Analiza zjawisk termo-hydraulicznych w kablu nadprzewodnikowym typu CICC z centralnym kanałem chłodzącym dr inż. Monika Lewandowska.

Analiza zjawisk termo-hydraulicznychw kablu nadprzewodnikowym typu CICC

z centralnym kanałem chłodzącym

dr inż. Monika Lewandowska

Plan seminarium

• Wprowadzenie– Cable in Conduit Conductors (CICC’s)– CICC’s w tokamaku ITER– Istota zjawiska termosyfonu

• Charakterystyka badanej próbki• Opis eksperymentu• Wyniki• Perspektywy

Cable in Conduit Conductors (CICC’s)

HoleBundle

Scheme of the early CScheme of the early CIICC proposalCC proposal

Modern realizations of CICCs to be applied in magnets for fusion

technology

Przekrój typowej żyły kabla nadprzewodnikowego typu CICC

The ITER project

• InternationalThermonuclearExperimentalReactor

• Aim: produce energy from nuclear fusion

• High magnetic field (11 T) to confine the hot plasma

• Heavy heat loads on the coils due to neutron flux

CICC’s mandatory!

Central Solenoid: 1152 Nb3Sn Strands, 13 T, 45 kA Toroidal Field Coil: 900 Nb3Sn

+ 522 Cu Strands, 68 kA, 11.3 T

Poloidal Field Coil: 1440 NbTi Strands, < 45 kA, < 6 T

CICC’s in ITER

Gravity-buoyancy effect in a dual channel CICC

In a vertically oriented dual channel CICCwith the coolant flowing downward, power deposition in the bundle region causes the reduction of the flow velocity due to the reduced density of helium. Eventually, the back-flow can occur, leading to quench.

Charakterystyka badanego kabla (ITER TF)

Supercond. strands Sub cable Sub-cable wrap Central spiral Final cabling stage Bundle void fractionCable jacket

ø 0.82 mm, 2 μm Cr plating, Cu/nonCu = 1(2 sc + 1 Cu)×3×5×5 strands + 3×4 Cu coreSingle layer 70 μm steel foil, ~50% coverageInner/outer ø 7/9 mm, 30% open surface6 wrapped sub cables, 443.3 mm twist pitch0.332Inner/outer ø 40.5/43.7 mm, 316 LN steel

Schemat oprzyrządowania

próbki

Fotografie oprzyrządowania próbki

Experimental setup

SULTAN = SUpraLeitende TestANlage = Test facility for superconductors

Supercritical He:

Tinlet = 4.5 K or 6.5 K

pinlet = 1 MPa

= 10 g/smaxm

Typical set of raw data

0 200 400 600 800 1000 1200 14006,2

6,4

6,6

6,8

7,0

7,2

7,4

7,6

7,8

5

6

7

0,0

0,5

1,0

1,5

2,0

2,5

Te

mp

era

ture

[K

]

time [s]

T in T0 TL1 TR1 TL2 TL3 TL4 TR4 TL5 TL6 TR6 TL7 TR7 T8 T out

mas

s flo

w r

ate

[g/s

]

Hea

ter

curr

ent

[A]

Results

R.Herzog, M.Lewandowska, M.Calvi, M.Bagnasco. C.Marinucci, P.Bruzzone, Helium flow and temperature distribution in a heated dual channel CICC sample for ITER, accepted for publication in IEEE Transactions of Applied Superconductivity

• We measured and analysed the temperature deviations from the 1D model, which assumes homogenous temperature in every cross section n

• After a heated region the deviations ΔT disappear exponentially with distance.

• The magnitude of ΔT is proportional to the heating power per unit length and inversely to the mass flow rate.• ΔTmax may be readily estimated from the obtained results.

Assessment of the helium velocity in the cooling channel and in the bundle

vH was estimated from the time delay between the rising edges of spot heater SHa current and TRa readings.

