Development of a filtered drag model considering effect of the solid shear rate

This study investigates a 2D gas–solid fast fluidized bed of typical Geldart A particles using highly resolved simulations with two-fluid model. The results show that the solid shear rate has a considerable impact on the orientation of the meso-scale structures and hence on the filtered drag force. On the basis of the correlation for the filtered drag force established in the literature using the traditional markers (such as filtered solid volume fraction, filtered slip velocity and filter scale), a correction correlated with the solid shear rate in the direction of gravity is proposed for better prediction of the filtered drag force. The corrected model is shown to produce improved results in posterior tests of flows in different fluidization regimes including bubbling, turbulent and fast fluidization.

本研究采用双流体模型（two-fluid model）开展高分辨率数值模拟，针对典型盖尔达特A类颗粒（Geldart A particles）组成的二维气固快速流化床展开研究。结果表明，固相剪切速率对介尺度结构的取向具有显著影响，进而作用于过滤曳力。基于现有文献中以传统表征参数（如过滤固相体积分数、过滤滑移速度及过滤尺度）构建的过滤曳力关联式，本研究提出了与重力方向上固相剪切速率相关的修正项，以实现过滤曳力的更精准预测。经后验测试验证，该修正模型在鼓泡流化、湍流流化及快速流化等不同流化工况下均展现出更优的预测性能。