Journal articles on the topic 'Combustion instabilitiely pulsed plasma discharges'
To see the other types of publications on this topic, follow the link: Combustion instabilitiely pulsed plasma discharges.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 20 journal articles for your research on the topic 'Combustion instabilitiely pulsed plasma discharges.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Starikovskii, Andrei Y., Nikolay B. Anikin, Ilya N. Kosarev, Eugeny I. Mintoussov, Maria M. Nudnova, Aleksandr E. Rakitin, Dmitry V. Roupassov, Svetlana M. Starikovskaia, and Victor P. Zhukov. "Nanosecond-Pulsed Discharges for Plasma-Assisted Combustion and Aerodynamics." Journal of Propulsion and Power 24, no. 6 (November 2008): 1182–97. http://dx.doi.org/10.2514/1.24576.
2
Deng, Jiangge, Ting Li, Jinkui Wang, and Chicheng Gao. "Experimental Study of Suppressing the Thermoacoustic Instabilities in a Rijke Tube Using Microsecond Discharge Plasma." Aerospace 9, no. 12 (December 16, 2022): 836. http://dx.doi.org/10.3390/aerospace9120836.
Abstract:
Thermoacoustic instabilities occur when heat release is coupled with pressure fluctuation, which may cause performance degradation of the combustor and serious structural damage. This study focued on an active control method using discharge plasma and showed experimentally that discharge plasma can make a difference in controlling the thermoacoustic instabilities in a Rijke tube. A vertically placed Rijke tube thermoacoustic system using induction heating tungsten mesh as a heat source was built. The results show that the high repetition rate discharge can effectively suppress the thermoacoustic oscillations in the Rijke tube and that they will not re-occur for some time. Additionally, their effectiveness depended more on average power than energy per pulse. Combining the collected pressure, schlieren data, and theoretical analysis, it can be suggested that the plasma discharge could heat the inlet airflow, which could influence the heat exchange and then could break thermo-acoustic coupling, and its high-frequency pressure perturbation might increase the dissipation of the energy of sound.
3
Starikovskii, A. Yu, N. B. Anikin, I. N. Kosarev, E. I. Mintoussov, S. M. Starikovskaia, and V. P. Zhukov. "Plasma-assisted combustion." Pure and Applied Chemistry 78, no. 6 (January 1, 2006): 1265–98. http://dx.doi.org/10.1351/pac200678061265.
Abstract:
This paper presents an overview of experimental and numerical investigations of the nonequilibrium cold plasma generated under high overvoltage and further usage of this plasma for plasma-assisted combustion.Here, two different types of the discharge are considered: a streamer under high pressure and the so-called fast ionization wave (FIW) at low pressure.The comprehensive experimental investigation of the processes of alkane slow oxidation in mixtures with oxygen and air under nanosecond uniform discharge has been performed. The kinetics of alkane oxidation has been measured from methane to decane in stoichiometric and lean mixtures with oxygen and air at room temperature under the action of high-voltage nanosecond uniform discharge.The efficiency of nanosecond discharges as active particles generator for plasma-assisted combustion and ignition has been investigated. The study of nanosecond barrier discharge influence on a flame propagation and flame blow-off velocity has been carried out. With energy input negligible in comparison with the burner's chemical power, a double flame blow-off velocity increase has been obtained. A signicant shift of the ignition delay time in comparison with the autoignition has been registered for all mixtures.Detonation initiating by high-voltage gas discharge has been demonstrated. The energy deposition in the discharge ranged from 70 mJ to 12 J. The ignition delay time, the velocity of the flame front propagation, and the electrical characteristics of the discharge have been measured during the experiments. Under the conditions of the experiment, three modes of the flame front propagation have been observed, i.e., deflagration, transient detonation, and Chapman-Jouguet detonation. The efficiency of the pulsed nanosecond discharge to deflagration-to-detonation transition (DDT) control has been shown to be very high.
4
Gururajan, Vyaas, and Riccardo Scarcelli. "A nanosecond pulsed discharge circuit model for engine applications." Journal of Physics D: Applied Physics 55, no. 15 (January 24, 2022): 155205. http://dx.doi.org/10.1088/1361-6463/ac4726.
