Experimental study of bubble breakup process in non-Newtonian fluid in 3-D pore-throat microchannels

Abstract

Foam regeneration, an important step in foam profile control and foam flooding, is determined by the process of large dispersed mother bubbles breaking into small ones. The bubble behaviors in 3-D pore-throat microchannels were investigated in different polymer solutions by a high-speed digital camera. The initial bubble slug was generated through a co-flowing geometry and then flowed through a microfluidic constriction. Both breakup and non-breakup were observed at the operating conditions of Ca ranging from 0.000068 to 0.0067, and the breakup mechanisms can be divided into two different types: single bubble snap-off and multi-bubbles pinch-off. Emphases are given to the influences of pore-throat structures, capillary number and continuous phase viscoelasticity on the size variation of the daughter bubbles. The average daughter bubble size decreases with the increase of the pore-throat ratio or elasticity of solution. Furthermore, the change of the average size of daughter bubbles with capillary number could be scaled with a power law in breakup type Ι, while in breakup type ΙΙ, the mother bubble size becomes another decisive factor.