A numerical investigation on NOX formation in counterflow n-heptane triple flames

Guo, Hongsheng; Smallwood, Gregory J.

doi:10.1016/j.ijthermalsci.2006.11.002

Cited by 10 publications

(14 citation statements)

References 37 publications

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“…In this study, the NO x formation submodel of Glarborg and co-workers was incorporated into the aforementioned fuel-related kinetic models. In order to identify the relative importance of each NO x formation route, the technique of Guo and Smallwood , was utilized, which involves a number of simulations. It is established now that the initiation steps for NO x formation are as follows (e.g., refs − ) normalN 2 + normalO → normalN + NO .25em ( Thermal route ) CH + normalN 2 → NCN + normalH .25em ( Prompt route ) normalN 2 + normalO + normalM → normalN 2 normalO + normalM .25em ( N 2 O route ) normalN 2 + OH → normalN 2 normalO + normalH .25em ( N 2 O route ) normalN 2 + normalO 2 → normalN 2 normalO + normalO .25em ( N 2 …”

Section: Modeling Approachmentioning

confidence: 99%

“…In this study, the NO x formation submodel of Glarborg and coworkers 45 was incorporated into the aforementioned fuelrelated kinetic models. In order to identify the relative importance of each NO x formation route, the technique of Guo and Smallwood 46,47 was utilized, which involves a number of simulations. It is established now that the initiation steps for NO x formation are as follows (e.g., refs 45−47)…”

Section: Modeling Approachmentioning

confidence: 99%

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Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Feng

Wang

Tsotsis

et al. 2012

Ind. Eng. Chem. Res.

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The nitrogen oxide formation characteristics of a class of model biodiesel fuels, namely fatty acid esters, were studied in both premixed and nonpremixed flames. The experiments were conducted in the opposed-jet configuration at atmospheric pressure and for various reactant concentrations. The measurements were performed using a quartz-probe sampling method. Flames of the model biodiesel fuels were determined to form significantly less nitrogen oxides when compared to the corresponding n-alkanes. Additional experimental studies were carried out in order to assess the effects of carbon number, type of ester group (methyl or ethyl), and the extent of saturation on the nitrogen oxide concentrations in flames of these model biodiesel fuels. Three recently developed chemical kinetic models were utilized in order to model the experiments and to investigate the relative contributions of the four different nitrogen oxide pathways to the nitrogen oxide formation in these flames as well as to provide insight into the differences that were determined experimentally in flames of the various model biodiesel fuels.

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Section: Modeling Approachmentioning

confidence: 99%

Section: Modeling Approachmentioning

confidence: 99%

Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Feng

Wang

Tsotsis

et al. 2012

Ind. Eng. Chem. Res.

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“…To model NO x formation, two different sets of kinetics are tested after they are incorporated into the aforementioned combined model, namely, the one included in GRI 3.0, hereinafter referred to as Model 1, and that of Glarborg and co-workers, referred to as Model 2. To identify the relative importance of each NO x formation route, the technique of Smallwood and co-workers , was utilized.…”

Section: Numerical Approachmentioning

confidence: 99%

Fundamental Study of the Oxidation Characteristics and Pollutant Emissions of Model Biodiesel Fuels

Feng

Wang

Egolfopoulos

et al. 2010

Ind. Eng. Chem. Res.

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In this study, the oxidation characteristics of biodiesel fuels are investigated with the goal of contributing toward the fundamental understanding of their combustion characteristics and evaluating the effect of using these alternative fuels on engine performance as well as on the environment. The focus of the study is on pure fatty acid methyl-esters (FAME,) that can serve as surrogate compounds for real biodiesels. The experiments are conducted in the stagnation-flow configuration, which allows for the systematic evaluation of fundamental combustion and emission characteristics. In this paper, the focus is primarily on the pollutant emission characteristics of two C 4 FAMEs, namely, methyl-butanoate and methyl-crotonate, whose behavior is compared with that of n-butane and n-pentane. To provide insight into the mechanisms of pollutant formation for these fuels, the experimental data are compared with computed results using a model with consistent C 1 -C 4 oxidation and NO x formation kinetics.

