Dynamic capillary fringes - a multidisciplinary approach

点击翻译按钮获取中文摘要

The capillary fringe is characterized by the fluctuating water table evoking the dynamic formation and dissolution of trapped gas. Due to phase discontinuities flow and transport across this interface cannot be described by classical theory. In this sub-project we want to (I) experimentally explore the dynamics of phase saturation during water table fluctuations at a high spatial (0.01 mm) and high temporal (1 s) resolution using X-ray radiography, (ii) investigate the formation and dissolution of a residual gas phase under transient forcing, and (iii) study incoherent gas transport and the extent to which it may be represented by travel time distributions and effective continuum properties. The experiments will be run in Hele- Shaw cells corresponding to the other SPs. The continuum scale analysis will be complemented by optical measurements of the dynamics of water-gas interfaces and the movement and size distribution of gas bubbles at the pore scale (resolution 0.01 mm). Using 3D X-ray tomography the structure of the pore geometry is obtained which provides the basis for pore scale modeling of the dissolution of gas bubbles (SP2). Moreover, the pore structure will be quantified in terms of pore size distribution, connectivity and pore-solid interface curvature. These measures are then used as input to an equivalent micro-model where the detailed multiphase dynamics can be explored. This will provide the experimental basis to relate structural properties, external forcing and fluid properties to effective properties observed in the central experimental facility of CP.