FARIAS, F. P. M.; http://lattes.cnpq.br/2083728291220996; FARIAS, Fabiana Pimentel Macêdo.
Résumé:
Cyclones are equipments very used in chemical processes, in several units operations.
Their aim is to promote the solid and/or a liquid separation from a gas stream and dry
solids. In this sense, the present work proposes a theoretical study of thermal fluid
dynamics of a cyclone as dryer. The mathematical model considers three-dimensional,
turbulent and stationary flow for gas phase, and Lagrange model for particles. The
governing equations were solved numerically with the finite-volumes method, using
UPWIND interpolation scheme for convective terms and algorithm SIMPLEC for
pressure-velocity coupling. As an application, the methodology was used to predict the
sugar cane bagasse drying in a cyclone. Simulations had been carried out using the
computational code CFX-3D. Results of the moisture content, temperature and
dimensional variations of the particles and velocity, pressure and temperature distributions
of the air drying, to several air conditions, shape of the cyclone and initial velocity of
particle is presented and analyzed. Three-dimensional gas-particle flow, recirculation
zones and inversion flow were verified inside the cyclone. Numerical data fitted well
experimental ones. It was verified that the kinetic drying, temperature and residence time
of the particles were affected by air drying conditions and cyclone geometry. Cyclone with
square inlet section were more efficient to dry than cyclone with vertical and horizontal
rectangular section duct.
