Dispersed multiphase flows

Most dispersed multiphase flows are inherently transient. As a consequence realistic simulations should be performed time-dependently and in full three dimensions. The solution of 3D transient models is unfortunately computationally time consuming and very demanding, both in terms of CPU-time and memory requirements. This severely reduces the ability to perform long time simulations to obtain reasonable statistics, which are needed for proper analysis of the reactor performance. For example the simulation of two-phase bubbly flow in a lab-scale bubble column, modelled with 650,000 computational grid-cells and 100,000 bubbles would take about 2 years on a state-of-the-art PC. In order to enable computationally expensive calculation, the strategy of parallelizing CFD codes has received extensive attention. By solving a problem in parallel not only the time required to solve the problem can be reduced significantly also the problem size that can be handled is increased since the memory requirement can be distributed.