CFD simulation of dynamic characteristics in liquid-solid fluidized beds
CFD simulation of dynamic characteristics in liquid-solid fluidized beds
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DOI：
10.1016/j.powtec.2012.01.030
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发表时间：
2012-09
影响因子：
5.2
通讯作者：
Kai Zhang;Guiying Wu;S. Brandani;Honggang Chen;Yongping Yang
中科院分区：
文献类型：
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作者：
Kai Zhang;Guiying Wu;S. Brandani;Honggang Chen;Yongping Yang
采用一个简单的双流体模型来预测液速阶跃变化后的液固流态化流体力学。该模型在Gidaspow（1994）的无粘模型A的基础上，考虑了颗粒弥散对动量方程的影响。数值模拟是在CFX4.4平台上进行的，CFX4.4是一个商业CFD代码，与用户定义的FORTRAN子程序一起。在这项工作中预测的总床层空隙率比文献中基于颗粒流动力学理论的空隙率更接近实验测量（Cornelissen等人，2007年）。结果表明，膨胀过程中除过渡阶段外，计算床高与理想曲线拟合较好，导致实际响应时间略大于其相应的理想值。非均速入口条件对床内瞬态固相体积分数和床面响应时间有很大影响。然而，在收缩过程中，瞬态床层高度和响应时间完全遵循均匀或波形液体入口条件的理想预测。
A simple two-fluid model is used to predict the hydrodynamics of liquid–solid fluidization after a step change in liquid velocity. Based on the inviscid model A of Gidaspow (1994), the effect of the particles dispersed on the momentum equations is considered in this model. Numerical simulations are conducted in the platform of CFX 4.4, a commercial CFD code, together with user-defined FORTRAN subroutines. Predicted overall bed voidage in this work is much closer to the experimental measurement than that based on the kinetic theory of granular flow in the literature (Cornelissen et al., 2007). The results show that the computational bed heights in the expansion process fit in with the idealized curve except at the transitional stage, which leads to actual response time slightly greater than its corresponding idealized value. Non-uniform liquid velocity inlet condition has a strong effect on the transient solid volume fraction within the bed and the response time of bed surface. In the contraction process, however, the transient bed height and response time follow exactly the idealized predictions for either uniform or wave-shaped liquid inlet condition.