Study on Gas-Solid Heat Transfer and Flow Characteristics in Packed Beds of Spherical Particles

Three-dimensional pore-scale method is utilized to construct a structured packed bed with spherical particles. Heat transfer between particles is synergistically carried out by conduction and surface radiation. The effects of inlet velocity and packing models (body-centered cubic BCC packing and face-centered cubic FCC packing) on the flow and heat transfer characteristics in a packed bed are thoroughly investigated. The results indicate that the packing structure, temperature, and inlet velocity collectively influence the velocity fluctuations in the packed bed. As the inlet velocity increases, the fluctuation ranges of the gas-solid temperature difference and the flow velocity increase. The Nusselt number, which indicates the intensity of convective heat transfer on the particle surface, exhibits a sudden change near thermal equilibrium. Although the packing form does not significantly affect the heat propagation velocity or the temperature peak, the FCC structure demonstrates relatively more stable gas-solid temperature differences and flow velocity fluctuations compared to the BCC structure, along with superior convective heat transfer performance.