Transcript Document

IR&D Studies of
Light Weight Ablator
for Future Reentry Capsule Heatshield
IHI AEROSPACE Co., Ltd.
Kenichi HIRAI
2012.6.21
JAXA
Yuichi ISHIDA, Toshio OGASAWARA, Takuya
AOKI, Tetsuya YAMADA, Kazuhisa FUJITA,
Toshiyuki SUZUKI
1.Objective of this study
2
HAYABUSA
(300MJ/m2,53%)
Galileo
Genesis
Pioneer Venus
MER
MPF
Mars Viking
Stardust
Apollo
Reduction to
1/3 is required
Development
of new LWA
HAYABUSA
Successfully returned to
Earth in June 2010
HAYABUSA-2
To be launched in 2014
CFRP is derived from
SRM nozzle material
Reliable but
heavy!
【Source】 Laub & Venkatapathy：”Thermal Protection System Technology Facility Needs
for Demanding Future Planetary Missions”, International Workshop on Planetary Probe
Atmospheric Entry and Descent Trajectory Analysis and Science, (2003)
The Possible Future Directions
Large Capsule
Tiled LWA
Reentry Capsule Size DIA
（
）
4m
HTV-R
2017
LWA
2m 0.3～0.4
MSL
2013
CEV
2011
3
PICA
0.3
AVCOAT
0.5
LWA
0.3～0.4
PostGENESIS HAYABUSA-2 ?
2004
>2015
ASTERM
0.3
Marco-Polo
2018
1m
STARDUST
2006
HAYABUSA-2
0.5m
2015
<5
PICA
0.3
CFRP
1.3
Small Capsule
One-Piece
CFRP
> 20
5～10
10～20
Peak Heat Flux（MW/m2）
2. Our Strategy(1/2)
Carbon Preform（0.15<ρ<0.3）
CBCF (Carbon Bonded Carbon Fiber)
x
FIBERFORM
CALCARB
RVC (Reticulated Vitreous Carbon)
Grafoam
JFOAM
Resin Impregnation
Phenolic
SC-1008
Polyimide
JAXA Original
LWA
(0.25<ρ<0.4)
1. Issues of Imported
preforms
Expensive
Long Delivery Time (EL)
Sustainability
2.Persuit of unique LWA
Unique Preforms(RVC)
I don’t want to imitate PICA
3. Preform microstructure
Tailoring for successful
JAXA PI impregnation
Development of
Domestic RVC
JFOAM
4
2. Our Strategy(2/2)
Imported Preform
 CBCF
 RVC
Hopefully
improve
5
Domestic Preform
 RVC
F/B
Resin Impregnation
 Phenolic
 Polyimide
Process
is good?
Resin Impregnation
 Polyimide
Same Process
LWA
LWA
2nd Step
(22cm×22cm×5cm)
3rd Step
Arcjet Test
(12cm×12cm×5cm)
F/B
3. Overview (1/3)
candidate carbon preforms
6
CBCF
Carbon Bonded
Carbon Fiber
Carbon
Preform
（ρ<0.2）
Chop/Milled Fibers
Connected by
Phenolic Resin
【Source】：Lachaud et al : “Validation of a Volume-Averaged FiberScale Model for the Oxidation of a Carbon-Fiber Preform”, AIAA
42nd Thermophysics Conf 2011 (Extended Abstract).
RVC
Reticulated
Vitreous Carbon
500μm
Grafoam（ρ=0.16）SEM photo
3. Overview (2/3)
JAXA Polyimide Resin Impregnation
s-BPDA / BAFL / DMAc
Solution
Stir
Gellant
60-80℃
RT
Resin Solution
sufficiently long gel time (several Hrs)
Gelation at RT!
Reliable Process!
s-BPDA
BAFL
Resin Impregnation
Cure
vacuum
240℃,air
Remove
Solvent
50-200℃
vacuum
LWA
After Gelation
Gelation
RT, air
7
3. Overview (3/3)
JAXA Polyimide Raw Material Cost
Raw Material
Cost for
□25cm×5cm
Panel Fabrication
(10,000Yen)
JAXA/PI
In the Past
JAXA/PI Price
will be
comparative
to SC-1008!
JAXA/PI
Expected
in 2012?
Phenolic
SC-1008
8
4.Validation of Resin Impregnation Process
Imported Preform based LWA
9
Fabrication(1/6)
Candidate Carbon Preforms
Fabrication Matrix of LWA
Bulk Density
[g/cm3]
Polyimide
Resin
Phenolic
Resin
Imported RVC
(Grafoam FPA-10)
0.18
Imported RVC
(Grafoam FPA-10)
NA
○
Imported CBCF
(CALCARB 18-2000)
0.19
Imported CBCF
(CALCARB 18-2000)
○
○
Domestic RVC
(JFOAM-1, -2, -3)
○
○
Domestic CBCF
NA
NA
Domestic RVC
(JFOAM-1, -2, -3)
Domestic CBCF
0.15,
0.21, 0.28
NA
RVC : Reticulated Vitreous Carbon
CBCF : Carbon Bonded Carbon Fiber
LWA : Low Weight Ablator
4.Validation of Resin Impregnation Process
Imported Preform based LWA
10
Fabrication(2/6)
CBCF/Preform
Size : 22cm×22cm×5cm
Weight : 473.4g
Bulk Density : 0.196g/cm3
CBCF/PI LWA
Size : 21.98×21.99×4.65cm
Weight : 799.7g
Bulk Density : 0.356g/cm3
4.Validation of Resin Impregnation Process
Imported Preform based LWA
11
Fabrication(3/6)
21-38
220～250mm
48-56
42
10.5-19
21
Data Scatter
< ±3% !
5
ρ=0.36
4
10
3
C1
2
B1
B2
C3
1
2
7
12
4
C2
0 1
3
5 B3
11
A3
-1
9
6
8
-2 A1
-3
A2
-4
-5
0 1 2CALCARB
3 4 5 6 /7 polyimide
8 9 10 11 12 13
Density Dispersion ［％］
Density Dispersion ［％］
220～250mm
24-28
10.5-19
1cm cubic
5
ρ=0.28
LWA test specimen
4
3
2
B3
A2
B1
1
1cm cubic2 3
6 7 C2 9
0 A1
11 12
A3
5
8
LWA test specimen B2
C1
-1
4
10
-2
C3
-3
-4
-5
0 1 2 3Grafoam
4 5 6 /7phenolic
8 9 10 11 12 13
Validation of Resin Impregnation Process
Imported Preform based LWA
12
Fabrication(4/6)
Residual carbon ratio ［%］
within impregnated
“resin+solvent”
Residual carbon ratio ［％］
Residual carbon ratio ［％］
65% : Same as
genuine PI
Data Scatter is small,
so resin impregnation
process is judged
reliable
CALCARB / polyimide

