Stable mesh-free moving particle semi-implicit method for direct analysis of gas–liquid two-phase flow

Abstract

In a metallurgical process, gas–liquid flow plays an important role in increasing the efficiency by stirring liquid mechanically or by injecting a gas. Owing to the difficulty of direct observation in a high-temperature system or real furnace experiment, numerical analysis is useful and widely studied. However, flexible treatment of complicated free surface behavior such as fragmentation and coalescence of liquids is still a difficult problem. This paper presents a new particle-based simulation scheme for gas–liquid flow. We improved the numerical stability, which is generally a problem with the particle method, and verified the model’s accuracy for fundamental gas–liquid flow analysis.Because all the phases were discretized as particles in Moving Particle Semi-implicit (MPS) method, the proposed model can track the movement of both the gas and liquid phases directly. A large difference in the real density between the gas and liquid phases makes the gas–liquid interface behavior unstable. This study proposed an optimization of the weakly compressible Poisson equation, an initial particle arrangement, and a smoothed interface density in order to stabilize the multi-density flow analysis. This model guarantees conservation of the fluid volume even for a high-density-ratio flow like that at a gas–liquid interface. Therefore, a gas–liquid interface has been represented with high accuracy. We believe that this scheme is also applicable to phenomena in an actual process that includes many dispersal phases.