In gas fluidization processes involving different types of particles, the mixing or segregation behavior of the solid mixture is crucial to the overall outcome of the process. This study develops a model to predict the segregation directions of binary mixtures of Geldart B particles with density and size differences in bubbling fluidized beds. The proposed model was established by combining the particle segregation model, a previous particle segregation model, with a derived bed voidage equation of the bubbling fluidization based on the two-phase theory. The model was then analyzed with different function graphs of the model equations under various conditions. The results indicated that an increase in gas velocity or volume fraction of larger particles would strengthen size segregation, causing the larger and less dense components to descend. To validate the model, 42 sets of data collected from 6 independent literature sources were compared with the predictions of the model. When the gas velocities were below 3.2 times the minimum gas velocity, the predictions were consistent with experimental results. This study has shed new light on the mechanisms of particle segregation in binary fluidized systems and provides a theoretical foundation for designing and manipulating gas-solid fluidized reactors.

中文翻译：

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预测鼓泡流化床中二元 Geldart B 颗粒混合物偏析方向的模型

在涉及不同类型颗粒的气体流化过程中，固体混合物的混合或分离行为对于过程的整体结果至关重要。本研究开发了一个模型来预测鼓泡流化床中具有密度和尺寸差异的 Geldart B 颗粒二元混合物的偏析方向。该模型是通过将颗粒偏析模型（先前的颗粒偏析模型）与基于两相理论推导的鼓泡流化床空隙度方程相结合而建立的。然后在不同条件下使用模型方程的不同函数图对模型进行分析。结果表明，气体速度或较大颗粒体积分数的增加会加强尺寸偏析，导致较大和密度较小的组分下降。为了验证模型，将从 6 个独立文献来源收集的 42 组数据与模型的预测进行了比较。当气体速度低于最小气体速度的3.2倍时，预测结果与实验结果一致。这项研究为二元流化系统中颗粒分离的机制提供了新的线索，并为设计和操作气固流化反应器提供了理论基础。