Large-eddy simulation for particle collision growth in turbulent flows

Abstract

The collision frequency of inertia particles in turbulent flows is governed by a wide range of scales of flow motion. Recent studies have shown that large-scale energetic eddies dominate the relative velocity between two colliding particles (the turbulent transport effect), whereas small-scale dissipative eddies can enhance the collision frequency significantly by inducing local non-uniform particle distribution (the accumulation effect). In this study, we have developed an integrated collision kernel model, which takes into account both the turbulence effects and can predict collision frequencies at arbitrary Reynolds numbers and particle inertia. In addition, we have implemented the developed collision kernel model into a large-eddy simulation (LES). We have performed our developed LES for particle collision growth in an isotropic evolving turbulence. A direct numerical simulation (DNS) for the same system has also been done. Comparison between our LES and DNS predictions has confirmed that our LES can predict the particle collision growth in the turbulent flow.