TY - JOUR
T1 - Measurements of clathrate-hydrate film thickness using laser interferometry
AU - Ohmura, Ryo
AU - Kashiwazaki, Shigetoyo
AU - Mori, Yasuhiko H.
PY - 2000/9/15
Y1 - 2000/9/15
N2 - Using a laser interferometer having a resolution of approximately 1 μm, we directly measured the thicknesses of clathrate-hydrate films at the planar interface between a liquid hydrofluorocarbon, R-134a (CH2FCF3), and liquid water. The interferometer was mounted on a specially designed, pressure- and temperature-controlled cell filled with both liquids. After a hydrate film was formed with either pure water having no prior contact with R-134a or water presaturated with R-134a, we made a series of intermittent measurements until the film was aged up to 150 h. For hydrate films formed with pure water held at a large subcooling (approximately 7 K) below the triple (liquid-R-134a/hydrate/liquid-water) equilibrium temperature, the initial thickness was approximately 10 μm. This thickness was maintained for a few tens of hours; then it gradually increased, reaching approximately 30 μm 100 h after the film formed. With pure water at a smaller subcooling (≲2 K), the thickness of hydrate films was initially as large as approximately 80 μm; it rapidly decreased to 15-20 μm and then increased to 30-40 μm 150 h after the film formed. With presaturated water at small subcoolings (≲2 K), each hydrate film was a mosaic of polygonal hydrate crystal plates. Each plate was several millimeters wide and 20-170 μm thick. No measurement could be made with presaturated water at a large subcooling (≳6 K) because of sword-like hydrate crystals that have grown in crowds into the water phase from the hydrate film surface.
AB - Using a laser interferometer having a resolution of approximately 1 μm, we directly measured the thicknesses of clathrate-hydrate films at the planar interface between a liquid hydrofluorocarbon, R-134a (CH2FCF3), and liquid water. The interferometer was mounted on a specially designed, pressure- and temperature-controlled cell filled with both liquids. After a hydrate film was formed with either pure water having no prior contact with R-134a or water presaturated with R-134a, we made a series of intermittent measurements until the film was aged up to 150 h. For hydrate films formed with pure water held at a large subcooling (approximately 7 K) below the triple (liquid-R-134a/hydrate/liquid-water) equilibrium temperature, the initial thickness was approximately 10 μm. This thickness was maintained for a few tens of hours; then it gradually increased, reaching approximately 30 μm 100 h after the film formed. With pure water at a smaller subcooling (≲2 K), the thickness of hydrate films was initially as large as approximately 80 μm; it rapidly decreased to 15-20 μm and then increased to 30-40 μm 150 h after the film formed. With presaturated water at small subcoolings (≲2 K), each hydrate film was a mosaic of polygonal hydrate crystal plates. Each plate was several millimeters wide and 20-170 μm thick. No measurement could be made with presaturated water at a large subcooling (≳6 K) because of sword-like hydrate crystals that have grown in crowds into the water phase from the hydrate film surface.
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U2 - 10.1016/S0022-0248(00)00564-9
DO - 10.1016/S0022-0248(00)00564-9
M3 - Article
AN - SCOPUS:0034276052
VL - 218
SP - 372
EP - 380
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
SN - 0022-0248
IS - 2
ER -