基于丝网传感器的气水两相流流型转换测量

Flow Regimes Transition Measurement of Gas-water Two-Phase Flow Based on Wire-Mesh Sensor

两相流流型有助于两相流体结构与运动规律的研究,是开展气水两相流研究的基础。为了探究各种流型之间转换过程中的流体动力学现象,利用丝网传感器(Wire Mesh Sensor,WMS)通过对50 mm内径的垂直管道不同流动条件下各种流动形态的空隙率、气泡分布及其变化过程成像测量表明在水相表观流速不变,气相表观流速增加的条件下,从泡状流到弹状流过渡过程中,均匀分布的离散小气泡密度逐渐增加,管道中心气泡浓度逐渐高于管壁,管道中心小气泡开始碰撞聚合形成大气泡;随着水相表观流速减小,进一步增加气相表观流速,弹状大气泡破裂成若干不规则气泡,向下一个流型过渡。

Two-phase flow regime is very helpful for understanding flow structure and flow motion,which is the basis for the gas-water two-phase flow studies.In order to investigate the gas-water flow dynamics during the flow regimes transition,wire mesh sensor(WMS)is employed to measure the gas-water flow under different flow conditions in a vertical pipeline with 50mm internal diameter,where the void fraction,bubble distribution and flow regimes transition processes are measured and imaged.With the increase of superficial gas velocity at a constant superficial water velocity,the bubble flow is starting to transit to slug flow,where the disperse bubbles start merging and forming a slug bubble.Meanwhile,the concentration of uniform distributed disperse bubbles is gradually increasing and the bubble concentration at the pipeline center is higher than that at the pipeline boundary.With the further increase of superficial gas velocity and the decrease of superficial water velocity,the large slug bubble is broken into irregular bubbles,and the flow regime starts to forward into the next one.