Investigation of Erosion and Deposition Due to Flows with Particles

In this work, we employed experimental technique to study the issue of particle erosion and deposition in multiphase flows involving both particles of micro/meso- and nanoscale (sand particles and iron oxide particles). Especially, liquids with immersed nanoparticles gained a lot of interest in the recent years due to their enhanced thermal properties. At the same time, this type of fluids is still not widely used in practical and engineering applications, and one of the reasons is a risk of leading to erosion and deposition on, for instance, pipe walls. In our experiments, an aluminum plate was subjected to a flow with particles by immersing it in a beaker with a rotating fluid for 530 h. After this, the plate was investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM), followed by energy dispersive X-ray (EDX) analysis. According to our observations, the erosion was mainly caused by the largest particles (sand particles), while the nanoparticles did not lead to clear erosion but resulted in significant deposition due to strong adhesion, as well as corrosion, resulting in aluminum oxide formation. This issue was also confirmed through theoretical analysis by comparing the momentum response time and the characteristic time of the flow, as well as computational fluid dynamics (CFD) simulations.