Simulation of Non-Spherical Rice Seed Motion in Pneumatic Conveying with Bend by CFD-DEM

The rice flow characteristics in pneumatic conveying determined the performance of pneumatic metering device for rice seed. The non-spherical rice seed motion in pneumatic conveying with bend was investigated by CFD-DEM simulation. The rice seed particle model was established by multi-sphere method, and a typical pneumatic conveying horizontal-vertical pipe with bend was selected. The applicability of three drag force models on non-spherical particle was compared. The particle flow characteristics in different pipes including the vertical-horizontal pipe and the horizontal-horizontal pipe were investigated. The non-spherical particle formed a particle rope at the outlet of bend, and the particle rope dispersed at downstream of the vertical pipe. The effect of particle shape on gas-solid flow characteristics was obtained. The gas velocity value in the bend for non-spherical rice particle was higher than that for spherical particle. The non-spherical rice particle rope dispersed more slowly than the spherical particle rope. The particle velocity profile of non-spherical and spherical particles was similar. The differences of the gas-solid flow predicted by Free stream model, Ergun and Wen & Yu model, and De Filice model were limited. The particle rope can also be formed in vertical-horizontal pipe and horizontal-horizontal pipe, but its dispersion represented different features. The results showed that particle shape and structure of pipe can influence the gas-solid flow characteristics, and a suitable particle model was important for the gas-solid flow simulation by CFD-DEM.