DYNAMIC WAVES IN FLUIDIZED-BEDS

Published results on the velocity of propagation and the change of amp litude of dynamic waves in fluidized beds are reviewed and re-evaluate d. A distinction is drawn between pressure waves and solids concentrat ion waves. Over the range of frequencies of interest in fluidized beds , predictions of the velocity of compression waves by pseudo-homogeneo us models and by models which treat the two phases separately differ l ittle. Therefore the experimental results are compared against the sim pler pseudohomogeneous models. The behaviour of dynamic waves is incon sistent with models which ignore particle-particle contacts. To distin guish unambiguously between compression and dynamic waves, experiments at elevated pressure are needed. The results are not consistent with pseudo-homogeneous description of compression waves.