Highly concentrated slurries are found in many different industrial and environmental applications, such as hydro-transport systems of the oil sands industry, drilling and fracturing applications, and stirring vessels. When the volume fraction of particles is low, particles have little influence on the structure of the flow. However, even when average concentration is relatively low, there can still be some regions of high concentration. In highly concentrated flows, the effect of particles on the dynamics of the flow cannot be neglected. Under this condition, particle concentration can affect the turbulence intensity and erosion ratio.
Several experiments have been conducted to examine the effect of different parameters on erosion. Different models have been developed to predict erosion ratio in liquid and gas flows. However, previous studies mostly have examined dilute slurries and less attention has been paid to the effect of high concentration of particles on erosion. In this study, the erosion due to highly concentrated slurries is investigated using both experimental and numerical approaches. There are several parameters such as particle properties and shape, target material, fluid properties and dynamics of the flow that affect erosion ratio. In addition, higher fluid viscosity can significantly affect the flow dynamics and change the interaction behavior between fluid and solid particles.
Effects of particle size and velocity on erosion ratio are investigated for different sand concentrations. Experiments have been conducted for various concentrations, ranging from 1% to about 20% by mass and two different particle sizes, 75 μm and 300 μm. Erosion ratio was calculated based on two different approaches, mass loss and volume loss obtained from 3-D profilometry data. Scanning electron microscope (SEM) images were obtained for 1% and 15% concentration cases to examine the erosion on different parts of the specimens. In addition to the experimental work, a CFD model is setup to simulate the erosion results. The aim of this CFD simulation is to predict erosion rate of the specimen caused by submerged slurry jet flow by using Reynolds stress as turbulence model. The fluid flow solution is obtained using an Eulerian approach and a Lagrangian scheme is used to track the sand particles. In these models, the injected particles from the inlet impact the target wall in order to investigate the erosion.