end-cap mechanics fdr cooling structures

CLRC 1S Temple

End-cap Mechanics FDRCooling Structures

Steve Temple, RAL

1 November 2001

CLRC 2S Temple

End-Cap Disc ServicesCooling Structures

Full details - See ATL-IS-ER-0021 Cooling Circuit Layout

» 3 circuits per quadrant - corresponding to inner, middle and outer module rings

» 3 separate Inlets, 3 outlets are manifolded at patch panel

» Outer and middle module Circuits - Two point cooling

» Inner module circuit - Single point cooling

» Bend radii (inner) kept to 5 times OD i.e. 18.7 mm

Cooling Component Materials/Joining Techniques» C-C cooling blocks

» CuNi pipe - 3.6mm ID, 70 µm Wall

» Cu plating (sputter coat + electroplate) of cooling blocks enables soft soldering to cooling pipe

CLRC 3S Temple

Mechanical Requirements» Position modules to a positional tolerance of 134 microns

(diameter) in the R-phi direction, for one module relative to its neighbour

» Provide co-planar mounting surfaces for modules» Minimise forces transferred to the support structure i.e. carbon

fibre disc» Operational for 10 years» Lowest possible mass

Thermal Requirements» To ensure the highest temperature of any part of the silicon on

a module doesn’t exceed -7 °C


CLRC 4S Temple

Cooling Pipe Circuit Design» CuNi material chosen for its excellent resistance to corrosion, and its excellent

solderability

» ‘Wiggly’ pipe Layout reduces forces on disc from thermal contractions and pipe manufacturing tolerance

– Thermal Contraction Forces

Forces calculated using an FE model, using following material properties and boundary conditions :

E=152 GPa, = 12e-6/K, T=50K

– Pipe Manufacturing Tolerances

Deviation of pipe bend centres from nominal positions kept to a minimum, through tooling design

In addition stress relieving of manufactured circuits is proposed - testing is planned in next round of prototyping


CLRC 5S Temple

ANSYS 5.5.3SEP 23 200114:37:31PLOT NO. 1DISPLACEMENTSTEP=1SUB =1TIME=1PowerGraphicsEFACET=1AVRES=MatDMX =.101142

1

NFOR

DSCA=105.01ZV =1DIST=114.691XF =-157.26YF =294.168ZF =-7.5Z-BUFFER

pipes_inner.asm

1.10 N

0.42 N

0.34 N

0.03 N

0.11 N

0.06 N

0.16N0.08 N

1.42 N

0.38 N

33.3 Nmm

8.7 Nmm

19.3 Nmm

18.4 Nmm21.2 Nmm

Inner Circuit


CLRC 6S Temple


1

NFOR

*DSCA=100ZV =1*DIST=128.989*XF =103.967*YF =-471.282*ZF =.127957Z-BUFFER

td-1002-337.igs

15.8 Nmm

1.98 N

0.06 N

0.07 N

0.05 N

0.02 N

0.08 N

0.40 N

0.03 Nmm

2.60 N1.43 N

11.71 N

0.8 N

0.03 N

12.04 N

17.5 Nmm

17.5 Nmm

9.4 Nmm

74.3 Nmm 6.4 Nmm

22.4 Nmm

Outer Circuit


CLRC 7S Temple


1

NFOR

*DSCA=100ZV =1*DIST=164.153*XF =-375.285*YF =162.547*ZF =5.479Z-BUFFER

pipes_middle_asm.igs

0.16 N

10.8 Nmm

2.53 N8.1 Nmm

0.08 N

0.17 N

0.12 N

0.07 N

0.39 N

0.03 N

4.35 N

1.84 N

27.16 N

0.16 N

27.08 N

23.8 Nmm

22.6 Nmm

108 Nmm

13.5 Nmm

43.6 Nmm

0.01 N

Middle Circuit


CLRC 8S Temple

Cooling Pipe Prototyping» First prototype - Inner cooling

circuit for system test» Old circuit design - Internal

bend radii of 14mm» Ice used as filler material» Custom made pipe bender

designed and manufactured» Manufactured at RAL


CLRC 9S Temple

Cooling Pipe Prototyping (Cont’d)» Second prototype - Single U

shaped bend» Internal bend radii of 20mm - 5

x OD» Cerobend used as filler material» Swaged ends - enables low

mass joining of pipes» Manufactured by established

pipe bending company


CLRC 10S Temple

Cooling Block Design» Primary Cooling Block

Thermal Design– C-C material chosen for good thermal conductivity - 300 W/m2K

(fibre direction), 50 W/m2K (transverse direction)– Fibre orientation optimised– Straight split corresponding to hybrid and silicon – Further details see thermal performance

