Collision characteristics of coal particles in arc-shaped plug elbow for pneumatic conveying

Abstract

Particle collisions are one of the main causes of elbow wear. In this study, an arc-shaped plug elbow was proposed. Combined with the pneumatic conveying experiment of coal particles and the computational fluid dynamics and discrete element method (CFD–DEM) simulation of Euler–Lagrangian bilateral coupling, the variation rules of particle distribution, elbow wear, particle velocity, and collision energy loss were analyzed, the weakening characteristics of the arc-shaped plug on particle collision and elbow wear were revealed, and the criterion of the optimal structure was deduced. The results show that the arc angle is the main factor influencing particle collision and elbow wear in arc-shaped plugs, which determines the reasonable range of the dimensionless height. The average particle velocity of the arc-shaped plug elbow decreased rapidly during the plug-filling stage and was much lower than that of an ordinary elbow during the stable conveying stage. The growth rate of the collision energy loss tends to stabilize after stable particle accumulation. This is an important criterion for the optimal structure, in which the arc angle satisfies the condition that the plug completely contains the radiation area of the wear center, and the dimensionless height satisfies the condition that stable particle accumulation is formed in the plug.