Micro-scale Flow Conditions Leading to the Onset of Erosion

The flow conditions influencing the onset of contact erosion have been investigated physically using a novel setup based on the Particle Imaging Velocimetry (PIV) and numerically using a coupled DEM-LBM (Discrete Element Method-Lattice Boltzmann Method) approach. The flow conditions at the transition from base to filter material were experimentally quantified and computationally simulated resulting in a satisfactorily good agreement. An interesting and important outcome of these investigations is that the maximum flow velocity is not appearing in the base material, but in the constriction of the filter material in the transition zone from base to filter just above the surface of the base material. A generalised relationship between flow velocity and geometrical conditions at the transition zone was developed based on the Froude number. The characteristic evolution of the curve clearly shows the competition between hydraulic and geometric/mechanical conditions influencing the onset of contact erosion.