Discrete Boltzmann Modeling of Multiphase Flow Systems With Gravity

A discrete Boltzmann model (DBM) for multiphase flow systems with gravity is proposed. Based on the theory of kinetics, the discrete Boltzmann equations in a uniform form are employed to describe the evolution of multiphase flows. On the right-side of the equations, the phase transition source term is added to describe the phase transition phenomenon, and the external force term is introduced to describe the influence of gravity field. Based on the Hermite polynomial theory, a two-dimensional 33-velocities model is introduced. Via the chapman-enskog analysis, it is demonstrated that the DBM can not only recover the Navier-Stokes equations involving the intermolecular interaction and external force, but also describe some thermodynamic non-equilibrium behaviors. Finally, this DBM is verified by four numerical benchmarks, including the free-falling process, gas-liquid coexistence curve, Sod shock tube, and bubble coalesence. © 2024 Science Press. All rights reserved.