Eulerian modelling of gas-solid flows with triboelectric charging

Particles subjected to flow are known to acquire electrostatic charges through repeated contacts with each other and with other surfaces. These charges alter gas-particle flow behaviour at different scales. In this work, we present a continuum framework for analysing the interplay between tribocharging and the flow of a monodisperse assembly of particles characterized by a single effective work function. Specifically, we have derived the continuum, kinetic theory transport equations for gas-particle flow and local-averaged charge on particles directly from the Boltzmann equation. We also derive the auxiliary conditions to capture tribocharging at bounding conducting walls. The resulting two-fluid model with tribocharging and boundary conditions has then been validated against results from discrete element simulations that have been specially designed to probe specific terms in the models.