Comparing turbulent dispersion models for RANS simulations of particle-laden flows

The ingestion of sand-particles into turbomachinery decreases their longevity and performance and can even lead to failure. To address these problems, studying particle deposition and erosion is of high interest in the field. For engineering design, RANS remains an important tool for analyzing turbulent flow behavior, due to low computational cost. RANS simulations solve for the time averaged velocity field. This presents an issue for particle-laden flow analysis since particles are affected by the velocity fluctuations within the flow field. In order to get physical results, RANS simulations are augmented with particle dispersion models that include the influence of small scale velocity fluctuations on particle trajectory.

This work investigates sand particle dispersion due particle dispersion models. The work uses a configuration previously described in [Miranda and Palmore, ASME J. Fluids Eng., vol 145, 2023]. Spherical sand-particles ranginging in size from 1 to 200 microns in diameter are released into a long cylindrical tube and exit to strike a test plate. For all simulations, the commercial CFD software Ansys Fluent is used and the RANS simulations are run with Reynolds-Stress and k-omega SST turbulence models. Variants of both the Discrete Random Walk and Continuous Random Walk dispersion models are used. The accuracy of particle trajectories from RANS simulations are evaluated by comparing to LES results.