scholarly journals A non-premixed combustion model based on flame structure analysis at supercritical pressures

2012 ◽  
Vol 159 (6) ◽  
pp. 2087-2103 ◽  
Author(s):  
Guilhem Lacaze ◽  
Joseph C. Oefelein
Keyword(s):  
Structure Analysis ◽  
Flame Structure ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Model Based

CFD Simulation of Confined Non-Premixed Flames

2012 ◽  
Author(s):  
Tanaji M. Dabade ◽  
Xianchang Li ◽  
Daniel Chen ◽  
Helen Lou ◽  
Christopher Martin ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Flame Structure ◽  
Combustion Process ◽  
Premixed Combustion ◽  
Flame Height ◽  
Combustion Model ◽  
Ansys Fluent ◽  
Innovative Strategies ◽  
Precise Control ◽  
Fuel Jet

Material processing furnaces are the key component of the manufacturing industries. The burners used in these furnaces require precise control over the flame structure such as flame shape, height, and width. This study mainly focused on the simulation of the flame structure with Computational Fluid Dynamics (CFD) approach. ANSYS Fluent 13.0 was used to predict the flame characteristics in an enclosed cylinder. Non-premixed combustion model was applied to this combustion phenomenon. To control the flame structure, a micro jet at the centre of the burner is introduced. The effect on flame parameters with varying flow rates of micro jet, fuel jet and co-flow jet is examined. This study confirms the experimental study by Sinha et al. [1], which concluded that an air micro jet at the center of a non-premixed flame can control the flame height and luminosity. Moreover, this paper visualizes the thermo chemistry and transport phenomenon of non-premixed combustion process. Emissions from the combustion are monitored for different boundary conditions. This study shows that innovative strategies can be developed for the precise control over the different types of flames with the help of numerical modeling.

scholarly journals Numerical Investigation of Turbulent Premixed Combustion of Methane / Air in Low Swirl Burner under Elevated Pressures and Temperatures

2021 ◽  
Vol 39 (1) ◽  
pp. 155-160
Author(s):  
Akram Ben Ali ◽  
Mansour Karkoub ◽  
Mouldi Chrigui
Keyword(s):  
Flame Structure ◽  
Elevated Pressure ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Swirl Burner ◽  
Combustion Modeling ◽  
Eddy Simulation ◽  
Elevated Pressures ◽  
First Case

Turbulent combustion modeling of lean premixed methane/air gas mixture in a low swirl burner is carried out using Large Eddy Simulation (LES). The operating conditions of the experiment as well as simulation are carried out at elevated pressure and temperature. The first case-simulation is a premixed combustion model based on C-equation formulation, the second one is based on species transport – Eddy Dissipation Concept (EDC) model. Numerical results for axial velocity and turbulence intensity along the centerline showed a good agreement against the experimental data. Quantitative results of OH mass fraction contour showing the flame structure are in a plausible agreement compared to the experimental measurement.

scholarly journals Analysis of the partially premixed combustion in a labscale swirl-stabilized burner fueled by a methane-hydrogen mixture

2021 ◽  
Vol 312 ◽  
pp. 11004
Author(s):  
Michele Stefanizzi ◽  
Saverio Stefanizzi ◽  
Vito Ceglie ◽  
Tommaso Capurso ◽  
Marco Torresi ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Flame Structure ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Cold Flow ◽  
Partially Premixed Combustion ◽  
Energy Scenario ◽  
Partially Premixed ◽  
Technical Solutions ◽  
Combustion Processes

Nowadays hydrogen is gaining more and more attention by Industry, Academia and Politics. Being a carbon free fuel, it is supposed to have a key role in the future energy scenario, especially if produced by renewable sources. The use of mixtures of hydrogen and conventional hydrocarbons in gas turbines is one of the most promising technical solutions for obtaining a sustainable combustion during the transition toward a full decarbonization. For this reason, it is fundamental to investigate the behaviour of fuels enriched with hydrogen in combustion processes. In this work, a lab-scale swirled premixed burner has been investigated by means of a fully 3D URANS approach. Firstly, a numerical simulation with cold flow has been performed to validate the model against experimental data. Then, reactive flow simulations have been performed. Initially, a combustion with 100% methane was considered. Then, a 30% by volume hydrogen blending has been investigated. The partially premixed combustion model has been implemented to take into account the inhomogeneities of the mixture at the chamber inlet. The variation of the flame structure due to the hydrogen enrichment will be described in terms of the temperature and species concentration distributions.

