发表机构
School of Mechanical and Materials Engineering, Indian Institute of Technology Mandi（印度曼迪理工学院机械与材料工程学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过CFD-DEM模拟比较水和空气作为流化介质对二元流化床的影响，发现归一化速度下空气流化导致更大膨胀和更强混合，而水流化床更均匀，表明流体性质显著影响颗粒输运机制。
AI 中文摘要
采用三维CFD-DEM模拟研究了流化介质对包含等密度3毫米和4毫米颗粒的二元流化床水动力学和混合的影响。在匹配的归一化表观速度（最小流化速度的0.5至3.0倍）下，使用相同的几何结构、颗粒特性和初始条件对水和空气进行了比较。数值框架已针对已发表的液固床膨胀数据进行了验证，并与已建立的气固CFD-DEM案例进行了基准测试。在匹配的归一化表观速度下，水流化产生了相对致密且均匀的床层，床层高度和压降稳定，速度波动较弱。空气流化导致更大的膨胀、持续振荡、空隙和气泡状结构、更强的循环以及更大的空间异质性。使用Lacey混合指数量化的混合程度在两种介质中均随表观速度增加而增加，但在空气中发展更快且达到更高水平。颗粒轨迹和均方位移进一步表明空气中颗粒迁移率和输运更大。结果表明，按最小流化速度归一化并不能统一不同流化介质的水动力学或混合行为，因为流体性质强烈影响底层颗粒输运机制。
英文摘要
Three-dimensional CFD-DEM simulations were used to investigate the influence of fluidizing medium on the hydrodynamics and mixing of a binary fluidized bed containing equal-density 3 and 4 mm particles. Water and air were compared using identical geometry, particle properties, and initial conditions over matched normalized superficial velocities of 0.5-3.0 times the minimum fluidization velocity. The numerical framework was validated against published liquid-solid bed-expansion data and benchmarked against an established gas-solid CFD-DEM case. At matched normalized superficial velocities, water fluidization produced a comparatively dense and homogeneous bed with stable bed height and pressure drop and weak velocity fluctuations. Air fluidization resulted in greater expansion, persistent oscillations, void- and bubble-like structures, stronger circulation, and greater spatial heterogeneity. Mixing, quantified using the Lacey mixing index, increased with superficial velocity in both media but developed more rapidly and reached higher levels in air. Particle trajectories and mean-square displacement further showed greater particle mobility and transport in air. The results demonstrate that normalization by the minimum fluidization velocity does not collapse the hydrodynamic or mixing behavior across fluidizing media because fluid properties strongly influence the underlying particle-transport mechanisms.
Comments20 pages, 24 figures
