Vergleich mathematischer Modelle zur Behandlung von Zweiphasenströmungen

Two-phase flows are one of the major topics in fluid dynamics, especially since the performance of computers is increasing. The physical models for treatment of gas-particle flows are discussed. One can divide the models in two groups. The first group contents the physical models based on continuum mechanics. This leads to the conservation equations for mass, momentum and energy for both phases. In this case we can divide once again the models in a total eulerian form and in a mixed form were the particles are descripted in lagrangian and the gas in eulerian coordinates. The second group of models comes from the statistical mechanics. The particles are considered as molecules. This leads to a kinetic theory for the particles. The big advantage of this method is, it includs interparticle collisions. It was found that there exists no universell physical model to descript gas-particle flows. All models have advantages and disadvantages. One has to be clear which kind of problems has to be solved. After that one can choose the physical model and the numerical method to solve the problem.