27H01
微小重力実験用小型ダストプラズマ実験装置の実験的研究○足立聡（JAXA），東辻浩夫（岡山大学），高橋和生（京都工芸繊維大学）

Experimental Investigation of Small Apparatus for Complex Plasmas Experiments
in Microgravity○Satoshi ADACHI (JAXA), Hiroo TOTSUJI (JAXAOkayama Univ.),
Kazuo TAKAHASHI (Kyoto Inst. Technol.)

1. Introduction
A big issue of complex plasmas experiments in microgravity
is void formation. The void is a region where number density of
micro-particles is almost zero. This makes an observation area
smaller, especially very small in a high power region. Therefore,
we have investigated both mechanisms of the void formation
and a small apparatus being suitable for the microgravity
experiments. The current status of experimental investigation of
the apparatus is reported.

2. Apparatus
The apparatus must be mounted on a rack. The rack having
enough flexibility and room for users, which is installed on the‘Kibo’ pressurized module, is the Multipurpose Small Payload
Rack (MSPR). The MSPR has a user space named Work
Volume, of which dimensions are 600 mm high, 900 mm wide,
and 700 mm long. This may not be a sufficient room for our
experiment because our apparatus should have a plasmachamber, a power supply for plasma formation, plasma
diagnostics, video cameras, sheet laser lighting, and electronics
boxes such as a controller and a data acquisition device atminimum. Some gas bottles accompanying with tubes andvalves may be also required for high purity gas supplies but
these are optional at present.
It is not easy work to design an apparatus optimized for
microgravity experiments from scratch, that is, small andlightweight one which has sufficient performance. Fortunately,
we have an excellent reference, PK-3 Plus 1). PK-3 Plus waslaunched in December 2005 by a Russian Progress cargospacecraft. The operation was started in January 2006 and was
terminated in June 2013. The long operation period of morethan seven years proves the reliability and robustness, which are
indispensable factors in microgravity experiments. Thus we
decided the maximum dimension of the apparatus should be
similar to that of PK-3 Plus.
Another issue is void formation in microgravity. The void is aregion almost without micro-particles. The void is one of themost difficult issues to be solved in microgravity experiments.
Since the void reduces observation area, it is difficult to observe
phenomena requiring larger area such as the critical phenomena.
In addition, the void formation mechanisms may interact withother mechanisms in which we are interested. Therefore, thevoid region must be reduced as much as possible. To suppress
the void formation, it is expected that a flat potential profile inradial direction is helpful though it is difficult to obtain such a
profile. As a starting point, a similar way of supplying RF
current to our larger apparatus is applied since the flat potential
area seems to be obtained near RF electrodes except for nearedges.
The first apparatus is designed as shown in Fig. 1. The
outside dimensions are almost the same as PK-3 Plus. Two RF
electrodes are set at the places near top and bottom flanges.
Each electrode has two feedthroughs so that RF current canflow from one feedthrough to the other. This should be one of
the key techniques to achieve a flatter profile. Unfortunately,
influence of glass wall is not avoidable due to its small size.

Fig. 1

Schematic view of small apparatus

Acknowledgment
This work was supported by JSPS KAKENHI Grant Numbers

25610174.

References
1)

－34－

H. M. Thomas, G. E. Morfill, V. E. Fortov, A. V. Ivlev, V. I.
Molotkov, A. M. Lipaev, T. Hagl, H. Rothermel, S. A. Khrapak, R.
K. Suetterlin, M. Rubin-Zuzic, O. F. Petrov, V. I. Tokarev and S.
K. Kinkalev: New J. Phys., 10 (2008) 033036.

27H02PK-4J における円筒状ダストプラズマ: 理論・シミュレーション○東辻浩夫（JAXA），東辻千枝子（工学院大），高橋和生（京都工繊大），足立聡（JAXA）

Study of Cylindrical Dusty Plasmas in PK-4J; Theory and Simulations1)○Hiroo TOTSUJI (JAXA), Chieko TOTSUJI (Kogakuin Univ.), Kazuo TAKAHASHI (Kyoto Inst. Tech.),Satoshi ADACHI (JAXA)
1. Introduction
In the investigations of fundamental properties of strongly
coupled Coulomb and Coulomb-like systems, dust (fine)particles of micron size in plasmas have been very useful.

2,3)

Under some condition, there appears the central region where
we have no particles or the ‘void’. An example is given in Fig.3.
We have analyzed the condition for the void formation anddetails will be discussed in the presentation.

The only weakness of these particles is the strong response to
the gravitational field. In order to avoid the effect, experiments
4)of the project PK-3 Plus have been successfully performed on
the International Space Station (ISS).
After PK-3 Plus, the project PK-4 is now in progress

5)

and

the experimental apparatus is planned to be launched October
2014. We have constructed the similar apparatus PK-4J andstudied the behavior of (dust) particles to propose interesting
experiments in PK-4. Structures of these apparatus are shown in
Fig.1.

Fig.2 Distribution of electrons, ions, and particles (top), charge
density (bottom left and center), and electrostatic potential(bottom right)

Fig.1 In PK-3 PLUS (left), plasma is generated by rf discharge.
In PK-4 and PK-4J (right), dc discharge with polarity switching
generates plasma and behavior of dust particles is observed in
the central straight part which is a long cylinder.
We consider the system of (dust) particles in a plasma(composed of electrons and ions) with the cylindrical symmetry
and analyze their behavior first on the basis of the driftdiffusion equations. We then analyze the effect of discretenessof dust particles, correlation and structure formations, bynumerical simulations. Our system is composed of plasma(electrons and ions) and dust particles.

2. Analysis Based on Drift-Diffusion Equations

Fig.3. Distribution with void

3. Simulations of Particle Model

Typical examples of distributions obtained by drift-diffusion
equations are shown in Fig.2 where the net charge density andthe electrostatic potential are also plotted. We observe, in thedomain where particles exist, (a) the enhanced charge neutrality,(b) almost flat electron distribution, and (c) compensation of thechange in the particle charge density by that of ion charge.

We then numerically simulate the behavior of particles
following the trajectory of each particle. Typical examplesof particle distribution are shown in Figs.4 and 5:
Particles are organized into shells and a triangular latticewith defects is formed on each shell.

－35－

Fig.4. Examples of shell structures in uniform cylinder(projection onto cross section)

Fig.6. Example of effect of anisotropic interaction. Cross
sectional projection without anisotropic interaction (left), theone with anisotropic interaction (center), and cylinders (shells)
cut-out into planes (right).

Acknowledgements
This work has been supported by JAXA as a Working Group.

Fig.5. Example of configuration within shells

References(cylinders cut-out into planes)
When ions flow along the axis, we have an anisotropic part in
the mutual interaction between particles. This part has the
dipolar nature directed along the axis and has an effect whichtends to align particles along the axis. An example of such effectis shown in Fig.6 where the tendency is observed in
distributions within shells.
The effect of the gravitational field has been also investigatedby simulations in the simplest case where the gravitation works
perpendicularly to the symmetry axis. Examples of results areshown in Fig.7. The circular distribution is compressed along
the direction of the gravity and is moved downward as a whole.
When particles with different radii are included, they areseparated by the mass difference.

1)

H. Totsuji, C. Totsuji, K. Takahashi, and S. Adachi: Int. J.
Microgravity Sci. Appl. 31(2014)55.

2)

V. E. Fortov, A. V. Ivlev, S. A. Khrapak, A. G. Khrapak, and G. E.
Morfill, Physics Reports, 421(2005)1.

3)

G. E. Morfill and A. V. Ivlev, Rev. Mod. Phys. 81(2009)1353.

4)

H. M. Thomas, G. E. Morfill, V. E. Fortov, A. V. Ivlev, V. I.
Molotkov, A. M. Lipaev, T. Hagl, H. Rothermel, S. A. Khrapak, R.
K. Suetterlin, M. Rubin-Zuzic, O. F. Petrov, V. I. Tokarev, and S.
K. Krikalev, New J. Phys. 10(2008)033036.

5)

For example, V. Fortov, G. Morfill, O. Petrov, M. Thoma, A.
Usachev, H. Hoefner, A. Zobin, M. Kretschmer, S. Ratynskaia, M.
Fink, K. Tarantik, Yu. Gerasimov, and V. Esenkov, Plasma Phys.
Control. Fusion 47(2005)B537.

6)

K. Takahashi, M. Tonouchi, S. Adachi, and H. Totsuji: Int. J.
Microgravity Sci. Appl. 31(2014)62.

4. Concluding Remarks
Results of theoretical analysis and numerical simulations arepresented. They will be also discussed in comparison with thoseof parabolic flight experiments.6)－36－

27H03
国際協力による微小重力実験を目指した航空機による実験条件検討
高橋和生（京都工芸繊維大学），○足立聡（JAXA），東辻浩夫（岡山大学）

Experimental Investigation for Collaborative Microgravity Experiments by Parabolic Flights
Kazuo TAKAHASHI (Kyoto Inst. Technol.), ○Satoshi ADACHI (JAXA),
Hiroo TOTSUJI (JAXAOkayama Univ.)

