Determination of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si53.gif" display="inline" overflow="scroll"><mml:msub><mml:mrow><mml:mi>NO</mml:mi></mml:mrow><mml:mrow><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:math> emissions from strong swirling confined flames with an integrated CFD-based procedure

Frassoldati, Alessio; Frigerio, S.; Colombo, Emanuela; Inzoli, Fabio; Faravelli, Tiziano

doi:10.1016/j.ces.2004.12.038

Cited by 74 publications

(4 citation statements)

References 23 publications

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“…Enhances in H 2 concentration in the mixture increase the axial velocity and decreases the size and strength of the recirculation region. Similar behavior was reported in [34].…”

Section: A Flame Shapesupporting

confidence: 88%

Investigation of Swirl Stabilized CH4 Air Flame with Varied Hydrogen Content by using Computational Fluid Dynamics (CFD) to Study the Temperature Field and Flame Shape

Bouziane

Alami

Zaitri

et al. 2021

Eng. Technol. Appl. Sci. Res.

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In the current paper, numerical simulations of the combustion of turbulent CH4-H2 are presented employing the standard k-epsilon and the RNG k-epsilon for turbulence closure. The Fr-ED concept is carried out to account for chemistry/ turbulence interaction. The hydrogen content is varied in the fuel stream from 0% to 100%. The numerical solutions are validated by comparison with corresponding experimental data from the Combustion Laboratory of the University of Milan. The flow is directed radially outward. This method of fuel injection has been already been explored experimentally. The results show that the structure of the flame is described reasonably and both standard k-ɛ and RNG k- ɛ models can predict the flame shape. The general aspect of the temperature profiles is well predicted. The temperature profiles are indicating a different trend between CH4 and CH4/H2 fuel mixtures.

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“…Enhances in H 2 concentration in the mixture increase the axial velocity and decreases the size and strength of the recirculation region. Similar behavior was reported in [34].…”

Section: A Flame Shapesupporting

confidence: 88%

Investigation of Swirl Stabilized CH4 Air Flame with Varied Hydrogen Content by using Computational Fluid Dynamics (CFD) to Study the Temperature Field and Flame Shape

Bouziane

Alami

Zaitri

et al. 2021

Eng. Technol. Appl. Sci. Res.

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show abstract

“…Assuming that NO x production is mainly described by the Zeldovich mechanism, the temperature of the NO x formation zone in flames decreases with increasing the swirl intensity. The experiments and computations 23,24 demonstrated that NO x emissions decrease with increasing the swirl number, mainly because of the faster mixing with flue gases in the inner recirculation zone created by high swirling flows.…”

Section: Resultsmentioning

confidence: 99%

Experimental Study of Oxygen Enrichment Effects on Turbulent Non-premixed Swirling Flames

et al. 2013

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The current paper describes the effects of oxygen enrichment on flame stability and pollutant emissions for turbulent non-premixed swirling flames. The study is motivated by CO2 capture applications further to the increase of the CO2 concentration by the O2 addition. The burner configuration consists of two concentric tubes with a swirl placed in the annular part for air or oxygen–air. The exhaust gas compositions are measured using gas analyzers. OH chemiluminescence experiments are conducted to investigate the stability of flames. The measurements were performed for oxygen concentrations ranging from 21 to 30% by volume, with swirl numbers of 0.8 and 1.4 and global equivalence ratios of 0.8, 0.9 and 1. Results show that oxygen enrichment enhances combustion efficiency and flame stability. The increase of the oxygen concentration in air leads to a decrease of lift-off heights and fluctuations of the flame base. Increasing the swirl number significantly improves the flame stability. Experiments demonstrated that the CO2 emissions linearly increase with an increasing O2 content in the oxidant. The CO emissions are shown to decay exponentially, whereas the NO x emissions, mainly produced through the thermal pathway, increased exponentially with oxygen addition.

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“…The authors explain this evolution by the decrease of flame temperature induced by the swirl through the Zeldovich mechanism. Some authors as [10,42] by the experiments and computations demonstrated that NO x emissions decrease when the swirl number increases, mainly because of the better mixing with combustion products in the inner recirculation zone created by high swirling flows.…”

Section: Swirling Flows and Flamesmentioning

confidence: 99%

Introductory Chapter: Swirling Flows and Flames

Boushaki¹

2019

Swirling Flows and Flames

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Swirling flows are used in a very wide range of industrial applications. In non-reacting cases, examples of applications include vortex amplifiers and reactors, heat exchangers, jet pumps, cyclone separators, whirlpools, tornadoes, etc. In reacting cases, swirlers are widely used in combustion systems, such as gas turbines, industrial furnaces, boilers, gasoline and diesel engines and many other practical heating devices. Effects of using swirl on flow and combustion are significant and various and concern, for example, aerodynamics, mixing, flame stability, intensity of combustion and pollutant emissions. In this chapter, we are interested in the use of swirling flows in combustion systems. In industrial plants, the geometric methods of flame stabilization are based on increasing the residence time of reactive gases either by the wake effect bluff-body burner, by the flow rotation of reactants swirl burner or by a combination of these two mechanisms. Burners with helical flows generally referred to as the swirl burner have very wide applications in the industrial field. In the literature, many examples of uses of swirling jets are found as a means of controlling combustion [1-4]. Other studies focused on the swirl effect on the characteristics of lifted flames [5], stabilization and blow-out phenomenon [6-8] and pollutant emissions [9-13]. 2. Swirl generation techniques There are several ways to generate the rotation of a flow. They can be classified into three main categories:

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Determination of NOx emissions from strong swirling confined flames with an integrated CFD-based procedure

Cited by 74 publications

References 23 publications

Investigation of Swirl Stabilized CH4 Air Flame with Varied Hydrogen Content by using Computational Fluid Dynamics (CFD) to Study the Temperature Field and Flame Shape

Investigation of Swirl Stabilized CH4 Air Flame with Varied Hydrogen Content by using Computational Fluid Dynamics (CFD) to Study the Temperature Field and Flame Shape

Experimental Study of Oxygen Enrichment Effects on Turbulent Non-premixed Swirling Flames

Introductory Chapter: Swirling Flows and Flames

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