e. da riva/m. gomez marzoa1 cfd meeting - 25th january 2013 its ultra-low-mass cooling system pipe...
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E. Da Riva/M. Gomez Marzoa 1CFD Meeting - 25th January 2013
ITS Ultra-low-Mass Cooling System
Pipe Design:
Minimum Inner Diameter calculation
&
Constructive Considerations
Enrico DA RIVA
Manuel GOMEZ MARZOA
CFD Meeting - 25th January 2013
Contents
CFD Meeting - 25th January 2013 2
1. Overview
2. Cooling system: constraints
3. Cooling concepts
Pipes per stave
Operating pressure
4. Pipe Inner Diameter optimization
Inner Barrel layers
Outer Barrel layers
5. Construction of the tubing
Material
Erosion constraints
U-pipe construction
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OverviewInner Barrel Outer Barrel
Wound-truss structure.
Wound-truss structure with high-conductivity plate.
Concept for outer layers (4-5, 6-7), based on the high-conductivity plate cooling idea.
x/X0 < 0.3% per layer x/X0 < 0.8% per layer
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1. Refrigerant maximum velocity:
Avoiding failure by erosion.
Minimizing pressure drop.
No specific recommendations found for such small plastic pipe:
ASHRAE Handbook: not exceeding 1.5 m s-1 would minimize effects of erosion.
Catheters use similar pipes and materials.
8.5 French gauge catheter (2.8 mm OD, ~1.5 mm ID) cordis/introducer 1.
Max. flow rate: 126 mL min-1 = 7.56 L h-1 = 1.18 m s-1
Max. flow rate w/ p. bag @300 mmHg: 333 mL min-1=19.98L h-1 = 3.1 m s-1
Damage by erosion in a plastic pipe could be roughly estimated by assessing the material
hardness and compared to that of a regular copper pipe (but degradation?).
2. Admissible pressure drop:
Single-phase cooling: depends on the cooling system design.
Two-phase cooling: must be kept low to ensure the minimum ΔTSat across stave.
3. Admissible ΔTRefrigerant across stave:
Related to stave temperature uniformity.
In a two-phase cooling system, should not decrease a lot (risk of going below dew point).
Cooling system: constraints
1 Source: http://emupdates.com/2009/11/25/flow-rates-of-various-vascular-catheters/
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1. No prototype performed OK (0.3 W cm-2)
2. A last prototype with larger winding angle
will be available for test
Where are we? Inner Barrel
1. Successful proposal (up to 0.5 W cm-2)
2. Several prototypes for test:
a) Pipe ID = 1 mm
b) Squeezed pipes
c) K1100 Plate (λ ~ 1000 W m-1 K-1)
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1. Pipe dimensions:
Initially: ID = 1.450, OD = 1.514 mm
Reason: winding CF around pipe without breaking it (wound-truss structure).
Used as well for the wound-truss structure with high conductivity plate.
Pipe ID could be reduced from the refrigerant viewpoint (water/C4F10).
Constructively possible in High-conductivity plate prototype!
Reduced pipe ID prototype: ID = 1.024, OD = 1.074mm: TO BE TESTED!!
Pipe ID optimization: consider:
Different cooling system layouts.
Refrigerants.
Pipe erosion.
2. Pipe material:
So far: only polyimide (Kaption®) has been taken into consideration and used for the
construction of prototypes.
Concerns:
Pipe integrity?
Mechanical stiffness? (in case of making the U-bend without connectors).
…
Where are we? Inner Barrel
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T3
T3
T2 = T1+0.5*ΔTStave
Cooling ConceptsPipes per stave
1 straight pipe along each stave:
T1T2
Stave
Stave
T1
U-pipe along each stave:
ΔTRef-Stave = T3-T1
ΔTRef-Stave = T3-T1
Inner Barrel
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Cooling ConceptsOperating pressure
Water in single-phase flow:
Leak-less mode (p<1 bar): Δp at stave must be kept low!
No connectors: pMax and Δp limited by pipe strength.
C4F10 in two-phase:
Main limitation is ensuring ΔTSat < ΔTSat-Admissible across the stave.
Current design options
1. Water in single-phase or C4F10 two-phase.
2. Leak-less or no connectors.
3. Single pipe or U-pipe per stave.
6 possible designs.
4 with water
2 with C4F10
Goal: assess the minimum pipe diameter for each of these designs.
Assuming reasonable operating conditions and respecting constraints.
Comparing with experimental results.