1. Introduction
The next generation apparatus for complex plasmas
experiments in microgravity, PK-4, will be launched this year.
We have carried out parabolic flight experiments in order topropose new ideas with high scientific-significance to the PK-4
international science team. To verify feasibility of the ideas, weprepared a PK-4-like apparatus for the parabolic flight
experiments. Unfortunately, directions and strength of gravity
vary during the parabolic flight. Therefore, we continue
modifying our apparatus to adapt it to the gravity condition. The
present apparatus and major changes are reported.

2. Apparatus and Results
The original PK-4 for microgravity experiments wasdeveloped by the Max-Planck Institute for Extraterrestrial
Physics 1). PK-4 has a long tube of 350 mm in length and 30 mm
in inner diameter. As a result, cylindrical plasma is formed. Thismay bring us new experimental results since the configuration
quite differs from the past apparatuses.
To propose new ideas to the international science team, webegan the parabolic flight experiments. As the first step, anapparatus, which is very similar to PK-4, was prepared. Thisapparatus is relatively large as compared with the rack size on
the airplane. Therefore, it was not easy to integrate theexperimental rack. In addition, we found that the micro-particles
moved along the longitudinal axis when the airplane attitudevaried. It was difficult to stabilize the particle location. We also
found, however, the cylindrical complex plasmas seemed tohave no void. This was excellent news if the void was notformed. Therefore, we began to investigate the void formation
mechanisms.
The modified PK-4-like apparatus was prepared for the next
parabolic flights. The length was reduced to 300 mm to makethe rack integration easier. In addition, the apparatus was
divided into several parts to obtain more flexibility. In theexperiments, we tried to stabilize the particle location bycontrolling the discharge more precisely but did not succeed somuch. The void suppression was also investigated. A newequipment to obtain three-dimensional coordinates of particles
was developed. Further improvement was needed to obtain the
precise coordinates.
By considering those results, we decided the longitudinalaxes of the apparatus and airplane were made perpendicular toeach other though the longitudinal length was decreased. It was
expected that the particles were held by floating potential on thewall and were stabilized when the airplane attitude changed.
The current apparatus is schematically shown in Fig. 1.
Although the longitudinal length is decreased to 175 mm, theplasma should be considered to be still cylindrical due to theratio of the length to the radius (15 mm). Our latest experiment
was carried out two years ago. In the experiments, the particle
location was well stabilized as expected. In addition, the threedimensional particle coordinates were successfully obtained.
From the coordinate data, it was confirmed that the void was
fully eliminated.

Fig. 1

Schematic view of PK-4-like apparatus (PK-4J)

Acknowledgment
This work was supported by the Steering Committee on
Space-Environment Utilization at ISAS/JAXA.

References
1)

－37－

M. H. Thoma, M. A. Fink, H. Höfner, M. Kretschmer, S. A.
Khrapak, S. V. Ratynskaia, M. H. Thoma, M. A. Fink, H. Höfner,
M. Kretschmer, S. A. Khrapak and S. V. Ratynskaia: IEEE Trans.
Plasma Sci., 35 (2007) 255.

27H04
荷電コロイド分散系の分子モデルによる分子動力学シミュレーション○片岡洋右（法政大生命科学）

Molecular Dynamics Simulation on Molecular Model for the Charged Colloidal Dispersion
Yosuke KATAOKA (Hosei Univ.)
1. Introduction

4. Density dependence of structure

The structure in the charged colloidal dispersion isanalyzed by DLVO1) 2) or Sogami model3). These theories
assume low concentration of ion in the statisticalmechanical calculations. This work presents a molecularmodel to be used in molecular dynamics (MD) simulations
for the thermal average.

4.1 Trajectory of large particle
Molecular dynamics simulations are performed at many
densities and temperatures. The structure is analyzed by the
trajectory, the pair correlation function and pressure. The
number of the large particle is 256 in the basic cell.
At low density (d), the solution is like gas phase. At theintermediate density, it has liquid structure like Fig. 2.
The FCC solid (Fig.3) is observed at high density at
T=290K.

2. Large particle and small ion
The large particle must have large charge compared tosmall ion. We assume that the size and mass of large
particle are comparable to that of small ion.
The large particle has 25e (e = charge unit) and mass andsize are the same with those of Rn. The small ion has -e
and mass and size are the same with those of Kr. The
dielectric constant of the solvent is 100.

Fig. 2 d = 1.5 g/cm3, T=290K Fig.3 d = 1.8 g/cm3, T=290K

3. 2-particle system
The interaction energy between the large particles in thesolution uint(r) is calculated by the 2-particle system by
NTV MD.

uint ( r ) = E2 ( r ) − 2 E1

4.2 pressure at several temperatures
The pressure is shown in Fig. 4 as functions of density atseveral temperatures.

(1)

Here E2(r) is the average potential energy of 2-particle
system of the large particle with the separation r, where 50
small ions move at temperature 1K.
The result on E2(r) is plotted in Fig. 1. Attractive
interaction is observed around r = 1 e-9 m, with the depth 7
e-20 J.
-3.5 10 -18-3.6 10 -18

Fig.4 The pressure at T=250K, 290K and T=300K as
functions of density d.

E2(r)/J-3.7 10 -18-3.8 10 -18-3.9 10 -18-4 10

Figure 4 shows the system at T = 290K and d=1 g/cm3 is
close to the critical point of liquid-gas transition if system
is treated as the mixture of large particles and small ones.

-18-4.1 10 -18-4.2 10 -18
0

5

10

15

20
r/A

25

30

35

References401)

Fig.1 The average potential energy of 2-particle system of
the large particle with the separation r

2)
3)

－38－

V. Derjaguin and L. Landau: Acta Physicochim. USSR 14(1941) 633.
E. J. W. Verwey and Th. G. Overbeek: Theory of the Stability
of Lyophobic Colloids, Elsevier, 1948.6.
I. Sogami, Phys. Lett., 96A (1983), 199.

27H05
シリカ－ラテックス混合分散液におけるコロイド結晶の fcc-bcc 相図○篠原忠臣，谷川正幸，曽我見郁夫（京都産業大学），
伊藤研策（富山大学），山中淳平（名古屋市立大学）

Fcc-bcc Phase Diagram in Silica-Latax Mixed System○Tadatomi SHINOHARA, Masayuki TANIUGAWA, Ikuo S. SOGAMI (Kyoto Sangyo University),
Kensaku ITO (University of Toyama), Junpei YAMANAKA (Nagoya City University)
average diameters D of 130nm, 55.8nm, 77.5nm and 87.0nm,

1. Introduction
1)

Hachisu and Yoshimura have investigated colloidal crystals
in charge-stabilized binary systems of latex particles withdifferent sizes by metallurgical microscopic observation andsucceeded to photograph images of the perfect structures ofalloy crystals. General studies, however, have not yet been fully
made for the colloidal crystals in mixed dispersions consistingof different species of particles. Therefore, it is worth toinvestigate the processes of phase transitions of colloidal
crystals in mixed systems. In this research, we pursue structurechanges of the colloidal crystals in the mixed dispersions of thesilica and latex particles by using the Kikuchi-Kossel (K-K)
diffraction method 2).
In the previous study 3), we investigated mixed systems ofpolystyrene-based latex particles (diameter: D = 55.8nm) andrespectively. The latex N558 is the same particle used in theprevious experiment 3). The particle size distributions wereabout /D ～5% for the KE-E10 and /D = 8.78% (5.16% and10.92%) for the N558 (N775 and N870), where  denotes thestandard deviation of the particle diameter distribution. The
ethylene glycol which was used as a solvent for KE-E10 was
replaced with ultra-pure water completely to perform thoroughultrafiltration. After purification with Milli-Q water anddeionization by ion-exchange resin particles, the effective
surface charge densities eff of the colloidal particles were
determined to be 0.12C/cm2 for the silica particles and0.63C/cm2 (0.91C/cm2 and 0.59C/cm2) for the latex
particles N558 (N775 and N870). The properties of the colloidal
particles used in this experiment are summarized in Table 1.

silica particles (D = 170nm). In the single-component
dispersions prior to the mixing, the silica particles formed bodycentered-cubic (bcc) crystals and the latex particles did not
crystallize. In the binary mixtures of these particles, formationof crystals with face-centered-cubic (fcc) structures was verified
by the analysis of the recorded images of K-K diffraction.
Crystal growth in the specimens at low latex fractions took
place with bcc structures and then changed to fcc structures.
In this research, we prepared the specimens for experiments
by mixing the silica particles KE-E10 with each one of threekinds of latex particles (N558, N775 and N870) which havedifferent sizes and surface charges and observed the processesof crystal growth in each of them for 30 days. The observed
structure (bcc or fcc) of colloidal crystals varied according to
the mixing rate, the elapsed time and the observation positions
with different heights. The silica particles KE-E10 have thesmaller size than the particles used in the previous study 3). The
colloid crystals in the single-component dispersion of the silica
particle was confirmed to have only the bcc structure for thevolume fraction of the range of 0.01-0.03.

