r.valbuena nbi 14-19 march 2002 cngs decay pipe entrance window structural and thermal analysis...

R.Valbuena NBI 14-19 March 2002

CNGS Decay Pipe Entrance Window

Structural and Thermal Analysis

A.Benechet, P.Cupial, R.Valbuena

CERN-EST-ME


Summary1. Structure analysis

• Geometry• Material properties• Boundary conditions• Loading cases• Results

2. Thermal analysis• Assumptions• Material properties• Boundary conditions• Loading cases• Results

3. Thermal and Mechanical Stresses4. Thermal shock5. Conclusions


1. Structure Analysis

1.1 Geometry• external diameter : 1665 mm• internal diameter : 1400 mm• spherical radius : 1891 mm• thickness: 2 mm

1.2 Ti 40 properties• Young Modulus 105 GPa• Yield Strength 280 MPa• Ultimate Tensile Strength Rm 460 MPa

1.3 Boundary Conditions• Fixed in-between flanges

Concrete

Decay Steel Pipe

Titanium window

Steel Flanges


1.4 Loading cases Case 1: 0.3 MPa test pressure Case 2 : 0.1 MPa service pressure

1.5 Results for Case 11.5.1 Analytical :

Allowable stress according to French Pressure Vessel Code (CODAP) :

For Titanium : under resistance test condition:

-under normal service condition :

MPa142e2

PR

f5.1

f

total

membrane

3.2

Rf

tm

3

Rf

tm MPa460R C50T20

m

P

with =>The condition is fullfilled


1.5.1 FEM Analysis

deformations:

Von Mises stress:

=1.8 mm

18.4 36.7 55.1 73.4 91.8 110 128 147 165

The membrane stress is equal to those computed analytically. The red zone is typical of such spherical shell under pressure (edge bending stress).


The stress in the red zone attains 240 MPa. It is due to the fixed nodes close to the curvature change.

Location Measured FEM Computed [MPa] [MPa] [MPa]

Gauge 5-6 125 143 143Gauge 7-8 65 144 too close to the filletGauge 3-4 102 142 143

Fillet / 240 /deflection 2.2 mm 1.8 mm /

Deformation and stress values are comparable with those measured on a prototype with strain gauges:


0

5 0

1 0 0

1 5 0

2 0 0

0 . 2 0 . 4 0 . 6 0 . 8

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

0 . 2 0 . 4 0 . 6 0 . 8

R

Z

R ( m ) [ m ] ( m )

R ( m )

[ M P a ]

[ M P a ]

Equivalent von Mises Stress in MPa on external and internal window faces


1.6 Result for Load Case 2 : P=0.1 MPa

Location of equivalent von Mises Stresses

Stress values in

MPa

Safety Factor wrt UltimateTensile

Strength

Safety Factor wrt Yield Strength

R=715 mm 80 5.7 3.5

R= 654 mm 54 8.0 5.2

0<R<194 47 8.5 5.9

Conclusions : Good agreement between analytical and FEM results except for fillet zone which has been modeled in a conservative way. The window is safe according to CERN safety rules.


2. Thermal Analysis

2.1 Assumptions

Transient analysis Run duration 200 days Initial temperature (materials and air) 15°C

2.2 Material properties :

Unit Titanium steel Concrete

Thermal Conductivity Wm-1C-1 7 51.9 1.8

Expansion coefficient C-1 8.70E-06 1.15E-05 2.10E-06

Density kg m-3 4700 7850 2300Young Modulus GPa 105 200 3.00E+09Poisson ratio --- 0.34 0.3 0.1

Thermal Capacity J Kg-1C-1 525 472 1000

Diffusivity m2/s 2.84E-06 1.40073E-05 7.83E-07


2.3 Boundary Conditions:• Case 3 : Natural convection :

• temperatures : Air 15 °CWindow 22 °C

Free convection coefficient:

• Case 4 : Natural and forced convections : Pipe diameter 12 mm Water temperature 15 °C Flow rate 10 l/mn

Forced convection coefficient:

