Studies in the expansion behaviour of tapered fluidized bed systems are important for specifying the height of the bed Data have been obtained on the expanded heights of tapered fluidized beds and bed expansion ratios for spherical and non-spherical particles have been calculated Based on dimensional analysis, models have been developed as a function of geometry of tapered bed, static bed height.. particle diameter, density of solid and gas and superficial velocity of the fluidizing medium The data used to derive the models cover a wide range of operating conditions, with varying fluidization velocities Effects of static bed height, pal tide diameter, density, tapered angle and superficial gas velocity over minimum fluidization velocity on bed expansion ratios have been investigated experimentally A comparison has been made between the calculated values of bed expansion ratios using proposed models and the experimental data It has been seen that calculated values by models agree well with the experimental values Models have also been compared with literature data of conventional bed and found its applicability at higher gas velocities with good accuracy (C) 2010 Elsevier B V All rights reserved