TFAWS 2011 – August 15-19, 2011 1
EIFIFI'CIENT THERMALLY COINDUCTIIVE STRAP DESIGN FOR CRYOGENIC PROPELLANT TANK SUPPOIRTS AIND PLUMBING
AlBSllRACT
J.P. E ¢ er . R. C h ri "c~e A A Glenn Ik carch Center
p, Gebb}' Vant;;tgc; y "tclmi. i nc,
A •. Ka ihanm :\tJ.a Sc "e: l" fie
.Opal,ltd .. Lewi Educational Illld It search Collaoorative IfltenlJtip' Program
After evalu1ating NASA space architecture goals. the Office of Chief Tel;;hnologis,t identified the need fur developirl!! enabling technology for long t erm lo iter~ in ~pace wit h cryogenic flu id~, One such t ed mology is stJrUctural heat interc@lPt ion. In this prototype, heat interception at the tan k support stmt Wllt!> accomplished usil1ga tilellTlalty conduct iv@ link to tih@ broad area oCOol@d shi@ld. Th@ d@sign methodology for both locating he h@at int@ r,c@pt and pr·edictlng the reductiQn in boll-off he<JIt leak is discussed in detaiL IResu lts from the chosen desilgn are prese,ntedi. It
W<I.s found that cOl'ltact resistance resu lt ing from different meohal"1lca l i3Jttacl'lment techn iques played a slCl'lmcant role in the form and functionality of a successful design.
https://ntrs.nasa.gov/search.jsp?R=20130000437 2020-03-24T03:11:32+00:00Z
Presented By
J.P. Elchert
Efficient thermally conductive strap
design for cryogenic propellant
supports and plumbing J.P. Elchert (NASA GRC), Craig Opalach (OSU), Robert
Christie (NASA GRC), Paul Gebby (Vantage at GRC), and Ali
Kashani (ASRC at ARC)
Thermal & Fluids Analysis Workshop
TFAWS 2012
August 13-17, 2012
Jet Propulsion Laboratory
Pasadena, CA
TFAWS ActiveThermal Paper Session
Cryogenic boil off reduction system test
TFAWS 2011 – August 15-19, 2011 3
Utilizing a reverse turbo Brayton cycle cryocooler (Creare, Inc.)
TFAWS 2011 – August 15-19, 2011 4
Vacuum apparatus and radiator
TFAWS 2011 – August 15-19, 2011 5
Broad area cooled shield
TFAWS 2011 – August 15-19, 2011 6
Piggybacking off the cooled shield
TFAWS 2011 – August 15-19, 2011 7
... 1......-------Teak!
t--I ------------;:?> X
IIII ----.-----, I Tsur I
I
.. Thot
Ideal temperature profiles
TFAWS 2011 – August 15-19, 2011 8
,
, /
,
" " .'
...
.' .' . -.-" _-----" ~
." '" . / :'/
o
,,-
Oi crete cooling
.. '
.---
, . . " ....
..--
:
:
--
I
:
--
Distance along .trut starting from "old md
Initial conceptual sketch
TFAWS 2011 – August 15-19, 2011 9
i ndi urn foi I under copper Ii Ilk
titani urn stwt "flexible G{) ICIQuctive li nk {FCL)", 3 hi9hpurity copper layers, 1mm x 20mrn x 7 in
to B C
Four steps
1. Sizing with `ideal’ model
2. Detailed design
3. Validate with most detailed model
4. Troubleshoot and redesign
TFAWS 2011 – August 15-19, 2011 10
Step 1: Sizing the thermal link
TFAWS 2011 – August 15-19, 2011 11
09,
O~
01
O~
0' i 1
II"" 0.-(" ...... \1
0"'
O~
I / ~(::..r--
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01 I ~II;; ~-~-- ~ -~ ~ ~ L.E.:t1=~_-_.o-. - y :.=:0: ~=O::t. r U=: U-~ - 1 - rV -..",,- ~ ...
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- "AI - tit. ..... ~ -Ill ' OD:! 'lift
~H!t. ..,. trn:.p' ...... 10> • 0.01 WI
- . - "'.1<.11> <:Oo'4I ...... !Ii . 0 I _ .... -.- "'01; ___ ~Iii
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ItPt htl'rc,pe nodt 1110 . I) ~ WJ1;1
ok '" ."ld .,.do jr,; • ... lOy I.. n: .... o"" I~ ' j 'iY
l
Semi-flexible ETP copper bus bar for prototype
TFAWS 2011 – August 15-19, 2011 12
Storm copper components, Co.
http://store.electrical-insulators-and-copper-ground-bars.com/flexible-insulated-busbar.html
Flexible Insulated Busbar
Step 2: Detailed sizing via trial and error
TFAWS 2011 – August 15-19, 2011 13
• one dimensional, steady
state, constant properties,
no heat generation model
• utilizing a few flexible
thermal link specific
parameters and estimates
(shape efficiency, for
example)
• More information on this
approach can be found in
the Spacecraft Control
Thermal Handbook,
Volume 1.
