Turbulence intensity in dilute two-phase flows—3 The particles-turbulence interaction in dilute two-phase flow

Yarin, L. P.; Hetsroni, G.

doi:10.1016/0301-9322(94)90004-3

Cited by 116 publications

(30 citation statements)

References 26 publications

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“…Another quantitative estimation of the influence of particles on turbulence was proposed by Yarin and Hetsroni [4] who evaluated two sources of turbulence in two-phase flows. On the one hand, they applied the mixing length theory for calculation of turbulence due to velocity gradients in wallbounded flows and, on the other hand, derived a turbulent kinetic energy balance determining the turbulence modulation due to vortex shedding behind particles.…”

Section: Introductionmentioning

confidence: 99%

Influence of Particles on Fluid Turbulence in Pipe and Diffuser Gas‐Solids Flow

Bohnet¹,

Triesch²

2003

Chem Eng & Technol

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The influence of glass particles with different Reynolds numbers Re P = ½u±u P ½d P r/g on axial and radial gas fluctuations as well as on Reynolds stresses was investigated for pipe and diffuser (continuous pipe expansion) gas-solids flow. Measurements were carried out using phase-Doppler anemometry distinguishing between velocity signals of the solid and fluid phase due to particle or tracer size. In fully developed pipe flow small particles (Re P = 60) damp turbulence but with increasing Re P vortex shedding behind the particles reduces attenuation and finally leads to turbulence enhancement. Behind the diffuser particles are decelerated and cause a steeper velocity gradient and, thus, an increase in turbulence. The measured data are compared to CFD calculations investigating Reynolds stress model and k-e model for the description of turbulence. Using small particles good agreement is achieved considering the momentum transfer between the phases. For larger particles the modeling of vortex shedding by turbulent particle source terms is needed for a satisfactory prediction.

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Section: Introductionmentioning

confidence: 99%

Influence of Particles on Fluid Turbulence in Pipe and Diffuser Gas‐Solids Flow

Bohnet¹,

Triesch²

2003

Chem Eng & Technol

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“…However, Hardalupas et al (1989) proved experimentally that particles without wakes (small Re p ) can also increase the production of the turbulent energy. Yarin and Hetsroni (1994) showed that the ratio of the particle diameter to the turbulence scale does not generalize the experimental data for all flows laden with particles of different sizes. Additionally, the experimental work of Noguchi and Nezu (2009) showed that the particle-fluid interaction is governed by the Kolmogorov microscale rather than the macroscale such as the integral scale in sediment-laden flows.…”

Section: Overview Of the Modulation Of The Particles On The Fluid Turmentioning

confidence: 97%

Effect of particle clusters on turbulence modulations in liquid flow laden with fine solid particles

Pang

Wei

2011

Braz. J. Chem. Eng.

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-Studies on particle distributions and interactions between the particles and the liquid turbulence are extremely significant and can help to improve efficiency of industrial processes and final product quality. In this paper, the particle distribution and the particle-turbulence interaction in the solid-liquid flow were investigated in detail by a numerical method. The governing equations of the liquid were solved by direct numerical simulations and the particle was tracked by Newtonian motion equations considering the effects of drag force, lift force, pressure gradient force, and virtual mass force. Two-way coupling was used to explain the effect of the particles on the turbulence. The results showed that the vortex has a great influence on the particle distribution. Most of the particles aggregate at the centre of the channel. Particle clusters along the vortex circumference modulate the development of the vortex. The turbulence modulations showed anisotropy. The Reynolds stress is slightly reduced in a broad range; the energy balance is changed; and an extra term is introduced to maintain a new energy balance.

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“…These four parameters may be expressed as 1) mass /volumetric solid loading, 2) the ratio of particle diameter to the fluid turbulence length scale 3) particle Reynolds number ( = ( − ) ⁄ ) and 4) Stokes number ( = ⁄ ) (Fokeer, et al, 2004;Gouesbet & Berlemont, 1998;Mandø, 2009;Yarin & Hetsroni, 1994) where is the fluid density, is the fluid velocity, is the particle velocity, is particle diameter and is the dynamic viscosity. and are particle response time and eddy turnover time respectively.…”

Section: Turbulence Modulation In Fluid-particle Flowsmentioning

confidence: 99%

CFD–DEM simulation of turbulence modulation in horizontal pneumatic conveying

Ebrahimi

Crapper

2017

Particuology

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A study is presented to evaluate the capabilities of the standard k-turbulence model and the k-turbulence model with added source terms in predicting the experimentally measured turbulence modulation due to the presence of particles in horizontal pneumatic conveying, in the context of a CFD-DEM Eulerian-Langrangian simulation. Experiments were performed using a 6.5 m long, 0.075 m diameter horizontal pipe in conjunction with a laser Doppler anemometry (LDA) system. Spherical glass beads with two different sizes, 1.5 mm and 2 mm, were used. Simulations were carried out using the commercial Discrete Element Method (DEM) software EDEM, coupled with the Computational Fluid Dynamics (CFD) package FLUENT. Hybrid source terms were added to the conventional k- turbulence model to take into account the influence of the dispersed phase on the carrier phase turbulence intensity. The simulation results showed that the turbulence modulation depends strongly on the model parameter Cɛ3. Both the standard k- turbulence model and the k- turbulence model with the hybrid source terms could predict the gas phase turbulence intensity trend only generally, with in all cases a noticeable discrepancy between simulation and experimental results was observed, particularly for the regions close to the pipe wall. It was also observed that in some cases the addition of the source terms to the k- turbulence model did not improve the simulation results when compared to the simulation results of the standard k- turbulence model, though in the lower part of the pipe where particle loading was greater due to gravitational effects the model with added source terms performed somewhat better.

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Turbulence intensity in dilute two-phase flows—3 The particles-turbulence interaction in dilute two-phase flow

Cited by 116 publications

References 26 publications

Influence of Particles on Fluid Turbulence in Pipe and Diffuser Gas‐Solids Flow

Influence of Particles on Fluid Turbulence in Pipe and Diffuser Gas‐Solids Flow

Effect of particle clusters on turbulence modulations in liquid flow laden with fine solid particles

CFD–DEM simulation of turbulence modulation in horizontal pneumatic conveying

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