Numerical prediction of Péclet number in small-sized fixed bed reactors of spheres

Abstract Fluid dispersion in small fixed bed reactors under single phase laminar flow conditions is evaluated through accurate predictions of axial Peclet numbers Peax using Direct Numerical Simulations (DNS). The fixed bed packing is obtained through the Discrete Element Method (DEM) code Grains3D. Peax numbers are computed from steady state simulations of the flow. An additional set of equations solving the spatial distribution of the moments of the age distribution is used. This gives access to local information on dead zones or bypasses. Computations are realized with the OpenFOAM® open-source library. Results are close to the experimental data. The DEM-OpenFOAM® workflow benefits from an accurate control of the fluid physical properties and packing geometry, thus leading to a faster production of data than an experimental approach. We first explore the influence of the reactor-to-sphere diameter ratio δ (δ