Slurry erosion of surface imperfections in pipeline systems

This paper highlights erosion studies on two sizes of circular cavities as well as a regular and an irregular weld bead-configurations commonly encountered on pipeline surfaces. The novelty of combining physical experiments and computational fluid dynamics simulation methods provides new insights into the erosive effect of surface imperfections in pipes. The erosion results for each case are normalised with the maximum erosion occurring on a reference cylinder sample placed in-line during the tests. This ratio is defined as the geometric factor. The results suggest that the maximum erosion occurs on the forward-facing edge of the pipe cavities, while the maximum erosion rate occurs on the wind-ward side of the weld. The geometric factor for direct particle impact on the forward-facing edges of surface cavities in water–sand mixtures is found to be nominally half that of air–sand erosion experiments. However, when coupled with more complex systems in low Stokes number flows (e.g. presence of extraneous peaks in irregular weld ridges) the geometry factor can be twice that of direct impact air-based configurations due to the generation of trailing vortices shed from these geometric features. Computational fluid dynamics simulation of the flow field further illustrates the flow complexities that accompany these simple geometric features.