Inner Barrel
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CFD Meeting - 25th January 2013 9
Pipe Inner Diameter OptimizationWater in single-phase
Assumptions:
Stave power density: 0.4 W cm-2
Water maximum velocity: 1.5 m s-1
1,2. Water, single pipe:
Restrictions:
Single/U-pipe:
ΔTWater = 3-6 K
Lpipe = 0.29-0.58 m
Leak-less/no connectors:
ΔpMax-InOut = 0.2-2 bar
q [W cm-2] Lpipe [m] ΔTWater [K] m [L h-1] vH2O [m s-1] ΔpInOut [bar] ID [mm]
0.4 0.29 3.0 4.65 1.35 0.10<0.20 1.22
3. Water, U-pipe, leak-less:
q [W cm-2] Lpipe [m] ΔTWater [K] m [L h-1] vH2O [m s-1] ΔpInOut [bar] ID [mm]
0.4 0.58 6.0 2.32 0.83 0.18<0.20 0.99
q [W cm-2] Lpipe [m] ΔTWater [K] m [L h-1] vH2O [m s-1] ΔpInOut [bar] ID [mm]
0.4 0.58 6.0 2.32 1.50 1.06<2.00 0.55
4. Water, U-pipe, no connectors:
Inner Barrel
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CFD Meeting - 25th January 2013 10
Pipe Inner Diameter OptimizationC4F10 in two-phase
Assumptions:
Stave power density = 0.4 W cm-2
ΔxInOut = 0.5 (conservative)
xAverage = 0.5 (for Friedel corr.)
5. C4F10, single pipe:
Restrictions:
Single/U-pipe:
ΔTMax-InOut = 3-6 K
ΔpMax-InOut = 0.19-0.37 bar
Lpipe = 0.29-0.58 m
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 0.29 3.0 0.51 1.10 0.10<0.19
6. C4F10, U-pipe:
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 0.58 6.0 0.51 1.13 0.35<0.37
0.4 0.50 0.58 6.0 0.36 0.99 0.36<0.37
Inner Barrel
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Pipe Inner Diameter Optimization
Assumptions:
Stave power density: 0.4 W cm-2
Restrictions:
ΔTMax-InOut = 3-6 K
Lpipe = 0.29-0.58 m
Water vH2O [m s-1] Lpipe [m] ΔTRef [K] m [L h-1] ΔpInOut [bar] ID [mm]
1,2 Single pipe 1.35 0.29 3.0 4.65 0.10<0.20 1.22
3U-pipe,
leak-less0.83 0.58 6.0 2.32 0.18<0.20 0.99
4U-pipe, no connectors
1.50 0.58 6.0 2.32 1.06<2.00 0.55
C4F10 ΔxInOut [-] Lpipe [m] ΔTRef [K] m [g s-1] ΔpInOut [bar] ID [mm]
5 Single pipe 0.35 0.29 3.0 0.51 0.10<0.19 1.10
6U-pipe, no connectors
0.35 0.58 6.0 0.51 0.35<0.37 1.13
The minimum pipe diameter is achieved for design number 4:
ID=0.55 mm ~ 62% smaller than current 1.45 mm ID!
Refrigerant material budget (i.e. water) is 7 times lower!
Inner BarrelSUMMARY
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CFD Meeting - 25th January 2013 12
Where are we? Outer Barrel
Bus
Si 0.05mm thick
Kapton, ID=2.794 mm wall = 0.06mm
30.4 mm
Carbon prepreg thick=TBD
Carbon prepreg thick=TBD
Layer LStave [mm] Si width [mm] q [W cm-2] Q per stave [W] x/X0 [%]
4-5 843 30 0.4 101.2 <0.8 per layer
6-7 1475 30 0.4 177.0 <0.8 per layer
Spaceframe
CF Plate
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T3
T3
T2 = T1+0.5*ΔTHalf-stave
Cooling ConceptsPipes per stave
1 straight pipe along each half stave:
T1T2
Half-stave
Half-stave
T1
U-pipe along each half-stave:
ΔTRef-Stave = T3-T1
ΔTRef-Half-Stave = T3-T1
Outer Barrel
Stave
Half-stave
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CFD Meeting - 25th January 2013 14
Cooling ConceptsOperating pressure
Water in single-phase flow:
Leak-less mode (p<1 bar): Δp at stave must be kept low!
No connectors: pMax and Δp limited by pipe strength.
C4F10 in two-phase:
Main limitation is ensuring ΔTSat < ΔTSat-Admissible across the stave.
Current design options
1. Water in single-phase or C4F10 two-phase.
2. Leak-less or no connectors.
3. Single pipe or U-pipe per stave.
6 possible designs.
4 with water
2 with C4F10
Goal: assess the minimum pipe diameter for each of these designs.
Assuming reasonable operating conditions and respecting constraints.
Comparing with experimental results (not yet).
