 |
 |
 |
 |
 |
 |
 |
Many fluid flows in the applications of CFD to the chemical process industry involve fluids mixed together at the macroscopic level. These include, for example, mixtures of immiscible liquids; mixtures of liquids and gases, including droplets in a gas, and bubbles in a liquid; and solid particles carried by a liquid or a gas. All of these types of flows can be modeled using multiphase flow modeling.
The multiphase model in the ANSYS CFX solver calculates all of these types of flows by solving separate transport equations for velocity, temperature and mass fractions etc for each fluid, with interphase connections through drag, heat and mass transfer. In addition to the coupled solver for the velocity and pressure fields for single-phase flows, velocities of all phases and pressure are also solved together in a fully coupled manner to make the calculation of multiphase flows fast and robust.
In addition to the basic multiphase model, there are submodels for calculations of various types. These include the Multiple Size Group (MUSIG) model for carrying out population balance dynamics in a bubble column; the kinetic theory model of granular temperature for calculating fluidized beds; mass transfer models for cavitation and thermal phase change; and a homogeneous model with surface tension forces for calculating free surface flows.
Simulation of the multi-phase flow
through a submerged entry nozzle (SEN)
used in metals processing.
