15 特集 国際宇宙ステーション日本実験棟 きぼう における流体実験 * Space Experiment on the Instability of Marangoni Convection in Liquid Bridge Koichi NISHINO, Department of Mechanical Engineering, Yokohama National University 1 thermocapillary convection Fig.1 T T =T h -T c T h T c T H mm Rayleigh H= D D 240-8501 79-5 E-mail: nish@ynu.ac.jp Fig. 2 1) Pr Pr International Space Station: ISS Maragoni Experiment in Space (MEIS) 2012 5 2008 Fig. 1 Schematic diagram of Marangoni convection in a liquid bridge
16 Fig. 2 The history of the previous microgravity experiments on the Marangoni convection in liquid bridges (sounding rocket experiments: TEXUS, TR-1A, MAXUS, space shuttle experiments: SL, D2, SPACEHAB, International Space Station experiments: KIBO) 8 10 2009 7 8 MEIS-1 MEIS-2 2 MEIS Fluid Physics Experiment Facility: FPEF Table 1 30mm 50mm 62.5mm 90 MEIS-1 2 5cSt Table 2 67 Fig. 2 Kawamura (2008) Nishino (2009) Table 1 Primary specifications of FPEF Functions Items and Methods Specifications Fluid supply Argon gas 20 NL/min at 88.2 to 101.3 kpa Cooling water 8.5 kg/h with T inlet =16-23 C and T outlet 43 C Test fluid 5 cst silicone oil Liquid bridge formation Tracers Metal-coated polymer particles 30 or 180µm in dia. Disk diameter, D 30 and 50 mm Length of LB, H up to 62.5 mm Temperature control Heated disk temp. maximum 90 C Cooled disk temp. minimum 5 C 3-D flow field observation Imaging Three B/W CCD cameras with 768 494 pixels Illumination Strobe lighting at 60 Hz Side-view observation Imaging One color CCD camera with 768 494 pixels Illumination Strobe lighting at 60 Hz Surface temperature Wavelength sensitivity of 8-14µm Infrared imager measurement temperature range of 0-100 C One color CCD camera 768 494 pixels Surface velocity Photochromic method N visualization 2 -gas laser for excitation Diode laser for background illumination
17 Table 2 Physical properties of 5cSt silicone oil density ( ) [kg/m 3 ] 915 kinematic viscosity ( ) [m 2 /s] 5 10-6 thermal conductivity ( ) [W/(m K)] 0.12 Prandtl number (Pr) 67.0 thermal expansion coeff. ( ) [1/K] 1.09 10-3 surface tension at 25 C ( ) [N/m] 19.7 10-3 temp. coeff. of ( T ) [N/(m K)] #1: -6.58 10-5 #2: -6.23 10-5 #1: MEIS-1, #2: MEIS-2 FPEF Fig. 3 3 IR 30 m MEIS-1 180 m MEIS-2 MEIS-2 TNSB 0.01-0.05wt% ISS g-jitter 0.3Hz Fig. 4 g-jitter 21:30GMT g-jitter 23:00 MEIS 23:00 06:00 Fig. 5 1 21:30 ISS LOS Fig. 5 00:45 37.5mm 05:00 20 4 30 3 D=30mm H=3 60mm T c Fig. 6 Ar=H/D T c MEIS Vr=0.95 Vr=()/( D 2 H/4)MEIS Ar T c MEIS-1 MEIS-2 1 Ar=0.75 MEIS Ar 0.75 Fig. 3 Schematic of the measurement apparatuses installed in FPEF and a photo of the mission part of FPEF (upper right)
18 Fig. 4 Time traces of g-jitter signals measured on KIBO Fig. 5 Typical procedures for each experimental run in MEIS T c Ma c Ma c T c T H (1) T T ( ) ( ) 2 h c Fig. 7 Ma c H H<6mm Ma c =6 10 3 3 10 4 H Ma c Monti 5cSt D=30, 45, 60mm 2) Ma c MEIS H Ma c 2 10 4 5 10 4 Monti D Ma c MEIS Ma c Fig. 8 F Ar F 2 2 fh (2) Fig. 6 Critical temperature difference plotted as a function Ar f MEIS Ar=1.25 F
19 Fig. 7 Comparison of Ma c with previous studies Ar m Fig. 9 Ar=0.23 m=3 Ar=0.23 0.32 0.46 m=3 2 1 m Ar Fig. 10 Ar=0.1 0.5 Ar m Ar 0.5 m=1 Ar m 1 MEIS Ar m<1 Ar=1.25 m=1 MEIS Ar=1.5 40 30 F 20 10 Ermakov MEIS-1 MEIS-2 0 0.5 1.0 1.5 2.0 2.5 Ar Fig. 8 Non-dimensional oscillation frequency plotted as a function of Ar + 3) MEIS Ma c MEIS Fig. 10 Relation between azimuthal mode number of oscillation and Ar Fig. 9 Visualization of azimuthal mode number in oscillatory state
20 3 Fig. 11 Ar=1.5T=11.2 C =3.7 T c 3 30s 15s Fig. 11(b)) Fig. 12 Fig. 11 IR IR Fig. 12 4) 5) Fig. 11 Particle traces for Ar=1.5 and T=11.2 C 4 MEIS MEIS 2012 5 30 50mm 62.5mm MEIS JAXA JAXA) ) MEIS (B) 21360101 Fig. 12 Particle trajectories and surface temperature: (a) side-view observation, (b) 3-D measurement, and (c) IR image 1) Kawamura, H., Nishino, K., Matsumoto, S. & Ueno, I.: Space experiment of Marangoni convection, keynote paper of the 14th International Heat Transfer Conference (IHTC14), August 8-13, 2010, Washington, DC, USA, IHTC14-23346. 2) Carotenuto, L., Castagnolo, D., Albanese, C. & Monti, R.: Instability of thermocapillary convection in liquid bridges, Phy. Fluids, 10-3 (1998), 555-565. 3) Ermakov, M., private communication (2010). 4) Schwabe, D.: Hydrothermal waves in a liquid bridge with aspect ratio near the Rayleigh limit under microgravity, Phys. Fluids, 17 (2005), 112104. 5) Xu, J-J. & Davis, S. H.: Convective thermocapillary instabilities in liquid bridges, Phys. Fluids, 27-5 (1984), 1102-1107.