12n KWm 3h

123f KWm 1013h


2.4 Loading Constant heat Generation:~30 W in the window~430 W in the flanges

0 10 20 30 40 50 60 70 80 90 100 110 120 10

-7

10 -6

10 -5

10 -4

Energy deposition in the Ti-window and in the flange

Ti-window

Fe-flange

GeV

cm

-3/p

r in cm

Power distribution per unit volume

0

5000

10000

15000

20000

25000

30000

35000

0 100 200 300 400 500 600 700 800 900 1000 1100

Radius [mm]h

eat

dep

osi

tio

n in

W/m

3

Proton Flux Density :

1 GeV = Joule

s/p108 1210106.1


2.5 Results2.5.1 Case 3 (free convection)

tem

péra

ture

[°C]

1 765432 temps [jours]

1

C

A

B

47

2

5

6

8

D

A : windowB : mating flangeC : cooling pipeD : flangeE : ConcreteNumbers show measuring points location 9

E


temps [j]0 3 6t = 0, arrêt du faisceau

tem

péra

ture

[°C

]

Temperature evolution during 10 days of cooling time


0.1 0.90.70.50.3rayon [m]

tem

péra

ture

[°C

]

20

30

40

50

Static Stress [MPa]

Thermal Stress [MPa]

Global Stress [MPa]

Safety Coefficientwrt Yield

Strength limit

Safety Coefficient

wrt Ultimate Tensile strength

90 40 130 2.15 3.5

Stresses close to the fillet


2.5.2 Case 4 (free and forced convections)

1 2 3 4te

mp é

r atu

re [

°C]

temps [h]

Temperature rising time : 4 hours

Maximum temperature on window apex : 32°C

Good efficiency of the water cooling for the flanges and weak impact on window temperature


0.1 0.3 0.5 0.7 0.9

tempé

ratu

re [°

C]

rayon [m]

0 0.5 1 1.5 temps [h]

tem

pératu

re [

°C

]

Temperature evolution during 2 hours cooling time

Window and Flange Temperature profiles


3.Thermal and Mechanical Stresses

Static Stress [MPa]

Thermal Stress [MPa]

Global Stress [MPa]

Safety Coefficientwrt Yield Strength

Safety Coefficient

wrt UltimateTensile

Strength

90 8 100 2.8 4.6


3.1 CODAP Verification

point R Top Middle BottomA 0 142 137 142B 194 142 138 142C 654 181 142 103D 703 76 142 201E 715 5 142 272

181 142 272300 200 300

1.66 1.41 1.10

Maximum Stress

Allowable Stress

Shell Stress [MPa] :

Safety Factor

Test Pressure : P=0.3 MPa

Service Pressure : P=0.1 MPa

point R Top Middle BottomA 0 47 46 47B 194 47 46 47C 654 60 47 34D 703 25 47 67E 715 2 47 91 SF

60 47 91 2.54

100 88 132

1.74

68 55 100

2.30

230 153 230Allowable Stress

Shell Stress[MPa]

Maximum structural Maximum Stress Thermal Natural

ConvectionMaximum Stress Thermal Forced

Convection


4. Thermal Shock

Full beam on the window : 3.5x1013 p/pulse

=> 3.34x1018 p/s


0.00E+00

5.00E+11

1.00E+12

1.50E+12

2.00E+12

2.50E+12

3.00E+12

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

zone par tranche de 1 mm [0;1], [1;2], ...

géné

ratio

n de

cha

leur

[W/m

3 ]

After 2 pulses with q=2.6x1012 W/m3

T = 22 °C


After 1 pulse 10.5 s with q=2.6x1012 W/m3

T = 11 °C

Dynamic stress negligible

0

2

4

6

8

10

12

0 5 10 15 20

Rayon [mm]

tem

péra

ture

[°C]


5. Conclusions:

Free Convection inefficient in a CONFINED SPACE => Thermal stresses : 40 MPa on the window 230 MPa on decay tube / concrete interface

With the cooling system : Temperature stabilised at 32 °C, very low thermal stresses

In the event of the beam missing the target, the interlock shall react in less than 1’.

The window is safe according to CODAPSee Technical Note EST-ME/2001-007 EDMS n°323691

r.valbuena nbi 14-19 march 2002 cngs decay pipe entrance window structural and thermal analysis...

Documents

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c slide

ps slide

fullfilled slide

mpa service pressure

valbuena cernest

mpa test pressure case

allowable stress