The thermoacoustic instability in a stratified swirl burner and its passive control by using a slope confinement

Song, Heng; Lin, Y.; Han, Xiao; Yang, Dong; Zhang, Chi; Sung, Chih-Jen

doi:10.1016/j.energy.2020.116956

Cited by 20 publications

(5 citation statements)

References 48 publications

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“…To shed lights on the generation and damping of thermoacoustic instability, Rayleigh index analysis is then conducted to further characterize self-sustained thermos-acoustic coupling [40]. The Rayleigh index is widely applied to indicate the unsteady coupling nature between pressure and heat release perturbation [41]. The local Rayleigh index distribution can be calculated as [42]:…”

Section: Further Investigations Into the Heat Exchanger Temperature T H Effectmentioning

confidence: 99%

Generation and Mitigation Mechanism Studies of Nonlinear Thermoacoustic Instability in a Modelled Swirling Combustor with a Heat Exchanger

2021

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In the present work, 3D Unsteady Reynolds-Averaged Navier-Stokes (URANS) simulations are performed to investigate the generation and mitigation mechanism of combustion-sustained thermoacoustic instabilities in a modelled swirl combustor. The effects of (1) swirling number SN, (2) inlet air flow rate Va and (3) inlet temperature Ti on the amplitudes and frequencies of swirling combustion-excited limit cycle oscillations are examined. It is found that the amplitude of acoustic fluctuations is increased with increasing SN and Va and decreased with the increase of Ti. The dominant frequency of oscillations is also found to increases with the increase of SN and Va. However, increasing Ti leads to the dominant frequency being decreased first and then increased. An alternative passive control method of installing an adjustable temperature heat exchanger on the combustion chamber wall is then proposed. Numerical results show that thermoacoustic oscillations could be excited and mitigated by setting the heat exchanger temperature to TH. Global and local Rayleigh indexes are applied to further reveal the excitation and attenuation effects on mechanisms. The present study is conducive to developing a simulation platform for thermoacoustic instabilities in swirling combustors. It also provides an alternative method to amplify or mitigate thermoacoustic oscillations.

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Section: Further Investigations Into the Heat Exchanger Temperature T H Effectmentioning

confidence: 99%

Generation and Mitigation Mechanism Studies of Nonlinear Thermoacoustic Instability in a Modelled Swirling Combustor with a Heat Exchanger

2021

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“…The result shows that, there are differences in the combustion stability of various flame structures, and flame structure has a significant effect on the forced flame response. Song et al 29 investigates effects of the corner recirculation zone (CRZ) on flame structures and combustion instabilities. It is found that the penetration of the flame into the CRZ leads to an unstable combustion state, while the stratified flame in the slope confinements combustion chamber shows a stable combustion state.…”

Section: Introductionmentioning

confidence: 99%

Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Zhang

Liu

Zheng

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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The combustion characteristics for a gas turbine (GT) model combustor in air-inlet excitation are studied by Large Eddy Simulation (LES). Time series of heat release rate (HRR) fluctuation is captured during simulation. The precessing vortex core (PVC) structure is shown by pressure iso-surface, and the single/double helix branches of PVC alternately evolve in one forcing cycle. With the rotation of PVC, the high-speed ring zone (HSRZ) is periodically squeezed, and large-scale vortex roll-up results from that. The flame root structure is also significantly affected by PVC, which is one of the reasons for the HRR fluctuation. With the increase of the forcing amplitude, the flame response is divided into three parts. The linear growth zone and secondary rising zone are separated by saturation plateau. The flame dynamics analysis shows that the change of the flame structures and flame front oscillation modes are the apparent mechanism of the nonlinear flame response appearance.

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“…In the case of thermo-acoustic instability [10,11], numerical and experimental methods [12][13][14], experimental flame transfer functions [15,16], large eddy simulations [17,18], fast random particle method [19] and nonlinear network models [20,21] are used. To provide the passive control of thermo-acoustic instability, the slope confinement method is utilized [22]. In addition, the acoustic emission method, which, in recent years, needs less data [23], is used for failure detection in the tubes of steam generators, boilers and heat exchangers [24].…”

Section: Introductionmentioning

confidence: 99%

Performance Identification of a Steam Boiler Burner via Acoustic Analysis

2022

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Almost all systems generate acoustic signals when operating or when a process is being performed. These signals contain certain data related to the operating performance of systems. In this study, acoustic data were used to study the performance and to identify the optimum operating points of natural gas burners that are used in steam boilers. The sound recordings of burners obtained under different operating conditions were examined with acoustic analysis methods. The impact of various operating parameters on acoustic values was determined using time series analysis, frequency spectrum data and then power spectral density values. When the excess air coefficient and emission and efficiency values of boilers were compared with the acoustic data, it was determined that the Yule–Walker algorithm contained distinct and explanatory values. The steam boiler and the natural gas burner within were considered a system for the analysis. Measurement results showed that operating parameters and acoustic analysis results were correlated. Moreover, the results were confirmed with the emission measurement results. Finally, it was deduced that the acoustic values can be used for obtaining the optimum operating points in similar systems where inlet and outlet parameters cannot be measured, and the related principles were revealed.

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The thermoacoustic instability in a stratified swirl burner and its passive control by using a slope confinement

Cited by 20 publications

References 48 publications

Generation and Mitigation Mechanism Studies of Nonlinear Thermoacoustic Instability in a Modelled Swirling Combustor with a Heat Exchanger

Generation and Mitigation Mechanism Studies of Nonlinear Thermoacoustic Instability in a Modelled Swirling Combustor with a Heat Exchanger

Investigation on flame dynamic characteristics to air-inlet excitation in a gas turbine model combustor

Performance Identification of a Steam Boiler Burner via Acoustic Analysis

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