Investigation on propagation characteristics and mode transition of diesel/air two-phase rotating detonation waves

In this work, experiments and numerical simulations are conducted to investigate the behavior of diesel/air two-phase rotating detonation wave. The combustion mode capture, propagation characteristics, and mode transition of two-phase rotating detonation waves were analyzed. The results demonstrate that with increase in the total equivalence ratio, the combustion mode changes from unburned mode to deflagration mode and detonation mode. Single-wave mode of rotating detonation wave is obtained with a propagation velocity of 1036 m/s. Besides, in the process of rotating detonation wave propagation, the formation, collision, and quenching phenomena can be observed. The generation and development of local hot spots are the key factors affecting rotating detonation wave propagation, which are determined by the local pressure gradient and heat release rate. Moreover, the mode transition of rotating detonation wave includes the generation of local hot spot, the collision between two rotating detonation waves, and the collision between rotating detonation wave and shock wave. High droplet evaporation rate and appropriate equivalence ratio are important for achieving self-sustained propagation of rotating detonation waves. The analysis results can provide helpful suggestions for the design of two-phase rotating detonation engines.