Friction factor correlations

Hole• ITER DDD

• Zanino

Bundle• ITER DDD

• Katheder

• Porous medium D-F

• Porous medium A

034.0Re45.0 HHEuf

75.32

ln5.22

)(

HhUSH D

h

fhR

299.0

039.088.11)(

h

ghhR

2/Re HUSHHh

fD

hh

R. Zanino, et al., IEEE Trans. Appl. Supercon. 10 (2000) 1066-1069

h – spiral height, w – width, g – gap

051.0

Re

5.19188.072.0

B

BEuf

0231.0

Re

5.1917953.0742.0

B

BEuf

baf BBUS Re/

14.0Re/Re/ BBBUS baf

H. Katheder, Cryogenics 34 (1994) 595–598 [ICEC supplement]M. Bagnasco, et al, CHATS AS 2008

Pressure drop and helium

velocity in TFS experimental

data and simulation

0 4 8 1 2to ta l m a ss f lo w ra te (g /s)

0

2 0 0

4 0 0

6 0 0

pres

sure

gra

dien

t at 4

.4 K

(Pa

/m) H o le fric tio n fa c to r: Z a n in o

T F S -0 7 W 1 d a taK a th e d e rP o ro u s m e d iu m D -FIT E R D D DP o ro u s m e d iu m A

0 4 8 1 2to ta l m a ss f lo w ra te (g /s)

0

2 0 0

4 0 0

6 0 0

pres

sure

gra

dien

t at 4

.4 K

(Pa

/m) H o le fric tio n fa c to r: IT E R D D D

T F S -0 7 W 1 d a taK a th e d e rP o ro u s m e d iu m D -FIT E R D D DP o ro u s m e d iu m A

Pressure drop and flow velocitiesexperimental data and final model

0 4 8 1 2m a ss f lo w ra te (g /s)

0

1 0 0

2 0 0

3 0 0

4 0 0

5 0 0

pres

sure

gra

dien

t at 4

.4 K

(Pa

/m) T F S -0 7 W 1 d a ta

H o le : 0 .7 5 * IT E R D D DB u n d le : 0 .7 3 * K a th e d e r

0 4 8 1 2m a ss f lo w ra te (g /s)

0

2 0

4 0

6 0

8 0

velo

city

(cm

/s)

H o le : 0 .7 5 * IT E R D D DB u n d le : 0 .7 3 * K a th e d e r

v H (M L )

v H (M C )

v B (M L )

v H m o d e l

v B m o d e l

)(

totaltotal

B mfmm

Heat transfer in the ITER TF conductor

Stationary two-channel model

QTTphx

TCm

TTphx

TCm

BHBHB

pB

HBBHH

pH

temperature in the cooling hole

temperature in the cable bundle

mH

mB

phBH

TB

TH

B.Renard, et al , Evaluation of thermal gradients and thermosiphon in dual channel cable-in-conduit conductors, Cryogenics 46 (2006) 629-642

Lx

LxLPxQ

0

0/)(

)/(

,

ptotalinref

refrefpp

CmPTT

pTCC

Constant thermophysical parameters

Analytical solution

BHBHHH

BHBB hhxTT

hxTT

),(

),(

Average heat transfer coefficient between bundle and hole

0 4 8 1 2T o ta l m a ss f lo w ra te (g /s)

0

2 0 0

4 0 0

6 0 0

8 0 0

1 0 0 0

h BH

(W

/(m

2 K))

T F S

C. Marinucci, et al, Analysis of the transverse heat transfer coefficients in a dual channel ITER-type cable-in-conduit conductor, Cryogenics 47 (2007) 563-576

Temperature profiles along the sampleexperimental data and simulation

0 1 2 3 4x (m )

0

0 .5

1

1 .5

2

2 .5

T (

K)

H ea ters H 1+ H 2 P = 4 WP = 1 0 WP = 2 0 WP = 3 0 WP = 4 1 WP = 5 1 W

0 1 2 3 4x (m )

0

0 .5

1

1 .5

2

2 .5

T (

K)

H ea ter H 2P = 2 WP = 6 WP = 1 0 WP = 2 0 WP = 3 0 WP = 4 0 WP = 5 0 W

K) W/(m535

g/s 82

BH

total

h

m

Thank you for your attention