Ice slurries have a wide range of applications, being involved
from food processing to water purification processes, with
a special relevance on refrigeration and energy storage. The
high cooling capacity and constant cooling temperature,
together with their easy transportability make the ice slurries
a suitable coolant. Among the different techniques available
for the production of ice slurries (Zhang and Ma, 2012), the
scraper type systems and particularly the scraper surface heat
exchangers (SSHE) deserve an special interest. Their ability for
the fouling prevention is applied here for the continuous
removal of the ice layer, generating small ice crystals and
adding them to the mixture. Moreover the continuous
removal of the boundary layer enhances the heat transfer
between the wall and the surrounding fluid.
The aim of the present work is the experimental study of
the ice slurry generation in a SSPHE working in batch mode.
An analysis of the phase-change heat transfer process that
occurs during the ice slurry generation is presented, based on
the appropriate parameters and dimensionless numbers that
help describe the involved phenomena. A through characterization
of the heat transfer to the scraped-surface wall is
accounted for by means of the influence of various
parameters (blade rotation speed, type of scrapers, wall
supercooling degree, product concentration) for a 7 wt. % wt.
NaCl brine. We propose design correlations able to predict the
heat transfer at a scraped surface when freezing of water
occurs.