Influence of sinusoidal flow pulsations of the dispersed phase on the flow characteristics of immiscible viscous liquids in a T-type microchannel

The influence of sinusoidal pulsations of the flow rate of the dispersed phase on the flow characteristics of immiscible high-viscosity liquids in a T-shaped microchannel has been studied. The flow regimes in the unperturbed flow and in the flow subjected to external perturbations with different frequencies and amplitudes were visualized. A dimensionless complex is proposed that describes the transition from parallel to plug flow due to external pulsations for a fixed capillarity number of the carrier phase. The application of perturbations to the plug flow regime is found to lead to flow stabilization and to a reduction in the spread of values of the generated plugs at a frequency equal to the natural frequency of plug separation in the unperturbed flow. The average length of the plugs and the spread of its values are shown to increase with decreasing perturbation frequency.