Ribs in Outer Environmental Shield.

1
Ribs in Outer Environmental Shield.
Alexandre Riabov (IHEP, Protvino) Justin
Greenhalgh (RAL) EE/362/AR/03
2
General Issues

• This work is based on the note Request for
  further thermal Analysis work on Outer
  Environmental Shield (EE/346/RJSG/2003) by
  Justin Greenhalgh.
• 3D Finite Element model of a 15-degree sector of
  the OES between normal cross-section and ribs
  cross-section has been used. Geometry was taken
  from Andrew Levins latest drawings.
• Air above the OES is at 3K film coefficient is
  5 or 2.5 W/m2K.
• The SS cooling pipes (id12/od14) are brazed
  (Kbr50 W/mK) or glued (some thermal conductive
  material with K1W/mK).
• The ribs are made from SS (Kribs20 W/mK) or
  Textolite (0.25).
• Five bolts are from SS (20 W/mK).
• All Aluminum parts have the thermal conductivity
  180 W/mK.

3
OES_R. Normal Cross-section
4
OES_R. Ribs Cross-Section
5
OES_R. Fragments
6
OES_R. Paths Definition
Path 2
Path 1
7
OES_R. Summary Results.
Path 1 the path across the lower surface of the
Inner Skin at the Normal Cross-section. Path 2
the path across the lower surface of the Inner
Skin at the Ribs Cross-section.
8
OES_R_1. Overall Temperature
9
OES_R_1. Temp in Inner Skin
10
OES_R_3A. Overall Temperature
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OES_R_3A. TEMP in Inner Skin
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OES_R_1. Temp along the paths
Path 2
Path 1
13
OES_R_1A. Temp along the paths
Path 1
Path 2
14
OES_R_2. Temp along the paths
Path 1
Path 2
15
OES_R_2A. Temp along the paths
Path 1
Path 2
16
OES_R_3. Temp along the paths
Path 1
Path 2
17
OES_R_3A. Temp along the paths
Path 1
Path 2
18
Conclusions - 1

• The results from this detailed model are
  compatible with the results of earlier work in
  EDR-06 and EE/289.
• The effect of the ribs is alter the form of the
  temperature distribution along the inner surface
  of the skins, on path 2. However, the maximum
  an minimum values are not greatly affected
  regardless of the material of the ribs. Compare,
  for example, path 1 with path 2 in R_1 or R_2.
• The effect of the brazed vs glued connection is
  more significant. Compare, for example, R_1 with
  R_2.
• The effect of the film coefficient is also more
  significant than the presence or absence of the
  ribs.

19
Conclusions - 2

• With the most pessimistic assumption about the
  rib material, the film coefficient and the pipe
  joining material, the maximum temperature seen is
  0.21K.
• This will not have an unacceptable impact on the
  EE performance because
• The crystals will be influenced more by the
  backplate to which they are conductively coupled
  than by the OES.
• Only a few crystals around the periphery of EE
  are affected.