Abstract:
Abstract Non-equilibrium plasma discharges in spark gaps have been an increasingly studied method for alleviating cycle to cycle variation in lean and dilute combustion environments. However, ignition models that account for streamer propagation, cathode fall, and transmission line amplification over nanosecond time scales have so far not been developed. The present study develops such a model, with emphasis on the energy delivered from circuit to cylinder. Key pieces of the relevant physics and chemistry are summarized, simplified, and systematically coupled to one another. The set of parameters is limited to a handful of key observables and modeled using Modelica. Results show non-trivial behavior in the energy delivery characteristics of such discharges with important implications for ignition.
5
Mehdi, Ghazanfar, Sara Bonuso, and Maria Grazia De Giorgi. "Effects of Nanosecond Repetitively Pulsed Discharges Timing for Aeroengines Ignition at Low Temperature Conditions by Needle-Ring Plasma Actuator." Energies 14, no. 18 (September 14, 2021): 5814. http://dx.doi.org/10.3390/en14185814.
Abstract:
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.
6
Khlyustova, A. V., N. A. Sirotkin, A. V. Agafonov, M. A. Stepovich, and M. N. Shipko. "On the Dynamics of Development and the Results of the Action of Electric Discharge in the Aquatic Environment." Поверхность. Рентгеновские, синхротронные и нейтронные исследования, no. 2 (February 1, 2023): 57–62. http://dx.doi.org/10.31857/s1028096023020036.
Abstract:
The properties of the synthesized nanostructured materials are determined by the methods of their preparation. The combination of electric discharges with liquid is one of the new tools for the synthesis of pure structures but the conditions for obtaining structures play an important role as in the case of traditional synthesis methods. In this work, the electrical and emission characteristics of a low-temperature direct current plasma in contact with water at currents of 0.25 and 0.80 A are studied. The values of the power (energy) of single discharges are calculated. It has been established that this type of discharge burns in a pulsed mode. The value of the discharge current affects the frequency of occurrence of discharges and the energy of an single discharge. It is shown that low-temperature underwater plasma is an effective tool for the synthesis of nanocomposites based on metal oxides, the precursors of which are metal electrodes. The emission spectroscopy method was used to study the emission spectra of underwater plasma. The sputtering of electrodes during plasma combustion, has been established. X-ray phase analysis showed that the phase composition of the obtained products is determined by the strength of the plasma current. The formation of oxides and hydroxides of Ni and Cr with different valencies of metal ions was found.
7
Yang, Suo, Praise Noah Johnson, and Taaresh Sanjeev Taneja. "(Invited) Plasma-Assisted Ammonia Combustion and Flare Gas Reforming to Enhance Reactivity and Control Emission." ECS Meeting Abstracts MA2023-01, no. 20 (August 28, 2023): 1496. http://dx.doi.org/10.1149/ma2023-01201496mtgabs.
