Flame evolution in shock-accelerated flow under different reactive gas mixture gradients

Abstract

The interaction between a planar shock wave and a spherical flame is studied numerically for an ethyleneoxygen-nitrogen gas mixture. Influences of different initial reactive gas mixture gradients on the shock-flame interaction are investigated by using high-resolution computational simulations. The results show that the different reactive gas mixture gradients can greatly affect the flame evolution in shock accelerated flow. A detonation only emerges in the homogenous reactive gas mixture case, but a distinct shock bifurcation can be found in the inhomogeneous cases where the leftward reflected shock wave propagates in a reverse flow with a high transverse velocity gradient in the inhomogeneous cases. Also, the flame volume and heat release rate increase when the distribution of the reactive gas mixture is uniform or with a positive gradient in this paper, but decrease when the distribution of the reactive gas mixture is with a negative gradient, however, the ratio of unburned to burned regions in the flame zone shows just the opposite trends. Furthermore, the factors affecting the vorticity generation are also analyzed. It is found that the compression term has a relatively stronger influence on the vorticity generation in all the three cases except the period before the reflected shock wave impinges on the distorted flame in the homogeneous case, wherein the baroclinic effect dominates the vorticity generation in the flame zone.

Essentially non-oscillatory and weighted essentially non-oscillatory schemes

“…A mesoscale study of explosively dispersed granular material was performed in Mo, Lien, Zhang and Cronin (2019). Flame evolution in shock-accelerated flow under different reactive gas mixture gradients was simulated in Zhu et al (2019a). Interaction of two-dimensional free-stream disturbances with an oblique shock wave was studied in Huang and Wang (2019).…”

Near-field relaxation subsequent to the onset of oblique detonations with a two-step kinetic model

“…The ODW initiation is characterized by a transition from oblique shock to detonation on the surface, either smoothly or abruptly, and leads to complicated wave configurations beneath the surface transition region 5,21 . The combustion in supersonic flow may involve the interaction of compression waves, contact surface and reactive front [22][23][24][25] . In early works, the wave configuration was usually described by a steady multi-wave structure issued from a triple initiation point 3,26 .…”