Ignition criteria and the effect of boundary layers on wedge-stabilized oblique detonation waves

Bachman, Christian L.; Goodwin, Gabriel B.

doi:10.1016/j.combustflame.2020.10.007

Cited by 32 publications

(8 citation statements)

References 34 publications

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“…This method is discussed in detail in ref. 32. The maximum computational cell size is 1.4 mm, and the minimum is 11 µm.…”

Section: Numerical Simulationsmentioning

confidence: 99%

“…The reactions are modeled with a simplified, calibrated chemical-diffusive model (CDM) that uses a single Arrhenius reaction rate to convert reactants to products. The CDM has been used extensively in detonation studies, shown to reproduce desired combustion properties, such as detonation wave speed and flame temperature (33)(34)(35), and was used recently to study ODW ignition and stability characteristics when a boundary layer is present on the wedge surface (32). For this study, the CDM was optimized for a hydrogen-air mixture.…”

Section: Numerical Simulationsmentioning

confidence: 99%

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Stabilized detonation for hypersonic propulsion

Rosato

Thornton

Sosa

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Future terrestrial and interplanetary travel will require high-speed flight and reentry in planetary atmospheres by way of robust, controllable means. This, in large part, hinges on having reliable propulsion systems for hypersonic and supersonic flight. Given the availability of fuels as propellants, we likely will rely on some form of chemical or nuclear propulsion, which means using various forms of exothermic reactions and therefore combustion waves. Such waves may be deflagrations, which are subsonic reaction waves, or detonations, which are ultrahigh-speed supersonic reaction waves. Detonations are an extremely efficient, highly energetic mode of reaction generally associated with intense blast explosions and supernovas. Detonation-based propulsion systems are now of considerable interest because of their potential use for greater propulsion power compared to deflagration-based systems. An understanding of the ignition, propagation, and stability of detonation waves is critical to harnessing their propulsive potential and depends on our ability to study them in a laboratory setting. Here we present a unique experimental configuration, a hypersonic high-enthalpy reaction facility that produces a detonation that is fixed in space, which is crucial for controlling and harnessing the reaction power. A standing oblique detonation wave, stabilized on a ramp, is created in a hypersonic flow of hydrogen and air. Flow diagnostics, such as high-speed shadowgraph and chemiluminescence imaging, show detonation initiation and stabilization and are corroborated through comparison to simulations. This breakthrough in experimental analysis allows for a possible pathway to develop and integrate ultra-high-speed detonation technology enabling hypersonic propulsion and advanced power systems.

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“…This method is discussed in detail in ref. 32. The maximum computational cell size is 1.4 mm, and the minimum is 11 µm.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Section: Numerical Simulationsmentioning

confidence: 99%

Stabilized detonation for hypersonic propulsion

Rosato

Thornton

Sosa

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

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show abstract

“…The initiation structures and mechanisms of ODWs have been widely investigated with gaseous fuels (Teng, Ng & Jiang 2017; Martínez-Ruiz et al. 2020; Bachman & Goodwin 2021; Teng et al. 2021 b ; Domínguez-González et al.…”

Section: Introductionmentioning

confidence: 99%

“…2022). The effects of boundary layers are investigated and an ignition criterion to predict the formation of an ODW for a given inflow temperature are established (Bachman & Goodwin 2021). However, these studies used a global or detailed reaction model of gaseous fuels without focusing on ODWs in liquid fuels.…”

Section: Introductionmentioning

confidence: 99%

Propagation instabilities of the oblique detonation wave in partially prevaporized n-heptane sprays

Tian,

Teng,

Shi

et al. 2024

J. Fluid Mech.

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Two-dimensional oblique detonation wave (ODW) propagations in partially prevaporized n-heptane sprays are numerically simulated with a skeletal chemical mechanism. The influences of the droplet diameter and total equivalence on oblique detonation are considered. The initiation length is found to increase first and then decrease with increasing initial droplet diameter, and the effect of droplet size is maximized when the initial droplet diameter is approximately $10\ \mathrm {\mu } {\rm m}$ . As the initial droplet diameter varies, unsteady and steady ODWs are observed. In the cases of unsteady ODWs, temperature gradients and non-uniform distributions of the reactant mixture due to droplet evaporation lead to formation of unsteady detonation propagation, therefore leading to fluctuations in the initiation length. The fluctuations in initiation length decrease as the pre-evaporation gas equivalence ratio increases for the unsteady cases. The results further suggest that the relationship between the evaporation layer thickness along the streamline and the corresponding theoretical initiation length can be used to identify an unsteady or steady ODW in cases with large droplets that evaporate behind an oblique shock wave or ODW under the effects of different initial droplet diameters.

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“…Fang et al [23] focused on the formation and characteristic parameters of the oblique detonation wave with inhomogeneous mixing of hydrogen and air inflow for a better understanding of oblique detonation wave engine performance under practical operating conditions. Bachman and Goodwin [24] presented a new ignition criterion curve that was added to the traditional stability limits in order to include the effects of chemical kinetic timescales and wedge surface length on the prediction of ignition and formation of ODWs. This ignition criterion was demonstrated to accurately predict formation and ignition location of an ODW on an inviscid wedge surface.…”

Section: Introductionmentioning

confidence: 99%

On the evolutions of triple point structure in wedge-stabilized oblique detonations

et al. 2022

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The oblique detonation induced by a two-dimensional semi-infinite wedge is simulated numerically with the Navier-Stokes equations and a detailed H2/air reaction model based on the open source program AMROC Adaptive Mesh Refinement in Object-oriented C++. A spatially seventh-order-accurate WENO scheme is adopted for the convective flux discretization. The formation and evolution of the oblique detonation induced by wedges at different angles and inflow conditions are investigated and a prediction model for oblique detonation flow field is proposed. The results show that the formation of oblique detonation flow field can be divided into two processes. The first process is similar to the oblique shock flow field with unreactive inflow. When the inflow passes through the wedge, the oblique shock wave starts to form at the tip, followed by the unstable curved shock surface and triple point. In this process, a thin reaction layer is formed on the wedge front, but the thickness of the reaction layer is almost constant. The second process is similar to DDT. As the reaction rate increases, the deflagration front is fixed on the wedge, the reaction layer thickens, and the deflagration front gradually approaches the oblique shock wave. When the deflagration front is coupled with the oblique shock wave, the oblique detonation is formed. Moreover, a theoretical prediction model for the triple point location is proposed. Compared with the numerical simulation results, the theoretical model prediction for the position of the transition point of OSW-ODW is relatively acceptable.

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Ignition criteria and the effect of boundary layers on wedge-stabilized oblique detonation waves

Cited by 32 publications

References 34 publications

Stabilized detonation for hypersonic propulsion

Stabilized detonation for hypersonic propulsion

Propagation instabilities of the oblique detonation wave in partially prevaporized n-heptane sprays

On the evolutions of triple point structure in wedge-stabilized oblique detonations

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