A network model and numerical simulations of flow distributions in packed bed reactors with different packing structures

摘要

Due to the high specific surface area, packed bed reactors are widely used in real engineering applications. The flow distribution, which is highly dependent on the packing structure, can be vital for the heat/mass transfer and reaction performances. This makes the study of the flow distribution in packed beds quite important. In the present paper, an equivalent network model based on the Voronoi tessellation is proposed to predict the flow field. In addition, a relationship between the hydraulic resistance and the pore structure is introduced. Besides, the influence of the packing structure on the flow distribution is discussed. Numerical simulations using ANSYS FLUENT are also carried out to check the reliability of the network model. It is found that firstly, the proposed correlation of hydraulic resistance can capture the flow characteristics with high accuracy and the flow distributions predicted by the network model fit well with the simulation results for 2-D ordered packing structures with mono-sized and dual-sized particles and disordered packing structures with mono-sized particles. Secondly, it is revealed that, the packing form and the pore dimension have a significant effect on the flow distribution. Thirdly, the flow rate in a certain channel is dependent on the hydraulic resistances of the adjacent channels rather than just on itself.