BEND-EFFECTS ON THE RESIDENCE TIME DISTRIBUTION OF SOLID FOOD PARTICLES IN A HOLDING TUBE

The residence time distribution (RTD) of individual food particles in the curved section (180 degrees) of a holding tube of an aseptic proce ssing simulator was investigated. Process variables were the radius of curvature (R=0.1 and 0.2 m) of the bend, type, size and shape of the food particles and type of carrier liquid (water or pectin solutions). The results obtained by a videotaping technique indicated that the li near velocity of food particles in the curved section (bend) was reduc ed from about 8% (R=0.2 m) to about 15% (R=0.1 m) in comparison to the velocity in the straight section. Particle size and shape, and viscos ity of the carrier liquid influenced the velocity of the food particle in the curved section, but only the shape effect was similar to that in straight part of the tube.