二成分縞状スリット流動の形態

抄録

The ratio of widths R between two phases of a stationary stratified flow for which the phase interface is parallel to the side walls of a rectangular slit is calculated under the condition that the two phases give equal volume fluxes. For a combination of two Newtonian fluids, the width ratio Ris simply proportional to their viscosity ratio. If both components are of the power-law type, R is greater than the viscosity ratio and increases with the amount of shear-thinning (pseudo plasticity) of the higher viscosity component. For a combination of a Bingham fluid with a Newtonian fluid R decreases with increasing yield stress of the former.
Measurements of R were made on various combinations of polyvinyl alcohol (PVA) solutions and of suspensions of CaCO₃ in PVA solutions. In the former cases, the experimental values were in good agreement with the theoretical values for the power-law fluids. In the latter, R was primarily affected by the yield stress as predicted by the theory, but a correction was found to be necessary for the shear-thinning effect.