Dynamics of laminar ethylene lifted flame with ozone addition

Bin, Wu; Hastings, Mitchell; Sun, Wenting; Ombrello, Timothy; Carter, Campbell

doi:10.1016/j.proci.2020.09.027

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…Interestingly, however, the blowoff velocity (defined in this instance as the velocity at the start of the flow reactor section) is decreases with O 3 addition. This may possibly be related to a recent study 35 in which the blowout velocity of lifted ethylene jet flames was observed to decrease with O 3 addition for t res larger than ∼20 ms.…”

Section: Modelingsupporting

confidence: 62%

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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Section: Modelingsupporting

confidence: 62%

Burner Platform for the Investigation of Ozonolysis-Assisted Flame Speeds

Reuter

Ombrello

2021

Energy Fuels

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“…Ozone is a strong oxidizer and can be produced at high pressures, which is suitable for most practical combustion facilities . The fundamental research for ozone enhancement on combustion has been conducted for various fuels, such as CH 4 , , C 2 H 4 , , dimethyl ether (DME), ethanol, n -heptane, methyl crotonate, and methyl hexanoate . The effect of ozone addition on ammonia combustion has only been studied regarding laminar burning velocity (LBV) by Chen et al The enhancement of the LBV of the NH 3 /O 2 /N 2 mixture by O 3 addition is more significant in fuel-lean conditions than in fuel-rich and stoichiometric conditions.…”

Section: Introductionmentioning

confidence: 99%

Exploring the Effect of Different Reactivity Promoters on the Oxidation of Ammonia in a Jet-Stirred Reactor

Shu

et al. 2023

J. Phys. Chem. A

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The low reactivity of ammonia (NH 3 ) is the main barrier to applying neat NH 3 as fuel in technical applications, such as internal combustion engines and gas turbines. Introducing combustion promoters as additives in NH 3 -based fuel can be a feasible solution. In this work, the oxidation of ammonia by adding different reactivity promoters, i.e., hydrogen (H 2 ), methane (CH 4 ), and methanol (CH 3 OH), was investigated in a jet-stirred reactor (JSR) at temperatures between 700 and 1200 K and at a pressure of 1 bar. The effect of ozone (O 3 ) was also studied, starting from an extremely low temperature (450 K). Species mole fraction profiles as a function of the temperature were measured by molecular-beam mass spectrometry (MBMS). With the help of the promoters, NH 3 consumption can be triggered at lower temperatures than in the neat NH 3 case. CH 3 OH has the most prominent effect on enhancing the reactivity, followed by H 2 and CH 4 . Furthermore, two-stage NH 3 consumption was observed in NH 3 /CH 3 OH blends, whereas no such phenomenon was found by adding H 2 or CH 4 . The mechanism constructed in this work can reasonably reproduce the promoting effect of the additives on NH 3 oxidation. The cyanide chemistry is validated by the measurement of HCN and HNCO. The reaction CH 2 O + NH 2 ⇄ HCO + NH 3 is responsible for the underestimation of CH 2 O in NH 3 /CH 4 fuel blends. The discrepancies observed in the modeling of NH 3 fuel blends are mainly due to the deviations in the neat NH 3 case. The total rate coefficient and the branching ratio of NH 2 + HO 2 are still controversial. The high branching fraction of the chain-propagating channel NH 2 + HO 2 ⇄ H 2 NO + OH improves the model performance under lowpressure JSR conditions for neat NH 3 but overestimates the reactivity for NH 3 fuel blends. Based on this mechanism, the reaction pathway and rate of production analyses were conducted. The HONO-related reaction routine was found to be activated uniquely by adding CH 3 OH, which enhances the reactivity most significantly. It was observed from the experiment that adding ozone to the oxidant can effectively initiate NH 3 consumption at temperatures below 450 K but unexpectedly inhibit the NH 3 consumption at temperatures higher than 900 K. The preliminary mechanism reveals that adding the elementary reactions between NH 3 -related species and O 3 is effective for improving the model performance, but their rate coefficients have to be refined.

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“…At the same time, the discharge will decompose some large fuel molecules into small fuel fragments, and the electric field between the electrodes drives the fluid to flow [14]; thus, the ion wind formed between the two electrodes also accelerates the mixing of fuel and oxidant [15], which all contribute to the progress of chemical reactions and enhance the ignition and burning processes. Wu et al [16] studied an ethylene coaxial jet laminar flame. In the study, O 3 was generated by plasma discharge, and the spatial distribution of CH 2 O in the flame was investigated by PLIF.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Spectral Characteristics of Gliding Arc Plasma Assisted Ammonia Lean Combustion

et al. 2022

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Ammonia as a non-carbon fuel is expected to play an important role in the future, but it is difficult to be effectively utilized at this stage due to its flame retardancy and other characteristics. Therefore, we propose to use gliding arc plasma combined with a swirl burner to enhance the combustion performance of ammonia. The electrical characteristics, electron density, gas rotational temperature and the distribution of key active species in the burner were studied via optical emission spectroscopy (OES). With the increase of equivalence ratio (EQR), the width of the Hα line decreases significantly, indicating that the electron density shows a downward trend, even as the gas rotational temperature shows an upward trend. When the equivalence ratio was 0.5, the gas rotational temperature increases by about 320 K compared with the pure air condition. During pure air discharge, there will still be obvious NO emission due to the plasma reaction, but with the addition of NH3, the NO content in the emission is significantly reduced. The light intensity of O atoms in the burner gradually decreases with the increase of the equivalence ratio, the light intensity of H atoms increases first and then decreases, and the light intensity of NH shows an upward trend. The reason may be that the plasma discharge effectively strengthens NH3(E)->NH2+H, NH2+H->NH+H2 and other reactions promote the initial reaction step of NH3 which thus effectively strengthens the NH3 combustion.

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Dynamics of laminar ethylene lifted flame with ozone addition

Cited by 4 publications

References 25 publications

Burner Platform for the Investigation of Ozonolysis-Assisted Flame Speeds

Burner Platform for the Investigation of Ozonolysis-Assisted Flame Speeds

Exploring the Effect of Different Reactivity Promoters on the Oxidation of Ammonia in a Jet-Stirred Reactor

Investigation on Spectral Characteristics of Gliding Arc Plasma Assisted Ammonia Lean Combustion

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