VERTICAL FLOWS OF SOLID-LIQUID FOOD MIXTURES

A number of commercial food processes involve vertical pipework, in wh ich food mixtures are either conveyed or processed. It is important to know the flow patterns of particles within such systems. Experimental work has been carried out to study the vertical flows of solid-liquid mixtures of up to 25% solids fraction in up- and down-flow for partic les of 6-10 mm diameter and for different carrier fluids: water 0.3%, 0.8% CMC and 4% starch. Particle times-of-flight were measured using m etal detectors. distributions could show (i) a single peak, resulting from particle migration to particular radii, and (ii) two peaks, corre sponding to wall and central regions of the flow. Data have been expre ssed as mean slip velocities; the greatest variation is found with sta rch. (C) 1998 Elsevier Science Limited. All rights reserved.