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Cross-section of the 150 mm aperture case. Paolo Ferracin. HiLumi WP3 Video-meeting 26 July, 2012. Outline. Design concept Conductor properties Magnet parameters Stress analysis Some additional considerations. From HQ to MQXF Magnetic design concept. HQ. MQXF. - PowerPoint PPT Presentation
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Cross-section of the 150 mm aperture case
Paolo Ferracin
HiLumi WP3 Video-meeting26 July, 2012
Outline
• Design concept
• Conductor properties
• Magnet parameters
• Stress analysis
• Some additional considerations26/07/2012Paolo Ferracin 2
From HQ to MQXFMagnetic design concept
• Aperture: from 120 mm to 150 mm • Cable width: from 15 mm to 18 mm wide cable• 2 layers with similar angles and 4 blocks• All harmonics below 1 unit at 2/3 of Rin and 80% of Iss
• Similar iron geometry, but with OD from 520 mm to 558 mm
26/07/2012Paolo Ferracin 3
HQ MQXF
From HQ to MQXFMechanical design concept
• Same support structure concept as HQ• Same shell thickness, but OD from 570 mm to 608 mm • Cooling holes and busbar slots added • 10 mm thick LHe vessel included within 630 mm OD
26/07/2012Paolo Ferracin 4
HQ MQXF
Conductor properties• From 0.80 to 0.85 mm strand• Cu/Sc ratio: 1.13 (53% Cu)
• Assumption on Jc– 2500 A/mm2 at 12 T– 1400 A/mm2 at 15 T
• Resulting Jc for computations with self field correction– 2650 A/mm2 at 12 T– 1450 A/mm2 at 15 T
• Values consistent with D. Dietderich and H. Felice presentation and with FRESCA2 PIT strand data
26/07/2012Paolo Ferracin 5
Cable and coil parameters
• From HQ to MQXF– Wider cable– Increased insulation– 43% more conductor
26/07/2012Paolo Ferracin 6
Units HQ MQXF
Strand # 35 40
Width mm 15.150 18.273
Thickness in/out mm 1.338/1.536 1.396/1.604
Keystone angle 0.75 0.65
Insulation thickness mm 0.100 0.150
Mid-plane insulation mm 0.150 0.250
Interlayer insulation mm 0.250 0.500
Turns per oct. 20 + 26 = 46 23 + 28 = 51
Area supercond. per oct. mm2 380 544
HQ MQXF
Magnet parameters at 1.9 K
26/07/2012Paolo Ferracin 7
Units HQ MQXF
Temperature K 1.9 1.9
Gradient T/m 170 140
Iss % % 81 80
Current kA 14.9 16.8
Peak field T 11.8 12.2
Stored energy MJ/m 0.86 1.41
Stored energy / A ins_cable J/cm3 93 104
Jo A/mm2 593 503
JSc A/mm2 1802 1575
JCu A/mm2 1598 1397
Differential inductance mH/m 7.10 8.68
HQ MQXF
Magnet parameters at 1.9 K
• Comparison with expectations – see “Proposal for aperture”, E. Todesco, 02/07/2012
26/07/2012Paolo Ferracin 8
MQXF expect. MQXF MQXF-HQ
expect. MQXF-HQ
Units
Current kA 16.3 16.8 +12% +13%
Stored energy MJ/m 1.34 1.41 +56% +64%
JSc A/mm2 1485 1575 -18% -6%
Stress MPa 136* 150/129** +6% +10/+8%
* Analytical peak stress on mid-plane** FEM peak stress (1.9 K / Gnom)
Fringe field
• At 5 mm from the cryostat, fringe field ranging from 3 mT for HQ to 8 mT for MQXF
26/07/2012Paolo Ferracin 9
HQ MQXF
Stress analysis
• Lorentz stress on mid-plane – IL: -101 MPa– OL: -121 MPa
• Bladder press. / interf.– 17 MPa / 0.160 mm
• Max shell stress: 150 MPa
• Lorentz stress on mid-plane – IL: -113 MPa– OL: -122 MPa
• Bladder press. / interf.– 27 MPa / 0.430 mm
• Max shell stress: 230 MPa
26/07/2012Paolo Ferracin 10
HQ MQXF
Stress analysisCoil peak stress
26/07/2012Paolo Ferracin 11
HQ @ Gnom
-119 MPa
MQXF @ 1.9 K-150 MPa
MQXF @ Gnom
-129 MPa
HQ @ 1.9 K-137 MPa
Some additional considerations on MQXF (I)
• Coil optimization– Alternative solution with 53 turns
• +2 in outer layer
– Sharp wedge and 1 unit of b14
– But….• 1% of additional margin wrt. Iss
• 2% reduction of JO
– Reduction of few (4-5) MPa of Lorentz stress on mid-plane (IL)
• But smaller effect coil peak stress during operation (work in progress)
26/07/2012Paolo Ferracin 12
51 turns
53 turns
Some additional considerations on MQXF (II)
• Cooling holes– 80 mm diameter
• Could be increased to 90 mm, depending on axial support system
• Busbar– 20 x 50 mm slot
• Axial support– 32 mm axial rods
• Some space for end-plate and pad-bolts
• High stress but probably still fine
– Alternative: end-plate welded to vessel
26/07/2012Paolo Ferracin 13
Some additional considerations on MQXF (III)
• LHe vessel– 10 mm thick cylinder
• OD: 630 mm
– 1 mm gap between vessel and Al shell (nominal dimension)
• About 0.500 mm clearance after pre-loading, cool-down, and excitation
– Still to be verified the welding procedure
• Other modifications/simplifications– Round collars?– No masters?
26/07/2012Paolo Ferracin 14
MQXF
Conclusions• Preliminary analysis of MQXF design based on HQ-concept
– 150 mm aperture, wider cable, OD 630 mm
• MQXF can generate a gradient of 140 T/m with 20% margin at 1.9 K
• 65% higher stored energy than HQ, but similar stored energy density and lower J0
• About 10 MPa higher coil peak stress (from 140 to 150 MPa)– Support structure within stress limits
• Further optimization of coil and structure in progress
26/07/2012Paolo Ferracin 15
Appendix
26/07/2012Paolo Ferracin 16
Stress analysisComparison at 80% of Iss
• From HQ to MQXF_15mm– IL Lorentz stress: +13%– Peak stress: +15 MPa
• From MQXF_15mm to 17mm– Reduction of 10 MPa in peak
stress
26/07/2012Paolo Ferracin 17
Units HQ MQXF_15 mm MQXF_17 mm
IL OL IL OL IL OL
Lorentz stress MPa -100 -120 -113 -128 -108 -128