Transcript Section 4.6 - X-LAT Thermal Design

GLAST LAT Project
Gamma-ray Large
Area Space
Telescope
March 27, 2003
GLAST Large Area Telescope:
Mechanical Systems Peer Review
March 27, 2003
Section 4.6 - XLAT Thermal Design
Boris Yendler
Lockheed Martin
Thermal Engineer
[email protected]
Section 4.6 Mechanical Systems XLAT Assy
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Topics
•
•
•
•
•
Requirements
Thermal Design Overview
Thermal Model
Results
Summary & Future Work
Section 4.6 Mechanical Systems XLAT Assy
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Driving X-LAT Thermal Requirements
Parameter
Requirement
Design
Margin Comply
Operational Temperature Limits (6 HPs) -20 C to +35 C -4 C to +24.2 C +16/+11
°C
Operational Temperature Limits (1 hp
-20 C to +45 C
TBD
TBD
failed)
Survival Temperature Limits
-40 C to +40 C
TBD
TBD
Heat Distribution from Electronics
See Agreement
N/A
N/A
Y
Y
Ver.
Method
A, T
A, T
TBD
Y
A, T
N/A
Verification Methods A: Analysis, T: Test
Based on: X-LAT Plate Performance Specification, LAT-TD-01240-D2, Draft, Dated 6 Mar 2003
X-LAT Plate Assy Source Control Drawing, LAT-DS-01247, Draft, Dated 7 Mar 2003
Mid-Plate Assy Source Control Drawing, LAT-DS-01257, Draft, Dated 7 Mar 2003
Agreement Reached at Electronic Box Thermal Design Red Team Mtg, 14 Mar 2003
Section 4.6 Mechanical Systems XLAT Assy
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Thermal Design Overview
Thermal Design Goals
• Remove Heat from Stacks
• Reduce temperature
gradient on X-LAT
• Provide temperature at the
box baseplates 40 C
EPU
All TEM/TPS Positions
w/o an Electronic
Module have EMPTY
Boxes mounted to them.
PDU
EPU
GASU
EPU
SIU 1
SIU 2
+Y
+X
+Z
Four central TEM/TPS
Positions have Comb
Bracket mounted to
them.
Section 4.6 Mechanical Systems XLAT Assy
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Comb Bracket
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X-LAT plate Thermal Model
Foot Print of Stacks
Z
Y
X
heat pipe
Comb Bracket
EPU
PDU
Empty
EPU
heat pipe
Empty
GASU
Empty
middle plate
Empty
heat pipe
EPU
SIU
SIU
Empty
heat pipe
heat pipe
Hot Case
heat coming from GASU stack
heat coming from PDU stack
heat coming from SIU stack
heat coming from EPU stack
heat coming from EMPty stack
82.4
46.9
41.6
38.7
14.4
Section 4.6 Mechanical Systems XLAT Assy
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XLAT Thermal Model (cont)
 X-LAT plate consists of 3 plates AL 6061 T6
 Plates are jointed by #6-32 bolts 1 in apart

Side plates – 3.175 mm (1/8 in.) Middle plate -4.76 mm (3/16 in)
 CCHP flange is connected to X-LAT plate via RTV and rivets
 All stacks are thermally connected to X-LAT plate through 4 cm
wide strips of Veltherm, fiber based material (150 W/m2-K)
 10 stacks consist of 3 boxes: TEM, TPS assembly and EPU, SIU,
or EMPTY box
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Electronics Box Thermal Model

1 stack - 2 TEM/TPS assemblies connected to PDU

1 stack - 4 central TEM/TPS assemblies connected to GASU
and to Comb Brackets

Flange determines contact area between boxes in a stack.

A box in a stack consists of four walls, top and bottom. Heat is
generated on wall and /or top/bottom

Each side of the box is represented by one node

X-LAT plate is represented by 1763 nodes
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Thermal Results (X-LAT plate)
Y
17.3
X
EPU
20.3
22.6
17.3
17.3
24.2
PDU
EPU
20.4
20.3
GASU
22.3
21.3
19.4
EPU
SIU
SIU
20.1
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Thermal Results (box level)
TEM
33.8 C
TPS
EPU
TEM
35.6 C
TPS
33.7 C
33.5 C
SIU
23.4 C
TEM
TPS
26.5 C
28.3 C
27.4 C
Empty
23.9 C
Heat pipe temperature is assumed 17 C
Section 4.6 Mechanical Systems XLAT Assy
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Electronics Box Thermal Results (cont)
TEM
35.2 C
TPS
32.0 C
PDU
24.4 C
35.4 C
TEM
TPS
32.8 C
GASU
26.8 C
GASU
30.0 C
Comb
Heat pipe temperature is assumed 17 C
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Summary & Future Work
• Summary
– X-LAT Assembly Temperature Gradient is 5 C
– Maximum Electronics Box Baseplate Temperature
is 35.6 C
• Future Work
– Update X-LAT Model
• Refine Nodalization
• Optimize Localized Plate Thickness
• Incorporate SLAC Electronics Box Model
– Heat Pipe Failure Analysis
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