aerogel-based thermal insulation systems for ...

AEROGEL-BASED THERMAL INSULATION SYSTEMS FOR CRYOGENIC-VACUUM APPLICATIONS – PART 1 James E. Fesmire NASA Kennedy Space Center, Cryogenics Test Laboratory, KSC, FL 32899

Lighter than air?

AEROGEL MATERIALS LIGHTER THAN AIR?

CRYOTESTLAB

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AEROGEL BASICS World’s lightest solid material •

Lighter is not always better

World’s best insulation material •

CRYOTESTLAB

Yes (and no)

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AEROGELS FOR INSULATION 1.

Production & processing methods

2.

Types of aerogels/composites

3.

Properties & phenomena

4.

Thermal testing

5.

Thermal data

6.

Applications & problem-solving

Plus: Technical resources CRYOTESTLAB

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WHICH CAR IS THE BEST? INSULATION

•

It depends: function, price, performance, etc., etc.

PRODUCTION & PROCESSING METHODS •

State-of-the-art silica aerogels are derived from the supercritical drying of highly cross-linked inorganic or organic gels: • • •

•

Solution-Gelation (Sol-Gel) processing methods Supercritical drying step at the end Or, evaporatively dried for X-aerogels

Aerogels are once again an emerging material with the advent of sol-gel chemistry in the 1980s and use of advanced carbon-based processes in recent years

CRYOTESTLAB

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AEROGEL BLANKET COMPOSITE PROCESSING Sol-Gel Process (TEOS) 

Si(OEt)4 + nH2O + mEtOH

hydrolysis

catalyst Si(OH)4 + (m+n) EtOH



catalyst

SiO2 + 2H2O + (m+n) EtOH

condensation

Original “large-scale” autoclave system at Aspen Systems, Marlborough MA (1996)

RADIATION SHIELDING: Aerogels also produced in opacified [molecular sieve carbon (MSC)] fiber matrix for increased inhibition of radiation heat transfer in the infrared range CRYOTESTLAB

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TYPES OF AEROGELS/COMPOSITES •

Types of aerogels include: •

Silica

•

Organic •

•

http://www.aerogel.org/?cat=23

Resorcinol Formaldehyde (RF) and many others

•

Metal Oxide

•

Polymer Cross-Linked (X-aerogels)

•

Carbon (Carbon Nano-Tubes and Graphenes)

•

Semiconducting Metal Chalcogenide Aerogels

Forms: •

Monolithic (solids)

•

Particles (and packaged particles)

•

Flexible Composite Blanket

•

Aerogels can be tailored for a wide range of specific properties

•

Aerogels’ development has been highly dependent on the specific application CRYOTESTLAB

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Bulk-Fill Insulation Materials 10x

High Surface Area and Small Pore Size are the crucial distinguishing features of aerogels

100x

Glass Bubbles

*

~65m *zoom is 300x

Perlite Powder ~600m

Aerogel Beads

~2000 m

Ref: Fesmire, J.E., Sass, J.P., Nagy, Z.F., Sojourner, S.J., Morris, D.L., and Augustynowicz, S.D., “Cost-efficient storage of cryogens,” in Advances in Cryogenic Engineering, Vol. 53B, American Institute of Physics, New York, 2008, pp. 1383-1391. CRYOTESTLAB

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Flexible Aerogel Composite Blanket Materials

R&D 100 – 2003

Thermal Wrap Cabot Corp.

Cryogel, Pyrogel, Spaceloft Aspen Aerogels, Inc. and NASA Kennedy Space Center

(began 1993 under SBIR Program)

Ref: Coffman, B.E., Fesmire, J.E., Augustynowicz, S.D., Gould, G., White, S., “Aerogel blanket insulation materials for cryogenic applications,” Advances in Cryogenic Engineering, AIP Conference Proceedings, Vol. 1218, pp. 913-920 (2010). CRYOTESTLAB

Space Technology Hall of Fame – 2012 5/15/18

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X-Aerogel Materials AeroZero® Polymer Aerogels by Blueshift (part of FLEXcon) https://www.blueshiftmaterials.com/

 Tough, strong structural materials that are lightweight and low thermal conductivity

