Kinetic Simulations of Compressible Non-Ideal Fluids: From Supercritical Flows to Phase-Change and Exotic Behavior

We investigate a kinetic model for compressible non-ideal fluids. The model imposes the local thermodynamic pressure through a rescaling of the particle's velocities, which accounts for both long- and short-range effects and hence full thermodynamic consistency. The model is fully Galilean invariant and treats mass, momentum, and energy as local conservation laws. The analysis and derivation of the hydrodynamic limit is followed by the assessment of accuracy and robustness through benchmark simulations ranging from the Joule-Thompson effect to a phase-change and high-speed flows. In particular, we show the direct simulation of the inversion line of a van der Waals gas followed by simulations of phase-change such as the one-dimensional evaporation of a saturated liquid, nucleate, and film boiling and eventually, we investigate the stability of a perturbed strong shock front in two different fluid mediums. In all of the cases, we find excellent agreement with the corresponding theoretical analysis and experimental correlations. We show that our model can operate in the entire phase diagram, including super- as well as sub-critical regimes and inherently captures phase-change phenomena.

Automated summary

The study presents a kinetic model for compressible non-ideal fluids that imposes local thermodynamic pressure through rescaling particle velocities for full thermodynamic consistency. The model, which is Galilean invariant, treats mass, momentum, and energy as local conservation laws. Benchmark simulations demonstrate accurate and robust performance across different scenarios, showing excellent agreement with theoretical analysis and experimental correlations. The model is capable of operating in the entire phase diagram, including super- and sub-critical regimes, and inherently captures phase-change phenomena.