Numerical simulation of flow characteristics for non-spherical particle mixture flowing in moving bed

Abstract

Environmental pollution problems are more serious with the rapid economic development. The study of particle flow characteristics is a hot issue for scholars. In many ways to tackle air pollution and solid waste, the particle flow characteristics can play a decisive role. Then in the actual process, the non-spherical particle such as active carbon and solid waste were always treated as spherical particles during the simulation. It could cause large errors. This study was mainly to simulate the non-spherical particles. Three kinds of non-spherical particles including corn-shaped particle, cylinder paritcle and ellipsoidal particle were developed by multi-element particle model. The motion equation for non-spherical particle mixture was founded based the analysis on the collision mechanism and the typical collision mode. The flowing condition of non-spherical particle mixture in moving bed was simulated through experiment, which verified the the reliability of multi-element particle model. The discharge rate, flow pattern, particle density distribution and voidage variation for non-spherical particle mixture were discussed further. The results showed that the discharge rate for non-spherical particle mixture was fundamentally the same as single non-spherical particle. However, the value for spherical particle was larger than that of spherical and non-spherical particle mixture. The MFI values (the particle speed ratio of bedside to centre in moving bed) of nonspherical particles mixture were closer to the corresponding homogeneous particles. The particle density distribution of spherical and spherical-nonspherical mixture generally had one peak, while that of non-spherical particle and non-spherical particle mixture always had two peaks. The wall effect and the average voidage of three kinds of non-sphercial particle mixture were almost the same. The average voidage of three kinds of non-sphercial particle mixture are almost the same.