Present work deals with the development of a computational fluid dynamics (CFD) model for understanding the hydrodynamics in sieve and pulsed-sieve plate extraction columns. The model is based on Eulerian-Eulerian approach along with standard k-epsilon model for turbulence. The CFD model has been validated by comparing (i) the height of the accumulated layer of the dispersed phase under the plate, and (ii) hold-up of the dispersed phase on the sieve plates with the corresponding values calculated by the correlations reported by Laddha and Degaleesan [Laddha, G.S., Degaleesan, T.E., 1976. Transport Phenomena in Liquid Extraction. Tata McGraw Hills Publishing Co. Ltd., pp. 305-330]. Model predictions were found to be within +/- 10%. The validated model has been extended to study the regime transition in pulsed-sieve plate columns. Overall, the developed CFD model is found to be able to predict the hydrodynamic aspects of plate extraction columns: like variation in hold-up above and below the plate, movement of continuous phase across the plate and through the downcomer, different operating regimes at different pulsing velocities, etc. (C) 2008 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.