26H01
氷の自励振動成長―Ice Crystal 2 実験の成果―○古川義純，長嶋剣，麻川明俊，中坪俊一，村田憲一郎，佐崎元（北大低温研），吉崎泉，田丸晴香（JAXA），島岡太郎（JSF），曽根武彦（JAMSS），真木孝雄，山本明日佳（オリンパス）

Self-Oscillatory Growth of Ice -Ice Crystal 2 Experiments○Yoshinori FURUKAWA, Ken NAGASHIMA, Harutoshi ASAKAWA, Shunichi NAKATSUBO, Kenichiro
MURATA, Gen SAZAKI (Hokkaido Univ.), Izumi YOSHIZAKI, Haruka TAMARU (JAXA), Taro SHIMAOKA(JSF), Takehiko SONE (JAMSS), Takao MAKI, Asuka YAMAMOTO (Olympus)

1. Introduction
Ice Crystal 2 experiments were conducted in KIBO of ISS.
Free growth of ice crystals in a supercooled bulk watercontaining a small amount of antifreeze glycoprotein (AFGP),
which was a functional biomaterial to inhibit the freezing of fish
body under the sub-zero temperature condition, was observed
in-situ using a newly-developed optical system. Experiments
were repeated more than originally intended repeat count in the
period from November 2013 to June 2014. Ice crystal growth
were successfully observed and clear interference fringes wereobtained on the ice(basal)/water interfaces. We describe an
overview of experimental results in this presentation.

2. Experimental Procedures
The experimental cartridge, which was newly developed forthis experiment, was composed of two parts, as was the
cartridge used for first space experiment1), but the two parts
were extensively modified for the second experiment. For thegrowth apparatus of an ice crystal, a spherical growth cell (40mm in diameter) was made and it was equipped with therotating mechanism of a glass capillary around its axis. As the
optical system to observe ice crystal growth, a Michelson-type
interference microscope combined with a phase contrast
microscope was installed in the cartridge. These systems allow
observation of step migrations on the growing basal face andmeasurement of growth velocity at the same time.
The cartridge was transported to the ISS in August 2013 andthe first experiments were started at the end of this month.
However, our experiment fell into difficulties in the power
supply system immediately after starting experiments.
Fortunately, experiments could be started again after
troubleshooting, and for the last time 124 growth experiments
were carried out in space under various supercooling conditionsin the range between 0.1 and 1 K. Ice crystal growth wasobserved in almost every experiment, and interference fringes
on the basal faces were successfully observed in more than 20%of the experiments.

directional growth experiments conducted in a thin growth cellwith no convection in the cell2). Zepeda et al.3,4) directly
observed that the prism faces for which growth had been
stopped by adsorption of AFGP molecules started to grow again
along with desorption of AFGP molecules from the interface.
These observations indicate that the growth velocities of prism
faces should not be constant but fluctuate with growth time.
This kind of fluctuation may give suggestions for the selfoscillatory growth of a prism face.
In the present space experiments, clear interference fringes
were observed on the basal faces of growing ice crystals.
Furthermore we observed the fluctuation of fringe migrations.
We can estimate the growth rates of basal faces by analyzing the
movement of interference fringes observed. Consequently, thisexperimental result means that the growth rate of a basal facefluctuates with the growth time under the microgravity
condition in which the disturbances like thermal convection
were completely taken out.
The mechanism for the self-oscillations of growth rates
should be explained in relation to the adsorption-desorption
processes of AFGP molecules on the growing interfaces.
Consequently, the experimental data obtained in space will
provide direct information about why adsorption and desorption
can occur periodically on both prism and basal interfaces of anice crystal. Such information is expected to contribute toelucidation of the mechanism of the antifreeze effect.

References
1)

E. Yokoyama, I. Yoshizaki, T. Shimaoka, T. Sone, T. Kiyota and Y.
Furukawa: J. Phys. Chem., B115 (2011) 8739.

2)

Y. Furukawa, N. Inohara and E. Yokoyama: J. Cryst. Growth, 275(2005) 167.

3)

S. Zepeda, E. Yokoyama, Y. Uda, C. Katagiri and Y. Furukawa:
Cryst. Growth Des., 8 (2008) 3666.

4)

3. Experimental Results
Time fluctuation of growth rate for the prism face of an ice
crystal in the AFGP solution was first observed in one-

－10－

S. Zepeda, Y. Uda and Y. Furukawa: J. Jpn. Asso. Cryst. Growth,
35 (2008) 151.

26H02微小重力環境下で TLZ 法により成長した SiGe 結晶内組成分布の数値解析○住岡沙羅，阿部敬太，杉岡健一，久保正樹，塚田隆夫（東北大院工），木下恭一，荒井康智，稲富裕光（宇宙航空研究開発機構）

Numerical Study on the Composition Distributions in SiGe Crystals Grown by TLZ Method
under Microgravity○Sara SUMIOKA, Keita ABE, Ken-ichi SUGIOKA, Masaki KUBO, Takao TSUKADA (Tohoku Univ.),
Kyoichi KINOSHITA, Yasutomo ARAI, Yuko INATOMI (JAXA)

1. Introduction2) K. Abe, S. Sumioka, K. Sugioka, M. Kubo, T. Tsukada, K.

The second microgravity experiment on SiGe crystal growthby the traveling liquidus-zone (TLZ) method has been carriedout aboard the Japanese Experiment Module “Kibo” in theInternational Space Station in July 20131). In this work, we
numerically investigated the transport phenomena andsolidification taking place in this microgravity experiment indetail, using a mathematical model developed by the present
authors2). Particularly, the axial and radial composition
distributions of Ge in the crystal were discussed, comparing thenumerical results with the experimental ones.

Kinoshita, Y. Arai, and Y. Inatomi, J. Cryst. Growth, 402 (2014) 71
3) K. Kinoshita, Y. Arai, Y. Inatomi, T. Tsukada, S. Adachi, H. Miyata,
R. Tanaka, J. Yoshikawa, T. Kihara, H. Tomioka, H. Shibayama, Y.
Kubota, Y. Warashina, Y. Sasaki, Y. Ishizuka, Y. Harada, S. Wada,
C. Harada, T. Ito, M. Takayanagi, and S. Yoda, J. Cryst. Growth,388 (2014) 12
Temperature [K]5-15 K/cm
Distance from the bottom of Si seed [mm]5.1 mmr

2. Mathematical model

2.0 mmz

The axisymmetric model used here can predict thetemperature distributions in the BN crucible, Si seed, Si feed,
SiGe melt and crystal, the composition distributions of Ge in themelt, and the shapes of the melt/SiGe crystal and melt/Si feed in

Si seed
30 mm

Ge composition [-]0.55

3. Results and discussion

0.51

0.49
experimental results1)
numerical results

0.47
0.45
2

4

6

8

10

Growth length [mm]Fig.2 Axial composition distributions of Ge in SiGe crystals

Ge composition [-]

(a)
0.55
0.50
0.45

-6

Ge composition [-](a) 4.0 and (b) 7.5 mm in Fig.2. From the figure, it is found thatthe mean values of Ge compositions depend on the growth
length, whereas the radial distributions are kept relatively
uniform throughout the entire crystal.

-4

-2

0

2

4

6

Radial distance [mm](b)

Figure 3 shows the numerical and experimental results of theradial composition distributions of Ge at the growth lengths of1) K. Kinoshita, Y. Arai, T. Tsukada, Y. Inatomi, H. Miyata, and R.
Tanaka, J. Cryst. Growth (Submitted)

0.53

0

cartridge surface, in which the BN crucible in Fig.1 is included,
due to oxidization, similarly to the first microgravity
experiment3).

ReferencesBN
crucibleFig. 1 Schematic diagram of TLZ method

Fig.1, using the finite difference method on the basis ofboundary-fitted coordinate transformation2). The temperature at
the outer wall of the BN crucible was determined by a global
heat transfer analysis in a gradient heating furnace used in the
microgravity experiment, using FLUENT 12.1.
Figure 2 shows the numerical and experimental results of theaxial composition distributions of Ge along the central axis of
the grown crystal. Both the composition distributions show theU-shaped one at the early to middle stage of the growth, but
finally become constant. The origin of such a U-shaped
distribution was considered to be the emissivity change of the

Si feed
57 mm

SiGe melt
21 mm

0.55
0.5
experimental results1)
numerical results
0.45
-6

-4

-2

0

2

4

6

Radial distance [mm]Fig.3 Radial composition distributions of Ge in SiGe crystals(a) growth length: 4.0 mm, (b)7.5 mm－11－

26H03微小重力下における TLZ 法による均一組成 SiGe 結晶育成の研究（その 2）○木下恭一 1，荒井康智 1，稲富裕光 1，塚田隆夫 2，宮田浩旭 3，田中涼太 3，阿部敬太 2，住岡沙羅 2（1::宇宙航空研究開発機構，2:東北大学大学院工学研究科，3:（株）エイ・イー・エス)

Growth of Homogeneous SiGe Crystals by the TLZ Method in Microgravity (Report-2)○K. KINOSHITA1, Y. ARAI1, Y. INATOM1, T. TSUKADA2, H. MIYATA3, R. TANAKA3, K. ABE2,
S. SUMIOKA2 (1: Japan Aerospace Exploration Agency, 2: Dept. Chem. Eng. Tohoku Univ., 3: AES Co. Ltd.)

1. Introduction
SiGe crystal growth experiments aboard the “Kibo” in the
ISS were carried out for evaluating the growth model of thetraveling liquidus-zone (TLZ) method. Results of threeexperiments are summarized along with the growth conditions.