2. Experiment
The colloid particles used in the study were silica Seahoster
KE-E10 4) produced by Nippon Shokubai Co., Ltd. (Osaka,
Japan) and polystyrene-based latex N558, N775, N870
produced by Sekisui Chemical Co. (Osaka, Japan) which have

Table 1The properties of the colloidal particles

Particles

Diameters

/D

eff

KE-E10 (Silica)

130nm

～5%

0.12C/cm2

N558 (Latex)

55.8nm

8.78%

0.63C/cm2

N775 (Latex)

77.5nm

5.16%

0.91C/cm2

N870 (Latex)

87.0nm

10.92%

0.59C/cm2

To exclude the influence of any ionic strength distribution(caused by relatively slow deionization processes by the ionexchange resins) among several samples, to minimize impurity
ions from outside, and to avoid evaporation of the liquids inside,
all the dispersion samples were introduced into hermeticallysealed quartz cuvettes (height 45mm; width 10mm; inner
thickness 1mm) with an air-tight lid. Ion-exchange resins were
not added in the cuvette. The dispersions began to show
iridescence proving the formation of microcrystals after theirintroduction into the cuvettes. The speeds of crystal growthvaried from specimen to specimen. The cuvettes were kept
standing vertically, and the temperature was held at room
temperature.
We analyzed the colloid crystal structure formed in the
cuvette by using the K-K diffraction method. In the K-K
experiment, the laser beams enter perpendicularly to the wide－39－

surface of the cuvette. We used an Ar laser with wavelength
488nm.

3. Results and Conclusion
For preparation of the specimens, we took out several
milliliters from the dispersion of the latex particle (N558, N775
and N870) and mixed them with the dispersion of the silica
particle KE-E10 at various ratios. The single-component
dispersions of the latex particles (N558, N775 and N870) wereconfirmed not to crystallize.
We observed the structure of the colloidal crystal in eachspecimen for 30 days by using Kikuchi-Kossel line apparatus
and confirmed that the phase transitions (bcc→fcc or fcc→bcc)
take place in many specimens. We recorded the position of thecontainer at which the structural change of the colloidal crystal
was observed. The colloid crystal in the single dispersion ofsilica particle KE-E10 was confirmed to take only bcc for thevolume fraction of the range of 0.01-0.03. As discussed in theprevious report 3), we assume here also that the colloidal crystal
did not form the alloy crystal of the silica particles and the latex
particles and interpret that the colloidal crystals of silica
particles changed their structures from bcc to fcc.
The structural changes of the colloidal crystals to the volume
fractions of the silica and latex particles are shown in Figs. 1, 2
and 3. Observation of the crystal structure was performed every
several days. The graphs drawn in Figs. I-(a), (b) and (c) ( I = 1,
2 and 3) are the phase diagrams observed, respectively, aroundseveral hours, 10 days and 30 days after the preparation of thespecimens. As seen from the phase diagrams, the bcc to fcc
transitions take place depending mainly on the volume fractionof the latex particle rather than that of the silica particle (in therange of 0.01-0.03). The volume fractions that the fcc phasebegins to appear in the dispersions with N558, N775 and N870
are, respectively, about 0.0005, 0.0001 and 0.0003. These

Let us compare the results for the mixed dispersions with thelatex particles N558 and N870 which have nearly the same
surface charge. The bcc-fcc transition is favored to take place inthe dispersion with N870. This is because N870 has the large
diameter. Although the diameters of N775 and N870 are notdifferent so much, the former has higher charge density than thelatter. The bcc-fcc phase transition tends to take place favorably
in the dispersion with N775.
When the surface charge of the particle is large in thecolloidal crystal of the single dispersion, the tendency to takefcc structure is enhanced. Similarly, if the total electric charge ofthe latex particle is large in the mixed dispersion, the colloidal
crystal tends to transform to fcc. When the fraction of the latex
particle becomes increases, the vacant space for the silica
particle decreases. As a result, it is inferred that fcc structure
tend to dominate. To clarify the influence of the latex particles
in detail, however, we have to make further quantitative
analyses of these experimental results.
We will report the data concerning the position dependence ofphase diagrams which show the effects of gravitation in a futurecommunication.

References
1)

S. Hachisu and S. Yoshimura, Nature (London) 283 (1980) 188.

2)

T. Yoshiyama and I. S. Sogami, in Ordering and Phase Transitionsin Charged Colloids, edited by A. K. Arora and B. V. R. Tata
(VCH, New York, 1996), pp. 41–68.

3)

T. Shinohara, T. Kurokawa, T. Yoshiyama, T. Itoh, I. S. Sogami
and N. Ise, Phys. Rev. E, 70 (2004) 062401.

4)

fractions correspond to the particle number 5.5×1012, 4.1×
1011 and 8.7×1011 per 1cm3, respectively.

－40－

J. Yamanaka, N. Ise, H. Miyoshi and T. Yamaguchi, Phys. Rev. E,
51 (1995) 1276.

0.0035

0.003

Volume fraction of N558

0.00250.002

0.00150.001

0.0005

0
0.009

0.014

0.019

0.024

0.029

Volume fraction of KE-E10
bcc

no crystal

Fig. 1(a) Phase diagram for the mixed dispersion with N558 observed around several hours after the preparation

0.00350.003

Volume fraction of N558

0.00250.002

0.00150.001

0.0005

0
0.009

0.014

0.019

0.024

0.029

Volume fraction of KE-E10
fcc

fcc+bccbcc

no crystal

Fig. 1(b) Phase diagram for the mixed dispersion with N558 observed around 10 days after the preparation－41－

0.0035

0.003

Volume fraction of N558

0.00250.002

0.00150.001

0.0005

0
0.009

0.014

0.019

0.024

0.029

Volume fraction of KE-E10
fcc

fcc+bccbcc

fcc→bcc

Fig. 1(c) Phase diagram for the mixed dispersion with N558 observed around 30 days after the preparation

0.0012

Volume fraction of N775

0.001

0.00080.00060.00040.0002

0
0.012

0.017

0.022

0.027

0.032

Volume fraction of KE-E10
fcc

fcc+bccbcc

no crystal

Fig. 2(a) Phase diagram for the mixed dispersion with N775 observed around several hours after the preparation－42－0.0012

Volume fraction of N775

0.001

0.00080.00060.00040.0002

0
0.012

0.017

0.022

0.027

0.032

Volume fraction of KE-E10
fcc

fcc+bccbcc

Fig. 2(b) Phase diagram for the mixed dispersion with N775 observed around 10 days after the preparation

0.0012

Volume fraction of N775

0.001

0.00080.00060.00040.0002

0
0.012

0.017

0.022

0.027

0.032

Volume fraction of KE-E10
fcc

fcc+bccbcc

Fig. 2(c) Phase diagram for the mixed dispersion with N775 observed around 30 days after the preparation－43－0.0009

0.0008Volume fraction of N870

0.00070.00060.00050.00040.00030.00020.0001

0
0.011

0.016

0.021

0.026

0.031

Volume fraction of KE-E10
fcc

fcc+bccbcc

Fig. 3(a) Phase diagram for the mixed dispersion with N870 observed around several hours after the preparation

0.00090.0008Volume fraction of N870

0.00070.00060.00050.00040.00030.00020.0001

0
0.011

0.016

0.021

0.026

0.031

Volume fraction of KE-E10
fcc

fcc+bccbcc

Fig. 3(b) Phase diagram for the mixed dispersion with N870 observed around 10 days after the preparation－44－

0.0009

0.0008Volume fraction of N870

0.00070.00060.00050.00040.00030.00020.0001

0
0.011

0.016

0.021

0.026

0.031

Volume fraction of KE-E10
fcc

fcc+bccbcc

Fig. 3(c) Phase diagram for the mixed dispersion with N870 observed around 30 days after the preparation.

