Multiphase supersonic flow simulation for geothermal applications

Multiphase simulations pose a great challenge, because one has to capture the big difference of density and the correct momentum transfer between a liquid and a gaseous phase. With the addition of supersonic velocities and high pressure regions, the simulation has to be able to capture the difference in compressibility, too. In order to deal with these issues a CFD solver was implemented in the open-source CFD-tool OpenFOAM.

The developed solver in OpenFOAM is capable of simulating the geometry and it can be seen that the simulated device is capable of creating a specific kinetic energy of the accelerated water so that the performance is comparable to existing watercutting tools. Some other effects like phase change could change the results in second order, however processes, which dominate the simulated time scale, are considered in the model and the major scales of the flow are depicted correctly. Refinement of the model could include closer consideration of turbulence and phase change.