Abstract
An experimental study of mixing in autoclave vessel equipped with an anchor impeller was performed on the sludge proceeding
from the treatment of mixed municipal and industrial wastewater. This unit operation is part of a process for the recovery of
sludge. The mathematical modelling of the mixing was done having in view the scaling-up of this process. The mathematical
model allows the calculation of the mixing power N as a function of the impeller diameter d, the vessel diameter D, the fluid level
in the vessel H and the Reynolds number Re, in a dimensionless equation. Finding the model
parameters was the challenge of this work and for this, 384 sets of experimental data were processed. Since r was a constant, the
parameters k, p and q allow the determination of the function of the dry matter fraction f. The good agreement between
experimental and computed data in the laminar regime up to Re = 10 proves that the model is fit for the dimensioning of
industrial mixers.