Résumé
Random packed beds of cylindrical, trilobic, and quadrilobic particles in cylindrical and biperiodic containers are numerically studied using Grains3D, a code based on the discrete element method (DEM) that resolves all inelastic collisions and dynamically simulates the loading of packed beds. Particle initial position and orientation are random to mimic industrial or laboratory packing procedures, so that the same simulation repeated again yields a different packed bed structure and thus a different average void fraction. These ”in silico” experiments aim at being able to optimize particle shape in heterogeneous catalysis, in particular with respect to the corresponding bed void fraction that is a critical parameter for pressure drop prediction. These “in silico” experiments are deterministic and accurate but with differences due to the loading procedure. In this paper, we first present our assessment of the uncertainty on average void fraction induced by (i) the initial random position and orientation of inserted particles and (ii) the insertion zone size. Next we investigate the effect of particle shape, namely cylindrical, trilobic, and quadrilobic on the average void fraction as a function of particle length and diameter, and of the container type. Simple correlations are proposed that very well describe the simulations within the aforementioned uncertainty related to the packing procedure. Although the beds made with cylindrical particles are markedly denser, the beds made of the trilobic and quadrilobic particles have a statistically identical void fraction.