On the characteristic flow and flame times for scaling oxy and air flame stabilization modes in premixed swirl combustion

Taamallah, Soufien; Chakroun, Nadim W.; Watanabe, Hirotatsu; Shanbhogue, Santosh J.; Ghoniem, Ahmed F.

doi:10.1016/j.proci.2016.07.022

Cited by 38 publications

(24 citation statements)

References 16 publications

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“…66,78,[87][88][89][90] Temperature profiles were found to be matched in CH 4 /air and CH 4 / 36%O 2 /64%CO 2 flames, according to Song et al 66 Comparable values were reported in the literature. 59,63,91,92 Rashwan et al 93 reported similar findings; an oxygen fraction of 29% to 40% is needed for stable oxy-combustion with FGR. Moreover, oxy-combustion limits the combustor stability window, because of the negative impact of adding CO 2 on the combustion kinetics.…”

Section: Premixed Oxy-fuel Combustionmentioning

confidence: 68%

“…The adiabatic flame temperature (T ad ) of the reactant mixture was adjusted through the oxygen fraction. 59,63,91,92 Rashwan et al 93 reported similar findings; an oxygen fraction of 29% to 40% is needed for stable oxy-combustion with FGR. The above finding was supported by high-speed images that showed similar vortex collapse modes.…”

Section: Premixed Oxy-fuel Combustionmentioning

confidence: 76%

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Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review

et al. 2019

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Summary The use of fossil fuel is expected to increase significantly by midcentury because of the large rise in the world energy demand despite the effective integration of renewable energies in the energy production sector. This increase, alongside with the development of stricter emission regulations, forced the manufacturers of combustion systems, especially gas turbines, to develop novel combustion techniques for the control of NOx and CO2 emissions, the latter being a greenhouse gas responsible for more than 60% to the global warming problem. The present review addresses different burner designs and combustion techniques for clean power production in gas turbines. Combustion and emission characteristics, flame instabilities, and solution techniques are presented, such as lean premixed air‐fuel (LPM) and premixed oxy‐fuel combustion techniques, and the combustor performance is compared for both cases. The fuel flexibility approach is also reviewed, as one of the combustion techniques for controlling emissions and reducing flame instabilities, focusing on the hydrogen‐enrichment and the integrated fuel‐flexible premixed oxy‐combustion approaches. State‐of‐the‐art burner designs for gas turbine combustion applications are reviewed in this study, including stagnation point reverse flow (SPRF) burner, dry low NOx (DLN) and dry low‐emission (DLE) burners, EnVironmental burners (including EV, AEV, and SEV burners), perforated plate (PP) burner, and micromixer (MM) burner. Special emphasis is made on the MM combustor technology, as one of the most recent advances in gas turbines for stable premixed flame operation with wide turndown and effective control of NOx emissions. Since the generation of pure oxygen is prerequisite to oxy‐combustion, oxygen‐separation membranes became of immense importance either for air separation for clean oxy‐combustion applications or for conversion/splitting of the effluent CO2 into useful chemical and energy products. The different carbon‐capture technologies, along with the most recent carbon‐utilization approaches towards CO2 emissions control, are also reviewed.

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Section: Premixed Oxy-fuel Combustionmentioning

confidence: 68%

Section: Premixed Oxy-fuel Combustionmentioning

confidence: 76%

Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review

et al. 2019

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“…A 55° axial‐swirler is installed to introduce the required swirl to the reactant gases. The swirl number of the flow can be estimated using the following Equation 32 :

italicSN = \frac{2}{3} ([], \frac{1 - {((), \frac{D_{cb}}{D_{in}})}^{3}}{1 - {((), \frac{D_{cb}}{D_{in}})}^{2}}) \tan ((), α_{italicsw}) = 0.98,

…”

Section: Methodsmentioning

confidence: 99%

“…The weighted sum of gray gas model was used to calculate the absorption coefficient of the gaseous mixture. The validity of the model can be found in literatures 31,32 . Flow turbulence was solved using the LES model, which resolves the large eddies directly and models the smaller eddies in the flow.…”

