Prediction of critical deposition velocities in particleladen horizontal turbulent pipe flows

Particle-laden turbulent pipe flows are studied using direct numerical simulation of the continuous phase in combination with Lagrangian particle tracking (LPT) to determine critical deposition velocities at four particle Stokes numbers. The work was carried out using the computational fluid dynamic solver, Nek5000, enhanced with a four-way coupled LPT to enable high-fidelity modelling of particle-laden pipe flows. The results indicate that at high Stokes numbers, the particle dispersion function and mean vertical displacement values fall quickly, with the formation of particle beds. However, at lower Stokes number thinner dune-like structures are formed. It is determined that using a volume-coverage percentage in the near-wall region of the lower half of the pipe to identify the onset of deposition provides good agreement with experimental data and an empirical correlation for the critical deposition velocity. Insight into the migratory behaviour of the solid phase is determined through additional analysis of the particle dynamics.