－45－

27H06
微小重力を利用した物理化学研究○夏井坂誠（宇宙航空研究開発機構）

Physical Chemistry Researches under Microgravity○Makoto NATSUISAKA (Japan Aerospace Exploration Agency)

1. Physical Chemistry Researches under Microgravity
The presentation introduces physical chemistry researches
under microgravity in Japan.
1.1 Honey Comb Film Formation under Microgravity
Masatsugu Shimomura (Tohoku University) etc. found that adissipative structure where pores having a uniform diameter are
regularly ordered (“honey comb film”) can be obtained if steam
is added to a casted polymer solution. Although the protocol isvery simple, the uniformity and ordering of the pores are quite
well (Fig. 1). The research team has tried to apply those to
medical application and fabricated larger films. However, a kindof domain formation like a grain boundary in a polycrystalline isobserved in some cases. The research team carried out parabolic
flight experiments to reduce and/or avoid a natural convection
considered to be a cause of this domain formation 1).
1.2 Photochemical Reactions in Super Critical CO2
Yoshihisa Inoue (Osaka University) etc. revealed that anenantiodifferentiating photoisomerization affords chiral isomerand, when the photoisomerization is performed in supercritical
CO2, the enantiomeric excess shows a sudden leap in the nearcritical density region, where the density fluctuation is known tomaximize. This sudden leap is considered to arise from thedifference in CO2 clustering to the diastereomeric exciplex pairprecursor to the enantiomeric products. The research teamspeculated that microgravity might stabilize density fluctuationin supercritical fluids and make the phenomenon describedabove enhanced and carried out parabolic flight experiments.
1.3 Colloid Research with Kikuchi Kossel Diffractometer
The research team organized by Ikuo Sogami (Kyoto Sangyo
University) is interested in particle interactions in charged
colloid dispersions. Crystal formations in those dispersions
which occur when the salt concentrations are decreased were

Fig. 2

Kikuchi Kossel Diffraction

normally explained by DLVO (Derjaguin and Landau, Verwey
and Overbeek) theory, but some observations like measurementsof lattice spacing of the crystals, observation of gas-liquid
coexistence state in colloid dispersions, and observation of void
formations in colloid dispersions can not be explained by DLVO
theory. Those suggest existence of a long range attractive
interaction. The research team has prepared an ISS experiment
by developing ‘Kikuchi-Kossel’ laser diffractometer (Fig. 2).
Although this is simpler and more compact than small angle Xray diffractometer, it can precisely measure crystal structuresand lattice spacing.
1.4 Exploration of Emulsion Stability under Microgravity
Kazutami Sakamoto (Chiba Institute of Science) etc. has tried
to reveal basic mechanisms of emulsions’ formation and thosestabilities. Microgravity can make simplify those mechanisms
by eliminating creaming and accordingly the research teamplans to use microgravity environment. The research team has
communicated with one of the European topical teams, PASTA(Particle Stabilized Emulsions and Foams) to establish a joint
collaboration.
1.5 Impressionistic Physics of Bubbles, Drops and Foams
under Microgravity
Ko Okumura (Ochanomizu University) etc. has investigateddynamics of bubbles, drops and foams via impressionistic
physics which is a powerful way to find out simple laws fromcomplex phenomena. Ko Okumura has started to attract
considerable attention in the field through experiments
performed with the Hele-Shaw cell (a quasi two-dimensionalcell) so that he has been invited to join a number of topicalteams of ESA; FOAM-C, PolarDrop and DOLFINE.

References
1)Fig. 1

Y. Hirai, M. Natsuisaka, T. Mashiko, M. Kanahara, Y. Saito, H.
Yabu, M. Shimomura and K. Tsujii, Int. J. Microgravity Sci.
Appl., 31(2014), 3.

Honey comb film－46－

特別セッション 1

宇宙環境利用科学の将来展望と JASMA の役割
石川正道（日本マイクログラビティ応用学会会長）

Current Issues of Promoting the Space-Environment-Utilization Science and the Role of JASMA
Masamichi ISHIKAWA (President, Japan Society of Microgravity Application)

the panel discussion.

1. Scope and purpose
JASMA has successfully boosted the science of space
Environment utilization, especially in the field of material
processing and physical science under the corporation ofJapanese industry. The scientific outputs are comparable withthose of Europe and USA, and contributing to the continuing
execution of Japanese ISS program. Now, we are required toanswer the next target and plan of microgravity program since
the planned ISS experiments have gone favorably and theremaining number of experiments diminishes in the material andphysical science, on the other hand the number of experimentconcerning life/medical science is increasing.
In this session, the roadmap of microgravity applied scienceis overviewed by reviewing/discussing the outputs of ISS
research, the emerging subjects of basic science, the educational
aspects of microgravity utilization, the industrial enthusiasm inspace tourism, etc. We are convincing that the JASMA’s policyof using space environment to progress the science andtechnology of solving the societal problems is still active andthe participation of society members is strongly anticipated in

2. Issues to be addressed(1) The present status and future plan of Marangoni convection
research, as an example of the microgravity applied science. The
discussion is put forward to the cases of crystal growth andcombustion, etc.
(2) The search of new subjects in basic sciences (physics,
chemistry and life science).
(3) The creation of education/outreach programs to disseminate
the outcome of ISS research to the society.
(4) Panel discussion: the continuation of the existing research
fields, the creation of new projects in the fields of basic sciencesand education/outreach, and the JASMA’s roadmap of
microgravity applied science as shown in the Figure.

Roadmap of Microgravity Science (JASMA Version)
Year

2000

ScientificdomainResearchfieldsFundamental
technologies/
Experimental
facilities

2020

Material processing/
Physical science

2040

Applied science

Human exploration

Fundamental physics/
chemistry

Astrochemistry

Life science

Astrobiology

Life science

Applied science

Fundamental physics/
chemistry・Material・Fluid・Combustion

・Gravit. biology ・Student mission
・Colloid/Soft matter
・Radiat. biology ・Textbook/Video・Plasma physics
・Biophysics
・Experimental kit
・Low temp. physics
・Biotechnlogy ・Space tourism

Technologies

・In-situ observation (Digital microscopy, Interferometer, etc.)
・Molecular imaging (Fluorescent confocal microscopy, etc.)
・Telescience (Automated experiment, Teleoperation, etc.)

Facilities

・ISS, Suborbital vehicle, Sounding rocket, HTV, etc.
・Drop tower, Airplane, Balloon, etc.

－47－

Life science

Education/Outreach特別セッション 2

マランゴニ対流研究を例とした宇宙実験の将来展望○今石宣之（九州大学）

Perspective of Future Space Experiments Based on Marangoni Flow Researches○Nobuyuki IMAISHI (Kyushu Univ.)

1. Marangoni Flow Experiments In Space (MEIS)

2. Marangoni flow experiment projects after MEIS

From Aug. 20 2008 to Feb. 25 2013, five series of spaceexperiments using large scale half zone liquid bridges of high Pr
fluids were carried out in the FPEF (Fluid Physics Experimental
Facility) onboard ISS Kibo to clear some ambiguities inMarangoni flow instabilities in liquid bridge. These series,

After MEIS program, Dynamic Surf. project (Dynamic
Surface Deformation Effects in Transition to Oscillatory
Thermo-capillary Flow in Liquid Bridge of High Prandtl
Number Fluid) was adopted at the 1st IAO (2000) and it's
experiments are now in progress on board ISS.
For the sake of effective use of FPEF, an ITT proposed
JEREMI project (Japanese-European Research Project on
Marangoni Instability) expecting launching a modified liquid
bridge system, in which the ambient atmosphere is much better
defined, in date of 2016. In these projects, the effects of the
dynamic deformation of the liquid bridge surface andheat/momentum transfer through the liquid surface on Mac andflow modes will be quantitatively evaluated.

MEIS1 ～ MEIS5 (Marangoni Experiments In Space), wereconducted by research groups headed by Profs. H. Kawamura
and Nishino. MEIS project was first adopted in 1993 but its
start fell largely behind schedule because of the delay in ISS
construction. Recently, a quick review of MEIS 1 and MEIS2
was publishedl1). The article reviewed Marangoni flow research
activities and developments of experimental facilities.
Objectives of MEIS project can be summarized as follows:
1) Evaluation of the critical Marangoni number (Mac) for flowtransition from a steady axisymmetric to 3-D oscillatory flow
as function of liquid bridge size, aspect ratio, Pr number. andbridge shape (liquid volume).
2) Observation of the structure of the oscillatory flow by meansof. 3D-PTV system, photo-chromic dye surface velocimetry
and IR camera.
3) Observation of flow transition process from steady flow toperiodic oscillatory flow and further to chaos/turbulent flow.
4) Possibility of Particle Accumulation Structure (PAS) in liquid
bridge and semispherical hanging drop under G condition.
These experiments can be done only in FPEF onboard ISS
which allows large size liquid bridge (diameter up to 50mm andaspect ratio up to 2.0), large temperature difference and longevolution time for weak disturbances to grow up to detectable 3D oscillatory flow state.
So far, published MEIS results suggest that the objectives ofthe program were successfully achieved. Results indicate thatthe size dependency of Mac is much smaller than those of thepreviously reported Mac obtained by short time G experiments.
This reveals that too fast temperature ramping rate causes
significant delay the growth of the disturbances and increases
the observed Mac and also the hydrothermal wave instability is
the main mechanism of the instability. However, more detailed
works on the effects of aspect ratio, surface shape, Pr number
and heat exchange with the ambient atmosphere on Mac andflow modes are necessary. More results of MEIS will bereported as soon as the team finishes analyses of the huge data
set sent/returned from space.

