Numerical Investication of Chemical Kinetics Effects In Nozzles for Winged Launchers

The nozzle performances in many air breathing propulsive devices proposed for high speed flight are strongly influenced by the nonequilibrium phenomena. In particular the two-dimensional gasdynamic effects have an important role, since they may significantly affect the evolution of the reaction mechanism, and thus determin the prediction of the chemical energy released to the flow and available for thrust. In this paper axisymmetric plug nozzles are analyzed by means of a nonequilibrium flow model. They display strong unsymmetrical flow behaviours, which yield very peculiar consequences on the evolution of chemical kinetics. Significant displacements are reported between the prediction of the propulsive parameters obtained by using a non-reacting flow model with respect to the chemical nonequilibrium model.