Spark ignited hydrogen/air mixtures: two dimensional detailed modeling and laser based diagnostics

Thiele, M.; Warnatz, Jürgen; Dreizler, Andreas; Lindenmaier, S.; Schießl, Robert; Maas, Ulrich; Grant, A.; Ewart, Paul

doi:10.1016/s0010-2180(01)00333-9

Cited by 60 publications

(33 citation statements)

References 24 publications

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“…7. In agreement with experimental observations (Thiele et al, 2002), the predicted transient OH concentration peaks at around an order of magnitude higher than in the steady diffusion flame and then it decays while the temperature falls. The shape of the OH profile reflects that of the temperature, rather than the heat release.…”

Section: Ignition Evolutionsupporting

confidence: 88%

“…Alternative sparks include Laser Induced Spark Ignition that delivers a measurable quantity of energy to the fluid at the focus of the laser beam over a relatively short period of time, 5-500 ns (Phuoc, 2002). However, all types of sparks include complicated flow patterns, ionization, and shock waves (Kono et al, 1984 andBradley et al, 2004) and are hence not easy to represent numerically, although the discharge phase following breakdown has been successfully modeled (Thiele et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Numerical Investigation of Forced Ignition in Laminar Counterflow Non-Premixed Methane-Air Flames

Richardson

Mastorakos

2007

Combustion Science and Technology

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Simulations of forced ignition of non-premixed laminar counterflow flames are used to study the effect of strain rate on ignition success. A one dimensional calculation is performed, using detailed methane chemical kinetics and treating the spark as an instantaneous heat release in an inert mixing layer. Ignition success depends on the mixture composition at the spark location, resulting in lean and rich ignitability limits for a given spark that can be different from the fuel's static flammability limits. The difference is attributed to the finite spark width and the diffusion of heat from the spark to the flammable mixture. Ignition is prohibited by excessive strain rates, in some cases at levels well below the extinction value. The structure of the evolving flame is examined in terms of temperature, heat release rate and species mass fraction distributions. In the case of successful ignition, the high temperature reached due to the spark energy deposition causes local auto-ignition and subsequently, intense burning rapidly consumes the premixed reactants in the mixing layer and a non-premixed flame survives. In the case of unsuccessful ignition, despite the auto-ignition achieved in the sparked region, the strain rate is sufficiently high or the composition is sufficiently far away from the nominally flammable mixture for the heat and radicals to diffuse without resulting in a flame at long times from the spark event.

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Section: Ignition Evolutionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Forced Ignition in Laminar Counterflow Non-Premixed Methane-Air Flames

Richardson

Mastorakos

2007

Combustion Science and Technology

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“…This error is corrected by returning to the work of Westbrook 23 and adopting the corresponding reactions. Thiele et al 24 used a time-dependent two-dimensional model to simulate the spark-ignition in a quiescent hydrogen-air mixture described by a detailed kinetics. The reaction mechanism consists of N = 9 species and J = 38 irreversible reactions, adopted from the work of Warnatz et al 25 Although the grid discretization in this study is not mentioned, the predicted required length scale, 7.56 × 10 −4 cm, to fully resolve such a system was beyond the existing computational capabilities.…”

Section: Ivd Comparison With Previously Published Resultsmentioning

confidence: 99%

Verified Computations of Laminar Premixed Flames

Al-Khateeb

Powers

Paolucci

2007

45th AIAA Aerospace Sciences Meeting and Exhibit

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The required spatial discretization to capture all detailed continuum physics in the reaction zone for one-dimensional steady laminar premixed hydrogen-air flames described by detailed kinetics and multi-component transport is accurately estimated a priori by a simple mean free path calculation. To verify this, a robust method has been developed to rigorously calculate the finest length scale a posteriori. The method reveals that the finest length scale is at the micron-level. This result is consistent with an estimate from the underlying molecular collision theory, and orders of magnitude smaller than the discretization scales employed in nearly all multi-dimensional and/or unsteady laminar premixed flame simulations in the literature.

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“…The localised ignition and subsequent flame propagation in homogeneous mixtures have been studied from analytical [1][2][3][4], experimental [5][6][7][8][9][10] and numerical [10][11][12][13][14][15][16][17] viewpoints by several authors. Interested readers are referred to Ref.…”

Section: Introductionmentioning

confidence: 99%

“…The adverse effects of turbulent velocity fluctuation on ignition and early stages of flame propagation in homogeneous mixtures were reported and analysed from various viewpoints in Refs. [5][6][7][8][9][10][11][12][13][14][15][16][17]. In a recent analysis Wandel [23] demonstrated that the absence of a substantial region containing hot products with small values of scalar dissipation rate could be detrimental to the ignition of partiallypremixed gases resulting from droplet-laden mixtures, and such an extinction predictor can also be relevant to the ignition of gaseous homogeneous mixtures.…”

Section: Introductionmentioning

confidence: 99%

Effects of Energy Deposition Characteristics on Localised Forced Ignition of Homogeneous Mixtures

Patel

Chakraborty

2015

International Journal of Spray and Combustion Dynamics

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The effects of the characteristic width of the energy deposition profile and the duration of energy deposition by the ignitor on localised forced ignition of stoichiometric and fuel-lean homogeneous mixtures have been analysed using simplified chemistry three-dimensional compressible Direct Numerical Simulation (DNS) for different values of root-mean-square turbulent velocity fluctuation. The localised forced ignition is modelled using a source term in the energy transport equation, which deposits energy in a Gaussian manner from the centre of the ignitor over a stipulated period of time. It has been shown that the width of ignition energy deposition and the duration over which ignition energy is deposited have significant influences on the success of ignition and subsequent flame propagation. An increase in the width of ignition energy deposition (duration of energy deposition) for a given amount of ignition energy has been found to have a detrimental effect on the ignition event, which may ultimately lead to misfire. Moreover, an increase in uЈ gives rise to augmented heat transfer rate from the hot gas kernel, which in turn leads to a reduction in the extent of overall burning for both stoichiometric and fuel-lean homogeneous mixtures but the detrimental effects of high values of uЈ on localised ignition are particularly prevalent for fuel-lean mixtures.

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Spark ignited hydrogen/air mixtures: two dimensional detailed modeling and laser based diagnostics

Cited by 60 publications

References 24 publications

Numerical Investigation of Forced Ignition in Laminar Counterflow Non-Premixed Methane-Air Flames

Numerical Investigation of Forced Ignition in Laminar Counterflow Non-Premixed Methane-Air Flames

Verified Computations of Laminar Premixed Flames

Effects of Energy Deposition Characteristics on Localised Forced Ignition of Homogeneous Mixtures

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