3. Possible future works
MEIS experiments revealed that transition process from 2-D
axisymmetric steady flow to oscillatory and further to chaos
based on the local surface temperatures by using IR camera andthin thermocouples. Under large temperature differences, theflow may become turbulent. Analysis of such thermocapillaritydriven turbulent flow, if any, will open a quite unique field in
fluid physics. Quantitative discussion on such turbulent flow
requires correlations of local temperature and velocities in thebulk as well as on the surface. However, present FPEF has nosuch device to measure these local values. Under very large
temperature difference, fluctuation of local temperature causes
large distortion of image and optical path of laser-Doppler
system and gives big noise for a hot-wire anemometer.
Development of new velocity measurement system is essential.
Such a velocity measurement system will be effectively applied
to various fluid dynamics researches and also to crystal growthresearch.
Accomplishment of space experiments needs long-term
collaboration and discussions in the project team made up of
experts in various fields to develop new concept, new devices
and highly sophisticated modeling and theoretical/numericalanalyses.

References
1) "Review of MEIS experiments", Int. J. Microgravity Sci. Appl., 31
Suppleme nt (2014).

－48－

特別セッション 3

宇宙環境利用科学ロードマップの策定に向けて○稲富裕光，足立聡，橋本博文，石岡憲昭（ISAS/JAXA）

Toward Establishment of Roadmap for Space Environment Utilization Science○Yuko INATOMI, Satoshi ADACHI, Hirofumi HASHIMOTO and Noriaki ISHIOKA (ISAS/JAXA)

Scope and purpose
The Global Exploration Roadmap shown in Fig. 1 is being
developed by space agencies participating in the International
Space Exploration Coordination Group (ISECG) 1). The
roadmap builds on the vision for coordinated human and robotic
exploration of our solar system that was established in The
Global Exploration Strategy: the Framework for Coordination(May 2007). The roadmap reflects a common long-range human
exploration strategy that begins with the ISS and expands
human presence into the solar system, leading to human
missions on the surface of Mars. The ISS provides theopportunity for research and technology demonstrations which
benefit from its unique location. It is also the foundation of
exploration, advancing critical capabilities to take humans
further into space and reducing the cost of human space flight.
Steering Committees for Space Science and for SpaceEngineering of ISAS/JAXA are now drawing up a roadmap for
space science and exploration in Japan since June, 2013. In theframework of the roadmap future space experiment missions
related to space environment utilization science will be mainly
categorized as small-scale projects adopted by competitiveenvironment in ISAS. It means that the competitors will bechallenging missions of space science and space engineering.
On the other hand it is the fact that the concrete future planthat looked ahead to for ten years and 20 years later in Japan has
not been discussed in the space environment utilization science.
Figure 2 shows a draft idea of a future road map for space life
science 2) for reference. However, even for the research field,
clarification of the implement priority of the space mission will
be strongly required in a limited budget of JAXA. For the
breakthrough it goes without saying that the related researchcommunities should work out a crossover and comprehensive
plan for the future. In the present symposium the authors would
like to discuss establishment of a road map for microgravity
sciences with the members of JASMA.

References1)

http://www.nasa.gov/sites/default/files/files/GER-2013_Small.pdf

2)

N. Ishioka: J. Jpn. Soc. Microgravity Appl., 28 (2011) 124.

Fig. 1 Global Exploration Roadmap 1).

Fig. 2 Future roadmap for space life science research 2).

－49－

特別セッション 4

技術と科学の共生：微小重力研究の教育的成果○中村祐二（豊橋技科大）Co-operation of Engineering and Science: Educational Outcome brought by Microgravity
Researches○Yuji NAKAMURA (Toyohashi Univ. Tech.)

1. Introduction

3. Impact in Education

When we talk about the “microgravity (-utilized) research”, it
contains at least two issues. Generally, one is pure science
outcome and the other is technological/engineering supports tomake the scientific outcome is effectively done. With thisregards, these two issues always co-exists as essential items andthey are “inter-dependent” pair. In other words, either of themcannot be self-stand and there is no superiority to grade them.
Let us consider the effectivity this feature in education.

Recently, Japanese Ministry of Education (MEXT)
encourages engineering universities to develop the new
educational program to develop “needs-oriented”, notconventional “needs-oriented” type of graduates. To do so, it
is necessary to have “sense” of back-tracing the problem(consider what is the necessary task to fulfill the goal deeply andpick the right essences to dig with). To do so, interdependentproblem is a good example for training. In this sense,
microgravity research (especially, engineering goal path) shallbe considered as effective “tool” for future engineers’ education.
Let me give one example for engineering problem in space;such as cooking. Fig.2 shows the illustration of cooking ofegg (sunny-side-up). Under normal gravity, egg is pushed overthe hot plate and large area is spread to receive the heat from theplate. Hot plate is heated by flames uniformly assisted bybuoyancy-induced flow so that cooking performance is goodand easy. Under microgravity, on the other hand, no force topush the egg toward the plate so that heated area should bemuch smaller. In addition, flame in reduced gravity does notgood to heat up the plate uniformly. Obviously the same
design/strategy of cooking might not work. To propose new
design of cooking in space (as real “engineering” problem), wemust know the heat transfer and boiling phenomena in reduced
gravity as essential matter. Without the sufficient scientificknowledge, it would be impossible to make this happens.

2. Interdependency of Science and Engineering
Fig. 1 summarizes how they are inter-dependent. In the left
path in Fig.1, it is shown how to achieve pure scientificoutcome assisted by engineering development (e.g., hardware,measurement system) as typical example. Similarity, we canfind the right path such as the engineering problem should be
solved under microgravity environment assisted withmicrogravity researches. This is demanded when manned
mission or long-term stay in space is the target. As it isunderstood, any topic in space science (left path) as well as
space engineering (right path) should need microgravity
environment and interdependency of science and engineering.
In this sense, space-utilization engineering (in Japanese, 宇宙
環 境 利 用 工 学 ) should stand separately to hold suchinterdependency feature.

Fig.2 Cooking eggs in normal gravity (left) and microgravity(right)

4. Remarks

Fig.1 Interdependent of science
microgravity-utilized research.

andengineeringinMicrogravity researches are basically inter-dependentproblems of science and engineering, it must be unique as well
as strong educational “tool” to train ones to be professional
engineers. Appropriate scheme (educational program) utilizedof microgravity research is welcome to propose.

－50－

特別セッション 5

微小重力実験の共同作業型課題としての活用範囲の広がり○森義仁（お茶大）Widening Application of Microgravity Experiments to Teamwork-solved Subjects○Yoshihito MORI (Ochanomizu University)

1. Teamwork to Solve Complicated Subjects
The subjects to be solved are becoming complicated in theacademic and industrial worlds and the cooperative teamwork
activity made by the group consisting of the members comingfrom the various areas is required to solve them. The members
are expected to train in the suitable programs.
The teamwork training programs frequently appear inengineering education but less in science education. Then we try
to think what kinds of the effective training programs can beprepared in science education. An idea is to employ
microgravity experiments as the subjects and some tested
example can be shown in the present talk.

2. The Related Examples in Education
2.1 Undergraduate Student Academic Activity
In science education, there is less teamwork activity programs
because in the scientific research situation an individual
research subject is typically given to a student. Before 2014, a
good opportunity was prepared as a teamwork-solved subject
for undergraduate students. It’s the microgravity experimentcontest for Japanese and Asian students. There students meet
together, show their ideas, discuss them each other to come tothe single proposal. When the proposal is accepted they start tomake an experimental instrument (Fig.1) and optimize theexperimental conditions to get the goal by conducting expected
experiments in a parabolic flight.

students in science and engineering but it actually opens to theother areas. The collaborations between the microgravity
experiment and art make non-science and non-engineering
students feel the microgravity experiment more familiar.

2.3 High School and University Collaboration
In these years, we can find richness of diversity incollaborations between high schools and universities to prepare
the highly potential human resource to bring the developments
in our country. There are many types of programs and an
expected and potential program is group-working activity on the
microgravity experiment. Figs.3 and 4 shows the program
prepared for the high school student by the host university.
The lecture of the parabolic flight microgravity experiments wasgiven to the students and the student met the 60-year history of
the microgravity experiment contest with the demonstration
with the “FUWATTO-KUN”. The high school student groups
tried to make an original experiment proposal.

3. Perspectives
Although the microgravity experiment contest was stopped, we
confirmed that there was the high effectiveness to motivate
young undergraduate students. The two rest examples of thestudent campus festival and the high schools and universities
collaborations can be expected as the good teamwork-solved
subjects.

