The effect of three-phase contact line pinning during the passage of an isolated bubble through a confining pore

The change in the internal pressure of an isolated dispersed phase passing through a confined geometry can be determined by tracking its deformation. While some research has been carried out on the motion of the dispersed phase, these have mostly focused on the calculation of the critical pressure required for the phase to enter the confined geometry and did not account for the variation of pressure across the phase as it passes through a confined geometry. In the current study, an algorithm based on the shadowgraph method was developed to evaluate the instantaneous change in the pressure of an isolated bubble passing through a confined geometry. The result of the study showed that the pressure across the bubble varies at different locations along the pore. The critical pressure was determined by detecting the change in pressure introduced at the entrance of the pore geometry. The results showed that the critical pressure increases as the size of the bubble increases. Phase pinning introduced a significant pressure change across the bubble as it exits the pore, resulting in significant deceleration of the bubble. The results of different sizes of bubbles passing through the same geometry showed that the pinning of the phase intensifies as the bubble size increases. The present study confirms the significance of the interaction of the solid interface and the dispersed phase on the motion of two immiscible flows in a confined geometry.