  This work studies the design of a device conveying dust and sand in order to
understand how the particles impinge, erode and rebound from a target plate.
The motivation behind this study is understanding dust ingestion and erosion in
aviation gas-turbine engines. The conveying system consists of a constant area
duct in which particles are injected in the upstream direction using a particle
seeder. The particles exit the duct through a converging nozzle and are
directed towards a target plate. Particles of varying sizes are tested at two
different gas speeds.
  The particle velocity at the conveyor duct exit follows a trend inversely
proportional to diameter. After exiting, particles respond differently to
changes in the flow field based on their diameter. The largest particles move
ballistically, so they impact the target with nearly the same velocity they had
at the duct exit. However, small particles follow the flow streamlines around
the target. This causes them to both significantly slow down and to disperse in
all directions. The combination of the exit velocity and the near-target
trajectory behaviors leads to a non-monotonic trend of particle impact velocity
as a function of particle diameter. The importance of these effects depends
strongly on the relative angle between the conveyor duct and the target plate.
  LES are compared to RANS, and it is demonstrated that RANS are capable of
accurately predicting mean particle impact statistics. However, RANS results
display narrower statistical variation than LES, which suggests that particle
dispersion is underpredicted in RANS.
