A 20 cm diameter semi-cylindrical spout-fluid bed with a draft tube has been used to study the effects of operating and geometric parameters on the solids circulation rates at ambient temperature. A new technique has been developed for measuring the solids fluxes with great accuracy. Solids circulation rate data have been found to be strongly influenced by both geometry and relative magnitude of spouting and auxiliary gas flowrates, as they in turn affect the flow of the gas-solid mixture inside the draft tube. The solids circulation rate was greatly enhanced when an auxiliary flow aerated the annular region and such enhancement has been found to be linearly dependent on the auxiliary flow contribution to the total gas flow and on the distance between the base of the draft tube and the inlet nozzle.
On a utilise un lit fluide a jaillissement semi-cylindrique de 20 cm de diarnetre muni d'un tube de circulation pour Ctudier les effets des parametres operatoires et geometriques sur les vitesses de circulation des solides a la temperature arnbiante. Une nouvelle technique a ete mise au point pour mesurer les flux de solides avec un grande exactitude. On a trouve que les donnees de vitesse de circulation des solides sont fortement influencees a la fois par la geometrie et la grandeur relative du jaillissement et des debits gazeau auxiliaires, du fait que ceux-ci modifient a leur tour l'ecoulement du melange gaz-solides a l'interieur du tube de circulation. La vitesse de circulation des solides est largement amelioree lorsqu'un ecouleinent auxiliaire aere la region annulaire et on a trouve que cette amelioration est lineairement dependante de la contribution de l'ecoulement auxiliaire au debit gazeau total et de la distance entre la base du tube de circulation et de la tuyere d'entree.
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