Quantifying mixing in 3D binary particulate systems

To evaluate the quality of mixedness in particulate systems, either through experiments or with CFD simulations, proper quantification methods are necessary. Two analysis tools are presented here that allow for quantitative assessment of the mixedness of binary particulate systems when its internal structure is known, either through experimental tomographic techniques or through numerical simulations; they are a newly-defined Particle Segregation Number (PSN) and the Cube Analysis (CA). The study has been conducted using simulated material distributions in a 3D cylindrical vessel which approximates a collapsed fluidized bed. The particle distribution is denoted in terms of volume concentration per voxel (i.e., a 3D pixel). The results show that the PSN and CA measures are independent of particle size, material densities, and overall volume fraction, which is not true for other available segregation measures, and can therefore be used over a wide range of operating conditions to assess and compare particulate mixing. Furthermore, it was found that using these methods allows for capturing even small changes in the overall bed segregation condition.

Sample series of images showing center slice through 3D images with 25% by volume flotsam, and radial location of r/R=0.75.Figure optionsDownload high-quality image (155 K)Download as PowerPoint slideHighlights
► Quantifying mixing/segregation in 3D multi-component particulate systems.
► Two analysis tools are introduced that are superior to existing methods.
► Analysis tools allow quantification of mixedness in 3D particulate systems.
► Sensitivity and completeness of information exceeds earlier introduced methods.
► The findings can help bridge the gap between experimental and computational efforts.