Journal
JOURNAL OF FLUID MECHANICS
Volume 818, Issue -, Pages 465-491Publisher
CAMBRIDGE UNIV PRESS
DOI: 10.1017/jfm.2017.157
Keywords
MHD and electrohydrodynamics; particle/fluid flow; turbulent flows
Categories
Funding
- National Research Fund of Belgium (FNRS) under the GRANMIX Projet de Recherche grant
Ask authors/readers for more resources
The electrification of particles embedded in a turbulent flow may cause hazards such as spark discharges but is also exploited in several industrial applications. Nonetheless, due to its complexity and sensitivity to the initial conditions, the process of build-up of particle charge is currently not well understood. In order to gain a deeper understanding of this phenomenon, we performed fully resolved numerical simulations of particle charging. More specifically, our study concerned the charging process of particles dispersed in a turbulent channel flow at a friction Reynolds number of Re-tau = 180. Emphasis was placed on the analysis of the interplay between the different physical mechanisms underlying particle electrification, such as fluid turbulence, particle dynamics and particle collisions. Further, we investigated the influence of some important physical parameters. According to our simulations the charge build-up depends strongly on the particle Stokes number, Stk. In particular, at small Stokes numbers, Stk = 0.2, the turbopheretic drift inhibits particle charging. By contrast, at moderate Stokes numbers, Stk = 2, and low particle number densities, the electric charge builds up but cannot escape the viscous sublayer due to limited particle migration. However, in the case of high particle number densities, the charge is transported away from the wall via inter-particle charge diffusion. A further increase to Stk = 20 leads to strong charging and particle-bound charge transport towards the bulk of the channel.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available