Scale attachment and detachment: The role of hydrodynamics and surface morphology

Crystallization fouling presents a significant challenge in a wide range of industries. Accurate understanding of crystal formation is crucial for planning preventative measures and maximizing the effectiveness of maintenance interventions. In this study, we demonstrate that understanding net deposition rates depends on the knowledge of the detachment mechanisms and deposition distribution characteristics. We quantify deposition in a once-through flow set-up and visualize crystal formation through high-resolution X-ray micro-computed tomography scanning. Additionally, we quantify the height distribution of deposited crystals through computed surface texture parameters. Finally, we used computational fluid dynamics, implementing large-eddy simulations turbulence modeling and Eulerian transport of chemical species, to describe bulk and wall reactions and quantify energy and mass transport in turbulent eddies. Results show that attachment and detachment processes depend on fluid hydrodynamics; the influx of material determines the overall deposition to the surface, while the deposition pattern is governed by the surface morphology of the initial surface morphology. Our findings provide a foundation for understanding fouling mechanisms and present a template for developing more accurate prediction models.