Particle Movement Mechanism of Wheat Particles in a 90° Bend of a Pneumatic Conveying System

To investigate the motion mechanism and kinetic energy loss characteristics of wheat particles in a horizontal–vertical upward bend pipe, different curvature radii, gas velocities, and particle mass flow rates are used to study changes in particle velocity, the inter-particle contact force, and the particle–wall contact force in this study. The results indicate that larger curvature radii weaken the inter-particle contact force. The velocity difference between particles inside and outside of the bend first increases and then decreases at the elbow. Increasing the gas velocity increases the particle velocity and the particle–wall contact force. It also enlarges the velocity gap between the inner and outer particles of the bend, while weakening the inter-particle contact force. With an increase in the mass flow rate, the particle–wall contact force gradually rises at 0–30° of the bend, and then gradually falls at 30–90°. Meanwhile, the inter-particle contact force is enhanced. A higher gas velocity leads to a greater loss of particle kinetic energy caused by collisions. The velocity difference exhibited by particles on the inner and outer sides of the bend remains basically unchanged. The maximum inter-particle and particle–wall contact force is around the 30° bend angle.