Section: Numerical Modelingmentioning

confidence: 99%

Operability of a premixed combustor holding hydrogen‐enriched oxy‐methane flames: An experimental and numerical study

et al. 2020

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Summary This work presents a detailed investigation on the stability, flame macrostructure and combustion characteristics of oxy‐methane/hydrogen (H2CH4O2CO2) flames in a premixed swirl‐stabilized model gas turbine combustor. The effects of equivalence ratio, inlet Reynolds number and inlet swirl number on stability and combustion characteristics were examined experimentally and numerically. A base operation case was selected as a reference to study the effects of the different parameters with equivalence ratio of 1.0, bulk mean throat velocity of 5.2 m/s, and swirl number of 0.98. Fixed compositions of the oxidizer (30%O2/70%CO2) and fuel (50%H2/50%CH4) streams were considered throughout the study. Large eddy simulation (LES) technique was adopted to compute the premixed turbulent flame regime. Experimentally captured flame images were compared with the flame contours obtained from the numerical simulations, and good conformations were observed. The results showed that near‐stoichiometry flames exhibit strong inner recirculation zone (IRZ) and are stabilized between two shear layers. At lower equivalence ratios, the flames are corner‐stabilized, and the flow is dominated by a single primary eddy in the IRZ. The calculated strain rates predict flame quenching at equivalence ratio of 0.5, which was also confirmed experimentally. It was observed that the effect of Reynolds number on the flame shape is not significant; however, the flow is dominated by larger primary eddy with strong IRZ as the Reynolds number increases. The IRZ also gets stronger with the increase in the flow swirl number. At higher swirl numbers, the flame stabilization occurs at the inner shear layer and the outer recirculation zone (ORZ) diminishes. It was found that the chemical time scale for all cases under investigation is shorter than the Kolmogorov time scale, signifying that the chemical reactions are dominated by the laminar flame speed.

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“…1) similar to the one used in our recent studies. 43,44 A circular 38 mm inner diameter stainless steel premixing tube starts with a choke plate, whose purpose is to prevent acoustic fluctuations from affecting the equivalence ratio. The inlet tube contains an axial swirler with a streamlined centerbody.…”

Section: A Experimental Apparatusmentioning

confidence: 99%

Helical vortex core dynamics and flame interaction in turbulent premixed swirl combustion: A combined experimental and large eddy simulation investigation

et al. 2019

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In this study, a combined experimental and Large Eddy Simulation (LES) investigation is performed to identify the vortical structures, their dynamics, and interaction with a turbulent premixed flame in a swirl-stabilized combustor. Our non-reacting flow experiment shows the existence of large scale precessing motion, commonly observed for such flows. This off-axis precessing dynamics disappears with combustion but only above a critical equivalence ratio at which the flame attaches to the swirler centerbody and vortex breakdown changes from a cone to a bubble type. For compact flames stabilized along the inner shear layer (ISL), no precessing is seen, but large scale vortices along the ISL are observed; these structures interact with the ISL-stabilized flame and contribute to its wrinkling as revealed by laser-induced fluorescence data. After validating the LES results in terms of low order statistics and point temperature measurements in relevant areas of the flow, we show that it can capture the precessing motion in the non-reacting flow and its suppression with combustion. The simulations show that the ISL vortices in the reacting case originate from a vortex core that is formed at the swirler's centerbody. This vortex core has a conical helical shape that interacts-as it winds outwith the ISL and the flame stabilized along it. The simulated helical vortex core (HVC) exists in both reacting and non-reacting flows; in the latter, it is dominated by the offaxis motion, whereas in the reacting case, that motion is damped and only remains the corkscrew type solid body rotation of the HVC.

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On the characteristic flow and flame times for scaling oxy and air flame stabilization modes in premixed swirl combustion

Cited by 38 publications

References 16 publications

Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review

Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review

Operability of a premixed combustor holding hydrogen‐enriched oxy‐methane flames: An experimental and numerical study

Helical vortex core dynamics and flame interaction in turbulent premixed swirl combustion: A combined experimental and large eddy simulation investigation

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On the characteristic flow and flame times for scaling oxy and air flame stabilization modes in premixed swirl combustion

Cited by 38 publications

References 16 publications

Frontiers in combustion techniques and burner designs for emissions control and CO2capture: A review

Frontiers in combustion techniques and burner designs for emissions control and CO2capture: A review

Operability of a premixed combustor holding hydrogen‐enriched oxy‐methane flames: An experimental and numerical study

Helical vortex core dynamics and flame interaction in turbulent premixed swirl combustion: A combined experimental and large eddy simulation investigation

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Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review

Frontiers in combustion techniques and burner designs for emissions control and CO₂capture: A review