Thermoacoustic combustion instability of propane‐oxy‐combustion with CO<sub>2</sub>dilution: Experimental analysis

Abubakar, Zubairu; Mokheimer, Esmail M. A.

doi:10.1002/er.4980

Cited by 11 publications

(11 citation statements)

References 57 publications

(121 reference statements)

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“…Temperature and species fractions, that is, densityweighted average scalars, can be evaluated from the probability density function (PDF) and progress variable using Equation (24). Subscripts, u and b, in this expression correspond to unburnt and burnt mixtures, respectively.…”

Section: Numerical Modeling 221 | Governing Equationsmentioning

confidence: 99%

“…Among these, swirl-stabilized burners have been investigated the most for oxycombustion application. [13][14][15][16][17][18] Moreover, oxy-combustion of various fuels (eg, methane, [19][20][21] propane, [22][23][24] syngas, [25][26][27] ammonia, [28][29][30] and hydrogen [31][32][33] ) at varying combustion parameters, such as equivalence ratio (ϕ), oxygen fraction (OF), adiabatic flame temperature (T ad ), and flame speed (FS), has been examined as well. Most research is focused on methane, with fewer studies examining propane.…”

Section: Introductionmentioning

confidence: 99%

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Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

et al. 2021

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The combustion, exhaust-gas concentrations, and stability characteristics of premixed CO 2 -diluted oxy-propane (C 3 H 8 /O 2 /CO 2 ) flames were investigated computationally using large eddy simulations (LES) in a swirl-stabilized model gas-turbine combustor. The simulations were carried out for ranges of equivalence ratio (Φ: 0.26-0.80) and oxygen fraction (OF: 35%-60%) at a fixed bulk inlet velocity of 5.2 m/s. The results indicate that the reaction rates increase with the increase of Φ and OF. Flames of the same adiabatic flame temperature (T ad ) show similar macro-and flowfield-structures, in terms of flame shape, flow circulation, and temperature, and species distributions, irrespective of the values of Φ and OF. At higher T ad , the flames were observed to be more compact with reduced flame thickness and higher Damkohler number (Da). In all cases, Da > 1 were observed, indicating the dominance of reaction rate in oxy-propane flames than the diffusion rate. A secondary IRZ was also observed near the outlet of the combustor. Mixture composition and combustion temperature influence the CO concentration at the combustor exit. The highest CO emission was observed at 0.17 ppm for the flame with highest Φ and T ad , meanwhile no CO emission was seen for flames with high OF and low Φ among the studied cases. Highlights 1. Adiabatic flame temperature is a quantifying parameter for flame

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Section: Numerical Modeling 221 | Governing Equationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

et al. 2021

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“…Lean premixed combustion techniques are extensively employed in the power generation or aviation gas turbine combustors 1,2 . Due to the decreased equivalence ratio and the local flame temperature, the NO x formation would reduce exponentially in the lean premixed combustor.…”

Section: Introductionmentioning

confidence: 99%

“…Combustion instability is among the most critical operational challenges encountered in combustion systems of gas turbines, rockets, industrial boilers, furnaces and so on. Thermoacoustic instability can be formed with the coupling of sound pressure and heat release fluctuations in the combustion chamber 2 . These acoustic fluctuations may reach sufficient amplitude to interfere with gas turbine operation and, in extreme cases, lead to failure of the system due to excessive structural vibration and heat transfer to the chamber 3,4 .…”

Section: Introductionmentioning

confidence: 99%

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region

Tao

Zhou

2021

Asia-Pacific J Chem Eng

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The shear layer is a region between the internal and external recirculating zone of the flame, which is critical for combustion stabilization and emission. This study experimentally studied the effects of oxyfuel (CO2/O2) shear layer injections on combustion dynamics and pollutant emissions of a model gas turbine combustor. To evaluate the damping performances of ‘Oxy’ CO2/O2 shear layer jets on unsteady combustion and pollutant formation processes, four variables of the CO2/O2 shear layer injection system are studied—the flow rate, the inner diameter, the injection angle and the oxygen ratio. Experimental results show that thermoacoustic instability and NOx emissions can be suppressed with the ‘Oxy’ CO2/O2 shear layer injection method. The minimum inner diameter cases could achieve better control effectiveness of 80%, with the sound pressure amplitude drops from 27 to 5.4 Pa. The maximum inner diameter case could achieve better control effectiveness of 59.2%, with the concentration of NOx emissions drops from 25 to 10.2 ppm. Flame oscillation modes experienced shifting and switching under different shear layer angles and oxygen ratios. There exist extreme points that can be selected for a better control effect. The CO2/O2 shear layer injection splits the inner and outer recirculation zones of the flame. As the oxygen ratio of CO2/O2 varied from 36% to 46%, a flame flapping phenomenon emerged. The ‘Oxy’ CO2/O2 shear layer injection method could eliminate combustion instability and NOx emissions at a relatively lower cost and complexity, which will promote the development of high‐performance burners.

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“…The rise in the local flame temperature results in faster expansion of the reaction zone, inhibiting the cooler flow recirculation 11 . Effects of hydrogen enrichment on the flame shape and thermoacoustic oscillation dynamics of methane blends in lean premixed gas turbine combustion was studied by Karlis et al 25 It was found that increasing the H 2 content keeping other operational parameters constant, increases the extinction strain rate leading to dynamic state transition. Moreover, studies by Abubakar and Mokheimer 25 on the thermoacoustic instability of propane oxy‐combustion shows that the increase of hydrogen fraction in the fuel blend lowers the acoustic amplitude.…”

Section: Introductionmentioning

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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Thermoacoustic combustion instability of propane‐oxy‐combustion with CO₂dilution: Experimental analysis

Abstract: In this study, the effect of CO 2 dilution on the thermoacoustic stability of propane-oxyfuel flames is studied in a non-premixed, swirl-stabilized combustor. The results, obtained at a fixed combustor power density (4 MW/m 3 bar)

Cited by 11 publications

References 57 publications

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region

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

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Thermoacoustic combustion instability of propane‐oxy‐combustion with CO2dilution: Experimental analysis

Abstract: In this study, the effect of CO 2 dilution on the thermoacoustic stability of propane-oxyfuel flames is studied in a non-premixed, swirl-stabilized combustor. The results, obtained at a fixed combustor power density (4 MW/m 3 bar)

Cited by 11 publications

References 57 publications

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

Numerical analysis supported with experimental measurements of premixed oxy‐propane flames in a fuel‐flex gas turbine combustor

Mitigating combustion instability and NOx emissions with annular oxyfuel jets into the flame shear layer region

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

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Thermoacoustic combustion instability of propane‐oxy‐combustion with CO₂dilution: Experimental analysis

Mitigating combustion instability and NO_x emissions with annular oxyfuel jets into the flame shear layer region