THE DEPENDENCE OF AXIAL-DISPERSION ON NONUNIFORM FLOWS IN BEDS OF UNIFORM PACKING

Axial dispersion in packed beds in analyzed using both the dispersed plug flow model and a nonplug flow model which has been previously used successfully to treat dispersion in laminar and turbulent flow in tubes. The velocity profiles required for predicting dispersion with the nonplug flow model was based on a modified Navier-Stokes equation to account for the resistance of the packing to flow. This term allows radial variations in void fraction and predicts their effect on the velocity profile. Numerical solution of the flow model allows the prediction of dispersion coefficients for flow in packed beds. Experimental results obtained in this study compare favorably with predicted values and with dispersion data available in the literature. © 1990.