2. Experiments
10 mm diameter Si1-xGex (x ~ 0.5) crystals were grown by
the TLZ methods. Orientation of the Si seed was <100>. Thezone former Ge was polycrystalline. After removing the surface
contamination and the oxide layer by etching in an acid solution,
a 30 mm long Si seed, a 20 mm long Ge zone forming material
and a 57 mm long Si feed were put into a boron nitride (BN)crucible with a carbon spring for avoiding free melt surface. The
crucible was vacuum sealed in a quartz ampoule at about 1×10 Pa. The ampoule wrapped by ZrO2 cloth was then inserted
into a metal cartridge. The assembled metal cartridges were
heated in the gradient heating furnace. Growth conditions are as
follows, temperature gradient: 9℃/cm, heater translation rate
0.1 mm/h, freezing interface temperature: 1107℃, experimentperiod: 72～124 h. In the second and third experiments, heatertiming of heater temperature adjustment did not coincide withthe timing of the emissivity change. Emissivity change may
depend not only on heating period but also on the level of
vacuum in the furnace chamber. Then, timing of heatertemperature change to cancel the emissivity change is very
difficult. Cartridges with oxidized surface may be useful toavoid this effect.
Growth length was observed to be 14.5 mm, which iscomparable to the expected length of 15 mm. Growth interface
shape was observed by the striation2) which was caused by step
temperature changes of 1oC. At the seed/crystal interface, it wasconvex toward the melt. The seed/crystal interface shape may be
resulted by the melt flow around the seed through a gap between
the seed and the crucible wall at the start of the crystal growth.
The interface gradually changed to a flat shape according as the
crystal growth proceeded. This tendency was similar to thesecond sample, but the radial compositional homogeneity wasbetter in the third experiment since the interface curvature is lessthan the second experiment. In the presentation, results of threeexperiments will be compared and discussed.
Seed
SiGe crystal Quenched meltFeedtemperatures were adjusted so as to cancel the oxidation effectof the cartridge surface. The returned samples were analyzed byan electron probe microanalyzer and by an electron backscatter
diffraction after cutting parallel to the growth axis and polishing.

Fig. 1.10Outer
mm view of a sample of the third experiment.

3. Results and discussion

Fig. 1. Outer view of a sample of the third experiment.

The outer view of a sample obtained in the third experimentis shown in Fig. 1. A seed, SiGe crystal region, quenched melt
and a Si feed are indicated in the figure. No missing part, large
voids and major cracks were detected in a cross section of thegrown crystal. No free surface of the melt would be existed
during the experiment since a trace of flown melt which was
pushed by a carbon spring toward the seed was observed on thefeed surface. Marangoni convection would, therefore, be
suppressed in the experiment.
The axial Ge concentration profile is shown in Fig. 2.

Ge concentration (at%)

55

51

49.0 ±2.0

49

47
45
28

Average Ge concentration was 49.0±2 at% and a dip of Ge
concentration was observed. It is shown that the dip is related totemperature rise in the cartridge due to emissivity change of the
cartridge surface by oxidation1). Therefore, heater temperatures
were adjusted to cancel the emissivity change but the effect ofemissivity change was not canceled. The results implied that

53

30

32

34

36

38

40

42

44

Distance from the tip (mm)F. 2. Axial Ge concentration profile.

Fig. 2. Ge concentration profile along the growth axis.
References
1) K. Abe et al., J. Crystal Growth 402 (2014) 71.
2)

－12－

Y. Arai et al., NCCG-44 予稿 (2014).

46

26H04
観測ロケットで得られる微小重力環境下での気相からの均質核生成の“その場”観察実験○木村勇気，田中今日子（北大），塚本勝男（東北大・大阪大），竹内伸介，稲富裕光（JAXA）

In-situ Observation of Homogeneous Nucleation from Vapor Phase under
Microgravity Prepared by a Sounding Rocket○Yuki KIMURA, Kyoko K. TANAKA (Hokkaido Univ.), Katsuo TSUKAMOTO (Tohoku Univ, Osaka Univ.),
Shinsuke TAKEUCHI, Yuko INATOMI (JAXA)

1. Introduction

microgravity experiment using the sounding rocket S-520-28.

It is difficult to find homogeneous nucleation event on the
Earth because there are lots of heterogeneous nucleation site.
In case of a nucleation event around dying star, there is almost
no solid materials available for heterogeneous nucleation siteand, therefore, homogeneous nucleation govern the propertiesof cosmic dust, which is produced from a supercooled gas inoutflow from dying stars or in a gas plume after shock wave
heating in the primitive solar nebula. To know the formation
process of cosmic dust particles via homogeneous nucleation,
we have to obtain the physical parameters, especially surface
free energy and sticking probability, of nanometer sizedparticles, because of the size of cosmic dust is typically less than
100 nm. To determine the physical parameters of nanoparticles,
we developed an in-situ observation system of temperature andconcentration during homogeneous nucleation in vapor phaseusing interferometry.

3. Experimental procedure

2. Benefits of microgravity experiment
We produce nanoparticles from a supercooled vapor after
evaporation of a selected material by electrical heating in a gas
atmosphere in the laboratory. Using the interferometry, surface
free energy and sticking probability of manganese nanoparticle
were determined from timescale for gas cooling andcondensation temperature based on nucleation theories 1).
However, in case of 1 G, convection of gas atmosphere causedby thermal heating of an evaporation source generates
heterogeneity of nucleation environment. In addition, there is ahigher possibility of that number density of nuclei decreases byfusion growth by collide each other after a stage of nucleation 2).
This fusion growth may be one of reasons of large differences ofnucleation rates between experiments and theories. Microgravity
environment will resolve these difficulties of 1 G experiments.
Large difference of reported sticking probabilities obtained by
microgravity (~10-5) 3) and 1 G (~1) 4) is also give us a
motivation to do microgravity experiment.
If same kinds of experiments are performed in microgravity,
evaporated vapor will diffuse uniformly and the temperature
profile will become concentric around the evaporation source.
As the result, nucleation will occur at the same condition, i.e.,same supersaturation. Then, we can obtain physical propertiesof nanoparticles more precisely. Therefore, we performed a

We prepared specially designed three experimental systems,
named DUST 1 to 3, with almost same configuration except
evaporation source and gas pressure in the chamber were
installed into the rocket. The each system has a double
wavelength Mach–Zehnder-type interferometer with a working
chamber and a camera recording system on an aluminum baseplate. The evaporation source and gas atmosphere of eachsystem are tungsten without iron and a gas mixture of oxygen(4.0 × 103 Pa) and argon (3.6 × 104 Pa) for DUST 1, iron andargon (2.0 × 104 Pa) for DUST 2, and iron and argon (4.0 × 10 4Pa) for DUST 3. Argon gas works as a buffer gas to shorten themean free path of evaporated vapor. Evaporated vapor oftungsten oxide or iron was diffused, cooled and nucleated in thegas atmosphere. Changes in refractive index are induced not
only by variations in temperature, but also by variations in theconcentration of iron vapor. Because the Mach–Zehnder-type
interferometer has two lasers of polarized green and red, thetemperature and concentration could be determined
simultaneously from a movement of the interference fringes.

4. Results and discussion
Using a specific timescale for gas cools, we calculated theequations governing the time evolution of the gas number
density of Fe atoms and the nucleation rate. From thecomparisons between the numerical simulations and theexperimental results, we can determine the sticking probability
for Fe. Then, we obtain the nucleation temperatures, which havevery large supercooling larger than 1000 K, and sticking
probability as small as 10-4 for iron.

References
1)

Y. Kimura, K. K. Tanaka, H. Miura, K. Tsukamoto, Crystal
Growth & Design, 12 (2012) 3278.

2)

Y. Kimura, In: Nanodust in the Solar System: Discoveries andInterpretations. Eds. Ingrid Mann, Nicole Meyer-Vernet, Andrzej
Czechowski, Springer-Verlag (2012) p. 31-46.

3)

B. P. Michael, J. A. Nuth III, L. U.Lilleleht, The AstrophysicalJournal, 590 (2003) 579.

4)

－13－

S. Tachibana, H. Nagahara, K. Ozawa, Y. Ikeda, R. Nomura, K.
Tatsumi, Y. Joh, The Astrophysical Journal, 736 (2011) 16.

26H05
NanoStep プロジェクトから得たもの〇塚本勝男（東北大），鈴木良尚（徳島大），三浦均（名市大），吉崎泉（JAXA）

What we have learned from the NanoStep project〇Katsuo TSUKAMOTO (Tohoku Univ.), Yoshihisa SUZUKI (Tokushima Uni.),
Hitoshi MIURA (Nagoya City Univ.), Izumi YOSHIZAKI (JAXA)

Probably this improved effect would be valid only for theseWe have been interested in the growth mechanism oflysozyme crystals under microgravity. This is because for many

impurities with larger diameter than protein molecules.

years perfection of space grown crystals claimed to be better(3) Supersaturation distribution over growing crystal surface

than earth grown crystals. However there are also many cases

was unexpectedly more homogeneous in microgravity

showing opposite results. To clarify the factors controlling theleading to much less supersaturation decrease if measured

perfection, we started NanoStep Project employing in-situ

from the edge to the middle of the crystal surface. Thisobservation method of crystal growth, in which growth rate vswould give rise to the improved stability of crystal face,supersaturation has successfully been measured for the first time

which possibly results in the improved perfection ofthrough observation of the surface features were also observed

crystals.

by laser interferometry in Kibo in 2012 [1]. The former rate(4) Some other unexpected results were obtained: effect ofmeasurement and the latter observation of surface features arecooperation spiral growth on the growth rate and slope ofimportant respectively for the analysis of growth kinetics andspiral hillocks, dislocation nucleation at the seed crystal

for the study of effect of impurity adsorption and effect of

surface and so on.
These experimental results show that Kibo becomes a realconcentration inhomogeneity around a crystal.
The experiments finished successfully but the results obtainedlaboratory in which we can run experiments in the same or evenfrom NanoStep project were much better than the expectation

better conditions so that we can perform high level experimentsfrom ground-based experiments. We therefore had to repeat

as we do in our laboratories on the ground.

more reference experiments later on for the comparison.
[1]

The results are summarized:(1) The growth rate in spiral growth regime under microgravity
is higher than that in gravity if we compare the growth rateof crystals from the same purity solutions. The growth
regime has usually been used to grow protein crystals forI. Yoshizaki, K. Tsukamoto, T. Yamazaki, K. Murayama, K.
Oshi, S. Fukuyama, T. Shimaoka, Y. Suzuki, M. Tachibana,
Growth rate measurements of lysozyme crystals under
microgravity conditions by laser interferometry, Review of
Scientific Instruments, 84 (2013).
[2] Y. Matsuura, A.A. Chernov, Morphology and the strengthof intermolecular contacts in protein crystals, Acta
crystallographica. Section D, Biological crystallography,
59 (2003) 1347-1356.

structural analysis.
(2) The difference of the growth rate is attributed to theanisotropic adsorption of dimer impurities along growth
steps parallel to the <1-11> and the <-111> directions, theformer of which is nearly equal in the macro-bond strength[2] to the latter but molecular arrangement at each step
fronts is different. As long as we do experiment in gravity,
crystals experience stronger effect of impurity effect.

－14－

26H06
地上と無重力での結晶表面の二次元過飽和度および成長速度分布の測定○村山健太（名古屋大），塚本勝男（東北大），横山悦郎（学習院大）

Measurement of the Growth Rate and Supersaturation Distribution at the Crystal Surface on
the Ground and Microgravity○Kenta MURAYAMA (Nagoya Univ.), Katsuo TSUKAMOTO (Tohoku Univ.),
Etsuro YOKOYAMA (Gakushuin Univ.)