Outer Barrel
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CFD Meeting - 25th January 2013 15
Pipe Inner Diameter OptimizationWater in single-phase
Assumptions:
Stave power density: 0.4 W cm-2
Water maximum velocity: 1.5 m s-1
1,2. Water, single pipe per half stave:
Restrictions:
Single/U-pipe:
ΔTWater = 3-6 K
Lpipe = 0.85-1.70 m
Leak-less/no connectors:
ΔpMax-InOut = 0.2-2 bar
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 3.0 14.50 1.40 0.85 0.09<0.20 3.66
3. Water, U-pipe per half stave, leak-less:
4. Water, U-pipe per half stave, no connectors:
Outer Barrel
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 6.0 7.25 1.25 1.70 0.18<0.20 2.05
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 6.0 7.25 1.5 1.70 0.32<2.00 1.71
L4-5
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CFD Meeting - 25th January 2013 16
Pipe Inner Diameter OptimizationC4F10 in two-phase
Assumptions:
Stave power density = 0.4 W cm-2
ΔxInOut = 0.5 (conservative)
xAverage = 0.5 (for Friedel corr.)
5. C4F10, single pipe per half stave:
Restrictions:
Single/U-pipe:
ΔTMax-InOut = 3-6 K
ΔpMax-InOut = 0.19-0.37 bar
Lpipe = 0.85-1.70 m
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 0.85 3.0 1.59 2.65 0.10<0.19
6. C4F10, U-pipe per half stave:
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 1.70 6.0 1.59 2.75 0.36<0.37
0.4 0.50 1.70 6.0 1.11 2.40 0.36<0.37
Outer Barrel
L4-5
E. Da Riva/M. Gomez Marzoa
CFD Meeting - 25th January 2013 17
Pipe Inner Diameter Optimization
Assumptions:
Stave power density: 0.4 W cm-2
Restrictions:
ΔTMax-InOut = 3-6 K
Lpipe = 0.85-1.70 m
Water vH2O [m s-1] Lpipe [m] ΔTRef [K] m [L h-1] ΔpInOut [bar] ID [mm]
1,2 Single pipe 1.40 0.85 3.0 14.50 0.09<0.20 3.66
3U-pipe,
leak-less1.25 1.70 6.0 7.25 0.18<0.20 2.05
4U-pipe, no connectors
1.50 1.70 6.0 7.25 0.32<2.00 1.71
C4F10 ΔxInOut [-] Lpipe [m] ΔTRef [K] m [g s-1] ΔpInOut [bar] ID [mm]
5 Single pipe 0.35 0.85 3.0 1.59 0.10<0.19 2.65
6U-pipe, no connectors
0.35 1.70 6.0 1.59 0.36<0.37 2.75
The minimum pipe diameter is achieved for design number 4:
ID=1.71 mm ~ 39% smaller than the ordered 2.794 mm ID.
SUMMARY Outer Barrel
L4-5
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CFD Meeting - 25th January 2013 18
Pipe Inner Diameter OptimizationWater in single-phase
Assumptions:
Stave power density: 0.4 W cm-2
Water maximum velocity: 1.5 m s-1
1,2. Water, single pipe per half stave:
Restrictions:
Single/U-pipe:
ΔTWater = 3-6 K
Lpipe = 1.5-3.0 m
Leak-less/no connectors:
ΔpMax-InOut = 0.2-2 bar
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 3.0 25.40 1.50 1.50 0.09<0.20 5.98
3. Water, U-pipe per half stave, leak-less:
4. Water, U-pipe per half stave, no connectors:
Outer Barrel
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 6.0 12.70 1.10 3.00 0.19<0.20 4.08
q [W cm-2] ΔTWater [K] m [L h-1] vH2O [m s-1] Lpipe [m] ΔpInOut [bar] ID [mm]
0.4 6.0 12.70 1.50 3.00 0.47<2.00 2.99
L6-7
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CFD Meeting - 25th January 2013 19
Pipe Inner Diameter OptimizationC4F10 in two-phase
Assumptions:
Stave power density = 0.4 W cm-2
ΔxInOut = 0.5 (conservative)
xAverage = 0.5 (for Friedel corr.)
5. C4F10, single pipe per half stave:
Restrictions:
Single/U-pipe:
ΔTMax-InOut = 3-6 K
ΔpMax-InOut = 0.19-0.37 bar
Lpipe = 1.50-3.00 m
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 1.50 3.0 2.78 4.25 0.09<0.19
6. C4F10, U-pipe per half stave:
q [W cm-2] ΔxInOut [-] Lpipe [m] ΔTRefrig [K] m [g s-1] ID [mm] ΔpInOut [bar]
0.4 0.35 3.00 6.0 2.78 4.35 0.35<0.37
0.4 0.50 3.00 6.0 1.94 3.80 0.36<0.37
Outer Barrel
L6-7
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CFD Meeting - 25th January 2013 20
Pipe Inner Diameter Optimization
Assumptions:
Stave power density: 0.4 W cm-2
Restrictions:
ΔTMax-InOut = 3-6 K
Lpipe = 1.50-3.00 m
Water vH2O [m s-1] Lpipe [m] ΔTRef [K] m [L h-1] ΔpInOut [bar] ID [mm]
1,2 Single pipe 1.50 1.50 3.0 25.40 0.09<0.20 5.98
3U-pipe,
leak-less1.10 3.00 6.0 12.70 0.19<0.20 4.08
4U-pipe, no connectors
1.50 3.00 6.0 12.70 0.47<2.00 2.99
C4F10 ΔxInOut [-] Lpipe [m] ΔTRef [K] m [g s-1] ΔpInOut [bar] ID [mm]
5 Single pipe 0.35 1.50 3.0 2.78 0.09<0.19 4.25
6U-pipe, no connectors
0.35 3.00 6.0 2.78 0.35<0.37 4.35
The minimum pipe diameter is achieved for design number 4:
ID=2.99 mm ~ 6.5% bigger than the ordered 2.794 mm ID.
