Operational characteristics of a parallel jet MILD combustion burner system

Szego, G.; Dally, Bassam B.; Nathan, Graham J.

doi:10.1016/j.combustflame.2008.08.009

Cited by 191 publications

(182 citation statements)

References 16 publications

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“…MILD combustion has also been studied in laboratory scale furnaces [17][18][19][20][21][22][23][24][25][26][27] and semi-industrial scale furnaces. For example, Orsino and Weber [24] investigated a semi-industrial scale burner using three different turbulent-chemistry interaction models (Eddy Break up Model (EBU), Eddy Dissipation Concept (EDC) and presumed PDF with equilibrium chemistry).…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence–Chemistry Interaction

Oldenhof

Sathiah

et al. 2011

Flow Turbulence Combust

189

173

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In this paper, we report results of a numerical investigation of turbulent natural gas combustion for a jet in a coflow of lean combustion products in the Delft-Jet-in-Hot-Coflow (DJHC) burner which emulates MILD (Moderate and Intense Low Oxygen Dilution) combustion behavior. The focus is on assessing the performance of the Eddy Dissipation Concept (EDC) model in combination with two-equation turbulence models and chemical kinetic schemes for about 20 species (Correa mechanism and DRM19 mechanism) by comparing predictions with experimental measurements. We study two different flame conditions corresponding to two different oxygen levels (7.6% and 10.9% by mass) in the hot coflow, and for two jet Reynolds number (Re = 4,100 and Re = 8,800). The mean velocity and turbulent kinetic energy predicted by different turbulence models are in good agreement with data without exhibiting large differences among the model predictions. The realizable k-ε model exhibits better performance in the prediction of entrainment. The EDC combustion model predicts too early ignition leading to a peak in the radial mean temperature profile at too low axial distance. However the model correctly predicts the experimentally observed decreasing trend of lift-off height with jet Reynolds number. A detailed analysis of the mean reaction rate of the EDC model is made and as possible cause for the deviations between model predictions and experiments a low turbulent Reynolds number effect is identified. Using modified EDC model constants prediction of too early ignition can be avoided. The results are weakly sensitive to the sub-model for laminar viscosity and laminar diffusion fluxes.

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Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence–Chemistry Interaction

Oldenhof

Sathiah

et al. 2011

Flow Turbulence Combust

189

173

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“…Se caracteriza porque la zona de reacción ocurre en todo el volumen de la cámara de combustión, sin la formación de frente de llama, ni ocurrencia de gradientes de temperatura significativos. Con la combustión sin llama se logra alcanzar simultáneamente alta eficiencia energética y muy reducidas emisiones de óxidos nitrosos (NOx) y monóxido de carbono (CO), así como calentamiento más uniforme, entre otras ventajas (Lupant et al, 2007;Szegö et al, 2008;Effuggi et al, 2008).…”

Section: Introductionunclassified

“…Si bien en los últimos diez años la combustión sin llama ha sido intensamente estudiada, aun su fenomenología y características no han sido del todo comprendidas (Effuggi et al, 2008;Szegö et al, 2008). Sin embargo, el desarrollo tecnológico de equipos de combustión y calentamiento que operan en este nuevo régimen de combustión se ha incrementado significativamente y cada día se identifican nuevos campos para su aplicación (Szegö et al, 2008).…”

Section: Introductionunclassified

“…Sin embargo, el desarrollo tecnológico de equipos de combustión y calentamiento que operan en este nuevo régimen de combustión se ha incrementado significativamente y cada día se identifican nuevos campos para su aplicación (Szegö et al, 2008). No obstante lo anterior, en la literatura no se encuentra una descripción sistemática y coherente de una metodología cuya aplicación garantice el desarrollo de equipos para la obtención de la combustión sin llama.…”

