A new transient model of multi-scale bubble migration and evolution during gas-liquid flow in pipelines

Abstract

This paper investigated the bubble migration and evolution during gas-liquid flow in oil-pipelines. Multi-scale bubbles migrated in the pipe while interacting with each other, causing coalescence and disintegration. The bubbles collided and coalesced, forming a new air pocket in the downward inclined pipe that blocked the transportation of both the gas and liquid phases. Consequently, the buoyance weakened the migration ability of the bubbles, which is known as re-coalescence. To investigate, a new transient model applied with the population balance model (PBM), and Eulerian-Lagrangian coupling scheme is proposed. The complex flow field was modeled using the Eulerian scheme, while the migration of the bubbles was designed in the Lagrangian mesh. Furthermore, the PBM was employed to describe the multi-scale bubble interaction and migration. Smooth particle hydrodynamics were applied to connect the bubble-dimension and pipe-dimension descriptions. Therefore, the bubble fraction could be described to predict the re-coalescence of air pockets. The required unknown model parameters were extracted from the published experimental data, while the simulation results corresponded well with the measured results. During the simulation, the effect of the liquid Froude number and pipe inclination on the size distribution of the multi-scale bubbles were investigated. The results indicated that an increase in the pipe inclination and liquid Froude number improved the bubble migration capacity, leading to a broader distribution of bubbles of all sizes. • A new transient modelfor bubble transportation and evolution in gas-liquid flow in the oil pipeline is proposed. • The migration abilities coupled with the bubble coalescence and breakup of different sizes of bubbles in the inclined pipe are analyzed. • The prediction of the transportation blockage based on bubble tracking and smooth particle hydrodynamics is introduced. • A new insight into the pipeline blockage from the bubble-dimension to the pipe-dimension is introduced. • Effects of pipe inclination, as well as liquid Froude number to the bubble size distribution in oil pipeline are analyzed.