Development of a model for triboelectric charging during particle-particle collisions

• Applicant: Dr.-Ing. Holger Grosshans
• Subject Area: Fluid Mechanics ; Mechanical Process Engineering
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 562343622

Electrostatic charging significantly impacts industrial powder processes, contributing to wall fouling, explosions, and other operational challenges. However, no validated model exists for the electrostatic charging of particles that can be implemented in CFD simulations. Many experiments and projects try to derive models for particle-wall charging. But controlled experiments on charge exchange during particle-particle collisions, where both contacting objects fly with high velocities, are much more difficult to design. Consequently, no reliable model for particle-particle charging is available. This proposed project aims to leverage the technologies, models, and unique expertise for particle-wall charging developed under our ERC project to address particle-particle charging. The first step involves designing a novel particle-particle charging apparatus. By employing acoustic levitation to hold one of the two particles in a fixed position, we aim to achieve a higher collision success rate than earlier methodologies. Next, the experimental data obtained from this apparatus will inform the development of a particle-particle charging model, which we will integrate into our open-source CFD code, pafiX. Finally, we will validate the simulations using our pneumatic powder conveying test rig, equipped with advanced measurement technology capable of spatially resolving electrostatic charges—a significant improvement over conventional integral charge measurements. Doing so ensures a high level of validation of the CFD simulations. This project will collaborate with experts in the field, including Professor Poupak Mehrani (University of Ottawa), a pioneer in particle-particle charging experiments. Also, we incorporate Professor Alberto Passalacqua (Iowa State University, US) as Mercator Fellow, who heads one of the leading groups in CFD modeling of fluidized beds. Together, these partnerships will enhance the impact and applicability of the project’s outcomes. By addressing a critical gap in the numerical modeling of particle-laden flows, the proposed particle-particle charging model aims to improve the safety and sustainability of industrial processes.

• DFG Programme: Research Grants
• International Connection: Canada, USA
• Cooperation Partners: Professorin Dr. Poupak Mehrani; Professor Dr. Alberto Passalacqua