Investigation of NO production and flame structure in plasma enhanced premixed combustion

Kim, Woo-Kyung; Do, Hyungrok; Mungal, M. G.; Cappelli, Mark A.

doi:10.1016/j.proci.2006.07.107

Cited by 58 publications

(31 citation statements)

References 10 publications

(9 reference statements)

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“…The trend seen indicates that the NO concentration first rises and then falls slightly with increasing equivalence ratio, from values of 0-0.49. We believe that this trend reflects an increase and subsequent decrease in temperature, attributed to the concomitant behavior in discharge coupling and its dependence on methane mole fraction [16]. At equivalence ratios just beyond 0.49, we see an abrupt reduction (40%) in NO mole fraction.…”

Section: Characteristics Of the Preflamementioning

confidence: 66%

“…The study described here is focused on our continued examination of the use of nonequilibrium plasmas in extending the LFL of premixed hydrocarbon-air fuel combustion [8,16,17]. Here, we experimentally identify the presence of a stream of long-range, stable intermediate species (which we shall refer to as a ''preflame") generated by a nanosecond pulsed plasma discharge (NPPD), which persist past the decay of the short lived radicals and eventually assists in extending the LFL.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The role of in situ reforming in plasma enhanced ultra lean premixed methane/air flames

Kim

Mungal

Cappelli

2010

Combustion and Flame

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141

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Section: Characteristics Of the Preflamementioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

The role of in situ reforming in plasma enhanced ultra lean premixed methane/air flames

Kim

Mungal

Cappelli

2010

Combustion and Flame

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141

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“…In addition to direct electron-induced reactions, it is also possible that electronically excited N 2 can channel energy to other species, further enhancing the radical pool. A preliminary reaction path analysis [28] supports the conjecture that energy transfer between excited N 2 and atomic hygrogen (H), atomic oxygen (O), molecular oxygen (O 2 ), methyl radical (CH 3 ), and hydroperoxyl radical (HO 2 ) may lead to increased OH levels, which promotes flame stability. However, further studies are needed to develop a quantitative understanding on the balance between energy coupling and kinetics that leads to an optimum stabilization where the local mixing fraction Z is 65% of the stoichiometric value Z st .…”

Section: B Optimal Discharge Placementmentioning

confidence: 82%

Plasma-Discharge Stabilization of Jet Diffusion Flames

Kim

Mungal

et al. 2006

IEEE Trans. Plasma Sci.

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Abstract-The authors examine three different types of plasma discharges in their ability to stabilize a lifted jet diffusion flame in coflow. The three discharges include a single-electrode corona discharge, an asymmetric dielectric-barrier discharge (DBD), and a repetitive ultrashort-pulsed discharge. The degree of nonequilibrium of this pulsed discharge is found to be higher than that for the DBD. Furthermore, this pulsed discharge causes the most significant improvement in the flame stability. The optimal placement of the discharge electrodes is investigated, and it is found that there is a close relation between this placement and the emission spectra, suggesting use of the emission spectra as a possible indicator of fuel/air mixture fraction. The optimal placement is mapped into mixture-fraction space by use of a fully premixed flame experiment of known mixture fraction. The result shows that the mixture fraction, which corresponds to the optimal placement, is much leaner than that of a conventional lifted jet flame.

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“…Recent experimental studies [13][14][15] have reported that the level of NO that is formed in the plasma can be higher than that associated with the combustion process itself. They suggested that this is because molecular oxygen dissociates into atomic oxygen within the plasma and that these O radicals subsequently participate in NO formation through the Zel'dovich mechanism [16], described by the following two reactions: The reaction of atomic nitrogen with the hydroxyl radical…”

Section: Introductionmentioning

confidence: 99%

Numerical studies of nitric oxide formation in nanosecond-pulsed discharge-stabilized flames of premixed methane/air

Bak

Cappelli

2015

Phil. Trans. R. Soc. A.

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One contribution of 14 to a theme issue 'Physics and chemistry of plasma-assisted combustion' . A simulation is developed to investigate the kinetics of nitric oxide (NO) formation in premixed methane/air combustion stabilized by nanosecondpulsed 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.

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Investigation of NO production and flame structure in plasma enhanced premixed combustion

Cited by 58 publications

References 10 publications

The role of in situ reforming in plasma enhanced ultra lean premixed methane/air flames

The role of in situ reforming in plasma enhanced ultra lean premixed methane/air flames

Plasma-Discharge Stabilization of Jet Diffusion Flames

Numerical studies of nitric oxide formation in nanosecond-pulsed discharge-stabilized flames of premixed methane/air

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