3D numerical study of a single Taylor bubble rising along an inclined tube through Newtonian and non-Newtonian liquids

Slug flow is an important gas-liquid flow pattern characterized by large bullet-shaped bubbles (Taylor bubbles) and is widely found in industrial and natural applications. The hydrodynamics are complex and depend on tube dimensions and orientation, operating conditions, and physical properties. Therefore, detailed knowledge of slug flow hydrodynamics can provide insight into a robust and safe intensification of industrial processes in several fields.This work fills a gap in knowledge by producing new information about slug flow in inclined tubes. For the first time with complete conservative equations, CFD tools are applied to simulate 3D systems composed of isolated Taylor bubbles rising through stagnant liquids in tubes with different inclinations. This study addresses Newtonian liquids with different viscosities and non-Newtonian liquids with shear-thickening behavior.The effects of geometric and physical properties are assessed, and descriptions of bubble shape and velocity, liquid film thickness, velocity profiles around the bubble, and liquid wake characteristics are presented and discussed.The results allow to conclude that the tube inclination deeply impacts the flow by changing the bubble po-sition, velocity, shape, and the way the liquid flows around it. The inclination effect coupled with different liquid rheology introduced even more complexity to the hydrodynamic features.