3-D numerical simulation of the heat transfer of a fluidized bed with a horizontal tube bundle and Geldart D particles

Abstract

In the present study, a numerical simulation is performed to analyse hydrodynamic and heat transfer of a fluidized bed in a vertical channel. As a novelty, MP−PIC method is applied to 3-D tube bundles immersed in a fluidized bed with Geldart D particles. The main results are compared and validated using the experimental results published in the literature.In both tube bundle distributions, the lowest heat transfer coefficients were obtained in the top region of the tube, which represents approximately 58% of the time average heat transfer coefficient of the surface tube. This behaviour differs at the bottom and sides, where particles are continuously being replaced by other particles, resulting in low particle volume fractions and higher heat transfer coefficients.Analysing each tube arrangement for the cases with the same gas velocity and particle diameter, the results numerically obtained were consistent with the experimental findings. The present study found that the time average heat transfer coefficient for the staggered arrangement was approximately 6%, 5% and 1.6% higher than that in-line, for the particle diameter of 1400, 1600 and 1850 μm, respectively. Some discrepancies can be highlighted when comparing the experimentally and numerically obtained time average heat transfer coefficients, with maximum differences close to 18%, which correspond to the cases with the highest gas velocity and particle diameter (1.71 m/s, 1850 μm).