Turbulent collision of inertial particles: Point-particle based, hybrid simulations and beyond

Wang, Lian‐Ping; Rosa, Bogdan; Gao, Hui; He, Guowei; Jin, Guodong

doi:10.1016/j.ijmultiphaseflow.2009.02.012

Cited by 52 publications

(28 citation statements)

References 120 publications

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“…Particularly, turbulence-mediated collision of heavy particles is vital to efficiency and conversion rates in these processes. 5 Large-eddy simulation ͑LES͒ has emerged as a promising tool for simulating turbulent flows in general and, in recent years, has also been applied to particle-laden turbulence with some successes. 6 The motion of heavy particles is much more complicated than fluid elements, and therefore, LES of turbulent flow laden with heavy particles encounters new challenges.…”

Section: Introductionmentioning

confidence: 99%

Large-eddy simulation of turbulent collision of heavy particles in isotropic turbulence

Jin

Wang

2010

Physics of Fluids

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The small-scale motions relevant to the collision of heavy particles represent a general challenge to the conventional large-eddy simulation ͑LES͒ of turbulent particle-laden flows. As a first step toward addressing this challenge, we examine the capability of the LES method with an eddy viscosity subgrid scale ͑SGS͒ model to predict the collision-related statistics such as the particle radial distribution function at contact, the radial relative velocity at contact, and the collision rate for a wide range of particle Stokes numbers. Data from direct numerical simulation ͑DNS͒ are used as a benchmark to evaluate the LES using both a priori and a posteriori tests. It is shown that, without the SGS motions, LES cannot accurately predict the particle-pair statistics for heavy particles with small and intermediate Stokes numbers, and a large relative error in collision rate ͑up to 60%͒ may arise when the particle Stokes number is near St K = 0.5. The errors from the filtering operation and the SGS model are evaluated separately using the filtered-DNS ͑FDNS͒ and LES flow fields. The errors increase with the filter width and have nonmonotonic variations with the particle Stokes numbers. It is concluded that the error due to filtering dominates the overall error in LES for most particle Stokes numbers. It is found that the overall collision rate can be reasonably predicted by both FDNS and LES for St K Ͼ 3. Our analysis suggests that, for St K Ͻ 3, a particle SGS model must include the effects of SGS motions on the turbulent collision of heavy particles. The spectral analysis of the concentration fields of the particles with different Stokes numbers further demonstrates the important effects of the small-scale motions on the preferential concentration of the particles with small Stokes numbers.

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Section: Introductionmentioning

confidence: 99%

Large-eddy simulation of turbulent collision of heavy particles in isotropic turbulence

Jin

Wang

2010

Physics of Fluids

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“…Finally, transfer the moments m * after the above modification back to the distribution functions as [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] where m * means the moment vector after the velocity is constrained. In this procedure, except the velocity, no other macroscopic quantities are changed.…”

Section: The Velocity-constrained Normal Extrapolation Refillingmentioning

confidence: 99%

Lattice Boltzmann simulation of particle-laden turbulent channel flow

et al. 2016

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Highlights• We present the first LBM simulations of particle-laden turbulent channel flows.• The results of single-phase flow are in excellent agreement with benchmark data.• The LBM results of particle-laden flow are similar to finite-difference results.• The presence of particles is shown to significantly alter flow statistics.• The nature of flow modulation depends on spatial location relative to the walls. AbstractModulation of the carrier phase turbulence by finite-size solid particles is relevant to many industrial and environmental applications. Here we report particle-resolved simulations of a turbulent channel flow laden with finite-size solid particles. We discuss how the mesoscopic lattice Boltzmann method (LBM) can be applied to treat both the turbulent carrier flow and moving fluid-particle interfaces. To validate the LBM approach, we first simulate the single-phase turbulent channel flow at a frictional Reynolds number of 180. A non-uniform force field is designed to excite turbulent fluctuations. The resulting mean flow profiles and turbulence statistics were found to be in excellent agreement with the published data based on the Chebychev-spectral method. We also found that the statistics of the fully-developed turbulent channel flow are independent of the setting of some of the relaxation parameters in the LBM approach. We then consider a particle-laden turbulent channel flow under the same body force. The particles have the same density as the fluid. The particle diameter is 5% of the channel width and the average volume fraction is 7.09%. We found that the presence of the particles reduces the mean flow speed by 4.6%, implying that the fluid-particle system is more dissipative than the single-phase flow. The maximum local reduction of the mean flow speed is about 7.5%. The effects of the solid particles on the fluid r.m.s. velocity fluctuations are mixed: both reduction and augmentation are observed depending on the direction and spatial location relative to the channel walls. Overall, particles enhance the relative turbulence intensity in the near wall region and suppress the turbulence intensity in the center region. The particle concentration distribution across the channel is also complicated. We find that there is a dynamic equilibrium location resembling the Segŕe-Silberberg effect known for a laminar wall-bounded flows. Our LBM results were found to be in good agreement with results based on a finite-difference method with direct forcing to handle the moving solid particles. Additionally, phase-partitioned statistics are obtained and compared.

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“…For very small particles, forces including virtual mass force, Basset history force, Saffman force, and Magnus force are negligible as analyzed in our previous work. 23 We have indicated that Brownian motion would lead to considerable collision for fine particles, as described by equation (9) in section ''Collision kernels.'' F D (u 2 v) is the drag force with v being the particle velocity and…”

Section: Particlesmentioning

confidence: 99%

“…Similarly, by including eddy-particle interaction, Zhou et al 11 developed a bidisperse turbulent collision kernel (0.1 \ St \ 5.0). Wang et al 9 recently discussed the collision kernel (0.1 \ St \ 25) using a hybrid direct numerical simulation (HDNS) approach in which the effect of local hydrodynamic interactions of particles is considered. Some reviews on DNS works were summarized by Meyer and Deglon.…”

Section: Inter-particle Collisionmentioning

confidence: 99%

An industry-scale modeling for the turbulence agglomeration of fine particles

Shen

Wang

2015

Advances in Mechanical Engineering

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Turbulence-induced agglomeration of fine particles/droplets in aerosol is important in various industrial and natural processes. Despite abundant theoretical and numerical studies on turbulent collision kernels, convincing numerical methods for industry-scale applications are still lacking. In this work, we develop a mixed Eulerian-Lagrangian model for the modeling of turbulence-induced agglomeration of fine particles/droplets. As advantages over Sommerfeld's model, the present model searches for real collision pairs based on a new mesh-independent method and uses appropriate turbulent collision kernels to calculate the collision frequencies. Benchmark simulations are carried out and compared with the results provided by the well-characterized experiment by Duru et al.

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Turbulent collision of inertial particles: Point-particle based, hybrid simulations and beyond

Cited by 52 publications

References 120 publications

Large-eddy simulation of turbulent collision of heavy particles in isotropic turbulence

Large-eddy simulation of turbulent collision of heavy particles in isotropic turbulence

Lattice Boltzmann simulation of particle-laden turbulent channel flow

An industry-scale modeling for the turbulence agglomeration of fine particles

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