Analysis of the void distribution in a circular tube with the two-fluid particle interaction method

A particle interaction method called MPS (Moving particle Semi-Implicit) has been developed in recent years, which formulates the differential operators in Navier-Stokes' equation as interactions between particles characterized by a kernel function and adopts a mesh-free algorithm. This method is suitable especially for treating fluid breakup. We have extended this method to a two-fluid (liquid-liquid and gas-liquid) system and introduced a potential-type surface tension to calculate the two-phase flow without experimental correlation. With this extended method, a several number of two-phase flow experiments were analyzed successfully as reported in out previous paper. Herein, as one of the verification studies, the experiment by Valukina et al. was analyzed to show that our method could reproduce the bubble size effect on the radial void distribution in a circular tube. The experiment showed that the radial void distribution change drastically as the bubble size changes. Our previous work with SIMMER-IV code which has a general solver for multi-phase flows revealed that the 'lateral lift force' and 'wall force' should be introduced into the momentum conservation equation to reproduce the bubble size effect. We evaluated these forces using the velocities of particles calculated by our particle method and compared with the SIMMER-IV results. (author)