Theoretical studies of real-fluid oxidation of hydrogen under supercritical conditions by using the virial equation of state

Abstract

The Virial equation of state (EoS) was employed to describe the real-fluid impact on H2 oxidation simulation. Different from conventional empirical EoS methods fitted by using critical pressures and temperatures, such as Redlich-Kwong (RK) EoS, the Virial method was constructed with including intermolecular interactions, potentials, and molecular polarizations coupled with real-fluid partition function theory in this work. The Virial method was for the first time incorporated into Cantera software to realize real-fluid simulations with deeper-level physical insights. A series adiabatic/isothermal flow reactor and ignition delay simulations in H2O, N2, and CO2 diluents were performed. The calculations of species compressibility factors and thermodynamic properties by using the Virial method showed a better agreement with experimental data in literature than using the RK method. The Virial method also possessed a better performance in predicting experimental H2 ignition delay times and H2 speciation profiles from literatures. The effects of real fluid through corrections of compressibility factors, thermodynamic properties, and chemical potentials on supercritical H2 oxidation simulations in H2O diluents have been rigorously analyzed, respectively. Moreover, the Virial method performed well at adiabatic conditions in the bath gas of polar molecules like H2O, due to its consideration of molecular polarizations and higher accuracy of thermodynamic property calculations. We believed the Virial method could not only provide accurate estimations of real-fluid behavior, but also provided physical insights in the intermolecular interactions under supercritical conditions.