Agglomeration Process of Wet Granular Material: Effects of Size Distribution and Froude Number

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Agglomeration Process of Wet Granular Material:

Effects of Size Distribution and Froude Number

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 Process of

Wet Granular Material: Effects of Size Distribution and Froude Number. 28th ALERT Workshop,

Oct 2017, Aussois, France. 2017. �hal-01772410�

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CAPILLARY COHESION & VISCOUS FORCE

INDUSTRIAL PROCESS MOLECULAR DYNAMICS METHOD

FURTHER RESEARCHES AGGLOMERATION RESULTS OBJECTIVES & METHODOLOGY

Agglomeration Process of Wet Granular Material: Effects of

Size Distribution and Froude Number

THANH-TRUNG VO , SAEID NEZAMABADI , JEAN-YVES DELENNE , FARHANG RADJAI1,2 1 3 1,4

position vector of particle i

mass of particle i (kg) vector gravity normal unit vector tangential unit vector

We investigate 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 bond

Mechanism of granule formation

Granular material flow & granule growth in the cascading regime

28

th

_{ALERT Workshop}

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

p o t e n t i a l e n e r g y i n c r e a s e s 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 fc (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:

Aussois 2017

Granule (form & grow)

!

0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 k g /p g 0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 k g /p g 0.27 0.275 0.28 0.285 0.29 0.295 0.3 2 2.5 3 3.5 4 4.5 5 k g /p g 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number c , b b c 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number c , b b c 3 4 5 6 7 8 9 10 11 12 2 2.5 3 3.5 4 4.5 5 Coordination number c , b b c 0.29 0.295 0.3 0.305 0.31 0.315 0.5 0.6 0.7 0.8 0.9 1 k g /p 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 k g /p 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 k g /p 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=1.0 mid 2_s i dt2 = X (i) ((fn+ fc+ fvis)n + ftt) + mig

s

i

g

n

t

mi

!

A B '

!

S LC C Rc x z f = S ⇡R2 c =' sin ' 2⇡ = Vs S⇤ L= ⌃(4 3⇡R 3 i) S⇤ L F r =! 2_R c g C = AB = 2Rcsin ' 2 S =R 2 c 2(' sin ') LC = AB = 'Rc fc= 8 > < > : R, for n< 0 Re n , for 0 n nmax 0, for n maxn fvis= 3 2⇡R 2_⌘1 n dn dt

 = 2⇡

s

cos ✓

max n = (1 + 1 2✓)V 1/3 b ↵ =Rmax Rmin = c h(↵)(Vb R0) 1 2 R =pRiRj Diagram of capillary bridge

!

Rotational speed (rad/s) Free surface angle Filling angle (degree)

'

debonding distance 100 120 140 160 180 200 220 240 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions 100 120 140 160 180 200 220 240 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions =2 =3 =4 =5 100 120 140 160 180 200 220 240 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions 100 120 140 160 180 200 220 240 0 10 20 30 40 50 Granule growth, N g (particles) Drum Revolutions

Laboratoire de Mécanique et Génie Civil (LMGC), Université de Montpellier, CNRS, Montpellier, France. Bridge and Road Department, Danang Architecture University, 566 Nui Thanh St, Hai Chau Dist, Danang, Vietnam.

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 4 Liquid bridge Ri i mig fij c fij n fij vis fik vis fik c fij t mkg k Rk Rj j mjg n