CFD modelling of gas flow through a fixed bed of Raschig rings

21st Fluid Mechanics Conference

物理学;力学

Marek, M.^1

Institute of Thermal Machinery, Cze¸stochowa University of Technology, al. Armii Krajowej 21, 42-200, Cze¸stochowa, Poland^1

关键词: Cylindrical containers;    Domain geometry;    Geometrical structure;    Grid-independent solutions;    Immersed boundary technique;    Mechanical equilibrium;    Projection method;    Total pressure drop;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/530/1/012016/pdf
DOI  :  10.1088/1742-6596/530/1/012016

学科分类：力学，机械学

来源: IOP

【 摘 要 】

In this work, direct numerical simulation of incompressible gas flow through a complex geometrical structure of Raschig rings is performed. The bed structure is obtained in a separate simulation in which Raschig rings are added one by one and fall freely into a cylindrical container until mechanical equilibrium is reached. The gas is injected at the top of the container, flows through a packed layer of randomly oriented rings, then leaves the container at the bottom. The flow equations are solved with the use of classical second order solver and projection method for structured regular grid and the complexity of domain geometry is handled by a variant of immersed boundary technique. The model allows to study the characteristics of the flow within the bed, pressure distribution in particular, and can be applied to development and validation of simplified approaches. The simulations are performed for various grid resolutions and the results show good convergence to grid independent solution, especially for lower gas velocities. The obtained dependence of total pressure drop on the inlet velocity is in reasonable agreement with the literature data but the demand for grid resolution significantly increases with the gas velocity.