First iteration hardware
TFAWS 2011 – August 15-19, 2011 14
1 inch H
First iteration hardware
TFAWS 2011 – August 15-19, 2011 15
1. Thermallink
2. Indium Foil
3. Original Collars
4. Titanium Strut
Prototype pictures
TFAWS 2011 – August 15-19, 2011 16
Prototype pictures
TFAWS 2011 – August 15-19, 2011 17
-
Step 3) Validation
TFAWS 2011 – August 15-19, 2011 18
Node >JOO
300
281. 7
263 3
245
226. 7
20B. 3
190
17J.7
153. 3.
1J5
116.7
98. 33
80
6J. 67
AT 33
25
<25
T e~De,oture CK), 1;~e o SE'C
Step 3) Validation
TFAWS 2011 – August 15-19, 2011 19
/C.C -J
225
2 11 3
197. 7
184
170. 4
156. 7
143.
129. 4
1 15. a
102.
88. 49
74. 84
6 1 18
47. 53
33. 88
20. 23
Step 3) Validation
TFAWS 2011 – August 15-19, 2011 20
Ti 6AI 4V, t = 0.0236 in, actual geometry of strut Tc = 20.23K, Th = 22SK, Tbac = 78.9 K, Trad = 220K
FCL: Storm's Maxiflex Cu Bus (20mm X lmm X 3 layers) Attached by "wrapping" (see schematic)
0.075
0.06
Heat Flow into 0.045 Tank
[Watts/strut] 0.03
0.015
o
JP Elchert 5/4/"lon
\ ... ~ .... e- rr- -....
'" - , .... ,.. -- - - ', ' - / ~
,. H. ~ "'""-.~ - , ",
v..; .,;?-b .:; "/ .....
2 3 4 5 6 7 8 9 10 11
FCL's attachment location on the strut [inches]
2 1.8 1.6 1.4 1.2 Heat Flow into 1 BAC 0.8 [Watts/FCL] 0 .6 0.4
0.2 o
- - TANK; h = 100 W/m2-K; AI Tape Covered FCL middle segment
- - TANK; h = 1000 W/m2-K; AI Tape Covered FCL middle segment
- - TANK; h = 10 W/m2-K; AI Tape Covered FCL middle segment
- - TANK, Total Conductance = 0,02 W/K
- - Tank; Total Conductance = 0,013 W/K
- FCL; h = 100 W/m2-K; AI Tape Covered FCL middle segment
- FCL; h = 1000 W/m2-K; AI Tape Covered FCL middle segment
- FCL; h = 10 W/m2-K; AI Tape Covered FCL middle segment
- FCL, Total Conductance = 0.02 W/K
-FCL, Total Conductance = 0.013 W/K
21
Contact resistance concerns (Gebby results)
22
Model prior to loading (credit Gebby)
Nominal dimensions used.
Expansion Coefficients:
•2024 Al Plate = 1.255E-5
•Ti-6Al-4V = 4.8E-6
0.016 gap in G13709MRA049
reduced to 0.007,due to assembly at nominal part sizes.
23
Deformed displacement, neglecting CTE
z ......
Oulpul Sel NO THERMAL EFFECTS Deformed(O.0781): Total Translation
24
Contact Pressure (psi)
Average contact pressure = 81 psi
Standard deviation = 113 psi
25
Deformed total displacement, cooled to 100K
Initial 0.007” assembled gap reduced to
no gap on one side due to thermal contraction of parts.
