Abstract
To diagnose the processes causing metal wastage from immersed surfaces in fluidized beds, a miniaturized probe was developed for simultaneous measurement of the transient normal and tangential components of particle velocity and stress against a surface. In a two-dimensional bed, high shear stresses are generated by oblique impact of particles in bubble wakes. The associated particle velocities correspond closely with estimates from video records, and are consistent with current understanding of particle motion in fluidized beds. Taken together, the results suggest that metal wastage results from a combination of impact and abrasion. (A)