Numerical study on the fine particle deposition in a squared duct bend during high-speed pneumatic conveying using the Thornton and Ning elastic-perfectly plastic adhesive particle contact model

Fine particles are found to easily deposit on the wall of bends during high-speed pneumatic conveying, under which the plastic deformation is non-negligible due to critical particle–wall collisions. Therefore, this study aims to investigate the effect of plastic deformation on fine particle deposition. The Thornton and Ning (TN) elastic-perfectly plastic adhesive particle contact model, which considers the plastic deformation into particle deposition, is utilized to numerically investigate 50µm fine particle deposition in a squared duct bend (cultivation ratio equals 1.76) from Kliafas’ experiment under high bulk velocity 52.19ms⁻¹ and 33.09ms⁻¹. The yield stress of particles 0.25–2.0GPa is selected to represent the intensities of plastic deformation. Furthermore, the relationships between particle deposition and plastic deformation under various bulk velocities (5–55ms⁻¹) and particle diameters (5–50µm) are discussed, respectively. The results show that the simulation achieves over 90% consistency in predicting particle velocities, over 70% in predicting particle turbulence intensities, and only 0.44% error (lowest compared to collision models from previous studies) in predicting particle free region length with Kliafas’ experiment. The simulated deposition positions show 90% of particles deposited after the bend and accumulation of deposited particles in the corner, which agrees with previous experimental studies. Results also demonstrate that higher plastic deformation critically increases deposition but shows no effect under low flow velocity (≤5ms⁻¹) or small particle diameter (≤5µm) for the glass system. This work will benefit the understanding and application of fine particle pneumatic conveying under high conveying speed.