J. Garca, F. Toral Electrical Engineering Unit Department of Technology July, 17 th 2014 Magnet and cable specifications. Magnetic design. Mechanical design. Radial inward forces. Large radial collar deformation. Large azimuthal coil displacements. Next developments. Manufacturing & scheduling. 2 Magnet and cable specifications 3 Combined Dipole (Operation in X-Y plane) Minimum free aperture > 150 mm Working temperature = 1.9 K Integrated field = 2.5 Tm Magnetic length 1.2 m Working Point = 65% Field Quality = Multipoles below 10 units. Iron: Same heat exchanger holes as MQXF. Desirable features: Larger operational field (up to 3T). Shorter coil ends 4 Strand parameters Cu:Sc1.75- Strand diameter0.48mm Metal section0.181mm 2 N of filaments2300- Filament diam.6.0m I(5T,4.2K) * (prev. 203) A Jc * (prev. 3085) A/mm 2 Cable Parameters No of strands18- Metal area3.257mm 2 Cable thickness0.845mm Cable width4.370mm Cable area3.692mm 2 Metal fraction Key-stone angle0.67deg Inner Thickness0.819mm Outer Thickness0.870mm * Extracted from strand March-14 Insulation: Option A: Fiber glass Option B: Polyimide Insulation: 2 x 25m + 55 m (in stock at CERN) 5 Extrapolation would be enough Magnetic Design 7 8 Single LayerDouble Layer 9 dl R d=2Rcos I IC -I IC B OC J[A/m]=J 0 cos T R R h F F * * Linear Iron Inner coil (IC) & Outer Coil (OC) parameters Units Single layer design Double Layer design (15 mm between coils) Old MCBX (Roxie Series Model, Both coils powered ) Nominal field 100% (IC)T Nominal field 10% (IC)T Non-linearity (IC)% -0.47%-4.84%-7.03% Nominal field 100% (OC)T Nominal field 10% (OC)T Non-linearity (IC)% -0.47%-7.63%-10% Field Increment%033.8%42.72% Nominal current (IC) A x8=4400 Nominal current OC)A x8=4400 Working point%60%61.28%60% Torque using Roxie Forces (IC)10 5 Nm/m Torque using Roxie Forces (OC)10 5 Nm/m Torque using Analytical Eq. (IC)10 5 Nm/m Difference Roxie vs Analytical Eq.%+1.68%+4.176%-1.07% Conductors height (h)mm4.372x (8) Mean radius (IC)m Mean stress at the coil and collar nose interface MPa Aperture (IC)mm150 90 Aperture (OC)mm180200116.8 Iron yoke Inner Diam.mm230250180 Iron yoke Outer Diam.mm540 330 Number of conductors used (1 st quad) Inner coil (IC) & Outer Coil (OC) parameters Units Single layer design Double Layer design (15 mm between coils) Old MCBX (Roxie Series Model, Both coils powered ) Nominal field 100% (IC)T Nominal field 10% (IC)T Non-linearity (IC)% -0.47%-0.61%-1.2% Nominal field 100% (OC)T Nominal field 10% (OC)T Non-linearity (IC)% -0.47%-1.58%-1.67% Field Increment%000 Nominal current (IC) A x8=2900 Nominal current OC)A x8=2650 Working point%60%44.7%39.54% Torque using Roxie Forces (IC)10 5 Nm/m Torque using Roxie Forces (OC)10 5 Nm/m Torque using Analytical Eq. (IC)10 5 Nm/m Difference Roxie vs Analytical Eq.%+1.68%+4.13%-1.099% Conductors height (h)mm4.372x (8) Mean radius (IC)m Mean stress at the coil and collar nose interface MPa Aperture (IC)mm150 90 Aperture (OC)mm180200116.8 Iron yoke Inner Diam.mm230250180 Iron yoke Outer Diam.mm540 330 Number of conductors used (1 st quad) Mechanical Design 12 13 In order to detect the major problems to face in the mechanical design, two simplified models have been used: Material properties used in the simulations: MaterialE [Gpa]u [-]CTE [K -1 ] Coils (Impregnated)NbTi+Cu400, *10 -5 CollarsStainlessSteel K / K 0, *10 -5 SpacersCu K /138 4K 0, *10 -5 Inner tubeTi1300, * D 60deg sectors model 2D Single Coil model 14 As a combined dipole that requires a square range of operation in X and Y axis, a large torque arises when both coils are powered. It is required to mechanically fix the coils somehow in order to guarantee the field quality of the magnet. Other major issues detected with the models were: Radial inward forces. Large deformations Large azimuthal displacements of the coils. Large radial deformation of the assembly (elliptic shape). Apart from the mechanical fixation needed to hold the torque, solutions had to be proposed and tested regarding these issues. 