abstract
In most published studies regarding the numerical simulation of cyclone separators, the gas outlet duct is
usually treated as a short straight duct, differing considerably from the experimental apparatus, in which
a relatively long duct followed by a curve, or vice versa, is generally used. This work focuses on the influence
of length and shape of the outlet duct on the grade efficiency and pressure drop inside a small
cyclone separator. The results are obtained through Large Eddy Simulation of the fluid flow inside the
separator, coupled with a concomitant Lagrangian description-based on Newton’s second law-of the dispersed
phase. More than thirty different outlet duct configurations, including different lengths, curves,
curves positions and curvature radii were simulated. The results show that the cyclone gas outlet duct
may affect the cyclone performance: the pressure drop initially decreases with duct length until a minimum
is reached, and from this point on it monotonically increases with duct length. As for the cut off
diameter, the relation showed itself much more complex.