Onset of abrasive wear of boundaries in concentrated suspension flow

• A mathematical procedure was developed to calculate the onset of abrasive wear of boundaries in concentrated suspensions.
• An apparatus was designed and built to evaluate wear onset conditions in suspension flow.
• Particle concentration, flow rate, and surface yield strength effects were examined.
• There is a good agreement between the results from the experiments and the calculations, with potential application in polishing or erosion.

A predictive model for abrasion of boundaries by a flowing suspension is developed. The basis of the model is that wear arises when the local normal stresses exerted by particles in the shear flow exceed the material strength of the boundary. From this threshold stress, one deduces an onset shear rate at which abrasion will be observed for a given particle loading and liquid viscosity. An apparatus was designed to examine the effect of particle concentrations of 30–50% by volume particles at varying flow rates using materials of varying surface yield strengths. This provided a wide range of conditions to study the model predictions, using soft substrates. Agreement of model and experiment is good.