Integrated Modeling of MHD
Flows, Corrosion/Deposition
and Tritium Transport in
Liquid-Metal Blankets
Sergey Smolentsev (UCLA) and the US MHD/Thermofluid Team
International Workshop on LM Breeder Blankets
Sept. 23-24, 2010
CIEMAT, Madrid (Spain)
OBJECTIVES
• Update on development of integrated modeling tools for MHD flows, Heat & Mass transfer (corrosion, deposition, T transport)
• Show modeling examples (MHD mixed convection, MHD corrosion, T permeation)
• Update on construction of a new PbLi loop at UCLA
• Suggest for cooperation in particular areas
Examples of ongoing collaboration
• R. Moreau (Laboratoire SIMAP, France): MHD flows in a fringing field, MHD turbulence, MHD buoyant flows, LM corrosion
• L. Bühler, C. Mistrangelo (Forschungszentrum Karlsruhe, Germany): MHD code validation/comparison, identification of key MHD phenomena for LM blankets
• S. Cuevas (Centro de Invest. in Energia, Mexico): vortical MHD flows, computational MHD
• A. Shishko (Institute of physics, Latvia): LM corrosion
• Z. Xu (SWIP, China): MHD flow in a duct with FCI
• J-US TITAN 1-3: MHD flows for LM blanket applications
MHD/Thermofluid considerations for S-C, DCLL, HCLL
MHD related issue / phenomena S-C DCLL HCLL
1. MHD pressure drop *** ** **
2. Electrical insulation *** ** *
3. Flow in a fringing magnetic field *** *** **
4. Buoyant flows ** *** ***
5. MHD instabilities and turbulence *** *** *
6. Complex geometry flow and flow balancing *** *** ***
7. Electromagnetic coupling *** ** ***
8. Thermal insulation * *** *
9. Interfacial phenomena *** *** *
*- not applicable or low importance; ** - important; *** - very important
S-C – self-cooled, DCLL – dual-coolant lead-lithium, HCLL – helium-cooled lead-lithium
S. SMOLENTSEV, R. MOREAU L. BÜHLER, C. MISTRANGELO, “MHD Thermofluid
Issues of Liquid Metal Blankets: Phenomena and Advances,” ISFNT 9, 2009.
MHD effects are, traditionally, the major considerations
for LM flows. But there are more…
Ancillary system - “Cold” leg
Deposition
T leakage into environment
T extraction
Cleaning up
Blanket - “Hot” leg
Corrosion
T production and transport
T permeation
Formation of He bubbles
Trapping T by He bubbles
Coupling between various physical processes in the blanket and within the
ancillary system requires I N T E G R A T E D M O D E L I N G !
MH
D flo
wH
D tu
rbu
len
t flow
Development of integrated modeling tools
• • Continuing to develop HIMAG as a basic MHD/Heat Transfer solver –code acceleration is the major objective. Recent implementation of “wall functions” allows for code acceleration by factor 5-20 !
• CATRIS is a new mass transfer solver coupled with HIMAG – just started. Various models from “dilution approximation” to “multi-fluid models”
• New PHENOMENOLOGICAL MODELS for tritium transport, interfacial phenomena and corrosion/ deposition need to be developed – in progress
CATRIS: MATHEMATICAL MODELS
1. Dilution approximation, Ci<Ci0
2. Lagrangian particle tracking, Ci>Ci0
3. Multi-fluid model, Ci>>Ci0
1
Kp
p k
k
dV
dt
V
F
( ) ( )ii i i i
CC D C q
t
V
1
Ni
i i ij
j
Jt
V
1
Nk k k ki i
i i i i i ij
j
Vt
VV σ g P
Mixed Convection – MHD equations and energy
equation are solved simultaneously
• Strong Archimedes forces in PbLi,
cause buoyant flows
• Forced flow ~ 10 cm/s
Buoyant flow ~ 30 cm/s
• Affects the temperature field in the solid,
interfacial temperature, heat losses and
tritium transport – all IMPORTANT!
Rapidly decaying volumetric heating
results in pronounced radial temperature
gradients in the PbLi
Our goal is to model buoyant flows in a DCLL blanket for ITER and DEMO
0
5
10
15
20
0 5 10 15 20 25 30 35 40
FSLiPbSiC
Po
wer
Den
sity
(W
/cm
3)
Radial Distance from FW (cm)
Radial Distribution of Power Density in DCLL TBM Components
Neutron Wall Loading 0.78 MW/m2
LL
SiC FS
PbLi
Ferritic steel
Mixed convection: 3D modeling
Reduction of 3D effects and tendency to quasi-two-dimensional state
as Ha number is increased have been observed
Ha=100 Ha=400 Ha=700 Ha=1000
g g g
Re=10,000
Gr=107
a/b=1
Mixed convection: downward flow
Ha = 400; Re = 10,000, Gr = 1e+07 Ha = 1000; Re = 10,000, Gr = 1e+08
Hot spot !
g
Mixed convection: 1D versus 3D
Ha=400 Ha=700 Ha=1000
Fu
lly d
evelo
ped
1D analytical solution
-Flow is Q2D
-Flow is fully developed
Major assumptions of the 1D theory
have been verified with 3D modeling.
