Abstract
Multiphase fluid flow is an active field of research in numerous branches of science and technology. An interesting subset of multiphase flow problems involves the dispersion of one phase into another in the form of many small bubbles or droplets, and their subsequent separation back into bulk phases after this has occurred. Phase dispersion may be a desirable effect, for example in the production of emulsions of otherwise immiscible liquids or to increase interfacial surface area for chemical reactions, or an undesirable one, for example in the intermixing of waste and product phases during processing or the generation of foams preventing gas-liquid decoupling. The present paper describes a computational fluid dynamics method based on the multiple marker front-capturing algorithm – itself an extension of the volume-of-fluids method for multiphase flow – which is capable of scaling to mesoscale systems involving thousands of droplets or bubbles. The method includes sub-grid models for solution of the Reynolds equation to account for thin film dynamics and rupture. The method is demonstrated with an implementation in the OpenFOAM® computational mechanics framework. Comparisons against empirical data are presented, together with a performance benchmarking study and example applications.
Highlights
The problem of separating two immiscible fluids after they have become mixed arises in many branches of process engineering
In the new approach presented here, which we refer to as the dynamic multiple marker (DMM) method, this is addressed by dynamically reassigning particles of the dispersed phase to a small number of marker phases such that no adjacent particles use the same phase
In order to evaluate the performance of the DMM method against traditional multiphase approaches for resolved dispersed-phase problems, simulations were performed using a planar two-dimensional metallurgical system in which droplets of dense molten metal settle through a lighter molten slag continuum phase
Summary
The problem of separating two immiscible fluids after they have become mixed arises in many branches of process engineering. In the new approach presented here, which we refer to as the dynamic multiple marker (DMM) method, this is addressed by dynamically reassigning particles of the dispersed phase to a small number of marker phases such that no adjacent particles use the same phase This is achieved at each time step in a transient VOF calculation by identifying collections of mesh cells belonging to each discrete particle of the dispersed phase, tagging pairs of particles which are in close proximity to one other, and using this information to generate a graph representing the pairwise contacts for the set of all particles in the simulation. The major algorithm components are described in more detail
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
