Experimental and CFD Modelling of the Drift Flux in Two-phase Air-(non)Newtonian Slug-flow Pattern Flow Along Horizontal and Inclined Pipelines
Author | : Paula Daniela Pico Viviescas |
Publisher | : |
Total Pages | : |
Release | : 2018 |
ISBN-10 | : OCLC:1157919200 |
ISBN-13 | : |
Rating | : 4/5 (00 Downloads) |
Book excerpt: The present study analyzes the influence of the physical properties of Newtonian and non-Newtonian fluids, such as density, effective viscosity and surface tension, as well as operational parameters of the piping, such as diameter, length and inclination angle on the drift velocity for two-phase gas-liquid flow. This study comprises experimental and Computational Fluid Dynamic (CFD) approaches. The simulation model was calibrated through a mesh independence test, which considered experimental and literature data as benchmark, and was divided in three sections based on the viscosity of the fluid and the positioning of the pipeline. The results obtained through the CFD model showed good agreement with the experimental data gathered for the present study, keeping the experimental deviations under 30% for all cases. The relationship between the Froude number (Fr) and Viscosity number (Nvis) was studied and an inverse exponential pattern was found for all the parameters and fluids tested. Additionally, the relation observed between Fr and Nvis for a horizontal setting on Newtonian fluids had good resemblance with the models proposed in literature, predicting accurately a decreasing behavior of the drift velocity for increasing viscosity. The data gathered for all fluids on the drift velocity's behavior against operational parameters showed the influence of the governing forces for each case based on a dimensionless analysis using Etvos (Eo) and Reynolds (Re) numbers. For dominant capillary or viscous forces, the drift velocity changed with the variation of these parameters. However, it was found that for dominant inertial and gravitational forces, the drift velocity maintained a constant value regardless of the operational settings. Finally, it was observed that the rheological nature of the non-Newtonian fluids has a significant influence on the drift velocity's behavior, deviating its patterns from the Newtonian fluids as the effective viscosity changes.