A numerical investigation of wear caused by dilute slurry injected into an annulus through rectangular apertures

Slurries conveyed in conduits generate erosion caused by particle impacts on the walls. Those impacts result from the average velocity and the turbulence of the carrying liquid. We investigate the erosion and relevant flow features, when the dilute slurry passes from the inner to the outer annulus through four equally spaced rectangular apertures on the periphery of the tube dividing these two conduits. The flow of dilute slurry was solved numerically. A consideration was given to the effects of particle size on erosion rate and statistical distribution of impact velocity, angle, and total erodent mass inducing wear. In addition, the numerical solution of the continuous phase velocity was validated with measurements. A confined trailing vortex forms at the longitudinal edge of the aperture, amplifying the erosive wear on the outer wall of the annulus. A large amount of particles passes near the aperture׳s horizontal downstream edge and intensifies the erosion rate above it. The effect of these flow features becomes more pronounced for larger particles. The statistical analysis of impact velocity, angle, and mass showed that the mean velocity in the channel dominates erosion caused by impacts of large particles. On the other hand, the near-wall turbulence mainly affects the erosion resulting from impacts by small particles.