多孔質内におけるレイリーテイラー型密度差自然対流

抄録

Understanding of natural convection of miscible two phases in a porous medium is of great importance to issues of geological storage of carbon dioxide (CCS). We consider fingering instabilities between two miscible fluids of saltwater and freshwater in a porous medium. Plastic resin particles were packed in a tube with the inter diameter of 70 mm. Development of the fingering due to instabilities and natural convection between freshwater and saltwater in porous media have been imaged by means of micro-focused X-ray computer tomography (CT). At early stages of convective mixing, ripples appear on the contour surface of the concentration of sodium iodine and grow to be fingers which extend vertically downwards with time. The dispersion strongly impacts on the reduction in the onset time as well as the enhanced mass transport. Finally, we discussed about the effect of the thickness of the initial diffusion layer on the structure of fingering.