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LARP Collimator Engineering
E. Doyle 2/3/05
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Review: SS Thermal Simulation• 150mm OD• 25mm wall• Simply supported• Heat: 1hr beam life,
FLUKA results, 10x10x24 rectangular grid mapped to cyl
• I.D. water-cooled 20C– h=11880 W/m^2/C
• No heat transport by water
Cu, 61C
x=221 um
support
support
beam
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• 12/2 meeting: ANSYS Simulation Results– Alternative alloys (Inconel, Invar, Al) yielded
little or no improvement in distortion (assuming uniform cooling of ID)
– Proposed that helical water flow might distribute heat to far side of bar, reducing distortion
• New results– Helical water flow contributes to thermal
distortion by cooling far side of jaw, increasing T through the jaw
– Preferable to cool beam side of jaw only, allow far side to heat up
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• Simulation: Cooling limited to arc centered near beam allows far side of jaw to warm up. Peak temperature higher but distortion less.
• For Cu cylinder, Steady State results:– TSS: 61C => 89C– : 220um => 79um
45 deg arc – 195C, 111C
O.D.
I.D.
SS initial condition
beam
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61C
x=221 m
Spec: 25msupport
support
360o cooling of I.D. 45o cooling arc
89C
x=79 m
Note more swelling than bending
Note transverse gradient causes bending
Note axial gradient
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Mechanical distributor for directing coolant to axial channels
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Distributor & “Hard Wired” coolant channel concepts
Six or more discrete axial flow paths. Individual flexible supply tubes. One or more may be activated for a given rotor orientation. Flow control valves external to vacuum chamber.
Free wheeling distributor – orientation controlled by gravity or external magnetic device – always directs flow to beam-side axial channels whatever the orientation of the rotor.
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Alternative distortion control• Machine jaw with slightly concave
hourglass shape. Thermal distortion => flat• Divide jaw lengthwise in two independent
sections (distortion proportional to L2)• Heat far side of jaw (feedback control?) to
minimize T• Custom alloy combining low-Z high
conductivity with high-Z material
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Designer Alloy Concept
Mat’l Power (kW) per jaw
Tmax (C) Defl (m) Cooled arc
Cu 10.4 61 221 360o
Al 1 3.7 33 143 360o
Al 2219 2 4.6 34 149 360o
Al 2219 2 4.6 43 31 45o
Notes: 1. Pure Al 2. 6% Cu
• Low-Z, high conductivity material matrix with distributed high-Z material
- Cu in Be or Al
- Be is powder metallurgy product. Any ratio is possible.
- 2219 Al: standard alloy with 6% Cu content.
- Investigating higher Cu content alloys
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• 1 hr beam life SS• 4.6 kW heat absorbed• More swelling than bending
2219 Al, cooled on 45o arc of ID
beam
42.7C
x=30.6 m