1. Introduction
The convection in solution is restrained in microgravity
environment so that the solute concentration is decreasing
towards the crystal-solution interface because the crystal
consumes solute in the solution as it grows (Berg effect). On
the other hand, the convection disturbs the concentration fieldaround the crystal on the ground. Therefore, the mechanism of
the crystal growth on the ground and in microgravity should be
different. To discuss this problem, direct measuring of theconcentration filed and growth rate is very important. However,there is no direct observation of the relationship between growthrate and concentration field in microgravity or on the ground.

measured to be very small (only about 2.4%) compared withthat of under gravity. Normal growth rate distribution is almost
uniform on the crystal surface in microgravity so that flat crystal
face can be maintained.
According to this result, the upward flow due to the convection
has the stronger influence than the Berg effect on the stability ofa crystal surface.

2. Experiments
We carried out the microgravity experiment in the International
Space Station (ISS) that gives ideal environment without
convection. A protein crystal grows within the cell whose
temperature is controlled.
The "in-situ" observation of the concentration field around the
crystal and the measurement of the growth rate of (110) surface
were carried out by using the Mach-Zehnder and the Linnik
interferometer, simultaneously. The sample used for theexperiment is a tetragonal lysozyme (solution concentration 30
mg/ml, 50 mM Acetic acid buffer pH4.5, NaCl 2.5%). The
crystal growth cell was conveyed to ISS after enclosing a seed
crystal and solution on the ground. A seed crystal is put on thewall so that (110) surface becomes perpendicular to the optical
path of the Linnik interferometer. Changing the temperature ofsolution performs the variation of the supersaturation ofsolution.
Same experiment on the ground was carried out to see theeffect of the convection in solution.

Fig.1 The topography plot of crystal surface, the distribution of thesurface supersaturation and growth rate (a) on the ground and(b) in microgravity.

Fig.2 Supersaturation distribution above the (110) face of the lysozyme
crystal (a) on the ground (b) in microgravity.

3. Results and discussion
There is a large difference (about 16%) of the supersaturation
between the central and the edge on the ground, mainly becauseof the convection plume of solutal convection. As a result,almost twice as large growth rate arises at the edges of the (110)
surface as compared with the rate at the middle of the face, andthus flat crystal face cannot be maintained, leading to theinstability of the face.
In microgravity, convection is suppressed and thesupersaturation gradient along the surface was expected larger.
However the supersaturation difference was for the first time

References
1)

W. F. Berg: Proc. R. Soc. Lond. A, 164 (1938) 79.

2)

E. Yokoyama and T. Kuroda: Phys. Rev. A, 41 (1990) 2038.

3)

F. Bedarida: J. Cryst. Growth, 79 (1986) 43.

4)

K. Onuma, K. Tsukamoto and I. Sunagawa: J. Cryst. Growth, 89(1988) 177.

5)

K. Murayama, Katsuo Tsukamoto, Atul Srivastava, Hitoshi Miura,
Etsuro Yokoyama, and Yuki Kimura: Cryst. Res. Technol., 49(2014) 315.

－15－

26H07

宇宙実験を利用した実用 X 線構造解析向けタンパク質結晶化実験の 30 年とこれから
田仲 広明（（株）コンフォーカルサイエンス）

A Historical Perspective on Protein Crystallization in Space for Practical X-ray Structural
Analysis over the Past 30 years and Towards the Future
Hiroaki TANAKA (Confocal Science Inc.)

1. Space Experiment of NASA and ESA in the past
The first successful protein crystallization growth (PCG)
experiment in microgravity was performed in Spacelab by Littke
et al. 1) in 1983. Since then, many PCG experiments in
microgravity have been performed by NASA, ESA, RSA, JAXA
(NASDA) etc., but the impact of microgravity crystallization on
structural biology was not established for a long time. NASA
performed protein crystallization experiment for X-ray
diffraction analysis almost once in twice during 1990s. But in
2000, the National Research Council of the United States
reported that the impact of microgravity crystallization on
structural biology as a whole is extremely limited, and NASA
stopped protein crystallization experiment until recently. ESA
performed space experiment almost once a year during 1990s
and experimentally studied the effects of microgravity on
protein crystal growth. From these activities,, certain
mechanisms for the improvement of crystal quality werereported2,3,4).

2. Space Experiment of JAXA in the past and present
JAXA/NASDA has been conducting the protein
crystallization experiment in microgravity environment since
1992 (FMPT (STS-47)). In 1997, 15 protein samples werelaunched to space (STS-84). Through these experiences, it was
realized that specific crystallization techniques for microgravity
environment were mandatory. From 2002 to present, JAXA
conducted GCF, NGCF and PCG project to provide PCG
experiments for X-ray diffraction analysis combined with manytechnological developments. During these projects, we foundthat the biggest advantage of the PCG in microgravity is toimprove the maximum resolution of the crystals far beyond what
can be obtained from the terrestrially-grown best crystals5).
Simultaneously, the following concerns were arisen.
▪ In the laboratory, even if the protein sample is not so stable,
we may obtain a crystal suitable for X-ray diffraction
experiment. But for the space experiment, since it takes longer
from the launch to the recovery, the deterioration of theprotein sample may cause a difficulty of crystal growth.
▪ In the laboratory, even if the possibility of the crystal growth islow, we may obtain a crystal suitable for X-ray diffraction
experiment. But for the space experiment, it may end up withno crystal growth.
▪ In the laboratory, researchers usually use a vapor-diffusion

method for crystallization. But for the space experiment, it
may be better to use a liquid-liquid diffusion method to avoid
Marangoni convection. So, we have to acquire techniques forthe optimization of crystallization conditions and for handling
crystals, specialized for that method.
▪ It is said that microgravity effects on growing crystal is due tothe formation of protein and impurity depletion zones aroundthe growing crystal. Therefore the crystallization condition
which enhances these effects is favorable6,7). However for mostof the researchers, it is not necessary to pay attention to thiskind of matter on the ground. So we have to make efforts to
explain how important it is to optimize crystallization
condition suitable for space experiment.
Considering these problems, we have extensively supported
researchers from a proposal submission to X-ray diffraction datacollection. As a result, more effective usage of the microgravity
environment for crystallization has come true. So far, JAXA
space experiment has contributed to the structure analysis ofalmost 20 kinds of protein, resulting in the publication of paper
and PDB registration. Therefore, we believe that the reputationof the PCG experiment in microgravity has been favorablychanging.

3. Space Experiment in the future
The technique for protein crystallization experiment in space isstill developing; a crystallization condition optimization method
customized for each protein's property; a crystallization cellsuitable for growing large crystals for neutron diffraction
experiment, etc. Some of the accumulated knowledge bytechnical development for the space experiment so far can beapplied to the crystallization experiment in the laboratory. We
strongly convince that PCG in space is the final method toimprove the maximum resolution of the protein crystals, which
will contribute to the sub-Å structure analysis.

References
1)

W. Littke, C. J. John: Science 225 (1984) 203.

2)

N. E. Chayen et al.: J. Crystal Growth 171 (1997) 219.

3)

F. Otálora et al.: Acta Cryst. D57 (2001) 412.

4)

B. R. Thomas et al.: J. Cryst. Growth 211 (2000) 149.

5)

S. Takahashi et al.: J Synchrotron Rad.. 20 (2013) 968.

6)

H. Tanaka et al.: Ann. N.Y. Acad. Sci. 1027 (2004) 10.

7)

H. Tanaka et al.: J. Synchrotron Rad. 20 (2013) 1003.

－16－

26H08
ISS きぼう船内実験室利用テーマ「Soret-Facet」の運用状況○鈴木進補，橋本栄尭，長田拓真，森雄飛（早大），稲富裕光（ISAS），正木匡彦（芝浦工大），
渡邉匡人，水野章敏（学習院大），上野一郎（東理大），山根岳志（富山大），伊丹俊夫（北大），
中村裕広，勝田真登, 伊藤裕一，大熊隼人（JAXA），島岡太郎（JSF），曽根武彦（JAMSS）

Current status of “Soret-Facet” experiments aboard the ISS-JEM○S.Suzuki, Y.Hashimoto, T.Osada, Y.Mori (Waseda univ.), Y.Inatomi (ISAS), T.Masaki (Shibaura Inst. Tech.),M.Watanabe, A.Mizuno (Gakushuin Univ.), I.Ueno (Tokyo Univ. Sci.), T.Yamane (Toyama Univ.), T.Itami(Hokkaido Univ.), Y,Nakamura, M.Katsuta, Y.Ito, H.Ohkuma (JAXA), T.Shimaoka (JSF), T.Sone (JAMSS)
1. Introduction
Accurate data and basic knowledge of Soret coefficient ST arenecessary for the discussion on the process where temperature
gradient exists, such as crystal growth, solidification and so on.
We started the experiments “Soret-Facet”1) on July 2, 2014 toobtain accurate data of ST under microgravity conditions in theJapanese Experiment Module (JEM, Kibo) in the International
Space Station (ISS). The concentration and temperature changes
were measured in a solution under a temperature gradient using
two-wavelength Mach-Zehnder interferometer. The almost halfof the planned experiments were completed. We report theoverview and current status of the experiments in ISS/JEM.

temperature and concentration gradients in the stable state using
the moving distance. The setting temperature gradient wasvaried in the range between 0.4 and 2 K/mm, and the setting
temperature was varied in the range between 30 and 55 °C,
including supercooled liquid temperature region.
(d) Diffusion: After the procedure of a “Liquid Soret”
experiment, the temperature of the colder side was heated sothat the temperature should be homogeneous in the solution.
The moving distance of the fringes was measured during thetransient phase from the state with a temperature gradient to thestate with homogeneous temperature distribution.

