Dynamic detonation stabilization in supersonic expanding channels

Abstract

realized through the dynamic control of a moving boundary.

Mechanism of detonation stabilization in a supersonic model combustor

“…It is found that, for this given expansion angle, detonation sustainment can be maintained in supersonic flows in the same position after the shutdown of the hot jet (Cai et al . 2019).…”

“…It is found that detonation sustainment can be maintained almost in the same position after the shutdown of the hot jet, suggesting that quasi-steady propagation of detonation can be achieved in this case for a given expansion angle; however, it should be noted that normally the quasi-steady state of detonation propagation can only be maintained for a limited time because the detonation may gradually attenuate and finally fail due to the Prandtl–Meyer expansion fan resulting from the expanding wall (Cai et al . 2019). Overall, for the two approaches, the cavity can lead to the formation of an overdriven detonation due to enhancement of pressure oscillations while the quasi-steady state of detonation propagation can be maintained for only a limited time because of the expanding wall.…”

“…In the present work, the reactive compressible Navier-Stokes (NS) equations are solved to identify the mechanism of detonation stabilization in a supersonic model combustor (Sun et al 2008;Potturi & Edwards 2015), which consists of an expanding wall and a cavity. Previous investigations (Cai et al 2018a(Cai et al , 2019 have shown that both the cavity and expanding wall configurations can result in the generation of unburned jets, whose consumption and subsequent heat release are subjected to rapid turbulent mixing and diffusion. It is reported that the inviscid paradox can be solved with the inclusion of the diffusive effect (Radulescu 2018) and the absence of small-scale turbulent interactions, normally not properly accounted for in detonation modelling using Euler simulations, leads to significantly lower burning rates than observed experimentally and hence does not permit detonation self-sustainment (Radulescu et al 2005).…”

Effects of velocity shear layer on detonation propagation in a supersonic expanding combustor

“…Wang et al 18 reported that the interaction between the oblique detonation wave and expansion fan induces a new wave structure in the expanding channel. Cai et al 12,19 conducted a numerical simulation of detonation in an expanding channel. They 12,19 demonstrated that the heat release from the combustion of the unburned jet behind the detonation front, promotes dynamic and stable propagation of the detonation wave.…”

“…Cai et al 12,19 conducted a numerical simulation of detonation in an expanding channel. They 12,19 demonstrated that the heat release from the combustion of the unburned jet behind the detonation front, promotes dynamic and stable propagation of the detonation wave. The rapid jet consumption resulted in appearance of fluctuations and pressure oscillations in the flow field, eventually attenuating the detonation wave.…”