Blueshift AeroZero® Rolled Film polymer aerogel

 Commercially available polyimide cross-linked aerogels licensed from NASA in 2015  Years of R&D by NASA Glenn Research Center (Dr. Mary Ann Meador) and the National Polymer Innovation Center of the University of Akron Blueshift AeroZero® Stock Shapes CRYOTESTLAB

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Other Commercial Aerogel Materials Armacell  ArmaGel HT  High temperature insulation blanket (1200 F)

JIOS Aerogel  JIOS AeroVa® products  Production and manufacturing in Gyeonggi-do, South Korea

JIOS AeroVa® Aerogel Padding CRYOTESTLAB

JIOS AeroVa® Aerogel Tape

JIOS AeroVa® Aerogel Powder

AeroVa® Aerogel Coating 5/15/18

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AEROGEL HYBRID COMPOSITES

AeroFoam* is a new hybrid foam/aerogel composite

US Patents 7,977,411 and 7,781,492

AeroPlastic* is a new composite material of certain polymer and aerogel particle combinations US Patents 9,777,126 and 7,790,787

AeroFiber* is a new hybrid laminate

system composed of fiber composites and aerogel blankets US Patent Pending 14/192,784  All are tailorable and represent families of different approaches, designs, and combinations CRYOTESTLAB

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ORIGINAL MOTIVATION

Real-world problem-solving for Space Shuttle flights: deep

investigation of specific, hard problems leads to practical5/15/18 knowledge, understanding, and new technologies.

CRYOTESTLAB

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CRYOTESTLAB

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PROPERTIES & PHENOMENA •

Density, mean pore size, internal surface area (material) Densities from 32 to 160 kg/m3 • Pore sizes from 10 to 40 nm • Surface areas from 800 to 1000 m2/g •

•

Bulk density and interstitial space (insulation system)

•

Aerogels are high performance thermal insulators due to their extremely small pore sizes which greatly impede the thermal communication of gas molecules

•

Cryo-adsorption or physisorption (not “cryo-pumping”)

•

Super-hydrophobic CRYOTESTLAB

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FLIGHT VEHICLE APPLICATION: Liquid Oxygen Feedline Bellows •

Cryoadsorption experiments performed with LN2 (77 K)

•

Demonstration testing at CryoTestLab, MSFC, and MAF showed aerogel-based system prevents ice formation

LO2 Feedline

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CRYOTESTLAB

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FLIGHT VEHICLE APPLICATION: SHUTTLE ET LH2 INTERTANK FLANGE •

Cryoadsorption experiments performed with LHe (4 K)

•

Demonstration Testing at CryoTestLab •

16 tests completed using liquid helium Effect of Aerogel Insulation on Temperatures Throughout Intertank

Insulation keeps the warm side warm, and the cold side cold, Preventing liquefaction of purge gas

+16K

+21K

+9K +16K +19K -27K +10K

CRYOTESTLAB

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CRYO-ADSORPTION EXPERIMENTS AT < 20 K •

•

Space Shuttle External Tank, LH2 Intertank Flange Insulation Investigation •

Using LHe (4 K)

•

Ambient pressure environment

GN2

Baseline runs without insulation inside tube •

•

LHe

LN2 dripping from 6 minutes until end of test (0.42 ml/sec)

Cold finger insulated with aerogel beads: •

No LN2 formation during 4-hour run

•

Aerogel beads poured out free and friable CRYOTESTLAB

Without aerogel

With aerogel

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THERMAL TESTING •

Apparatus and methods

•

Material specimen preparation •

•

Nano-porous materials (not cellular; not open cell)

Realistic/relevant conditions • •

Temperature Difference (∆T) is the key (not Tmean) Boundary temperatures (a hot one and a cold one!)