3. Current Status and Trouble Shootings
2. Overview of the Experiments
The FACET-cells and two-wavelength Mach-Zehnderinterferometer in the Solution Crystallization Observation
Facility (SCOF) were used. There were two FACET-cells (Cell 1
and 2). The FACET-cells made of quartz glass were filled with asolution of Salol and tert-butyl alcohol. The nominal
concentration of the tert-butyl alcohol was 3 mol% (Cell 1) and6 mol% (Cell 2). Only the experiments of Cell 1 were performed
until September 2014. The apparatus and the solution specimen
were identical to those used in the experiments “FACET”, whichwere former ISS/JEM experiments for observation of crystal
growth. Therefore, the “Soret-Facet” experiments were able tobe performed without launching apparatus and specimen.
The FACET-cell (interior dimensions 16Lx4.8Wx1T mm3) was
sandwiched with two Peltier devices for controlling thetemperature. Laser beams (=532 and 780 nm) were applied tothe solution in the Mach-Zehnder interferometer. Interference
fringes were recorded during the experiments. The change anddistribution of temperature and concentration were calculated
from the moving distances of the interference fringes generated
by each laser beam. The shift of the fringes generated by thethermal expansion of the glass cell was canceled by the moving
distance of the fringes of the cell wall2).
The following experiments were performed by varying thetemperature programs.
(a) Melting Point: The temperature was controlled so as to set
the solid-liquid interface in the middle position between two
thermo-couples. This was done to estimate the concentration oftert-butyl alcohol, which was set before the launch and might
have changed during long time proceeded.
(b) Solid/Liquid Soret: The temperature distribution was set sothat the solution is solid in the colder side and liquid in thehotter side to discuss the Soret effect in a solid-liquid coexisting
system.
(c) Liquid Soret: The specimen was melted completely. Then atemperature gradient was set by lowering the temperature of one
side. The moving distance of the interference fringes wasmeasured during the temperature and concentration change.
The values of ST were obtained through calculation of the

All planed experiments of using “Cell 1” were performed in
Kibo. Several unexpected problem arose during theseexperiments. The status and solution are as follows.
(1) Resolution of fringes: The FACET-cell allowed only anarrow cell wall to observe for the cancelation of the thermal
expansion of the glass cell. Therefore, lateral interference
fringes (aligned vertically to the temperature gradient) wereapplied. Before the g experiments, it was confirmed that thelateral fringes provide the almost same ST values as parallel
fringes (aligned parallel to the temperature gradient), whichhave been used in 1g experiments.
(2) Hopping of interference fringes: Sudden hopping ofinterference fringes was found during experiments. As the
hopping took place at the same time also in the glass cell, it was
confirmed that the effect can be eliminated by cancelation
procedure of thermal expansion of the glass cell.
(3) Gas bubbles: Since several gas bubbles were found in thesolution especially in the solid/liquid Soret experiments, theobservation window was set at a position away from the gas
bubble. The effect of the bubble on the measurement is
considered not to be significant, because there was no clear
distortion of fringes around the gas bubble.
(4) Data loss: Movie images were disturbed by block noises
possibly caused by single event of IPU (Image Processing Unit)
in an experiment run. Two experiments of Liquid Soret were
either aborted or performed with data loss due to a failure of
Microgravity Measurement Apparatus (MMA). Another run forthese experiments was performed without data loss later.
All of movie data of the planned experiments were acquiredand currently under analysis.
Acknowledgments
We would like to gratefully thank the members of JAXA Flight
Control Team (JFCT) and FISICS, and the crew members of ISS
Expedition 40 for operation of the experiments.
References
1) S. Suzuki, et al., JASMAC27Abstructs (2013) 30.
2) Y. Mori, et al., Transactions of the JSASS, in press.

－17－

26A01「きぼう」を利用した液柱マランゴニ対流実験○松本聡（宇宙航空研究開発機構）

Overview of Experiment on Marangoni Convection in Liquid Bridge
using Japanese Experiment Module KIBO
○Satoshi MATSUMOTO (JAXA)

1. Introduction
Instability problems in fluid dynamics is a research area
where is being carried out actively. Fluid behavior sometimes
shows a very interesting phenomenon because of its strong
nonlinearity. Therefore, studying the instability problem mightadvance theoretical and mathematical science as well as fluid
dynamics as to progress the concept of chaos.
Marangoni flow is categorized in the natural convection sameas buoyancy convection caused by density difference. A traitof Marangoni convection is a surface-tension-driven flow which
driving force is localized at the only surface. Of cause, theflow instability occurs in Marangoni convection like ahydrodynamics or hydrothermal instability1).
Numerous studies have been carried out to make clear the
instability in Marangoni convection. Two types of configuration
were mainly focused, one was annular pool, other liquid bridge(cylindrical liquid column). The liquid bridge configuration
simulates the floating-zone method for crystal growth such as
semiconductor and oxide materials.
The final goal of JAXA Marangoni project is to fully
understand Marangoni convection occurred in wide range of
Prandtl number (Pr) fluid. For low and moderate Pr fluid,
ground-based studies are performed2-4).
For high Pr fluid, a liquid bridge of silicone oil is formed into
a pair of supporting solid disks. The convection is induced by
imposing the temperature difference between disks, one end
heating and other end cooling. Due to the convective
instability, flow transits from laminar to oscillatory, chaos, andturbulence flows one by ones as the driving force increases.
We observe the flow and temperature fields in each stage andinvestigate the flow transition conditions and processes.
Overview of Marangoni experiment onboard the ISS is
described in this paper.

implements space experiment on Marangoni convection withhigh Prandtl number. There are four experiments. The firstexperiment which principal investigator is Prof. Kawamura inTokyo University of Science had started in 2008. After five
years at present, eight series of experiments are completed and aplenty of fruitful results are obtained.
Fundamental questions regarding to Marangoni Convection
are the mechanism of oscillatory flow onset and flow transition
process. Four space experiments are implemented to solve
above question utilized long durational microgravity condition.
Marangoni space experiment is performed using Fluid
Physics Experiment Facility on Ryutai Rack in KIBO.
Silicone oil is employed as a working fluid.

3. Perspectives
As expected, the measured critical temperature difference Tc
for the more viscous liquid is substantially higher than that for
the less viscous one. Some of the experimental results are ingood agreement with each other, while others show the similar
patterns but are distinctly offset due, perhaps, to different fluid
viscosity and the relative size of the liquid bridges5,6).

will perform Marangoni experiments in KIBO until 2017.
Through a series of the experiments, we will be able tosystematically understand convective instability of Marangoni
convection and make clear the universality and differences
among

convection

such

as

unstableRayleigh-Bénard

convection or Taylor-Couette vortex flow.

References
1)
2)
3)

2. Space experiment
One of the major advantages of the International Space
Station (ISS) includes the long durational and high quality
microgravity condition. A lot of experiments are carrying out
utilizing such advantage. In fluid science field, Marangoni
convection (thermocapillary convection) induced in half-zone
liquid bridge have been observing both on the ground and on
board the ISS. Japan Aerospace Exploration Agency (JAXA)

JAXA

4)
5)
6)

－18－

S. Chandrasekhar: Hydrodynamic and Hydromagnetic Stability,
Oxford University Press (1961)
K. Li, N. Imaishi, C.J. Jing, S. Yoda: J. Crystal Growth, 370,
(2007) 155
S. Matsumoto, H. Hayashida, H. Natsui, S. Yoda, N. Imaishi:
Thermal Sci. and Eng., 12 (2004) 21
S. Simic-Stefani, M. Kawaji, S. Yoda: Int. J. Heat Mass Transfer,
49 (2006) 3167
H. Kawamura K. Nishino, S. Matsumoto, I. Ueno: J. Heat
Transfer, 134 (2012) 031005
S. Matsumoto, K. Nishino, I. Ueno, T. Yano, H. Kawamura: Int. J.
Microgravity Sci., 31 Suppl. (2014) S51

高プラントル数長液柱において表面張力流と逆向きに伝播する渦構造○矢野大志，西野耕一（横浜国立大学），上野一郎（東京理科大学），松本聡（JAXA）

Traveling of Vortical Structure in the Direction Opposite to the Thermocapillary Flow in HighPrandtl Number Long Liquid Bridge○Taishi YANO, Koichi NISHINO (Yokohama National Univ.), Ichiro UENO (Tokyo Univ. of Science),
Satoshi MATSUMOTO (JAXA)

1. Introduction
The instability of thermocapillary convection in an infinite
liquid bridge (LB) was investigated by Xu and Davis 1) bymeans of linear stability analysis (LSA) assuming thethermocapillary flow from the hot side toward the cold side near
the surface and its opposing return flow near the central axis.
Their result shows the neutral stability curves of m=0 and 1,
where m denotes the azimuthal wave number. Their traveling
directions of hydrothermal waves (HTWs) are opposite to(counter-flow direction) and same as (co-flow direction) thethermocapillary flow for m=0 and 1, respectively. Afterwards,
Ryzhkov 2) revisited the LSA for the same geometry as Xu andDavis. He found a new branch of neutral stability mode of m=1,
where HTWs are traveling in the counter-flow direction.
The experimental study in high AR (≥1.0) LBs of cylindricalshape is only possible under the reduced gravity condition,
where AR is the relative length H/D (Fig. 1). Schwabe 3) studied
HTWs in a LB of AR=2.50 under microgravity (µg) in sounding
rocket. His observed HTWs are traveling in the counter-flow
direction. In the recent µg experiments on the International
Space Station (ISS), the traveling of HTWs in the co-flow
direction are reported 4, 5), where the results contrasted with thetraveling direction of Schwabe. Possible reason of thiscontradiction is twofold: (1) large heat loss from the liquidsurface in the experiment in sounding rocket and (2)considerably higher Ma than Mac in the experiment on ISS,
where Ma is the Marangoni number and Mac is its critical value
for the onset of instability.
The present study is focusing our interest on the instability

Fig. 1and the flow structure of thermocapillary convection in long
LBs of high Prandtl number (Pr) fluid at conditions near the
onset of unsteady state, where the results were obtained underµg experiment on ISS.

2. Experiment
All the experiments have been conducted in the Fluid Physics
Experiment Facility (FPEF) on ISS 4). The geometry of ourinterest is a half-zone LB suspended between the cooled
aluminum disk and the heated sapphire disk (Fig. 1). The
temperature difference between those disks ∆T (=TH−TC) is thedriving force of thermocapillary convection. Silicone oil withthe kinematic viscosity of 5cSt (Pr=67) was used as the working
fluid. The relative liquid volume VR (=V/V0) was kept almost
constant at 0.95 to prevent the liquid leakage from the edge ofdisks (Fig. 1).
Three CCD cameras observe the flow field inside the LB
through the transparent sapphire disk from different viewing
angles. Captured images are used to reveal the time-dependent
flow structure by means of three-dimensional particle tracking
velocimetry (3-D PTV). The new particle tracking algorithm isdeveloped here and it can help us to achieve better results thanthe previous 3-D PTV results 5).

