C.KotnigFCC Design Meeting FCC Beam Screen cooling Claudio Kotnig

C.KotnigFCC Design Meeting Content 1.New Beam Screen Design 2.Beam Screen Cooling – Sector design a)Basic hydraulic scheme b)Header and magnet string design 3.Modifications of the basic hydraulic scheme 4.Transient modes: Beam Injection 5.Summary 2

C.KotnigFCC Design Meeting New Beam Screen Design 3 Small CB C10 Small CB O4 Big CB C8Big CB O4  T ≈ K Antechamber  T ≈ 1 K Thermal comparison of the examined designs Higher temperature range available for extracting the heat → Less mass flow → Less pressure drop → Less exergy losses

C.KotnigFCC Design Meeting New Beam Screen Design 4 Small CB C10 Small CB O4 Big CB C8Big CB O4 A Cap ≈ 68.4 mm 2 A Cap ≈ 26.2 mm 2 A Cap ≈ 9.6 mm 2 A Cap ≈ 1.8 mm 2 A tot ≈ 274 mm 2 A tot ≈ 105 mm 2 A tot ≈ 77 mm 2 A tot ≈ 18 mm 2 Antechamber A Cap ≈ 57.6 mm 2 A tot ≈ 115 mm 2 d hyd ≈ 6.14 mm d hyd ≈ 2.81 mm d hyd ≈ 3.5 mmd hyd ≈ 1.5 mm d hyd ≈ 6.03 mm Hydraulic comparison of the examined designs Hydraulic performance should be between Big CB O4 and Small CB O4

C.KotnigFCC Design Meeting ­ Large controlling effort ­ Investment costs ­ Down time due to component failure ≈ ≈ ≈ Beam Screen Cooling – Sector design 5 FCC sector design: 1.Control Valves +Minimizing total mass flow +Individual control of single magnet strings +High efficiencies and stable operation in non-nominal modes → valves, but minimize necessary amount → Parallel flow scheme with possible advantages compared to counter flow scheme, if no valves would be used 2.Flow direction → counter flow scheme 3.Assembly scheme +Large temperature range available ­ Variable compressor inlet conditions +High pressures in the magnet strings ­ Large valves necessary +High supply pressures → smaller pressure losses +High supply pressures → smaller pressure ratios 4.Supply pressure → supply pressure 50 bar → assembly scheme HX1 - C – HX2 – MS - V

C.KotnigFCC Design Meeting Beam Screen Cooling – Sector design 6 Pressure drop in beam screen and headers is a crucial influence quantity for the necessary electrical power Pressure losses can be reduced with increasing header diameter → high investment costs and necessary space shorter magnet strings → many valves necessary Influence on the exergetic efficiency by variation of these parameters on the hydraulic schemes? Supply pressure p 0 = 50 bar Isentropic efficiency of the (cold) compressor  s = 0.7

C.KotnigFCC Design Meeting Beam Screen Cooling – Sector design 7 Exergetic efficiency  vs. header diameter d H for 1, 4 & 7 magnets per MS

C.KotnigFCC Design Meeting Modifications of the basic hydraulic scheme 8 Example: Distribution of pressure losses in magnet strings (7 magnets) Installing a bypass at the last MS increases the total mass flow deacreases the basic pressure drop in the last magnet string MS inlet temperature increases due to thermal shielding of the supply header m BP = 0.43 kg/s

C.KotnigFCC Design Meeting Exergetic efficiency  vs. bypass mass flow m BP for 1, 4 & 7 magnets per MS Modifications of the basic hydraulic scheme 9  max

C.KotnigFCC Design Meeting Modifications of the basic hydraulic scheme 10 Example: Distribution of pressure losses in magnet strings (7 magnets) → No thermal shielding tasks for the supply header Basic (minimal) pressure drop increases with MS inlet temperature → MS inlet temperature low and almost constant Basic:  p 0 ≈ 8 barBypass:  p 0 ≈ 5.5 bar RH-Shield:  p 0 ≈ 4 bar

C.KotnigFCC Design Meeting Modifications of the basic hydraulic scheme 11 Exergetic efficiency  vs. header diameter d H for 1, 4 & 7 magnets per MS

