Numerical simulation of two-dimensional detonation propagation in partially pre-vaporized n-heptane sprays

TL;DR

This study uses numerical simulations to analyze how droplet preevaporation influences two-dimensional detonation propagation in n-heptane sprays, revealing effects on speed, structure, and stability.

Contribution

It introduces a numerical approach to investigate the impact of preevaporated gas equivalence ratio on detonation behavior in two-phase n-heptane-air mixtures.

Findings

Detonation speed and structure are significantly affected by preevaporated gas equivalence ratio.

Cellular detonation structures become more unstable with decreasing preevaporated gas equivalence ratio.

Detonation can propagate without preevaporation but may be quenched and re-ignited at low preevaporated gas equivalence ratios.

Abstract

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.