On regionalization of thermochemical nonequilibrium in scramjet

Thermochemical nonequilibrium significantly affects flow and combustion characteristics in the scramjet of air-breathing hypersonic vehicle. However, a clear map of thermochemical nonequilibrium in scramjets has not been reported. This work simulates thermochemical nonequilibrium combustion flows in Deutsches Zentrum für Luft-und Raumfahrt and HyShot II scramjets, respectively, and shows the comprehensive vibrational and chemical nonequilibrium regionalizations in both scramjets based on defined Damköhler numbers. Vibrational nonequilibrium is mainly located at the edge of the flame, while chemical nonequilibrium is mostly found inside the flame. As the observational length scale extends, the nonequilibrium zone remarkably spreads in the scramjet, which should be paid attention to in future research.