Characterization of flow field of swirling flow conveying in bulk grain pipeline based on gas‐solid multiphase coupling.

An experiment was carried out to study the characteristics of swirling pneumatic conveying of grain particles in horizontal pipeline, which can provide a reference for the design and optimization of swirling pneumatic conveying system of bulk grain pipeline. The numerical simulation of swirling pneumatic conveying under the guidance of vane swirling generator was performed via CFD‐DEM coupling method. The axial velocity of grain particles was symmetrical along the radial direction, and the tangential velocity was symmetrical along the pipe axis. When the blade number of the swirling device was 6–9, the static pressure drop and standard deviation of the flow field were large, the instantaneous energy consumption of the system and the dispersion of particles were high, and the conveying effect was good. When the blade number was six, the spiral distance of the flow field in the pipe was longer with better quality of swirl flow. In accordance with the simulation results, the best effect of swirling conveying is achieved when the equivalent diameter of the grain particles is 4 mm, the multiphase flow conveying speed is 20 m/s, and the spiral blade number of the swirling flow generator with flow deflector is six. Practical application: In the practical application, the swirling flow generated by the swirling device can suppress the settlement of particles and the blockage of the pipeline in the straight pipe conveying, and avoid the high speed collision between particles and the pipe wall in the curved pipe conveying, slow down the impact, reduce the particle breakage and the wear of the pipe wall. The generation and maintenance of swirling flow play a key role in the long‐distance conveying of various chemical raw materials, grain, fertilizer and other granular materials. Swirling flow pneumatic conveying has the advantages of simple equipment structure, small occupation space, flexible pipeline layout, easy to automatic control, high production efficiency, recycling, environmental protection, and so on. It has become an important conveying mode in bulk material conveying. [ABSTRACT FROM AUTHOR]