Indirect Method of Measuring Dispersion Coefficients for Granular Flow in a Column of Dihedrons

摘要

In the chemical, pharmaceutical and food-processing industries, the drying operation is a majornintermediate step in the production of finished or semi-finished products. There are a greatnmany drying processes and types of equipment, such as dryers with immersed channels; the mainnadvantage of this type of dryer is the homogeneous distribution of the drying air, made possiblenby dihedrons, a special device for introducing the air. The basis tool for dimension, a drier withnimmersed channels, is the control of the dehydration of the product, and the distribution functionnresidence time of the particles inside the column. In the present study, a model and thus an indirectnmeasurement of dispersion coefficients of solids were proposed in contrast with previousnstudies where the variation of dispersion coefficient has often been disregarded in the granularnflow models. The comparison of calculations with measurements gave an indirect measurementnof the longitudinal and transversal variable coefficients as a function of the position in the column.nIt is concluded that it is necessary to account for the variation of dispersion coefficients during thengranular flow in the column to obtain a correct description of their flow. It is worth noting that thisnindirect measurement proves that the transversal dispersion coefficient varied much more than thenlongitudinal one.