高黏体系中纳米颗粒稳定气泡的形变及破裂行为OA北大核心CSTPCD

A high-speed camera was used to study the morphology of nanoparticle-stabilized bubbles in the highly viscous fluid in the microchannel during the flow process and its impact on the bubble collapse at the downstream symmetrical Y-junction bifurcation.Three shapes of moving bubbles in the straight channel were observed:slug bubble,dumbbell bubble,and grenade bubble,and the bubble shape was mainly affected by the flow rate of the dispersed phase.The breakup flow pattern of the bubbles at the Y-junction is mainly breakup with partial blockage.The breakup period of bubbles adsorbing nanoparticles is larger than that of bubbles without nanoparticles,and the difference of their breakup period ΔTb shows three different rules.ΔTb is positive and positive correlation with Ca when Ca>0.042.There are two cases when Ca<0.042:ΔTb is positive and negative correlation with Ca;ΔTb is negative and positive correlation with Ca.In addition,the deformed bubbles show asymmetric rupture behavior at the Y-junction,and the asymmetry of their breakup is related to the degree of deformation of the bubbles.When Ca is larger than the critical capillary number CaCr,the reduction rate of diameter at the tail of the bubbles accelerates,which exacerbates the deformation of the bubbles and causes more significantly asymmetric breakups of the bubbles.The results show that the CaCr value of bubbles adsorbing nanoparticles is the same as that of bubbles in the particle-free system,but grenade bubbles adsorbing nanoparticles show a greater degree of deformation and more obvious breakup asymmetry.