Mechanisms and kinetics of gravity separation of granular materials

Dolgunin, V. N.; Kudi, A. N.; Tuev, M. A.

doi:10.3367/ufne.2020.01.038729

Cited by 5 publications

(15 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Obviously, under this condition, dynamic equilibrium in the flow will be achieved in the boundary zone due to an increase in the shear rate and a decrease in the volume fraction of the solid phase, which is confirmed by the results of experimental studies [2,3,25,26].…”

Section: Discussionsupporting

confidence: 64%

“…The contribution of transverse mass transfer to generating shear stresses in the rapid gravity flow of incoherent nonelastic nonsmooth spherical particles can be estimated based on the formal analogy of the rapid shear flow of particles with a dense gas. The existence of the analogy is confirmed by numerous studies [1,2,4,11,[12][13][14]24], which made it possible to identify a granular medium in a state of rapid shear deformation as a "gas of solid particles" and successfully apply a well-developed molecular kinetic theory to describe its states and observed physical effects [4].…”

Section: Resultsmentioning

confidence: 93%

“…One of the main objects studied in physics of soft condensed matter is granular media [1,2]. Such attention to granular materials is explained not only by the global nature of their distribution in the environment and technological processes, but also their pronounced mesoscopic properties.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Transversal mass transfer and shear stress formation during rapid gravity flow of a granular medium

Dolgunin

Иванов²,

Akopyan

2021

JAMT

View full text Add to dashboard Cite

The micro structural models for shear stress generation during rapid gravity flow of granular materials on a rough chute are discussed. The mechanism of the shear stress formation, taking into account the tangential impulse formed under transversal mass transfer of particles, is suggested. The analogy between granular media during rapid shear deformation and dense gases is used to develop the suggested mechanism on the basis of kinetic theory. The total shear stress is determined as the sum of the stress components induced by collisions, transversal mass transfer and contact interactions of uniform cohesionless inelastic spherical particles. The mathematical models describing the components of shear kinetic stresses are developed as the functions of particle properties, structural and kinematical gravity flow characteristics. The equations of impulse and energy conservation in the course of rapid gravity flow of uniform cohesionless particles are formulated. A variant of the formulation of boundary conditions at the flow bottom is proposed for mathematical modeling of the dynamics of rapid gravity flows of granular materials on a rough chute. The variant assumes the displacement of the area with the most intense shear rate inside the flow and into its layers adjacent to the rough chute surface.

show abstract

Section: Discussionsupporting

confidence: 64%

Section: Resultsmentioning

confidence: 93%

See 1 more Smart Citation

Transversal mass transfer and shear stress formation during rapid gravity flow of a granular medium

Dolgunin

Иванов²,

Akopyan

2021

JAMT

View full text Add to dashboard Cite

show abstract

“…Under conditions of fast gravity flow the exchange of particles by shock impulses is accompanied by dilatancy of granular medium, the degree of which depends on shear rate and lithostatic pressure value [7][8][9]. As a result, in a fast gravity flow there is a high inhomogeneity of shear rate and void volume fraction by bed height, which is especially pronounced in a thin-bed flow.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and kinetics of separation of impurity particles with different densities in a rapid gravity flow of granular material

Ivanov,

Dolgunin,

Tarakanov

et al. 2023

JAMT

View full text Add to dashboard Cite

The efficiency of the separation process of impurity particles with different densities in a rapid gravity flow of monodisperse granular material has been studied. The study was carried out by mathematical modeling of particle concentration distribution dynamics on a rough chute using a mathematical model that takes into account the kinetics of convection, mixing, segregation and quasi-diffusion separation effects. During the research process, the relative density of impurity particles in the range of 0.2-4.0 was varied with respect to the base component particle density, and this confirms the defining role of the quasi-diffusive separation effect. It was found that the concentration distribution profiles of lowand high-density particles have a shape similar to the shape of the profiles of the volume fractions of voids and solids, respectively. With the same degree of difference between the light and heavy impurity particles from the base component particles, the light particles have a higher tendency to separate. The tendency to separation with increasing degree of difference between the density of the impurity particles and the density of the base component particles increases more intensively for the impurity particles with low density. It is found that with decreasing concentration of impurity particles in the flow, the intensity of their separation increases for particles with low density and decreases for particles with high density. A binary mixture of homogeneous particles with the minimum volume content of low density particles is characterized by the highest tendency to particle density separation.

show abstract

“…In recent years, the granular matter has become one of the hotspots in condensed matter physics research, and related research has important scientific significance and engineering application value [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Separation behaviour of polypropylene mixed particles under the coupling of vibration and airflow

Zhao¹,

Ma²

2022

Phys. Scr.

View full text Add to dashboard Cite

Granular matter is a disordered system composed of a large number of particles, which appears as a complex physical phenomenon under external excitation. To study the separation behaviour of polypropylene particles, the separation of particles under various excitation methods was simulated based on the DEM-CFD coupling method. The results showed that polypropylene particles did not show Reverse Brazil Nut Separation under the single excitation of either vertical vibration or pulsed airflow, while under the double excitation of vertical vibration and constant airflow, the large particles located in the upper layer of small particles started to sink and formed Reverse Brazil Nut Separation. By analysing the change of voidage in particle bed, the explanation of the change of particle separation state by filling theory is verified. The airflow velocity increased from 15 m/s to 21 m/s, and the volume concentration of large particles at the bottom increased by 27.615%, which promoted the formation of Reverse Brazil Nut Separation. The frequency and amplitude increased to 15 Hz, 20 mm or decreased to 5 Hz, 5 mm, respectively, and the volume concentration of large particles at the bottom decreased by 22.025%, 23.807% and 46.712%, 59.003%, indicating that too large or too small vibration acceleration would inhibit the formation of Reverse Brazil Nut Separation. In addition, changing the shape of the container or increasing the filling rate of particles in the container can eliminate the phenomenon of small particles accumulating in the corner.

show abstract

Mechanisms and kinetics of gravity separation of granular materials

Cited by 5 publications

References 57 publications

Transversal mass transfer and shear stress formation during rapid gravity flow of a granular medium

Transversal mass transfer and shear stress formation during rapid gravity flow of a granular medium

Mechanism and kinetics of separation of impurity particles with different densities in a rapid gravity flow of granular material

Separation behaviour of polypropylene mixed particles under the coupling of vibration and airflow

Contact Info

Product

Resources

About