A mathematical model of turbulence modulation in particle-laden pipe flows

This investigation is concerned with developing a model of the processes involved in turbulence modulation by relatively large particles in dilute gas–solid turbulent flows. The mathematical model, which focuses on two-way coupling, has been developed based on the work of Lightstone and Hodgson (Turbulence modulation in gas–particle flows: a comparison of selected models, “Can. J. Chem. Eng.” 82, 2004, 209–219) to account for both enhancements and reductions in turbulent kinetic energy as well as the particle crossing trajectory effect. The underlying formulation scheme employs an Eulerian–Lagrangian reference frame, i.e. the carrier phase is considered as a continuum system, while the trajectories of individual particles are calculated using a Lagrangian framework. A random walk model is used to solve the particle motion equation. The proposed model, along with turbulence modulation models from the literature, is used to simulate a particle-laden vertical pipe flow. The simulation results show that the new model provides improved predictions of the experimental data.