Turbulence modulation of gas-particle flow in a vertical channel using eulerian-lagrangian approach

Abstract

Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.

Turbulent gas-solid flow in a vertical channel is investigated numerically using Eulerian-Lagrangian approach. Low Reynolds Number k-l model is used fur studying the fluid phase. A new model is presented based on a source-term formulation, which can predict turbulent augmentation due on large particles and reduction of turbulence due on small particles in the core of the channel. The particle trajectories and velocities are determined by integrating the particle equations of motion. Particle-particle and particle-wall collisions are simulated based on deterministic approach and coupling terms representing the fluid-particle interactions are also taken into account In this study, dilute or moderate suspensions are considered. The predicted fluid mean velocity and turbulent intensity profiles are in fine agreement with the available experimental data. Additional numerical results such as the eddy viscosity, the turbulent production and dissipation are also investigated fur different values of loading ratio by means of a complete four-way coupling description. The results, comparing on integral length scale, show large particles augmenting turbulence in the core of the channel and small particle reducing turbulence. These effects are increased by inter-particle collision and increasing loading ratio.