Combustion Modeling Including Heat Loss Using Flamelet Generated Manifolds: A Validation Study in OpenFOAM

Ottino, GM; Fancello, A Alessio; Falcone, Manuel; Bastiaans, Rjm Rob; Goey, de Lph Philip

doi:10.1007/s10494-015-9666-5

Cited by 19 publications

(5 citation statements)

References 24 publications

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“…The modeling of non-premixed combustion, radiative heat transfer and conjugate heat transfer in OpenFOAM has recently attracted considerable attention. Examples of the development of OpenFoam-based solvers based on the flamelet generated manifold concept are found in [25,26] (and references cited therein). Solvers based on the alternative eddy-dissipation concept are developed in [27,28].…”

Section: Combustion Processes In Openfoammentioning

confidence: 99%

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Lahaye

Abbassi

Vuik

et al. 2020

Fluids

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This work studies how non-premixed turbulent combustion in a rotary kiln depends on the geometry of the secondary air inlet channel. We target a kiln in which temperatures can reach values above 1800 degrees Kelvin. Monitoring and possible mitigation of the thermal nitric-oxide (NOx) formation is of utmost importance. The performed reactive flow simulations result in detailed maps of the spatial distribution of the flow, thermodynamics and chemical conditions of the kiln. These maps provide valuable information to the operator of the kiln. The simulations show the difference between the existing and the newly proposed geometry of the secondary air inlet. In the existing configuration, the secondary air inlet is rectangular and located above the base of the burner pipe. The secondary air flows into the furnace from the top of the flame. The heat release by combustion is unevenly distributed throughout the flame. In the new geometry, the secondary air inlet is an annular ring placed around the burner pipe. The secondary air flows circumferentially around the burner pipe. The new secondary air inlet geometry is shown to result in a more homogeneous spatial distribution of the heat release throughout the flame. The peak temperatures of the flame and the production of thermal NOx are significantly reduced. Further research is required to resolve limitations of various choices in our modeling approach.

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Section: Combustion Processes In Openfoammentioning

confidence: 99%

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Lahaye

Abbassi

Vuik

et al. 2020

Fluids

View full text Add to dashboard Cite

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“…Zghal et al [29] evaluated the performance of FGM in predicting a micromix burner with pure hydrogen and showed that FGM can produce a reasonable result with a low computational cost. This popular combustion model regards the 3-D flame as an ensemble of several 1-D laminar flames, where the internal flame structure is not significantly impacted by turbulence [30]- [31]. FGM can evaluate 1-D flamelet based on 1-D premixed flame or 1-D diffusion approach.…”

Section: Figure 3 Side View Of Combustor Model With Mesh [19]mentioning

confidence: 99%

Co-Firing of Hydrogen and Natural Gas in a Practical DLN Combustor Model

Zhao,

Igie,

Abbott

et al. 2023

Volume 3B: Combustion, Fuels, and Emissions

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To reduce carbon dioxide emissions, the combustion of natural gas-hydrogen blends in a lean premix gas turbine combustor has been investigated. Previous studies have mostly investigated the fuel blends at relatively low pressure (up to 5 bar) with relatively low hydrogen concentrations (up to 50vol%) on lab-scale or generic burner configurations. However, the influence of higher pressure and higher hydrogen content (over 50vol%) has not been widely studied, particularly on a practical industry-scale lean premixed burner as presented in this study. Such an operation is more challenging as it increases the turbulent flame speed gradient, which is an important factor in determining the likelihood of boundary layer flashback. A preliminary RANS-based Computational Fluid Dynamics (CFD) study has been conducted using ANSYS Fluent 2021R1, employing the Realizable K-Epsilon turbulence model and the Flamelet-Generated Manifold (FGM) combustion model. The combustor consists of a diffusion pilot and premixed main fuel nozzles. Methane-hydrogen blends of up to 90vol% hydrogen were investigated at a fixed fuel energy input. 100vol% methane at 15 bar pressure was taken as the baseline reference case. To investigate the flame characteristics, contour plots of OH mass fraction, equivalence ratios and temperatures (at different planes) are presented. This study shows that the expected reduction in the flame length with increasing hydrogen concentration occurs up to 40vol%. Significantly different flame shapes (as indicated by OH contours) were seen at higher hydrogen content. For this model, the flashback occurred at 90vol% H2 as indicated by a premature development of the flame within the nozzle of the main fuel burner. NOx emissions are shown to progressively rise with increasing hydrogen content up to 60vol% but reduce as the hydrogen content increases to 70vol%. The decrease appears to be related to an improvement in the quality of fuel-air mixing. It is important to note that the apparent rate of increase in NOx with increasing hydrogen is dependent on the reporting approach used. When reporting conventionally (parts per million by volume corrected to 15% O2 on a dry basis) the increase is significantly greater than when reporting on a mass per fuel energy input basis (gram per Joule). Reporting in the conventional manner disadvantages hydrogen because of the impact of oxygen consumption and water production on the corrections.

