HAL Id: hal-01772261
https://hal.archives-ouvertes.fr/hal-01772261
Submitted on 20 Apr 2018
HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-entific research documents, whether they are pub-lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
Agglomeration of wet granular materials in rotating drum
Thanh-Trung Vo, Saeid Nezamabadi, Jean-Yves Delenne, Farhang Radjai
To cite this version:
Thanh-Trung Vo, Saeid Nezamabadi, Jean-Yves Delenne, Farhang Radjai. Agglomeration of wet granular materials in rotating drum. Powders & grains 2017, Jul 2017, Montpellier, France. �hal-01772261�
CAPILLARY COHESION & VISCOUS FORCE
INDUSTRIAL PROCESS
MOLECULAR DYNAMICS METHOD
FURTHER RESEARCHES
GRANULE COMPRESSION STRENGTH
AGGLOMERATION RESULTS
OBJECTIVES & METHODOLOGY
AGGLOMERATION OF WET GRANULAR MATERIAL IN ROTATING DRUM
THANH-TRUNG VO , SAEID NEZAMABADI , JEAN-YVES DELENNE , FARHANG RADJAI
1 1 2 1,3Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, Montpellier, France IATE, UMR1208 INRA - CIRAD - Université de Montpellier - SupAgro, 34060 Montpellier, France
<MSE>, UMI 3466 CNRS-MIT, CEE, MIT, 77 Massachusetts Avenue, Cambridge 02139, USA
1
2 3
position vector of particle i
mass of particle i (kg) vector gravity
normal unit vector
tangential unit vector
Simulation the agglomeration process of solid particles in the presence of a viscous liquid. We are mostly interested in application to iron ore granulation in a horizontal rotating drum. In this work, we use Molecular Dynamics (MD) method to simulate the agglomeration process during the dense granular flows in the rotary drum. In which particles are distributed by an uniform distribution of particle volume fractions.
Granulation (balling) Drum
Agglomeration is the process of particles size enlargement and most commonly refers to the upgrading of material fines into larger particles, such as pellets or granules. Iron ore granulation is an important stage in the steel making.
ROLLING - CASCADING MODEL
Water drops Dry particles Wet particles Granule
)
rota ting dru m capillary bondMechanism of granule formation
Granular material flow & granule growth in the cascading regime
8
thInternational Conference on
Micromechanics of Granular Media
Exponential increase of granule for different Froude numbers. Exponential increase of granule
for different size ratios
Exponential increase of kinetic energy normalized by potential energy
of granule as function of Fr.
Exponential increases of wet & contact coordination numbers (a) and decrease of kinetic energy normalized by potential energy of granule (b), as functions of size ratio 𝞪.
a) b)
Filling level: Packing fraction:
- Investigation the agglomeration process of a huge number of particles.
- Comparison between experiment and simulation of agglomeration processes in rotating drum.
Conclusions
1 The effect of size ratio on the granule
growth is more crucial than that of rotational speed.
2 Granule growth is an exponential function
of size ratio and rotational speed of drum.
3 Kinetic energy normalized by potential
energy increases proportional to the rotational speed, but inversely proportional to the size ratio.
4 The wet and contact coordination
numbers of agglomerate grains are proportional to size ratio.
-4.5 -4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0 5x10-7 1x10-6 1.5x10-6 2x10-6 2.5x10-6 3x10-6 3.5x10-6 4x10-6 f c (10 -6 N) δn (m) Vb=1.7 10-17(m3), α=2 Vb=7.1.10-18(m3), α=2 Vb=1.7 10-17(m3), α=3 Vb=7.1.10-18(m3), α=3 Vb=1.7 10-17(m3), α=4 Vb=7.1.10-18(m3), α=4 Vb=1.7 10-17(m3), α=5 Vb=7.1.10-18(m3), α=5 Froude number:
Powders & Grains 2017
Granule
(formed & grown)
!
!
0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 kΕ g /p Ε g α 0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 kΕ g /p Ε g α 0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 kΕ g /p Ε g α 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number Ζ c , Ζ b α Ζb Ζc 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number Ζ c , Ζ b α Ζb Ζc 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number Ζ c , Ζ b α Ζb Ζc 0.29 0.295 0.3 0.305 0.31 0.315 0.5 0.6 0.7 0.8 0.9 1 kΕ g /p Ε g Fr 0.29 0.295 0.3 0.305 0.31 0.315 0.5 0.6 0.7 0.8 0.9 1 kΕ g /p Ε g Fr 0.29 0.295 0.3 0.305 0.31 0.315 0.5 0.6 0.7 0.8 0.9 1 kΕ g /p Ε g Fr 100 110 120 130 140 150 160 170 180 190 200 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions Fr=0.5 Fr=0.6 Fr=0.7 Fr=0.8 Fr=0.9 Fr=1.0 100 110 120 130 140 150 160 170 180 190 200 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions Fr=0.5 Fr=0.6 Fr=0.7 Fr=0.8 Fr=0.9 Fr=1.0 100 110 120 130 140 150 160 170 180 190 200 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions Fr=0.5 Fr=0.6 Fr=0.7 Fr=0.8 Fr=0.9 Fr=1.0m
id
2s
idt
2=
X
(i)((f
n+ f
c+ f
vis)n + f
tt) + m
ig
s
i
g
n
t
m
i Liquid bridge Ri i mig fcij f ij n fvisij fvisik fcik ftij mkg k Rk Rj j mjg n!
A
B'
!
S
LCC
R
c x zf =
S
⇡R
2c=
'
sin '
2⇡
= Vs S ⇤ L = ⌃( 43 ⇡R3i ) S ⇤ L F r = ! 2R c gC = AB = 2R
csin
'
2
S =
R
2 c2
('
sin ')
LC = AB = 'Rc fc = 8 > < > : R, for n < 0Re n , for 0 n nmax
0, for n nmax fvis = 3 2 ⇡R 2⌘ 1 n d n dt
= 2⇡
scos ✓
max n = (1 + 1 2 ✓)V 1/3 b ↵ = Rmax Rmin = c h(↵)( Vb R0 ) 1 2R =
p
R
iR
j Diagram of capillary bridgefracture dg
The snapshots of model and force chains of a granule under diametrical compression.
0.2 0.4 0.6 0.8 1 1.2 0 0.2 0.4 0.6 0.8 1 σ p /σ c µ α = 1 α = 2 α = 5 0.2 0.4 0.6 0.8 1 1.2 0 0.2 0.4 0.6 0.8 1 σ p /σ c µ α = 1 α = 2 α = 5 0.2 0.4 0.6 0.8 1 1.2 0 0.2 0.4 0.6 0.8 1 σ p /σ c µ α = 1 α = 2 α = 5 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0 1 2 3 4 5 6 Φ α 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0 1 2 3 4 5 6 Φ α 0.4 0.45 0.5 0.55 0.6 0.65 0.7 0 1 2 3 4 5 6 Φ α 8 9 10 11 12 13 0 1 2 3 4 5 6 Ζ α 8 9 10 11 12 13 0 1 2 3 4 5 6 Ζ α 8 9 10 11 12 13 0 1 2 3 4 5 6 Ζ α
Normalized peak strength as
function of friction coefficient. Packing fraction and coordination number, as functions of size ratio
c = s
hRi
!
Rotational speed (rad/s)Free surface angle Filling angle (degree)