C.KotnigFCC Design Meeting Modifications of the basic hydraulic scheme 12 Warm compressor cycle (TU Dresden) Depending on pressure drop in the sector, the necessary power consumption including the Nelium-Cycle, could be lower than in a cold compressor cycle A warm compressor is less prone to failure and easier to handle A warm compressor could be used for cool- down and warm-up tasks A warm compressor could have advantages regarding load changes (e.g. inserting the beam after working a long time in standby mode, etc. ) Warm compressor cycle TaTa Cold compressor cycle Nelium cycle

C.KotnigFCC Design Meeting Exergetic efficiency  vs. header diameter d H for 1, 4 & 7 magnets per MS Modifications of the basic hydraulic scheme 13

C.KotnigFCC Design Meeting  s = 0.7 (cold compressor)  s = 0.83 (warm compressor)  th = 0.42 (Nelium cycle) Modifications of the basic hydraulic scheme 14 Beam screen sector cycle + Nelium cycle Shield 1M Shield 4M Shield 7M Bypass 4MBypass 7MBypass 1M Basic 1M Basic 7M Basic 4M 1 MW ≙ 36,000,000 CHF in 10 years of FCC operation 1) 2) 3)

C.KotnigFCC Design Meeting Modifications of the basic hydraulic scheme # magnets per string477 # valves13879 total mass flow5.68 kg/s5.08 kg/s bypass mass flow0.15 kg/s (≈ 2.6 %)-- temperature last MS inlet44.6 K≈ 40 K pressure drop last MS2.02 bar3.84 bar pressure drop / ratio2.8 bar / bar / 1.10 total power consumption8.3 MW8.4 MW9.2 MW additional pipingyes warm compressor benefitsno yes temperature HX inlet60.0 K62.5 K ? ?

C.KotnigFCC Design Meeting Transient modes: Beam injection 16 Similar increase of current like in the LHC → standby to nominal operation in 27 minutes

C.KotnigFCC Design Meeting Transient modes: Beam injection 17 Fast increase of heat to extract (especially at the end of the injection process) → during normal physic’s runs the working point of the compressor shall be kept constant artificially Only during longer breaks, the load on the compressor shall be decreased Starting physic’s runs again → reach working point by closing valves before magnet ramping starts T in = const. p in = const. m = const.

C.KotnigFCC Design Meeting Summary 18 Summary The pressure drop generated in the sector is the crucial quantity for the necessary electrical power – the design of the hydraulic scheme is decisive for the final pressure drop. Based on the actual sector design, hydraulic schemes with a cold compressor are the better choice w.r.t. the power consumption. Warm compressors have advantages like multipurpose usage and easier handling. The investigation of transient processes could bring the choice regarding the type of used compressor to a head, if one concept clearly is superior during transient modes. The separate shielding scheme is the preferable choice to minimize the necessary power consumption for cooling magnet strings of reasonable lengths.

C.KotnigFCC Design Meeting Thank you very much for your attention

C.KotnigFCC Design Meeting New Beam Screen Design 20 New Beam Screen Design developed by the VCS-Group at CERN Shield (Antechamber) Beam Tube Capillaries Copper layer(s) Cold Bore 41

C.KotnigFCC Design Meeting New Beam Screen Design 21 Heat loads affecting the Beam Screen: 28.4 W/m (synchrotron radiation) 3 W/m (resistance image current) o Small dispersion angle (≈ 10º) o Large component in axial direction → parts affected by the synchrotron radiation depend on the reflection and the distances between the stabilizing ribs o Only one direction o Heat transition via weld contacts

C.KotnigFCC Design Meeting New Beam Screen Design 22 ≈ 56 K < 41 K 40 K Temperature difference < 1 K (former designs: ≈ K) → Larger temperature difference available less exergy losses less mass flow

C.KotnigFCC Design Meeting Beam Screen Cooling – Sector design 23 Solutions for provide compressor with constant inlet conditions Second HXBypass +Low investment costs and necessary space ­ High investment costs and necessary space +Possibility of using different temperature levels ­ Temperatures clearly below 40 K necessary

C.KotnigFCC Design Meeting Basic Beam Screen Cooling System 24

C.KotnigFCC Design Meeting Modifications of the Basic Beam Screen Cooling System 25

C.KotnigFCC Design Meeting Modifications of the Basic Beam Screen Cooling System 26

C.KotnigFCC Design Meeting Modifications of the Basic Beam Screen Cooling System 27