CFD simulation of the two-phase flow around an obstacle applying an inhomogeneous multiple bubble size class approach

In recent years in close cooperation with ANSYS/CFX a population balance model was developed to simulate multiphase flow with higher gas volume fraction. Several dispersed gaseous phases are modeled having a distinct velocity field. Bubble fragmentation and coalescence is simulated by decades of gaseous sub-size mass fractions, which are assigned to the few dispersed gaseous phases. This approach was called “inhomogeneous MUSIG model” and enables the simulation of bubble size dependent bubble forces.
The presentation reports the basic principles and the application of the model approach to simulate a TOPFLOW experiment, in which a complex three dimensional flow field was measured. A half moon shaped obstacle was arranged in the DN200 test section and the two phase flow field was analysed by a wire mesh sensor.
Applying this approach a more deep understanding of the flow structure is possible. To improve the quantitative accuracy further developments particularly of the models describing bubble fragmentation and coalescence are necessary.