The effects of applying electric fields on the mass spectrometric sampling of positive and negative ions from a flame at atmospheric pressure

Hayhurst, A.N.; Goodings, John M.; Taylor, Simon

doi:10.1016/j.combustflame.2014.06.012

Cited by 12 publications

(8 citation statements)

References 60 publications

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“…In closing, it is worth noting that it is more difficult to measure accurately the concentration of negative ions in flames than for positive ions [55]. Thus, kinetic models for negative ions are more rudimentary and important pathways may be missing and rate parameters inaccurate.…”

Section: Setup Of the Uq Problemmentioning

confidence: 99%

Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon

Kim

Rizzi

Cheng

et al. 2015

Combustion and Flame

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Section: Setup Of the Uq Problemmentioning

confidence: 99%

Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon

Kim

Rizzi

Cheng

et al. 2015

Combustion and Flame

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“…Although a flame contains charged species such as free electrons, positive and negative ions together with charged soot particles, it is weak plasma and electrically neutral as an integral whole [16]. The induced signal from the isolated electrode placed around the flame is entirely due to electrostatic induction from the charged species and thus its amplitude is very small and negligible.…”

Section: A Sensing Principlementioning

confidence: 99%

“…Although such ion-current sensors provide localised information about a flame, the external voltage applied to the flame can affect the combustion rate, and the shape, stability of the flame. Mass spectrometers were employed to identify the positive and negative ions, particularly in hydrocarbon flames [15][16][17]. Guo et al [15] collected the total flux of cations that collides with a conductive plate perpendicular to the flame axis and detected a saturation current to measure the concentration of positive ions in a flat flame.…”

Section: Introductionmentioning

confidence: 99%

“…Guo et al [15] collected the total flux of cations that collides with a conductive plate perpendicular to the flame axis and detected a saturation current to measure the concentration of positive ions in a flat flame. Hayhurst et al [16] investigated the effect of applied electric fields on the mass spectrometric sampling of positive and negative ions from a flat flame. In these cases, the flame is generally doped with an appropriate additive (the easily-ionizable alkali metal) to allow the degree of ionization to be enhanced above the natural ionization level.…”

Section: Introductionmentioning

confidence: 99%

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Measurement of Charge Density in Methane Fired Diffusion and Premixed Flames Using Electrostatic Probes

Yan

2021

IEEE Sensors J.

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The charge density in a flame contains important information about the combustion processes that is difficult to obtain due to fast, complex, and highly exothermic reactions. This paper presents a study of using electrostatic probes to measure the charge density in methane fired diffusion and premixed flames. The sensing principle, practical design, and performance assessment of the electrostatic probe are presented.Comparative experimental studies with a reference ion-current sensor carried out on a combustion test rig indicate that the fluctuation of the signal from the electrostatic probe arises from the variation in the charge density in a flame. A dimensionless index, combining the average of local peak values in the electrostatic signal with the flame oscillation frequency, is adopted as an indicator of the charge density. Experimental results demonstrate that the charge density in a methane diffusion flame has an increasing trend with the fuel flowrate varying from 0.80 L/min to 1.20 L/min. The charge density in a methane-air premixed flame yields a decreasing trend with the equivalence ratio ranging from 0.54 to 0.75, then increases and reaches a local peak at the equivalence ratio of 1.03, and continues to increase when the equivalence ratio varies from 1.03 to 3.50. The charge density in the inner cone is higher than that in the outer cone for diffusion and premixed flames. The results obtained suggest that the developed electrostatic probe and the index can be used to indicate the charge density in diffusion and premixed flames.

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“…4 for the different anodes. The data are plotted as a function of voltage as opposed to a global electric field defined as the voltage divided by the electrode separation because the actual electric field within the flame is not constant and will vary depending on the charged particle density and thickness of the burner plasma sheaths [22,25,28,29]. The plot shows that current has the same profile for a given location for both small and medium anode rings.…”

Section: A Electrical Characteristicsmentioning

confidence: 99%

Electric Field Modified Bunsen Flame with Variable Anode Placement

Salvador

2017

Journal of Thermophysics and Heat Transfer

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A methane-air Bunsen flame was tested under dc electric field forcing with different ring anode sizes and locations. The anodes were placed within the flame to far outside the flame, both axially and radially. The focus of the work is to understand the limit of electrode placement and its effect on the flame under a dc field. A stoichiometric flame with voltages up to 9.1 kV was tested. The electrical current and flame height were measured as a function of the bias voltage and anode location. Plasma density measurements of the unmodified flame at various axial locations were used to corroborate that anode placement at regions of high electron density caused the largest reductions in flame height. The results showed the anodes closest to the burner at 35 mm caused the largest reduction (24%) in flame height. The effect of the electric field on flame height decreased as the anode moved farther downstream of the flame or radially outward. For the same voltage, larger currents were also observed for anodes close to the burner, whereas anodes placed far outside of the flame had minimal effects on current and, consequently, on the flame height. These differences are due to the variable electron density at the anode, which limits the net current collected and the strength of the field.

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The effects of applying electric fields on the mass spectrometric sampling of positive and negative ions from a flame at atmospheric pressure

Cited by 12 publications

References 60 publications

Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon

Uncertainty quantification of ion chemistry in lean and stoichiometric homogenous mixtures of methane, oxygen, and argon

Measurement of Charge Density in Methane Fired Diffusion and Premixed Flames Using Electrostatic Probes

Electric Field Modified Bunsen Flame with Variable Anode Placement

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