Role of Geometrical Parameters on Heat Transfer in Liquid-Solid Fluidized Beds

A numerical investigation of hydrodynamic and heat transfer characteristics in liquid-solid fluidized beds was conducted using a coupled CFD-DEM approach combined with a thermal model. Simulations were carried out for a range of particle and column diameters with varying inlet fluid velocities under isothermal wall boundary conditions. The model was capable of simulating the simultaneous effects of conductive particle-particle heat transfer and convective particle-fluid heat transfer. The accuracy of the coupled model was established by validating the results against experimental data in the literature on hydrodynamic characteristics and thermal behavior. It has been observed that the results obtained from the CFD-DEM simulation have a good agreement with the experimental data, and the average deviation is within the range of 6-8%. From the results, it was evident that the smaller particles improved the heat transfer performance. Enhancements of convective heat transfer and a decrease of temperature gradients in the bed with increasing inlet fluid velocity were found, especially in the column with the wider diameter. Results from the simulations elucidated the conductive heat transfer through contacts between particles as well as the convective heat transfer between fluid and particles, and showed that the interplay between particle size, column diameter, and fluid velocity determines the performance of heat transfer. The novelty in this research is the quantification of conduction and convection heat transfer interactions using a fully resolved CFD-DEM model for heat transfer. This research also gives practical guidelines on how to improve heat transfer in liquid-solid fluidized.