DIMENSIONLESS ANALYSIS OF THE FLOW OF SPHERICAL-PARTICLES IN 2-PHASE FLOW IN STRAIGHT TUBES

In the aseptic processing of particulate fluid foods, the residence ti me distribution of particles and the fluid-to-particle heat transfer a re intimately related to the linear and rotational velocities of the p articles. The development of models correlating these velocities with fluid and particle characteristics and with operating conditions is th erefore very useful, as it provides a fast method to estimate fluid-to -particle heat transfer coefficients without measuring the actual part icle velocities. The models can further be used to estimate the averag e residence time of the particles. Data for modelling particle linear and rotational velocities were obtained by videotaping the flow, along the wall, of individual spherical particles in transparent 2-m long s traight tubes. Linear and rotational velocities were correlated with g eneralized Reynolds, Archimedes and Froude diameter ratio. The models obtained had correlation coefficients of 0.89 and 0.86 for the particl e linear and rotational velocities, respectively. @ 1997 Elsevier Scie nce Limited.