Research on the Acoustic Emission Mechanism of Superfluous Metallic Contaminants in Slurry Preparation Process Based on DEM

In order to elucidate the mechanism by which superfluous metallic contaminants enter and evolve within the slurry preparation process, discrete element method (DEM) simulations are performed to characterize the coupled flow, particle motion, and acoustic fields in a slurry preparation device. The device-scale velocity and pressure distributions are first obtained, and a particle-tracking strategy is then adopted to quantify the trajectories and kinematic features of metallic contaminants entrained into the flow. A monopole point-source acoustic model is subsequently constructed for the purpose of examining the propagation pathways of acoustic emission signals and the spatial distribution of sound pressure within the device. The experimental tests were conducted to validate the numerical predictions. The results demonstrate that high-velocity regions are predominantly concentrated around the impeller blades and within the narrow gaps between the blades and the casing. Furthermore, high-viscosity slurries exhibit more pronounced velocity localization near the blade surfaces. Upon entering the flow field, metallic contaminants rapidly decelerate and repeatedly collide with the device, generating continuous acoustic emission signals along with serrated trajectories. The findings, when considered collectively, provide mechanistic evidence that supports the use of acoustic emission signal-based detection of metallic contaminants during slurry preparation.