by

Greg Nurnberg,gn@fluent.com

Technical Support Engineer

Fluent Inc.www.fluent.com

Breaking the Barrier Between System andComponent Modeling: Coupling RELAP5-

3D© & FLUENT

Relevant Applications

Outline◆ FLUENT & RELAP5-3D© Coupling◆ Introduction to Fluent Inc.◆ What is CFD?◆ Case Studies◆ FLUENT

Capabilities◆ Summary

Contours of Pressure

Need for Fluent & RELAP5-3D© Coupling

◆ Enable an entire system tobe modeled using 1dimensional features ofRELAP5-3D©

◆ Model some components ofthe system in detail usingthe 3 dimensional featuresof FLUENT

◆ The performance of thesystem depends on the flowthrough each component,and vice versa

◆ Boundary conditioninformation is transferredback and forth between thetwo codes

◆ Both the system andcomponent behavior ismore accurately predicted

Benefits of Fluent &RELAP5-3D© Coupling

Courtesy of Center for Multiphase Research, RPI

Fluent Coupling◆ A 1-D model of

the powertrainsystem isconstructed

◆ The intakemanifold isrepresented as a“CFD component”

Contours of Exhaust GasRecirculation 18.9 ms intothe cycle

Courtesy of Cummins Inc..

Fluent Coupling◆ The coupled solution

shows the transientflow in the manifolddue to continuouslyupdated boundaryconditions

◆ The systemperformance is moreaccurately predictedas well Contours of Exhaust Gas

Recirculation

Courtesy of Cummins Inc..

Introduction to Fluent Inc.

◆ Fluent Inc. develops and markets fluiddynamics software for the analysis ofengineering processes

◆ Software can be used for studying:�Fluid flow and heat transfer�Complex reactions, materials, processes

◆ Largest CFD vendor in the world

Fluent Worldwide

ATES, Korea SFI and Aavid, Taiwan

Fluent India

CFD - RES , Australia

Fluent UKFluent FranceFluent GermanyFluent ItalyFluent SwedenFluent Benelux

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

N. AmericaEurope Asia/Pacific

Fluent Asia-Pacific, JapanTokyo and OsakaFluent India

Hi-Key, China

Major Markets Served•Aerospace•Turbomachinery•Power Generation/Nuclear•Chemicals/Petrochemical•Automotive•Computers/Semiconductors•Materials/Metallurgy•HVAC

Computational FluidDynamics

◆ Fluid flow, heat and masstransfer, phase change,chemical reaction, mechanicalmovement, and deformation ofrelated solid structures

◆ Navier Stokes Equations

◆ Numerical Solution Techniques� Finite Difference� Finite Elements� Finite Volume

φφρφρφ Sgraddivt

+Γ=+∂

∂ )div()()( u

How CFD Analysis Works

1. User definesthe problem...

2. A mesh isconstructed

3. Model is set up in Fluent

4. Solution iscomputed and viewed in Fluent!

Case Studies

◆ Tube and Shell Heat Exchanger◆ Steam Generator Flows◆ Coolant Control Valve

Heat Exchanger PerformanceImprovement

◆ Problem:� Under-performing 324

tube heat exchanger� 700mm x 2500mm long

vertical with 200mmnozzles on the tube side

� Tube side flow90757kg/hr at 69.5 C

◆ Solution:� Replace the device� German Chemical

company retains CalGavin Engineers toperform analysis

Courtesy of Cal Gavin Ltd.

Axial Velocities Across the Outlet

Look for local hot spots andtemperature uniformity

Maldistributed Improved

Courtesy of Cal Gavin Ltd.

