Fluent & Multiphase Flows

Salmane Saadani

Fluent Sweden AB

Historical Background The original FLUENT software was developed at the

University of Sheffield, UK in the 1970s (Tempest)

1983 title in FLUENT was transferred to a New HampshireCompany called ‘Creare’

1988 Fluent group at Creare becomes Fluent Inc.

1999 Fluent Sweden opened

2006 Fluent has become part of the Ansys Group.

Fluent Inc. HQ - Lebanon, NHEvanston, ILSanta Clara, CAAn Arbor, MIMorgantown, WV

N. America Europe Asia/PacificFluent UKFluent FranceFluent GermanyFluent ItalyFluent SwedenFluent Benelux

Fluent Asia-Pacific, JapanTokyo and OsakaFluent India

Worldwide Offices

Numerous offices worldwide in additionto various distributors

FLUENT SWEDEN

Services Software Sales

Technical support

Training

Consulting

14 Employees 5 Ph.D

5 Siv Ing

Fluent & Multiphase FlowsFluent Offers:

A wide range of proven and leading edgeMultiphase models.

Advanced meshing tools.

Optimal Parrallelization schemes

Worldwide experience and involvement inMultiphase Applications

Fluent & Multiphase Flows

It Means:

Accurate flow simulations

Accurate geometry representation

Quick solutions

Ability to solve unconventional problems

Multiphase Flow Regimes Bubbly flow/ Droplet flow/

Particle-laden flow = Discretesecondary phase structures(bubbles, droplets, solidparticles) in a continuousprimary phase

Slug flow = Large bubbles in acontinuous liquid

Annular flow = Continuousliquid along walls, gas in core

Stratified / Free-surface flow= Immiscible fluids separatedby a clearly-defined interface

Jet flow = thin liquid coresurrounded by bulk gas phase

Film flow = thin liquid layerflowing along wall boundaries

Bubbly flow / Droplet flow /Particle-laden flow

Slug flow

Annular flow

Jet flow Film flow

Free-surface flow

Fluent Multiphase Models

Volume of Fluid (VOF) Model (free-surface / stratifiedflows, filling, sloshing)

Mixture Model (bubbly, droplet, Granular Flow)

Discrete Phase Model (bubbly, droplet, particle-laden flowswith α ≤ 10%)

The Eulerian model (Advanced Particle Modeling)

• Kinetic theory of granular flows

• Population Balance Model

Population Balance Model Nucleation

Chemical Reaction

Phase change

• Boiling

Growth

Chemical Reaction

Crystal growth

Breakage

Particle-particle collisions

Turbulence and shear

Aggregation

Particle-particle collisions

Coagulation

Coalescence

Agglomeration

Time

Time

Nucleation: Creation of particles

Growth (Shrinkage)

Aggregation

Break-up

Meshing

•Tetraheadral

•Hexaheadral

•Multiple Mesh Type Combinations

•Hexcore Mesh

•Moving Deforming Mesh

•Polyheadral

Meshing

Hybrid Mesh

439,781 cellsPolyhedral Mesh

174,552 cells

Grid reduction by a factorof 3 to 5

Mixing Tank

1119006 cellsFine Tetrahedral Mesh

370549 cellsCoarse Tetrahedral Mesh

237404 cellsPolyhedral Mesh

Velocity Profiles Turbulent Kinetic Energy Profiles

Coarse Tetrahedral: 370,549 cellsFine Tetrahedral: 1,119,006 cellsPolyhedral: 237,404 cells

Geometry

0

0.2

0.4

0.6

0.8

1

1.2

0 0.1 0.2 0.3 0.4 0.5z/H

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0 0.1 0.2 0.3 0.4 0.5z/H

Mixing Tank

13001850Polyhedral with PBCS

2700~41800Fine Tetrahedral with PBCS

Memory(MB)

Relative SingleCPU TimeIterations

Mixing Tank

ParallelParallel I/O Market leader in Parallel Performance Fast case and data file read/write Very Good ScalabilityOther Parallel Enhancements Load Balancing (Prevents Bottlenecking) Ability to read Hexcore meshes directly into

parallel without partitioning

FLUENT 6.3

Parallel Data File Write

9.834

5.282Xeon/GigE

5.612Opteron/Infiniband6.334

6.68

Speed-up

FLUENT 6.3/FLUENT 6.2

Numberof CPUs

Platform andInterconnect

Fluent Involvement

Fluent works closelywith industry leadersworldwide to push thelimit of CFD further

Conclusion FLUENT continues to

push the boundaries for More accurate flow simulations

More accurate geometrymodeling

Quicker solutions