Influence of solid particles in liquid tank on sloshing behaviour based on CFD-DEM coupling method

Abstract

This paper employs multiphase flow theory to investigate the influence of different solid particle densities on the sloshing characteristics within a liquid tank. A numerical model of gas-liquid-solid multiphase flow sloshing motion within the tank was established using the Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) coupling method, simulating the interactive coupling between the two-phase fluid and solid particles. In this context, the gas-liquid two-phase fluid is treated as a continuous phase, described under the Eulerian framework, with the Volume of Fluid (VOF) method applied to capture the gas-liquid interface. Conversely, the solid particles are treated as a discrete phase, described under the Lagrangian framework. The effects of different solid particle densities on the tank sloshing characteristics were analyzed utilizing the STAR-CCM + software platform. Initially, the validity of the CFD-DEM method was confirmed by simulating classical scenarios such as a single spherical particle falling from air into water and the flow dynamics of a gas-liquid-solid three-phase dam break. Subsequently, a numerical simulation of sloshing in a pure water tank was conducted and compared with published experimental results, thereby verifying the feasibility of the numerical method for gas-liquid two-phase sloshing. Following this, a series of simulations were conducted on a pure water tank to validate the effectiveness of the numerical method for gas-liquid two-phase fluid sloshing. Subsequently, solid particles were introduced to the model, and the effect of solid particle densities on sloshing load and response under forced motion was studied. Finally, by comparing and analyzing the sloshing-induced pressure on the tank walls and the amplitude of the free surface motion across different solid particle densities and as well as different excitation frequencies, the sloshing characteristics of the solid-liquid mixed two-phase flow were investigated. The computational results indicate that an increase in solid particle density corresponds to an increase in liquid surface wave amplitude. This suggests that lighter solid particles have a greater damping effect on tank sloshing. It can be inferred that when the density of solid particles is maintained at a constant level, the closer the external excitation frequency is to the natural frequency, the more effective the sloshing suppression effect. This is attributed to the fact that, as sloshing intensifies, fluid velocity increases, resulting in greater damping due to viscosity effects, thereby enhancing the sloshing suppression.