Fig. 2 Plot of Mac and F as a function of AR for Pr=67

Geometry of a half-zone liquid bridge－19－

Fig. 3Result of 3-D PTV for AR=1.25 and Ma≈Mac.
Fig. 4

Result of 3-D PTV for AR=1.50 and Ma≈Mac.

3. Results and Discussion
Figure 2 shows the plot of (a) Mac and (b) dimensionlessoscillation frequency F as a function of AR. Here, the respective
definitions of those parameters are shown as follows:
Mαc =

F=

σ T ∆Tc H
ρν α
H2

a Mac

(1)
(2)

f

where α is the thermal diffusivity, ν

the representative valueof the kinematic viscosity , ρ the density, σT the temperature4)

coefficient of surface tension, ∆Tc the critical ∆T for the onset of
unsteady flow and f the oscillation frequency. Note that theoriginal data of Mac and F can be found in the literature 4). The
present Mac exhibits local maxima at AR≈0.9 and 1.25. At thislatter AR, the present F shows a change of critical branch and it
is suggesting that there is other instability mode for long LB. In
this study, the branches for short liquid bridges (i.e., AR≤1.25)
and long liquid bridges (i.e., AR>1.25) are referred to as branch
A and branch B, respectively 6).
In long liquid bridges, the surface temperature fluctuationnear the critical condition is so small that the present
measurement apparatuses cannot provide a sufficienttemperature resolution to observe HTWs. For this reason, theinstability of thermocapillary convection is approached byvelocity field measured with 3-D PTV. Time series of particle
trajectories on the radial/axial-plane at conditions near the onset(i.e., AR=1.25-1.50 in the present condition) and such change ofthe instability mode is the reason of the jump of oscillation
frequency shown in Fig. 2(b). As reviewed by Yano et al., 5, 6)
the traveling of VSs is associated with HTWs, thus suggesting
the possibility of the traveling of HTWs in the counter-flow
direction at conditions near the branch B. Detailed results of thetraveling of VSs and HTWs can be found in other paper writtenby authors. 6)

4. Conclusions
This paper reports the experimental results on the instability
and associated vortical structures (VSs) of thermocapillary
convection in long liquid bridges of high Prandtl number fluid(Pr=67). The flow field is measured by using three-dimensional
particle tracking velocimetry (3-D PTV). The traveling of VSs is
recognized after the transition to the unsteady state and its
traveling directions for AR=1.25 and 1.50 are same as (from hot
to cold) and opposite to (from cold to hot) the thermocapillary
flow, respectively.

Acknowledgements
This study was financially supported by Japan Society for the
Promotion of Science (JSPS) KAKENHI (Grant-in-Aid for
Scientific Research (B), 21360101 and 24360078, and Grandin-Aid for JSPS Fellow, 13J02728).

Referencesof instability (i.e., Ma≈Mac) for AR=1.25 and 1.50 are shown in
Figs. 3 and 4, respectively. Note that the phase superposed
particle trajectories over several oscillation periods are applied
to these results. Figure 3 shows the presence of vorticalstructures (VSs) near the liquid surface and they are traveling in
the co-flow direction (from upper to lower). On the other hand,
the traveling direction of VSs in Fig. 4 is counter-flow direction.
It is important to mention here that the corresponding F for
AR=1.25 is on branch A and that for AR=1.50 is on branch B. It
follows from this result that the instability mode ofthermocapillary convection in long LB is changed at certain AR

1)

J-J. Xu and S. H. Davis: Phys. Fluids, 27 (1984) 1102.

2)

I. I. Ryzhkov: Phys. Fluids, 23 (2011) 082103.

3)

D. Schwabe: Phys. Fluids, 17 (2005) 112104.

4)

H. Kawamura, K. Nishino, S. Matsumoto and I. Ueno: ASME, J.
Heat Transfer, 134 (2012) 031005.

5)

T. Yano, K. Nishino, H. Kawamura, I. Ueno, S. Matsumoto, M.
Ohnishi and M. Sakurai: Exp. Fluids, 53 (2012) 9.

6)

－20－

T. Yano, K. Nishino, H. Kawamura, I. Ueno and S. Matsumoto:submitted to Phys. Fluids.

26A03環状プール内の定常表面張力対流の安定限界に及ぼす表面熱伝達の影響〇今石宣之（九州大学），M. Ermakov（Inst. Prob. Mechanics），石万元（重慶大学）

Effect of Surface Heat Transfer on the Stability Limit of Thermocapillary Flowin Annular Pool
N. IMAISHI (Kyushu Univ.), M. ERMAKOV (Inst. Prob. Mechanics), W.Y. SHI (Chongqing Univ.)

1. Introduction

140

150

120
Ren

Pr=6.7, 0G
d=1.0mm, Bib=0: 





100

Pr=6.70, 0G, d=1mm
Bit=0.050, Bib=0
Min. Re n for HTW2 (Bi t=0, m=59).Re c for Bi t=0 (HTW1, m c=28)

Rec, Ren

Axisymmetric steady two dimensional thermocapillary flowin annular pools (depth d=1-20mm, radius of the outer wall
Ro=40mm, radius of the inner wall Ri=20mm) driven by atemperature gradient in the radial direction and buoyancy
becomes unstable and the hydrothermal waves1) and otherthree dimensional flows set on when the temperature difference
between the walls exceeds a certain threshold value. However,instability mechanism and flow modes in pools of finite extent
are still not well understood. In the present work, our LSA2)model is extended to evaluate the effects of thermal boundary
conditions on the stability of buoyant-thermocapillary flow inannular pool.





HTW2

80
50

HTW1

60

HTW1
HTW2



0

0.02

0.04
Bit

0.06

-2

0.08

-1
0
1
A=(TA - Ti)/(To - Ti)

2

Fig. 1 Effects of BiT and A on the neutral condition (d=1mm).
HTW2: d=5mm, 0G, Bi b=0
0.5
 A=

5
=0.7

A

300

mn=9

300

 A=0

25

 A=0.

Pr=6.70, 0G, d=5mm
Bit=0.25, Bi b=0
HTW2

400

A=1.0

Rec

Rec

400

mc=4
Re c for adiabatic surface (HTW2, m c=9)

200

200

mc=11

mc=10

100

2. LSA Model

1000

LSA model assumes a thin solid layer (thickness db andthermal conductivity kb) between the pool bottom and a baseplate which has a steady conductive temperature distribution in
the radial direction. Thermal conductance between the baseplate and the liquid pool is expressed by the Biot number
Bib=kbd/kldb. In this work, we assume Bib=0, i.e., the pool
bottom is adiabatic. BiT=hd/kl is used for the thermal
conductance between the liquid surface and the ambient gas at a
uniform temperature Ta. The details and calculation method
were described at JASMAC-27.

Fig. 2 Effects of BiT and A on the neutral condition (d=5mm).

1

2

3

4

0
-2

5

-1
0
A=(TA - Ti)/(To - Ti)

Bit

Pr=6.7, 0G, h=5.0 Wm-2K-1
R=20mm

5

Rec

dotted line : Bi t=0
A=0

10

Black line : HTW1
Red line : HTW2
dotted line : Bi t=010
A=1.0Black line : HTW1
Red line : HTW2

Tc [K]

10

3

1

1

A=1.00.5

2

Pr=6.7, 0G, h=5Wm-2K-1
R=20mm

10

0

10

0.1
0.5

1

1

5
d [mm]

d [mm]

A=0

10

Fig. 3 Rec and Tc as a function of d and A (Pr=6.7, 0G).
2200

3.1 Effect of A and Bit on 3-D flows of medium Pr fluid.
As was reported at the JASMAC-27, small heat loss from theliquid surface reduces Rec   T Tc ( Ro  Ri ) /  for HTW1 butlarger heat loss increases Rec significantly for a shallow pool of
medium Pr fluid (Pr=6.7, d=1.0mm, Bib=0, 0G). On the other
hand, heat gain from the gas phase always stabilizes the steadyaxisymmetric flow against HTW1. It should be noted that BiTand A=(Ta  Tc ) / (Th  Tc ) lead to the adverse effects on HTW2.
The effect of Bit and A on stability limits are shown in Fig.1
and Fig.2 for shallow (d=1.0mm) and medium (d=5mm) pools,
respectively. The critical Reynolds number (Rec) and criticalRec

3. Result and discussion

Effect of A on Re c
Pr=6.8425, Bi b=0. Bi t=0.20, d=20mm, 0G

0.8

Tc [oC]

2000
1800
1600

Pr=6.84,
0G, d=20mmo
Tc=20 C, Bib=0

0.6
0.4

1400

Bi t=2.0(h=10 W/m 2K)
Bi t=0.20(h=1.0 W/m 2K)

Rec=1368.686 Bit=Bi b=0

dotted line: Tc for Bi t=Bi b=0

1200
-10

-5
A=(Ta-Tc)/Tc

0

0.2
16

17

18
19
Ta [oC]

20

21

Fig. 4 Effects of A on the critical conditions (Pr=6.84, d=20mm).

the azimuthal wave number mc and oscillation frequency fc.
In shallow pools, HTW2 becomes the most dangerous mode
under large heat loss. In deeper pools, HTW2 is the mostdangerous mode and large heat gain tends to increase Tc andtemperature difference (Tc) depends on pool depth and A as

reduce the wave number. Reduction of mc by heat gain becomesmost significant in pools with medium depth. LSA results forshown in Fig. 3 for Pr=6.7 under 0G. These results show thePr=6.84 predicts that Rec (Tc) values are about twice of thosesignificant effects of the surface heat transfer on Tc as well asreported by Sim et al3). Fig.4-b suggests that the ambient－21－

temperature Ta and heat transfer coefficient h causes significant(OSC3) appears at Bit>0.016.

change of Tc, especially when Ta is higher than the outer wall.

Effects of A on the neutral stability conditions for d=1mm,

However, high heating destabilizes the basic flow at Re>3400.
Thus LSA can't provide quantitative explanation for the spaceexperiment results of MAGIA3) ( Rec  7000 for d=20 mm).
In case of buoyant-thermocapillary flow under 1G condition,
the stability diagram becomes more complex because a flowmode change from HTW1 to HTW2 occurs at small depth and
3D steady flow occurs in deeper pools. For a case of d=1mm,
the stability diagram seems similar to that shown in Fig.1. Effect

1G, Bib=0 and Bit=0.003 (h=192W/m2K) is shown in Fig.7.
Appearance of 3DSF3 and OSC3 correspond to the large
deformation of the basic flow field from that in the pool with anadiabatic surface (Bit=0) caused by interfacial heat transfer.

