Numerical analysis and improvement method of screening effect during radial segregation of rice in the indented cylinder separator

Abstract

Screening of broken rice is the key to improve rice quality and economic benefits. Unfortunately, the screening effect of broken rice in separators is always adversely affected by radial segregation, seriously affecting production efficiency. However, the mechanism by which segregation influences the screening effect of broken rice remains unclear. Additionally, the lack of an effective improvement method restricts the development of the rice processing industry. In this study, the screening process of broken rice within an indented cylinder separator was numerically analysed based on discrete element method. The results showed that enhancement of the separation ability of particle system will indeed lead to the deterioration of the screening effect. A strong correlation exists between the quantity of rice entering the indentation and the radial concentration of rice. Greater radial broken rice concentration (C_rb) in outer layer means better screening effect. In segregation process, the C_rb gradually decreases in outer layer and increases in core layer. Besides, study found that radial distribution of rice is caused by joint action of radial segregation and disturbance zone. Besides, broken rice gradually moves and gather towards the core layer under the segregation influence. Finally, based on the principle of reducing segregation ability of the particle system and expanding the influence of disturbance zone, a new type of strip baffle is proposed first. Compared with original equipment, the screening effect can be improved by 57.24 % significantly. The research results can provide assistance for the research and optimisation of indented cylinder separators or similar separation equipment.