Effects of Turbulence Modeling and Parcel Approach on Dispersed Two-Phase Swirling Flow

TL;DR

This study compares different turbulence models and particle approaches in simulating dispersed swirling flows, highlighting the standard k-epsilon model's accuracy and the computational benefits of the parcel method.

Contribution

It evaluates the performance of three turbulence models and two particle approaches in simulating two-phase swirling flows, providing insights into their accuracy and computational efficiency.

Findings

Standard k-epsilon model performed best overall.

Realizable model was less accurate and more computationally expensive.

RNG model predicted additional recirculation zones.

Abstract

Several numerical simulations of a co-axial particle-laden swirling air flow in a vertical circular pipe were performed. The air flow was modeled using the unsteady Favre-averaged Navier-Stokes equations. A Lagrangian model was used for the particle motion. The gas and particles are coupled through two-way momentum exchange. 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 additional 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.