1D vs. 3D comparison is fair
Full solution Wall functions BC Wall functions BC
MODELING corrosion experiment in Riga
2 2
0
2 2
0
10
BU U B dP
z y z dx
2 2
0 02 20
B B UB
z y z
2 2 2
2 2 2( )
C C C CU D
x x y z
1 1: 0, 0
1 1: 0, 0
w w
w w
B Bz b U
z t
B By a U
y t
0 0
0 0
0 : 0
: ( ) 0
: ( ) 0
x C
Cz b D K C C or C C
z
Cy a D K C C or C C
y
Two BC types have been tested(C0 is the saturation concentration at given t)
• PbLi loop
• EUROFER
• B=0, B=1.7 T
• T=550C
• U=2.5; 5 cm/s
• Time=2000 hours
• Duct: 2.7x1 cm2
• Two 12-cm sections of
10 samples in a row, one section at
B=0 and one at B=1.7 T
Bucenieks I., Krishbergs R., Platacis E., Lipsbergs G., Shishko A.,
Zik A. and Muktepavela F., Investigation of corrosion phenomena in
Eurofer steel in Pb-17Li stationary flow exposed to a magnetic field,
Magnetohydrodynamics, 42, N° 2-3, pp. 237-251, 2006
Riga experiment : modeling vs. experiment
0:BC C C
Riga group: C0=6.26 g/m3, K=4.27E-05 m/s
0: ( ) 0C
BC D K C Cn
Grjaznov et al: C0=3.25 g/m3
MASS LOSS: comparison with the experiment
430
215
Mass loss,
m/y
ear
Tritium transport in poloidal flows
• DCLL DEMO blanket conditions (outboard)
• Poloidal flow in a front duct with a 5-mm SiC/SiC FCI
• HIMAG is used to simulate MHD flow, assuming fully developed flow conditions
• CATRIS is used to simulate tritium transport in the multi-material domain, including PbLi flow, SiC FCI and Fe wall
• Goals: (1) T permeation into He; (2) sensitivity study
z
x
yB
Inflow
Outflow
FCI
2.0
m
2.2
6 m
0.3 m
DCLL Geometry (not to scale)
207 mm
RAFS wall 5 mm
thick
SiC wall 5 mm thick
231 mm
z
y
2 mm
gap
211 mm
•Neutron wall loading (peak): 3.08 MW/m2
•Surface heating: 0.55 MW/m2
•PbLi Tin/Tout: 500/700C
•Flow velocity: 6.5 cm/s
•Magnetic field: 4 T
•Inlet T concentration: 0
•T generation profile: 4.9E-09 Exp(-3y), kg/m3-s
Tritium transport: results
# D S σ T leak
10-9 m2s-1 mol m-3Pa-1/2 Ω-1m-1 %
1 1 0.01 5 1.30
2 2.54 0.01 5 1.40
3 7 0.01 5 1.35
4 2.54 0.0005 5 2.08
5 2.54 0.001 5 1.99
6 2.54 0.005 5 1.65
7 2.54 0.05 5 0.60
8 2.54 0.1 5 0.35
9 2.54 0.01 50 0.36
10 2.54 0.01 500 0.06
Total tritium loss in the front duct
(sensitivity study)
Total T leakage < 2%
• Due to very low diffusion coefficient of T in SiC, FCI can be considered as a T permeation barrier
• Tritium permeation occurs mostly from the gaps, especially from the Hartmann gap
• Electrical conductivity of the FCI has indirect effect on T transport via changes in the velocity profile
• Total T leakage into He can be estimated as 2% of all tritium generated in the same duct
Experiments with simulants (Hg)
UCLA MHD facilities Magnetic field up to 1.7 T
Manifold experiment: to
address flow distribution in
a complex 3D geometry,
where the LM flow from the
inlet splits into 3 poloidal
channels – tendency to
more uniform flow in a
strong magnetic field
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=421
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=547
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=687
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=827
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=960
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1097
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1218
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1358
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1503
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1639
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1770
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1894
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2032
Re
r, R
ec,
Re
l
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2170
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2290
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2429
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=421
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=547
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=687
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=827
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=960
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1097
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1218
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1358
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1503
Re
r, R
ec,
Re
l
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1639
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1770
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=1894
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2032
Re
r, R
ec,
Re
l
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2170
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2290
Re
0 5 10 15
x 104
0
2
4
6x 10
4 Ha=2429
Re
Prequalification
experiment: to test new
MHD flow diagnostics
and to address 3D->2D
transitions in duct flows
in a strong magnetic
field
Mixed convection
experiment:
the magnet will be turned
vertically to study buoyant
MHD flows in poloidal-like
channels
New MHD PbLi loop is under construction
at UCLA – completion in 2011
Max. magnetic field ~ 1.7 T
Space inside the magnet ~ 1 x 0.2 x 0.2 m
Temperature ~350-400C
Max. pumping capacity ~ 0.5 L/s, 0.15 MPa
Upgrade in 2011/2012 to increase
pumping capacity (1 L/s, 0.3 MPa),
and operating temperature (500C)
MHD / Heat Transfer
Corrosion/Deposition
Material testing
CONCLUDING REMARKS
• Development of computational tools to model integrated MHD, Heat & Mass Transfer processes in LM blankets and ancillary systems is in progress
• New MHD PbLi facility is constructed at UCLA with completion in 2011 and major upgrades in 2012
• We look for cooperation:
- Phenomenological models (corrosion, deposition,
T transport, He bubble formation, T trapping in He)
- MHD/Heat&Mass transfer code development and
validation
- Experiments in PbLi (MHD, Heat & Mass Transfer,
material testing)