Abstract:
A generalized conservative phase-field simplified lattice Boltzmann method is proposed, which is suitable for incompressible and immiscible complex multiphase flow problems. This method extends our earlier simplified multiphase lattice Boltzmann method (SMLBM) by using a generalized conservative equation with Lagrange multiplier to control the evolution of the interface and ensures the conservations of the volume and total mass of each phase. Moreover, the SMLBM mimics the fluid systems and interface dynamics with a predictor-corrector scheme in the frame of single-relaxation lattice Boltzmann method by considering only the evolution of equilibrium distribution function, which can be directly calculated from the macroscopic variables. Therefore, this method inherits the advantages of good stability, high computational efficiency, and easy implementation of boundary conditions of the SMLBM, which is utilized for solving the interface problems with large gradients induced by large density ratios and large viscosity ratios between different fluid components. To validate the present method, four multiphase flow examples including Laplace law, spreading of a liquid lens, Poiseuille flow with three phases and spreading of a compound droplet are simulated. The results show that this method can effectively simulate complex interface multiphase flows with the density ratio of 1200 and the viscosity ratio of 500.