Effects of total temperature and equivalence ratio on n-decane/air two-phase rotating detonation wave

The Eulerian–Lagrangian method is used to conduct the numerical simulation of the non-premixed two-phase rotating detonation wave (RDW) fueled by n-decane/air. The stratified spray detonation transient phenomena, as well as the effects of total temperature (850, 900, 1000 K) and equivalence ratio (0.5, 0.7, 1.0) on the RDW dynamics and propagation characteristics are discussed in detail. The results indicate that the velocity difference caused by separate injection of fuel and air generates the low-temperature zone behind the oblique shock wave, which hinders the direct contact between the droplets and the detonation products. Droplets in the refilled zone are broken by the shear effect and evaporate in high total temperature air, forming the stratified distribution structure of droplets and vapor. In addition, the coupling–decoupling–recoupling dynamic mechanism is observed between the leading shock front and the heat release zone, which leads to the local decoupling of RDW during the propagation. Moreover, the spatial variation of high-pressure zones at the leading shock front leads to multiple leading shock fronts and transverse pressure waves. It is revealed that the increase in total temperature broadens the lower boundary of equivalence ratio to obtain two-phase RDW. RDW velocity and velocity deficit are insensitive to the total temperature in the considered parameter range. However, the increase in the total equivalence ratio not only improves the mean velocity significantly but also enlarges the velocity deficit. With the increasing total temperature and equivalence ratio, the stability of pressure becomes worse. Furthermore, the stability of velocity declines with the increasing equivalence ratio at the total temperature of 1000 K.