Eulerian formulation for the triboelectric charging of polydisperse powder flows

TL;DR

This paper introduces a novel Eulerian model for simulating triboelectric charging in polydisperse powder flows, capturing complex particle size distributions and charge interactions in a comprehensive continuum framework.

Contribution

It presents the first Eulerian formulation capable of modeling polydisperse powder flows with charge exchange and electrostatic effects, advancing beyond previous monodisperse or bidisperse models.

Findings

The model predicts charge distribution in channel flows from walls to center.

It demonstrates the impact of particle size and initial velocity on charging.

The approach can simulate real powder flow charge build-up in industrial settings.

Abstract

We propose an Eulerian formulation for the triboelectric charging of powder flows. Recently, continuum descriptions of the charging of monodisperse and bidisperse powder appeared. Now, we propose the first Eulerian formulation for this type of flows that can fully account for polydisperse particle size distributions. To this end, the joint particle size, velocity, and charge distribution function is solved through the direct quadrature method of moments. The newly established approach includes the uptake of electrostatic charge by the particles when contacting a solid wall and the exchange of charge in-between particles during collisions. The electrostatic field induced by the charge of the particles and the drag forces of the surrounding gas affect the particle dynamics. Test cases of two-dimensional steady channel flows demonstrate the charging of the flow from the walls towards the center and in downstream direction. Further, the method predicts the effect of variations of the particle size and initial velocity distribution and the charge diffusion coefficient. The ability to handle polydispersity is a step towards the simulation of the electric charge build-up of real powder flows in full-scale technical applications.