Wfinal  Wpreform
Winitial  Wpreform
Charred Re sin

Re sin  Solvent
35% : lower than
genuine Ph
Grafoam / phenolic
4.Validation of Resin Impregnation Process
13
Imported Preform based LWA
Fabrication(5/6)
21-38
220～250mm
48-56
220～250mm
24-28
42
10.5-19
21
10.5-19
Same behavior
as genuine PI
100
95
90
85
80
75
70
0
200
400 600 800 1000 1200 1400
Temperature （℃）
CALCARB / polyimide
Low BP solvent
Is much contained?
105
W(T)/W0×100
［％］
W(T)/W0×100 （％）
W(T)/W0×100
［％］
W(T)/W0×100 （％）
105
100
A1
A2
A3
B1
B2
B3
C1
C2
C3
A1
95
A2
A3
90
B1
B2
B3
85
C1
C2
80
C3
75
70
0
200
400 600 800 1000 1200 1400
Temperature （℃）
Grafoam / phenolic
Thermal Conductivity ［W/m/K］
4.Validation of Resin Impregnation Process
14
Imported Preform based LWA
Fabrication(6/6)
0.4
0.3
Good
Insulative
Performance!
0.2
PICA Estimated
Grafoam / Ph ( ρ0.28)
CALCARB / PI ( ρ0.36)
JFOAM / PI ( ρ0.29)
0.1
0
0
100
200
300
400 500 600
Temperature ［℃］
LWA Thermal Conductivity
【Source】 Tran et al：” Phenolic Impregnated Carbon Ablators (PICA) as Thermal
Protection Systems for Discovery Missions, NASA TM 110440, (1997)
4.Validation of Resin Impregnation Process
Imported Preform based LWA
15
Fabrication(7/7)
2200
2000
1800
1600
1400
1200
1000
800
600
0
Repeatability of LWA
Temperature responses
is fairly good!
Measured
2Ap
2Aq
2Ar
Surface
Temp
Computed
600
20
40
Time ［sec］
60
Temperature responses
of LWA’s are well
predicted by the
present tentative
ablation calculation!
Measured
2Ap
2Aq
2Ar
Computed
15mm
25mm
Depth
15mm
500
80
400
Temparature ［℃］
Temparature ［℃］
Temperature Response of CALCARB/PI LWA
300
200
Depth
25mm
100
0
0
100
200
300
Time ［sec］
400
500
5.Domenstic RVC based LWA Development
16
Development of JFOAM(1/5)
Grafoam
JFOAM-1
CALCARB
Current
microstructure of
JFOAM is much
coarser than
existing imported
CBCF/RVC!
SEM Photographs of various kinds of lightweight carbon preforms
(Our RVC’s are designated as JFOAM-1(density=0.16g/cm3) )
5.Domenstic RVC based LWA Development
Development of JFOAM(1/5)
Similar Properties as Existing Carbon Preforms
17
5.Domenstic RVC based LWA Development
18
Development of JFOAM(1/5)
Fiberform（ρ0.17）
Fiberform（ρ0.14）
0.11
0.16
0.21
0.28
JFOAM bulk density vs thermal conductivity
【Source】 Tran et al：” Phenolic Impregnated Carbon Ablators (PICA) as Thermal
Protection Systems for Discovery Missions, NASA TM 110440, (1997)
5.Arcjet Tests of LWA(1/6)
19
Test Conditions of Arcjet Experiments
CW Heat Flux ［MW/m2］
Impact Pressure ［KPa］
Heating Time ［s］
#1
1.8
4.4
30
#2
3.4
13.7
30
#3
6.0
19.6
30
LWA
Specimen
65mm
T/C φ0.2mm
Type-K
50mm
Flat Faced
Specimen
Bakelite
