Numerical study on the wall to bed heat transfer in a conical fluidized bed combustor

In this work a numerical investigation of wall to bed heat transfer, and the related flow characteristics, was conducted along a conical fluidized bed combustor with a height of 0.8 m and a cone angle of 30°. A two-fluid Eulerian-Eulerian model was used while applying Kinetic Theory for Granular Flow (KTGF) to a wall-to-bed FB reactor. The heat transfer coefficient and hydrodynamics are discussed for two different drag models, namely the Gidaspow and Syamlal-O’Brien models. Furthermore, computational calculations were carried out for a variety of inlet velocities(1.4U_mf~4 U_mf) and different particle sizes. The heat transfer coefficient in the bed region was evaluated and compared with that calculated by penetration theory. The bed expansion for the two models was compared with that calculated using correlations from literature in order to validate the numerical calculations. The heat transfer coefficient was found to be increasing with increasing gas velocity and decreasing with increasing particle diameter.