  Utilizing a two-phase supersonic chemically reacting flow solver with the
Eulerian-Lagrangian method implemented in OpenFOAM, this study computationally
investigates the formation of liquid-fueled oblique detonation waves (ODWs)
within a pre-injection oblique detonation wave engine operating at an altitude
of 30 km and a velocity of Mach 9. The inflow undergoes two-stage compression,
followed by uniform mixing with randomly distributed n-heptane droplets before
entering the combustor. The study examines the effects of droplet breakup
models, gas-liquid ratios, and on-wedge strips on the ODW formation. Results
indicate that under the pure-droplet condition, the ODW fails to form within
the combustor, irrespective of the breakup models used. However, increasing the
proportion of n-heptane vapor in the fuel/air mixture facilitates the ODW
formation, because the n-heptane vapor rapidly participates in the gaseous
reactions, producing heat and accelerating the transition from low- to
intermediate-temperature chemistry. Additionally, the presence of on-wedge
strips enhances ODW formation by inducing a bow shock wave within the
combustor, which significantly increases the temperature, directly triggering
intermediate-temperature chemistry and subsequent heat-release reactions,
thereby facilitating the formation of ODW.
