APPLICAZIONE DELLA TEORIA DI KYNCH NELLA SEDIMENTAZIONE GRAVITAZIONALE DI SOSPENSIONI ALIMENTARI COLLOIDALI

A new method, based on Kynch theory of gravitational sedimentation, to calculate partly the flux density of solids’ volume fraction q(c) and then the propagation velocity ua of the sediment shock, was proposed to reduce the number of preliminary tests. A few sedimentation tests on wine lees, characterized by a colloidal and flocculant behaviour and diluite in water at several volumetric concentration Co was carried-out. The experimentation was repeated with two different initial volumes (α and β). So the relative time-height (t-z) charts were drawn with in evidence the upper front wave (shock). Through the measurement of the shock propagation velocity, the flux density function q(c) was partly mathematically represented by the new method and then the propagation velocity of the sediment shock ua was calculated. The comparison between these calculated shock velocities and the experimental ones, taken from z-t charts, showed a very good corrispondence when the volumetric concentration c0 was upper 0.2, whereas an average error of 20% existed at Co equal or under 0.2. Besides the difference between the experimental results, obtained from two different initial volumes (α and β), was negligible.