Self-sustained, high-frequency detonation wave generation in a semi-bounded channel

Schwinn, Kyle S.; Gejji, Rohan; Kan, Brandon; Sardeshmukh, Swanand V.; Heister, Stephen D.; Slabaugh, Carson D.

doi:10.1016/j.combustflame.2018.03.022

Cited by 51 publications

(4 citation statements)

References 24 publications

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“…Therefore, we speculate that new DWs spontaneously form when DDTs occur via chemical reactions at the contact surface. A similar phenomenon was observed by Schwinn et al (2018) in their experimental study of an "unwrapped" RDE configuration. They referred to the phenomenon as "auto-ignition.…”

Section: Four-wave Modesupporting

confidence: 81%

Operational mode transition in a rotating detonation engine

Lei

Chen

Yang

et al. 2020

J. Zhejiang Univ. Sci. A

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The relationship between the number of detonation waves and the evolution process of the flow field in a rotating detonation engine was investigated through a numerical analysis. The simulations were based on the Euler equation and a detailed chemical reaction model. In the given engine model, the flow-field evolution became unstable when a single detonation wave was released. New detonation waves formed spontaneously, changing the operational mode from single-wave to four-wave. However, when two or three detonation waves were released, the flow field evolved in a quasi-steady manner. Further study revealed that the newly formed detonation wave resulted from an accelerated chemical reaction on the contact surface between the detonation products and the reactive mixture. To satisfy the stable propagation requirements of detonation waves, we proposed a parameter called NL, which can be compared with the number of detonation waves in the combustor to predict the evolution (quasi-stable or unstable) of the flow field. Finally, we verified the effectiveness of NL in a redesigned engine. This study may assist the operational mode control in rotating detonation engine experiments.

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Section: Four-wave Modesupporting

confidence: 81%

Operational mode transition in a rotating detonation engine

Lei

Chen

Yang

et al. 2020

J. Zhejiang Univ. Sci. A

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“…Once the burned gases are purged, the cycle repeats. The minimum cycle frequency to ensure performance above classical combustion (deflagration) is 75 Hz [7], and the state-of-the-art devices range between 100 and 400 Hz [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Experimental Pressure Gain Analysis of Pulsed Detonation Engine

Bogoi,

Cuciuc,

Cojocea

et al. 2024

Aerospace

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A pulsed detonation chamber (PDC) equipped with Hartmann–Sprenger resonators has been designed and tested for both Hydrogen/air and Hydrogen/Oxygen mixtures. A full-factorial experimental campaign employing four factors with four levels each has been carried out for both mixtures. Instantaneous static pressure has been measured at two locations on the exhaust pipe of the PDC, and the signal has been processed to extract the average and maximum cycle pressures and the operating frequency of the spark plug. The PDC has been shown to be able to reach sustained detonation cycles over a length below 200 mm, measured from the spark plug to the first pressure sensor. The optimal regimes for both air and Oxygen operation have been determined, and the influence of the four factors on the responses is discussed.

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“…We study the spatio-temporal and spectro-temporal evolution of such finite amplitude planar nonlinear acoustic waves in three canonical configurations in particular: traveling waves (TW), standing waves (SW), and randomly initialized Acoustic Wave Turbulence (AWT). In spite of it's theoretical nature, planar nonlinear acoustic theory is still commonly used in practical investigations such as sonic boom propagation (TW) [18], rotating detonation engines (SW) [19], combustion chamber noise (AWT) [20], and thermoacoustics [16,17]. We study these configurations for pressure amplitudes and viscosities spanning three orders of magnitudes.…”

Section: Introductionmentioning

confidence: 99%

Spectral energy cascade and decay in nonlinear acoustic waves

Gupta

Scalo

2018

Phys. Rev. E

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We present a numerical and theoretical investigation of nonlinear spectral energy cascade of decaying finite-amplitude planar acoustic waves in a single-component ideal gas at standard temperature and pressure (STP). We analyze various one-dimensional canonical flow configurations: a propagating traveling wave (TW), a standing wave (SW), and randomly initialized Acoustic Wave Turbulence (AWT). Due to nonlinear wave propagation, energy at the large scales cascades down to smaller scales dominated by viscous dissipation, analogous to hydrodynamic turbulence. We use shock-resolved mesh-adaptive direct numerical simulations (DNS) of the fully compressible onedimensional Navier-Stokes equations to simulate the spectral energy cascade in nonlinear acoustic waves. The simulation parameter space for the TW, SW, and AWT cases spans three orders of magnitude in initial wave pressure amplitude and dynamic viscosity, thus covering a wide range of both spectral energy cascade and the viscous dissipation rates. The shock waves formed as a result of energy cascade are weak (M < 1.4), and hence we neglect thermodynamic non-equilibrium effects such as molecular vibrational relaxation in the current study. We also derive a new set of nonlinear acoustics equations truncated to second order and the corresponding perturbation energy corollary yielding the expression for a new perturbation energy norm E (2) . Its spatial average, satisfies the definition of a Lyapunov function, correctly capturing the inviscid (or lossless) broadening of spectral energy in the initial stages of evolution -analogous to the evolution of kinetic energy during the hydrodynamic break down of three-dimensional coherent vorticity -resulting in the formation of smaller scales. Upon saturation of the spectral energy cascade i.e. fully broadened energy spectrum, the onset of viscous losses causes a monotonic decay of in time. In this regime, the DNS results yield ∼ t −2 for TW and SW, and ∼ t −2/3 for AWT initialized with white noise. Using the perturbation energy corollary, we derive analytical expressions for the energy, energy flux, and dissipation rate in the wavenumber space. These yield the definitions of characteristic length scales such as the integral length scale (characteristic initial energy containing scale) and the Kolmogorov length scale η (shock thickness scale), analogous to K41 theory of hydrodynamic turbulence (A. N. Kolmogorov, Dokl. Akad. Nauk SSSR 30 , 9 (1941)). Finally, we show that the fully developed energy spectrum of the nonlinear acoustic waves scales as E k k 2 −2/3 1/3 ∼ C f (kη), with C ≈ 0.075 constant for TW and SW but decaying in time for AWT. arXiv:1809.02202v1 [physics.flu-dyn]

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Self-sustained, high-frequency detonation wave generation in a semi-bounded channel

Cited by 51 publications

References 24 publications

Operational mode transition in a rotating detonation engine

Operational mode transition in a rotating detonation engine

Experimental Pressure Gain Analysis of Pulsed Detonation Engine

Spectral energy cascade and decay in nonlinear acoustic waves

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