Numerical Investigation of Two-Phase n-Decane/Air Rotating Detonation Engines With Different Numbers of Fuel Orifices

In this study, n-decane/air two-phase rotating detonation is numerically investigated based on Eulerian-Lagrangian method. Three-dimensional rotating detonation chamber (RDC) with various numbers of fuel orifices (30, 45, 60, and 90) is considered. The effects of numbers of fuel orifices on the fuel-mixing characteristics, the flow field structures, and the propagation characteristics of the rotating detonation wave (RDW) are analyzed. The results show that the liquid fuel mixing is influenced by the fuel jets and the incoming air shear. The former mainly affects the mixing uniformity, while the latter has a great influence on the Sauter mean diameter. Specifically, increasing the numbers of fuel orifices improves the mixing uniformity but slightly rises the Sauter mean diameter. Besides, the number of fuel orifices has a significant impact on the propagation mode of RDW. Single-wave mode is established in RDC except for the 30 orifices. Furthermore, a dimensionless kinematic parameter (alpha) is used to represent the fuel reactivity and predict the propagation mode of RDW. Moreover, the propagation parameters of RDW vary greatly with different numbers of fuel orifices. As the number of orifices increased, the formation time to stable operation of RDW decreases. The research results can provide guidance for the design of two-phase rotating detonation engine (RDE).