CFD investigation of particle fluctuation characteristics of bidisperse mixture in a gas–solid fluidized bed
CFD investigation of particle fluctuation characteristics of bidisperse mixture in a gas–solid fluidized bed
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DOI：
10.1016/j.ces.2012.07.022
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发表时间：
2012-09
影响因子：
4.7
通讯作者：
Jingyuan Sun-;Jingdai Wang;Yongrong Yang
中科院分区：
文献类型：
--
作者：
Jingyuan Sun-;Jingdai Wang;Yongrong Yang
采用多流体欧拉-欧拉模型对气固流化床内双分散混合物的颗粒脉动特性进行了CFD模拟。数值计算方法得到了固相体积分数和颗粒温度实验数据的验证。结合流化床内气泡和颗粒的流体力学行为及流型，计算了不同气速下漂浮物和抛弃物的层流和湍流颗粒温度分布。通过计算得到的漂浮物和抛投物垂向湍动能谱的比较，揭示了颗粒运动强度和湍动能耗散的不均匀性。能谱在高频率惯性范围内符合Levy-Kolmogorov定律。给出了颗粒脉动速度小波分解系数的平坦因子，分析了流场脉动速度随位置和气速的变化。此外，还计算了漂浮物和废弃物的扩散系数，以衡量颗粒的传质质量。
Particle fluctuation characteristics of a bidisperse mixture in a gas–solid fluidized bed by the multi-fluid Eulerian–Eulerian model in CFD simulation have been presented. The numerical method is verified by solid volume fraction and granular temperature experimental data from literature. The laminar and turbulent granular temperature profiles of flotsam and jetsam at different gas velocities are calculated, connecting with bubble and particle hydrodynamic behavior and flow pattern in the fluidized bed. The computed vertical turbulent energy spectra of flotsam and jetsam are compared and applied to indicate the particle motion intensity and inhomogeneity of turbulent energy dissipation. The energy spectra capture the Levy–Kolmogorov law in inertial range at high frequency. The flatness factor of wavelet decomposition coefficients of particle fluctuating velocity is shown to analyze the flow field intermittence variation with position and gas velocity. Moreover, the diffusivities for flotsam and jetsam are calculated to measure the mass transfer quality of particles.