Flow control study of pneumatic conveying bends using a wedge-shaped flow guide

In pneumatic conveying systems, bends are critical regions for energy loss, primarily due to particle-wall collisions and friction, which significantly affect conveying efficiency and system stability. This study proposes installing a wedge model inside bends as a bionic flow control structure. With the core mechanism of "minimizing friction distance," it aims to optimize particle trajectories, enhance gas-solid coupling, and reduce energy consumption. Based on established theoretical and experimental research on gas-solid two-phase flow, this work systematically analyzes particle motion characteristics and energy consumption mechanisms in two typical bends—horizontal-horizontal (H-H) and horizontal-vertical (H-V). It also investigates particle dynamics, gas flow, and pressure characteristics under the regulation of the wedge model. The results indicate that, through its gradually contoured profile, the wedge model guides the trajectory of particles after wall collisions within the mid-section of the bend (approximately at a bending angle of 45°–75°). This design facilitates particle detachment from the wall near the 75° bending angle and redirects them into the core flow region of the pipe. This significantly reduces particle-wall contact distance and frictional losses while enhancing the secondary acceleration effect of gas-solid drag on the particles. At the outlet region (90° bending angle), under the wedge-model condition, the average particle velocity increased by approximately 16.7% compared to the case without the wedge model. Particle radial distribution uniformity was notably improved, and particle-wall contact forces in the outlet section decreased significantly. Analysis of gas-phase velocity and pressure distribution revealed that the local throttling effect induced by the wedge model promotes airflow acceleration and turbulent diffusion, further optimizing gas-solid two-phase interaction. In summary, the wedge model serves as a composite energy-saving structure that integrates the functions of a collision buffer, an airflow accelerator, and a particle flow guide. It effectively reconstructs particle motion trajectories within bends, achieving minimized friction distance and efficient recovery of kinetic energy. This provides a novel technical pathway for the energy‑saving optimization and engineering application of pneumatic conveying systems.