Turbulence Models for Compressible Disperse Multiphase Flows

Multiphase turbulence driven by coupling between the phases can arise in the absence of mean shear. For example, due to gravity (or other body forces) in disperse multiphase flows (e.g., particle-laden and bubbly flows), the mean-slip velocity between phases and spontaneous cluster formation generate strong turbulence that is nearly one dimensional. Such complex flows can be modeled using Eulerian–Eulerian two-fluid models. Here, starting from a compressible two-fluid model, a Reynolds-averaged turbulence model is derived for disperse multiphase flows driven by gravity. Due to the diagonal form of the Reynolds-stress tensors, the model equations are hyperbolic and thus require time-dependent solutions and dedicated numerical solvers.