Solid area fraction distribution of solid–liquid food mixtures during flow through a straight tube

Abstract

The solid area fraction (areal porosity) distribution within a tube during continuous flow was determined experimentally. Cubes, rectangular prisms and cylinders (potato and green beans) at volume fractions of 30% and 50% in a 5% agar solution were tested. The flowing mixture was rapidly immobilized by cooling-induced gelation. Samples were then sliced to determine solids area fractions. Results of the solid fraction distribution showed a normal distribution. Increasing solid concentration flattened the distribution. The solid concentration was the only significant factor that affected both the area and flowing solid volume fraction. Solid volume fraction always was lower than solid area fraction. The aspect ratio and the shape effect were not statistically significant but they had slight effects on the mean and standard deviation. Rectangular solids exhibited lower solid area fraction and flattened the distribution more than cylinders at high solid concentration.