MultiFlow
MultiFlow is a fully coupled 2 and 3 dimensional viscous Multiphase Flowsolver which can be employed to solve different models applicable to multiphase flows. Its core is a fully coupled finite volume Computational Fluid Dynamics (CFD) solver for various sets of governing equations.
MultiFlow employs momentum weighted interpolation to determine analytical expressions for the cell face velocities which are employed in the multiphase continuity equation in a collocated variable arrangement. A special approach is adopted for the momentum
weighted interpolation to handle large source terms, volume fractions, and gradients of these. The resulting linearized equations are solved in a fully coupled manner.
This approach has been employed for a number of multiphase flow models:
In the Euler-Lagrangian module, the gas phase is treated as continuous, and the particles are modelled individually by a discrete element model (DEM) or discrete particle model (DPM). Various drag models, LES models are supported. Moreover, modelling non-spherical particles is supported.
The VOF module supports the simulation of two immiscible fluids with varying density and viscosity. Various schemes are supported for both Cartesian meshes, such as Lagrangian PLIC, and non-Cartesian meshes, such as Compressive methods.
In the immersed boundary method, the flow surrounding boundaries can be predicted. The boundaries, which are immersed in the flow, can take any shape. Flow surrounding particles can be resolved and the drag on the individual bodies can be determined. Bodies can also collide in the flow.
Most industrial multiphase flow problems are treated with the Eulerian-Eulerian multiphase model, where all phases are treated as continuous, interpenetrating continua. Several closure models for various types of fluids or solids are available. Work for this model is currently under construction.