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--

~

01 I ~II;; ~-~-- ~ -~ ~ ~ L.E.:t1=~_-_.o-. - y :.=:0: ~=O::t. r U=: U-~ - 1 - rV -..",,- ~ ...

0 I 1l\I1~ 5Mc .(I, IXlIiI

l rI

/ Ii /

V

.'j.~

7.:tf .-:~ - -- - -:tJ·~" I-- -"II

-.- KlrJli .. \.0 o;.Id ""'" jr,; • Q _ .. ---..... bt ln~rtl'pI'; nod.; Ie. DtDlw

- "AI - tit. ..... ~ -Ill ' OD:! 'lift

~H!t. ..,. trn:.p' ...... 10> • 0.01 WI

- . - "'.1<.11> <:Oo'4I ...... !Ii . 0 I _ .... -.- "'01; ___ ~Iii

"'lM sid' ..

1 (3O IKI

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

References

[1] ~'iark A. AbramSQIl. Mixed l'ariable (Jptimiz!l.tion of H load-bearing thel ­lIlal insulation system using a fi lter I)''l.ttern search algorithm. Optim. Enq. , 5 (2):157- 177, 2002

[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.

[3] Adriall R~ja ll h{llII'oJ/l"illh~I'mtll f! f'.< ![l1I. of d,~ O·!JrJ!Jf::,ii: mol-iliU s'!J~it':ln

for (l sllperconduciing £vnchruno11s genera/Of. PhD thesis, .lI.Iassachusctts Institute of Technology, Dec. 1974., handwriteen edit 'Le. Feb. 1975'

[4] Adrian BcjHn and J ,L. Smidt Jr. T hermodynamic optimisation of me­chflIlicai supports for cryogenic appamlns. C1'1Jogenic3, pag~ 158- 163 , 197·1.

[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

[7] D~"id Buslmdl. Optill:UIll dffiign of dewar fUpport.s. l. Sp()t:£CHljl. 22(.fH32- j.1l, WE5.

[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.

[14] Dergman La\'in~ Innopera, DeWitt. l'und;;menta,s of lIoot and MlIs~

Tm.'1$J~:". Wiley, 6 edition , 2007

[15] Latif l>.I. Jij i. Hwt Cm,dJJctioll. Springer-Verlag Berlin Heid.olberg, thi rd edition, 2009, Foundillg &Iitor L.L. Faulkn~r.

[16] Michael Kok:{olara;;, Charles Audel. and Jr. J .E. Dcnni.~ ~lixed variable opdmizatioll of the nnmber aJl(1 <composition of heal, illte rcept~ ill a thermal iusula, iOIl syatem Er!§in('H'l"9 and Optimizatio:1 2 (1 .1:5- 29, 2001

[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.