Assessment of the impact of nanosecond plasma discharge on the combustion of methane air flames

Fontanarosa, Donato; Mehdi, Ghazanfar; Giorgi, Maria Grazia De; Ficarella, Antonio

doi:10.1051/e3sconf/202019710001

Cited by 7 publications

(6 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, the EN value for the single pulse was about 200 Td for Case 1. In our previous study, we found that the ignition has been significantly improved at 200 Td [40]. Similar results were also observed by [41] at the same EN value.…”

Section: Electrical Characterizationsupporting

confidence: 85%

Effects of Nanosecond Repetitively Pulsed Discharges Timing for Aeroengines Ignition at Low Temperature Conditions by Needle-Ring Plasma Actuator

2021

Self Cite

View full text Add to dashboard Cite

These days, various national and international research organizations are working on the development of low NOx combustors. The present work describes the experimental and numerical characterization of flow dynamics and combustion characteristics in a rectangular burner. A ring-needle type plasma actuator was developed and driven by a high voltage nanosecond pulsed generator under atmospheric conditions. Smoke flow visualizations and Proper Orthogonal Decomposition (POD) were carried out to identify the relevant flow structures. Electrical characterization of the non-reactive flow was carried out to predict the electrical power and the optimum value of the reduced electric field (EN), which is useful for the implementation of a numerical model for the study of plasma-assisted ignition. A detailed plasma kinetic mechanism integrated with all excited species was considered and validated with experimental studies. Numerical modeling of plasma ignition has been performed by coupling ZDPlasKin with CHEMKIN. Energy and power consumption for methane/air plasma actuation is higher than the air plasma actuation. This could be due to the excitation and ionization of methane that required more energy deposition and power. The mole fraction of O atoms and ozone was higher in the air than the methane/air actuation. However, O atoms were produced in a very short time interval of 10−7 to 10−6 s; in contrast, the concentration of ozone was gradually increased with the time interval and the peak was observed around 10−1 s. Plasma discharges on the methane/air mixture also produced radicals that played a key role to enhance the combustion process. It was noticed that the concentration of H species was high among all radicals with a concentration of nearly 10−1. The concentration peak of CH3 and OH was almost the same in the order of 10−2. Finally, the mixture ignition characteristics under different low inlet temperatures were analyzed for both air and methane/air plasma actuation in the presence of different plasma discharges pulses numbers. Results showed that it is possible to reach flame ignition at inlet temperature lower than the minimum required in the absence of plasma actuation, which means ignition is possible in cold flow, which could be essential to address the re-ignition problems of aeroengines at high altitudes. At Ti = 700 K, the ignition was reached only with plasma discharges; ignition time was in the order of 0.01 s for plasma discharges on methane/air, lower than in case of plasma in air, which permitted ignition at 0.018 s. Besides this, in the methane/air case, 12 pulses were required to achieve successful ignition; however, in air, 19 pulses were needed to ignite.

show abstract

Section: Electrical Characterizationsupporting

confidence: 85%

Effects of Nanosecond Repetitively Pulsed Discharges Timing for Aeroengines Ignition at Low Temperature Conditions by Needle-Ring Plasma Actuator

2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…The closed homogenous batch reactor was used for the ignition analysis. The detailed description of numerical procedure and experimental validation of extended version of mechanism has been presented in our previously published articles [22,23].…”

Section: Numerical Proceduresmentioning

confidence: 99%

“…The mean integral value of E N in the time interval of 10 −6 was about 200 Td. This value has been previously proved to improve the combustion characteristic time of methane flame [22][23][24]. Therefore, numerical analysis of ignition characteristics has been performed by considering the electrical output of Test 2.…”

Section: Electrial Characterizationmentioning

confidence: 99%

“…This happens through collisions between energetic electrons and abundant particles such as diatomic nitrogen and oxygen, finally leading to the generation of radicals that promote ignition. In our previous studies, it has been noticed that the deposition of nanopulsed plasma discharge decomposed the methane/air and improved the concentrations of neutral radicals such as H, CH, OH, CH 3 , O, and O 3 by following the electron impact reactions [22][23][24]. In this paper, numerical analysis of neutral radicals has been performed at different inlets pressure aiming to see particularly the effects on concentration of particles at low pressure.…”

