FOLLOW UP MEETING - TIDVG 3 - Thermo-mechanical study for future beams

FOLLOW UP MEETING-

TIDVG 3-

Thermo-mechanical study for future beams

C.Maglioni & F.Pasdeloup

with contributions from: R.FOLCH, O.ABERLE, A.P.MARCONE, I.V.LEITAO, F.L.MACIARIELLO

27th August 2014

Outline

2

Reminders Material Limits Heat Exchanges (HE) Pressure profile Thermal study – Results of beam R2_1 Structural study – Results of beam R2_1 Worst Case Conclusion

TED – Beam Parameters

27th August 2014Follow Up Meeting - TIDVG 3 – Thermo-

mechanical study for future beams

Reminders

3

Main Parts (CAD number ST0542558, Drawings SPSTIDVG0001)



Iron Shielding(EN-GJL-200)

Copper jackets(OFE, C10100 H02)

Graphite blocks (2020 PT) + Titanium coating

(Not yet considered in analysis)

Aluminum blocks(EN AW 6082 T6)

Copper blocks (OFE, C10100 H02)

Tungsten blocks(Densimet 180)

Beam direction

Aperture for the beamCopper core(Jackets+blocks)

Shielding

Section A-A

Section B-B

Core’s cooling water pipes

Shielding’s cooling water pipes

B

B

A

A

Follow Up Meeting - TIDVG 3 – Thermo-mechanical study for future beams

4

Reminders

The aluminum blocks are the components that define the operational limits of the TIDVG.

Thermal study on the copper jacket and the blocks Mechanical study focus on the aluminum blocks

First results show that we need to accept to be over the yield strength (we are over the yield strength limit from the first pulse)

27th August 2014


5

Material limits

27th August 2014

Aluminum (6082-T6) limits after 350 hours of bake-out, max T of 250°C

Two bilinear curves are used (elastic and plastic behaviors): One at room temperature (22°C)

Yield strength: 77MPa Tensile strength: 145MPa Tensile strain: 12%

One at our limit temperature (250°C) Yield strength: 61MPa Tensile strength: 75MPa Tensile strain: 19%

Nota:

-these curves are calculated from the behavior of the aluminum 6061-T6.

Some tests are on going to define more precisely the properties of “our” aluminum.

-250°C is the limit chosen to not continue to degrade “too much” the aluminum properties.


6

Material limits

27th August 2014

77MPa

61MPa


7

Heat Exchanges

The heat exchanges between the blocks and the copper jacket are dependent of: The surface of exchange, SE, between the blocks and the copper jacket (conductibility)

The value of the thermal contact conductance , TCC(resistance at the interfaces)

These two parameters are the “key” of the TIDVG issues Unfortunately, they are poorly mastered:

1. The theoretical model to define the thermal contact conductance (TCC): several models exist with huge difference in results.

That’s why we conducted some experimental tests to choose the best model. The Mikic model (for metallic contacts) and the Marotta model (for graphite contacts) are easier to use and more conservative.

2. Heat exchanges between blocks and copper jacket are dependent of the pressure applied on the blocks, and so dependent of the structural behavior of the TIDVG. But the structural behavior is also dependent of the thermal behavior and the thermal behavior dependent of the SE and TCC.

More, the temperature in blocks and the cooling time are strongly dependent of the area of contact between blocks and the copper jacket.

Theoretically to study the TIDVG a structural-thermal strong coupled model is needed.

Problem:

- The coupling time makes the model strongly non-linear and it won’t make possible to have all the requested results by September.

27th August 2014

SE

TCC

Thermal behavior

Structural behavior


8

Heat Exchanges

Some assumptions are taken to make the model solvable (avoid the strong coupling): Define TCC independent of the temperature (the TCC at room temperature is a conservative assumption) Define a pressure profile for each material to consider the effect of structural deformation on SE

3.The heat exchanges also dependent of the flatness of the two parts in contact. This parameter does not appear in our model.

We consider the flatness of the blocks and the copper jacket good enough to not influence the SE and the TCC: this a strong non conservative assumption, tests are on going to try to evaluate this parameter. Flatness: 0.1mm Roughness: 0.0016mm

27th August 2014

SE

TCC

Thermal behavior

Structural behavior 1

Structural behavior 2

RoughnessInfluence on TCC

FlatnessInfluence on SE


9

Pressure Profile

TCC is pressure dependent, so we determine the pressure profile between blocks and copper jacket.