Abstract:
Increasing emphasis on the de-carbonization of energy production has led researchers to consider carbon-free, renewable, and green fuels such as hydrogen (H2) and ammonia (NH3). While H2 suffers from the major challenges of production difficulties, transportation, and storage, NH3 is plagued with challenges of low flame speeds causing unstable flames, high autoignition temperatures resulting in longer ignition delays, narrow flammability limits, and higher levels of NOx emission. Among the different solutions to overcome these challenges of NH3 combustion, non-equilibrium plasma-based igniters are significant owing to the promotion of localized volumetric ignition kernel development by both thermal and chemical assistance. Computational investigation of plasma-assisted combustion of ammonia-air mixtures in constant volume and constant pressure reactors are conducted, to determine the impact of operating conditions on ignition delays and NOx emissions. A mechanism has been assembled in this work using well-validated plasma reactions of NH3 with O2 and N2, alongside plasma kinetics of air from the literature. Subsequently, the newly developed mechanism was used to investigate the plasma-assisted oxidation of NH3. In particular, the impact of the reduced electric field (E/N), equivalence ratio, pressure, pulse frequency, and energy density on the ignition delays and NOx emission were investigated. A Global Pathway-based Analysis algorithm for plasma-assisted systems (PGPA) is used to analyze the nanosecond pulsed nonequilibrium plasma-assisted combustion of NH3/air mixtures. Firstly, a faster ignition and lower production of NOx are observed in the case of plasma discharges compared to thermal energy deposition, owing to the enhanced production of OH radicals and the early reforming of NH3 to produce N2 and H2 with plasma, respectively. At lower reduced electric fields (E/N), PGPA analyses elucidated the significance of gas heating due to vibrational-translational cycles of NH3 and N2 on the increased reactivity of NH3/air mixtures as compared to ignition at a higher E/N. The fuel-lean mixture is observed to exhibit higher production of NOx than stoichiometric and fuel-rich mixtures, resulting from plasma chemistry involving oxygen radical and electronic excited states of N2. Higher rates of collisional quenching at higher pressures during the inter-pulse gaps are found to result in a lesser amount of electronically excited states of N2 and O2, resulting in lower production of air-bound NOx during the pulses. Complementing combustion enhancements, the study also considers the role of plasma-assisted systems in gas reforming, thereby imparting specific desired characteristics lacking in the original mixture. For instance, plasma-assisted reforming can be utilized to control emissions by reforming specific emission precursors or by improving the gas reactivity to promote clean combustion. Natural gas associated with oil wells and natural gas fields is a significant source of greenhouse gas emissions and airborne pollutants. Flaring/burning of the associated gas removes greenhouse gases like methane (CH4) and other hydrocarbons. Our study explores the possibility of enhancing the flaring of associated gas mixtures (C1 – C4 alkane mixture) using nanosecond pulsed non-equilibrium plasma discharges. A well-studied conventional combustion chemistry for small alkanes is coupled with the plasma kinetics of CH4, C2H6, C3H8, and N2, including electron-impact excitations, dissociations, and ionization reactions. The newly developed plasma-based flare gas chemistry is then utilized to investigate repetitively pulsed nonequilibrium plasma-assisted reforming and subsequent combustion of the flare gas mixture diluted with N2 at different conditions. The results indicate an enhanced production of H2 and C2H4 in the reformed gas mixture, owing to the electron-impact dissociations of alkanes and subsequent H-abstractions and recombination reactions, thereby resulting in a mixture of CH4, H2, C2H4, C2H2, and other unsaturated C3. The reformed mixture exhibits significantly high reactivity as exhibited by their increased flame speeds and shorter ignition delays. The reformed mixture is also observed to promote increased CH4 destruction levels and complete flaring, thereby reducing the emissions of CH4 and other hydrocarbons.
8
Starikovskiy, Andrey, Nickolay Aleksandrov, and Aleksandr Rakitin. "Plasma-assisted ignition and deflagration-to-detonation transition." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1960 (February 13, 2012): 740–73. http://dx.doi.org/10.1098/rsta.2011.0344.
Abstract:
Non-equilibrium plasma demonstrates great potential to control ultra-lean, ultra-fast, low-temperature flames and to become an extremely promising technology for a wide range of applications, including aviation gas turbine engines, piston engines, RAMjets, SCRAMjets and detonation initiation for pulsed detonation engines. The analysis of discharge processes shows that the discharge energy can be deposited into the desired internal degrees of freedom of molecules when varying the reduced electric field, E / n , at which the discharge is maintained. The amount of deposited energy is controlled by other discharge and gas parameters, including electric pulse duration, discharge current, gas number density, gas temperature, etc. As a rule, the dominant mechanism of the effect of non-equilibrium plasma on ignition and combustion is associated with the generation of active particles in the discharge plasma. For plasma-assisted ignition and combustion in mixtures containing air, the most promising active species are O atoms and, to a smaller extent, some other neutral atoms and radicals. These active particles are efficiently produced in high-voltage, nanosecond, pulse discharges owing to electron-impact dissociation of molecules and electron-impact excitation of N 2 electronic states, followed by collisional quenching of these states to dissociate the molecules. Mechanisms of deflagration-to-detonation transition (DDT) initiation by non-equilibrium plasma were analysed. For longitudinal discharges with a high power density in a plasma channel, two fast DDT mechanisms have been observed. When initiated by a spark or a transient discharge, the mixture ignited simultaneously over the volume of the discharge channel, producing a shock wave with a Mach number greater than 2 and a flame. A gradient mechanism of DDT similar to that proposed by Zeldovich has been observed experimentally under streamer initiation.
