The particle fluid model and using Lagrangian representation in two-phase flow modeling

Abstract Particle Fluid Model (PFM) is an intermediate method between the numerically intractable local instant model and the fully averaged two-fluid model for simulating transient two-phase flows. PFM uses a Lagrangian description for the dispersed phase and an Eulerian description for the continuous phase. In this paper we report a new way to model bubble lateral transport and the resulting void–fraction profile in bubbly flows simulated by the PFM. This model is based on eddy–bubble interactions. Eddies are generated by two mechanisms namely the wall-shear induced turbulence and the bubble–wake induced turbulence. Fluctuating components of velocity due to both of these effects are obtained separately. A linear superposition of turbulent kinetic energies is performed to obtain the resultant velocity fluctuations. An empirical model is used to determine the eddy size distribution in the pipe. The bubble momentum equation is solved through a succession of eddies to establish the lateral position of that bubble. This paper presents details of our bubble dispersion model and its assessment using experimental data of Serizawa.