Interface capturing in compressible two-phase flows with non-equilibrium models*

The applications of compressible multiphase flows in aerospace applications are numerous. The target is to develop a robust framework to model two phases and preserve interfaces in a compressible turbulent regime. Non-equilibrium models, namely six- and seven-equation, are of interest here because of more accurate wave transmission across interfaces. One approach to capture interfaces with low-dissipative central schemes is to add interface-sharpening terms; moreover, shock and contact-discontinuity capturing may also be achieved with the use of artificial-viscosity approaches. Analogous formulations already developed for four- and five-equation model approaches are extended to these non-equilibrium models by adding the general conservative interface-capturing term based on the phase-field method in the volume fraction transport equation and consistently incorporating the corresponding terms to the phasic conservation equations. The novel formulation is tested for canonical test cases such as two-phase shock-tube and droplet advection problems.