Mechanical Design– Machined module location boss– Planar module mounting surface wrt block mounting surface– Accurate cooling block height


CLRC 11S Temple

Cooling Block Design (Cont’d)» Second Point Cooling Blocks

Thermal Design– C-C material chosen for good thermal conductivity - 300 W/m2K (fibre

direction), 50 W/m2K (transverse direction)– Fibre orientation optimised

Mechanical Design– As primary cooling block

» Second Point Mounting Blocks

Thermal Design– No thermal requirements - Made from low mass PEI polymer

Mechanical Design– As primary cooling block

End-Cap Cooling StructuresCooling Block Design

CLRC 12S Temple

Cooling Block Prototyping» Two prototyping exercises

(old and current design)» Several manufactured,

metrology checked to assess ability to machine key features within appropriate tolerances

– 3mm OD location boss– Parallelness between

bottom and top surfaces– Block height dimension

End-Cap Cooling Structures

Cooling Block Design

CLRC 13S Temple


Cooling Block Prototyping (Cont’d)» Current cooling block design metrology results

» Improvements to design for machining operations

simplification identified

CLRC 14S Temple

Joining of C-C Blocks to Cooling Pipe» Soldering of cooling blocks to pipe

– Good thermal joint– Good mechanical joint - Soldered joint sample (using swaged end)

undergone helium vacuum leak test – Standard SnPb (60/40) solder with non-corrosive Castolin 197 flux.– Requires Cu plating of C-C block

» Cu Plating of C-C Blocks– Plating trials show good adhesion to C-C base material achieved

by :

Cleaning, Cu Sputtering, Cu Electroplating and Au Flash (to prevent copper oxidisation)

– 15 micron Cu plating followed by 2 micron Au flash


CLRC 15S Temple

Cooling Structure Precision Assembly» To achieve positional

tolerances required a precision assembly technique is performed during the disc services to disc assembly stage

» This involves a precision rotary stage (r-phi) and an alignment arm (providing radial position)

» Details see ATL-IS-ER-0022


CLRC 16S Temple

Cooling Structure Precision Assembly (Cont’d)» Blocks are required to be positioned in r-phi with a positional

tolerance of 66 microns - Out of 134 micron error budget» Results show this is readily achievable using this method


CLRC 17S Temple

Thermal Performance» Extensive prototype testing and thermal simulation carried

out on the Baseline Design (see ATL-IS-ER-0009) – Full cooling quadrant (3 circuits) manufactured and tested

on evaporative cooling rig

– Dummy thermal module mounted on sector and tested

– Successfully demonstrated a coolant temperature of -20 to -22 °C was sufficient to keep the inner module below -7 °C.

– Design consisted of Aluminium Alloy cooling blocks joined to Aluminium cooling pipes.

– Effect of material changes therefore need to be assessed


CLRC 18S Temple

Thermal Performance (Cont’d)» Assessment of cooling block

material change– C-C block substituted into

the simulation. Again boundary conditions - 4000 W/m2K @ -20C (7.5 W, 1W)

– Minimal change on silicon side. Better performance on hybrid side.

ANSYS 5.5.3SEP 18 200110:28:30PLOT NO. 1NODAL SOLUTIONSTEP=1SUB =1TIME=1TEMP (AVG)RSYS=0PowerGraphicsEFACET=1AVRES=MatSMN =-19.998SMX =-8.456

1

MN

MXX

Y

Z -19.998-18.716-17.433-16.151-14.868-13.586-12.303-11.021-9.738-8.456

CC Cooling Block - Temperature Plot - 4000W/m2K @ -20C

Al Tsil=-11.5°CC-C Tsil=-11.3°C

Al THyb=-6.9°CC-C THyb=-8.4°C


CLRC 19S Temple

Thermal Performance (Cont’d)» Assessment of cooling pipe material change

– Reduction in thermal conductivity and wall thickness results in reduction of convective heat transfer area.

– However as htc increases with heat flux, this effect will be decreased.

– Small scale prototype testing on an evaporative C3F8 cooling rig is planned


end-cap mechanics fdr cooling structures

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