Analysis of the variables controlling gas jet expansion angles in fluidized beds

The expansion angle  of gas jets issuing in fluidized beds is one of the parameters necessary for the application of hydrodynamic models of the jet region. A limited body of exptl. data is available in the literature so that a method of prediction is still lacking. The phenomena assocd. with the formation of a jet above an upward gas discharging nozzle in a fluidized bed were analyzed with particular ref. to the influence that the operating variables and the geometric configuration have on . The anal. allowed the relevant variables concerned with these phenomena to be found and their connection with the dynamic features of the jet and of the bed, contrasting with the current viewpoint that considers  as a parameter dependent only on the static characteristics of the system. The dimensional anal. yielded a set of relevant dimensionless groups among which the two-phase Froude no. provides a good correlation of most of the literature data.