Numerical analysis of heat transfer characteristics of thermally thick particles in a fluidized bed

To address the limitations of isothermal models in accurately predicting heat transfer in thermally thick particles (Bi > 1) and to establish a theoretical basis for optimizing fluidized bed reactors used in carbon emission reduction technologies, this study investigates the heat transfer characteristics of such particles, with particular emphasis on the role of internal particle conduction. Based on the CFD-DEM framework, a one-dimensional heat conduction model for the intra-particle temperature is developed. The model is first validated against single-particle and system-level experiments to ensure its accuracy. Subsequently, the effects of particle thermal conductivity and diameter on temperature distribution and heating process are analyzed. The results indicate that increasing the thermal conductivity reduces the maximum internal temperature difference from 300.99 K to 64.67 K and shortens the heating time from 11.19 s to 7.13 s. Similarly, reducing the particle diameter decreases the internal temperature difference peak from 223.7 K to 94.18 K and reduces the heating time from 11.25 s to 5.76 s. However, it also leads to greater temperature non-uniformity during the initial heating stage. These findings enhance the understanding of heat transfer behavior in thermally thick particles within fluidized bed reactors.