3DSF

A=1.0A=0.5
A=0.25
A=0

Re

2000

HTW2

A=1.0A=0.5
A=0.25
A=0

Re

800
600
-2

1
Bit

3DSF2

3DSF3
OSC1
OSC2

-1

In case of deeper pools, the neutral stability branches of 3DSF
locate far above that of oscillatory flow modes and the effects ofthe surface heat transfer is less significant than for shallow pools.
4. Conclusion
Linear stability analyses foe annular pools revealed thedetailed effects of the thermal boundary condition on the poolsurface for medium and low Pr fluids as follows.
1) In case of medium Pr fluids, surface heat loss stabilizes thebasic flow against HTW1 but destabilizes against HTW2.
Heat gain from the ambient gas phase works in the opposite
way. These effects cause disappearance of HTW1 in shallow
pools under large heat loss conditions.
2) In case of medium and large depth pools of medium Pr
fluids, small heat loss destabilizes against HTW2 but larger
heat loss stabilizes and increases mc.. Heat gain largely
stabilizes the basic flow and reduces mc.
3) Large heat loss from the surface gives small effects on the
3DSF in medium Pr pool, on the other hand, destabilizes
against HTW2. Therefore, large heat loss causes change ofcritical flow mode from 3DSF to HTW2 in pools of medium
depth under 1G. .
4). Neutral stability curves for low Pr liquid’s pool show strong

2

Fig.5 Effects of Bit and A on the critical conditions
an annular pool against of d=5mm, Pr=6.7 under 1G..

in

3.2 Effect of A and Bit on 3-D flows of a low Pr fluid.
In shallow pools of low Pr fluids, the Marangoni effect driven
by the radial temperature gradient induces a strong basic flow
and this basic flow becomes unstable against 3D perturbations
and 3-D oscillatory flows OSC1 or OSC2 and 3D steady flow
3DSF1 set on at a certain threshold Reynolds number.
Fig.6 shows the neutral stability curves for each flow mode asa function of Bit for Pr=0.011, d=1.0mm under 1G and A=0. It
should be noted that this figure covers a very wide range of hvalues since Bit=0.001 corresponds to h=64 W/m2K.
In the basic flow placed in an environment of A=0, radial
temperature gradient near the outer pool increases at Bit>0.001,
and the most dangerous 3-D flow mode changes from OSC1 to
OSC2. When Bit exceeds 0.00488 at 1G a 3D steady flow
(3DSF3) becomes the most dangerous mode and a flow mode
Pr=0.011, 1G, A=0
d=1.0mm

3DSF1

0
1
2
A
Fig.7 Effect of A on the neutral stability curves.

1000
0

OSC3

1000

Fig.5 indicates that 3DSF is the most dangerous mode for
adiabatic pool, heat gain and small heat loss cases. However,under large surface heat loss the basic flow becomes unstable atsmaller Re value against HTW2 .
d=5mm, 1G, Pr=6.70, Bib=0

dotted lines: Bi t=0

1200

of Bit and A on the stability of a pool of d=5mm shown in

3000

Pr=0.011, 1G, d=1mm
Bit=0.003, Bib=0(h==192 W/m2K)

1400

and complex Bit and A dependencies. Under large surface
heat fluxes, new flow modes, such as 3DSF2 and OSC3, set
on. These flow modes correspond to big change of the basic
flow field caused by the surface heat flux.

3DSF4

2000

Re

References
OSC2

1)

M.K. Smith and S.H. Davis: J. Fluid Mech., 132 (1983) 119.

2)

WY Shi, M. Ermakov and N. Imaishi: J. Crystal Growth, 294(2006) 474.

3)

B.C. Sim, A. Zebib and D. Schwabe, J. Fluid Mech., 491(2003)
259.

3DSF3
3DSF2

1000

3DSF1

OSC3

OSC1

10-4

10-3

Bit

10-2

10-1

Fig.6 Effect of Bit on the neutral stability curves for Pr=0.011 d=1.0mm,

–

－22－

26A04
容器内動的濡れ挙動のＣＦＤ解析○今井良二（室工大）

CFD Analysis for Dynamic Wetting Behavior in a Container○Ryoji IMAI (Muroran Institute of Technology )1. Introduction
Fluid behavior in microgravity (g) is different from inground gravity since surface tension, viscous force, and wetting
are dominant in g condition.

In propellant tank for artificial

satellite and future on-orbit spacecraft, sloshing due todisturbance and settling behavior by change of acceleration haveto be understood for design of propellant supply system andattitude control system.
In past years, many researches for fluid behavior in tank havebeen done, however, in general, dynamic contact angle anddynamic wetting; main parameters which characterize g fluid
behaviors, have been treated empirically. On the other hand,
there are large number of researches for dynamic wetting inground gravity 1). However, dynamic wetting phenomena havenot been fully understood since there are difficulties in treatingfrom micro to macroscopic physics. In addition of this, thesestudies targeted small scale objects such as capillary tube anddroplet, therefore there are less studies treating relation between

assumed to be same as ones used in Kato’s paper 4). Contactline velocity was obtained by multiplying velocity vector on
numerical cell neighbored on sidewall and unit gradient vectorof VOF.
Table 1 shows fluids and these properties. Static contact
angle was assumed to be 0 degree. In this calculation,
diameter and height of cylindrical container was 0.01m and
0.03m respectively.
Figure1 shows snapshot of liquid behavior, that is volume
ratio of liquid. It is found that liquid behavior depends on
formula for dynamic contact angle; rising speed along side wallis largest in Cox’s formula, and in Kato’s formula, thin liquidfilm was not formed on the upper area of side wall.
Table 1

Thermal properties

Liquid phase

Silicon oil

Density

818 kg/m3

Viscosity

8.18x10-4 Pas

dynamic wetting and macroscopic fluid behavior under g

Gas phaseAir

condition in which dynamic wetting is dominant even in large
scale object.
Our final target is to understand how dynamic wetting affectDensity

1.225 kg/m3

Viscosity

1.7895x10-4 Pas

macroscopic and large scale fluid behavior in g condition.

3. Conclusion

This paper describes results of CFD analyses which investigate
the effect of theoretical and empirical equations for dynamic

Numerical calculation was made to investigate the influencesof theoretical and empirical formulae of dynamic contact angle
on fluid behaviors in cylindrical container. As a next step, we
will conduct short term microgravity experiment and construct atheoretical model to realize effect of dynamic wetting

contact angle on fluid behaviors in g condition.

2. Numerical calculation of fluid behaviors incylindrical container considering dynamic wetting

phenomena on macroscopic fluid behavior in g condition.

Fluid behaviors without gravitational force driven by
dynamic wetting in cylindrical container were analyzed bycommercial CFD code ANSYS FLUENT. VOF (Volume of
Fluid) method was employed to calculate two phase flow, andgeometric reconstruction scheme was applied as an interface
reconstruction algorithm. Surface tension was considered in
momentum equations by CSF (Continuum Surface Force)
method. Dynamic contact angle was applied as a boundary
condition on cylindrical wall. There are many equations for
dynamic contact angle which has dependency of contact line
velocity by theoretical and empirical approach. Cox’s 2) and
Kato’s 3) formulae were used to provide dynamic contact angle,
and values of empirical coefficients in these formulae wereReferences
1)T. D. Blake,: J. of Colloid and Interface Science, 299(2006) 1.

2)

R. Cox: J. of Fluid Mechanics, 168(1986) 169.

3)

K. Kato, T. Wakimoto, S. Nitta: J. Jap. Soc. Exp. Mech. 10(2010)
s62.

4)

K. Kato, T. Wakimoto, Y. Yamamoto, T. Ito: Experimental Thermaland Fluid Science Available online (2014).

－23－

0.0 sec

0.0 sec

0.0 sec

0.1 sec

0.1 sec

0.1 sec

0.35 sec

0.35 sec

0.35sec

1.0 sec(1) Dynamic contact angle is 0 degree(constant)

1.0 sec(2) Cox’s formula

1.0 sec2)

Fig.1 Snap shot of liquid behavior(Contour of volume fraction of liquid)－24－(3) Kato’s formula 3)

26A05

月レゴリスシミュラントの溶融塩化学○後藤琢也,

坂中佳秀（同志社大学），福中康博（早稲田大），
M.V.クマール，石川毅彦 （JAXA）

Utilization of Lunar Resource by using Molten Fluoride Technology
Takuya GOTO, Yoshihide SAKANAKA (Doshisha Univ.), Yasuhiro FUKUNAKA(Waseda Univ.),
M.V. KUMAR, Masahiro TAKAYANAGI(JAXA)

1. Introduction
In-situ resource utilization for space activity is very important
for realizing the construction of lunar base. Electrochemical
extraction of silicon from regolith is an attractive method fromthe point of view of space utilization, because the method gives
not only silicon for solar cell but also oxygen for human activity.
Development of a new oxygen evolution electrode in molten
fluorides is thus required, since molten fluorides are expected to
be an electrolyte for electrochemical reduction process of lunar
regolith. An inert electrode available for oxygen evolution in
molten fluorides at elevating temperatures has thus been
investigated by many researchers. Considering sustainability ofthe processes, the anode composing of nontoxic and abundantmaterials is preferential. In this study, FeAl2O4, hercynite has
been selected and attempted to be prepared by a conventional
ceramic method. Structure, morphology and resistivity of theobtained sample at room temperature were studied. Oxygen
evolution behavior was also investigated in a LiF-KF-NaF melt
to test the possibility of a new anode.

3. Results and discussion
The X-ray diffraction patterns of calcinated powder andsintered hercynite ceramics are shown in Fig. 1. Fig. 1(a) is the
XRD patterns of hercynite powder calcinated at 1173K for 6h in
the N2 - 1 vol% H2 atmosphere, and (b) is the XRD patterns ofhercynite ceramics sintered at 1623K for 6h N2 – 0.1 vol% H2
atmosphere. Each observed peaks were identified as FeAl2O4 .
And the relative density of obtained hercyite ceramics was
99.8% measured by Archimedes’method.
The electrode behaviors of oxide ions in a LiF-KF-NaF meltwith FeAl2O4 and SiC electrodes were investigated by cyclic
voltammetry. On the anodic sweep, anodic current was observedwith shown as following reaction.
O2- → 1/2O2 + 2eIn order to test the stability of FeAl2O4 and SiC electrodes,
galvanostatics electrolysis at 50mA was carried out for 1h in a
molten LiF-NaF-KF containing SiO2 at 773K. The result isshown in Fig.2 and the availabibility as inert anode of FeAl2O4
and SiC electrodes was confirmed, because steady current andsteady potential were observed during electrolysis in both cases.

