Numerical Simulations of Liquid-Fueled Rotating Detonation Engines Using the KHRT Droplet Breakup Model

We present results from the numerical investigation of a three-dimensional unrolled Rotating Detonation Engine (RDE) with detailed particle modeling using the Eulerian-Lagrangian method. The simulations were performed with n-dodecane injected in both liquid and vapor phases and pure oxygen as reactants. Mono-disperse injection is considered with three different injection diameters of 5, 15 and 30 µm. Droplet breakup was modeled based on the stability of Kelvin-Helmholtz and Rayleigh-Taylor instability (KHRT) modes that form on the droplet surface. We find that most droplets in the refill region of the RDE did not undergo KH breakup, as they interacted with the detonation wave before the predicted breakup time is reached. On the other hand, RT unstable modes were found to be stabilized by surface tension forces. However, following interaction with the detonation wave, rapid breakup and evaporation is observed at the detonation front. We show that due to the particle lag in the refill region, the upper section of the detonation wave is devoid of liquid fuel. This fuel-oxidizer segregation increases with diameter as the larger diameter droplets experience higher lag. We also find that the detonative burning is higher for smaller droplets as they evaporate and burn rapidly.