Experimental Study On The Formation And Rising Characteristics Of Bubble In Solid-Liquid Suspension

Gas-liquid-solid three-phase flow is widely found in energy,chemical,environmental and other fields,such as wet dusting in impact water bath dust,bubble decontamination in sewage treatment,gas injection in metal smelting,froth flotation in mineral separation,and fluidized process in the three-phase fluidized bed,etc.This involves a lot of fluid dynamics behavior of bubbles.The formation and rising behavior of bubbles in the solid-liquid suspension system directly affect the efficiency of heat and mass transfer in related industrial equipment and industrial processes.It is important to investigate the behavior of bubbles in the solid-liquid suspension.Therefore,we taken the bubbles as the research object and revealed the formation and rising characteristic of bubbles in the solid-liquid suspension through experiment.This paper studied the influence of variable factors such as particle concentration,particle size,intake pipe diameter,surfactant and its concentration on the shape,size,formation velocity,movement velocity,rising trajectory,rising order of bubbles.Firstly,we built a visual experiment platform for observing the behavior of the bubbles in the solid-liquid suspension and used a high-speed camera to capture the process of formation and rising of the bubbles in the solid-liquid suspension.This paper studied the influence of variable factors such as particle concentration,particle size,intake pipe diameter,surfactant and its concentration on the shape,detachment size and formation frequency of the bubbles in the formation stage of bubbles at the normal temperature and pressure.We obtained the various rule of the evolution process of the bubble formation shape,the detachment diameter of bubbles and the formation frequency of bubbles with the intake flow rate.The research found that bubbles mainly bears an approximately spherical shape from formation to complete detachment from the nozzle of the bubbles.Their shape is closest to the regular spherical when the bubbles completely detach from the nozzle.The time from bubbles formation to detachment increases with the addition of particle concentration and intake pipe diameter,and it shortens with the addition of the surfactant concentration.The bubble detachment diameter and bubble formation frequency increase with the addition of intake flow rate.The influence of intake flow rate on bubble detachment size and bubble formation frequency gradually dominates.The bubble detachment diameter increases with the addition of particle concentration and intake pipe diameter,and it decreases with the addition of particle size.On the contrary,the bubble formation frequency decreases with the addition of particle concentration and intake pipe diameter,and it increases with the addition of particle size.The effect of surfactant in reducing the bubble detachment diameter increases with the increase of particle concentration,intake pipe diameter and surfactant concentration,and decreases with the increase of particle size.Its effect in accelerating bubble formation increases with the increase of particle size and surfactant concentration,and decreases with the increase of particle concentration and intake pipe diameter.Secondly,based on the above experiments,this paper made experimental observation and data analysis on the rising process of the bubbles in the solid-liquid suspension.This paper studied the influence of variable factors such as particle concentration,particle size,intake pipe diameter,surfactant and its concentration on the shape,size,motion velocity,rising trajectory,rising order of bubbles in the rising stage were studied at the normal temperature and pressure.This paper obtained the various rule of the evolution process of the bubble rising shape,bubble aspect ratio,bubble equivalent diameter,bubble vertical velocity,bubble horizontal velocity,bubble rising trajectory,bubble horizontal migration,and the vertical distance of adjacent bubbles with time.The research found that the bubbles evolve from approximately spherical shape to the cap shape and then to the flat shape,and finally to the ellipsoidal shape or irregular shape after they detach from the nozzle.Reducing the particle concentration and the intake pipe diameter can effectively reduce the variation range of the aspect ratio of bubbles,weaken the fluctuation of the bubble size,and make the shape and size of the rising bubble more stable.The bubble vertical velocity presents a change law that first increases and then remains constant with time when the surfactant is not added,and it presents a change law that first increases,then decreases,and remains constant finally with time when the surfactant is added.The variation rule of bubble vertical velocity with time is different with and without surfactant.With the addition of particle concentration,particle size and intake pipe diameter,the bubble horizontal migration decreases gradually.The bubble rising trajectory changes from S-shape to straight.The regularity and stability of bubble trajectory have also been enhanced.The bubbles gradually tend to be disorderly and chaotic in the rising process of bubbles.Reducing the particle concentration and particle size,and adding the intake pipe diameter can effectively enhance the bubble rising order.Surfactant reduces the bubble size and the bubble motion velocity,inhibits the bubble shape transformation and the bubble horizontal migration,and enhances the regularity of bubble rising trajectory gradually increase with the increase of its concentration.In comparison,the ability to reduce the bubble size and the bubble motion velocity,inhibit the bubble shape transformation and the bubble horizontal migration,and enhance the regularity of bubble trajectory of1-Pentanol,PEG 200 and MIBC is weakened in turn.