26
Contact pressure (psi), cooled to 100K
Average contact pressure = 927 psi
Standard deviation = 1535 psi
This doesn’t seem correct,
due to sleeve binding; would result in
plastic deformation
Step 4) Redesign
TFAWS 2011 – August 15-19, 2011 27
Total conductance ~0.05 W/K
TFAWS 2011 – August 15-19, 2011 28
Thermal Desktop Model: Summary of Results (Kashani results)
Page 29
Heat Leak to Tank (W) Heat Removed by ATC System (W)
MLI Struts Stand-
offs Vent Total MLI Struts
Manifol
d Total
1.1590 0.6315 N/A 0.5441 2.3346 N/A N/A N/A N/A
1.1491 0.6052 0.1818 0.6654 2.6015 N/A N/A N/A N/A
0.2483 0.1347 0.0607 0.2237 0.6674 6.0659 1.8704 1.6293 9.5656
0.2477 0.1991 0.0606 0.3178 0.8252 6.0692 1.6446 1.239 8.9528
0.2480 0.1638 0.0606 0.2234 0.6958 6.0676 1.7702 1.6326 9.4704
T
shroud
(K)
T sup
ring
(K)
Sup
ring
Heat
(W)
T reject
(K)
Strap
cnd
(W/K)
Mass
flow
(g/s)
T
shield/
cooler(
K)
Q
cooler
(W)
P input
(W)
220 249 28.52 N/A N/A N/A N/A N/A N/A
220 249 28.52 220 0.013 N/A 199 N/A N/A
220 250 28.52 275 1 2.0 77.2 11 277
220 248 28.52 275 0.013 2.0 77.2 11 277
220 248 28.52 275 0.03 2.0 77.2 11 277
Reduction in heat leak
• Reduction in strut heat leak of roughly 70%
• Temperature gradient across thermal link of roughly 10K;
temperature gradient drives the design less than
conductance
• Fin efficiency still above 90%
• Using bus bar for the prototype was economical; a true
flexible foil copper thermal link with state of the art end
pieces would perform better (eliminates some contact
resistances)
TFAWS 2011 – August 15-19, 2011 30
Extra: Intro. to general strut heat transfer
• Boundary conditions
• Conduction
• Radiation
• Insulation
TFAWS 2011 – August 15-19, 2011 31
Textbook conduction
TFAWS 2011 – August 15-19, 2011 32
&
Fox and Scurlock’s Boil off experiment
TFAWS 2011 – August 15-19, 2011 33
t
"',.."o,tm •• of I'It,L~m (iln.- (lid]
"gut'. " ~ nm. - -; . .• "dl.. • . .PM' I . t .... 1M dOtlll lUb.aO
A gradient exists through the attachment brackets
TFAWS 2011 – August 15-19, 2011 34
TFAWS 2012 – August 13-17, 2012 35
`Optimum’ uniform emissivity
Heat leak as a funct~ion of emissivity
1.22
- -- - -
1.2 j
!-C-. t '" t ~
t I
~ • - • t ~
• . -
t •
• ... t t ~ + +
1.12 • t ~
1.1
- t • • • • .. • _ . ~ t-- l- t
o 0_25 0_5 OJ5 1
Em is SiViity
Emissivity of inner coating of tube
TFAWS 2011 – August 15-19, 2011 36
Boyle, Robert J. and Richard H. Knoll, “Thermal analysis of shadow shields and structural members in a vacuum.” D-4876, NASA Lewis Research Center, 1968
~ ...!l ·0 !. ~
i ~ .. ~
:; -
Figur
.1 --- CIo< .. Indi ---Open ends
. 6
til.,. ...
•• • "lnlwlty .
. l .. 0
.2
.6
.9
.~
.Ol
. 01
. DI~~---'---'-~-::' o .2 .' .• .8 lO
laJ Rollo 01 ,trill i«l9I" 10 dl.met«, 5r;: radiatian to eoMUtllon !W . ....... 125.
.2
[.dernll ... 1"lvIly. ..
0
.)
.6
••
.2 .4 .6 .8 LO Inlem.t rmiuirity. c.,
llil Rollo 01 strut lenqth to dim"". ~ nodiollon IOtonduCl lon PlrH'lettt. 500.
.01
.OJ
.01
Ut.rnll .MISslvly. '. 0
. l
. 2 .4 .6 .1 1.0
'e) Rollo 01 ",ut Itnglh I. Oi~tr. 2t\ rldlltlon loc;ol'ufucl ion lWlmftfr.
In their analysis, t he external, large, isothermal urrou nd ings tempera tLU'e was Laken to b OK.
Extending Boyle and Knoll’s work
TFAWS 2011 – August 15-19, 2011 37
Noele >300
300
272
244
2 16
lee
160
132
104
76
48
X
20
<20
T e!"!DE'roture [KJ , T i Me =- 0 sec
Extending Boyle and Knoll’s work
TFAWS 2011 – August 15-19, 2011 38
Comparison of hypothetical configurations as a function of internal
emissivity 0.932
0 .93
0.928
i O.926 ...... ..¥ 0.924 IV ~ .... 0.922 ... IV • ~ :J: 0.92
0.918
0.916
0.914 o
StBlnlesssteeltube , 12 Inches In le ngth, l lnch ., d&ameter. 0.06 Inch w all thickness
• • •
Hot boundary node al300K COld boundary nod@at 20K Surroundings temperature of 200
" t + • • •• • • " • • • , • • • • • • • • • • • •
• • • )< •
• • , • •
• • • • • •
• .
• " " • Ii • ...
0.25
... ...... ...
0.5
Internal Emissivity
• • • • • • • • • • • •
" " • •
...
0.75
• • • • • • " " • •
...
