Relationship Between Characteristics Of Packed Bed Structure And Fluid Flow

The application of packed beds reactor in the chemical industry is widespread.The flow state of the fluid in the beds has an important influence on mass,momentum and heat transfer processes,which directly affects the reaction efficiency.And the fluid flow in the packed bed is closely related to the pore structure of the packed beds.Therefore,understanding the relationship between these two effects has important implications for improving the reaction efficiency,the quality of products,and for reducing risks.In the present study,the Voronoi method had been used to study the structure of packed beds,which were generated by means of the discrete element method(DEM),and a three-dimensional nineteen-velocity(D3Q19)lattice model,deriving from Lattice Boltzmann Method(LBM),was used to simulate the single-phase flow in packed beds.The analysis of the space around the particles and the fluid flow velocity in this space shows that the bed flow velocity is closely related to the size of the space around the particle.The larger the space is,the greater the velocity and the easier the reverse flow.The Voronoi method was used to investigate the distribution of the pore diameter in these randomly packed beds.Combining with the flow velocity characteristics in the pores,the pores in those beds were classified into three levels,which are micropores,mesoporous,and macropores.