exchanger (SSPHE) and described the three stages in which
the formation of the ice slurry occurs: chilling, nucleation and
crystallization. The authors observed increased heat transfer
coefficients for the stage with crystallization, arguing that
although crystal formation on the cooling surface is considered
disadvantageous to heat transfer, liberation of latent
heat of crystallization on the cooling surface actually
increased the heat transfer.
The same authors reported afterwards a study on the heat
transfer and power consumption in a SSHE while freezing
aqueous solutions (Qin et al., 2003b) and on the ice fouling on a
subcooled metal surface (Qin et al., 2003c). They found that
the reduction of the cooler surface supercooling degree may
delay the ice fouling and prolong the induction time or even
perhaps avoid it. However they did not measure the temperatures
at the subcooled wall.
The effect of the electrolyte concentration and the scraping
speed have been studied by Vaessen et al. (2004), who
compared two types of scraped surface heat exchangers
(cooled column disc and scraper cooled wall). The authors
found that for both designs the transport of heat from process
liquid to cooled wall surfaces (without phase change) at
various rotational speeds of the scrapers can be accurately
described by the penetration theory, expressed as.