A comprehensive study of the in¯uence of plate geometry and the added packing on the holdup and slip velocity in reciprocating plate columns is presented. The use of packing in the interplate spaces of the column is of interest as packing alters the character of dispersion and also provides contact area for the phases.A model is proposed relating slip velocity to the single drop rise velocity taking into consideration the pseudohydrostatic effects and particle-to-particle interaction effects.
List of symbolsm d 32 Sauter mean drop diameter, m Fr m modi®ed Froude number, U 0X75 d U c Z 1X25 agd o g acceleration due to gravity, m/s 2 Ga Galileo number, d 3 o gq 2 d al 2 d N number of data points P plate spacing, m Re Reynold's number, U s d 32 q c al c Re k Reynold's number based on characteristic velocity, U k d 32 q c al c S fractional plate free area U super®cial velocity of the phase, m/s U k characteristic velocity, m/s U s slip velocity, m/s U t terminal settling velocity, m/s x Parameter Z pulse velocity, m/s a dispersed phase holdup e porosity of packing wpower dissipation, J/m 3 s q density of¯uid phase, kg/m 3 q m average density of the phases q c 1 À a q d a, kgam 3 Dq density difference between the phases q c À q d , kg/m 3 l viscosity of¯uid phase, kg/ms r standard deviation