Fundamental comparison between the pseudopotential and the free energy lattice Boltzmann methods

Author(s)

Czelusniak, Luiz Eduardo ; Martins, Ivan Talao ; Gomez, Luben Cabezas ; Bulgarelli, Natan Augusto Vieira ; Verde, William Monte ; de Castro, Marcelo Souza

• Document type: Journal article
• Source: PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS; v. 660, p. 17-pg., 2025-01-22.

Abstract

The pseudopotential and free energy models are two popular extensions of the lattice Boltzmann method for multiphase flows. Until now, they have been developed apart from each other in the literature. However, important questions about whether each method performs better needs to be solved. In this work, we perform a fundamental comparison between both methods through basic numerical tests. This comparison is only possible because we developed a novel approach for controlling the interface thickness in the pseudopotential method independently on the equation of state. In this way, it is possible to compare both methods maintaining the same equilibrium densities, interface thickness, surface tension and equation of state parameters. The well-balanced approach was selected to represent the free energy. We found that the free energy one is more practical to use, as it is not necessary to carry out previous simulations to determine simulation parameters (interface thickness, surface tension, etc.). In addition, the tests proofed that the free energy model is more accurate than the pseudopotential model. Furthermore, the pseudopotential method suffers from a lack of thermodynamic consistency even when applying the corrections proposed in the literature. On the other hand, for both static and dynamic tests we verified that the pseudopotential method was able to simulate lower reduced temperature than the free energy one. We hope that these results will guide authors in the use of each method. (AU)

• FAPESP's process: 23/02383-6 - Development of a phase-field lattice Boltzmann method to simulate thermal liquid-gas phase change phenomena for engineering applications
• Grantee: Ivan Talão Martins
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 17/15736-3 - Engineering Research Centre in Reservoir and Production Management
• Grantee: Denis José Schiozer
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 22/08305-4 - Experimental study and numerical modelling of the phase inversion phenomenon within centrifugal pumps
• Grantee: Luiz Eduardo Czelusniak
• Support Opportunities: Scholarships in Brazil - Post-Doctoral