Author(s)

Rząsa Mariusz & Łukasiewicz Ewelina

Abstract

During coagulation, particles with a flocculent shape and an irregular structure are formed in water. In the model sedimentation water presented in this study, three fractions of particles were distinguished and the method of calculating the sedimentation rate presented. Each fraction sediments in a different way due to different forces acting on particles of different shapes. The particles of fraction I are similar in shape to spherical particles, the particles of fraction II are non-spherical particles, and the particles of fraction III are porous agglomerates, for which the formula for liquid flow through a porous bed has been adopted. For the proposed theoretical sinking model for three types of suspensions composed of particles of each fraction, experimental tests were carried out, which confirmed the model predictions. The results for the sedimentation velocity of the monodisperse suspension of fractions I, II, and III are very similar to predictions: for fraction I, the discrepancy between theoretical and experimental results was 9%; for fraction II, 11%; and for fraction III, 17%. This proves a correctly selected methodology, and the proposed model can be used to calculate the sedimentation velocity of monodisperse suspen- sions of various shapes.

Keywords

flocculation, monodisperse suspension, sedimentation modeling.