  In this paper, two dimensional detonation propagation in partially
prevaporized n-heptane sprays is studied by using Eulerian/Lagrangian methods.
The effects of droplet preevaporation on the detonation propagation are
investigated. The general features and detailed structures of two-phase
detonations are well captured with the present numerical methods. The results
show that the detonation propagation speed and detonation structures are
significantly affected by the preevaporated gas equivalence ratio. The
numerical soot foils are used to characterize the influence of preevaporated
gas equivalence ratio on the detonation propagation. Regular detonation
cellular structures are observed for large preevaporated gas equivalence
ratios, but when decreasing the preevaporated gas equivalence ratio, the
detonation cellular structures become much more unstable and the average cell
width also increases. It is also found that the preevaporated gas equivalence
ratio has little effects on the volume averaged heat release when the
detonation propagates stably. Moreover, the results also suggest that the
detonation can propagate in the two-phase heptane and air mixture without
preevaporation, but the detonation would be first quenched and then re-ignited
when the preevaporated gas equivalence ratio is small or equal to zero.
