Development of Two-Phase Flow Loop Thermal Control System for Space Structure
-Boiling Two-phase Flow Experiments in International Space Station-
Purpose
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With the progress of space development, the increase in power consumption and heat transport distance becomes problems.
Space development will continue, and this problem might become even more serious. Therefore, Two-phase flow loop control system using latent heat of the coolant has been considered.
In this system, heat transfer using latent heat can reduce the circulating flow rate of the coolant for required cooling rate. and higher cooling heat transfer by boiling.
However, it is necessary for the design of the system to clarify heat transfer and flow characteristics of boiling vapor-liquid two-phase flows under microgravity.
In this study, boiling two-phase flow experiments had been successfully carried out under the stable microgravity condition in Japanese Experimental Module “KIBO” of International Space Station (ISS) as a JAXA project named TPF experiment.
Gas-liquid two-phase flow behaviors were observed in the adiabatic observation section with the channel diameter of 4 mm directly connected to a heating tube.
Research content
The experimental loop is a pump driven two-phase flow loop, in which the fluid pressure can be maintained around the cabin pressure by accumulators.
The experimental loop has two kinds of heating section in parallel, those are a copper heating tube and a transparent glass heating tube. Perfluorohexane whose boiling point is 57℃ was selected as the working fluid.
An adiabatic observation is placed just at the downstream of each heating section. The optical system for stereoscopic photography was applied in order to observe the three-dimensional interfacial structure.
The difference of the flow structure between normal and microgravity under
higher vapor quality or higher mass flux condition would be small because
inertia force would be dominant against gravity when the high velocity.
However, at high mass flux with low vapor quality, an unique flow pattern
as shown in the image was observed. Densely packed relatively small bubbles
were flowing continuously without coalescence. Especially, a few bubbles
existed in the same cross-section. Such flow pattern is caused by the loss
of buoyancy force, namely the loss of gravity.
Publications
H. Ohta, H. Asano, O. Kawanami, et al.
Development of Boiling and Two-Phase Flow Experiments on Board ISS (Research
Objectives and Concept of Experimental Setup), International Journal of
Microgravity Science and Application 33(1) (2016), 330102. https://doi.org/10.15011/ijmsa.33.330102
R. Imai, K. Suzuki, H. Kawasaki, H. Ohta, Y. Shinmoto, H. Asano, et al.
Development of Boiling and Two-Phase Flow Experiments on Board ISS (Condensation
Section), International Journal of Microgravity Science and Application
33(1) (2016), 330103. https://doi.org/10.15011/ijmsa.33.330103
T. Gomyo, H. Asano, H. Ohta, Y. Shinmoto, et al.
Development of Boiling and Two-Phase Flow Experiments on Board ISS (Void
Fraction Characteristics in the Observation Section just at the Downstream
of the Heating Section), International Journal of Microgravity Science
and Application 33(1) (2016), 330104. https://doi.org/10.15011/ijmsa.33.330104
T. Hirokawa, D. Yamamoto, D. Yamamoto, Y. Shinmoto, H. Ohta, H. Asano, et al.
Development of Boiling and Two-Phase Flow Experiments on Board ISS (Investigation
on Performance of Ground Model), International Journal of Microgravity
Science and Application 33(1) (2016), 330105. https://doi.org/10.15011/ijmsa.33.330105
K. Sawada, T. Kurimoto, A. Okamoto, S. Matsumoto, H. Takaoka, H. Kawasaki, M. Takayanagi, Y. Shinmoto, H. Asano, et al.
Development of Boiling and Two-phase Flow Experiments on Board ISS (Dissolved Air Effects on Subcooled Flow Boiling Characteristics),
International Journal of Microgravity Science and Application 33(1) (2016), 330106. https://doi.org/10.15011/ijmsa.33.330106
M. Okubo, O. Kawanami, K. Nakamoto, H. Asano, H. Ohta, et al.
Development of Boiling and Two-phase Flow Experiments on Board ISS (Temperature Data Derivation and Image Analysis of a Transparent Heated Short Tube in the Glass Heated Section),
International Journal of Microgravity Science and Application 33(1) (2016), 330107. https://doi.org/10.15011/ijmsa.33.330107
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