2. Experimental
The regent grade raw materials of γ-Al2O3 and α-Fe2O3 inmolar ratio of 2.0 were mixed with alcohol and calcined at 1123
K under a N2–10vol% H2 flow for 2 h to form FeAl2O4 powder.
The obtained sample was compacted by CIP of 200 MPa to
obtain a square-pole shape. The compact was then sintered at1723 K for 8h in a N2 - 0.1 vol% H2 gas flow. The samples werecharacterized by an x-ray diffraction. A scanning electron
spectroscopy and four contact conductivity measurement was
carried out at room temperature. Electrochemical measurement
in a LiF-NaF-KF eutectic was carried out by a three electrodesystem under argon atmosphere. Lithium oxide (Li2O) was usedas the oxide ion source. The working electrode was a hercynite
electrode and the counter electrode was a glassy carbon rod. The
reference electrode was an Ag+/Ag electrode and the potential ofthis reference electrode was calibrated with reference todeposition potential of potassium1).

Fig 1. XRD pattern of FeAl2O4 : (a) calcinated powder; (b)hercynite ceramic.

Fig 2. Potential of working electrode (FeAl2O4) and counterelectrode (Al plate) during galvanostatics electrolysis.

－25－

26A06電磁浮遊融液からの一方向凝固による Fe リッチβ
リッチβ -FeSi2 の組織と熱電特性○永井秀明（産総研），山田高広（東北大）

Thermoelectric Properties and Morphology of Fe-rich β -FeSi2 Prepared by Unidirectional
Solidification from Electromagnetic Levitated melts○Hideaki NAGAI (AIST), Takahiro YAMADA (Tohoku Univ.)

1. Introduction
β-FeSi2 is known as one of the high temperaturethermoelectric materials. This material consists of Fe and Si,
and both elements exist enough in the earth. However, single
phase

β-FeSi2bulk

sampleshows

lowthermoelectricperformance because of high thermal conductivity andinsufficient electric conductivity. Our previous work hasrevealed that β-FeSi2 sample with aligned FeSi phase improved
the thermoelectric performance1).

In this way, the modificationof morphology of β-FeSi2 sample, such as introduction of
second layer with electrical conductive nature (FeSi) and themicropores etc., is one of the possibilities to improve thethermoelectric performance. In this study, we synthesized Ferich β-FeSi2 by solidification from electromagnetic levitated(EML) melts and the following annealing to control themorphology of the sample and evaluated the thermoelectric
properties.

2. Experimental
Starting Fe-Si compounds were prepared by arc-melting of
the constituent elements ([Fe+Co]:Si=35.3:64.7, Fe:Co=95:5 [inmole]). The arc-melted sample was cut into the suitable size.
This sample block was set on the unidirectional solidification
system using electromagnetic levitator, as shown in Fig.1. In
this system, the levitated sample was cooled by helium gas flow
(1L/min) and dropped on the cooling chill (BN, Si, Cu blocks,
and Cu block
Pyrometerwith Sn layer).
Sampletemperature
was measured
Working
Samplecoil
byopticalpyrometer from
Sample holder
Chillthe upper sidesof the system.
The obtained
samples wereanalyzed
by
XRD,
SEM
beforeandafter annealing
at 1073 K forAr

6h. The thermoelectric properties were evaluated by electricalconductivity and Seebeck coefficient after annealing.

3. Results and Discussion
All solidified sample were mixture of α-FeSi2 phase and FeSi
phase. Arc-melted sample had coarse FeSi phase with somealignment along cooling direction because of low cooling rate.
The microstructure of EML samples became fine, as shown in
Fig.2, because of higher cooling rate than that of arc-melted
sample, but the samples had less orientation of FeSi phase.
The samples solidified with BN and Cu cooling chill, and Si
chill from different melt temperature had similar microstructures.
Because the wettability between sample melt and cooling chill
was bad, the cooling rates of the melts were considered to be
similar. Our previous work reported that high cooling rate wasachieved by splat-solidification of FeSi2 melt on Cu chill blockwith Sn layer2), because of good contact between FeSi2 melt andcooling chill. When Cu block with Sn layer was used ascooling chill, the sample melt had good contact with coolingchill and higher cooling rate was obtained. Due to the higher
cooling rate, the sample had quite fine microstructure without
dendrite structure. This area thickness was about 200µm.
Some FeSi phase dendrite structure without orientation
appeared above the area, and the microstructure far from thecooling chill was similar to those solidified by other coolingchill because of decreasing the cooling rate. On the other hand,
the microstructure synthesized by unidirectional solidification inµg had rather coarse FeSi phase with alignment along cooling
direction.

He
Vacuum pumpFig.1 Unidirectional solidification system
by electromagnetic levitator－26－

After annealing, the area of FeSi phase decreased

and network of FeSi phase became poor. This tendency was
remarkable as microstructure of FeSi phase became fine, and the
FeSi phase in the EML samples was mostly dispersed in thematrix without orientation. Both arc-melted sample and EML

Acknowledgement
The study is partly supported by Cooperative Research
Program of “ Network Joint Research Center for Materials andDevices.”samples rarely had the mixture area of β-FeSi2 phase and Si
phase, which was created by decomposition of α-FeSi2.

References

Figure 3 shows the thermoelectric properties of Fe-rich βFeSi2 with different microstructure after annealing. EML
samples had lower conductivities than that of arc-melted sample
because of fine microstructure. On the other hand, theconductivity of the sample synthesized by unidirectional

1)

H.Nagai, D.Saito and T. Okutani: Abst. of 27th Jpn. Soc.
Microgravity Appl. Conf., Nov., 2013, 92.

2)

H.Nagai, Y.Nakata, M.Shibuya and T.Okutani: Jpn. J. Appl. Phys.,solidification in µg increased with temperature, and higher
conductivity was achieved at high temperature. Seebeckcoefficient of EML sample using Cu block with Sn layer was
lower than those of other samples. Because this sample still
remained fine microstructure after annealing, insufficient crystal
growth of β-FeSi2 phase was considered to decrease the value ofSeebeck coefficient.
As a result, the thermoelectricperformance of the sample with fine microstructure and poor
network of FeSi phase without orientation was lower than thoseof other sample.
Conductivity (S/cm)

800"
600"
400"
200"
0"
400""

600""

800""

1000""

1200""

Seebeck coefficient (µµ V/K)

Temperature (K)!80%%!100%%!120%%!140%%!160%%!180%%
400%%

600%%

800%%

1000%%

1200%%

Temperature (K)Power factor (W/K2m)

1.2E'03%(a)Arc-melted sample

1.0E'03%
8.0E'04%(b)EML sample (BN chill)

6.0E'04%(c)EML sample (Cu chill with Snlayer)

4.0E'04%
2.0E'04%
0.0E+00%400%%(d)Unidirectional solidification inµg (Cu chill)
600%%

800%%

1000%%

1200%%

Temperature (K)Fig.3 Thermoelectric properties of Fe-rich β-FeSi2
with different microstructure－27－

42 (2003) 1690.

26A07
JEM 与圧部および曝露部における微小重力環境○石川巨樹（株式会社エイ・イー・エス），伊藤剛，小仁所裕喜子（宇宙航空研究開発機構）

Microgravity Environment of JEM Pressurized Module and JEM Exposed Facility○Naoki ISHIKAWA (Advanced Engineering Services, Co., Ltd)Tsuyoshi ITO, Yukiko KONISHIO (Japan Aerospace Exploration Agency)

1. Introduction
Microgravity environment is one of the most favorable
characteristics for science experiment in the JapaneseExperiment Module (JEM). However, it is disturbed due tovibration caused by movement of crew members, onboard
equipment operations and docking event of visiting vehicle, etc.
JAXA has measured the disturbance in JEM Pressurized Module(JPM) using Microgravity Measurement Apparatus (MMA)
since 2008 and that on JEM Exposed Facility (JEF) using
Microgravity Measurement Equipment (MME) since 2013
because those data are necessary for planning experimentutilizing microgravity condition.
The disturbance data acquired by the MMA has been alreadyanalyzed and reported.1), 2) Furthermore, additional data recently
taken by the MME could provide more detailed microgravity
environment data to experiment users in the JEM.

2.2 Microgravity Measurement Equipment (MME)
There are three MMEs on the JEF with three measurementmode (Table 2). Each MME has acceleration sensors in three
directions as shown in Fig. 2.
Table 2

MME Specification
Sampling

Acceleration

Measurement
mode

Frequency
range [Hz]frequency

range [G]Low

0.01~10100

5x10-7 ~ 2x10-3

High

5.0~3002000

5x10-6 ~ 2x10-2

Extension

5.0~3002000

5x10-5 ~ 2x10-1[Hz]

2. Accelerometer Description
2.1 Microgravity Measurement Apparatus (MMA)
Three MMAs are located in experiment racks in the JPM andeach MMA has acceleration sensors in three directions as shownin Fig. 1 and Table 1. The maximum sampling frequency is1220Hz and the maximum cutoff frequency is 300Hz.

Fig. 2

MME Sensors Location and Direction

3. Analysis Result

Fig. 1
Table 1

ISS and JEM Direction

MMA Sensors Direction and Locations

Location

Direction
+X

+Y

+Z

Saibo Rack

OverheadStarboard

ForwardRyutai Rack

OverheadStarboard

Forward

Kobairo Rack

Overhead

Port

Aft

One-third octave band analysis results and spectrogram of
measurement data acquired by MMA on Ryutai Rack and
MME-S2 are shown in Fig. 3 thru Fig. 7. Those data had beenacquired for 15 hours (GMT18:00 - 09:00) without special gjitter event, such as docking of visiting vehicle. This time,sampling frequency and cutoff frequency of the MMA was
1220Hz and 300Hz. The MME had taken the data in low mode.
For forward direction and overhead direction, the MMEshows higher acceleration at around 0.2~0.9Hz compared to the
MMA, though no major difference is found for starboard
direction.
It is known that the ISS has a natural frequency at around－28－

PSD [Log(G^2/Hz)]

1×10-2Frequency [Hz]0.25~0.3Hz. It is considered that JEF is more affected be natural
vibration of the ISS than JPM because the JEF is attached at
port side of the JPM which is more distant from gravity centerof the ISS. Therefore, it is presumed that the acceleration datataken by the MME is affected by the natural frequency of theISS.

