1. Dump Core Studied Design Solutions
Francois-Xavier Nuiry
Giulia Romagnoli
Tobias Polzin
Edouard Grenier Boley
With the support of EN-MME

2. Design Driving Parameters
Parameters to consider in the core housing design:
Project constraints
Material sandwich selected in FEM simulations
Cooling need
Vacuum requirements
Geometrical constraints
Minimize weight
Radiations
Fatigue
Ti6Al4V housing
14 Ti6Al4V blocks
6 NiCr blocks
BEAM
3 solutions proposed keeping the same core sandwich geometry:
Tube soldered on housing surface
Boite a eau with drilled channels in housing
3D printing solution
12/10/2016
PS Internal Dump Core Review

3. PS Internal Dump Core Review
Proposed Designs
BRAZED TUBES
DRILLED CHANNELS (Boite a Eau)
3D PRINTING
6 seamless cooling circuits brazed to housing
Ti tubes to avoid brazing problems due to CTE mismatches
Square tubes to improve the brazing thermal conductivity
Ti housing for mechanical assembly of blocks
9 channels gun-drilled inside Ti housing
Vacuum compatibility to be checked
Good thermal contact (only 1 brazing)
Ti caps EBW to close the cooling circuit
15 parallel channels 3D printed with housing
Cooling circuit efficiency high (1 brazing joint)
Seamless circuit inside vacuum
Ti housing with minimized thickness
12/10/2016
PS Internal Dump Core Review

4. VSC Group Requirements
Summary of vacuum specifications EDMS :
Materials selected to be agreed with VSC
Welding: 100% penetration
Pressure test with 100% helium at P ≥ water pressure
No grinding or mechanical abrasions
Room temperature leak rate > 2 x Pa m3 s-1 is unacceptable
All surface should be cleaned and degreased according to CERN EDMS document
PS DUMP Project:
Maximum outgassing level: not defined
No need of bake-out (?)
Pressure test (with 100% helium at P ≥ water pressure)
Leak test
VDAM meeting with VSC on the 21st Sep 2016
12/10/2016
PS Internal Dump Core Review

5. Ti Housing to Blocks Connection
Foreseen connecting method:
Vacuum brazing of the blocks to the housing
Design developed together with EN-MME-FW
Single Ti block
Grooves on circular surface to insert the brazing wire
Pocket on the side to guarantee the 1 mm gap for mechanical deformation
Degassing hole for pumping in vacuum
Degassing holes not aligned in beam axis!
First brazing test on going…
Brazing procedure validation in the following weeks!
CDD numbers:
PS_TDIL_0009
PS_TDIL_0010
12/10/2016
PS Internal Dump Core Review

6. Baseline Design of Ti Housing
Design aspects common to the 3 design solutions:
Ti housing open at the bottom to reduce mass and avoid beam interactions
No water channels in the lower dump region to avoid beam interactions
2 Ti wings to equilibrate the weight and cover beam area during ralentisseur mode
Accidental beam ( protons) 1 pulse
ΔT in the water: °C
Half-model used in thermal simulation presented afterwards
6 NiCr blocks
14 Ti6Al4V blocks
Depending on the design proposed the Ti housing can be:
active (part of the cooling system)
passive (acting just as mechanical assembly)
12/10/2016
PS Internal Dump Core Review

7. 1st Design: Tube Soldered on Housing
6 seamless cooling circuits to be soldered to the Ti6Al4V housing:
Parallel circuits to improve the cooling efficiency
Ti tubes to avoid brazing problems due to CTE mismatches
Square tubes to improve the brazing thermal conductivity
Ti housing passive used for mechanical assembly of blocks
Light assembly (4.1 kg)
Design based on the collimators cooling design
Standard solution for the vacuum acceptance
No water to vacuum connections inside vacuum
Cooling circuit efficiency reduced (2 brazing joints)
Ti housing with minimized thickness
12/10/2016
PS Internal Dump Core Review

8. Tube Design Detailed Design
6 parallel channels (4 mm Ø, 500 mm long)
2.1 mm minimum wall thickness
No connection in vacuum
Total length of each cooling circuit ~1500 mm
Longueur « cooling pipe 1 » : 1322mm
Longueur « cooling pipe 2 » : 1454mm
Longueur « cooling pipe 3 » : 1548mm
Longueur « cooling pipe 4 » : 1426mm
Longueur « cooling pipe 5 » : 1464mm
Longueur « cooling pipe 6 » : 1488mm
Design on going…
12/10/2016
PS Internal Dump Core Review

9. Tube Design Thermal Simulation
6 tubes: (7x7 mm with Ø 4 mm, 500 mm long)
Brazing joint between tube and housing
Brazing joint between blocks and housing
No degassing holes and wire grooves
ANSYS MODEL for Thermal Simulations
12/10/2016
PS Internal Dump Core Review

10. PS Internal Dump Core Review
2nd Design: Boite a Eau
Boite a eau: 9 channels gun drilled inside the Ti housing
Parallel channels for cooling efficiency
Ti wings welded + Ti caps to close the cooling circuit
Stainless steel shaft soldered to housing
Vacuum compatibility to be validated and discussed
Good thermal contact (only 1 brazing)
Ti housing active (cooling inside)
Simpler mechanical design
Heavier assembly (5.8 kg)
Design based on the Slit Assembly for Linac 4
Stainless steel shaft
Ti housing with embedded cooling circuit
Ti cap to close the cooling circuit
Ti6Al4V blocks
Rene 41 (NiCr) blocks
Ti wing to cover the beam area
12/10/2016
PS Internal Dump Core Review

