CFD Modelling of Multiphase Systems

This section focuses on CFD modelling of multiphase systems. Following are some examples of multiphase systems  

1 Laminar Mixing in Stirred-Tank Reactor Numerical Study 

Two properties of chaotic flows make them very attractive for mixing in the laminar regime  

The former property means that two trajectories starting very close together will rapidly diverge from each other, and thereafter have totally different evolutions. Suppose x t) is a point on a streamline at time t, and consider a nearby point x t) + 8(f), where 8 is a small separation vector of an arbitrary initial length 8(0). In chaotic flows, the ratio 8(f)/8(0) known as the stretching of a fluid element grows as 

The computational domain has been modelled as three distinct volumes a large cylinder for the mixing tank impeller, blades and shaft and other volumes as inlet and outlet in some configurations. This allowed the mixing tank to be modelled with relatively coarse elements, while the smaller inlet/outlet pipes could have a much finer mesh applied as compared to the tank. If the domain had consisted of a single volume, a very large number of small elements would have been required to mesh it, as the mesh size would have to be chosen based on the size of the inlet/outlet pipes, impeller blade, shaft and tank wall. Meshing the three main volumes separately allows a dramatic reduction of the amount of 

---