油水气三相流的流型及泡状流向弹状流的转变

油水气多相混输是海上油气田开发中赖以取得重大经济效益的技术,其流动特性的准确计算是管线设计及安全、经济运行的重要依据.首先,通过实验确定出了油水两相混合物由油包水(W/O)向水包油型(O/W)的转变发生在含水率约为0.45时.垂直下降管内油水气三相流的流型基本上可以划分为油包水和水包油型的泡状流、弹状流及环状流.通过对垂直下降管内气泡碰撞、合并机理的分析建立了油水气三相流动过程中泡状流与弹状流间的转变界限的计算式,该转变发生的临界截面含气率约为0.35,计算结果与实验值的平均误差为11%.泡状流向弹状流的转变主要取决于折算气速和折算液速的大小,含水率对转变界限的影响较弱.

Flow patterns of oil-water-gas three-phase downward flow and transition from bubble flow to slug flow

The accurate calculation of the flow characteristics of oil water gas mixed transportation is an important basis of pipeline design and safe and economic running. The flow patterns of oil water gas three phase flow are classified into bubble flow, slug flow and annular flow. The experimental results show that the phase transition of oil water mixture flow from the state of water in oil (W/O) to the state of oil in water (O/W) occurs at the water cut of 0.45. By analyzing the mechanism of bubble collision and coalescence, a method is presented to predict the flow pattern transition from bubble flow to slug flow of oil water gas three phase downward flow, the error between the result calculated by the method and the experimental data is 11%. Such transition takes place at the void fraction of 0.35. It is mainly influenced by superficial gas and liquid velocities, while the effect of water cut on it is a little.