LES investigation of swirl intensity effect on unconfined turbulent swirling premixed flame

Wang, Zhihua; Xu, Yunfeng; Lu, Yilong; Zhou, Zhijun; Zhou, Junhu; Cen, Kefa

doi:10.1007/s11434-014-0507-z

Cited by 3 publications

(2 citation statements)

References 24 publications

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“…The gridscale portion is solved directly whilst the sub-grid-scale portion needs to be modeled using the subgrid closure models [9]. LES has been proven to be competent to capture complex unsteady turbulent flow characteristics, e.g., large-scale vortex structure generation and evolution [10][11][12]. Nambully et al [13] conducted LES of two nonswirling cases of the SwB associated with a filtered-laminar-flame model in combination with a presumed PDF SGS closure.…”

Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Premixed Stratified Swirling Flame Using the Finite Rate Chemistry Approach

Xiao

Lai

Song

2019

International Journal of Aerospace Engineering

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Large eddy simulations of a stratified swirling flow of a Cambridge swirl burner for both nonreacting and reacting cases are conducted using a finite rate chemistry approach represented by a partially stirred reactor model. The large eddy simulation predictions are compared with experimental measurements for velocity, temperature, and concentrations of major species. The agreement is found in overall trend of velocity prediction, but temperature and concentration of major species show slight discrepancies in the central region. Two reduced chemical mechanisms are examined in the present paper with the objective of assessing their capabilities in predicting swirling flame characteristics, and the distinct difference using two mechanisms is found in CO distribution profiles, which is considered the consequence of different kinetics of CO-CO2 equilibrium. Flow structures are qualitatively and quantitatively analyzed with numerical results. Large-scale vortex structures and precession motions are observed in both nonreacting and reacting cases. Frequency of vortex shedding is identified from the point data of instantaneous velocity in the discharging stream-induced shear layer. On this basis, the intensity and frequency of precession motion are shown to be enhanced in the presence of combustion. Large-scale wrinkling of the flame surface is resolved and characterized in the flame zone, and the effect of mixture stratification is then further discussed.

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Section: Introductionmentioning

confidence: 99%

Large Eddy Simulation of Premixed Stratified Swirling Flame Using the Finite Rate Chemistry Approach

Xiao

Lai

Song

2019

International Journal of Aerospace Engineering

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“…LES has been widely accepted as a promising numerical tool for solving the large-scale unsteady behavior of complex turbulent flow [20][21][22][23][24]. Encouraging results have been reported in the recent literatures and demonstrate the capability of LES to account for the generation and evolution of large-scale structures in turbulent swirling flow [25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of unconfined turbulent swirling flow

Zhang

Han

et al. 2015

Sci. China Technol. Sci.

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Large eddy simulations (LES) were performed to study the non-reacting flow fields of a Cambridge swirl burner. The dynamic Smagorinsky eddy viscosity model is used as the sub-grid scale turbulence model. Comparisons of experimental data show that the LES results are capable of predicting mean and root-mean-square velocity profiles. The LES results show that the annular swirling flow has a minor impact on the formation of the bluff-body recirculation zone. The vortex structures near the shear layers, visualized by the iso-surface of Q-criterion, display ring structures in non-swirling flow and helical structures in swirling flow near the burner exit. Spectral analysis was employed to predict the occurrence of flow oscillations induced by vortex shedding and precessing vortex core (PVC). In order to extract accurately the unsteady large-scale structures in swirling flow, a three-dimensional proper orthogonal decomposition (POD) method was developed to reconstruct turbulent fluctuating velocity fields. POD analysis reveals that flow fields contain co-existing helical and toroidal shaped coherent structures. The helical structure associated with the PVC is the most energetic dynamic flow structure. The latter toroidal structure associated with vortex shedding has lower energy content which indicates that it is a secondary structure. Cambridge swirl burner, large eddy simulation, proper orthogonal decomposition, vortex shedding and breakdown, precessing vortex core Citation: Zhang H D, Han C, Ye T H, et al. Large eddy simulation of unconfined turbulent swirling flow.

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Cfd Investigation of the Influence of Swirl Intensity on Co-Firing Characteristics of Biomass/Nh3

Zheng,

Cai,

Zhu

et al. 2023

Preprint

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LES investigation of swirl intensity effect on unconfined turbulent swirling premixed flame

Cited by 3 publications

References 24 publications

Large Eddy Simulation of Premixed Stratified Swirling Flame Using the Finite Rate Chemistry Approach

Large Eddy Simulation of Premixed Stratified Swirling Flame Using the Finite Rate Chemistry Approach

Large eddy simulation of unconfined turbulent swirling flow

Cfd Investigation of the Influence of Swirl Intensity on Co-Firing Characteristics of Biomass/Nh3

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