A Numerical Simulation Study on Bubble Size Distribution in a Variable Diameter Pipeline based on CFD-PBM

This study aims to investigate the characteristics of bubble size distribution within a variable diameter pipeline. The pipeline is divided into five main sections: inlet section, contraction section, intermediate section, expansion section, and outlet section. A combination of numerical simulation and computational fluid dynamics (CFD) is employed to understand the impact of different pipe geometries on bubble behavior. This paper uses a set of boundary conditions and methods which are proven correct from an existing study for simulation. In the FLUENT 19.0 software, the Eulerian two-phase flow model combined with the standard $k-\varepsilon$ turbulence model is used to simulate the bubble size distribution within a pipe and the results were compared across different numerical methods: CM, QMOM, EQMOM, CQMOM, and ECQMOM. The combination is based on the inner mechanism in CFD solver. The significance of this study lies in its contribution to the common variable diameter pipeline systems in industrial processes. A deeper understanding of bubble dynamics is crucial for optimizing design and operation. This work not only provides new theoretical guidance for gas-liquid two-phase flow but also serves as a practical guide for chemical, petroleum, and other fields involving multiphase flow.