UBC Mechanical Engineering CFD Modeling Group

Dr. Martha SalcudeanWeyerhaeuser Industrial Research ChairFellow C.S.M.E., F.C.A.A., F.R.S.C.

Dr. Ian GartshoreFellow C.A.S.I.

FLUID - FIBER INTERACTION IN HYDRO-CYCLONES

FUNDINGFUNDING

- FRBC- Network for Mechanical Pulping- Weyerhaeuser Paper Company

Zhengbing Bian Paul Nowak

Eric Bibeau Mohammad Shariati

Suqin Dong Emil Statie

Xioasi Feng David Stropky

Mike Georgallis Zhu Zhi Xiao

Pingfan He Jerry Yuan

Lu Hua Kegang Zhang

OBJECTIVES

• Compute 3D flow in hydro-cyclones

• Improve mathematical models of swirling flows

• Develop mathematical models to compute fiber trajectories in complex flows

• Model separation and fractionation according to fiber properties in hydro-cyclones

MODEL• Modified k- model for highly curved turbulent flows

• Finite volume discretization using a generalized curvilinear system

• Particle tracking through explicit time marching based on force balance

END-USERS

• Pulp mills requiring high efficiency for fiber cleaning and fractionation

• Hydro-cyclone manufacturers

• Increase operating efficiency for hydro-cyclones

• Optimize the hydro-cyclones design

• Evaluate the influence on fractionation of fiber wet density, fiber diameter, fiber length, and fiber specific surface

• Evaluate the influence of the fluid temperature on fractionation

• Predict the fractionation performance of a hydro-cyclone for given fiber properties

diameter (microns)

carriedover(%)

10

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0 0

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A diameterB diameter

Fiber A

*

*

Fiber B

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0

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carriedover(%)

5

0

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carrie

dover(%)

5

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cov89.62577.67565.72553.77541.82529.87517.9255.975

densityrel = 1.04

densityrel = 1.14

densityrel = 1.4220

40

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0

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carriedover(%)

1.2

1.4

0

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carrie

dover(%)

1.2

1.4

20

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cov22.220.385718.571416.757114.942913.128611.31439.57.685715.871434.057142.242860.428571-1.38571-3.2

10 20 30 40 50 60 70

diameter (microns)

10 20 30 40 50 60 70

diameter (microns)

1.1

1.2

1.3

1.4

density

rel

1.1

1.2

1.3

1.4

density

rel

1.1

1.2

1.3

1.4

density

rel

10 20 30 40 50 60 70

diameter (microns)

The difference between particles carried over at t = 20°C and t = 45°C.The yellow grid represents particles carried over at t = 20°C

x

r

0 0.1 0.2 0.3 0.40

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

(a)

x

r

0 0.1 0.2 0.3 0.40

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

p1.52431E+071.42361E+071.32292E+071.22222E+071.12153E+071.02083E+079.20135E+068.1944E+067.18745E+066.1805E+065.17355E+064.1666E+063.15965E+062.1527E+061.14575E+06

(b)

x

r

0 0.1 0.2 0.3 0.40

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04sw

2.845312.655632.465942.276252.086561.896881.707191.51751.327811.138130.9484380.758750.5690630.3793750.189688

(c)

(a) Velocity vectors, (b) pressure contours, and (c) swirl velocity contours in a hydrocyclone

length (mm)

carriedover(%)

1

1

2

2

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A lengthB length

Fiber A

*

*

Fiber B

Influence of the particle length on fractionation

densityrel

carriedover(%)

1

1

1.1

1.1

1.2

1.2

1.3

1.3

1.4

1.4

0 0

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A densityrelB densityrel

*

*

Fiber B

Fiber A

Influence of the particle density on fractionation

Separation on diameter and length as function of the particle density

Influence of the particle diameter on fractionation

Other Institutions

Government Industry

TECHNOLOGY TECHNOLOGY TRANSFER

License agreement

Serviceagreements

Consultingagreements

Customagreements

Licenseagreements

PSL

BENEFITS

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

Feed 36 50 59.1 67.1 73.1

Feed Flowrate (kg/min.)

AcceptsRejects

Fibre Coarseness (mm)

Coarseness vs. flow rate for synthetic fibres for Bauer cleaner