Influence of immersed surface shape on the heat transfer process and flow pattern in a fluidized bed using numerical simulation.

Abstract This paper presents a 2-D numerical simulation of a freely bubbling fluidized bed with immersed surfaces, using the Computational Particle Fluid Dynamics ( C P F D ) model implemented in the Barracuda commercial software. The heat transfer coefficients obtained are compared with an experimental study available in the open literature and numerical simulations based on the two-fluid model approach performed by other authors. Two different immersed surfaces, representing spherical and cylindrical geometries were studied. The simulations results show different heat transfer mechanisms, depending on the angular position in the two immersed surface geometries studied. The time average heat transfer coefficient around the whole heat transfer surface were 25 % and 38 % lower than the experimental study, for the cylindrical and spherical surfaces, respectively. These differences are lower than the results obtained with the two-fluid model approach reported in the open literature. The numerical results indicate that CPFD-Barracuda is able to properly simulate the heat transfer and the dynamics of the bed in defluidized regions, such as on the top of an immersed surface, where the two-fluid model fails and overpredicts the heat transfer rate.