W. Hanselmann et E. Windhab, Flow characteristics and modelling of foam generation in a continuous rotor/stator mixer, J FOOD ENG, 38(4), 1998, pp. 393-405
Within this study, the Newton/Reynolds characteristics of a continuous roto
r/stator mixer for foam production were determined with special geometrical
ly adapted Newton and Reynolds numbers. A critical Reynolds number of 105 w
as derived. Equations for the laminar and turbulent flow field for pre-calc
ulating the maximum bubble size in rotor/stater mixers were derived and exp
erimentally confirmed. These equations combine process, recipe and geometry
parameters and a direct scale-up is possible. An increase of the rotor spe
ed from 600 to 2000 rpm resulted in a decrease in bubble size of about a fa
ctor of 4.5 for a low viscous liquid, whereas for a highly viscous liquid,
the decrease in bubble size in the same rotor speed range was only 20%. Dra
inage stability improvement of about 100% and an increase in foam viscosity
of about 100% were achieved in the same rpm range. (C) 1999 Elsevier Scien
ce Limited. All rights reserved.