Simulation of a Swirling Gas-Particle Flow Using Different k-epsilon Models and Particle-Parcel Relationships

We performed several numerical simulations of a co-axial particle-laden swirling air flow in a vertical circular pipe. The air flow is modeled using the unsteady Favre-averaged Navier-Stokes equations. A Lagrangian model is used for the particle motion. The results of the simulations using three versions of the k-epsilon turbulence model (standard, re-normalization group - RNG, and realizable) are compared with experimental mean velocity profiles. The standard model achieved the best overall performance. The realizable model was unable to satisfactorily predict the radial velocity; it is also the most computationally-expensive model. The simulations using the RNG model predicted extra recirculation zones. We also compared the particle and parcel approaches in solving the particle motion. In the latter, multiple similar particles are grouped in a single parcel, thereby reducing the amount of computation.