Speaker
Description
This work presents the STELLAR (State-To-State ELementARy Rates) database update for CO$_2$, providing a dataset suited for the modeling of vibrationally-specific excitation (V--T) and dissociation (V--D) processes in Carbon Dioxide.
The implemented datasets provide a better and more physically consistent description of the physical-chemical processes in emerging applications (such as state-to-state modeling of Venus and Mars atmospheric entries, plasma reforming of SynGas, or oxygen production on Mars), as compared to legacy approaches such as the ones based on fist-order perturbation theories (FOPT), such as the SSH model.
The dataset proposed here is based on the Forced Harmonic Oscillator (FHO) theory, which is known to be capable of providing more physically-consistent rates in the high translational temperatures regime of shocked flows, as compared to FOPT theories. The FHO theory has been extended to the modeling of collisions between linear triatomic molecules such as CO2, and phenomenological intermolecular potentials have been selected through comparisons with experimentally obtained state-to-state rates.
Although the proposed theoretical description is a considerable improvement from legacy FOPT descriptions, it still makes use of a considerable deal of underlying assumptions and is expected to be superseded in the future by more sophisticated approaches such as Potential Energy surfaces (PES) based trajectory models. However it is expected that this dataset will help improve the accuracy of the state-to-state models developed in atmospheric entry applications and most critically Mars and Venus entry applications, since CO2 radiation is a considerable design driver, who strongly depends on an accurate description of the V--T and V--D rates of excitation and dissociation of CO2.
An application of the model to two theoretical test-cases such as the relaxation from initial conditions (Ttr,Tv) = [10,000K, 300K] (heating of the gas to 10,000K), and relaxation from initial conditions (Ttr,Tv) = [300K, 10,000K] (cooling of the gas to 300K) is also presented in this work.
Summary
A new state-to-state model for CO2 dissociation