9
Barbosa, S., G. Pilla, D. A. Lacoste, P. Scouflaire, S. Ducruix, C. O. Laux, and D. Veynante. "Influence of nanosecond repetitively pulsed discharges on the stability of a swirled propane/air burner representative of an aeronautical combustor." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2048 (August 13, 2015): 20140335. http://dx.doi.org/10.1098/rsta.2014.0335.
Abstract:
This paper reports on an experimental study of the influence of a nanosecond repetitively pulsed spark discharge on the stability domain of a propane/air flame. This flame is produced in a lean premixed swirled combustor representative of an aeronautical combustion chamber. The lean extinction limits of the flame produced without and with plasma are determined and compared. It appears that only a low mean discharge power is necessary to increase the flame stability domain. Lastly, the effects of several parameters (pulse repetition frequency, global flowrate, electrode location) are studied.
10
Bak, Moon Soo, and Mark A. Cappelli. "Numerical studies of nitric oxide formation in nanosecond-pulsed discharge-stabilized flames of premixed methane/air." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2048 (August 13, 2015): 20140331. http://dx.doi.org/10.1098/rsta.2014.0331.
Abstract:
A simulation is developed to investigate the kinetics of nitric oxide (NO) formation in premixed methane/air combustion stabilized by nanosecond-pulsed discharges. The simulation consists of two connected parts. The first part calculates the kinetics within the discharge while considering both plasma/combustion reactions and species diffusion, advection and thermal conduction to the surrounding flow. The second part calculates the kinetics of the overall flow after mixing the discharge flow with the surrounding flow to account for the effect that the discharge has on the overall kinetics. The simulation reveals that the discharge produces a significant amount of atomic oxygen (O) as a result of the high discharge temperature and dissociative quenching of excited state nitrogen by molecular oxygen. This atomic oxygen subsequently produces hydroxyl (OH) radicals. The fractions of these O and OH then undergo Zel’dovich reactions and are found to contribute to as much as 73% of the total NO that is produced. The post-discharge simulation shows that the NO survives within the flow once produced.
11
Bulat, Pavel, Lev Grachev, Igor Esakov, and Vladimir Upyrev. "Stabilization of combustion front in supersonic flow using streamer’s discharge." MATEC Web of Conferences 209 (2018): 00017. http://dx.doi.org/10.1051/matecconf/201820900017.
Abstract:
Thermodynamic analysis shows that for flights with velocities exceeding six sound velocities, it is required to burn fuel not in a subsonic but in a supersonic flow. The aim of this work is to investigate the possibility of creating a stationary combustion front in a supersonic flow by igniting the mixture with an attached microwave discharge. Discharges are created on the resonator by means of a pulsed source of quasi-optical microwave radiation. This method of initiation is one or two orders of magnitude more economical than other known methods of plasma ignition and combustion stabilization. A numerical evaluation and comparison with experiment of the propagation velocity of a subcritical streamer discharge in a stationary medium and in a supersonic drifting flow are performed. Experiments have been conducted to ignite a flat flow of propane-air mixture, as well as ignition of the propane stream fed into the airflow, which simulates the operation of the fuel injector. In all cases, the experiments confirmed a steady fuel combustion, which was controlled by the temperature measurements with a thermocouple.
