Numerical simulation of a gas flow in a real geometry of random packed bed of Raschig rings

- A method is proposed for simulation of laminar flows in a random packed bed of arbitrary particles.
- The method can be used with a finite volume solver for regular Cartesian grids.
- The method is demonstrated in a single-phase flow simulation using a real geometry of a bed of Raschig rings.
- Pressure drop calculations are in a good agreement with empirical correlations.

In the article, a model is proposed for a single-phase flow in a random packed bed of arbitrary particles - Raschig rings in particular. The Navier-Stokes flow equations are solved using a projection method on a structured grid and the complex geometry of the bed is captured with the immersed boundary method and direct forcing approach. The model allows for analysis of flows in complex geometries with classical and widely available finite volume or finite difference solvers for Cartesian grids. The generation of unstructured computational grids fitted to the bed particles is not necessary. The realistic bed geometry has been obtained in the simulation of the filling process in which the particles are sequentially introduced into a cylindrical container and move until mechanical equilibrium is attained. The pressure drop in the bed as the function of gas velocity has been found to be in good agreement with empirical formulas for beds of Raschig rings and sample results on detailed flow characteristics are presented.

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