11. Boite a Eau Detailed Design
EBW cap to housing
Brazing of Ti to block
Brazing of SS shaft to housing
Design on going…
Design details under discussion…
12/10/2016
PS Internal Dump Core Review

12. Boite a Eau Design Thermal Simulation
Model used in thermal simulations:
9 parallel channels (5 mm Ø, 500 mm long)
2.5 mm minimum wall thickness
ANSYS MODEL for Thermal Simulations
Half-model used in thermal simulation presented afterwards
12/10/2016
PS Internal Dump Core Review

13. 3rd Design: 3D Printing
15 parallel Ti channels 3D printed with the housing:
Parallel circuits to improve the cooling efficiency
Cooling circuit efficiency high (1 brazing joint)
Ti housing active (cooling inside)
Seamless circuit inside vacuum
Ti housing with minimized thickness
Ti wings in the center of the dump
Central blocks in traditional machined materials
Light assembly (4 kg)
Design challenges:
Material porosity
Wall thickness between cooling channels and vacuum
Mechanical fatigue
Thermal fatigue
Water erosion
Particle damage fatigue
Dynamical response of the target
Test pieces produced to validate the design
Cut in half for 3D printing machine size
NO welds in cooling circuit!
12/10/2016
PS Internal Dump Core Review

14. 3D Printing Design Thermal Simulation
Model used in thermal simulations:
15 parallel channels (5 mm Ø, 500 mm long)
2.3 mm minimum wall thickness
ANSYS MODEL for Thermal Simulations
Half-model used in thermal simulation presented afterwards
12/10/2016
PS Internal Dump Core Review

15. Need of Cooling System ACCIDENTAL SCENARIO Protons 26 GeV 5 1013
σ = 1.8x4.7 mm
Pulse time 2.1 µs
Pulse period 2.4 s
3 pulses
SFTPRO BEAM
Protons
14 GeV
2 1013
σ = 2x3.7 mm
Pulse time 2.1 µs
Pulse period 1.2 s
2 pulses then cooldown time of 15 s
LHC 25ns BEAM
Protons
26 GeV
σ = 1x4.7 mm
Pulse time 2.1 µs
Pulse period 3.6 s
5 pulses then cooling down time of 20 s
Beam scenarios considered during simulations
T amb
Time T
T max
Cooling Time
T start
Example of SFTPRO beam temperature profile
Not in scale
T start = T amb ideal configuration
Cooling system necessary?
12/10/2016
PS Internal Dump Core Review

16. PS Internal Dump Core Review
Steady State
LHC 25ns BEAM after 5 pulses and 20 s of cooling down time
Tmax=84°C
Tmax >> Tinitial
COOLING NECESSARY! simulations to check the steady state temperature TSS with a defined cooling system
Time T
Steady state temperature
X time
T amb
TSS < critical temperature for material
Temperature distribution in the material at the SS + some cycles to check:
stress in steady state << critical stress for the material
12/10/2016
PS Internal Dump Core Review

17. Preliminary Thermal Analysis
Thermal simulations assumptions:
LHC25 ns beam scenario considered for thermal simulations
Symmetrical half model
Convection coefficient in the water tubes of 6000 W/m2C  analytical calculations done with conservative mass flow
Thermal conductance of brazed joints 1000 W/m2C  conservative value
STEADY STATE thermal simulation: power distributed over the cycle time (38 s)
TRANSIENT ANALYSIS up to 1 h to check max temperature
Study the cycle averaged temperature increase during 1 h dumping
Intensity
Real intensity deposed during beam impact
Averaged intensity deposition used in steady state simulations
5 Pulses
Cooling Time 20 s
Time
LHC25ns Cyles 38 sec
12/10/2016
PS Internal Dump Core Review

18. PS Internal Dump Core Review
Thermal Simulations
BRAZED TUBES
DRILLED CHANNELS (Boite a Eau)
3D PRINTING
Steady State Tmax: 496 °C
Steady State Tmax: 315 °C
Steady State Tmax: 300 °C
PRELIMINARY RESULTS
3D printing and boite a eau more efficient then tube solution
For boite a eau and 3D printing the max temperature is reached after 12 min
12/10/2016
PS Internal Dump Core Review

19. PS Internal Dump Core Review
3 Designs Pros and Cons
BRAZED TUBES
DRILLED CHANNELS (Boite a Eau)
3D PRINTING
Cooling circuit efficiency high (1 brazing joint)
Seamless circuit inside vacuum
Ti housing with minimized thickness
Light assembly (11.6 kg)
To be checked:
Material porosity
Wall thickness leak tightness
Mechanical fatigue
Thermal fatigue
Water erosion
Particle damage fatigue
Standard for the vacuum acceptance
Seamless circuits inside vacuum
Ti housing minimized thickness
Light assembly (11.7 kg)
Complex mechanical assembly
Cooling circuit efficiency reduced (two brazing joints)
Good thermal contact (only 1 brazing)
Simple mechanical design
EBW in vacuum
Heavier assembly (13.4 kg)
Ti housing bigger
12/10/2016
PS Internal Dump Core Review

20. PS Internal Dump Core Review
Conclusions
3 solutions proposed for the PS dump housing design
The final design is not selected yet, further tests are needed:
Thermal and mechanical analysis for maximum temperature and stress evaluation
Cooling system detailed design
3D printing investigation tests
Design requirements fulfillment
12/10/2016
PS Internal Dump Core Review

21. PS Internal Dump Core Review
Thank you!
12/10/2016
PS Internal Dump Core Review