Investigation of the Exhaust Flow of a Pulse Detonation Combustor at different Operating Conditions based on High-Speed Schlieren and PIV

Haghdoost, Mohammad Rezay; Edgington-Mitchell, Daniel; Paschereit, Christian Oliver; Oberleithner, Kilian

doi:10.2514/6.2019-1512

Cited by 4 publications

(5 citation statements)

References 51 publications

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“…Consider the series of time-resolved schlieren images of a starting jet produced by a deflagration-detonation-transition presented in Figure 30. 223,224 Here the vortex in question is the starting-vortex, rather than a typical shear layer vortex, and is thus far stronger than those observed in steady jets, which makes the Figure 29. Schematic representation of a vortex interacting with a stationary shock, based on the numerical results of Grasso and Pirozzoli.…”

Section: 22mentioning

confidence: 94%

“…Consider the series of time-resolved schlieren images of a starting jet produced by a deflagration-detonation-transition presented in Figure 30. 223,224 Here the vortex in question is the starting-vortex, rather than a typical shear layer vortex, and is thus far stronger than those observed in steady jets, which makes the phenomenon easier to visualize. The first image (half of which is replaced with a schematic representation), shows a typical triple shock formation characteristic of an underexpanded jet, but with the reflected shock terminating in the leading vortex ring.…”

Section: The Four Fundamental Mechanisms Of Resonant Self-excitationmentioning

confidence: 99%

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Aeroacoustic resonance and self-excitation in screeching and impinging supersonic jets – A review

Edgington-Mitchell

2019

International Journal of Aeroacoustics

172

104

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Supersonic jets, particularly shock-containing jets, often exhibit high-intensity, discrete-frequency acoustic tones. These tones are the signature of an aeroacoustic resonance loop established by the flow. This paper considers two of the classical forms of supersonic jet resonance: screech in shock-containing free jets and tones generated by the impingement of a jet against a surface. The first half of the paper provides a historical perspective on research into both forms of resonance, ranging from the seminal works of Alan Powell to recent contributions from high-fidelity numerical simulation, experiment, and stability theory. The second half of the paper provides a critical assessment of current understanding around the four processes that characterize jet resonance: a downstream propagation of energy, an acoustic generation mechanism, an upstream propagation of energy, and a receptivity mechanism.

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Section: 22mentioning

confidence: 94%

“…Consider the series of time-resolved schlieren images of a starting jet produced by a deflagration-detonation-transition presented in Figure 30. 223,224 Here the vortex in question is the starting-vortex, rather than a typical shear layer vortex, and is thus far stronger than those observed in steady jets, which makes the phenomenon easier to visualize. The first image (half of which is replaced with a schematic representation), shows a typical triple shock formation characteristic of an underexpanded jet, but with the reflected shock terminating in the leading vortex ring.…”

Section: The Four Fundamental Mechanisms Of Resonant Self-excitationmentioning

confidence: 99%

Aeroacoustic resonance and self-excitation in screeching and impinging supersonic jets – A review

Edgington-Mitchell

2019

International Journal of Aeroacoustics

172

104

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“…The pulse detonation engine (PDE) has been the focus of propulsion research efforts in the last few decades, due to its potential to drastically increase the efficiency when compared to conventional gas turbines [1][2][3]. In a hybrid-PDE configuration, an annular array of pulse detonation combustors (PDCs) replaces conventional isobaric combustion weaker shock waves.…”

Section: Introductionmentioning

confidence: 99%

Numerical and experimental evaluation of shock dividers

et al. 2022

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Mitigation of pressure pulsations in the exhaust of a pulse detonation combustor is crucial for operation with a downstream turbine. For this purpose, a device termed the shock divider is designed and investigated. The intention of the divider is to split the leading shock wave into two weaker waves that propagate along separated ducts with different cross sections, allowing the shock waves to travel with different velocities along different paths. The separated shock waves redistribute the energy of the incident shock wave. The shock dynamics inside the divider are investigated using numerical simulations. A second-order dimensional split finite volume MUSCL-scheme is used to solve the compressible Euler equations. Furthermore, low-cost simulations are performed using geometrical shock dynamics to predict the shock wave propagation inside the divider. The numerical simulations are compared to high-speed schlieren images and time-resolved total pressure recording. For the latter, a high-frequency pressure probe is placed at the divider outlet, which is shown to resolve the transient total pressure during the shock passage. Moreover, the separation of the shock waves is investigated and found to grow as the divider duct width ratio increases. The numerical and experimental results allow for a better understanding of the dynamic evolution of the flow inside the divider and inform its capability to reduce the pressure pulsations at the exhaust of the pulse detonation combustor.

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“…The first stage of the jet evolution is the well known shock-diffraction phenomenon, which has been investigated numerically, experimentally and analytically by many researchers [1][2][3][4]. The next stage is the dynamic evolution of a highly transient supersonic trailing jet behind the leading shock, which has also received significant attention [5][6][7][8][9][10][11]. However, both the numerical and experimental study of the flow at this stage is inherently challenging [12,13] due to the short timescales and large dynamic ranges involved.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Evolution of a Transient Supersonic Trailing Jet Induced by a Strong Incident Shock Wave

Haghdoost¹,

Edgington-Mitchell²,

Nadolski³

et al. 2019

Preprint

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The dynamic evolution of a highly underexpanded transient supersonic jet at the exit of a pulse detonation engine is investigated via high-resolution time-resolved schlieren and numerical simulations. Experimental evidence is provided for the presence of a second triple shock configuration along with a shocklet between the reflected shock and the slipstream, which has no analogue in a steady-state underexpanded jet. A pseudo-steady model is developed, which allows for the determination of the post-shock flow condition for a transient propagating oblique shock. This model is applied to the numerical simulations to reveal the mechanism leading to the formation of the second triple point. Accordingly, the formation of the triple point is initiated by the transient motion of the reflected shock, which is induced by the convection of the vortex ring. While the vortex ring embedded shock move essentially as a translating strong oblique shock, the reflected shock is rotating towards its steady state position. This results in a pressure discontinuity that must be resolved by the formation of a shocklet.

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Investigation of the Exhaust Flow of a Pulse Detonation Combustor at different Operating Conditions based on High-Speed Schlieren and PIV

Cited by 4 publications

References 51 publications

Aeroacoustic resonance and self-excitation in screeching and impinging supersonic jets – A review

Aeroacoustic resonance and self-excitation in screeching and impinging supersonic jets – A review

Numerical and experimental evaluation of shock dividers

Dynamic Evolution of a Transient Supersonic Trailing Jet Induced by a Strong Incident Shock Wave

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