SUMMARY Outer Barrel
L6-7
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Pipe Inner Diameter Optimization
Layer IDMin [mm] Design Refrigerant ΔTRef [K] vH2O [m s-1]
1, 2, 3 0.55
U-pipe, no connectors Water 6.0 1.54, 5 1.71
6, 7 2.99
SUMMARY 0.4 W cm-2
MAT. BUDGET CONSIDERATIONS
Achieving the target of 0.3%:
1. Use a two-phase flow.
2. Minimize pipe diameter to reduce
the impact of the refrigerant to
the global material budget.
BUT need to keep thermal
contact between Si and pipe!
Constructive issues when ↓ID
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Construction of the tubing1. General considerations:
Robust: elastic modulus, high burst pressure.
Thin walls: reduce mat. budget.
Compatible with refrigerant (C4F10).
Easy to bend: in case of making a no-connector stave, limited space.
Erosion: related to the material hardness.
2. Specific requirements:
High radiation hardness: minimum damage.
Ageing: physical and chemical stability over time.
Comply to LHC Fire Safety Instruction (IS-41)
Low material budget material (plastics better than metals).
E. Da Riva/M. Gomez Marzoa
1. General considerations:
Robust:
Tensile strength = 117.9 Mpa
Flexural Modulus = 4.1 GPa
Thin walls: down to 0.025 mm for a pipe with 0.55 mm ID
Compatible with refrigerant (C4F10): yes
Easy to bend:
Must avoid kinking failure: when section deforms to an elliptical shape.
A reinforcement braid can be included locally to prevent kinking.
Braid: SS or others, Covered with Nylon, Pebax…
Flexible liners like Nitinol (Ni + Ti) or Kevlar could reinforce the tube to
be bent and preserve the shape (shape memory).
Erosion: related to the material hardness.
Polyimide/PEEK: 87D (Shore D)
PVC Pipe: 89D (Shore D)
Copper: 372 Mpa (Vickers)
CFD Meeting - 25th January 2013 23
Construction of the tubing
Minimum bend
radius?
In Vickers, polyimide would
have 772 MPa
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CFD Meeting - 25th January 2013 24
Construction of the tubing2. Specific requirements:
High radiation hardness: according to CERN-98-01 report, polymide:
No problem below 107 Gy
Mild damage between 107 to 5 107 Gy
1st layer of ITS Inner Barrel will be exposed to 700 krad/yr.=7000 Gy/yr.
Ageing: physical and chemical stability over time.
Plastic Pipe Institute states corrosion is not an issue in plastic pipes.
Comply to LHC Fire Safety Instruction (IS-41)
Polyimide is allowed.
Nylon® (polyamide) is allowed if a fire retardant NOT containing
halogen, sulphur or phosphorus.
Pebax: polyether block amides – “legal” in cavern??
Low material budget material (plastics better than metals).
Polyimide: X0 = 29 cm, minimum wall thickness is 0.025 mm.
PEEK: X0 = 31.45 cm, minimum wall thickness is 0.25 mm.
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Construction of the tubing
Advantages of a PEEK pipe over polyimide:
Low material budget material.
Polyimide: X0 = 29 cm
PEEK: X0 = 31.45 cm
The U-turn can be shaped and retain the shape.
Extremely stable.
More common in scientific applications than polyimide tubing.
Advantages of a polyimide pipe over PEEK:
Higher radiation hardness: according to CERN-98-01 report.
Wall thickness:
Polyimide minimum wall thickness = 0.025 mm.
PEEK minimum wall thickness = 0.25 mm
E. Da Riva/M. Gomez Marzoa
E. Da Riva/M. Gomez Marzoa 26CFD Meeting - 25th January 2013
ITS Ultra-low-Mass Cooling System
Pipe Design:
Minimum Inner Diameter calculation
&
Constructive Considerations
Enrico DA RIVA
Manuel GOMEZ MARZOA
CFD Meeting - 25th January 2013