The effect of operating conditions (base angle, gas inlet diameter,stagnant
bed height, particle diameter, and gas velocity) on longitudinal, and radi
al profiles of bed voidage has been studied in the spout, annulus, and both
the fountain core and periphery of spouted beds, by means of an optical fi
ber probe. Correlations are proposed for calculation of the local bed voida
ge in spout and annular zones, along the spout axis and in proximity to the
contactor wall.