Simultaneous measurement of phase velocities in dispersed two-phase hows ha
s been carried out using a laser Doppler velocimeter. For this purpose, axi
al and radial components of instantaneous velocity and the cross-correlatio
n of these two components were measured. The dispersed phase has been isola
ted on the basis of threshold values of crosscorrelation. The method accura
tely predicts the number, size, and slip velocity of the dispersed phase (b
ubbles and particles) in dilute dispersions. In dense gas-liquid dispersion
s, a procedure has been given for the estimation of local fractional gas ho
ld-up and the individual phase velocities.