Characterizing thermodynamic properties of pure components and binary mixtures at rocket conditions using molecular dynamics

T. Weathers, A. Hosangadi, A. Vishnyakov, Y. Chiew

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations


Conventional descriptions of mixing and combustion processes are inadequate for conditions seen in rocket engines. Mixtures at these conditions can exhibit complicated nonlinear critical locus behavior that is strongly dependent on composition, temperature, and pressure. As a step towards better understanding the mixing process, thermodynamic properties for pure component and binary mixture systems have been computed using molecular modeling techniques at both subcritical and supercritical conditions. Molecular models were first validated by analyzing pure component systems and comparing against available experimental data. After the capabilities and limitations of the models were understood, simulations were performed to compute and predict properties of binary systems. Properties of interest include density, heat capacity, enthalpy of vaporization, and vapor-liquid equilibrium. The pure components analyzed are those found in rocket engines including nitrogen, carbon dioxide, water, and dodecane. The binary systems analyzed include alkane-nitrogen, alkane-carbon dioxide, and alkane-water. The single component simulations showed that simple models available for N2, CO2, and H2O reliably reproduce experimental densities of coexisting vapor and liquid, saturation pressures, and heats of evaporation. For dodecane the simple united atom models give good agreement with experimental data for the VLE data but not for predicting heat capacity. The binary mixtures simulations showed that the simple models using the Lorentz-Berthelot mixing rule (kij =1) are not able to accurately predict the VLE data. Adjusting the kij value to 0.935, 0.95, and 1.3 proved to increase prediction accuracy for alkane-nitrogen, alkane-carbon dioxide, and alkane-water respectively.

Original languageEnglish (US)
Title of host publicationAIAA Scitech 2019 Forum
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624105784
StatePublished - Jan 1 2019
EventAIAA Scitech Forum, 2019 - San Diego, United States
Duration: Jan 7 2019Jan 11 2019

Publication series

NameAIAA Scitech 2019 Forum


ConferenceAIAA Scitech Forum, 2019
Country/TerritoryUnited States
CitySan Diego

All Science Journal Classification (ASJC) codes

  • Aerospace Engineering


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