12
Pavan, Colin Armstrong, Santosh J. Shanbhogue, Drew Weibel, Felipe Gomez del Campo, Ahmed Ghoniem, and Carmen Guerra-Garcia. "Dynamic Response of Nanosecond Repetitively Pulsed Discharges to Combustion Dynamics: Regime Transitions Driven by Flame Oscillations." Plasma Sources Science and Technology, January 25, 2024. http://dx.doi.org/10.1088/1361-6595/ad227d.
Abstract:
Abstract When using nanosecond repetitively pulsed discharges to actuate on dynamic combustion instabilities, the environment the discharge is created in is unsteady and changing on the timescale of the combustion processes. As a result, individual discharge pulses are triggered in a background gas that evolves at the timescale of combustion dynamics, and pulse-to-pulse variations may be observed during the instability cycle. Prior work has studied nanosecond pulsed discharges in pin-to-ring configurations used to control instabilities in lean-operating swirl-stabilized combustors, and observed variable discharge behaviour. The focus of this work is on characterizing how the pulse-to-pulse discharge morphology, energy deposition, and actuation authority, evolve during the combustion instability cycle. This has important implications for designing effective plasma-assisted combustion control schemes. The discharge is observed in two distinct modes, a streamer corona and a nanosecond spark, with the occurrence of each regime directly linked to the phase of the combustor instability. Variation of pulse repetition frequency affects the total fraction of pulses in each mode, while variation of voltage affects the onset of the nanosecond spark mode. The transitions are described in terms of ratios of the relevant combustion and plasma timescales and the implications of this coupled interaction on the design of an effective control scheme is discussed.
13
Shanbhogue, Santosh J., Colin A. Pavan, Drew E. Weibel, Felipe Gomez del Campo, Carmen Guerra-Garcia, and Ahmed F. Ghoniem. "Control of Large-Amplitude Combustion Oscillations Using Nanosecond Repetitively Pulsed Plasmas." Journal of Propulsion and Power, February 1, 2023, 1–13. http://dx.doi.org/10.2514/1.b38883.
Abstract:
This paper details the use of nanosecond repetitively pulsed discharges to attenuate combustion instabilities in a 14 kW swirl-stabilized methane/air combustor. The combustor exhibits large-amplitude pressure oscillations ranging from 1 to 4% of the mean pressure during which the flame exhibits bulk motion in each instability cycle, upstream and downstream, as revealed by high-speed chemiluminescence. Control is accomplished with an electrode comprising a pin anode at the centerline of the combustor, allowing a nanosecond spark to be generated in a region spanning close to the flame base, through the shear layers of the swirling flow and ending at the metallic combustor wall. The discharges are generated using 20 kV, 9 kHz pulses; and they correspond to about 120 W of mean power. This results in a suppression of the peak amplitude of the pressure oscillations by a factor of two to four, and 5 dB in the rms value. Using phase-averaged visualizations of the flame with and without plasma, we detail the sequence of flame motion in the course of the instability. With the plasma active, this reveals significant interactions between the flame and the plasma during the suppression. Finally, we present a state-space model of the thermoacoustic system, and we demonstrate open-loop control of the instabilities.
14
Lacoste, D. A., J. P. Moeck, D. Durox, C. O. Laux, and T. Schuller. "Effect of Nanosecond Repetitively Pulsed Discharges on the Dynamics of a Swirl-Stabilized Lean Premixed Flame." Journal of Engineering for Gas Turbines and Power 135, no. 10 (August 30, 2013). http://dx.doi.org/10.1115/1.4024961.
Abstract:
The effects of nanosecond repetitively pulsed (NRP) plasma discharges on the dynamics of a swirl-stabilized lean premixed flame are experimentally investigated. Voltage pulses of 8 kV in amplitude and 10 ns in duration are applied at a repetition rate of 30 kHz. The average electric power deposited by the plasma is limited to 40 W, corresponding to less than 1% of the thermal power of 4 kW released by the flame. The investigation is carried out with a dedicated experimental setup that allows for studies of the flame dynamics with applied plasma discharges. A loudspeaker is used to acoustically perturb the flame and the discharges are generated between a central pin electrode and the rim of the injection tube. The velocity and CH* chemiluminescence signals are used to determine the flame transfer function, assuming that plasma discharges do not affect the correlation between the CH* emission and heat release rate fluctuations. Phase-locked images of the CH* emission show a strong influence of the NRP discharges on the flame response to acoustic perturbations, thus opening interesting perspectives for combustion control. An interpretation of the modifications observed in the transfer function of the flame is proposed by taking into account the thermal and chemical effects of the discharges. It is then demonstrated that by applying NRP discharges at unstable conditions, the oscillation amplitudes can be reduced by an order of magnitude, thus effectively stabilizing the system.
