A study on the bubble accumulation and coalescence phenomena in liquid and gas two-phase flow

在这项研究中，在大直径管道中的液-气两相流中的气泡聚集和合并现象进行了局部测量的流动参数，如空隙率，界面面积浓度，气泡尺寸，气体速度，液体速度和湍流强度，通过使用本地传感器技术，如光学多传感器探头和热，并建立了局部流动参数数据库。实验结果表明，这种现象是由于管道尺寸的大气泡的形成和发展造成的。在此基础上，建立了适用于泡状流向弹状流转变的漂移通量模型。采用一维双流体模型，并在其界面阻力模型中加入了新发展的漂移通量模型，对气泡的聚集和聚并现象进行了数值分析。数值计算很好地预测了本实验中观察到的气泡聚集和聚并现象。

In this study, local measurements for the bubble accumulation and coalescence phenomena in a liquid-gas two-phase flow in a large diameter pipe were performed on flow parameters, such as void fraction, interfacial area concentration, bubble size, gas velocity, liquid velocity and turbulence intensity by using the local sensor techniques such as optical multi-sensor probes and hot-film probes and a database for the local flow parameters has been established. The experiment results show that the phenomenon can be attributed to the formation and development of large bubbles of pipe size. Based on the database, a drift flux model was newly developed for the flow evolving from bubbly to slug flows. The bubble accumulation and coalescence phenomena were numerically analyzed by using the one-dimensional two-fluid model with its interfacial drag model modified by including the present newly developed drift flux model. The numerical calculation predicted well the bubble accumulation and coalescence phenomena observed in the present experiments.