CRITICAL PARAMETERS OF THE JAMIN EFFECT IN A CAPILLARY TUBE WITH A CONTRACTED CROSS SECTION
The Jamin effect acting as a flow resistance induced by bubbles or droplets, plays a critical role in the recovery of oils by water flooding, which is caused by the hysteresis of contact angle and contraction of capillary tube. In this study, we performed a comprehensive investigation on the mechanism of Jamin effect. The whole process of a bubble passing through the capillary tube is probed, where the bubble morphology and velocity based on the experiment and numerical simulation agree very well. The numerical result shows that, only the driving pressure exceeds the critical value, can the Jamin effect be overcome; and otherwise, the bubble would be pinned at the contraction. The dimensional analysis gives the relationship between the critical pressure and various parameters in the system. Finally, several simple and convenient empirical formulas are presented, which are very useful in some engineering areas. These findings can strengthen our understanding on the Jamin effect, and provide some inspirations for exploiting oils and gases with high efficiency.