•

Environments: ambient to high-vacuum

•

High performance (low heat conductivity)

•

Interdependencies: thermal, mechanical, density CRYOTESTLAB

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CRYOGENIC-VACUUM THERMAL TESTING •

Directly measure heat flow rate (Q) by LN2 boiloff calorimetry: calculate q and ke

•

Efficient, reliable testing of all types and configurations of thermal insulation materials and systems

•

ASTM International consensus technical standards C1774 and C740 Example: ASTM C1774 Annex A1 Cylindrical, Absolute

CRYOTESTLAB

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o o o o o o

Two layers of Cryogel 20-mm total thickness Thermocouples between layers Precision butt-joints Staggered seams Secured with multiple copper wires

CRYOSTAT-100 TEST SPECIMEN For seven test series, A194 – A200

CRYOTESTLAB

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THERMAL DATA •

Multi-mode heat transfer

•

Composites (non-isotropic, inhomogeneous)

•

Layered systems with radiation shields

•

Individual materials - data needed

•

Systems - data needed

•

Comparison with other materials using standard data obtained using standard apparatus & method

•

Consider both ke and heat flux (q)

CRYOTESTLAB

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Effective Thermal Conductivities (ke) of Cryogenic Insulation Materials

Boundary temperatures 78 K & 293 K; nitrogen residual gas. See ASTM C1774.

Effective Thermal Conductivity (mW/m-K)

100

10

1 A102 Glass Bubbles (K1, 65 kg/m3) A103 Perlite Powder (132 kg/m3) A108 Aerogel Beads (Nanogel 80 kg/m3) A104 Spray-On Foam Insulation BX-265

0.1

A105 Spray-On Foam Insulation NCFI 24-124 A112 Aerogel Blanket (Cryogel, 133 kg/m3) C130 LCI (Layered Composite Insulation) C123 MLI (foil & paper) C135 MLI (double-alumized Mylar & net)

0.01 0.001

0.01

0.1

1

10

100

1000

10000

100000

1000000

Cold Vacuum Pressure (millitorr)

Ref: Fesmire, J.E., Standardization in Cryogenic Testing and Performance Data, 5/15/18 Insulation Systems CRYOTESTLAB Physics Procedia, Vol 67, 2015, pp. 1089-1097, http://dx.doi.org/10.1016/j.phpro.2015.06.205

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100 Notes: 1. Boundary Temperatures approximately 78 K & 293 K. 2. Residual gas nitrogen. 3. Legend data (25, 40, 55) means: 25 mm thickness, 40 layers, and 55 kg/m3 bulk density [x, n, ρ].

Effective Thermal Conductivity - ke (mW/m-K)

Cryostat-1 Data Summary 10

1

A114 Vacuum Only A104 Spray-On Foam BX-265 (25, 1, 42)

A194 Cryogel in Nitrogen (20, 2, 130) C134 Aerogel Beads (25, 1, 80)

C138 Silingel Aerogel Blanket (16, 2, 51) C139 Aerogel Composite Tape (26, 9, 170)

0.1

C130 LCI Mylar+Cab530 (22, 30, 50) C102 Aspen White + 10MLI (21, 11, 0.5)

C105 Aspen Gray + 10 MLI (29, 11, 0.4) C107 LCI#1 18 CabOSil (25, 18, 0.7)

C135 MLI DAM/Net LHC (7, 30, 4.2) C123 MLI Foil & Paper (25, 60, 2.5)

0.01 0.001

0.01 5/15/18

0.1 CRYOTESTLAB

1

10

100

1000

Cold Vacuum Pressure - CVP (millitorr)

10000

100000

1000000 25

100 Notes: 1. Boundary Temperatures approximately 78 K & 293 K. 2. Residual gas nitrogen. 3. Legend data (25, 40, 55) means: 25 mm thickness, 40 layers, and 55 kg/m3 bulk density [x, n, ρ].

Effective Thermal Conductivity - ke (mW/m-K)

Cryostat100 Data Summary 10

1

A114 Vacuum Only A104 Spray-On Foam BX-265 (25, 1, 42) A111 Aerogel Pyrogel Blanket (18, 6, 125) A112 Aerogel Cryogel Blanket (23, 2, 133)

0.1

A194 Cryogel in Nitrogen (20, 2, 130)

A198 Cryogel in Helium (20, 2, 130) A113 Cryogel + 15 MLI (22, 16, - ) A193 Aerogel Paper MLI Comp (5, 7, 1.4, 91)

0.01 0.001

0.01 5/15/18

0.1 CRYOTESTLAB

1

10

100

1000

Cold Vacuum Pressure - CVP (millitorr)

10000

100000

1000000 26

100 Notes: 1. Boundary Temperatures approximately 78 K & 293 K. 2. Residual gas nitrogen. 3. Legend data (25, 40, 55) means: 25 mm thickness, 40 layers, and 55 kg/m3 bulk density [x, n, ρ].

