In a dense gas–solid fluidized bed, the microscopic quantities, including forces and energy of particles, directly determine their macroscopic motion in space. In this work, the CFD–DEM coupling approach is used to detect the energy evolution and the effect of fluid forces on the particles using a microscopic perspective. The numerical simulation accuracy of CFD–DEM to predict the macroscopic motion behavior of the particles was validated by carrying out high-speed photographic tests. The results showed that the drag force positively correlates with the inlet flow rate and particle diameter, where it exists only near the inlet. In the axial position of the fluidized bed near the inlet, the tangential contact force is significantly dominant, while an effect of a small proportion of particles with a normal contact force (> 0.1N) is founded. Under different operating conditions, the fluid pressure gradient force can be neglected at a position greater than two times the inlet length where a convex curve shape is formed. In addition, the particle energy is positively correlated with the inlet flow rate and the particle diameter, where the existing bubble formation causes energy fluctuations. This study reveals the microscopic mechanism of gas–solid interaction and provides theoretical guidance for the optimal design of fluidized bed structure and improvement of mathematical models.

在致密气固流化床中，粒子的力和能量等微观量直接决定了它们在空间中的宏观运动。在这项工作中，CFD-DEM 耦合方法用于从微观角度检测能量演化和流体力对颗粒的影响。通过进行高速摄影测试，验证了 CFD-DEM 预测颗粒宏观运动行为的数值模拟精度。结果表明，阻力与入口流量和颗粒直径呈正相关，仅存在于入口附近。在靠近入口的流化床的轴向位置，切向接触力显着占主导地位，同时发现少量具有法向接触力（> 0.1N）的颗粒的影响。在不同工况下，在大于入口长度两倍、形成凸曲线形状的位置处，流体压力梯度力可以忽略不计。此外，颗粒能量与入口流量和颗粒直径呈正相关，其中存在的气泡形成导致能量波动。该研究揭示了气固相互作用的微观机制，为流化床结构的优化设计和数学模型的改进提供理论指导。