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ITS Ultr a-low-Mass Cooling System Pipe Design: Minimum Inner D iameter calculation & Constructive Considerations. Enrico DA RIVA Manuel GOMEZ MARZOA CFD Meeting - 25 th January 2013. Contents. Overview Cooling system: constraints Cooling concepts Pipes per stave - PowerPoint PPT Presentation
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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. Overview2. Cooling system: constraints3. 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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CFD Meeting - 25th January 2013 3
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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CFD Meeting - 25th January 2013 4
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 mmb) Squeezed pipesc) 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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CFD Meeting - 25th January 2013 7
T3
T3
T2 = T1+0.5*ΔTStave
Cooling ConceptsPipes per stave
1 straight pipe along each stave:T1
T2Stave
Stave
T1 U-pipe along each stave:
ΔTRef-Stave = T3-T1
ΔTRef-Stave = T3-T1
Inner Barrel
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CFD Meeting - 25th January 2013 8
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
3 U-pipe, leak-less 0.83 0.58 6.0 2.32 0.18<0.20 0.99
4 U-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
6 U-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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Where are we? Outer Barrel
BusSi 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 layer6-7 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:T1
T2Half-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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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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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 BarrelL4-5
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Pipe Inner Diameter Optimization Assumptions:
Stave power density: 0.4 W cm-2
Restrictions: ΔTMax-InOut = 3-6 K Lpipe = 0.85-1.70 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
3 U-pipe, leak-less 1.25 1.70 6.0 7.25 0.18<0.20 2.05
4 U-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
6 U-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 BarrelL4-5
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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 BarrelL6-7
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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
3 U-pipe, leak-less 1.10 3.00 6.0 12.70 0.19<0.20 4.08
4 U-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
6 U-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 BarrelL6-7
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CFD Meeting - 25th January 2013 21
Pipe Inner Diameter Optimization
Layer IDMin [mm] Design Refrigerant ΔTRef [K] vH2O [m s-1]
1, 2, 3 0.55U-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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CFD Meeting - 25th January 2013 25
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