Model Independent First Principles Method for Prediction of Heat of Condensation/Sublimation of Solid Propellant

Designing next generation propellants requires an a priori prediction of their properties. Heat of sublimation is one such property that is required to theoretically estimate specific impulse. The state-of-art approach for estimating heat of sublimation is based on model compounds and empirical correlation, which has large RMS deviation. In Phase I, CFDRC has demonstrated that the first-principle-based statistical thermodynamics method with high potential to accurately predict heat of sublimation and vaporization for any compounds with any chemical functionality. The Phase II effort will build off of Phase I by expanding the scope of the COSMO-RS to calculate heats of phase change for both solid and liquid propellants within the same theoretical framework. A large set of molecules with variety of functionalities will be identified for refinement and re-parameterization of the atomic parameters. The developed model will then be validated against another set of test of compounds. Finally, due to DoD’s interest, the model will be extended to incorporate ionic liquids/solids. Once validated, the developed model will be integrated into a consistent computational environment consisting of a molecular structure builder, quantum chemistry packages, and propellant performance estimation software to enable a non-expert user to reliably estimate propellant properties for novel hypothesized compounds.