describing potential reaction pathways is formulated. Rate parameters for elementary reactions were obtained from published experimental/theoretical data or estimated using transition state argments and scaling relations. The results of kinetic calculations for several adiabatic systems are presented which illustrate the general high temperature mechanistic behavior of B/H/O/C/F systems. Standard reaction flux/pathway and gradient sensitivity analysis techniques are used to identify important reaction pathways. The model results consistently show that OBF(g) is the major high-temperature combustion product. Thermodynamic and kinetic calculations further indicate that for oxygen/fluorine mole ratios near unity, the postcombustion gases will not contain liquid B 2O 3. The model results indicate that relative to B/H/O/C systems, the gas phase kinetics are as fast or faster with fluorine enrichment and that the heat release rate is increased. However, the modeling results also indicate that this feature is sensitive to the oxygen/fluorine mole ratio.