Acceleration [G]

1×10-3

1×10-4

1×10-5Time [hh:mm:ss] (GMT)
1×10-6

Fig. 6

Spectrogram (MMA on Ryutai Rack)

1×10-7

1×10-8
0.01

0.1

1

10

Frequency [Hz]NASA Requirement

MME-S2

1×10-2

1×10-3

Acceleration [G]

PSD [Log(G^2/Hz)]

One-third Octave band (ISS forward direction)
Frequency [Hz]Fig. 3

MMA on Ryutai Rack

1×10-4

1×10-5

1×10-6

1×10-7

1×10-80.01

Time [hh:mm:ss] (GMT)Fig. 70.1

1

NASA Requirement

Fig. 4

4. Conclusion

MMA on Ryutai Rack

MME-S2

One-third octave band (ISS starboard direction)

1×10-2

Acceleration [G]

1×10-3

1×10-4

1×10-5

1×10-6

1×10-7

1×10-8
0.01

0.1

1

10

Frequency [Hz]NASA Requirement

Fig. 5Spectrogram (MME-S2)

10Frequency [Hz]MMA on Ryutai Rack

MME-S2

One-third octave band (ISS overhead direction)

Microgravity environment data taken by both MMAs andMMEs for 15 hours a day without special g-jitter event has been
analyzed. The results show that the environment on the JEF isaffected by the natural frequency of the ISS, and it is different
from that in the JPM. In addition, it was found that the MMA on
Ryutai Rack and MME-S2 is respectively sensitive to thevibration at different frequency due to the structuralcharacteristics.
Studying microgravity environment in both the JPM and the
JEF is effective method to comprehensively understand JEM
microgravity environment. We will continue analyzing the JEM
microgravity environment with this method in order to achieve
good experiment results in low-disturbance microgravity
environment.

References
1)

M. Goto, K. Murakami, H. Ohkuma: J. Jpn. Soc. Microgravity
Appl, Vol.28 No.1 (2011) 8

2)

H. Ohkuma, K. Murakami, M. Goto: J. Jpn. Soc. Microgravity
Appl, Vol.28 No.1 (2011) 13－29－

26A08JEM 搭載微粒化観察装置の開発状況その２○大熊隼人，中村裕広，菊池政雄，伊藤裕一，柚木園諭（JAXA），梅村章（名産研），中神秀俊，
瀬良暁雄，古友大輔，小林涼華（千代田化工建設）

The Status of Development of Atomization Observation Equipment in JEM 2○Hayato OHKUMA, Yasuhiro NAKAMURA, Masao KIKUCHI, Yuichi ITO, Satoshi YUKIZONO (JAXA),
Akira UMEMURA (NISRI) , Hidetoshi NAKAGAMI, Akio SERA, Daisuke FURUTOMO, Ryoka KOBAYASHI(Chiyoda Co., Ltd)

1. Introduction
Liquid atomization is a very important to spray combustion.
However, atomization mechanism is poorly understood due tothe technical diffculty that the phenomenon ends with anextremely short period and tiny scale that it only can beinterpreted by high-speed camera technique. JAXA has newly
developed Atomization Observation Equipment (hereafterrefered as AOE) for space experiment in Kibo/ISS. The purposeof this experiment is validation of the new atomization concept
by observing the breakup behaviors of water jets in closeup. At
this experiment, water is injected from syringe. Then the wateris atomized after a period of time. We shoot the behavior withhigh-speed camera.
AOE will be attached to the Work Volume (hereafter refered
as WV) section of the Multi-purpose Small Payload Rack
(hereafter refered as MSPR) in Kibo.

Type A

2. Space experiment in JEM
We will observe the breakup behaviors of water jets undercontrol of water injection speed. The speed is changed infollowing three type.
The vertical axis in each graph is injection speed. And
horizontal axis is time.
On Type A, injection speed is continuously changed in order
to investigate atomization hysteresis. Type B is intermittent
injection type. We will compare the result of experiment Type A
and Type B. The water is injected at a constant rate on Type C.
We expect to acquire correlation function of breakup distance inthis type.

Type B

3. Overview of Equipment
AOE has mainly three functions. First function is speed
control of injection water. The second is acquiring the image ofwater jet with high speed camera. The last function ismeasurement of various data such as water speed andtemperature.

－30－

Type C
Fig. 1

Injection Speed TypeFig. 2

Atomization Observation Equipment

The function and specification of each component are as
follows.
[Enclosure]
Enclosure is a container in which water is injected. Side wall
has a transparent window for observation with high-speed
camera. Enclosure is made of aluminum alloy plate and thewindow is made of Polycarbonate.
[Specimen Container Drive]
Specimen Container Drive is a linear drive porter with linear
encoder, to drive the Specimen Container at the designatedspeed. The travel of the drive is about 260mm. Linear encoder
has an optical marker to precisely measure and control the
position of the drive.
[High Speed Camera]
High Speed Camera equipped with an electric zooming/focusinglens is to capture the high speed image of water injection. All
operations are executed automatically including the focusing
and zooming which is performed from the ground bytelecommandings.

[Monitoring Camera]
Monitoring Camera is a CCD Camera which acquires thegeneral image of the experiment.
[LED Light]
LED Light is an array of white LED chips. It is to illuminate thewater jet for image acquisition with High Speed Camera.
[Specimen Container]
Specimen Container is a cylindrical chamber made of plastic
that store water inside. 400ml of water is stored in one container.
[Drop Capture Part]
Drop Capture Part catches injected water. Inside of the part isconically shaped and lined with sponge-like absorbent. One
Drop Capture Part can hold up to 700ml of water capability.

4. Status of development
We have fabricated AOE’s Prototype Flight Model（PFM）
and finished the Proto Flight Test (PFT).
Currently we are acquiring ground experiment data. We willreport the result of ground experiment in the presentation

References
1)

A. Umemura, S. Kawanabe, S. Suzuki & J. Osaka, Phys. Rev. E,84(2010) 036309.

2)

A. Umemura, Phys. Rev. E, 83(2011) 046307.

－31－

26A09液滴群燃焼実験供試体フライトモデルの開発状況○菅 勇志，菊池 政雄，高柳 昌弘，水島 隆成（JAXA）

Dvelopment status of Group Combustion Experiment Module Flight Model
Yuji KAN, Masao KIKUCHI, Masahiro TAKAYANAGI, Takanari MIZUSHIMA (JAXA)

1. Outline
Elucidation of Flame Spread and Group Combustion
Excitation Mechanism of Randomly-distributed Droplet Clouds
is the objective of the “Group Combustion”, to be performed asa Japanese Experiment Module/KIBO second phase utilization.
“Group combustion” experiment is planned to employ theMulti-purpose Small Payload Rack (MSPR) and the Chamber
for Combustion Experiment (CCE) which were installed in
KIBO. We report the development status of GCEM Proto Flight
Model(PFM)

3. Development Status
3.1. Current Status
Production of GCEM PFM has been completed(see Fig 3, Fig
4, Fig 5). GCEM PFM passed Function Test, Vibration Test,
EMC Test, Fit Test, and more some Tests.
Group Combustion passed PSRP Phase 0/1/2/3 on last June andpassed the PQR last July.

2. Outline of the Experiment Module
Combustion Experiment Module is installed inside theChamber for Combustion Experiment (CCE) which is installedin Multipurpose Small Payload Rack(MSPR). CCE is one of thecomponents of the MSPR(see Fig. 1).

Fig. 3 GCEM FM

Fig. 1 Overview of the experiment MSPR/CCE
Fig. 4 Combustion VesselGroup Combustion Experiment Module (GCEM) is composedof Small Combustion Vessel, Fuel Supply Unit, Observation
Unit, Communication Control Unit, Gas Supply/Vent Plumbing
Unit, Gas bottle A Assy, and Filter(see Fig. 2).

Fig. 5 Gas Bottle A ASSY

Fig. 2 Overview of the GCEM

4. Schedule
GCEM PFM will launch by Orb-4 in April 2015. The
experiment on orbit will start after launch.
Before launch, Gas Bottle A ASSY will be filled Gas(O2+N2) atthe Wallops Flight Facility.

－32－

26A10
酸素製造装置の軌道上実証○桜井 誠人，島 明日香，大西 充（JAXA）

ISS Demonstration of Oxygen Generation○Masato SAKURAI, Asuka SHIMA, Mitsuru OHNISHI (JAXA)

1. Introduction

References

In order to reduce the amount of water that must be carried on
future space mission closed-cycle air regeneration system isbeing developed1).
In such a system, CO2 exhaled byastronauts as a product of respiration is continuously removed
from the spacecraft’s atmosphere and combined with H2 toproduce water by the Sabatier reaction. The process is exhaledcarbon dioxide is concentrated in an absorbent using a pressure
and temperature swing, then reduced by the Sabatier reaction

1)

M. Sakurai, et.al. “Development of Oxygen Generation
Demonstration on JEM (KIBO) for Manned Space Exploration”
Proc. ICES-2014-125 (2014)(CO2 + 4H2 → CH4 + 2H2O) to produce water and methane.
The water is then electrolyzed to produce oxygen which isconsumed again by the crew.
2. Water Electrolysis
It is necessary to produce dry oxygen for human breathing,
One way to produce dry oxygen from water electrolysis is by
supplying water only to the cathode or hydrogen-generating sideof the cell as shown in Fig. 1, since electro-osmosis produces aforce to expel water from the cathode.
Two water electrolysis cell stacks were prepared by Daiki
Ataka Engineering Co. Ltd. One was a conventional design 10cell stack using a Nafion 114 proton exchange membrane, eachcell having a catalyst surface area of 64 cm2. The other was acontrolled cathode feed design comprising of a 3-cell stack with
an improved electrolyte, each cell having 64 cm2 of catalyst area.
The operating characteristics of the conventional and controlled
cathode feed designs are shown in Fig. 2. The stacks wereoperated at 30oC with a controlled back pressure of 0.1 MPa.
With increasing current density, the cell voltage of theconventional design stack rose rapidly, while that of thecontrolled cathode feed design remained relatively flat.

Fig. 1 Flow diagram of cathode feed SPE water electrolysis

Fig. 2 I-V curve during the cathode-feed water electrolysis

3. A membrane type water/gas separator
A technical issue with space electrolysis systems is that gasliquid separation is fundamentally different in a microgravity
environment to its behavior in a gravity field. A membrane
type water/gas separator consisting of hydrophilic andhydrophobic membranes was used. The membrane is visible
through the transparent cover of the separator.
When the gas/liquid separator is installed vertically, bubbles
collect in its upper side, while bubbles spread throughout the
separator when it is installed horizontally. The pressure dropof the membrane type water/gas separator is shown in Fig. 3.

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Fig. 3 Pressure drop of water/gas separator