2.2 Campus Festival
A student campus festival is a traditional event in a university.
In these years, more academic exhibitions have appeared there,
for example the presentations of the researches about theworldwide environmental issues, the report about the aid
activity for developing countries and so on. One of those was
the ten-year history of the microgravity experiment contest(Fig.2). There the 60 accepted proposals in the ten years wasshowed and the 0.1-sec microgravity situation was demonstrated
with the instrument, FUWATTO-KUN, which a 2-m drop tower.
The movies and photographs relating to the microgravity
experiments were projected. In particular, much attention was
attracted by the collaborations between the microgravity
experiments and art, which were the microgravity dance
motivated by the ancient art and the sound sculpture of thefloating particles. It generally seems that an opportunity of the
microgravity experiments is available for undergraduate－51－

Fig.1 Assembled machine

Fig. 3 Group-working

Fig.2 Campus Festival

Fig. 4 Proposals

27A01

ISS 利用 TPF 沸騰二相流実験
その１．概要○大田 治彦, 新本康久, 廣川 智己(九州大学), 浅野 等(神戸大学), 河南 治(兵庫県立大学),
鈴木 康一(山口東京理科大学), 今井 良二(室蘭工業大学),
岡 利春, 友部 俊之, 宇宿 功史郎, 島田 雅喜(IHI エアロスペース),松本 聡, 栗本 卓, 高岡 秀充, 坂本 道人, 川崎 春夫, 澤田 健一郎(宇宙航空研究開発機構)

Experiments of Boiling and Two-phase Flow Onboard ISS:
1. Outline of Experiments○Haruhiko OHTA, Yasuhisa SHINMOTO, Tomoki HIROKAWA (Kyushu Univ.),
Hitoshi ASANO (Kobe Univ.), Osamu KAWANAMI (Univ. of Hyogo),
Koichi SUZUKI (Tokyo Univ. of Science, Yamaguchi), Ryoji IMAI (Muroran Institute of Technology),
Toshiharu OKA, Toshiyuki TOMOBE, Koushiro USUKU, Masaki SHIMADA (IA),Satoshi MATSUMOTO, Takashi KURIMOTO, Hidemitsu TAKAOKA, Michito SAKAMOTO,
Haruo KAWASAKI, Kenichiro SAWADA (JAXA)
Abstract
Boling experiments under microgravity conditions areuseful for understanding of interfacial phenomena and heattransfer under the terrestrial condition in addition to theirapplication to the innovative two-phase thermal
management systems for space development. To obtain thereliable and coherent data for the gravity effects on flow
boiling, space experiments onboard ISS are to be
performed. There are three targets: (i) To clarify gravity
effects on heat transfer coefficients and critical heat fluxes
in a wide range of flow and heating conditions, (ii) To
clarify the mechanisms of heat transfer in various flow
regimes under microgravity conditions, (iii) To establish adominant force regime map by the clarification of exact
boundaries between the buoyancy-, inertia- and surface
tension- dominated regimes. The above subjects areschematically shown in Figs.1-4. Two heated sections of ametal tube or transparent tubes1) is switched in orbit asshown in Fig.5. The former is prepared for the

Fig. 1

measurement of detailed heat transfer data and critical heat
fluxes, while the latter is developed for the data acquisition
with real-time interfacial observation under selected
experimental conditions. In the downstream of both heatedsections, non-heated test sections are connected for thedetailed observation of interfacial behaviors by using high-speed cameras. Table 1 shows experimental conditions. An
engineering model was already developed, and a flightmodel is under development. A series of experiments inorbit is scheduled in 2016.

Acknowledgement
The authors express appreciation for the support of TPF
project by JAMSS, JSF, and for the contribution by Prof.
Kiyosumi Fujii in Nara Institute of Science and Technology
moved from JAXA.

Reference
1) H. OHTA, Microgravity Heat Transfer in Flow Boiling:
Advances in Heat Transfer, 37, 2003, 1.

Effect of gravity on heat transfer (1/2).

Fig. 2－52－

Effect of gravity on heat transfer (2/2).

Fig. 3Fig. 4

Critical Heat Flux conditions.

Dominant force regime map.

Table 1 Experimental condition for flow boilingonboard ISS.
Power supply
Test fluid
Inner diameterof heated tubes
Heated length
Mass velocity
Inlet liquid subcooling
Vapor quality range
Heat flux
Fig. 5Outline of test loop for ISS flow boiling experiment "TPF".

－53－

250 W
n-perfluorohexane
di = 4 mm
I = 50 mm  2 and 5 mm  1
for transparent heated tube
I = 368 mm
for copper heated tube
G = 30 – 600 kg/m2s
Tsub = 0 – 30 K
x = 0 - 0.9
q = 1 – 400 kW/m2

27A02
ISS 利用 TPF 沸騰二相流実験

その２．実験装置の開発○高岡秀充，松本聡，栗本卓，坂本道人，澤田健一郎，川崎春夫（宇宙航空研究開発機構），
大田治彦，新本康久（九州大学），鈴木康一（山口東京理科大学），浅野等（神戸大学），
河南治（兵庫県立大学），今井良二（室蘭工業大学），岡利春，友部俊之，宇宿功史郎，
島田雅喜（株式会社 IHI エアロスペース）

Experiments of Boiling and Two-phase Flow Onboard ISS:
2. Development of the Experimental Equipment○Hidemitsu TAKAOKA, Satoshi MATSUMOTO, Takashi KURIMOTO, Michito SAKAMOTO,
Kenichiro SAWADA, Haruo KAWASAKI (JAXA), Haruhiko OHTA, Yasuhisa SHINMOTO (Kyushu Univ.),
Koichi SUZUKI (Tokyo Univ. of Science Yamaguchi), Hitoshi ASANO (Kobe Univ.),
Osamu KAWANAMI (Univ. Hyogo), Ryoji IMAI (Muroran Inst of Tech),Toshiharu OKA, Toshiyuki TOMOBE, Koshiro USUKU, Masaki SHIMADA (IHI AEROSPACE Co., Ltd.)

1. Introduction
Recently, because of increase in the space platform size andits power consumption, the amount of waste heat has becomelarger. Boiling and two-phase flow becomes powerful means
for this system, because boiling is one of the most efficientmodes of heat transfer due to phase change. Therefore, theexperiment on boiling and two-phase flow under microgravity
conditions is proposed and selected as a candidate subject ofISS experiments1).
In this paper, the test results of the Engineering Model(EM) for the microgravity experiment in order to verify theperformance and feasibility to be used in the International
Space Station (ISS), and the some improvements in the Proto
Fright Model (PFM) are reported.

vibration of the pump has been identified as the cause, its
axial alignment and material of the axial bearing werereviewed.
On the fabriation of the PFM, we have made some
improvements in the parts of TPF-EE in order to satisfy thescientific and safety requirments.

2. Experimental Equipment
Two-Phase Flow Experiment Equipment (TPF-EE) isshown in Fig.1. The dimension is 500 x 800 x 650 mm and themass is 140 kg. TPF-EE is accommodated in the Work Volume(WV) of the Multi-purpose Small Payload Rack (MSPR)
onboard the ISS/Kibo.
The test loop has two different heated sections, i.e.
transparent heated tube and metal heated tube, in which purenormal-perfluorohexane is used as test fluid. Using thisapparatus, we intend to perform the experiment of the heattransfer with boiling flow. At the same time, we study themechanism of liquid-vapor behaviors in two-phase flow underthe microgravity conditions.

3. Results

Fig. 1

Fig. 2

Several tests using the EM revealed some problems. One ofthe problems was the pressure fluctuation in the circulated
fluid. Figure 2 shows the pressure oscillation with the applied
voltage to the pump. It reveals that the pressure oscilllation
increases with applied voltage being more than 4V. Since the－54－

Picture of the Engineering Model.

Pressure fluctuation with applied voltage to the pump

References
1) S. Baba, T. Sakai, K. Sawada, C. Kubota, Y. Wada, Y.
Shinmoto, H. Ohta, H. Asano, O. Kawanami, K. Suzuki, R.
Imai, H. Kawasaki, K. Fujii, M. Takayanagi, S. Yoda,
Journal of Physics: Conference Series, 327 (2011) 012055

27A03
ISS 利用 TPF 沸騰二相流実験
その 3. 蒸発部の開発○河南 治，今井 智敬，大久保 正基（兵庫県大），大田 治彦, 新本 康久，廣川 智己（九大），
浅野 等（神大），鈴木 康一（山口東理大），今井 良二（室工大），岡 利春，友部 俊之，
宇宿 功史郎，島田 雅喜（IA），松本 聡，栗本 卓，高岡 秀充，坂本 道人，川崎 春夫，
澤田 健一郎（JAXA）

Experiments of Boiling and Two-Phase Flow Onboard ISS:
3. Development of Evaporation Section○Osamu KAWANAMI, Tomotaka IMAI, Masaki OKUBO (Univ. Hyogo), Haruhiko OHTA,
Yasuhisa SHINMOTO, Tomoki HIROKAWA (Kyushu Univ.), Hitoshi ASANO (Kobe Univ.), Koich SUZUKI(Tokyo Univ. Sci., Yamaguchi), Ryoji IMAI (Muroran Inst. Tech.), Toshiharu OKA, Toshiyuki TOMOBE,
Koushiro USUKU, Masaki SHIMADA (IA), Satoshi MATSUMOTO, Takashi KURIMOTO,
Hidemitsu TAKAOKA, Michito SAKAMOTO, Haruo KAWASAKI, Kenichiro SAWADA (JAXA)

1. Introduction
Boiling and two-phase flow loop system can be achieved
high-performance heat exchange and heat transfer for thethermal management of space system. However, boilingphenomena in microgravity is unclear until now. Authors plan
two-phase and flow boiling experiment as called “TPF”,
onboard “KIBO”, which is Japanese Experimental Module in
the International Space Station. Systematic experiments on flow
boiling and two-phase flow will be performed by using longterm microgravity period in ISS for establishment reliabledatabase, which is required for the design of the thermal
management in the future space system.
Here, we report the evaporation sections in the TPF loop as
shown in Fig. 1: the copper heated tube section and thetransparent heated tube section will be illustrated.

