On a modified pseudopotential lattice Boltzmann model for multicomponent flows. (April 2021)

• Record Type: Journal Article
• Authors: Zhao, Yong; Pereira, Gerald G.; Kuang, Shibo; Shi, Baochang
• Is Part Of: Applied mathematics letters. Volume 114(2021)
• Publication Date: 2021-04
• Subjects: Lattice Boltzmann method -- Multicomponent flows -- Chapman–Enskog analysis; Applied mathematics -- Periodicals; 519.05
• DOI: 10.1016/j.aml.2020.106926
• Languages: English
• ISSNs: 0893-9659

Abstract

Abstract: This paper presents a pseudopotential lattice Boltzmann model for multicomponent flows involving large viscosity ratios. Firstly, a rigorous Chapman–Enskog analysis is conducted to show that previous models cannot recover the correct governing equation with a single-relaxation-time scheme when the viscosity ratio is not unity. Then, based on this analysis, we established a modified model to obtain the correct governing equation by introducing a system relaxation time into the evolution equation. Finally, we validated the modified model by conducting a two-phase cocurrent (Poiseuille) flow with single-relaxation-time and multiple-relaxation-times schemes. The numerical results show that the present model enormously improves the range of the accessible viscosity ratio. For the single-relaxation-time scheme, the viscosity ratio ranges from 1 ∕ 250 to 250 with a fourth order isotropy. For the multiple-relaxation-times scheme, the viscosity ratio is numerically stable and accurate for viscosity ratios between 1 ∕ 1000 to 1000 with fourth order isotropy. Highlights: A rigorous Chapman–Enskog analysis of multicomponent pseudopotential lattice Boltzmann model is conducted. A modified model is established to solve multicomponent flow. The viscosity ratio can up to 250 for SRT scheme, and at least 1000 for MRT scheme.