Simulation Techniques and Scientific Computing

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http://www.mb.uni-siegen.de/sts

Simulating an Electrodialysis Desalination Process using HPCK. Masilamani1, J. Zudrop1, M. Johannink2, H. Klimach1 and S. Roller1

1Simulation Techniques and Scientific Computing, University of Siegen 2Aachener Verfahrenstechnik, RWTH Aachen University

Flow channel with spacer

Fluid flow

Diffusion and interaction of ions and water molecules

Membrane

Diffusion of ions

Flow channel with spacer and Membrane

Electrodynamics

Surface

Volume Volum

eCoupling

nk

jk

J e,e

E

Je,

e

E, B

r · ~v = 0

⇢

✓@~v

@t+ ~v ·r~v

◆= −rp+ µr2~v + ~F|{z}

⇢~g+⇢e(~E+~v⇥ ~B)

Incompressible Navier-Stokes equation

@nk

@t+r · (nk~v) = −r ·~jk

Maxwell-Stefan equation

rχk − ~Fk =

NsX

l=1

⇣χk

~jl − χl~jk

⌘

ntDk,l

Nernst-Planck equation@nk

@t+r · (nk~v) = r ·

⇣ntDk,l

⇣rχk − ~Fk

⌘⌘

Maxwell equationsr · ~E =

⇢e✏r✏0

r · ~B = 0

r⇥ ~E = −@ ~B

@t

r⇥ ~B = µrµ0

~Je + ✏r✏0

@ ~E

@t

!

0.3%FRESH WATER LAKES & RIVERS

Breakdown of Fresh Water

30%GROUND WATER

70%ICE & SNOW COVER IN MOUNTAINOUS REGIONS

2.5%FRESH WATER

Total World Water

97.5%SALT WATER

20 21 22 23 24 25 26 27 28 29 210 211 212

Number of nodes

0

50

100

150

200

Par

alle

lEffi

cien

cy(%

)

262144 elements

20 21 22 23 24 25 26 27 28 29 210 211 212

Number of nodes

0

20

40

60

80

100

Par

alle

lEffi

cien

cy(%

)

65536 elements/node

20 21 22 23 24 25 26 27 28 29 210 211 212

Number of nodes

0

20

40

60

80

100

Par

alle

lEffi

cien

cy(%

)

SF-LBM, 66.2× 106 elementsMS-LBM, 66.2× 106 elements

20 21 22 23 24 25 26 27 28 29 210 211 212

Number of nodes

0

20

40

60

80

100

Par

alle

lEffi

cien

cy(%

)

SF-BM, ≈63 thousand elements/nodeMS-LBM, ≈63 thousand elements/node

SeederGeometryGeneration

AotusLibrary

AotusConfiguration

APESAdaptable Poly-Engineering Simulator

HarvesterPost-ProcessingAnalysis

AtelesDiscontinuous Galerkin(DG)

MuriquiSpace-Time DG

MusubiLattice Boltzmann

TreElMLibrary

Library access

File access

ConfigurationLua Scripts

GeometrySTL Files

ResultsVTK Files

- +

I

e- U

Cathode

R

Anode

● ● ● ● ● ● A-

C+ +++

+

+

AEM

-

-

- - -

-

-

CEM

+++

+

+

AEM

A-

C+

A-

C+

-

-

- - -

-

-

CEM

diluate concentrate diluate

Inlet: Sea water

Outlet: Potable water

PressureSensor

Distribution Channel

VolumeFlow RateSensor

Electrodialysis Stack

Spacer

0 0.05 0.1 0.15 0.2 0.250

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5x 104

Velocity, uch [m/s]

Pres

sure

dro

p, ∇

pch

[pa]

Musubi single fluid simulationSingle−spacer experiments via ζ model5 Flow channels7 Flow channels3 Flow channels

Spacer act as mechanical stabilizer

rptot =

✓���*0⇣dis + ⇣sp

◆⇢u2

2

⇣sp = ✓1Re✓2

✓lspdh

◆✓3

+ ✓4

•Octree based•Highly scalable•End-to-end parallel•Allows coupling of solvers

Musubi•Flow channel with spacer geometry

Ateles•Membrane and electrodynamics

•In the 21st Century, supply of mankind with sufficient clean drinking water is a major challange.

•The availability of fresh water is limited.

Species transport in the spacer filled flow channel

Electromagnetic wave propagation with curved obstacles

Motivation Goal Multi-physical Heterogeneous System

Simulation Results APES framework

ScalabilityElectrodialysis Process

Musubi (LBM solver)• Laboratory woven spacer on

Hermit Cray XE6 system

• Single fluid and multi-species LBM up to 1024 nodes (32,768 processes)

• Single fluid LBM = 169 FLOP, Multi species LBM = 783 FLOP for 3 species

Strong Scaling Weak Scaling

Ateles (Maxwell solver) • Periodic domain on SuperMUC

• 5th order spatial scheme with Maxwell equations on up to 2048 nodes (32,786 processes)

• 232 x #(degree of freedom) FLOP for 4th order Runge-Kut-ta time integration

Experimental setup Validation of simulation results

•To understand and optimize the elec-trodialysis process using high perfor-mance computing (HPC).

Simulation Techniques and Scientific ComputingProf. Dr. Ing. Sabine Roller