Flame propagation across an obstacle: OH-PLIF and 2-D simulations with detailed chemistry

Boeck, Lorenz R.; Lapointe, Simon; Melguizo-Gavilanes, J.; Ciccarelli, G.

doi:10.1016/j.proci.2016.06.097

Cited by 33 publications

(13 citation statements)

References 20 publications

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“…It is ignited at the left closed end using a semi-spherical 5 mm radius hot kernel. This initialization procedure was employed in other gas explosion studies ranging from venting deflagrations [12,14] to DDT [1,13] . Among all the equivalence ratios considered in the experiments, the case corresponding to stoichiometric hydrogen/air and showing DDT was selected.…”

Section: Numerical Setupmentioning

confidence: 99%

“…Gas explosions have been studied experimentally [1,5] , theoretically [4,[6][7][8][9][10][11] and numerically [1,[12][13][14] . They occur when a reactive mixture is subjected to an external source of energy from which a combustion wave emerges.…”

Section: Introductionmentioning

confidence: 99%

“…Deflagrations are intrinsically unstable and tend to accelerate continuously after ignition [16] . This Flame Acceleration (FA) process is well understood thanks to extensive experimental (summarized in the Ciccarelli and Dorofeev review paper [5] ), theoretical [6][7][8] and numerical [12,13] works and depends on the degree of confinement and obstruction encountered by the flame during its propagation. FA can either result in fast deflagrations or create the appropriate conditions for the Deflagration-to-Detonation Transition (DDT).…”

Section: Introductionmentioning

confidence: 99%

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Influence of kinetics on DDT simulations

Dounia

Vermorel

Misdariis

et al. 2019

Combustion and Flame

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Deflagration to Detonation Transition (DDT) is an intricate problem that has been tackled numerically, until recently, using single-step chemical schemes. These studies (summarized in Oran and Gamezo, 2007) [1] showed that DDT is triggered when a gradient of reactivity forms inside a pocket of unreacted material. However, recent numerical simulations of hydrogen/air explosions using detailed reaction mechanisms (Liberman et al., 2010; Ivanov et al., 2011) [2,3] showed that detonation waves can emerge from the flame brush, unlike what was usually seen in the single-step simulations. The present work focuses on chemistry modeling and its impact on DDT. Using the idealized Hot Spot (HS) problem with constant temperature gradient, this study shows that, in the case of hydrogen/air mixtures, the multi-step chemical description is far more restrictive than the single-step model when it comes to the necessary conditions for a hot spot to lead to detonation. A gas explosion scenario in a confined and obstructed channel filled with an hydrogen/air mixture is then considered. In accordance with the HS analysis, the Zeldovich's (1970) mechanism [4] is responsible for the detonation initiation in the single-step case, whereas another process, directly involving the deflagration front, initiated DDT in the complex chemistry case. In the latter, a shock focusing event leads to DDT in the flame brush through Pressure Pulse (PP) amplification.

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Section: Numerical Setupmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of kinetics on DDT simulations

Dounia

Vermorel

Misdariis

et al. 2019

Combustion and Flame

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“…When a gas explosion occurs in the mine, all kinds of electromechanical devices become obstacles in the roadway, which intensies the ame propagation; Boeck, 3 Karanam,4 Na'inna 5 and Hall et al 6 investigated the effects of the blockage ratio, position, number and shape of obstacles on ame propagation velocity, overpressure and induced ame turbulence via experimental tests and numerical simulations. The structure of a roadway is complex.…”

Section: Introductionmentioning

confidence: 99%

Study on noise-vibration coupling characteristics of premixed methane–air flame propagation in a tube with an acoustic absorption material

et al. 2019

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“…Minimal induction length predictions when employing detailed chemistry models along with accurate kinetic-transport models were found to be 2-3 orders of magnitude greater than those predicted employing single-step global chemistry models. Consequently, several recent studies have employed detailed chemistry models to simulate detonation scenarios in spite of the high computational cost [9,[11][12][13][14]. Using accurate kinetic-transport models in conjunction with detailed chemistry becomes even more important in detonation scenarios involving hydrogen, due to the differential diffusivities of hydrogen and oxidizer molecules resulting in non-unity Lewis numbers [14].…”

Section: Introductionmentioning

confidence: 99%

Impact of Radiative Losses on Flame Acceleration and Deflagration to Detonation Transition of Lean Hydrogen-Air Mixtures in a Macro-Channel with Obstacles

Krishnamoorthy

Mulenga

2018

Fluids

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While there has been some recognition regarding the impact of thermal boundary conditions (adiabatic versus isothermal) on premixed flame propagation mechanisms in micro-channels (hydraulic diameters <10 mm), their impact in macro-channels has often been overlooked due to small surface-area-to-volume ratios of the propagating combustion wave. Further, the impact of radiative losses has also been neglected due to its anticipated insignificance based on scaling analysis and the high computational cost associated with resolving it’s spatial, temporal, directional, and wavelength dependencies. However, when channel conditions promote flame acceleration and deflagration-to-detonation transitions (DDT), large pressures are encountered in the vicinity of the combustion wave, thereby increasing the magnitude of radiative losses which in turn can impact the strength and velocity of the combustion wave. This is demonstrated for the first time through simulations of lean (equivalence ratio: 0.5) hydrogen-air mixtures in a macro-channel (hydraulic diameter: 174 mm) with obstacles (Blockage ratio: 0.51). By employing Planck mean absorption coefficients in conjunction with the P-1 radiation model, radiative losses are shown to affect the run-up distances to DDT in a long channel (length: 11.878 m). As anticipated, the differences in run-up distances resulting from radiative losses only increased with system pressure.

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Flame propagation across an obstacle: OH-PLIF and 2-D simulations with detailed chemistry

Cited by 33 publications

References 20 publications

Influence of kinetics on DDT simulations

Influence of kinetics on DDT simulations

Study on noise-vibration coupling characteristics of premixed methane–air flame propagation in a tube with an acoustic absorption material

Impact of Radiative Losses on Flame Acceleration and Deflagration to Detonation Transition of Lean Hydrogen-Air Mixtures in a Macro-Channel with Obstacles

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