Diffuse-interface modeling of liquid-vapor coexistence in equilibrium drops using smoothed particle hydrodynamics

Area of Science:

• Thermodynamics
• Fluid Dynamics
• Computational Physics

Background:

• Understanding liquid-vapor phase separation is crucial in various physical and chemical processes.
• Previous smoothed particle hydrodynamics (SPH) simulations often lacked full adaptivity.
• The van der Waals (vdW) model provides a theoretical framework for fluid behavior near phase transitions.

Purpose of the Study:

• To numerically investigate liquid-vapor phase separation in two-dimensional, nonisothermal vdW liquid drops.
• To develop and apply a fully adaptive SPH method incorporating a diffuse-interface model and Korteweg forces.
• To validate simulation results against theoretical predictions and experimental data.

Main Methods:

• Utilized the method of smoothed particle hydrodynamics (SPH) for numerical simulation.
• Employed a fully adaptive, diffuse-interface model for a single-component fluid.
• Incorporated reversible, capillary (Korteweg) forces to model phase interfaces and surface tension.

Main Results:

• Predicted the formation of stable, subcritical liquid drops with a vapor atmosphere.
• Observed densities and temperatures of coexisting phases closely matching the vdW binodal curve.
• Surface tension values agreed well with the Young-Laplace equation, independent simulations, and experimental data.

Conclusions:

• The numerical model accurately captures liquid-vapor phase separation phenomena in vdW fluids.
• The simulations successfully reproduce the Clausius-Clapeyron relation, enabling vaporization pressure calculations.
• The adaptive SPH approach offers a robust method for studying interfacial phenomena in fluid dynamics.