The deformation of moving slug bubbles and its influence on the bubble breakup dynamics in microchannel were studied.Three bubble morphologies were found in the experiment:slug,dumbbell and grenade shapes.The viscosit...The deformation of moving slug bubbles and its influence on the bubble breakup dynamics in microchannel were studied.Three bubble morphologies were found in the experiment:slug,dumbbell and grenade shapes.The viscosity effect of continuous phase aggravates the velocity difference between the fluid near the wall and the bubble,resulting in that the continuous phase near the bubble head flows towards and squeezes the bubble tail,which causes the deformation of bubbles.Moreover,the experimental results show that the deformation of bubbles could significa ntly prolo ng the bubble breakup period at the downstream Y-junction.There exists the critical capillary number Ca_(Cr )for the asymmetric breakup of grenade bubbles,Ca_(Cr )increases with the rise of flow rate and viscosity of the continuous phase.展开更多
The bubble formation dynamics and size manipulation in the slurry of polystyrene microspheres in the microfluidic T-junction were visually investigated by a high-speed camera.Based on the evolution of the bubble neck ...The bubble formation dynamics and size manipulation in the slurry of polystyrene microspheres in the microfluidic T-junction were visually investigated by a high-speed camera.Based on the evolution of the bubble neck with time,the formation process of bubbles is divided into three stages:filling,squeezing and pinch-off.The particle concentration has an obvious effect on the squeezing stage,while less impact on the filling and pinch-off stages.In the squeezing stage,the evolution of the dimensionless minimum neck width of bubbles with time could be described by a power-law relationship.The increase of the particle concentration or continuous phase flow rate could lead to the increase of body flow of the continuous phase and the enhancement of the squeezing force acted on the bubble neck,correspondingly,the power-law index a in the squeezing stage enlarges.Moreover,the bubble size increases with the increase of the gas phase flow rate and the decrease of the particle concentration and continuous phase flow rate.However,the effect of the particle concentration on the bubble size weakens with the increase of the continuous phase flow rate.In addition,a new prediction correlation of the bubble size for the slurry system in a T-shape microchannel was proposed with good prediction accuracy.展开更多
基金supported by the National Natural Science Foundation of China(21978197)the aid of Opening Project of State Key Laboratory of Chemical Engineering of China(SKLCh E-21Z03)。
文摘The deformation of moving slug bubbles and its influence on the bubble breakup dynamics in microchannel were studied.Three bubble morphologies were found in the experiment:slug,dumbbell and grenade shapes.The viscosity effect of continuous phase aggravates the velocity difference between the fluid near the wall and the bubble,resulting in that the continuous phase near the bubble head flows towards and squeezes the bubble tail,which causes the deformation of bubbles.Moreover,the experimental results show that the deformation of bubbles could significa ntly prolo ng the bubble breakup period at the downstream Y-junction.There exists the critical capillary number Ca_(Cr )for the asymmetric breakup of grenade bubbles,Ca_(Cr )increases with the rise of flow rate and viscosity of the continuous phase.
基金supported by the National Natural Science Foundation of China(21978197 and 21776200)。
文摘The bubble formation dynamics and size manipulation in the slurry of polystyrene microspheres in the microfluidic T-junction were visually investigated by a high-speed camera.Based on the evolution of the bubble neck with time,the formation process of bubbles is divided into three stages:filling,squeezing and pinch-off.The particle concentration has an obvious effect on the squeezing stage,while less impact on the filling and pinch-off stages.In the squeezing stage,the evolution of the dimensionless minimum neck width of bubbles with time could be described by a power-law relationship.The increase of the particle concentration or continuous phase flow rate could lead to the increase of body flow of the continuous phase and the enhancement of the squeezing force acted on the bubble neck,correspondingly,the power-law index a in the squeezing stage enlarges.Moreover,the bubble size increases with the increase of the gas phase flow rate and the decrease of the particle concentration and continuous phase flow rate.However,the effect of the particle concentration on the bubble size weakens with the increase of the continuous phase flow rate.In addition,a new prediction correlation of the bubble size for the slurry system in a T-shape microchannel was proposed with good prediction accuracy.