Effective Thermal Conductivity - ke (mW/m-K)

Cryostat500 Data Summary 10

A114 Vacuum Only

1

A104 Spray-On Foam BX-265 (25, 1, 42) G1-176 Cryogel 10201 Blanket (18, 2, 180) G1-190 ULD Aerogel Blanket (23, 8, 55) G2-109 Spaceloft Subsea Grey (20, 4, 152) G1-189 Subsea Grey + 20 MLI (23, 24, 153) G1-191 ULD Aerogel MLI (23, 25, 52)

0.1

G2-110 Primaloft + Super MLI (19, 14, 176) G2-111 Aerogel Paper MLI (23, 21, 53) G1-132 Aerogel LCI Proto #1 (23, 44, 59) G2-107 Windward TLC#3 (25, 40, 66) A102 Glass Bubbles K1 (25, 1, 65) Kaganer Line - ke (MLI Baseline)

0.01 0.001 5/15/18

0.01

0.1 CRYOTESTLAB

1

10

100

1000

Cold Vacuum Pressure - CVP (millitorr)

10000

100000

1000000 27

Example Cryostat-100 Data Summary: Calculation, Tabulation, and Reporting Method A193 Aerogel Paper MLI Comp (5, 7, 1.4, 91)

Test

Thin Aerogel Blanket / DAM Composite Aspen Aerogels 0.7 mm thickness aerogel thin blanket

estimated, based on delta-T ratio >>> actual, non-steady state, slightly out of range >>>

A194 Cryogel in Nitrogen (20, 2, 130)

Test

Cryogel x201 aerogel composite

15 17 16 16.2 14 2 13 13.2 3 12 4 11 5 10.2 6 18 7 9 8

2 layers of 10-mm blanket Aspen Aerogels May-15 18 tests

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CVP

CBT

WBT

Flow

Q

q

ke 2

x

µ 0.002 0.007 0.2 1 10 100 1000 760000 760000

K 78 78 78 78 78 78 78 78 78

K 294.1 293.7 291.9 292.7 294.9 291.3 289.6 293.0 274.8

sccm 163 187 198 408 2459 6265 9261 33790 31000

W 0.676 0.775 0.821 1.692 10.196 25.978 38.401 140.110 128.541

W/m 2.16 2.47 2.62 5.40 32.5 82.9 123 447 410

mW/m-K 0.050 0.057 0.061 0.126 0.750 1.94 2.90 10.4 10.4

mm 5.00

CVP

T6

WBT

Flow

Q

q

ke

x

µ 0.01 0.01 0.1 0.1 0.5 1 5 5 10 50 100 500 1000 5000 10000 50000 100000 300000 760000

K 230 231 229 229 226 224 210 213 210 201 202 204 205 210 211 210 209 204 206

K 293.0 294.0 294.0 294.0 294.0 294.0 292.0 294.0 294.0 294.0 294.0 294.0 292.0 293.0 293.0 293.0 293.0 291.0 295.0

CRYOTESTLAB

sccm 1358 1330 1445 1401 1362 1430 1694 1667 1948 2301 2876 4025 4530 5287 5690 6472 7483 9481 10886

W 5.631 5.515 5.992 5.809 5.648 5.929 7.024 6.912 8.077 9.541 11.925 16.690 18.784 21.923 23.594 26.836 31.028 39.313 45.139