15
Shao, Xiao, Narjisse Kabbaj, Deanna A. Lacoste, and Hong G. Im. "A computational study of a laminar methane-air flame assisted by nanosecond repetitively pulsed discharges." Journal of Physics D: Applied Physics, February 9, 2024. http://dx.doi.org/10.1088/1361-6463/ad2836.
Abstract:
Abstract 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.
16
Aleksandrov, Nick L., Edward Bazelyan, Alexander Ponomarev, and Andrey Starikovskiy. "Kinetics of charged species in non-equilibrium plasma in water vapor- and hydrocarbon-containing gaseous mixtures." Journal of Physics D: Applied Physics, June 30, 2022. http://dx.doi.org/10.1088/1361-6463/ac7d7c.
Abstract:
Abstract In this review we describe the kinetics of non-equilibrium discharge plasma when the ion composition is dominated by water or hydrocarbon ions. Plasmas with water ions are formed in atmospheric discharges and discharges in the presence of liquid water or water vapor, including plasma applications for air purification, medicine and combustion. Reactions with hydrocarbon ions play an important role in interstellar chemistry, plasma enhanced chemical vapor deposition, synthetic diamond film deposition and plasma assisted combustion. The modeling of water ion chemistry and chemistry of hydrocarbon-containing plasmas requires large amount of data on the rates of ion formation and loss. This review provides the core database for the rate coefficients describing the kinetics of charged particles in plasmas with water and hydrocarbon ions as a function of temperature, pressure, and local electric field. Particular attention is given to cluster ions, which are important at not-too-low gas pressures, whereas the majority of studies of ion-molecule reactions have been performed at low pressures in the absence of cluster ions. To illustrate importance of the described processes, the development of streamer discharges in long humid air gaps are discussed and the influence of water ions on the streamer properties is demonstrated. In addition, the decay of non-equilibrium plasma with water and hydrocarbon ions is analyzed in combustible gaseous mixtures excited by a repetitively pulsed nanosecond discharge.
17
Guerra-Garcia, Carmen, and Colin A. Pavan. "The backward problem in plasma-assisted combustion: Experiments of nanosecond pulsed discharges driven by flames." Applications in Energy and Combustion Science, June 2023, 100155. http://dx.doi.org/10.1016/j.jaecs.2023.100155.
18
Blanchard, Victorien, Frédéric Roqué, Philippe Scouflaire, Christophe O. Laux, and Sébastien Ducruix. "Lean Flame Stabilization with Nanosecond Plasma Discharges in a Gas Turbine Model Combustor." Journal of Engineering for Gas Turbines and Power, December 12, 2023, 1–13. http://dx.doi.org/10.1115/1.4064265.
Abstract:
Abstract This paper presents an experimental study of lean flames stabilization with nanosecond repetitively pulsed discharges. The two-stage, swirled-stabilized, multipoint injector BIMER operates at atmospheric pressure with methane-air mixtures in the present study. It is representative in its design of a realistic lean premixed prevaporized injector of gas turbine engines operated at a lab-scale level. The lean blow-off extension with plasma is characterized. The combustion efficiency and the pollutant emissions are quantified near blow-off with and without plasma for 50-kW flames. We show that it is possible to stabilize lean flames down to an equivalence ratio of 0.3, with less than 5 ppm of NOX emitted, thanks to NRP discharges with an electric power that represents less than 0.25% of the flame thermal power. This study also clearly shows that it is necessary to account for the plasma system integration at the early stage of the combustor design to fully benefit from the plasma stabilizing effects on the flame.
