Numerical simulation of a reversed flow small-scale combustor

Graça, Marcelo; Duarte, Armando C.; Coelho, Pedro J.; Costa, Mário

doi:10.1016/j.fuproc.2012.06.028

Cited by 45 publications

(26 citation statements)

References 45 publications

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“…For 21% oxygen, the ratio of minimum-maximum temperature was above 23% which is caused by the temperature rise almost exclusively being contained within r/D b < 2. In this study, the wall temperature was set at room temperature, so the temperature profiles are not as uniform as for a higher wall temperature of 1300K [41], with the largest variations occurring near the bluff body (Station A-A). The effect of air supply velocity on the flame temperature was very clear.…”

Section: Resultsmentioning

confidence: 99%

“…The chemical model used is the equilibrium chemistry model couple with the probability density function (PDF) model, as used for similar modelling in Refs. [14,41]. In the current work, 16 species were solved at 56 grid points in mixture fraction space for a range of enthalpies to yield 24,472 potential compositions in the PDF look-up table.…”

Section: Simulation Setupmentioning

confidence: 99%

See 1 more Smart Citation

Effect of Air-Fuel Ratio on Temperature Distribution and Pollutants for Biogas Mild Combustion

Noor¹,

Wandel

Yusaf³

2014

Int. J. Automot. Mech. Eng.

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This paper examines the effect of air-fuel ratio for Moderate or Intense Low oxygen Dilution (MILD) combustion using a bluff-body burner. Exhaust gas recirculation was used to dilute the oxidizer stream prior to the combustion chamber. A low-calorie biogas fuel which consists of 60% methane and 40% carbon dioxide were used in the simulations using a Reynolds-averaged Navier-Stokes model with the realizable k-ε turbulence model. The chamber temperature distribution was found to be in small ranges and almost homogeneously distributed, verifying that MILD conditions were attained. The performance was evaluated based on the level of pollutants (Unburned hydrocarbons (UHC) and carbon-mono oxide (CO)) produced and measured in the exhaust gas. Slightly lean conditions produced negligible pollutants with some excess oxygen measured in the exhaust gas. Under rich conditions, UHC and CO were produced, but when synthetic air containing oxygen with a mole fraction of 7% was used as the oxidizer instead of ordinary air, these levels were significantly reduced.

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Section: Resultsmentioning

confidence: 99%

Section: Simulation Setupmentioning

confidence: 99%

Effect of Air-Fuel Ratio on Temperature Distribution and Pollutants for Biogas Mild Combustion

Noor¹,

Wandel

Yusaf³

2014

Int. J. Automot. Mech. Eng.

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“…It has been successfully used in the wide range of applications utilizing MILD conditions; prototype gas turbines employing flameless oxidation [33], pulverized coal combustion in MILD conditions [34,35,36], MILD combustion in forward flow furnace of refinery-off gas [37], laboratory scale [38] or semi-industrial flameless furnaces [39] and other kind of MILD combustion devices [40,41,42].…”

Section: Introductionmentioning

confidence: 99%

“…However, a commonly reported problem [20,27,28,43,42,44,45] with EDC is that it tends to over-predict the maximum temperature values in the MILD regime. A solution proposed for the problem is to use a strongly modified set of constants for fine structures and residence time.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Eddy Dissipation Concept formulation for MILD combustion modelling

Lewandowski

Ertesvåg

2018

Fuel

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Performance of the Eddy Dissipation Concept (EDC) in the regime of Moderate and Intense Low-oxygen Dilution (MILD) combustion is investigated. The special MILD features, where chemical and turbulence time scales are comparable (Damköhler number close to unity), have led several researchers to suggest modifications of EDC, mainly by changing model constants. EDC with standard and modified constants are compared, and the importance of each effect is outlined. Different fine-structure reactor models and their inflow/initial conditions are discussed and found to play a significant role. The reacting fraction of fine structures, which in virtually all other numerical studies is set to unity, is also discussed and found to be important. We observe better agreement with experiment when the reacting fraction is reduced below unity, which is also described by the original EDC. The results obtained with the variable reacting fraction are found to improve both the temperature distributions and the lift-off height predictions. The calculations are carried out with the use of open source software OpenFOAM. The main test case was the Delft Jet-in-Hot-Coflow burner emulating MILD regime at three different flow conditions (jet Reynolds numbers of 2500, 4100 and 8800).

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“…In another work, Graça et al [15] simulated a reversed flow smallscale combustor using the realizable K − ϵ turbulence model and investigated the performance of two different combustion models of the eddy dissipation concept and the composition PDF model.…”

mentioning

confidence: 99%

Numerical Investigation of a Double-Swirled Gas Turbine Model Combustor Using a RANS Approach with Different Turbulence–Chemistry Interaction Models

Mardani

Fazlollahi-Ghomshi

2016

Energy Fuels

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In this work, numerical investigation of a gas turbine model combustor (GTMC) was carried out using two different turbulence-chemistry interaction models: the EDC (Eddy Dissipation Concept) and TPDF (Transported Probability Density Function). GTMC with a good optical access for laser measurements provides a useful database for swirling CH ସ /Air diffusion flames at atmospheric pressure. Modeling was performed by solving RANS and RSM equations for a 2D axisymmetric computational domain accompanied with swirl and the combustion chamber was investigated for both reacting and non-reacting conditions. A detailed reduced mechanism of DRM22 (with 22 species and 104 reactions) was used to represent the chemical reactions. Comprehensive comparisons were done for the predictions and measurements of velocity, mixture fraction, temperature, and chemical species concentrations of H ଶ , O ଶ , OH, H ଶ O, CH ସ , CO, and CO ଶ . Resultsshowed an acceptable accuracy of predictions by considering computational cost. That means that the simplified 2D-axismmetric-swirl simulation has the ability to capture some important features and structure of combustion field in a double highly swirled chamber, like GTMC, with much lower CPU time in comparison with costly 3D modellings, although misses some details of flow field characteristics in comparison with more accurate LES approach. In terms of comparison between the turbulence-chemistry interaction models, TPDF led to a good prediction for major species and flame structure near the inlets while the EDC predicted more accurately downstream of the flow field.

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Numerical simulation of a reversed flow small-scale combustor

Cited by 45 publications

References 45 publications

Effect of Air-Fuel Ratio on Temperature Distribution and Pollutants for Biogas Mild Combustion

Effect of Air-Fuel Ratio on Temperature Distribution and Pollutants for Biogas Mild Combustion

Analysis of the Eddy Dissipation Concept formulation for MILD combustion modelling

Numerical Investigation of a Double-Swirled Gas Turbine Model Combustor Using a RANS Approach with Different Turbulence–Chemistry Interaction Models

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