Abstract

Accurate discrete element simulation parameters for the mechanically harvested cotton stalks and cotton residues mixture are currently unavailable. This lack hinders the effective design and optimization of equipment for separating and recovering cotton residues from the mixture. This study focused on the cotton stalks and cotton residues mixture. The intrinsic parameters of cotton residues were measured through physical experiments. Using the inclined plane and collision methods, the coefficients of restitution for cotton residues–cotton stalks and cotton residues–steel were determined to be 0.228 and 0.364, respectively. The corresponding static friction coefficients were 0.632 and 0.266, and the rolling friction coefficients were 0.199 and 0.156. The Hertz–Mindlin with JKR contact model was employed. Combined with repose angle tests, the coefficient of restitution, rolling friction coefficient, static friction coefficient, and surface energy for cotton residues–cotton residues were calibrated as 0.393, 0.140, 0.742, and 1.471 J/m2, respectively. A vibrating spreading test was conducted to validate the calibrated parameters. The proportion of cotton residues on the material surface was used as the test index. The mean relative error between simulation and physical test results under four working conditions was 4.91%. The results indicate that acceptable consistency is achieved between simulation and experimental results under the tested conditions, and the calibrated discrete element parameters are applicable for the simulation of cotton stalk–cotton residue mixture systems. This study provides a theoretical basis and data support for the development of equipment to separate and recover cotton residues from cotton stalk and cotton residue mixtures.

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