Section: Production Of Active Particlesmentioning

confidence: 99%

See 1 more Smart Citation

Plasma Assisted Re-Ignition of Aeroengines under High Altitude Conditions

2022

Self Cite

View full text Add to dashboard Cite

Re-ignition of aeroengines under high altitude conditions is of great importance to the safety and use of lean-burn flame. This study is focused on the experimental and numerical characterization of flow dynamics and flame re-ignition in a rectangular burner. A ring-needle type plasma actuator was considered and run by high-voltage (HV) nanopulsed plasma generator. The electrical power delivered to the fluid and an optimal value of reduced electric field (EN) was calculated considering non-reactive flow. Smoke flow visualizations using a high-speed camera and proper orthogonal decomposition (POD) were performed to recognize the most dominant flow structures. Experimental results revealed the transport effects due to plasma discharge, such as the induced flow, that could have a strong impact on the recirculation zone near the corners of combustor, improving the mixing performance and reducing the ignition delay time. Two different numerical tools (ZDPlasKin and Chemkin) were used to investigate the ignition characteristics. ZDPlasKin calculated the thermal effect and the plasma kinetic of nanopulsed plasma discharge at the experimentally measured EN. Finally, based on the output of ZDPlasKin, Chemkin estimated the flame ignition at low pressure and low temperature conditions. It was noticed that time required to achieve the maximum flame temperature with plasma actuation is significantly less than the auto-ignition time (‘clean case’, simulation result of the model without considering the plasma effect). Maximum reduction in ignition time was observed at inlet pressure 1 bar (3.5 × 10−5 s) with respect to the clean case (1.1 × 10−3 s). However, as the inlet pressure is reduced, the ignition delay time was increased. At 0.6 bar flame ignition occurred in clean case at 0.0048 s and at 0.0022 s in presence of the plasma actuation, a further decrease of the pressure up to 0.4 bar leads the ignition at 0.0027 s and 0.0063 s in clean and plasma actuation, respectively.

show abstract

“…Plasma assisted combustion (PAC) is a prominent and evolving technology devoted to the enhancement of the combustion efficiency, by extending the lean blow out limit, improving the flame stability, and allowing for low temperature oxidation and the simultaneous reduction of nitrogen oxides (NO x ) [1,2]. PAC has great potential to improve ignition and combustion by three ways via thermal (rise in temperature), kinetic (production of excited species, electron, ions and neutral radicals) and transport (fuel decomposition and reforming) [3,4].…”

Section: Introductionmentioning

confidence: 99%

Ozone Production With Plasma Discharge: Comparisons Between Activated Air and Activated Fuel/Air Mixture

Mehdi

Giorgi

Fontanarosa

et al. 2021

Volume 3B: Combustion, Fuels, and Emissions

View full text Add to dashboard Cite

This study focused on the comparative analysis about the production of ozone and active radicals in presence of nanopulsed plasma discharge on air and on fuel/air mixture to investigate its effect on combustion enhancement. This analysis is based on numerical modeling of air and methane/air plasma discharge with different repetition rates (100 Hz, 1000 Hz and 10000 Hz). To this purpose, a two-step approach has been proposed based on two different chemistry solvers: a 0-D plasma chemistry solver (ZDPlasKin toolbox) and a combustion chemistry solver (CHEMKIN software suite). Consequently, a comprehensive chemical kinetic scheme was generated including both plasma excitation reactions and gas phase reactions. Validation of air and methane/air mechanisms was performed with experimental data. Kinetic models of both air and methane/air provides good fitting with experimental data of O atom generation and decay process. ZDPlasKin results were introduced in CHEMKIN in order to analyze combustion enhancement. It was found that the concentrations of O3 and O atom in air are higher than the methane/air activation. However, during the air activation peak concentration of ozone was significantly increased with repetition rates and maximum was observed at 10000 Hz. Furthermore, ignition timings and flammability limits were also improved with air and methane/air activation but the impact of methane/air activation was comparatively higher.

show abstract

Assessment of the impact of nanosecond plasma discharge on the combustion of methane air flames

Cited by 7 publications

References 20 publications

Effects of Nanosecond Repetitively Pulsed Discharges Timing for Aeroengines Ignition at Low Temperature Conditions by Needle-Ring Plasma Actuator

Effects of Nanosecond Repetitively Pulsed Discharges Timing for Aeroengines Ignition at Low Temperature Conditions by Needle-Ring Plasma Actuator

Plasma Assisted Re-Ignition of Aeroengines under High Altitude Conditions

Ozone Production With Plasma Discharge: Comparisons Between Activated Air and Activated Fuel/Air Mixture

Contact Info

Product

Resources

About