A comparative study of turbulence models for non-premixed swirl-stabilized flames

Safavi, Mohammad; Amani, E.

doi:10.1080/14685248.2018.1527033

Cited by 16 publications

(5 citation statements)

References 78 publications

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“…𝐶𝐶 𝜇𝜇 is assumed as the local average flow deformation, and equations involving 𝜀𝜀 are optimized for circular jet flow equations. For turbulent swirling non-premixed flames, which are similar to the flame in the present boiler, the realizable 𝑘𝑘-𝜀𝜀 model yields the better flow field predictions, while the RNG model is the worst (Van Maele et al, 2003;Safavi et al, 2018). Thus, the realizable 𝑘𝑘-𝜀𝜀 model was chosen here.…”

Section: Governing Equationsmentioning

confidence: 99%

Effects of hydrogen addition on NOx formation in a non-premixed methane low-NOx combustor

CHENG,

ZHU,

DENG

2024

Mechanical Engineering Journal

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Hydrogen is a promising carbon-free fuel, but nitric oxides (NO x ) emissions are significantly increased with higher temperature in hydrogen combustion. Internal flue gas recirculation (IFGR) is one of the most effective NO x reduction techniques in boilers. Previous research has widely reported NO x generation with hydrogen enrichments from a chemical kinetic perspective, however, the NO x formation principles in non-premixed methane/air combustion using IFGR with hydrogen addition are still unclear. This work aims to investigate the effects of hydrogen addition on NO x formation in a non-premixed methane low-NO x combustor using IFGR. The Reynolds-averaged Navier-Stokes (RANS) simulations were conducted on a 5 kW non-premixed combustor with IFGR rate of 17.7%, which generated 11.3 mg/m 3 of total NO x generation in methane combustion. A series of three-dimensional computational fluid dynamics (CFD) simulations with detailed mechanisms was tested on four hydrogen power fractions. The reaction intensities of the main NO x formation pathways were analyzed on reaction rates. The results show that 70% hydrogen power fractions lead to significantly greater NO x concentration to 677.8 mg/m 3 , as high as 60 times of the original concentration. With no additional techniques, the original methane low-NO x combustor is only allowed for hydrogen addition of less than 20% power fraction. The NNH route becomes the second dominant pathway in hydrogen-added flames. Influenced by the growing hydrogen contents, the generation of the NNH route is largely generated from 2 mg/m 3 to 65 mg/m 3 . This work connects the hydrogen addition and the NO x formation pathways in non-premixed methane combustion, and highlights the importance of eliminating thermal NO x and the NNH route to achieve low-NO x combustion rather than sole NO x suppression method, which can provide a reference for designing low-NO x techniques.

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Section: Governing Equationsmentioning

confidence: 99%

Effects of hydrogen addition on NOx formation in a non-premixed methane low-NOx combustor

CHENG,

ZHU,

DENG

2024

Mechanical Engineering Journal

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“…Other forms of the SAS approach can be found within the research literature (Menter and Egorov, 2010). The SAS-SST model can produce accurate results when it is applied to flows with strong separation and unsteadiness, such as bluff-body flows (Derakhshandeh et al, 2014;Maleki et al, 2017;Rezaeiha et al, 2019) and combustion flows (Buhl et al, 2017;Egorov et al, 2010;Safavi and Amani, 2018). In fact, the SAS-SST model performs similarly to DES/IDDES models for strong unsteady flows (Liu et al, 2017;Wang et al, 2017;Zheng et al, 2016).…”

Section: Effects Of Entry Flow Profiles On the Qois And Uncertainty Q...mentioning

confidence: 99%

Non-intrusive semi-analytical uncertainty quantification using Bayesian quadrature with application to CFD simulations

Duan

Ridao

Eaton

et al. 2022

International Journal of Heat and Fluid Flow

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“…The configuration of swirl-stabilized flames is one of the most difficult experimental studies to verify with different turbulence and combustion models [10]. Many working groups have been working on the modeling and verification of these isothermal and reacting experimental studies for about 20 years.…”

Section: Introductionmentioning

confidence: 99%

Validation of Bluff-body Swirling Flame with RANS Turbulent Model and Comparison of the Results with LES Turbulent Model

Kazancı,

Böke

2024

International Journal of Thermodynamics

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The energy required for technological advancement is primarily derived from hydrocarbon combustion, which is a key topic in thermodynamics. The stability of the flame in hydrocarbon combustion is a critical parameter that impacts both burner design and combustion efficiency. Various methods have been employed in the literature to achieve a stable flame, with swirl flow being one technique that enhances combustion performance in engineering applications. This study focuses on the numerical analysis of the SM1 flame from Sydney swirl flames. Initially, the flow incorporating the two-equation Re-Normalization Group (RNG) k-ε and Shear Stress Transport (SST) k-ω turbulence models, along with the chemical reactions of CH4 combustion using the GRI 3.0 reaction mechanism, was modeled and compared with experimental data. Subsequently, the numerical results obtained from the Shear Stress Transport k-ω turbulence model, which demonstrated the best agreement with experimental data, were compared with results from a numerical analysis in the literature using the Large Eddy Simulation (LES) turbulence model. The predictive capabilities of these two turbulence models, along with their behavior in the flow region, were evaluated. The comparison revealed that for stable flames within the Sydney swirl flame family, the Shear Stress Transport k-ω turbulence model, which provides results in a more efficient manner, is sufficient compared to the computationally expensive Large Eddy Simulation turbulence model. This choice is made possible by utilizing a solution algorithm tailored to the flow characteristics and appropriate boundary conditions.

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A comparative study of turbulence models for non-premixed swirl-stabilized flames

Cited by 16 publications

References 78 publications

Effects of hydrogen addition on NO<i><sub>x</sub></i> formation in a non-premixed methane low-NO<i><sub>x</sub></i> combustor

Effects of hydrogen addition on NO<i><sub>x</sub></i> formation in a non-premixed methane low-NO<i><sub>x</sub></i> combustor

Non-intrusive semi-analytical uncertainty quantification using Bayesian quadrature with application to CFD simulations

Validation of Bluff-body Swirling Flame with RANS Turbulent Model and Comparison of the Results with LES Turbulent Model

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