1
Critical length / fin problem
TFAWS 2011 – August 15-19, 2011 39
350
300
........ 250 ::.:: ...... Q,I
~ 200 1V .. Q,I 150 c.. E ~ 100
SO
0 a
In a radiation dominated environment, increasing the length beyond a point yeilds
no additional reduction in heat flow
20 40 60 80 100 120
Distance 8,Iong length of pipe lin)
• T(x, L = 100")
• T(x, L = 40")
*No M LI
Disclaimer
• All copyrighted works were adapted partially—never in whole—for fair use and informational
purposes only. All pictures belong to the original owners and were shown in a private setting
meant to spur thought, learning, and discussion. We do not use those works for commercial
purposes nor do we claim credit for anything not expressly declared to have been created by the
fine folks at the NASA Glenn Research Center. Anyone interested in more information about
those resources will be able to find the original copyrighted works in the bibliography shown
below.
• All trademarks are the owner’s alone and references to companies should be considered neither
endorsements nor rejections of said company.
• All opinions are those of the presenter and not necessarily those of NASA
TFAWS 2011 – August 15-19, 2011 40
Bibliography
• Electrical Bus Bar. Storm copper components, Co. http://store.electrical-insulators-and-copper-ground-
bars.com/flexible-insulated-busbar.html
TFAWS 2011 – August 15-19, 2011 41
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[2] 1-'aulo 1\ . August.o, 'I'crcS/t CftS~cJo-Cmlldc , Pedro Augusto, fJ.lld Uomingos Barhosa-. Op;imization of refrigerated shield3 Ilsing Illultilayer thel lIlal insulation: Cryostats design - analytical solution. Cf'!Ioqenics, Jun 20C!G.
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[5] !\drian Hcjan Illld !:::yJvic Lorcntc . lhc constructai Jaw of dcsign finci c\·olution in nature, Phl/080phica! TmnSocilOnt of Th e Royal Society, pages 1335- 1347,2010.
[G] R.ohert .I . Boyle and Richard H. Knoll T hermal analysis of shadow ~h i , 'ld- Hlld SI,flld l ll'H.i II I P lllh!~I'" i l l >1 VH,'IIII II I Tp. :hllil :al \'ol!~ n-437G, NAS.l, I , !~wi~ Rp_~>lI'l ll C~III.!~f '1m 1963
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[Il] E, R, Ca ll<l.VU n ami f , K. Millel , Opnmizoo he<l.t ill\crceptioll for CI)'ogm tank suppml. III Ari"c)lc~;I III CI'j,'oytm,; £u:J1!l~el'mg, 'mlllm€ fj3A ~lId :;38. 2007.
[f!] .I ,C. Chaw and .1 . .'.1. Khodadidi. Optimizat ion of cooled ~hields in illsula tion;; . ASME 1ffil'...;actjo 'l ~, jo',rIl<l1 oj Ilea~ T ((Hls/er, 106 (,1):871- 875. 19&.1.
[HI] ClI liimor€ ami R.ing , editor~, Sillcps 1.';l IT'S .UC) I~'uJ , Cullimore ami Ring T~c1ll101o3ies , Inc .. 20ll
[ll] A.G. Fox and R,G. Scurlc<:k A le:;ter to the editor. Cl"!1' OlI~'lic~, F"b 1%7. Department of Physics. Cniversity of Soulhamptoll, UJ(
[12] M.A , lIilal <Lnd rt.\V. ]}oom , Optimimlion of mechanical ;;!l JlPort s for large superconductive magnets. In rrrx;eee;r:9S, lntem~ti()t!al Cr:.'O!!~tlI C
Mal ITia,s CO'lfef't ll(e in Kingston, Or:icrio, Ca nada, 1975, I'olume AIT-42172 L9-31 , 1977
[13] M.A , llila l al:d y.1>1. Eyss;". ;'linimiza1: ioll of rdrigeration power for large cryogenic sy!;tems, Ad"{l nc~.~ in Cr~OlIt~!iC EIl9i1we:"1tl9, 2&. 1980.
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Tm.'1$J~:". Wiley, 6 edition , 2007
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[Ii] National in£liulle of S, andards ana Technology \NIST ;' 11a-terial properne~. http,l/crp3enics .nist .go'l/MPropsHAYj material properties . h":m, 2012. Cryogenic Technologies Grol\p
[18] A. R. Shouman. Nonlinear heat transfer [lnd tem perature distribution through fins and electric filaments of arbitrary geolIletry with t.elltperlJ.t,ure-oep1:!uucut IJIUI.HOrlies auo heat t\ell+~ntLiull . Tcdlltical report, NASA , Jan 19G8.
[191 Chi K. Tsao. Temperature distribution and power loos of a gas-cooled support fo r a c ryogcnic conta incr , Cryogemo , 197·1.