Dynamic detonation stabilization in supersonic expanding channels

Abstract

In the present work, dynamic detonation stabilization in expanding channels is numerically investigated by injecting a hot jet into a hydrogen–oxygen combustible mixture flowing at supersonic speed. The two-dimensional reactive Navier–Stokes equations and one-step two-species reaction model are solved using a hybrid sixth-order WENO-Centered Difference (CD) scheme based on the SAMR (Structured Adaptive Mesh Refinement) framework. The results show that the highly unstable shear layer interactions with the unburned jet resulting from the Prandtl-Meyer expansion fan result in numerous large-scale vortices, which contribute significantly to rapid turbulent mixing and diffusion effects. This can further facilitate the consumption of the unburned jet and its subsequent heat release to support the dynamically stationary propagation of detonation. Meanwhile, detonation attenuation in the supersonic flow can be also effectively suppressed because of the formation of a hydrodynamic channel associated with a corresponding hydrodynamic throat. It is indicated that the shear layer interactions with the unburned jet and the generation of hydrodynamic channel can both play important roles in dynamically stationary propagation of detonation in supersonic expanding channels after the shutdown of the hot jet. With the increase of the expansion angle, the enlarged unburned jet is gradually extended out of the sonic line, and the deficit of heat release cannot contribute to stationary propagation of detonation, thus eventually leading to detonation failure. It is indicated that there might exist a critical angle θ_CT. Dynamic stabilization of detonation can be realized in expanding channels when the angle is smaller than θ_CT, while the detonation propagates below the CJ velocity and finally fails when the angle is larger than θ_CT. Through the control of a moving boundary by dynamically changing the expansion angle, the continuous detonation attenuation can be effectively suppressed and finally turned to forward propagation successfully, indicating that dynamically stationary propagation of detonation can be realized through the dynamic control of a moving boundary.

More information

Identifiers

ORCID for Ralf Deiterding: orcid.org/0000-0003-4776-8183

Catalogue record

Export record

Altmetrics