Abstract:

Large eddy simulation is conducted to explore the flow field structure and to analyze the features of the supersonic reaction mixed layer formed between the strut rocket jet and the airstream in a RBCC combustor model with the flight Ma=4.5, which is a typical working state in the flight regime of the RBCC vehicle. The results show that the rocket jet interacts with the airstream because of the existence of velocity gradient forming an annular shear layer containing various vortex structures that play important roles in the turbulent mixing and combustion. With the turbulent energy cascade transport, chemical energy released during the reaction is converted into small-scale turbulent kinetic energy. Large-scale vortexes transfer the energy to small-scale ones that dissipate its energy eventually. On one hand, small-scale vortexes can promote mixing and enhance the combustion process. On the other hand, they can bring pulsation to the chemical reaction, making the local flame quenching and the flame structure unsteady.

Key words: RBCC combustor, Strut rocket, Supersonic reacting shear layer, Large eddy simulation