Study on Passive Control of the Self-excited Thermoacoustic Oscillations Occurring in Combustion Systems

Zhang, Yuanhang; Wang, Chang’An; Liu, Xuan; Du, Yongbo; Che, Defu

doi:10.1080/00102202.2021.1939322

Cited by 4 publications

(4 citation statements)

References 51 publications

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“…In addition, the acoustic wavelength (λ P ) within the premixed chamber can be calculated by the ratio of c mix within the premixed chamber to the oscillation frequency (f or f M ). This λ P is crucial for determining the pressure mode shape before the combustion chamber inlet, and thus influences the oscillation behavior through the Rayleigh criterion [24,25], as is also discussed in Section 4.1.…”

Section: Discussionmentioning

confidence: 99%

“…An exceptional circumstance occurs in cases 58 and 59, where both OS 1 and OS 2 have a promotion effect, but the whole system does not exhibit oscillation. This may be because the sound pressure antinode is too close to the stabilizer [24], resulting in a relatively weak flow rate oscillation and muting the thermo-acoustic interaction. These observations indicate that, for an asymmetric supply structure, a necessary but not sufficient condition for strong oscillation is that both L 1 and L 2 satisfy oscillation promotion.…”

Section: Setai Behavior Under Asymmetric Supply Structurementioning

confidence: 99%

“…Under an asymmetric combustion condition where ϕ varies between the two sides, the value of τ relies on the local ϕ, rather than the global ϕ. This is logical since the heat release at each flame should be controlled by the local ϕ, rather than being influenced by the total ϕ [24,26]. Consequently, the heat release oscillation differs between the two sides, even when there is an identical flow rate oscillation.…”

Section: Setai Behavior Under Asymmetric Combustion Conditionmentioning

confidence: 99%

“…Fully relating this phase difference to the operation parameters and structure dimensions is the key to solving this tough problem. Our previous work demonstrated that the premixed supply duct length (L P ), fuel flow rate (V F ), and ϕ have a coupled effect that allows for the identification of the phase difference between pressure and heat release oscillation [24,25] by introducing the flow rate oscillation at the combustion chamber inlet. This flow rate oscillation is caused by the pressure oscillation, and their phase difference [8] is determined by the sound pressure mode shape within the premixed duct [2], which is further collaboratively influenced by L P and V F .…”

Section: Introductionmentioning

confidence: 99%

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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: Discussionmentioning

confidence: 99%

Section: Setai Behavior Under Asymmetric Supply Structurementioning

confidence: 99%

Section: Setai Behavior Under Asymmetric Combustion Conditionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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Experimental studies on mechanism whereby premixed chamber length and equivalence ratio collaboratively influence self‐excited thermoacoustic instability

Zhang,

Du,

Zhang

et al. 2024

Asia-Pacific J Chem Eng

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Self‐excited thermoacoustic instability (SETAI) is a dangerous phenomenon in combustion equipment. While it is widely acknowledged that SETAI behavior is determined by the couple between pressure and heat release oscillation, their phase difference is difficult to predict, which impedes the development of SETAI control technology. With the aim of passive control technology development, this paper conducted experiment on a premixed hedge combustor to explore the mechanism whereby premixed chamber length (LP) and equivalence ratio (φ) collaboratively influence SETAI behavior. Results showed LP mainly affects the pressure mode shape within premixed chamber and consequently alters the phase difference between pressure and flowrate oscillation at combustion chamber inlet. Changing φ gives rise to different reaction time‐lag (τ), thus altering the phase difference between flowrate and reaction heat release oscillation. By introducing this flowrate oscillation, how LP and φ collaboratively determine phase difference between pressure oscillation and heat release oscillation was clarified. The mechanisms identified in this study are consistent with the emerging rationalization of the factors contributing to SETAI, and also provides better understanding on Rayleigh criterion and guidance for SETAI control. With further work on heat release and flow rate measurement, as well as the development on τ description, SETAI can be better predicted and controlled.

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Mechanism whereby fuel feeding rate influences self-excited thermoacoustic instability

Du,

Zhao,

Zhang

et al. 2025

International Journal of Thermal Sciences

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Study on Passive Control of the Self-excited Thermoacoustic Oscillations Occurring in Combustion Systems

Cited by 4 publications

References 51 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 mechanism whereby premixed chamber length and equivalence ratio collaboratively influence self‐excited thermoacoustic instability

Mechanism whereby fuel feeding rate influences self-excited thermoacoustic instability

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