The effects of fuel-air mixing on NOx formation in non-premixed swirl burners

Terasaki, Takashi; Hayashi, Shigeru

doi:10.1016/s0082-0784(96)80110-x

Cited by 55 publications

(23 citation statements)

References 1 publication

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“…From the above, the vast majority of studies on flame pulsation behavior were performed under the non-swirling conditions, while the puffing characteristics under swirl flame were still unknown. Swirl has widespread use in combustion systems, as it plays critical role in stabilizing flame, controlling the flame size and combustion intensity [22], and lowering NO x emissions [23,24]. Therefore, it is necessary to explore the flame flickering for swirl combustion.…”

Section: Introductionmentioning

confidence: 99%

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

et al. 2018

Energies

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Flame pulsation has a significant effect on combustion, and understanding its oscillatory behavior is important to the combustion community. An experiment was performed to analyze the pulsation characteristics of a swirl non-premixed flame under various parameters. The results showed that as fuel mass flow rate increased, the puffing frequency increased due to the decreased flame radiation fraction, and the puffing amplitude became smaller resulting in a more stable flame. With an increase in combustor pressure, the flickering frequency declined because of the increasing soot radiation, while the flickering amplitude uniformly increased, leading to more deteriorative flame stability. With an increment in mass flow rate of primary air, the puffing frequency decreased due to the enhanced mixing between fuel and primary air. Also, the puffing amplitude had an oscillating relationship with the mass flow rate of primary air. When the exit velocity of the injector was increased, the flickering frequency diminished nearly linearly because of the improving swirl intensity, and the flickering amplitude was approximately unaffected by injector exit velocity. Moreover, the measured puffing frequencies summarized over all cases varied within the range of 3-22 Hz, the predicted values from theoretical models based on non-swirl flame also fell within this range. The puffing frequency of swirl combustion was more sensitive to the variation in operating conditions than that of non-swirl combustion. Additionally, the obtained correlations indicated that the Strouhal number St was proportional to Fr −1.4 (the Froude number) and Re −2.9 (the Reynolds number), respectively.

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Section: Introductionmentioning

confidence: 99%

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

et al. 2018

Energies

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“…Experimental results show that NO, formation is influenced by the equivalence ratio, fiiel feed rate, the distribution of dispersion in diluted air, but the fiiel droplet diameter had the most significant effect on the change in NO, released [160]. In premixed or diffusion hydrocarbon flames, the main mechanisms of Low NO, emissions were also achieved by a non-premixed, direct fnel-injection burner, eqnipped with a unique double swirler for gas turbine combustors [35]. The buciier has circular and annular air channels to which swirlers are fitted.…”

Section: Impact Of No Emissions On Burner Technologymentioning

confidence: 96%

“…This secondary air serves two purposes: a) supplies more air to the combustion zone to allow higher firing rates without increasing the nozzle diameter and radiant and catalytic burners [33,34]. More details on burners and their applications are given elsewhere [35,36].…”

Section: ) Preparation Of Fuels For Oxidation: Atomization and Vapormentioning

confidence: 99%

Oxidation of Fuels in the Cool Flame Regime for Combustion and Reforming for Fuel Cells.

Naidja

Butcher²,

Mahajan

2002

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2 3 4 The pmpose of this review was to integrate the most recent and relevcant investigations on the auto-oxidation of fuel oils and their reforming into hydrogen-rich gas that conld serve as a feed for fiiel cells and combustion systems. We consider the incorporation of partial oxidation under cool flame conditions to be a significant step in the reforming process for generation of hydrogen-rich gas. Therefore, we have paid particnlm attention to the partial oxidation of fiiels at low temperatnre in the cool flame region. This is still not a well-understood featnre in the oxidation of fiiels and can potentially serve as a precursor to low NO, emissions and low soot formation. Pretreatment, including atomization, vaporization and burner technology are also briefly reviewed. The oxidation of reference fuels (n-heptane C7H16, iso-octane CaHls and to a lesser extent cetane Cl~H34) in the intermediate and high temperahire ranges have been stndied extensively and it is examined here to show the significant progress made in modeling the kinetics and mechanisms, and in the evaluation of ignition delay times. However, due to the complex nature of real fuels such as petroleum distillates (diesel and jet fuel)

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“…Additional studies have been done to evaluate the effects of air/fuel staged combustion technology on suppression of NO x for various combustion cases [3], [4]. And a great deal of efforts has been exercised to examine it by changing its aerodynamic characteristics, swirl number or flow velocity [5].…”

Section: Introductionmentioning

confidence: 99%

An Experimental Study on Industrial Boiler Burners Applied Low NOx Combustion Technologies

Lee¹,

Kim²,

Kwon³

2016

JOCET

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Abstract-Based on flue gas inner recirculation technology, a low NO x gas burner was developed and tested in a real scale industrial boiler. Some parts of combustion gases were recirculated in the combustion chamber and mixed with combustion air in the burner by its structural characteristics. And a noble low NO x combustion technology, based on partial oxidation combustion concept in a fuel rich combustion zone, was successfully applied in liquid burner. The burner was designed such that a portion of fuel is heated and pre-vaporized in the furnace then injected into a fuel rich combustion zone so that a partial oxidation reaction occurs. The effects of equivalence ratio, thermal load, and fuel distribution ratio on the emissions of NO x and CO were experimentally investigated. This newly developed combustion technologies showed very low NO x emission level, about 12 ppm when light oil was used as a fuel and about 18ppm when LNG was used as a fuel.

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The effects of fuel-air mixing on NOx formation in non-premixed swirl burners

Cited by 55 publications

References 1 publication

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

An Experimental Investigation on Flame Pulsation for a Swirl Non-Premixed Combustion

Oxidation of Fuels in the Cool Flame Regime for Combustion and Reforming for Fuel Cells.

An Experimental Study on Industrial Boiler Burners Applied Low NOx Combustion Technologies

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