Dissociation-Recombination Models in Hypersonic Boundary Layer O2/O Flows

A recent complete set of oxygen atom-molecule collision rate coefficients, calculated by means of a quasiclassical trajectory (QCT) method, has been used to evaluate the vibrational non-equilibrium in hypersonic boundary layer flows. The importance of multiquanta transitions has been demonstrated. Moreover a new 'direct dissociation-recombination' (DDR) model has been adopted and the corresponding results differ from the ones obtained with the Ladder-Climbing (LC) model, characterized by the extrapolation of bound-to-bound transitions to the continuum. The heat flux through the boundary layer and at the surface have been calculated too.