Correction for wall effect in point probe measurements of bubble size

During the measurement of bubble size by a probe inserted into a fluidized bed, parts of some of the bubbles located near the bed boundary are not accessible to the probe. This effect is analyzed theoretically using considerations of geometry and probability and results are given which may be used to correct experimental probe measurements of bubble size for the boundary effect. The procedure is demonstrated using electroresistivity probe measurements taken on a 2 ft-dia. bed of fluidized coke particles.