RESIDENCE TIME DISTRIBUTION OF PARTICLES DURING 2-PHASE NON-NEWTONIANFLOW IN CONVENTIONAL AS COMPARED WITH HELICAL HOLDING TUBES

The residence times of multiple particles during the flow of a non-New tonian suspension through a conventional holding tube assembly were co mpared with that in a helical holding tube assembly of identical lengt h and tube diameter. The residence times were measured for different c ombinations of process parameters (viscosity, flow rate of fluid, size and concentration of particles). The effects of these parameters on R esidence Time Distribution (RTD) of particles was determined and dimen sionless equations were developed to predict the mean, minimum and sta ndard deviation of residence times. The RTDs in the helical holding tu be were found to be narrower than in the conventional holding tube. Th e RTD of particles at all combinations of process parameters were norm ally distributed. The ratio of mean to minimum residence time was with in 1.05 to 1.11 in the helical holding tube and 1.06 to 1.16 in the co nventional holding tube for the range of parameters studied.