Holder
5.Arcjet Tests of LWA(2/6)
JFOAM/PI
Before Test
JFOAM-3/PI
After Test: 3.4MW/m2 x 30s
JFOAM-3/PI
After Test: 6MW/m2 x 30s
20
5.Arcjet Tests of LWA(3/6)
21
JFOAM-1 / PI
6MW/m2x 30s
Spallation by
Larger Particles
(a)
JAXA/ISAS
Arcjet Tests Photographs
By Degital Camera
CALCARB / PI
6MW/m2x 30s
Spallation by
Smaller Particles
Rate）
Y（Recession
[mm/s]
Recession Rate
(mm/s)
5.Arcjet Tests of LWA(4/6)
PICA Recession Characteristics
0.2
0.15
Arcjet Data
AHF271
Computed
TITAN
0.1
Y=0.2326X
P:pressure(KPa)
q:heat flux(W/cm2)
0.05
0
0.2
0.4
0.6
0.8
0.33
exp(-5.93/q0.25) 0.25））
X（pp0.33×exp（-5.93/q
1
Empirical Expression for Surface Recession Rate of PICA
Hwang, et al., Race Towards Launch: Qualifying the Mars Science Laboratory
Heatshield in under Ten Months, ICCE-17(17th International Conference on
Composite/ NANO Engineering, (2009)
22
5.Arcjet Tests of LWA(5/6)
Recession of JFOAM/PI LWA
Recession Rate （mm/s）
0.5
PICA Estimated
Grafoam / Ph （ρ0.28）
CALCARB / PI （ρ0.36）
JFOAM / PI （ρ0.29）
JFOAM / PI （ρ0.34）
JFOAM / PI （ρ0.37）
0.4
0.3
0.2
0.1
0
1
2
3
4
5
6
7
Cold Wall Heat Flux （MW/m2）
Our LWA’s surface recession rates are comparative
to PICA, when the density values are around 0.36!
23
5.Arcjet Tests of LWA(6/6)
Recession of JFOAM/PI LWA
24
120
ρcV ［g/m2/s］
100
80
Grafoam / Ph (ρ0.28)
CALCARB / PI （ρ0.36）
JFOAM / PI (ρ0.29)
JFOAM / PI (ρ0.34)
JFOAM / PI (ρ0.37)
HAYABUSA-CFRP
60
40
20
0
0
1
2
3
4
5
6
7
Cold Wall Heating Rate ［MW/m2］
For the moment, char density values of RVC/LWA’s are
somewhat ambiguous, however, recession mass flux values
of RVC/LWA seem to be almost constant. Are they
independent of the microstructures?
5. Conclusions & Future Works


We are currently conducting IR&D activity towards domestic
RVC/LWA with density 0.3-0.4g/cm3 for future reentry missions.
From the experiences of fabricating LWA panels of 22cm x 22cm x
5cm and density measurements, we have confirmed that our resinimpregnation process for LWA is quite stable and reliable.
 CALCARB/PI <±3%




25
Grafoam/Ph
<±3%
The insulative peformance of current LWA’s is judged acceptable.
But the Arcjet tests revealed signs of spallation-driven recession
especially for our domestic RVC/LWA, which may be attributed to
the coarse microstructures peculiar to our current RVC’s.
Therefore, further modifications for our RVC are currently
underway in order to improve recession resistance.
 Fine Cell Structures
The Possible Future Directions
Fine Cell Structured JFOAM
1mm
Current JFOAM
(ρ0.22)
1mm
Fine Cell
Structure
Fine Cell Structured
JFOAM (ρ0.20)
26
Thank You
for Your Attention!
Any Questions?