Bed symmetry in the fountain confined conical spouted beds with open-sided draft tubes

Bed symmetry has been analysed in fountain confined conical spouted beds operating with fine particles. Thus, vertical particle velocities and the spout shape have been determined in a wide range of spouting air velocities and bed configurations. Bed symmetry is widely accepted in the spouted beds without draft tubes or with nonporous ones, but this is not the case when open-sided draft tubes are used. Thus, radial particle velocity profiles differ depending on the cross-sectional angular plane considered in the open-sided draft tubes. The spout expands preferentially along the tube opened surface, and is wider as spouting air velocity and aperture ratio are increased. The literature correlations proposed for the average spout diameter have been analysed and no one is valid for estimating this parameter in the whole range of spouting air velocities and configurations analysed in these systems operating with fine particles. This work has received funding from Spain's Ministry of Science and Innovation (PID2019-107357RB-I00 (AEI/FEDER, UE)), the Basque Gov- ernment (IT1218–19 and KK-2020/00107) and the European Commis- sion (HORIZON H2020-MSCA RISE-2018. Contract No.: 823745). M. Tellabide thanks Spain's Ministry of Education, Culture and Sport for his Ph.D. grant (FPU14/05814). I. Estiati thanks the University of the Basque Country for her postgraduate grant (ESPDOC18/14).