410 Green Chemical Engineering
Breaking spatial symmetry has also been proposed as a means of inducing chaos in
stirred tanks. This could be induced by varying the angle α between the principal axis of
compression or extension and the axis of rotation w. If α = 0, then the ow is symmetric
and consists of nested torii above and below the impeller. However, by tilting the impeller
(α > 0) and consequently geometrically perturbing the system, the ow loses rotational
symmetry, and chaos arises. More recently, Alvarez et al. (2000) demonstrated that for
some values of geometrical eccentricity, widespread chaos is achieved and a signicant
reduction in mixing time is observed with respect to concentric stirred tank systems using
generic impel ...