CFD-DEM investigation and analysis of non-spherical particles tribocharging in a horizontal-bend-vertical pipe

• Superquadric particle tribocharging is simulated in a horizontal-bend-vertical pipe. • Higher charge in non-spherical particles arises from enhanced P-P/W contacts. • Charge and drag force distributions and contact information are analyzed. • Effective discharge points are identified for different particle shapes and phases. • Wall erosion is intensified with superquadric particles at deeper bend locations. Triboelectric charging, resulting from repeated particle-particle (P-P) and particle-wall (P-W) interactions, critically affects process safety and efficiency, yet remains insufficiently understood. This study presents a numerical investigation of tribocharging in a horizontal-bend-vertical pipe using our recent combined Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model, which is capable of modeling impact and frictional charging for various particle shapes. Dense- and dilute-phase conveying of non-spherical particles is simulated to assess charge evolution, wall erosion, gas-solid flow behavior, and P-P/W contact information. Charge mitigation strategy is explored, and pipe erosion under various particle shapes is also evaluated. Results reveal strong shape-dependent charging characteristics. Prolate particles achieve the highest equilibrium charge due to their elongated shape, which enhances P-P charge transfer, while oblate particles charge rapidly via extensive wall contact. Charge accumulation is amplified at bends, where secondary flows increase collision frequency and intensity. Shape-dependent drag forces and flow patterns show that particle layering and suspension govern triboelectric behaviors. Numerical results further show that strategically placing discharge points upstream of bends in the dense phase and downstream of bends in the dilute phase can substantially mitigate charge buildup. Additionally, pipe erosion intensifies with the presence of non-spherical particles. Maximum erosion occurs in deeper bend areas with non-spherical particles in the dense phase, while erosion distributions become similar in the dilute phase. A single charging cycle has a negligible impact on tribocharging-induced pipe erosion. This study offers insights into complex bend phenomena that can facilitate industrial applications.