2. Evaporation Sections
Fig. 2 shows images of the copper heated section and thetransparent heated section. The heated length of the copper tube
is 363 mm, and inner diameter of the tube is 4 mm. The outerwall of the tube is covered by two metal heaters; main and sub
heaters. 10 thermocouples are installed at 0.5 mm location from

Fig. 1

Outline of test loop for ISS flow boiling experiment.

Fig. 2

Images of the metal heated tube section (Top) and thetransparent heated section (Bottom).
the inner-wall surface.
In the ISS experimental loop, three transparent heated tubes,
segment 1, 2 and 3, are installed as an evaporating part. The
heated lengths of each segment are 50 mm for segment 1 and 2
and 5 mm for segment 3. The inner diameter of all tube is 4 mmwith 1 mm wall thickness, and the inner-wall of the tube iscovered by extremely thin gold film as using not only a heater
but also resistance thermometer, that is, the averaged inner-walltemperature entire heated length can be measured. At the sametime, gas-liquid behavior of flow boiling can be observed
through the gold film on the wall.
The single-phase heat transfer results of transparent heatedsection in the EM facility test shows in Fig. 3. In laminar andturbulent flow regions, the experimental results have a good

"TPF".

－55－

Fig. 4
Fig. 3Single-phase heat transfer at Segment 1 in thethe relation between exit quality and heat transfer

coefficients at each segment during flow boiling experimenttransparent heated tube section.

by using transparent heated test section in EM facility.

agreement with Sieder-Tate and Dittus-Boelter equations.
Fig. 4 shows the relation between exit quality and heattransfer coefficients at each segment during flow boilingexperiment by using transparent heated test section in EM
facility. At segment 3, the abrupt decrease of heat transfer
coefficient caused by dryout could be found. The value ofcritical heat flux at segment 3 was 52 kW/m2. It is coincide with
55.6 kW/m2 derived from Katto’s equation.

Acknowledgement
The authors express appreciation for the support of TPF
project by JAMSS, JSF, and for the contribution by Prof.
Kiyosumi Fujii in Nara Institute of Science and Technology
moved from JAXA.

－56－

27A04
ISS 利用 TPF 沸騰二相流実験
その４．観察部での気液界面構造の計測○浅野 等，五明 泰作（神戸大），大田 治彦，新本 康久（九州大），河南 治（兵庫県大），鈴木 康一（山口東京理科大），今井 良二（室蘭工大），岡 利春, 友部 俊之, 宇宿 功史郎,
島田 雅喜（IHI エアロスペース），松本 聡, 栗本 卓, 高岡 秀充, 坂本 道人, 川崎 春夫,
澤田 健一郎，栗本 卓，駒崎 雅人（宇宙航空研究開発機構）

Experiments of Boiling and Two-Phase Flow Onboard ISS
4. Measurements of Gas-Liquid Interface Structure at the Observation Section○Hitoshi ASANO, Taisaku GOMYO (Kobe Univ.), Haruhiko OHTA, Yasuhisa SHINMOTO (Kyushu Univ.),
Osamu KAWANAMI (Uni. of Hyogo), Koich SUZUKI (Tokyo Univ. of Science, Yamaguchi),Ryoji IMAI (Muroran Institute of Technology), Toshiharu OKA, Toshiyuki TOMOBE, Koushiro USUKU,
Masaki SHIMADA (IHI Aerospace), Satoshi MATSUMOTO, Takashi KURIMOTO, Hidemitsu TAKAOKA,
Michito SAKAMOTO, Haruo KAWASAKI, Kenichiro SAWADA (JAXA)
Abstract

method using a stainless steel rod with various diameters. The

Flow visualization of vapor-liquid two-phase flows isimportant to understand heat and flow characteristics. In
reduced gravity and low mass velocity condition, flow structure
will be much different from that in the normal gravity condition.
Two-phase flow observation sections are installed to visualize
gas-liquid interface structure with high spatial and temporal
resolution.
Observation test section is placed at the just downstream ofrod configuration is shown in Fig. 4. The rod was inserted in thetested tube filled with the liquid FC72 to form simulated liquideach heating section as shown in Fig. 1. The channel diameterof the observation section is the same as the heating section at
4.0 mm, and the observation section is smoothly connected tothe heating section. Requirements on the observation section are
three-dimensional measurement of interface structures in twophase flows, bubble velocity in intermittent flows, wave velocity
in annular flows, void fraction, and pressure loss. For threedimensional observation, a method of stereoscopic photography
by which two images from two orthogonal directions can be
photographed by one camera is applied. The optical system
consists of one high frame rate video camera, four metal mirrors,
two LED lighting for the back-lighting. The arrangement of thefilms as shown in Fig. 5. Measured values of the thickness fromthe image are compared with given thickness from thedifference between the inner diameter and the rod diameter. The
compared results is shown in Fig. 6. It can be seen that theactual size can be measured from the image with ± 4 % accuracy.
Next, measured results of time-average void fraction from thecontinuous images of two-phase flows were compared thevalues measured by a quick closing valve method. The
compared results is shown in Fig. 7. It can be seen that the void
fraction can be measured from the image with ± 5 % accuracy.

Acknowledgement
The authors express appreciation for the support of TPF
project by JAMSS, JSF, and for the contribution by Prof.
Kiyosumi Fujii in Nara Institute of Science and Technology
moved from JAXA.

optical equipment is shown in Fig. 2. The test section was asquare pole of transparent polycarbonate to avoid the refraction
at the outside surface. A circular channel with 4 mm in diameter
was drilled at the center of the square pole.
Examples of photographed images are shown in Figs. 3 (a)and (b). These images were taken with the frame rate of 1000
fps. The size of image pixel was about 28 m. The threedimensional structure of vapor-liquid interface could be
visualized well. In Fig. 2 (a), bubble positions and their shapes
were clearly visualized. In Fig. 2 (b), liquid film structure,especially the difference in film thickness along the flow andcircumferential directions, are clearly visualized.
To evaluate the accuracy in the measurement of sizes, such as
liquid film thickness, bubble diameter, moving distance, two
methods of the calibration were conducted. The first is a static－57－

Fig. 1 Outline of test loop for ISS flow boiling experiment.

Metallic mirror
Flange

Camera3.8
2.0, 2.1,
Diameter [mm]······, 3.6, 3.7, 3.8

Fig. 4 SUS rod with various diameter for calibration.

Measureing thickness [mm]LED
Test section
Metallic mirror

Right side

Fig. 2 Arrangement of the optical system.
Left side1+4% ±0%-4%left sideright side

0.75

0.5

0.25

0
0

0.25

0.5

0.75

1

Given thickness [mm]Fig.5 Image ofchannel withcalibration rod.

Fig.6 Comparison of liquid thickness between
measured result from image and given values
using calibration rod.
+5% ±0%Flow

Void fraction m, I

1(a) Mass flux : 300 kg/(m2s)

0.9

m, I

-5%

0.8
0.7
0.6
0.5
0.4
0.4 0.5 0.6 0.7 0.8 0.9

1

Void fraction m, CM

Fig. 7 Comparison of average void fractions between themeasured results from the observed images, αm, I, and the results
by a quick closing valve method, αm, CM .

References
Flow

1)

(b) Mass flux : 200 kg/(m2s)Fig. 3 Examples of the photographed images.

