Interaction between rotating detonation wave propagation and reactant mixing

Abstract

Rotating detonation engines (RDEs) are widely studied because of their compact configurations and high thermal cycle efficiency. In previous literatures, many investigations on the mixing process in an RDE and the rotating detonation wave (RDW) propagation under non-premixed conditions have been published. However, the two issues were investigated separately, and the interaction between the RDW propagation and reactant mixing has not been studied yet. In this paper, a series of three-dimensional numerical simulations of the mixing process and the RDW propagation in an RDE are performed. The transient explicit density-based solver in ANSYS Fluent is used to perform the simulations. In the cold mixing flowfield, as the back pressure at the chamber exit increases, the axial velocity decreases, and the average resident time of reactant in the chamber increases. Thus the fuel has more time to mix with air in the chamber to provide a better mixing quality. The RDW velocity is very stable during the operation time, whose average value is about 1895 m/s. The velocity deficit is very small. After RDW initiation, the pressure in the combustion chamber increases due to the detonation process. The increased pressure slows down the flowing of the reactant, thus the average resident time of reactant within the height of the RDW increases, making the mixing quality better. The enhanced mixing quality of reactant in turn makes the RDW stronger. Thus, there is a positive feedback between RDW propagation and the reactant mixing.