Section: Introductionunclassified

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Metodología para el Desarrollo de Sistemas de Combustión Sin Llama

et al. 2010

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ResumenEste trabajo presenta el desarrollo de una metodología para el diseño de equipos de calentamiento de combustión sin llama. El diseño de equipos de combustión sin llama requiere de metodologías apropiadas que garanticen las condiciones necesarias para alcanzar este modo de combustión. No obstante, estas metodologías no se encuentran disponibles en la literatura científica. Para esto se ha empleado la combinación del escalamiento dinámico, en función de la relación de impulsos de aire/gas, y el uso de la simulación numérica con el software FLUENT® para obtener configuraciones y dimensiones geométricas adecuadas para la descarga del combustible y comburente. La metodología desarrollada ha sido aplicada en el diseño de un horno experimental de 20 kW que utiliza gas natural, verificándose experimentalmente su validez con la obtención del régimen de combustión sin llama de forma estable. Palabras clave: combustión sin llama, equipos de calentamiento, transferencia de calor, simulación numérica Methodology to Develop Flameless Combustion Devices AbstractA methodology to design flameless combustion heating equipment is presented. The design of flameless combustion devices requires an appropriate methodology to guarantee the necessary conditions to obtain this combustion mode. Nevertheless, such methodologies are not available in the scientific literature. For this, a combination of dynamic scaling, based on air/gas impulse ratio, and numerical simulation with FLUENT® has been employed to get suitable geometric configurations and dimensions for discharging fuel and comburent air. The proposed methodology has been applied to the design of a 20 kW experimental furnace using natural gas as fuel. The validity of the methodology has been verified with stable flameless combustion operation in the furnace.

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“…In furnaces employing these combustion technologies, dilution with burned gas is realized by mean of a burner characterized by separate fuel and oxidizer nozzles. Fuel and oxidizer gases supplied from these nozzles mix with recirculated burned gases through entrainment by each jet until the bent fuel jet merges with the oxidizer jet (Mancini et al, 2007, Szegö et al, 2009. Mixing with the recirculated burned gas dilutes both the fuel gas and the oxidizing gas while simultaneously raising the temperatures of the diluted gases, thus achieving a uniform temperature distribution throughout the furnace and allowing a low flame temperature.…”

Section: Introductionmentioning

confidence: 99%

Effect of the distance between fuel and oxidizer nozzles on NOx emissions from spray combustion furnaces incorporating high-temperature preheated oxidizers

Nada

Shibata

Imaoka

et al. 2015

JTST

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The objective of the present study was to investigate the effect of the distance between fuel and oxidizer nozzles on NOx emissions from a laboratory-scale spray combustion furnace simulating an industrial high-temperature air combustion (HiTAC) furnace. The furnace employed in these trials was fueled with commercially obtainable kerosene in combination with highly preheated oxidizer gases. The oxidizer was pre-diluted by the addition of nitrogen in order to produce dilution levels equivalent to those in industrial HiTAC furnaces. The resulting NOx measurements indicate a trend opposite to that reported by previous studies, such that increasing the distance between the nozzles increases the NOx emissions, and a theory is advanced to explain this unusual observation. In a furnace within which the nozzle distance in the burner is small, the properties of the oxidizer supplied from the nozzle located near the spray nozzle greatly affect NOx emissions. The use of an oxidizer with a much lower preheat temperature and a lower O 2 concentration induces flame lifting further downstream, which significantly reduces NOx emissions through the formation of an invisible flame exhibiting a uniform temperature distribution throughout the furnace. In contrast, in a furnace in which the burner has a large nozzle distance, a highly luminous flame is anchored near the spray nozzle exit due to ignition of fuel vapor by high-temperature burned gases recirculated to the lower section of the furnace. This flame represents a zone with high combustion intensity and generates significant NOx emissions. In such cases, the influence of the oxidizer properties is moderated due to the widely separated nozzle locations.

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Operational characteristics of a parallel jet MILD combustion burner system

Cited by 191 publications

References 16 publications

Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence–Chemistry Interaction

Numerical Simulation of Delft-Jet-in-Hot-Coflow (DJHC) Flames Using the Eddy Dissipation Concept Model for Turbulence–Chemistry Interaction

Metodología para el Desarrollo de Sistemas de Combustión Sin Llama

Effect of the distance between fuel and oxidizer nozzles on NOx emissions from spray combustion furnaces incorporating high-temperature preheated oxidizers

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