Numerical Simulation of a Single Bubble Passing Through a Circular Pipe with Change of Cross-Section

The numerical simulation of the behavior of a single bubble passing through a circular pipe with the change of cross-section has been carried out by the C-CUP method coupled with CSF model and Level-set method. This method can deal with both incompressible and compressible two-phase flows including surface tension effect. The present calculation succeeds in satisfying the mass-conservation law for the compressible flow in a bubble in remarkably good accuracy. The results present how the shape of a bubble is deformed and the pressure changes when it passes in the parts of a sudden expansion and a throal of a pipe flow at different values of Re and We numbers. It is also shown that some vortex-rings are formed in a wake of a bubble through a sudden expansion part of a pipe at the high Reynolds number of 500.