Active control of thermoacoustic fluctuations by nanosecond repetitively pulsed glow discharges

Alkhalifa, Ammar M.; Alsalem, Abdulrahman; Cont-Bernard, Davide Del; Lacoste, Déanna A.

doi:10.1016/j.proci.2022.06.013

Cited by 14 publications

(3 citation statements)

References 21 publications

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“…Along with the plasma type, the way plasma is introduced to the flame is also a governing factor of PAC pathways. Plasma have been applied upstream of [15,16], in [19,38], or downstream of the flame [39,40]. In recent years, a concept of plasma-assisted ignition-stabilized combustion has been proposed [14,[41][42][43].…”

Section: Introductionmentioning

confidence: 99%

On pulse-to-pulse coupling in low-temperature filamentary plasma-assisted ignition in methane-air flows

Patel

Oijen

Nijdam

et al. 2023

Plasma Sources Sci. Technol.

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This work aims to characterize the effects of pulse repetition rate and flow speed on dielectric barrier discharge (DBD) plasma pulse-to-pulse coupling and its ability to ignite methane-air flows. Experiments are performed on a homemade DBD flow reactor with 5 mm discharge gap. Pressure and equivalence ratio are kept constant at 700 mbar and 0.6. First, we perform high-speed intensified imaging to visualize pulse-to-pulse plasma behavior and ignition kernel development. In air flows, plasma morphology changes from multiple weak filaments to a few stronger filaments indicating plasma pulse-to-pulse coupling. This leads to plasma energy addition in nearly thesame gas volume as the previous discharge. The study performed in methane-air flows highlights the importance of plasma pulse-to-pulse coupling for ignition. We find a critical pulse repetition rate and a minimum number of pulses required to achieve a strong enough coupling to develop a successful ignition kernel. Ignition probability and kernel growth are also evaluated for various conditions. Finally, plasma pulse-to-pulse coupling is quantified by measuring the plasma parameters such as gas temperature and reduced electric field from an optical emission spectroscopy.

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Section: Introductionmentioning

confidence: 99%

On pulse-to-pulse coupling in low-temperature filamentary plasma-assisted ignition in methane-air flows

Patel

Oijen

Nijdam

et al. 2023

Plasma Sources Sci. Technol.

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“…applications [1,2]. Non-thermal plasma, produced by nanosecond repetitively pulsed (NRP) discharges, has garnered significant interest due to its ability to enhance ignition, extend flammability, stabilize flames, and accelerate low-temperature fuel oxidation for a broad spectrum of hydrocarbon fuels, while using only a minimal amount of input electrical energy [3][4][5][6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

A computational study of a laminar methane–air flame assisted by nanosecond repetitively pulsed discharges

Shao,

Kabbaj,

Lacoste

et al. 2024

J. Phys. D: Appl. Phys.

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Nanosecond repetitively pulsed (NRP) discharges have been considered a promising technique for enhancing combustion efficiency and control. For successful implementation, it is necessary to understand the complex plasma-combustion interactions involving chemical, thermal, and hydrodynamic pathways. This paper aims to investigate the mechanisms enhancing a laminar methane-air flame assisted by NRP discharges by high fidelity simulations of the jet-wall burner employed in a previous experimental study. A phenomenological plasma model is used to represent the plasma energy deposition in two channels: 1) the ultrafast heating and dissociation of O2 resulting from the relaxation of electronically excited N2, and 2) slow gas heating stemming from the relaxation of N2 vibrational states. The flame displacement, key radical distribution and flame response under plasma actuation are compared with experimental results in good agreement. The computational model allows a systematic investigation of the dominant physical mechanism by isolating different pathways. It is found that the kinetic effect from atomic O production dominates the flame dynamics, while the thermal effect plays a minor role. Hydrodynamic perturbations arising from weak shock wave propagation appear to be sensitive to burner geometry and is found to be insignificant in the case under study.

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“…However, due to significant heating of the gas, they contribute to increasing nitric oxide (NO) emissions when applied to flames [16,17]. Similarly, NRP glow discharges can enhance combustion [18][19][20]. It was demonstrated that NRP glow discharges can enhance turbulent flames at pressures up to 5 bar, which are relevant for gas turbine engines [19].…”

Section: Introductionmentioning

confidence: 99%

Quantifying the thermal effect and methyl radical production in nanosecond repetitively pulsed glow discharges applied to a methane-air flame

M Alkhalifa,

Di Sabatino,

A Steinmetz

et al. 2024

J. Phys. D: Appl. Phys.

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In this work, we investigated non-equilibrium plasma produced by nanosecond repetitively pulsed glow discharges applied across a lean premixed methane-air flame. The flame is stationary, axisymmetric, and laminar. The discharges are applied on the symmetry axis crossing the reactant gases, flame front, and product gases, allowing phase-locked averaged measurements and comparisons with axisymmetric numerical simulations. The thermal effect and methyl radical production are quantified in the discharge in the reactant gas region. One-dimensional, two-beam, hybrid, femtosecond-picosecond, coherent anti-Stokes Raman scattering is used to acquire spatial and temporal profiles of temperature and oxygen-to-nitrogen concentration ratio. Photo-fragmentation laser-induced fluorescence is used to acquire quantitative two-dimensional profiles of methyl radicals in the discharge providing the first quantitative imaging of methyl produced ahead of a flame by plasma-induced methane dissociation. The spatial profiles of temperature and oxygen-to-nitrogen concentration ratio are in steady state, indicating that individual discharges have an insignificant heating effect. Upper and lower bounds of the produced mole fraction of methyl radicals in the plasma are obtained due to uncertainties in the collisional quenching rates of excited state methylidyne radicals in the plasma. The discharges produce a maximum of 600–1100 ppm of methyl radicals upstream of the flame front within 25 ns. This amount is similar to the predicted methyl mole fraction for the flame without plasma and thus represents a significant chemical perturbation to the reactants upstream of the flame front. The produced methyl follows an exponential decay in the first microsecond after the discharge with a decay constant of 8 µs close to the flame, and 0.8 µs further from the flame. The decay then deviates from the exponential curve and the methyl persists for tens of microseconds. The results suggest that for the tested configuration, the thermal effect of individual discharges through fast gas heating is negligible, while active chemical species are produced in large quantities in the reactant gases, upstream of the flame front.

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Active control of thermoacoustic fluctuations by nanosecond repetitively pulsed glow discharges

Cited by 14 publications

References 21 publications

On pulse-to-pulse coupling in low-temperature filamentary plasma-assisted ignition in methane-air flows

On pulse-to-pulse coupling in low-temperature filamentary plasma-assisted ignition in methane-air flows

A computational study of a laminar methane–air flame assisted by nanosecond repetitively pulsed discharges

Quantifying the thermal effect and methyl radical production in nanosecond repetitively pulsed glow discharges applied to a methane-air flame

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