Wall to bed heat transfer in liquid soli

Wall-to-bed heat transfer in gas-liquid-solid fluidized beds with cocurrent upflow was analyzed based on a series thermal resistance model. This study aimed to determine the effective radial thermal conductivity and the apparent wall heat transfer coefficient under various experimental conditions. The results demonstrated that the behavior of the effective thermal conductivity depends significantly on the flow mode of the three-phase fluidized bed, indicating the radial liquid mixing trend. Furthermore, the modified Peclet number for radial thermal diffusivity revealed a minimum concerning liquid velocity, resembling the behavior observed in liquid-solid fluidized beds, though the modified Peclet number markedly decreased with increasing gas velocity. Additionally, the apparent wall heat transfer coefficient correlated well with a Colburn-type equation, which reduced to the same equation proposed for liquid-solid fluidization at zero gas velocity. These findings contribute to a better understanding of heat transfer in complex fluidized bed systems and may enhance the modeling of such systems in various chemical engineering applications.