Numerical predictions of flow behavior and cluster size of particles in riser with particle rotation model and cluster-based approach

Wang, Shuyan; Shen, Zhiheng; Huilin, Lu; Yu, Liang; Wentie, Liu; Ding, Yonlong

doi:10.1016/j.ces.2008.05.021

Cited by 38 publications

(11 citation statements)

References 41 publications

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“…Possible mechanics for the formation of particle clusters include hydrodynamic interactions (drag minimization) (Geldart, 1987;Zelenko et al, 1996) , inelastic grain-grain collision (collisional cooling (Lu et al, 2005;Wang et al, 2009) and viscous dissipation (Subbarao, 1986;Shuyan et al, 2008)), electrostatic forces, capillary bridging or van der Waals forces (Israelachvili, 1992;Podczeck, 1998;Visser, 1989). Royer et al (2009) investigated some of these effects in granular streams of particles freely falling from a small opening at the bottom of a hopper.…”

Section: Clusters and Cohesive Forcesmentioning

confidence: 99%

Small-Scale Particle Interactions Are Having Significant Effects on Global Fluidized Bed Behavior

Cocco

Issangya

Karri

et al. 2017

KONA

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Fluidized bed design and scale-up depends strongly on particle characteristics such as size, shape, and for Geldart Group A particles, the level of fines (particles smaller than 44 microns). However, recent research has shown that particle clustering has a significant effect on fluidized bed hydrodynamics which impacts how these units should be designed and scaled up. This is especially true with the estimation of the solids entrainment rate and the cyclone collection efficiency. The amount of fines, particle shape and surface morphology play a role on the level of particle clustering in a fluidized bed. The fine particles are an excellent conduit for moving charge as electrons or ions which appear to be the dominant mechanism of electrostatics for Geldart Group A material in a bubbling fluidized bed. This electrostatic force trades off with particle momentum relaxation and rotational to translation momentum transfer with regard to forming a particle cluster. The issue is the quantification of this effect so more precise calculations can be made with particle entrainment rates and cyclone collection efficiency. Preliminary work on particle shear in a packed and fluidized beds, suggest that particle clustering can be measured and may provide a quantifiable metric for the level of particle clustering.

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Section: Clusters and Cohesive Forcesmentioning

confidence: 99%

Small-Scale Particle Interactions Are Having Significant Effects on Global Fluidized Bed Behavior

Cocco

Issangya

Karri

et al. 2017

KONA

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“…By solving the rotational granular temperature in an explicit way, Jenkins and Zhang derived an effective coefficient of restitution for the original KTGF. In recent years, this effective coefficient approach has been successfully applied to simulate dense gas–solid flows …”

Section: Introductionmentioning

confidence: 99%

Boundary conditions for collisional granular flows of frictional and rotational particles at flat walls

Zhao

Zhong

et al. 2014

AIChE Journal

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in Wiley Online Library (wileyonlinelibrary.com) Collisions between frictional particles and flat walls are determined using Coulomb friction and both tangential and normal restitution, and pseudothermal states of particles are described by both the translational and rotational granular temperatures. Then, new models for the stresses and the fluxes of fluctuation energy for the collisional granular flows at the walls are derived. These new models are tested and compared with the literature data and models. The ratio of rotational to translational granular temperatures is shown to be crucial on accurately predicting the shear stress and energy flux and is dependent on the normalized slip velocity as well as the collisional parameters. Using a theoretical but constant value for this ratio, predictions by the new models could still agree better with the literature data than those by the previous models. Finally, boundary conditions are developed to be used within the framework of kinetic theory of granular flow. V C 2014 American Institute of Chemical Engineers AIChE J, 60: 4065-4075, 2014 Figure 4. Stress ratio over normalized slip velocity for different coefficients of normal restitution. (The lines and symbol have the same meaning as in Figure 3. Besides, red dashed line ---: present model with specified k. Inset: red dashed line ---: specified k.) [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.] 4070

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“…They found that the model captures the bubble dynamics and time-averaged bed behavior. Shuyan et al 35 simulated flow behavior of particles in the bubbling fluidized bed based on the kinetic theory for flow of dense, slightly inelastic, slightly rough sphere proposed by Lun 30 to account for rough sphere binary collisions and the frictional stress model proposed by Johnson et al 36 to consider the frictional contact forces between particles. By setting the rotational energy dissipation rate to zero in a steady, homogeneous shear flow, the ratio of the rotational granular temperature to the translational granular temperature is correlated with the roughness coefficient of particles.…”

Section: Introductionmentioning

confidence: 99%

A bubbling fluidization model using kinetic theory of rough spheres

et al. 2011

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in Wiley Online Library (wileyonlinelibrary.com).Collisional motion of inelastic rough spheres is analyzed on the basis of the kinetic theory for flow of dense, slightly inelastic, slightly rough sphere with the consideration of gas-solid interactions. The fluctuation kinetic energy of particles is introduced to characterize the random motion of particles as a measure of the translational and rotational velocities fluctuations. The kinetic energy transport equation is proposed with the consideration of the redistribution of particle kinetic energy between the rotational and translational modes and kinetic energy dissipation by collisions. The solid pressure and viscosity are obtained in terms of the particle roughness and restitution coefficient. The partition of the random-motion kinetic energy of inelastic rough particles between rotational and translational modes is shown to be strongly affected by the particle restitution coefficient and roughness. Hydrodynamics of gas-solid bubbling fluidized beds are numerically simulated on the basis of the kinetic theory for flow of rough spheres. Computed profiles of particles are in agreement with the experimental measurements in a bubbling fluidized bed. The effect of roughness on the distribution of energy dissipation, kinetic energy, and viscosity of particles is analyzed. V V C 2011 American Institute of Chemical Engineers AIChE J, 58: [440][441][442][443][444][445][446][447][448][449][450][451][452][453][454][455] 2012

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Numerical predictions of flow behavior and cluster size of particles in riser with particle rotation model and cluster-based approach

Cited by 38 publications

References 41 publications

Small-Scale Particle Interactions Are Having Significant Effects on Global Fluidized Bed Behavior

Small-Scale Particle Interactions Are Having Significant Effects on Global Fluidized Bed Behavior

Boundary conditions for collisional granular flows of frictional and rotational particles at flat walls

A bubbling fluidization model using kinetic theory of rough spheres

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