Experimental and numerical investigation of an ultra-low NO x methane reactor

Helou, Ingrid El; Foale, Jenna M.; Giusti, Andrea; Sidey, Jennifer A.; Mastorakos, Epaminondas

doi:10.1016/j.egypro.2017.07.167

Cited by 10 publications

(10 citation statements)

References 7 publications

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“…The stability mechanism of the LEAF has been discussed for gaseous fuels, 8 and an apparently identical mechanism was observed to apply to kerosene sprays, that is, the occurrence of the toroidal flame. This flame results from the sequential combustion of four individual sprays in the azimuthal direction as well as from the high amount of recirculation found in the axial direction.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

“…The resulting high-temperature reactants favor autoignition over flame propagation, generating a toroidal-like reaction zone. 8 In the present work, the LEAF combustor concept is advanced for kerosene spray operation, demonstrating the viability of such a low-emission concept as a liquid-fueled gas turbine combustor technology for aviation.…”

Section: ■ Introductionmentioning

confidence: 72%

“…At J5, a very uniform bright-blue ring is seen in the photographs, in contrast to visibly distinct interconnected flames seen in J2 and for gas operation. 8 This effect is associated with a decrease of the fuel penetration as ṁj ets increased, which occurred as a result of higher cross-flow velocities experienced by the spray. Additionally, it is clear that significantly less visible soot luminescence was achieved by increasing ṁj ets while keeping the global equivalence ratio ϕ constant.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…For the sake of clarity, it should be noted that previous experiments with methane 8 considered an overall equivalence ratio range of 0.5−0.75, top air jet velocities in the range of 13−90 m/s, core air flow velocities of 0.4−2.5 m/s, and pilot air velocities in the range of 0.8−2.5 m/s. While a very similar range of tangential velocities and core air flow velocities were used in both the liquid-fueled and gas-fueled experiments, significantly higher velocities of the top jets were needed in the present work, almost twice as high as those in gaseous experiments.…”

Section: ■ Methodsmentioning

confidence: 99%

“…6 Such characteristics are very attractive for the aviation sector 7 as well as the power generation sector. 2 Recently, a new combustor concept based on "flameless oxidation" was developed by the University of Cambridge, 8,9 denoted as the "lean azimuthal flame" (LEAF). Tests using CH 4 as fuel showed single-digit parts per million levels of NO, CO, and unburnt hydrocarbons, lower than those of a lean premixed flame.…”

Section: ■ Introductionmentioning

confidence: 99%

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Soot-Free Low-NO_x Aeronautical Combustor Concept: The Lean Azimuthal Flame for Kerosene Sprays

et al. 2021

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An ultralow emission combustor concept based on “flameless oxidation” is demonstrated in this paper for aviation kerosene. Measurements of gas emissions, as well as of the size and number of nanoparticles via scanning mobility particle sizing, are carried out at the combustor outlet, revealing simultaneously soot-free and single-digit NO x levels for operation at atmospheric conditions. Such performance, achieved with direct spray injection of the fuel without any external preheating or prevaporization, is attributed to the unique mixing configuration of the combustor. The combustor consists of azimuthally arranged fuel sprays at the upstream boundary and reverse-flow air jets injected from downstream. This creates locally sequential combustion, good mixing with hot products, and a strong whirling motion that increases residence time and homogenizes the mixture. Under ideal conditions, a clean, bright-blue kerosene flame is observed, free of soot luminescence. Although soot is intermittently formed during operation around optimal conditions, high-speed imaging of the soot luminescence shows that particles are subjected to long residence times at O2-rich conditions and high temperatures, which likely promotes their oxidation. As a result, only nanoparticles in the 2–10 nm range are measured at the outlet under all tested conditions. The NO x emissions and completeness of the combustion are strongly affected by the splitting of the air flow. Numerical simulations confirm the trend observed in the experiment and provide more insight into the mixing and air dilution.

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Section: ■ Results and Discussionmentioning

confidence: 92%

Section: ■ Introductionmentioning

confidence: 72%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Methodsmentioning

confidence: 99%