◆ FLUENT is used tosimulate the flow in asteam generator following asevere loss of coolantaccident

◆ Due to blockage in thecoolant loop and seals,cooling is impaired

Severe Accident Steam GeneratorFlows

◆ The simulation is used to determine the extent of thecooling failure – whether it is restricted to the coolantpiping or extends into the steam generator tubing

Courtesy of the US Nuclear Regulatory Commission

◆ Temperature contours onthe symmetry plane (top)show hot coolant on thetop of the pipe

◆ Velocity vectors (bottom)show the directions of thehot and cool liquid flows

◆ The predicted average hotand cold temperatures arewithin 1.5 – 2K of themeasured values

Severe Accident Steam GeneratorFlows

Courtesy of the US Nuclear Regulatory Commission

Severe Accident Steam GeneratorFlows

◆ Predictions of the number oftubes carrying hot flow arecompared to data

◆ FLUENT overpredicts theregion of hot flow by 16tubes, or 7% of the totalbundle

◆ Overall, the CFD results arein very good agreement withdata and provide moreinformation than a limitednumber of thermocouples can

Courtesy of the US Nuclear Regulatory Commission

Coolant Control Valve◆ Dual control valve is used for

automotive HVAC coolantcontrol

◆ Driver and passenger cancontrol temperaturesindependently

◆ Valve motion is simulated usingthe moving mesh feature

◆ Time-varying profiles describethe motion of the valve spools

Courtesy of Robert Bosch Corporation

Coolant Control Valve◆ Deforming mesh

capability has beendemonstrated with thecoolant control valve

◆ When compared tosteady-state analyses,a deforming meshanalysis produces amore realisticrepresentation of flowthrough componentssuch as valves andpumps

Courtesy of Robert Bosch CorporationContours of Velocity Magnitude

Fluent Capabilities◆ Model Building◆ Physical Models◆ Multiphase Models◆ Dynamic Mesh

Adaption◆ Moving and

Deforming Mesh◆ Visualization

Courtesy of BASFContours of Solid Phase

Fluent Capabilities

◆ Model Building� Fully integrated� Solid geometry

modeling

� Geometry and meshimport from CAD/CAE

� Meshing� Mesh visualization and

quality diagnostics

◆ Physical Models� Heat transfer, species transport and reacting flows� Multiple reference frames, sliding mesh and mixing

plane model� Inviscid, laminar

or turbulent

Fluent Capabilities

Courtesy of General Electric

◆ Multiphase Modeling� Particle Tracking� Free Surface Flows� Mixture Model� Fluid-Fluid, Fluid-Solid

Fluent Capabilities

Bubble Column

Fluent Capabilities◆ Dynamic Mesh Adaption

� Improve accuracy• Refine the grid based on flow solution gradients or geometric details

for higher resolution of flow details.� Increase model efficiency

• Add grid resolution only where it is needed

Mesh Coloured by Contours of Static Pressure

Fluent Capabilities◆ Moving and Deforming Mesh

� The moving mesh uses three possible techniques:• moving nodes while preserving connectivity, localized re-

meshing, dynamic layering� The result is a high quality mesh at all times during the

calculation

Velocity Magnitude ContoursMesh Deformation

Fluent Capabilities◆ Parallel Computing

� Parallelization available on networksof workstations or multiple processorworkstations

� Partitioning done automatically

Grid partitions on a utility boilerGrid partitions on a utility boiler

FL5M2 Benchmark on Linux Cluster

0

1000

2000

3000

4000

5000

6000

7000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16Number of Processors

Ben

chm

ark

Thro

ughp

ut

Linear Scaling

Intel Xeon 2GHz 8x2 Cluster,Fast Ethernet InterconnectIntel Xeon 2GHz 8x2 Cluster,Myrinet Interconnect

Fluent Capabilities◆ Visualization

� 3D visualization tools� Animation� Quantitative reports� Integrals and

averages� Customized reports

Plume Dispersion

Summary◆ A number of

industrial applicationshave been identifiedwhich may benefitfrom the coupling ofFLUENT & RELAP5-3D©.

◆ Overall predictions ofthe system andcomponentperformance areexpected to be moreaccurate

Volume fraction of vapor during film boiling