Influence of Plasma on the Combustion Mode in a Scramjet

Meng, Yu; Gu, Hongbin; Chen, Fang

doi:10.3390/aerospace9020073

Cited by 11 publications

(3 citation statements)

References 48 publications

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“…The base vacuum pressure is approximately 1% of the experimental pressure (∼30 mTorr), and thus the plasma contains impurities such as hydroxyl radicals (OH) which originate from the water vapor on the wall of the vacuum chamber. The line emissions from the trace amount of OH molecules are employed to measure the rotational and vibrational temperatures by fitting them with the LIFBASE simulation [38][39][40][41]. As the experimental resolution is about 0.6 ± 0.3 nm, the line emissions are compared with the simulation data that are relatively filtered, and the best fit gives the temperature estimation for a given pressure with a maximum error of about 15%.…”

Section: The Hysteresis In the Rotational And Vibrational Temperaturesmentioning

confidence: 99%

Mode transition (α–γ) and hysteresis in microwave-driven low-temperature plasmas

Kyungtae¹,

Nam²,

Lee³

et al. 2022

Plasma Sources Sci. Technol.

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We discovered a hysteresis in a microwave-driven low-pressure argon plasma during gas pressure change across the transition region between α and γ discharge modes. The hysteresis is manifested in that the critical pressure of mode transition depends on the direction of pressure change. As a corollary, the plasma would attain different discharge properties under the same operating parameters (pressure, power, and gas composition), suggesting a bi-stability or existence of memory effect. Analysis of the rotational and vibrational temperatures measured from the OH (A-X) line emissions shows that the hysteresis is mainly due to the fast gas heating in the γ-mode leading to a smaller neutral density than that of the α-mode. When increasing the gas pressure, the γ-mode discharge maintains a relatively higher temperature and lower neutral density, and thus, it requires a higher operating pressure to reach the α-mode. On the other hand, decreasing the pressure while maintaining α-mode, the transition to γ-mode occurs at a lower pressure than the former case due to a relatively higher neutral density of α-mode discharge. This interpretation is supported by the fact that the hysteresis disappears when the plasma properties are presented with respect to the neutral gas density instead of pressure.

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Section: The Hysteresis In the Rotational And Vibrational Temperaturesmentioning

confidence: 99%

Mode transition (α–γ) and hysteresis in microwave-driven low-temperature plasmas

Kyungtae¹,

Nam²,

Lee³

et al. 2022

Plasma Sources Sci. Technol.

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show abstract

“…As for supersonic combustion, the interaction between nanosecond discharge and air flow should be addressed. Meng [18] conducted an experimental study of plasma-assisted supersonic combustion using gliding arc discharge. The results show that plasma free-radical mechanisms cause changes to combustion modes.…”

Section: Introductionmentioning

confidence: 99%

A Numerical Investigation of Supersonic Combustion Flow Control by Nanosecond-Pulsed Actuations

Yan,

Wang,

Lan

et al. 2023

Energies

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The efficiency of supersonic combustion is largely dependent on inlet and injection parameters. Additional energy input is required in some off-design conditions, and nanosecond discharge actuation can be a solution. In the present study, a phenomenological model of a nanosecond-pulsed surface dielectric barrier discharge (NS-SDBD) actuator was developed to analyze the combustion enhancement effect for a supersonic combustor with transverse H2 injection. A seven-reaction H2–air combustion model was adopted for the numerical simulation. Dynamic mode decomposition (DMD) was employed to acquire temperature perturbation in spatial and temporal domains. The results show that the actuator provides additional temperature-increment and species transportation through compression waves. The combustion enhancement effect is mainly attributed to the flow perturbation in the shear layer, which promotes the turbulent diffusion of fuel. Given the same power input, the combustion efficiency at the shockwave reflection point is increased by 17.5%, and the flame height is increased by 15.4% at its maximum.

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“…In the 1990s, the Russian Central Institute of Aviation Motors (CIAM) first used the cavity as a flame stabilizer in a hydrogenfueled dual-mode scramjet flight experiment jointly conducted with France [9,10]. However, supersonic combustion is an unsteady process, and combustion oscillations may be caused by many factors, such as a specific equivalence ratio, acceleration, and deceleration [11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Supersonic Combustion Mode Analysis of a Cavity Based Scramjet

Meng

Sun

et al. 2022

Aerospace

Self Cite

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Since flame stability is the key to the performance of scramjets, scramjet combustion mode and instability characteristics were investigated by using the POD method based on a cavity-stabilized scramjet. Experiments were developed on a directly connected scramjet model that had an inlet flow of Mach 2.5 with a cavity stabilizer. CH* chemiluminescence, schlieren, and a wall static pressure sensor were employed to observe flow and combustion behavior. Three typical combustion modes were classified by distinguishing averaged CH* chemiluminescence images of three ethylene fuel jet equivalence ratios. The formation reason was explained using schlieren images and pressure characteristics. POD modes (PDMs) were determined using the proper orthogonal decomposition (POD) of sequential flame CH* chemiluminescence images. The PSD (power spectral density) of the PDM spectra showed large peaks in a frequency range of 100–600 Hz for three typical stabilized combustion modes. The results provide oscillation characteristics of three scramjet combustion modes.

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Influence of Plasma on the Combustion Mode in a Scramjet

Cited by 11 publications

References 48 publications

Mode transition (α–γ) and hysteresis in microwave-driven low-temperature plasmas

Mode transition (α–γ) and hysteresis in microwave-driven low-temperature plasmas

A Numerical Investigation of Supersonic Combustion Flow Control by Nanosecond-Pulsed Actuations

Supersonic Combustion Mode Analysis of a Cavity Based Scramjet

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