scholarly journals Flow Inhomogeneities in a Realistic Aeronautical Gas-Turbine Combustor: Formation, Evolution and Indirect Noise

2018 ◽  
Author(s):  
Andrea Giusti ◽  
Luca Magri ◽  
Marco Zedda
Keyword(s):  
Gas Turbines ◽  
Transfer Functions ◽  
Guide Vane ◽  
Flame Structure ◽  
Combustion Noise ◽  
Moment Closure ◽  
Combustion Model ◽  
Conditional Moment ◽  
Eddy Simulation ◽  
Nozzle Guide

Indirect noise generated by the acceleration of combustion inhomogeneities is an important aspect in the design of aeroengines because of its impact on the overall noise emitted by an aircraft and the possible contribution to combustion instabilities. In this study, a realistic rich-quench-lean combustor is numerically investigated, with the objective of quantitatively analyzing the formation and evolution of flow inhomogeneities and determine the level of indirect combustion noise in the nozzle guide vane (NGV). Both entropy and compositional noise are calculated in this work. A high-fidelity numerical simulation of the combustion chamber, based on the Large-Eddy Simulation (LES) approach with the Conditional Moment Closure (CMC) combustion model, is performed. The contributions of the different air streams to the formation of flow inhomogeneities are pinned down and separated with seven dedicated passive scalars. LES-CMC results are then used to determine the acoustic sources to feed an NGV aeroacoustic model, which outputs the noise generated by entropy and compositional inhomogeneities. Results show that non-negligible fluctuations of temperature and composition reach the combustor’s exit. Combustion inhomogeneities originate both from finite-rate chemistry effects and incomplete mixing. In particular, the role of mixing with dilution and liner air flows on the level of combustion inhomogeneities at the combustor’s exit is highlighted. The species that most contribute to indirect noise are identified and the transfer functions of a realistic NGV are computed. The noise level indicates that indirect noise generated by temperature fluctuations is larger that the indirect noise generated by compositional inhomogeneities, although the latter is not negligible and is expected to become louder in supersonic nozzles. It is also shown that relatively small fluctuations of the local flame structure can lead to significant variations of the nozzle transfer function, whose gain increases with the Mach number. This highlights the necessity of an on-line solution of the local flame structure, which is performed in this paper by CMC, for an accurate prediction of the level of compositional noise. This study opens new possibilities for the identification, separation and calculation of the sources of indirect combustion noise in realistic aeronautical gas turbines.

Study of Model-based Cooperative Control of EGR and VGT for a Low-temperature, Premixed Combustion Diesel Engine

2001 ◽  
Author(s):  
Takashi Shirawaka ◽  
Manabu Miura ◽  
Hiroyuki Itoyama ◽  
Eiji Aiyoshizawa ◽  
Shuji Kimura
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Cooperative Control ◽  
Premixed Combustion ◽  
Model Based

Local flame structure analysis in turbulent CH4/air flames with multi-regime characteristics

2019 ◽  
Vol 210 ◽  
pp. 426-438 ◽  
Author(s):  
David Butz ◽  
Sandra Hartl ◽  
Sebastian Popp ◽  
Steffen Walther ◽  
Robert S. Barlow ◽  
...  
Keyword(s):  
Structure Analysis ◽  
Flame Structure

scholarly journals Large Eddy Simulation of Premixed Combustion With a Thickened-Flame Approach

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Ashoke De ◽  
Sumanta Acharya
Keyword(s):  
Large Eddy Simulation ◽  
Laminar Flame ◽  
Flame Structure ◽  
Reaction Rates ◽  
Premixed Combustion ◽  
Efficiency Function ◽  
Modeling Approach ◽  
Eddy Simulation ◽  
Reduced Chemistry ◽  
Large Eddy

A thickened-flame (TF) modeling approach is combined with a large eddy simulation (LES) methodology to model premixed combustion, and the accuracy of these model predictions is evaluated by comparing with the piloted premixed stoichiometric methane-air flame data of Chen et al. (1996, “The Detailed Flame Structure of Highly Stretched Turbulent Premixed Methane-Air Flames,” Combust. Flame, 107, pp. 233–244) at a Reynolds number Re=24,000. In the TF model, the flame front is artificially thickened to resolve it on the computational LES grid and the reaction rates are specified using reduced chemistry. The response of the thickened-flame to turbulence is taken care of by incorporating an efficiency function in the governing equations. The efficiency function depends on the characteristics of the local turbulence and on the characteristics of the premixed flame such as laminar flame speed and thickness. Three variants of the TF model are examined: the original thickened-flame model, the power-law flame-wrinkling model, and the dynamically modified TF model. Reasonable agreement is found when comparing predictions with the experimental data and with computations reported using a probability distribution function modeling approach. The results of the TF model are in better agreement with data when compared with the predictions of the G-equation approach.