15 Due to the combined dipole configuration, radial inward forces appear in the inner coil (upper blocks), causing the coils to deform into the aperture. Radial deformation Old MCBX N/m 7 MPa 2600 Nm/m Single layer design N/m 5,6 MPa 2700 Nm/m N/m 4 MPa 3200 Nm/m N/m 6 MPa 5750 Nm/m N/m 4.4 MPa 3700 Nm/m N/m 1,65 MPa 1450 Nm/m Double layer design Is there any previous experience about this issue in the old MCBXs? N/m 17 MPa 5000 Nm/m Further magnetic optimization will try to reduce, if possible, the angular dimension of the upper spacers in order to mitigate this effect. Lets compare the radial displacement along this path (1-2) for both parts (the collar and the coil edge) for a magnetic field equal to those obtained with the double layer design collar 2 coil 2 collar 2 coil Why Ti?: It contracts less than steel and coils, so after the cool-down it press the coils outwards and keeping them sticked to the collars. Non magnetic behaviour However Some Ti alloys can be superconductors at low temperatures, so careful material selection will be required. Is there any previous experience available on this issue? Given the best performance of the Ti tube solution, the simulations were focused on this option Lets see the radial displacement using the same path, but now including the inner tube in the model. Loads: -293K->1,9K cooldown + EM forces (Simulating a clearance of 0,05 mm between the inner tube and the coils with a modified K Ti ). 20 Significant effect on the coil displacement!! 21 22 23 Azimuthal Radial Displacement scaling = 13 24 Azimuthal Radial Displacement scaling = 13 Negligible deflection of the tube comparing to the collar displacement Displacement scaling = 13 Combined dipole forces orientation B Considering i.e. a uniformly loaded fixed- ended beam Being h the height of the beam (parallel to q) Considering a collar simplified model (similar loads) F F F F D w The large value of D could explain the large deformations compared with other magnets with similar forces. As F, E and D are fixed by design specifications and material properties, it would be necessary to play with w in order to increase the stiffness of the assembly or limit the displacements using the iron as support 230mm 250mm 28 The radial displacement was studied along the path shown (1-2), being the outer edge of the collars.v 29 Fitting the maximum displacements to something similar to: results in: Double layer case (15mm separation) 30 Simulation with double layer forces!! (same field in the aperture) Displacement scaling = 13 Magnetic mid-plane 32 33 Magnetic mid-plane B 34 B Magnetic mid-plane 35 B Magnetic mid-plane 36 B Magnetic mid-plane 37 B Magnetic mid-plane 38 B Magnetic mid-plane 39 B Magnetic mid-plane 40 B Magnetic mid-plane 41 Greater azimuthal forces accumulation, despite a similar force density: -The coil sector is larger (more than 90, when a conventional dipole has always less than 90) and the extra segment have the greatest forces. -The larger the aperture, the longer the coil length and the total accumulation of forces. VS Magnetic mid-plane 42 Main features: -3D model with collars connected through round keys. -Boundary conditions: -Frictionless support for all front and back faces of collars, keys and coils. -Null displacement and turn of the keys connecting up and down collars with respect to the centre. -All contacts considered frictional, =0.2. Main goals: -Test collars model behaviour. -Achieve coil poles to stick to the collars through azimuthal interference. MaterialE [Gpa]u [-]CTE [K -1 ] CoilsNbTi+Cu400, *10 -5 Collars / KeysStainless Steel K / K 0, *10 -5 43 Measures taken to achieve convergence: -Forcing of 4 elements in Z direction at coils and keys and 2 for collars (half thickness). -Sweep meshing method used in all bodies. -Contact sizing meshing, Relevance=100. -Pre-compression at room temperature at t=1. -Cooldown from 293K to 1,9K at t=2. -Gradual applicationof EM forces from t=2 to t=3. 