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“…The study is motivated by several considerations. The first is that fundamental flame investigations dealing with large hydrocarbons have mostly considered saturated fuels, such as heptane. − Another motivation is due to the importance of triple flames in numerous practical applications. Such flames play a fundamental role in characterizing lifted jet flames − as well as the propagation and stabilization of laminar and turbulent flames. , Such flames are also relevant to diesel engine combustion, especially in the context of novel low-temperature combustion concepts, including homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI), and dual-fuel injection.…”

Section: Introductionmentioning

confidence: 99%

“…Whereas triple flames burning smaller hydrocarbon fuels have been extensively investigated, there have been few studies dealing with large hydrocarbon fuels. Guo and Smallwood 16 numerically investigated n-heptane triple flames and observed that a large amount of prompt NO is formed in the rich premixed flame branch. They also discussed interactions involving heat and species transport between the three reaction zones.…”

Section: Introductionmentioning

confidence: 99%

Effect of Unsaturated Bond on NO_x and PAH Formation in n-Heptane and 1-Heptene Triple Flames

Aggarwal

Brezinsky

2013

Energy Fuels

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Various engine and shock tube studies have observed increased NO x emissions from the combustion of biodiesels relative to regular diesel and linked them to the degree of unsaturation or the number of double bonds in the molecular structure of long-chain biodiesel fuels. We report herein a numerical investigation on the structure and emission characteristics of triple flames burning n-heptane and 1-heptene fuels, which represent, respectively, the hydrocarbon side chain of the saturated (methyl octanoate) and unsaturated (methyl octenoate) biodiesel surrogates. Our objective is to examine the effect of unsaturated (double) bond on NO x and soot emissions in a flame environment containing regions of lean premixed, rich premixed, and nonpremixed combustion. A validated detailed kinetic model with 198 species and 4932 reactions was used to simulate triple flames in a counterflow configuration with different levels of premixing and strain rates. Results indicate that although the global structures of n-heptane and 1-heptene triple flames are quite similar, there are significant differences with respect to NO x and polycyclic aromatic hydrocarbon (PAH) emissions from these flames. The NO x production rates in the rich premixed, lean premixed, and nonpremixed zones are higher in 1-heptene flames than in n-heptane flames, and the differences become more pronounced as the level of premixing is increased. The NO x formed through the prompt, thermal, N2O, and NNH mechanisms is also higher in 1-heptene flames. NO x formation in the rich premixed zone is primarily due to the prompt NO, that in the nonpremixed zone is through the thermal NO, and that in the lean premixed zone is due to the NNH and N2O routes. The PAH species are mainly formed in the rich premixed zone, and their emissions are significantly higher in 1-heptene flames than in n-heptane flames. The reaction pathway analysis indicated that the dominant path for benzene formation involves the recombination of two propargyl (C3H3) radicals, and the presence of the double bond in 1-heptene provides a significant route for its production through the formation of C3H5. This path is not favored in the oxidation of n-heptane, as it decomposes directly to smaller alkyl radicals. Whereas the NO x and PAH emissions decrease with the increase in strain rate, they are consistently higher in 1-heptne flames than in n-heptane flames, irrespective of the strain rate.

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A numerical investigation on NOX formation in counterflow n-heptane triple flames

Cited by 10 publications

References 37 publications

Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Fundamental Study of the Oxidation Characteristics and Pollutant Emissions of Model Biodiesel Fuels

Effect of Unsaturated Bond on NO_x and PAH Formation in n-Heptane and 1-Heptene Triple Flames

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A numerical investigation on NOX formation in counterflow n-heptane triple flames

Cited by 10 publications

References 37 publications

Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Formation of Nitrogen Oxides in Flames of Model Biodiesel Fuels

Fundamental Study of the Oxidation Characteristics and Pollutant Emissions of Model Biodiesel Fuels

Effect of Unsaturated Bond on NOx and PAH Formation in n-Heptane and 1-Heptene Triple Flames

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Product

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Effect of Unsaturated Bond on NO_x and PAH Formation in n-Heptane and 1-Heptene Triple Flames