Christophe Duwig 1, Henrik Hassing 2, Elisabeth Akoh Hove 2

1 R&D division - Haldor Topsøe A/S & 2 Force Technology

Using OpenFOAM to model of complex industrial devices

Outline of the talk� Shortly about Haldor Topsøe A/S

– What does CFD do for us

� Replacing commercial CFD with OpenFOAM

– OSFRI initiative in Denmark

� How does OpenFOAM fit in the context?

– LES with detailed chemistry: example of hydrogen auto-ignition

– LES of a swirling flow

Haldor Topsøe A/S – www.topsoe.com� Founded by Dr. Haldor Topsøe in 1940

– selling high quality catalyst since 1944

– selling high quality processes since 1957

� Business areas:– Syngas

� Hydrogen & gasification-based tech.

� Ammonia

� Methanol/ DME

– Refinery

– Environmental / gas cleaning

� deNox applications

� sulfuric acid (WSA)

� CatOx

� Automotive

In real life, it may look like …

CFD applications in HTAS

� Reforming (hydrogen, ammonia, …)– furnaces simulations

– Reformer simulation (air and oxygen rich flames)

– Turbulent heat transfer

� Environmental– Ammonia/ Urea mixing in SCR devices

– Heat transfer in sulfuric acid condensers

– Particle depositions in SCR catalysts

� Refinery– Multiphase flows

– Heat & Mass transfer

Traditional fields of applications for commercial codes

OSFRI initiative in Denmarkhttp://www.osfri.dk

When did it start?�A DANSIS meeting in October 2007 on new trends in CFD and with a special focus on OpenFOAM revealed a strong interest – 110 participants!

What do we do?�Open Source CFD has a clear potential but also barriers and dangers…

�However the benefits and dangers are almost the same for all new users!

�So – why not create national competences, share knowledge, test cases, user guides and not do the same mistakes?

High energy of activation

Need of the same catalyst

Need a critical mass

Create the OSFRI consortium!

The need of funding

An application for public funding was tailored by H. Hassingat FORCE Technology.

� A a total budget of 7.4 mill. DKK including 3.4 mill. DKK in public funding (1.00 €=7.43895 DKK)

� The results should be made available to all interested Danish companies (and others!)

�FORCE Technology

�Grundfos Management

�Niro A/S

�MAN Diesel A/S

�Ødegaard & Danneskiold-Samsøe A/S

�Babcock & Wilcox Vølund A/S

�Haldor Topsøe A/S

�FLSmidth Airtech A/S

�FLSmidth A/S

�Aalborg University

�Technical University ofDenmark

What is the outcome?Between the primary participants, the expected outcome are more or less like:

� Organize training sessions

� Use Open Source for ‘standard’ cases

– Particles modeling

– Combustion modeling

– Swirling flow modeling

� Open Source will be used for 50-70% of the volume which will be increased drastically

However OpenFOAM also opens new avenues

Detailed modeling of state-of-the-art devices

� Application to flames

– about the physics

– an example

– what is new with OpenFOAM

� Application to Large Eddy Simulation

– about the physics

– an example

– what is new with OpenFOAM

Example of turbulent flame

� Even simple a Bunsen flame is complex as shown beside!

� There is a need of advanced investigation techniques (experimental and numerical), here laser based OH-PLIF

� Does it happen only in the lab. ??? … NO!

� But traditional CFD over-simplifies the story -> need to do better!!

OH PLIF from Buschmann et al., 26th Symp.

On Combustion, pp. 437-445, 1996

How does a flame front really look like? what we see and what we hear

How do we address these problems?

� Large Eddy Simulation

– Fine mesh

– Low dissipation numerical schemes

– Small time steps

– Large computers

� Advanced models for combustion

– Accurate thermo-chemistry description – realistic kinetics

� Reads ChemKin format!

– Turbulence/chemistry: ILES/EDC/ PaSR

� OpenFOAM is suitable because

– Open source = flexibility

– Fair choice of numerical schemes that can be used for LES/ I-LES

– Runs in // without additional costs!

Cabra’s lifted flame

T~305 KH

2 /N2

T~1045 K

H2 O

/O2 /N

2

T~1045 K

H2 O

/O2 /N

2

X

XIG

OBS: not on scale!

Cold high-speed H2 jet in Hot oxidant with 17% O2

Lift-off hight

Flame location

Large Eddy Simulation using OpenFOAM

Customized solver based on the OpenFOAM library solving filtered continuity and Navier-Stokes

low-Mach number & ideal gas assumptionpressure coupling is PISOSmagorinski SGS closuresecond order discretizationsolver CG with AMG-preconditioning for pressureNumerical grid of cell size in the jet region h~d/24 (~0.6 millions Hex)Costs: ~24h for one jet-flow-through on 8 procs.

Filtered specie- and enthalpy-equations:( ) ( )( ) ( ) hDhu

t

h

)Y(YSc

DYut

Y

h

jTiiii

∇

+⋅∇=⋅⋅∇+

∂∂

+

∇

+⋅∇=⋅⋅∇+

∂∂

∆

∆

∆

∆

~

Pr

~~~

~~~~~

υρρρ

ωυρρρILES :

We resolve the reaction layer in the

LES grid!!

Complex chemistry is

neededExample:

1. H2 oxidation by Juan Li et al., 2004; 9 species & 19 reactions

2. CH4, GRI3.0, 53 species

3. ….

Flame turbulence interaction

Cold H2/N2 jet issuing into a hot coflowTcoflow=1045K – O2=17%

Radical species : OH & HO2 fields

HO2 precedes OH: ignition precursor!!

Cold H2/N2 jet issuing into a hot coflow - Tcoflow=1045K – O2=17%

Example of turbulent swirling flow

Example: incompressible swirling jet

0=⋅∇ u

( ) ( ) ( )upuuuuuut

u ∇⋅∇+∇−=−⋅∇+⋅∇+∂∂ ν

ρ1

Filtered continuity and Navier-Stokes

• Numerical methods (solver oodles)• spatial discretization: cubic limited• temporal discretization: 2nd order implicit

•Numerical grid• typical cell size in the shearlayer h=d/50• number of cells: 1.5 millions (hex)

•Costs: 3-4 days on 32 procs. For 50000 time steps

I-LES

Instantaneous flow field - 1

Streamwise velocity Azimuthal velocity

Instantaneous flow field - 2

Streamwise velocity

Summary & future work� OSFRI initiative is a success

– Open-source CFD need catalysis to enter the industry

– Critical mass is needed

� OpenFOAM is suitable when dealing with complex turbulent flows and flames = industrial problems!

– Open source = flexibility

� Fit the code to the problem and not the other way around

– Massive parallel runs without additional costs!

� Future actions

– Development of new capabilities

� To the OpenFOAM community: thank you for your work

– Phase II for the OSFRI initiative

Thank you for your attention!☺