44 Lets see the azimuthal stress in the mid- plane of the coil along the path shown in the picture (1-2) for a 0,3 mm interference t=2 t=1 t=3 Next developments 45 More versatile and complete model, highly parameterized, including all the solutions previously analysed: Inner tube. Collaring. Azimuthal interference. First simplified, with 60deg sectors, and then with double layer coils. It will be powered with 110% of I N for the mechanical analysis and sizing. 46 Magnetic cross section redesign taking into account: MQXF iron holes configuration Inner tube and final dimensions of the collars. A larger main post is desirable to increase collar assembly rigidity. Reiteration of mechanical design. Coil ends design (after cross section freezing and mechanical design). Quench Simulation: Roxie and CIEMAT code. 47 Manufacturing & scheduling 48 Present needs in term of magnets Preliminary estimation of unit lengths, taken the two layer design as reference. 49 magnetic length [m]units to be installedsparesprototypestotal MCBXFA MCBXFB Unit length [m] inner dipoleouter dipole inner layerouter layerpoleinner layerouter layerpole MCBXFAno splice splice MCBXFBno splice splice Number of unit lengths inner dipoleouter dipole inner layerouter layerpoleinner layerouter layerpole MCBXFAno splice 14 splice14 MCBXFBno splice 25 splice25 Total amount of cable needed = 48 Km. Total amount of strand needed = 865 Km. Short term needs at development phase (with no splices) 50 DateInner dipoleOuter dipoleotherremarks Sep mTests, length already ready in house Nov-141 Mar-152 Jun-15 1 Sep-15 2 Oct-1511 Needs in case of problems for previous coils 51 Cable Insulation: glass fibber sleeve. Fully impregnated coils, radiation hard resin (cyanate-ester blend). Double layer winding, presumably using a ceramic binder treatment as hardener (not fully cured). MilestoneDate End of mechanical 1 st iteration, dealing with main issues End of September / Early October Magnetic design optimization and magnetic cross section freezing End of October End of mechanical 2 nd iterationEnd of November Completion of coil end studyEnd of December / Mid January Winding machine refurbishmentEnd of December Prototype manufacturing milestonesTBD 53 Tests Ceramic binder mechanical properties after 150C treatment and resin impregnation. 54 Annexes 55 Inner coil (IC) & Outer Coil (OC) parameters Units Single layer design Double Layer design (15 mm between coils) Double Layer design (15 mm between coils) Old MCBX (Roxie Series Model, Both coils powered ) Old MCBX (Roxie Series Model, Both coils powered ) Nominal field 100% (IC)T Nominal field 10% (IC)T Non-linearity (IC)% -0.47%-0.61%-4.84%-1.2%-7.03% Nominal field 100% (OC)T Nominal field 10% (OC)T Non-linearity (IC)% -0.47%-1.58%-7.63%-1.67%-10% Field Increment%0033.8%042.72% Nominal current (IC) A x8= x8=4400 Nominal current OC)A x8= x8=4400 Working point%60%44.7%61.28%39.54%60% Torque using Roxie Forces (IC)10 5 Nm/m Torque using Roxie Forces (OC)10 5 Nm/m Torque using Analytical Eq. (IC)10 5 Nm/m Difference Roxie vs Analytical Eq.%+1.68%+4.13%+4.176%-1.099%-1.07% Conductors height (h)mm4.372x (8) Mean radius (IC)m Mean stress at the coil and collar nose interface MPa Aperture (IC)mm150 90 Aperture (OC)mm180200 116.8 Iron yoke Inner Diam.mm230250 180 Iron yoke Outer Diam.mm540 330 Number of conductors used (1 st quad) 57 Faster model building, easy geometry definition. Softer learning curve. Better multiphysics problems workflow. Easy parameterization and design possibilities analysis. Advanced APDL commands can be included also if necessary, combining both tools. It is the future