基于高速摄像技术的气力提升性能分析

中文摘要: 采用高速摄像系统对提升管内三相流运动状态进行拍摄，深入研究气-液-固三相流提升性能随运行参数变化的规律，并基于图像处理方法对管内流场结构和固相运动特征进行分析。结果表明：随气量值变化，提升管内流型呈周期变换，依次为稀疏型泡状流、密集型泡状流、泡状搅拌流、混合搅拌流、稀疏型泡状流，其中泡状搅拌流更利于固体颗粒的提升。相同气量值下，气力提升系统排固量、排液量和提升效率随淹没率的升高呈先增加后减小趋势；同工况下进气量对系统提升性能的影响大于淹没率，且存在最佳气量值使得系统提升效率最高；当气量值较低时，管内颗粒浓度低且多集中于管壁位置，随气量值增大颗粒向管中心运动，且此处颗粒运动速度和浓度值均较高。此外，随着进气量的变化，提升管内交替出现气-液两相流与气-液-固三相流，并且气量值的变化直接影响管内颗粒分布及其运动状态。与单颗粒相比，群颗粒作用下系统提升性能较高，且不同径向位置的颗粒速度并不对称于提升管中心线。
Abstract:The dynamic images of gas-liquid-solid three-phase flow in the riser were obtained by the high-speed camera system,the variation of the lifting performance of three-phase flow with operating parameters were studied,and the flow field structure and the movement characteristics of solid particles in the riser were analyzed based on the image processing method.The result showed that the periodic variation of flow pattern is formed in the riser,in turn,spare bubble flow-intensive bubble flow-bubble churn flow-mixed churn flow-spare bubble flow,in which the bubble churn flow is more conductive to lift solid particles.Under the same amount of air inlet,the discharged amount of solid,liquid and lifting-efficiency increases first and then decreases with the increase of submergence ratio.The effect of air inlet on the performance of system is higher than that of submergence under the same operating conditions.During the low flow rate of air,the particle concentration is low and most of it concentrate in the pipe wall.With the increase of air flow rate,the particles move to the core,and the particle concentration and the lifting velocity are more higher than other parts.In addition,the gas-liquid two-phase flow and gas-liquid-solid three-phase flow is appeared in turns in the riser with the change of air let,and the particle distribution and motion state also be affected by it.The system was proved a better performance,compared with the single particle,under the action of group particles.Particularly the velocity of particles in different radial positions are not equally distributed about the center line of the pipe.