Development and Validation of a Binary Collision Detection Algorithm for a Polydispersed Particle Mixture

Abstract

A time driven Lagrangian particle detection algorithm for a poly-dispersed mixture of particles is developed and validated. The advantage of this algorithm is the possibility to treat a distribution of particle diameters. We are especially interested in the collision treatment of poly-dispersed particle mixtures and coalescence. Particle pairs are found by applying the overlap criteria and additionally another second criterion, which allows a substantial increase of the time step without limiting the algorithm’s accuracy. The algorithm, which is developed here, is validated with test cases by comparison with predictions of the kinetic theory of rarefied gases. They are applied to dry granular flows. The algorithm accuracy is determined with respect to time step criteria, for both dilute and dense systems.

Monte-Carlo simulation of colliding particles or coalescing droplets transported by a turbulent flow in the framework of a joint fluid–particle pdf approach

“…Such an algorithm may reduce the computation cost to Oð124N p Þ. For polydisperse particle mixtures and coalescence of droplets Wunsch et al (2008) proposed and implemented a collision detection algorithm which was used in this work. More details can be found in Wunsch et al (2010a).…”

“…This configuration of an homogeneous isotropic flow with colliding particles has been extensively investigated by DPS/DNS or DPS/LES (Deutsch and Simonin, 1991;Laviéville et al, 1997;Février et al, 2005;Wunsch et al, 2008;Fede and Simonin, 2010). The methods and the equations solved are briefly given in Appendix A.…”

Efficient simulation of particle-laden turbulent flows with high mass loadings using LES

“…Especially for dense flows it is therefore advantageous to neglect the displacement during the collisions. Some alteration of the statistical results in non-homogeneous flows has to be expected by this simplification (Wunsch et al, 2008). However, owing to the small time step sizes applied in LES, the error is assumed to be marginal.…”

“…The reason why the displacements are preferred to be neglected after the collisions, are discussed in detail in Wunsch et al (2008). Displacing the two participating particles after its collision harbors the inherent risk that an overlap with a third particle is generated.…”

“…1a). The method is commonly employed in molecular dynamics or smooth particle hydrodynamics (see, e.g., Viccione et al, 2008), for the simulation of granular flows (see, e.g., Hopkins and Louge, 1991) but also for multiphase flows (see, e.g., Wunsch et al, 2008) restricting the collision detection on neighboring particles within a virtual cell. Choosing the cell size in such a way that the number of particles per cell is sufficiently low, the cost of checking collisions is reduced from the order OðN 2 p Þ to O(N p ), which is crucial for large numbers of particles, e.g., N p = O(10 7 -10 8 ) at high mass loadings.…”