Effect of air humidity and natural gas composition on swirl burner combustion under unstable conditions

Cadavid, Yonatan; Obando, Julián; Vandel, Alexis; Cabot, Gilles; Amell, Andrés

doi:10.1016/j.fuel.2021.121601

Cited by 3 publications

(2 citation statements)

References 24 publications

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“…SETAI behavior has been proven to be affected by the equipment's structure and operation parameters, which provided the chance for SETAI control, but conflicting results have been observed with regard to the effect of the heat output [9][10][11], equivalent ratio (ϕ) [12][13][14], and system structure [15][16][17][18]. Due to insufficient knowledge, SETAI control is generally achieved via empirical or semi-empirical methods, mainly classified into two kinds of approaches.…”

Section: Introductionmentioning

confidence: 99%

Self-Excited Thermoacoustic Instability Behavior of a Hedge Premixed Combustion System with an Asymmetric Air/Fuel Supply or Combustion Condition

Du,

Zhang,

et al. 2023

Applied Sciences

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Self-excited thermoacoustic instability (SETAI) is an undesirable and dangerous phenomenon in combustion systems. However, its control is difficult, thus greatly limiting the development of combustion technology. Our previous works clarified how the premixed chamber length (LP) and equivalence ratio (φ) influence SETAI behavior in a symmetrical hedge premixed combustion system. On real-world sites, however, the supply structure or combustion condition in a multi-flame system could be asymmetric due to space limitations or combustion adjustment needs. This paper aims to clarify the SETAI behavior of a combustion system with an asymmetric supply structure or an asymmetric combustion condition. The results indicate that the sound pressure amplitude under strong oscillation can reach 160 dB, which is about 5% of the total pressure. The SETAI state under the asymmetric condition is determined by the coupling between the heat release oscillation and sound pressure oscillation on each side and their cooperation. The asymmetric supply structure leads to asynchronous heat release oscillations between the two sides; it may be that one promotes oscillation and that the other suppresses it, or that both have a promotion effect but with asynchronous action, thus partly canceling each other out to lower the system’s oscillation intensity. This brings an advantage for controlling SETAI, which can be achieved by only changing one side of the structure. The oscillation amplitude can be reduced by 80–90% by appropriately changing one LP only by ~20%. Under an asymmetric combustion condition with φ differing between the two sides, the heat release oscillation on each side is dependent on the local φ but not the global φ. Consequently, SETAI can also be controlled by changing the distribution but maintaining a constant fuel feeding rate and φ. The concepts identified in this paper demonstrate that SETAI can be effectively controlled by adopting an asymmetric φ distribution or an asymmetric structure of the supply system. This provides a convenient SETAI control approach without affecting the equipment’s thermal performance.

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Section: Introductionmentioning

confidence: 99%

Self-Excited Thermoacoustic Instability Behavior of a Hedge Premixed Combustion System with an Asymmetric Air/Fuel Supply or Combustion Condition

Du,

Zhang,

et al. 2023

Applied Sciences

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“…Results indicated that the CO2, N2 and O2 concentration could effectively change the instability characteristics and reduce oscillation amplitudes Liu et al 2021a;Liu et al 2021b). In addition, air humidity and fuel composition also presented excellent ability to inhibit combustion instability (Cadavid et al 2021). In general, the thermoacoustic system in a turbulent combustor is viewed as a complex system, the theoretical prediction and suppression methods are extremely complex.…”

Section: Introductionmentioning

confidence: 99%

Experimental Studies on Suppression of Combustion Instability with the Addition of Helium

2022

JAFM

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When combustion instability occurs, fluctuation in the release of heat couples with oscillating pressure, while the sensitivity of flame to acoustic disturbance restricts the oscillation intensity. This paper investigates the efficacy of helium in suppressing combustion instability. The flame structure, its sensitivity to acoustic disturbance and the inhibition of oscillating pressure with the addition of helium were studied by means of open tests, external-excited and self-excited combustion instability experiments. First of all, the addition of helium made larger flame surface area, which shaped the distributed flame, and the heat was such released over a broader space. Then, the external-exited combustion instability experiments confirmed that adding helium to fuel could decrease the sensitivity of flame to acoustic disturbance. Finally, Helium was used in the case of self-excited combustion instability to further investigate its effectiveness on the oscillation suppression. Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) methods were used to study flame fluctuation intensity. The results showed that the amplitudes of oscillating pressure were greatly reduced by the added helium. For 250Hz mode, adding helium with 20% of fuel flow could significantly reduce the flame pulsation and reduce the pulsation pressure by more than half. However, for the 160hz mode, more helium should be added to achieve better results. When the helium flow exceeded 80% of fuel flow, the combustion instability could be converted to stable combustion.

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Characterizing flow field transition in a pressurized tangential-injection gas-fired reactor

Sahu

Dewan

Kumar

2023

Thermal Science and Engineering Progress

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Effect of air humidity and natural gas composition on swirl burner combustion under unstable conditions

Cited by 3 publications

References 24 publications

Self-Excited Thermoacoustic Instability Behavior of a Hedge Premixed Combustion System with an Asymmetric Air/Fuel Supply or Combustion Condition

Self-Excited Thermoacoustic Instability Behavior of a Hedge Premixed Combustion System with an Asymmetric Air/Fuel Supply or Combustion Condition

Experimental Studies on Suppression of Combustion Instability with the Addition of Helium

Characterizing flow field transition in a pressurized tangential-injection gas-fired reactor

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