Modelling of Bubbly Flows in CFD Using the Intersection Marker Front-Tracking Method

Download files
Access & Terms of Use
open access
Copyright: Ho, Mark
Altmetric
Abstract
Most computational fluid dynamic (CFD) codes use the Finite Volume Method (FVM) to spatially discretise the computational domain. FVM works well with single-phase flow simulations but two-phase flow simulations are more challenging because of the need to track the interface that traverse and deforms within the three dimensional (3D) Eulerian grid. To attain a higher accuracy in two-phase flow CFD calculations, the Intersection Marker (ISM) method was developed. The ISM method is a hybrid Lagrangian-Eulerian Front Tracking algorithm which can model an arbitrary 3D surface within an array of cubic control-volumes. Implemented in Fortran95, the ISM method possesses cell-by-cell remeshing capability that is volume conservative and suitable for the tracking of interface deformation in transient two-phase CFD simulations. The ISM tracking algorithm was benchmarked in a series of surface deformation tests. The most challenging test deformed a spherical volume in an incompressible velocity field of non-linear vorticity. The spherical shape was then recovered by reversing the velocity field to attain the original volume and shape. To demonstrate the feasibility of the ISM algorithm for two phase flow simulations, the ISM algorithm was coupled to an in-house CFD code which was modified to simulate two phase flows using a single fluid formulation. The constitutional equations incorporated terms of variable density and viscosity. Also body-force source terms were included in the momentum equation to account for surface tension and buoyancy effects. The bubble surface was tracked by the ISM interface tracking algorithm which accurately passed surface data to the flow solver to calculate local variations in density and viscosity, buoyancy forces and surface tension forces. At each timestep, the surface mesh was advanced to new locations as dictated by the calculated velocity field. Within each control volume, the interface was locally remeshed to re-normalise the number of surface tracking points per control volume and to enforce the local volume conservation criteria within each cell. The performance of two phase flow simulations was benchmarked against experimental data for a bubble rising in quiescent fluid. A variety of bubble sizes were tested to demonstrate the accuracy of the ISM interface tracking method for simulating bubble rising problems. The results attained were in close agreement with experimental observations.
Persistent link to this record
Link to Publisher Version
Link to Open Access Version
Additional Link
Author(s)
Ho, Mark
Supervisor(s)
Timchenko, Victoria
Reizes, John Arthur
Yeoh, Guan Heng
Creator(s)
Editor(s)
Translator(s)
Curator(s)
Designer(s)
Arranger(s)
Composer(s)
Recordist(s)
Conference Proceedings Editor(s)
Other Contributor(s)
Corporate/Industry Contributor(s)
Publication Year
2016
Resource Type
Thesis
Degree Type
PhD Doctorate
UNSW Faculty
Files
download public version.pdf 5.3 MB Adobe Portable Document Format
Related dataset(s)