Eulerian two-phase flow with phase change:cavitation modelling
Problem description
Cavitating flow in a nozzle-like geometry. The
cavitation process is modelled using the barotropic cavitation model.
Physics and modelling
The behaviour of cavitating flow systems is
similar to those of choking compressible flows: after a certain level of
prescribed pressure drop over the test geometry, the mass flow rate
remains constant in spite of the increased pressure difference between
the inlet and the outlet. This phenomenon is caused by the fact that
the cavitation bubble controls the flow. In this case, the geometry
of the case is a rough approximation of a Diesel injector and the
cavitation is modelled using the barotropic equation of state. The flow
simulation will be repeated for a range of prescribed pressure drop
values, ranging from 5 to 100 bar. As the pressure drop increases, the
size of the cavitation bubble increases; once the cavitation zone covers
the complete flow intersection, the mass flow remains constant in spite
of the further increase in the pressure drop.
OpenFOAM solver
Customised version of interFoam, including the cavitation
phase-exchange terms.
Images and animations
The images presented below show the velocity
field and the isolines of the volume fraction of the liquid phase (red =
liquid; blue = gas). The top image is for a pressure drop of 50 bar and
the bottom image is for a drop of 100 bar.