19
Mehdi, Ghazanfar, Donato Fontanarosa, SARA BONUSO, and Maria Grazia De Giorgi. "Ignition thresholds and flame propagation of methane–air mixture: detailed kinetic study coupled with electrical measurements of the nanosecond repetitively pulsed plasma discharges." Journal of Physics D: Applied Physics, May 12, 2022. http://dx.doi.org/10.1088/1361-6463/ac6f2c.
Abstract:
Abstract A disk-ring nanosecond pulsed discharges plasma actuator was developed to be applied in a rectangular cross-section burner. The measured reduced electric field (EN), power dissipation and energy per pulse were used for validation of the plasma kinetic code ZDPlaskin. Then the effect of plasma discharges dynamics on methane/air flames, were numerically estimated. Firstly, plasma chemistry computations based on an extended kinetic mechanism of methane/air mixtures were performed by ZDPlasKin. Then, the results obtained by the ZDPlasKin in the form of kinetic effects (concentrations of O, OH, O3, CH, CH3 and H) and thermal effects (rise in temperature) were used in CHEMKIN to evaluate the combustion enhancement. The flame speed was improved by increasing both reduced electric field and repetition rates. Assuming EN = 200Td (as in experiments), and pulse repetition rate equal to 100Hz, the flame speed was increased of 26% in comparison with the case without the plasma actuation. Furthermore, at 10000 Hz, the flame speed was three times higher than at 100Hz. The ignition delay time greatly reduced from 1.2×10-3s (without plasma) up to 3.0×10-5s at 10000Hz repetition rate. The plasma assisted ignition n (PAI) permits ignition of the mixture at lower inlet temperature than in the case of self-ignition, meaning that ignition is possible in cold flow condition, with a possible application for the re-ignition problems at high altitude conditions. Finally, higher repetition rate leads to lower number of required pulses for the ignition of the CH4-air mixture and lower peak flame temperature.
20
Minesi, Nicolas, Victorien Blanchard, Erwan Pannier, Gabi Daniel Stancu, and Christophe O. Laux. "Plasma-assisted combustion with nanosecond discharges. Part I: discharge effects characterization in the burnt gases of a lean flame." Plasma Sources Science and Technology, March 11, 2022. http://dx.doi.org/10.1088/1361-6595/ac5cd4.
Abstract:
Abstract The prediction of a flame response to plasma assistance requires extensive knowledge of discharge-induced plasma kinetics. Detailed studies of nanosecond discharges are common in N2/O2 and fresh combustible mixtures but are still lacking in burnt gases. To fill this gap, we define a combustion reference test case and investigate the effects of Nanosecond Repetitively Pulsed (NRP) discharges placed in the recirculation zone of a lean (Φ = 0.8) CH4-air bluff-body stabilized flame at atmospheric pressure. In this zone, the plasma discharge is created in a mixture of burnt gases. Quantitative Optical Emission Spectroscopy (OES), coupled with measurements of electrical energy deposition, is performed to provide temporally (2 ns) and spatially (0.5 mm) resolved evolutions of the temperatures and concentrations of N2(B), N2(C), N2 +(B), OH(A), NH(A), and CN(B) in the discharge. At steady state, the 10-ns pulses deposit 1.8 mJ at a repetition frequency of 20 kHz. Spatially resolved temperature profiles are measured during the discharge along the interelectrode gap. The temperature variations are more pronounced near the electrodes than in the middle of the gap. On average, the gas temperature increases by approximately 550 K. The heat release corresponds to about 20% of the total deposited electric energy. The electron number density, measured by Stark broadening of Hα, increases up to about 1016 cm-3. These characteristics allow to classify the discharge as a non-equilibrium NRP spark, as opposed to the thermal NRP spark where the temperature can reach 40,000 K and the degree of ionization is close to 100%. These measurements will serve (i) as a reference for future studies in the Mini-PAC burner at the same conditions, (ii) to test discharge kinetic models, and (iii) to derive a simplified model of plasma-assisted combustion, which will be presented in companion paper.