2

W/m 16.7 16.4 17.8 17.3 16.8 17.6 20.9 20.5 24.0 28.4 35.4 49.6 55.8 65.2 70.1 79.8 92.2 116.9 134.2

mW/m-K 1.55 1.51 1.64 1.59 1.55 1.62 1.94 1.89 2.21 2.61 3.27 4.57 5.19 6.03 6.49 7.38 8.54 10.92 12.30

do

di

L

mm mm mm 177.13 167.13 1000 ΔT P&H K hours 216 24

do

di

L

mm mm mm mm 19.90 206.90 167.10 1000 ΔT P&H K hours 215 72

Ae

n

2

m 0.313 7 m g 246

Ae

n

2

m 0.336 m g 1

2

ρ bulk

ρ bulk

g/cc lbm/ft3 0.091 5.68 z z layers/mm layers/in 1.40 36

ρ bulk

ρ bulk

g/cc lbm/ft3 0.000 0.01 z z layers/mm layers/in 0.10 3

28

Macroflash Z0 Data Summary

Macroflash (Cup Cryostat) Z0 Series - Various Aerogel Materials Effective Thermal Conductivity - calibrated ke Boundary Temperatures 293 K / 78 K; Environment 760 torr GN2

30

27.7 26.5

25

calbirated ke (mW/m-K)

20.4

20 17.6

15 12.9

10

5

0

X-Aerogel, hg05p501-2 X-Aerogel, hg05p501-1 (88 kg/m3) (86 kg/m3) 5/15/18

CRYOTESTLAB

X-Aerogel, hg05r104-2 (135 kg/m3)

X-Aerogel, hg05r104-1 (144 kg/m3)

Cryogel, 2 layers (199 kg/m3) 29

Macroflash Z1 Data Summary

Macroflash (Cup Cryostat) Z1 Series - Various Aerogel Materials Effective Thermal Conductivity - calibrated ke Boundary Temperatures 293 K / 78 K; Environment 760 torr GN2

30

27.9

25.0

28.1

27.9

28.3

25.0

25

calbirated ke (mW/m-K)

20.9

19.8

20

18.6

14.9

15 13.2

13.2 12.2

12.4

12.1

10

5

0 Cryogel 2 Cryogel 2 Cryogel x201 Cryogel x201 Primaloft ULD Aerogel Aerogel paper AeroZero PI AeroZero PI X-aerogel Layers (0 psi) layers (2 psi) #2 (1 Layer) #3 (1 Layer) Thin Aerogel Gray (3 0.7-mm white Flexcon Sheet Flexcon Sheet Yellow Disk layers) (10 stack) (20 stack) (20 stack) GRC (Z314)

5/15/18

CRYOTESTLAB

X-aerogel X-aerogel FX P X-aerogel FX P X-aerogel FX P X-aerogel FX P Yellow Disk Tan Disk #1 Tan Disk #1 Tan Disk #2 Tan Disk #3 GRC (Z315) (Flexcon) (Flexcon) (Flexcon) (Flexcon)

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AEROGEL COMPOSITE BLANKET & FIBER MATRIX Silica aerogel with fiber matrix reinforcement (Cryogel® by Aspen Aerogels) Single fiber: 15 µm dia. (equivalent to ~800 pores of aerogel) CRYOTESTLAB

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SUMMARY OF CRYOSTAT-100 TEST RESULTS FOR CRYOGEL IN DIFFERENT GAS ENVIRONMENTS o Variation of ke with CVP

o Boundary temperatures: 293 K / 78 K o Residual gas: as indicated

o CO2 Testing:

Solidification of CO2

50 mtorr

o N>H = no-vacuum to high-vacuum direction of testing o H>N = high-vacuum to no-vacuum direction

Liquefaction of Argon

o He versus N2 @ 760 torr:

o +124% (2.2x) for Cryogel o +538% (6.4x) for gas only

CRYOTESTLAB

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SUMMARY OF CRYOSTAT-500 TEST RESULTS FOR FIBER MATRIX MATERIAL IN COMPARISON WITH CRYOGEL He

o Flat plate boiloff calorimeter (absolute)

o ASTM C1774, Annex A3 o Test specimens: 204-mm diameter by 18-mm thickness (two layers)

o Variation of ke with CVP

o Boundary temperatures: 293 K / 78 K o Residual gas: as indicated

o Fiber Matrix compared to Cryogel:

N2 5 mtorr

Cryogel reference

o 82% higher at 760 torr o 29% lower at HV

CRYOTESTLAB

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SUMMARY OF CRYOSTAT TEST RESULTS FOR CRYOGEL AEROGEL BLANKET AND FIBER MATRIX MATERIAL Cryostat Test Specimen*

ke (mW/m-K) for select CVP (torr)