The Effects of Turbulent Burning Velocity Models in a Swirl-Stabilized Lean Premixed Combustor

2018 ◽  
Vol 35 (4) ◽  
pp. 365-372
Author(s):  
Jong-Chan Kim ◽  
Won-Chul Jung ◽  
Ji-Seok Hong ◽  
Hong-Gye Sung
Keyword(s):  
Burning Velocity ◽  
Premixed Combustion ◽  
Dynamic Mode Decomposition ◽  
Combustion Model ◽  
Dynamic Mode ◽  
Turbulent Premixed Combustion ◽  
Velocity Models ◽  
Flame Structures ◽  
Turbulent Burning Velocity ◽  
Turbulent Premixed

Abstract The effects of turbulent burning velocities in a turbulent premixed combustion simulation with a G-equation are investigated using the 3D LES technique. Two turbulent burning velocity models – Kobayashi model, which takes into account the burning velocity pressure effect, and the Pitsch model, which considers the flame regions on the premixed flame structure – are implemented. An LM6000 combustor is employed to validate the turbulent premixed combustion model. The results show that the flame structures in front of the injector have different shapes in each model because of the different turbulent burning velocities. These different flame structures induce changes in the entire combustor flow field, including in the recirculation zone. The dynamic mode decomposition (DMD) method and linear acoustic analysis provide the dominant acoustic mode.

scholarly journals Flow Inhomogeneities in a Realistic Aeronautical Gas-Turbine Combustor: Formation, Evolution, and Indirect Noise

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Andrea Giusti ◽  
Luca Magri ◽  
Marco Zedda
Keyword(s):  
Gas Turbines ◽  
Transfer Functions ◽  
Guide Vane ◽  
Flame Structure ◽  
Combustion Noise ◽  
Moment Closure ◽  
Combustion Model ◽  
Conditional Moment ◽  
Eddy Simulation ◽  
Aero Engines

Indirect noise generated by the acceleration of combustion inhomogeneities is an important aspect in the design of aero-engines because of its impact on the overall noise emitted by an aircraft and the possible contribution to combustion instabilities. In this study, a realistic rich-quench-lean (RQL) combustor is numerically investigated, with the objective of quantitatively analyzing the formation and evolution of flow inhomogeneities and determining the level of indirect combustion noise in the nozzle guide vane (NGV). Both entropy and compositional noise are calculated in this work. A high-fidelity numerical simulation of the combustion chamber, based on the large-eddy simulation (LES) approach with the conditional moment closure (CMC) combustion model, is performed. The contributions of the different air streams to the formation of flow inhomogeneities are pinned down and separated with seven dedicated passive scalars. LES-CMC results are then used to determine the acoustic sources to feed an NGV aeroacoustic model, which outputs the noise generated by entropy and compositional inhomogeneities. Results show that non-negligible fluctuations of temperature and composition reach the combustor's exit. Combustion inhomogeneities originate both from finite-rate chemistry effects and incomplete mixing. In particular, the role of mixing with dilution and liner air flows on the level of combustion inhomogeneities at the combustor's exit is highlighted. The species that most contribute to indirect noise are identified and the transfer functions of a realistic NGV are computed. The noise level indicates that indirect noise generated by temperature fluctuations is larger than the indirect noise generated by compositional inhomogeneities, although the latter is not negligible and is expected to become louder in supersonic nozzles. It is also shown that relatively small fluctuations of the local flame structure can lead to significant variations of the nozzle transfer function, whose gain increases with the Mach number. This highlights the necessity of an on-line solution of the local flame structure, which is performed in this paper by CMC, for an accurate prediction of the level of compositional noise. This study opens new possibilities for the identification, separation, and calculation of the sources of indirect combustion noise in realistic aeronautical gas turbines.

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