A Preferential Model for Electronic Energy Transfer and its Chemistry Coupling in Hypersonic Flows

This work proposes a preferential model of species electronic energy transfer interacting with other energy modes in hypersonic flows. The model has been grounded on the foundation of higher fidelity state-to-state (StS) simulations as the reference data. Zero-dimensional isothermal chemical reactor calculations are carried out using a StS model, which considers the state-to-state collisional transitions among the species electronic states. It is then followed by the model reduction to compress the information obtained from the StS calculations into a modified two-temperature (2T) model formulation by updating existing chemical-kinetic parameters and adding physical terms that have been missed. As a verification, one-dimensional post-normal shock flows in a pure nitrogen mixture are then simulated. With the proposed preferential model, the degree of ionization along the shock layer is predicted with improved accuracy, while further improvement can be achieved regarding the prediction of molecular dissociation.