The movements of silica-alumina particles in a gas fluidized bed of 28 cm I.D. were studied with a modified thermistor probe. The probe developed in this study was found to be able to measure the mass velocity and direction of particle flow in a fluidized bed.
Particles moved upwards near the center of the bed and downwards near the wall. The magnitude of the mass velocity and the cross-sectional area through which the particles move upwards increased with increasing air velocity and position from the bed support.
The profiles of heat transfer coefficient between the surface of a small heating element and the bed were found to be very similar to those of particle velocity, which explains that the heat is transfered mainly by the movements of solid particles and the effect of fluid is minor.