Numerical simulation of turbulent swirling gas-dispersed flow behind a sudden tube expansion

Пахомов, М. А.; Терехов, В. И.

doi:10.1134/s086986431505008x

Cited by 12 publications

(9 citation statements)

References 27 publications

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“…It was attenuated with increasing particle size and mass loadings . Swirling two-phase hydrodynamics using PDPA were also performed. , In recent years, the direct numerical simulation (DNS), − the large eddy simulation (LES), and − the Reynolds averaged Navier–Stokes simulation (RANS) − have been rapidly applied to model and simulate the hydrodynamics of two-phase flows based on the computational fluid dynamics (CFD) technique. The definition of gas turbulence modulation in particle-laden flows can be expressed by the effects of the relevant particle size, density, and volume fraction on flow information as well as the particle Stokes number even if it has been not well understood so far.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

2021

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Turbulence modulations by particles of a swirling gas–particle two-phase flow in an axisymmetric chamber are numerically simulated. To fully consider the preferential concentrations and the anisotropic dispersions of particles, a second-order moment model coupling particle–particle collision model was improved. Experimental validation for the proposed model, algorithm, and in-house codes by acceptable match was carried out. The effects of ultralight-expanded graphite and heavy copper particles with a large span of Stokes number on gas velocities and fluctuations, Reynolds shear stresses and tensor invariants, turbulence kinetic energies, and vortice structures are investigated. The results show that turbulent modulation exhibits strong anisotropic characteristics and remains in a close relationship with the flow structure. Modulation disturbances and vortex evolution are enforced by heavy-large particles with higher Stokes numbers. Preferential accumulations of ultralight particles in shear stress regions at lower vortices are weaker than those of heavy particles. For axial turbulence modulations, a heavy particle plays the primary role in the inhibition action because of larger inertia, and a light particle contributes to the enhancement effect due to excellent followability. The instantaneous flow information and coherent turbulent structure are failed to be acquired due to the limitation of the Reynolds time-averaged algorithm.

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Section: Introductionmentioning

confidence: 99%

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

2021

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“…In recent years, computational fluid dynamics (CFD) methods are being utilized substantially compared to hydrodynamic modelling for the single/multicomponent gas-particle two-phase turbulent flow, e.g., the direct numerical simulation (DNS) algorithm [6][7][8][9][10][11], large eddy simulation (LES) SGS model [12][13][14][15][16][17][18], and Reynolds time-averaged Navier-Stokes simulation (RANS) [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. Regarding gas turbulence modulations, Gore et al (1989) [35] found that turbulence modifications generally have two kind of effects-that is, the augmentation and attenuation activities-using a dimensionless parameter based on the ratio of particle diameter and length of maximum eddy.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the turbulence attenuation phenomenon was found by means of the dimensionless Reynolds-particle momentum numbers proposed by Tanaka et al (2008) [23]. Pakhomov et al (2015) [24] proposed a Reynolds stresses model for gas-particle turbulence flow and revealed that gas turbulent modulation can be attenuated by fine particles, reaching up to 25% for swirling particle dispersions. As for the particle dispersions of swirling gas-particle two-phase flow in a combustor, the isotropic or homogeneous particle dispersion characteristics were denoted by references [13,14,21,24] and isotropic dispersions by references [4,5,[29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

Investigations of Gas–Particle Two-Phase Flow in Swirling Combustor by the Particle Stokes Numbers

Liu

2021

Processes

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Gas turbulence modulations and particle dispersions of swirling gas–particle two-phase flow in the combustor is investigated under the large spans of the particle Stokes numbers. To fully consider the preferential concentrations and anisotropic dispersions of a particle, a kinetic frictional stress model coupled with a second-order moment two-phase turbulent model and granular temperature equation is improved. The proposed modeling and simulations are in good agreement with the experimental validations. Results show turbulent modulations and particle dispersions exhibit strongly anisotropic characteristics, keeping a close relationship with flow structure. The axial gas velocity and RMS fluctuation velocity of 45.0-μm EGP was approximately 5.0 times and 3.0 times greater than 1000.0 μm Copper particles, and their axial particle velocity was 0.25 times and twice greater than those of 45.0 μm EGP. The degree of modulation in the axial–radial direction is larger than those of radial–tangential and axial–tangential direction. Particle dispersions are sensitive to particle diameter parameters and intensified by higher Stokes number.

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“…Swirling two-phase hydrodynamics using PDPA were performed by Sommerfield et al 1991,1993 [12,13] . In recent years, the direct numerical simulation (DNS) [18][19][20][21][22][23] , the large eddy simulation (LES) [24][25][26][27][28][29][30][31] , the Reynolds averaged Navier-Stokes simulation (RANS) [32][33][34][35][36][37][38][39][40][41] , have been applied to model and simulate the hydrodynamics of two-phase flows has been rapidly developed based on the computational fluid dynamics (CFD) technique. Gore et al1989 [42] characterized the turbulence modification into augmentation and attenuation categories using a developed intuitive parameter, which is the ratio of the particle diameter to a characteristic size of large eddies.…”

Section: Introductionmentioning

confidence: 99%

“…The turbulence attenuation was observed between the augmentation regions with two critical particle momentum numbers according to 6 the mapped of Re-Pa numbers. Lin et al 2014 [36] developed a probability density function to describe the cylindrical particle orientation. He found that turbulence intensity enhancement caused by cylindrical particles is smaller in the streamwise than that of near the nozzle exit, as well as directly proportional to particle concentration, Reynolds number and particle aspect ratio.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamic Modeling of Turbulence Modulation by Particles in Swirling Gas-Particle Two-Phase Flow

Liu

Zhou

2021

Preprint

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Turbulence modulations by particles of swirling gas-particle two-phase flow the axisymmetric chamber is investigated. To fully consider the preferential concentrations and anisotropic dispersions of particle, a second-order moment model coupling particle-particle collision model was improved based on the Eulerian-Eulerian two-fluid approach and the kinetic theory of granular flow. Proposed model, algorithm and in-house codes are validated and they are in good agreement with the experiment. Effects of ultralight expanded graphite and heavy Copper particles with large spans of Stokes number on gas velocity and fluctuations, Reynolds shear stress and tensor invariants, turbulence kinetic energy, and vortices structures are numerically simulated. Results show turbulent modulation exhibits strongly anisotropic characteristics and keeps in close relationship with flow structure. The disturbances of modulations, the alternations of vortex evolution are enforced by heavy-large particle with higher Stokes numbers. Preferential accumulations of light particle at shear stress regions in low vortices are weaker than those of heavy particle. For axial turbulence modulations, heavy particle plays the primary role on inhibition action due to larger inertia and light particle contributes to enhancement effect due to excellent followability.

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Numerical simulation of turbulent swirling gas-dispersed flow behind a sudden tube expansion

Cited by 12 publications

References 27 publications

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

Hydrodynamic Modeling of Turbulence Modulation by Particles in a Swirling Gas–Particle Two-Phase Flow

Investigations of Gas–Particle Two-Phase Flow in Swirling Combustor by the Particle Stokes Numbers

Hydrodynamic Modeling of Turbulence Modulation by Particles in Swirling Gas-Particle Two-Phase Flow

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