RESIDENCE TIME DISTRIBUTION OF MULTIPLE PARTICLES IN NON-NEWTONIAN HOLDING TUBE FLOW - STATISTICAL-ANALYSIS

Residence times of multiple particles in aqueous solutions of carboxym ethylcellulose (CMC) in a holding tube arrangement were measured at di fferent conditions of fluid viscosity, suspension flow rate, particle sizes and particle concentrations. Nearly neutrally buoyant polystyren e spheres were used to simulate food particles. Residence time distrib ution functions, E(t), applicable to lethality calculations in aseptic processing were developed along with equations to predict the mean (R T(mean)), minimum (RT(min)) and standard deviation (RT(std)) of the re sidence times as a function of process parameters. Results showed that viscosity, flow rate and particle concentration had significant (alph a=0.05) effects on RT(mean), RT(min) and RT(std) while particle size a ffected only RT(std). The ratio of mean residence time to minimum resi dence time was 1.06 to 1.16.