[Paper Review] Effect of Reynolds number on triboelectric particle charging in turbulent channel flow

Christoph Wilms, Holger Grosshans|arXiv (Cornell University)|Feb 11, 2026

Aerosol Filtration and Electrostatic Precipitation0 citations

TL;DR

The paper introduces triboFoam, an OpenFOAM-based solver for triboelectric charging in turbulent particle-laden flows, and shows Reynolds-number increases enhance wall-wall particle concentration and charging rates, with an empirical correlation provided.

ABSTRACT

Triboelectric charging in particle-laden flows is a complex interplay of fluid and particle dynamics, collision mechanics, and electrostatics. In this study, we introduce triboFoam, an open-source solver built on the OpenFOAM framework, designed to simulate triboelectric charging in particle-laden turbulent flows. We validate triboFoam using Direct Numerical Simulations (DNS) of a fully developed turbulent channel flow at a friction Reynolds number of $Re_τ= 180$. The results demonstrate good agreement with DNS data for particle concentration profiles and charge distributions. Then, we investigate the influence of Reynolds number on particle distribution and charging behaviour using Large-Eddy Simulations (LES) at varying friction Reynolds numbers up to $Re_τ= 550$. Our findings reveal that higher Reynolds numbers lead to increased near-wall particle concentrations and enhanced charging rates, attributed to intensified turbulent fluctuations and elevated impact velocities. Finally, an empirical correlation is proposed to predict the average particle charging rate as a function of Reynolds number and particle diameter. With this work, we provide a tool for simulating triboelectric charging in complex geometries and turbulent flows, advancing the understanding of electrostatic phenomena in particle-laden systems. The empirical correlation offers practical insights for predicting charging behaviour in industrial applications and thus can contribute to improved safety and efficiency in processes involving particulate matter.

Motivation & Objective

• Investigate how Reynolds number affects particle distribution and triboelectric charging in turbulent channel flow.
• Validate the triboFoam open-source solver against DNS and extend to higher Reynolds numbers with LES.
• Assess the influence of particle size on charging behavior under turbulent conditions.
• Develop an empirical correlation to predict average charging rate as a function of Reynolds number and particle diameter.

Proposed method

• Develop triboFoam on the OpenFOAM framework to simulate triboelectric charging in particle-laden turbulence.
• Validate DNS: fully developed turbulent channel flow at Re_tau = 180 with DNS data for uncharged and charged particles.
• Conduct LES up to Re_tau = 550 to study Reynolds-number effects on particle distribution and charging.
• Use an Eulerian-Lagrangian approach with WALE SGS model for LES and fully resolved viscous sublayer.
• Implement charging models (Condenser model and Stochastic Scaling Model) and a hybrid Gauss-Coulomb scheme for electrostatics.
• Consider 1-way, 2-way, and 4-way coupling between fluid and particles and include particle collisions via Hertzian theory and wall collisions.

Experimental results

Research questions

• RQ1 How does increasing friction Reynolds number Re_tau affect near-wall particle concentration and collision statistics?
• RQ2 How does Reynolds number influence the particle charging rate for different diameters?
• RQ3 What charging patterns emerge under the implemented models (Condenser vs. SSM) across Reynolds numbers?
• RQ4 Can an empirical correlation be established to predict average charging rate as a function of Re_tau and d_p?

Key findings

• TribooFoam validation against DNS shows good agreement for particle concentration profiles and charge distributions at Re_tau = 180.
• Increasing Reynolds number leads to higher near-wall particle concentrations and elevated charging rates due to stronger turbulent fluctuations and higher impact velocities.
• Higher Re_tau enhances wall-normal particle velocities and effective contact areas during collisions, contributing to increased charging.
• The study provides an empirical correlation to predict average particle charging rate as a function of Reynolds number and particle diameter.
• LES with fully resolved viscous sublayer up to Re_tau = 550 demonstrates Reynolds-number dependence of charging behavior beyond DNS-friendly regimes.
• Particle size influences Stokes number and hence coupling strength, modifying charging statistics across Reynolds numbers.