Improvement of lean flame stability of inverse methane/air diffusion flame by using coaxial dielectric plasma discharge actuators

Giorgi, Maria Grazia De; Ficarella, Antonio; Sciolti, Aldebara; Pescini, Elisa; Campilongo, Stefano; Lecce, Giorgio Di

doi:10.1016/j.energy.2017.03.048

Cited by 37 publications

(12 citation statements)

References 31 publications

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“…Figure 16 shows the plasma composition that is calculated using the Saha equation (4) assuming LTE at the column zone versus the radial position for the three delays of 0, 50, and 100 s. During discharge lifetime, n WII decreases linearly towards the plasma periphery, while n WI increases at any delay. Figure 16 shows the plasma composition that is calculated using the Saha equation (4) assuming LTE at the column zone versus the radial position for the three delays of 0, 50, and 100 s. During discharge lifetime, n WII decreases linearly towards the plasma periphery, while n WI increases at any delay.…”

Section: Plasma Compositionmentioning

confidence: 99%

“…However, electrical discharges are used for hydrocarbon ignition in engines, [3,4] and stable ignition and growth of the initial flame kernel are practically important for higher performance of gasoline spark-ignition engines. For obvious safety issues, controlling the ignition and relighting efficiency of airplane engine, for instance, is then crucial.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of a spark discharge for dust cloud ignition

Sankhe

Bernard

Wartel

et al. 2018

Contributions to Plasma Physics

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Spark discharges are widely used to ignite flammable gases, liquids, or dust. For a better understanding of the interaction between the spark discharge and the ignited media (gas, liquid, or dust), it is necessary to measure some key parameters of the spark, especially the space-time variation of its temperature. Determination of temperature gradients would allow a more precise and realistic simulation of the ignition process. In fact, electrons and particles in the discharge zone get their energy with increasing temperature before interacting with particles of the media to ignite the flame. In this study, optical emission spectroscopy of the spark discharge between two tungsten electrodes was performed. Assuming excitation balance between the WI lines, a Boltzmann plot after an Abel inversion gives the excitation temperature and its space-time variation. For a 100-s time discharge, at 80-s delay, we measured 7,000 K at the centre of the column zone, 4,100 K at the centre of the cathode zone, and 3,600 K at the centre of the anode zone. Assuming a singly ionized tungsten plasma and excitation equilibrium, we used also the Saha-Boltzmann equation to calculate the plasma composition. The electron density at the column zone was about 3 × 10 17 cm −3 , which is two orders of magnitude higher than in the rest of the spark.

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Section: Plasma Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of a spark discharge for dust cloud ignition

Sankhe

Bernard

Wartel

et al. 2018

Contributions to Plasma Physics

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“…[35,36,37,38,39,40,41]. Among different nonthermal plasma processes such as dielectric barrier discharge (DBD), corona discharge, glow discharge and gliding arc, DBD plasma process is more stable and uniform having numerous potential industry applications [42,43,44]. Several efforts have been made by researchers in this direction for conversion of methane, ethanol and methanol with the help of the DBD plasma technique for the effective production of hydrogen gas.…”

Section: Introductionmentioning

confidence: 99%

Enhanced hydrogen generation efficiency of methanol using dielectric barrier discharge plasma methodology and conducting sea water as an electrode

Panda

Sahu

2020

Heliyon

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In this work, methanol decomposition method has been discussed for the production of hydrogen gas with the application of plasma. A simple dielectric barrier discharge (DBD) plasma reactor was designed for this purpose with two types of electrode. The DBD plasma reactor was experimented by substituting one of the metal electrodes with feebly conducting sea water which yielded better efficiency in producing hydrogen gas. Experimental parameters such as; discharge voltage and time were varied by maintaining a discharge gap of 1.5 mm and the plasma discharge characteristics were studied. Filamentary type micro-discharges were found to be formed which was observed as numerous streamer clusters in the current waveform. Gas chromatographic study confirmed the production of hydrogen gas with residence time around 3.6 min. Although, the concentration (%) of H 2 was high (98.1 %) and consistent with copper electrode assembly, the rate of formation and concentration was found to be the highest (98.7 %) for water electrode for specific discharge voltage. The energy efficiency was found to be 0.5 mol H 2 /kWh and 1.2 mol H 2 /kWh for metal (Cu) and water electrodes respectively. The electrode material significantly affects the plasma condition and hence the rate of hydrogen production. Compositional analysis of the water used as electrode showed a minimal change in the composition even after the completion of the experiment as compared to the untreated water. Methanol degradation study shows the presence of untreated methanol in the residue of the plasma reactor which has been confirmed from the absorption spectra.

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“…The author considers that the phenomenon was related to an increase in the flame propagation rate caused by plasma.The same AC-DBDPA and burner geometrical configuration were used by Xu et al [25], replacing propane with CH 4 , The above experimental results verified that it is the edge electric field that causes the acceleration of methane-air mixing process. De Giorgi explored the effect of plasma on the stability of CH 4 -air lean burn flame by intensified CCD imaging technology [26,27]. Based on the design of ceramic coaxial injector, the influence of plasma control on methane-air combustion flame with AC dielectric barrier discharge was studied by Zhou et al [28,29].…”

Section: Introductionmentioning

confidence: 99%

Characterization of the effects of a plasma injector driven by AC dielectric barrier discharge on ethylene-air diffusion flame structure

Zheng¹,

Nie

Zhou

et al. 2020

Open Physics

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AbstractA dielectric barrier discharge plasma controlled diffusion flame experimental system was built based on the designed coaxial swirling plasma injector. The air plasma was generated within the annulus gap of the injector by alternating current dielectric barrier discharge. The discharge characteristics and power of plasma injector under different actuation intensities and air flowrates were measured. Through the measurement techniques, such as schlieren imaging, broadband chemiluminescence image and CH* chemiluminescence, the effect and mechanism of plasma on ethylene-air normal diffusive jet and flame was explored. The results showed that a large number of filamentary discharge channels are formed in air plasma. The increase of air flowrates weakened the intensity of discharge to a certain extent. The induced jet generated by the plasma can short the laminar length of the ethylene-air jet, accelerate the transition of the flow jet, enhance the turbulence and the mixing of the fuel and the oxidizer. The higher the actuation intensity, the shorter distance of the cold jet transition zone, the higher the jet turbulence. Depending on the aerodynamic and kinetic effects, plasma can improve the stability of ethylene-air diffusive flame and reduce the lift height between the flame root and injector. The plasma can also expand the flammability limit of ethylene-air flame and make the flame ignited under some conditions that could not be. In addition, the CH* chemiluminescence shows that, in a certain range of discharge voltage, the heat release distribution can be changed on both sides of the flame, and its representative length are generally reduced as the voltage rises. On the contrary, the overtop voltage could lead to a decrease of flame heat release.

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Improvement of lean flame stability of inverse methane/air diffusion flame by using coaxial dielectric plasma discharge actuators

Cited by 37 publications

References 31 publications

Characterization of a spark discharge for dust cloud ignition

Characterization of a spark discharge for dust cloud ignition

Enhanced hydrogen generation efficiency of methanol using dielectric barrier discharge plasma methodology and conducting sea water as an electrode

Characterization of the effects of a plasma injector driven by AC dielectric barrier discharge on ethylene-air diffusion flame structure

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