Worst case: Upper part of copper jacket at 100°C Lower part of copper jacket at 50°C Block at 50°C

We calculate the pressure profile for each group of blocks with same material. From this pressure profile, we calculate the TCC and set it in Ansys model.

27th August 2014

Upper part

Lower part

Block


10

Pressure Profile

Graphite

27th August 2014

TCC max: 17 400W/(m².°C)


11

Pressure Profile

Aluminum

27th August 2014

TCC max: 8 930W/(m².°C)


12

Pressure Profile

Copper

27th August 2014

TCC max: 12 750W/(m².°C)


13

Pressure Profile

Tungsten

27th August 2014

TCC max: 3 760W/(m².°C)


14

Thermal study – Results of beam R2_1

Thermal results for R2_1 beams - LHC-2.6-3.46E13-25ns

27th August 2014

At 25th pulse we reach the T limit (250°C)

Tim

e t

o b

e b

ack

at

35

°C

Heating: 518.4s

Cooling: 1821.6s


15

Thermal study – Results of beam R2_1

Cooling time for 5 pulses

27th August 2014

Tim

e t

o b

e b

ack

at

35

°CHeating: 86.4s

Cooling: 1101.6s

Comparison between 5 pulses and 25pulsesNon-linear behavior:Ratio number of pulses: 25/5=5Ratio cooling time: 1821.6/1101.6=1.7


16

Structural study – Results of beam R2_1

Plastification in the most stressed volumes Plastification is not on the face of contact between blocks and copper jacket: no permanent deformation and

so no influence on the heat exchanges. At the subsequent 25-pulses cycle, the plastification zone should increase, and so on (calculations are on-

going to confirm this)

27th August 2014

1st pulse25th pulse


17


Strain values The strain are very far from the limit: 0.6%<<12%. No risk of breaking.

NOTA: in plasticity, we abandon looking at stresses and strains becomes the reference. We must be safe with respect to the Rupture strain (maximum elongation)

27th August 2014


18


Deformation (view scale: x1000) at the peak of 25th pulse The contact is loosen on the majority of the area: heat exchange is loosen, so the thermal behavior should be

worst than the one calculated.

27th August 2014

Bottom view

Side view


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Worst case – Results of beam R2_1

Worst case for beam R2_1 No conductance between the blocks and the copper jacket No conductance between blocks The heat exchange are only due to radiations

Number of pulse to reach 250°C: 18 pulses (25 pulses in the model with conductance) Time of cooling to be back at 35°C: calculations on going but for sure too long…

27th August 2014


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Conclusion

The confidence in the numerical model to predict the behavior of the TIDVG is low. With this model beam R2_1 is limited to 25 pulses + 30 minutes cooling time.

Solutions: Reduce again the heat exchange surface in the current model: how find the

minimum surface exchange to consider? More, the number of pulses will be reduced and the cooling time extended.

Try to build and solve a strong coupled model but without knowledge of the real flatness of each block and of the copper jacket, this model could be not so useful.

Survey the water temperature during operation to know the real power evacuate by the water: If the temperature of the water increase as predicted in the numerical model so we can consider that the

heat exchanges between the blocks and the copper are the ones predicted in the numerical model. If the temperature of the water increase faster, the heat exchange are better than the ones predicted. If the temperature of the water increase slower, the heat exchange are worst than the ones predicted. Too

much power is stored in blocks, so we are closer to the melting limit.

27th August 2014

TED BEAM PARAMETERS

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• TED 87765 in TI8. Worst case scenario in terms of β within the injection lines TI2 and TI8



RUN 2

Energy[eV]

I[p+/bunch]

N. Bunches[Bunches/shot]

Total p+[p+/shot]

Bunch Spacing

[s]N. Batches

Batch/bunch]Batches

Separation[s]

Pulse Duration

[s]

Pulse Period

[s]σx

[μm]σy

[μm]β

[m]

1 450E+9 1.20E+11 288 3.46E+1325.0E-

94 225.0E-9 7.2E-6 21.6

810.58571

387.9934

βx= 121.201

βy= 27.7692 450E+9 1.20E+11 144 1.73E+13

50.0E-9

4 250.0E-9 7.2E-6 43.2550.6845

5263.5896

1

3 450E+9 1.60E+11 144 2.30E+1325.0E-

94 250.0E-9 3.6E-6 43.2

870.708725

416.771767

22

Thank you for your attention



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FOLLOW UP MEETING - TIDVG 3 - Thermo-mechanical study for future beams

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