Theoretical Analysis And Experimental Research On The Airlift With Motion Characteristics Of Bubble Phase

The airlift system used in borehole hydraulic jet miming is widely used in underground mineral mining,oceanic mineral resources exploitation and sludge clearing in river or harbor.Traditional pump cannot play effectively under complicated condition,so the airlift system with functions of traditional pump and jet pump is put forward.The airlift system is researched in this paper,motion image sequences of bubbles phase in riser are collected by high speed digital imaging system,the target in image is tracked through high-speed analysis method,then sports phenomenon of bubbles phase in the process of rising is analyzed.In the present project,the influence mechanism and effect rule of the volumetric flow rate of air on the flow pattern characteristics are revealed based on the bubble dynamics theory and high-speed photography technology,then the criteria and construction method of the three-phase flow pattern map are further proposed,and the internal flow mechanism of three-phase flow is understated thoroughly.The study on key parameters in the formed process of bubbles shows that the influence of volumetric flow rate of air to the formed volume of bubbles is mainly divided into two stages: during low volumetric flow rate of air,the formed volume of bubbles has nothing to do with the volumetric flow rate of air;during high volumetric flow rate of air,the formed volume of bubbles increase faster with the change of volumetric flow rate of air.Bubbles generating frequency increase gradually with the growing of volumetric flow rate of air,then it becomes slowly.In the same flow section,bubble phase flows up and down periodically with time changing,which rising period is three to five times of falling period,the speed curve has obvious oscillation features.Bubbles rise from linear to zigzag: during low volumetric flow rate of air,the bubble moves gently with a smooth trajectory curve;when the volumetric flow rate of air increases,bubbles rise in a spiral process with the radial wave intensify.The study on flow structure in riser based on high-speed video technology shows that under different volumetric flow rate of air gas-liquid tow-phase and gas-liquid-solid three-phase appear alternately.Based on bubble-phase flow cycle,distribution in riser and mixed phase,mixing flow pattern in tube is divided into five types: slug flow,churn flow,bubble flow,particle-bubble flow and fiber-annular flow;among them,the bubble flow changes into particle-bubble flow after full developing,which is the optimal flow pattern to achieve particles lifting.