Agglomeration and Collision Behaviour of Non-Spherical Particles in Turbulence

Non-spherical particle-particle interactions are studied under the influence of a fully resolved turbulent flow field and particle-fluid coupling, obtained through direct numerical simulation and an immersed boundary method. Agglomeration outcomes are accommodated through the incorporation of attractive van der Waals forces under the DLVO framework, suitably adapted to consider the orientational dependencies associated with non-spherical shape. Binary interactions take place in both quiescent conditions, as well as a periodic box of homogeneous, isotropic turbulence, maintained using a stochastic forcing method, with properties matching those observed in the viscous sublayer of a shear Reynolds Reτ = 180 channel flow. Differences in particle interaction behaviours are presented for the case of disks and needles, with the role of orientation and velocity in determining interaction outcomes assessed. Results indicate that the inclusion of DLVO forces promotes alignment between the symmetry axes of spheroidal particle pairs, whilst turbulence promotes an increased alignment between interacting particles.