AN EXTENSION OF CVDV MODEL TO ZELDOVICH EXCHANGE-REACTIONS FOR HYPERSONIC NONEQUILIBRIUM AIR-FLOWS

A new preferential vibration-dissociation-exchange reactions coupling model - labelled CVDEV - resulting from an extension of the well-known Treanor and Marrone CVDV model, has been derived to take into account the coupling between the vibrational excitation of the N-2 and O-2 mo lecules and the two Zeldovich exchange reactions. Analytical expressio ns for the exchange reactions coupling factor and for the average vibr ational energy lost - or gained - by a molecule through an exchange re action have been developed. The influence of such a coupling has been shown by means of numerical simulations of hypersonic air flows throug h normal and bow shock waves. Code-to-code comparisons between our mod el and other recent approaches have been conducted. The infrared radia tion of nitric oxide behind a normal shock wave resulting from computa tions with the CVDEV model has been compared with other coupling model results and to recent shock tube experimental data. These comparisons have shown a good agreement of our model results with the experimenta l data. In this context, the results show the prominent influence of N -2 vibration coupling on the first Zeldovich reaction, and the absence of O-2 vibration coupling effects on the second Zeldovich reaction.