Effect of groove depth on the slurry erosion of V-shaped grooved surfaces

Abstract

The fabrication of microstructures on surfaces is an innovative approach to relieve slurry erosion. Understanding the effect of the dimensions of the surface microstructure on slurry erosion can inspire new surface treatments, not only for small flow-handling parts but also for large water conservancy facilities. Our previous work has studied the effect of the micro structure's shape on slurry erosion. As an extension, the dimension was investigated based on the selected groove structure. Five V-shaped grooved surface microstructures (V1–V5) with different depths (1–5 mm, respectively) were designed. The effect of groove depth on erosion was studied by scanning electron microscopy observation and mass loss, roughness, and residual stress measurements at a slurry speed of 8.29 m s-1, particle size of 75–150 mesh, and sand concentration of 3 wt%. The results showed that the best erosion resistance occurred at a critical depth of 3 mm. This was partially due to the low-velocity component in the flow direction and the upward velocity component perpendicular to the flow direction. This velocity distribution inhibited the impingement erosion of the particles inside the groove and simultaneously slowed the incoming particles into the groove. The groove surfaces underwent the most severe erosion, while the top surfaces experienced less erosion, which was relieved by multiple vortices induced by the grooves. The erosion rates of V3, V4, and V5 were lower than those of V1 and V2. The erosion mechanisms are summarized to guide the design optimization of surface microstructures.