UBC

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PULP AND PAPER COMPUTATIONAL FLUID DYNAMICS
APPLICATIONS
UBC Mechanical Engineering CFD Modeling Group
HYDROCYCLONES

• Objectives
• Improve predictions of swirling flows
• Develop mathematical models to predict the
  classification of fibers
• Model
• Discretization using block structured curvilinear
  grids
• Modified k-? model for highly curved turbulent
  flows
• Particle tracking through explicit time marching
  based on force balance
• End-Users
• Pulp mills requiring high efficiencies for fiber
  cleaning and fractionation

DIGESTERS

• Objectives
• Model the delignification process occurring
  within digesters
• Calculation of liquid and solid conservation
  equations for multi-dimensional flow
• Model
• Liquid-solid two-phase flow model coupled to the
  energy and conservation of species equations
• Benefits
• Better understanding of process to improve yield
  and fiber strength

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 Jason Zhang Kegang
Zhang
Dr. Martha Salcudean Weyerhaeuser Industrial
Research Chair Fellow C.S.M.E., F.C.A.A., F.R.S.C.
Dr. Ian Gartshore Fellow C.A.S.I
RECOVERY BOILERS

• Objectives
• Develop modeling tools to improve existing
  designs and operating procedures, and to lower
  carry-over and environmental load
• Analyze performance of different air systems and
  liquor firing strategies
• Model
• 3-D orthogonal computational method with k-?
  turbulent model, liquor combustion, particle
  tracking, and wall and gas radiation
• Flow equations coupled to the energy and species
  conservation equations
• Predicts gas flows, composition, temperature, and
  liquor-smelt-char particulate distribution
• Benefits
• Powerful modeling tool to optimize recovery
  boilers, reduce plugging rates, reduce time
  between water washes, analyze performance of
  different air systems, improve operating
  procedures, lower carry-over, and reduce
  environmental load

FUNDING - NSERC - FRBC - B.C. Science Council -
Weyerhaeuser - CANFOR - PSL
WOOD KILNS

• Objectives
• Determine the air flow and moisture distribution
  in wood kilns
• Optimize kiln operations and improve wood quality
• Model
• 3-D curvilinear non-orthogonal computational
  method with transient mass and heat transfer
  calculations to model the drying process
• End-Users
• Kiln operators and manufactures

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Flexible Fiber Rotation
BARK BOILERS
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• Objectives
• Develop a comprehensive bark boiler gas flow and
  combustion model
• Optimize the thermal efficiency and emissions of
  boilers and identify promising and cost-effective
  design upgrades
• Model
• Momentum and conservation equations for mass,
  energy and gas species concentration using the
  turbulence k-? model are solved simultaneously
• Chip combustion includes the evaporation of
  water, release of volatile gases and gas
  radiation heat transfer
• End-Users
• Bark boiler operators and manufacturers

Tube Position
FLUID-FIBER INTERACTION
HEADBOXES

• Objectives
• Investigate experimentally flows in headboxes
  with a range of fiber concentration
• Develop computational-based methods to simulate
  the complex flows occurring in headboxes
• Model
• 3-D curvilinear non-orthogonal computational
  method with low Reynolds k- ? model and with
  non-isotropic, non-linear versions of the k-?
  model
• End-Users
• Headbox manufactures and paper mills

• Objectives
• Predict and control fiber fractionation according
  to wood species
• Develop a model of flexible fiber motion that
  includes wall interaction
• Compute trajectories of fibers in complex flows
• Model fractionation during screening and in
  hydrocyclones
• Benefits
• Improve supply of uniform fibers and increase
  quality and consistency of pulp