The effects of hydrodynamic stretch on the flame propagation enhancement of ethylene by addition of ozone

Pinchak, Matthew D.; Ombrello, Timothy; Carter, Campbell; Gutmark, Ephraim; Katta, Viswanath R.

doi:10.1098/rsta.2014.0339

Cited by 15 publications

(3 citation statements)

References 34 publications

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“…However, at pressures below 0.6 atm, Gao et al found that the flame speed was enhanced by O 3 . Other studies , also reached similar conclusions under reduced pressures.…”

Section: Introductionsupporting

confidence: 76%

“…Nonetheless, the understanding of how ozonolysis affects flame propagation is still incomplete. Reducing the pressure ,, simply redirects the O 3 consumption from ozonolysis reactions to the O 3 + H = O 2 + OH pathway. Several questions remain, including how decreased residence times alter ozonolysis-assisted flame propagation at atmospheric pressure and whether one-dimensional simulations are capable of accurately predicting experimental measurements when ozonolysis reactions are responsible for the majority of O 3 consumption.…”

Section: Introductionmentioning

confidence: 99%

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Burner Platform for the Investigation of Ozonolysis-Assisted Flame Speeds

Reuter

Ombrello

2021

Energy Fuels

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This study presents a new coinjected reactor-assisted Bunsen (CRAB) burner for the experimental investigation of ozonolysis-assisted flame speeds at atmospheric pressure and room temperature. The CRAB burner’s capacity to modify the residence time of the ethylene/air/ozone mixture prior to the flame front is crucial for controlling the extent of ozonolysis reactions and ozone consumption. The experimental measurements reveal that, with ozone addition and the subsequent ozonolysis reactions, longer residence times result in higher pre-flame temperatures, which lead to an increase in the flame speed. The flame speed enhancement by ozone is the largest for high ozone concentrations and off-stoichiometric mixtures. One-dimensional numerical simulations employing detailed chemical kinetic models are able to capture the enhancement of the flame speed quite accurately through the use of a plug flow reactor in combination with a freely-propagating laminar flame. However, the absolute flame speeds predicted by the simulations are not always in agreement with the experimental measurements, particularly for mixtures with lean equivalence ratios. Further analysis of the results shows that the adiabaticity of the upstream flow reactor has an enormous influence on the flame speed enhancement by ozone; in fact, the temperature rise is the dominant mechanism for the increase in the flame speed. The kinetic effects of ozonolysis reactions, which are much less impactful that the thermal effects, can lead to a decrease in the flame speed at extended residence times due to radical recombination.

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“…However, at pressures below 0.6 atm, Gao et al found that the flame speed was enhanced by O 3 . Other studies , also reached similar conclusions under reduced pressures.…”

Section: Introductionsupporting

confidence: 76%

Section: Introductionmentioning

confidence: 99%

Burner Platform for the Investigation of Ozonolysis-Assisted Flame Speeds

Reuter

Ombrello

2021

Energy Fuels

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“…On the application side, the enhancement of combustion by ozone is of interest, for example, in studies of the increase in burning velocities of methane/air flames and similar systems. − …”

Section: Introductionmentioning

confidence: 99%

H-Atom Abstraction Reactions by Ground-State Ozone from Saturated Oxygenates

Würmel

Simmie

2017

J. Phys. Chem. A

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Theoretical insights into H-abstraction by ozone from saturated species have been virtually nonexistent, in sharp contrast to the situation for reactions with unsaturated species. Our computed rate constants for reactions with tetrahydrofuran and its methyl derivatives, obtained at various levels of theory, show that abstraction occurs primarily at the carbons situated beside the heterocyclic oxygen, with least likely reaction from the methyl groups. All of the methods tested are in broad relative agreement with this conclusion and with recent experiments although they do differ widely in terms of their absolute values. Abstraction leads variously to the formation of hydrotrioxides, ROOOH, or more directly to R-OH + O(Δ). To understand some of the observed behaviors, dimethyl and diethyl acyclic ethers, methyl and ethyl hydroperoxides, and the alcohols methanol and ethanol were also included in this study. For the simplest system, CHOH + O → HC═O + HO, an all-electron scalar relativistic CCSD(T)/CBS approach yields a barrier height that differs by >5 kJ mol when an additional multireference treatment up to CCSDT(Q) is considered.

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