Scraped Surface Heat Exchanger Orientation Influence on Particle Residence Time Distributions

ABSTRACT Four levels of particle concentration for an “Interaction” experiment and three levels of carboxymethyl cellulose concentration, flow rate, mutator speed and particle size were used for a “Tracer Only” experiment to determine particle residence times in horizontal and vertical scraped surface heat exchangers (SSHEs). Minimum normalized particle residence time (NPRT) was not significantly affected by SSHE orientation in either type in the experiment. However, maximum NPRT was significantly higher with vertical SSHE except in the “Tracer Only” experiment. Average particles traveled faster than average bulk fluid with less deviation in horizontal SSHE whereas mean particle velocity was less than average bulk fluid velocity and had greater deviation in vertical SSHE.