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“…These are two widely used combustion models [5]- [6]. FGM assumes the 3-D flame as an ensemble of several 1-D laminar flames [17] and can account for detailed 1-D flame chemistry and the effects of convection and diffusion. In the FGM system, the flamelets are pre-processed by describing the thermochemical trajectories as a function of mixture fraction and progress variable (known as flamelet tables).…”

Section: Turbulence and Combustion Modelsmentioning

confidence: 99%

Hydrogen-Enriched Natural Gas Co-Firing: A Comparison of FGM and EDC Models

Zhao,

Igie,

Abbott

2023

Volume 3B: Combustion, Fuels, and Emissions

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To facilitate the transition from natural gas to a future hydrogen economy, the combustion of natural gas/hydrogen blends in gas turbines will play an important role in power generation. The influence of hydrogen content on technically premixed swirl-stabilized flame using large eddy simulation has proven to be powerful but with high computational costs. Hence, RANS-based models are useful for preliminary investigations and sensitivity studies. Flamelet Generated Manifold (FGM) and Eddy-Dissipation Concept (EDC) are two widely used RANS-based combustion models. EDC, in particular, accounts for the interaction between chemistry and turbulence using detailed chemical mechanisms, but at the cost of higher computational resources. FGM preprocesses the flamelet as a function of mixture fraction and progress variable and pre-integrates the chemistry-turbulence interaction into a Probability Density Functions (PDF) table, which makes FGM computationally inexpensive. This study aims to compare the predictions of these models with experimental data of a methane-fueled technically premixed swirl-stabilized low-pressure burner. The better-performing model is used to evaluate the influence of methane and hydrogen blends (up 40% by volume) in a higher-pressure burner also validated with experiments. The study has shown that EDC produces better agreement with the experimental data than FGM in estimating the flame temperature, flow velocity, and carbon dioxide profiles. FGM did not correctly capture the flame pattern and overestimated the reaction rate. This is possibly due to its simplified preprocessed chemistry mechanism, which could not evaluate the local thermal properties of the gas mixture properly. For the higher pressure evaluation at 5 bar, the EDC model captured the influence of hydrogen content addition on flame behaviour. As the hydrogen content increased, the chemical reaction rate increased, and the flame length indicated by OH decreased. This reduction in flame length is consistent with the experimental results. The CFD showed that at 20% H2, the change in NOx emission compared to 100% methane is negligible using the mass of NOx per unit of heat release calculation. A slight increase in NOx is shown for the same case using the concentration by volume corrected to 15% O2 approach. Nevertheless, both approaches showed NOx reductions at 40% H2. This study has shown that the behaviour of a technically premixed swirl-stabilized flame-firing methane/hydrogen blend is well represented by a non-adiabatic RANS-EDC model with low computation cost. This confirms its applicability in evaluating acceptable lean premixed burners characteristics for gas turbines.

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Combustion Modeling Including Heat Loss Using Flamelet Generated Manifolds: A Validation Study in OpenFOAM

Cited by 19 publications

References 24 publications

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Mitigating Thermal NOx by Changing the Secondary Air Injection Channel: A Case Study in the Cement Industry

Co-Firing of Hydrogen and Natural Gas in a Practical DLN Combustor Model

Hydrogen-Enriched Natural Gas Co-Firing: A Comparison of FGM and EDC Models

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