－58－

T. Gomyo, H. Asano, H, Ohta, Y. Shinmoto, O. Kawanami,
T. Kurimoto, M. Komasaki, A. Matsumoto, Japanese
Journal of Muntiphase Flow, 27, 5, 2014, 547-554

27A05
ISS 利用 TPF 沸騰二相流実験

その 5．凝縮器の開発○今井良二（室工大），鈴木 康一（山口東京理科大），川崎 春夫（JAXA），大田 治彦, 新本康久（九州大）, 浅野 等（神戸大）, 河南 治（兵庫県立大）, 岡 利春, 友部 俊之, 宇宿 功史郎,
島田 雅喜（IA）, 松本 聡, 栗本 卓, 高岡 秀充, 坂本 道人,澤田 健一郎（JAXA）

Experiments of Boiling and Two-Phase Flow Onboard ISS:
5. Development of Condenser○Ryoji IMAI (Muroran Institute of Technology ), Koich SUZUKI(Tokyo Univ. of Science, Yamaguchi),Haruo KAWASAKI(JAXA), Haruhiko OHTA, Yasuhisa SHINMOTO(Kyushu Univ.),
Hitoshi ASANO(Kobe Univ.), Osamu KAWANAMI(Univ. of Hyogo), Toshiharu OKA, Toshiyuki TOMOBE,
Koushiro USUKU, Masaki SHIMADA(IA), Satoshi MATSUMOTO, Takashi KURIMOTO,
Hidemitsu TAKAOKA, Michito SAKAMOTO, Kenichiro SAWADA(JAXA)

1. Introduction
On the manned spacecraft or facility, thermal management,such as heat transport and heat rejection is one of the essential
technology to be established. Especially two phase thermal
management technology utilizing latent heat transport isfavorably effective for the application to a large scale spacecraft
system in future since the high amount heat transport andrejection are practiced by less flow rate of working fluid.
The project on two-phase boiling flow experiments has been
carried out as the so-called TPF “Two Phase Flow” promoted by
JAXA for these several years. In this project, interfacial
behaviors and heat transfer characteristics in boiling two-phaseflow under microgravity condition will be investigated. The
heat generation in the boiling test section including heat
supplied into the working fluid must be transported to ISS
thermal management system through the condenser assembled
on this experimental test loop.
The present paper introduces the thermal design and theevaluation test for the condenser system.

Fig.1 Structure of condenser for TPF experimental fluid loop

2. Structure of condenser for TPF experimental loop

3. Arithmetic thermal model of condenser

The condensing tube was assembled on a flat type cold plate
which had employed for on-orbit system and high reliability inpractice. Figure 1 shows structure of the condenser. The

Figure 2 shows an arithmetic thermal model for the condenser.
It is considered that one dimensional thermal path is applied
from fluid in the condenser tube to cold water in the cold platethrough the condenser tube wall, the adhesion, and the coldplate wall to obtain thermal resistance by thermal conduction
and heat transfer. The condensation heat transfer coefficientunder microgravity condition is given as a half value from theempirical equations for the ground based condition. The halfvalue is assumed from the fact that the condensation length
under microgravity is twice as long as under 1-g condition by
the numerical calculation1).
Thermal resistance throughcondenser tube wall is calculated through two dimensional
thermal conduction analysis. Fluid temperature, quality, andlocal pressure are calculated via above thermal resistances.

condenser is square rod of 11mm ×11mm with a circular flow
path of 6mm in diameter. Each rod is connected by U-shape
tube. The square tube is made of copper in order to realize lessthermal resistance by the high thermal conductivity of wall
section. High heat conductive adhesion is used for the joint
surfaced between the condenser tube and the cold plate. In thecondenser system, fluid temperature at inlet/outlet of hot side as
well as tube wall are planned to be measured in order to obtain
local and overall condensation heat transfer coefficient.

Cold Plate
Condensation
Tube
□11

φ6

Cooling Water
Passage－59－

Condensation
Tube

Tc

Thermal Resistance [K/(W/m)]

Wtp=
1.5xD coFluid in Condensation
Tube
Condensation Heat Transfer

Ttw1
W tp=
D D
1.5xDco co ci

TC

Ttw1

Tp
Tp

tbp
Hcl
Cooling Water
Passage

Tcw

Wall of Condensation
Tube
Heat Conduction of Tube Wall
Bottom of Tube
Conduction of Adhesives

Tcl

Tcw

Cold Plate Surface
Cooling Water Heat Transfer

Adhesives
Tcl

Cooling Water

Fig. 2 Arithmetic thermal model of condenser structure ofcondenser

1
0.1
0.01
0.001
0.0001
0.00

0.50
1.00
1.50
Length from Inlet [m]Condensation Heat Transfer
Conduction of Adhesives8
Total

Numerical calculation was conducted by the arithmetic
thermal model on the following conditions shown in Table 1.

2.00

Heat Conduction of Tube Wall
Cooling Water Heat Transfer

Fig.3 Thermal resistance at local point

Table 1 Data for numerical calculation
Hot Side
FC-72
Cold SideWater
Hot Side
Inlet Pressure
0.103MPa
Inlet Temperature
55.7 C
Inlet Quality
1.0
Mass Flow Rate
0.0042kg/s
Cold Side
Inlet Temperature
23C
Mass Flow Rate
45kg/hHeat Transfer Coefficient2000 W/m2/K
Condenser Inner Diameter
6mm
Tube
Lengthm (6mm)

Temperature [C]

100.0

Fluid

80.0
60.0
40.0

φ6mm
φ4mm

20.0
0.0
0.00

0.50

1.00

1.50

2.00

Length from Inlet [m](a)Temperature in condensing tube
Subcooled Temperature
[K]

15.0

φ6mm
φ4mm

10.0

We provided the additional following condition as required
specification for the condenser;
Outlet sub-cool temperature is 10K at 400W for theequivalent mass flow rate. This condition was determined inconsideration of measured suction performance of mechanicalpump.
Figure 3 shows the distribution of thermal resistance on flow
path. The thermal resistance by condensation increases toward
downstream section since the condensation liquid film becomes
thicker as shown in Figure 3. We can see that other major
thermal resistance is achieved in the cold water passage, andthat the resistance at the tube wall and the adhered portion
between the condensation tube and the cold plate aresufficiently small. It is found that the thermal resistance oncondensation side is dominant at the downstream.
Figure 4 shows distribution of fluid temperature and sub-cool
temperature with tube length in the hot side passage. It is
confirmed in the experiments that 9K in sub-cool temperature
for the 6mm-tube and 14K for the 4mm-tube are obtained,
which indicated achievement of our target. We had alreadyconfirmed that the cold plate had enough area to install thecondensation tube with required length.

5.0
0.0
0.00

0.50

1.00
1.50
Length from Inlet [m]2.00(b)Sub-cooled temperature in condensing tube
Fig.4 Temperature and sub-cool temperature resistance at
local point

4. Results of evaluation test for BBM condenser onground based condition
BBM test on ground based condition was carried out toconfirm performance of condenser.
Test loop for the condenser system is shown in Fig.5.
Working fluid, FC72, circulates the condenser loop from aheating bath shown in Fig.5. Steam of FC72 is supplied into
the condenser tube from a steam generator at a quality of 1.0.
Cooling water of 23ºC flows into the cold plate and heat is
exchanged between the cold plate and the condenser tube.
Heat loss from the condenser tube is calculated the fluid flowrate and the temperature difference between inlet and exit of the
tube. The working fluid is condensed completely and turns toliquid at the exit of condenser tube. Heat gain of the cold plateis also calculated by water flow rate and temperature difference
between inlet and exit of the cold plate.

－60－5. Results of qualification test for EM
Qualification test for the engineering model of TPF test loop
was already performed. Results and evaluations for the
performance of condenser will be presented in detail at theconference.

6. Conclusion
Fig.5 Ground test loop of condenser system
Liquid subcooling at the condenser tube exit is shown for theflow rate of cooling water in the cold plate in Fig.6.
According to the test results, the flow rate of test fluid, FC72, isgiven as 0.25kg/min in the present experiment on boiling for the
maximum heat transport of 400W. Here, the subcooling of test
fluid is 28K at the condenser tube exit for the flow rate ofcooling water of 45kg/h (0.75L/min), and this satisfies
sufficiently the requirements of ISS experiment. Pre-heating
may need at the entry of boiling test section to keep the liquid
subcooling of 10K at the tube exit. For the higher fluid flow
rate, 0.51kg/min and 0.76kg/min for example, it is unable tocondense completely in the condenser tube. So, the dry qualityof the test fluid is estimated 0.46 and 0.20 at the tube inlet toflow out as liquid from the condenser tube, respectively, as
shown in Fig.6.

Thermal design and evaluation test on condenser for TPF;
ISS Boiling Flow Experiment were carried out. Results are
summarized as follows;(1) Arithmetic thermal model for condenser on flat type coldplate was created.
By this analytical model, thespecification of condenser which satisfies the requirementsof ISS experiments, that is, 10K in outlet sub-cool
temperature could be determined.

(2) Ground based experiment for BBM condenser shows thatheat of 400W was transported to the cold plate from thecondenser tube at 45kg/h of cooling water flow. The
liquid subcooling of FC72 was higher than 10K at the exitof condenser tube.

(3) Results of BBM and EM tests proved that the present
condenser satisfied
experimental system.

therequirements

in

the

TPF

Acknowledgement
The authors express appreciation for the support of TPF
project by JAMSS, JSF, and for the contribution by Prof.
Kiyosumi Fujii in Nara Institute of Science and Technology
moved from JAXA.

References
1)

Krotiuk W. J., Thermal-hydraulics for Space Power,
Propulsion、and Thermal Management System Design,Vol. 122, Progress in Astronautics and Aeronautics, AIAA,
1990.

Fig.6 Liquid subcooling of FC72 at exit of condenser tube

－61－

－62－