关键词: 颗粒模型, 接触参数, 标定, 离散元, 稻谷

Abstract: The credibility of simulation results was directly affected by the accuracy of rice grain parameter setting when EDEM coupling with FLUENT to simulate rice separation. In this paper, combined the measured and simulation test of rice grain response angle, two main contact parameters between rice grain models, static friction coefficient and rolling friction coefficient, were calibrated based on discrete elements. A response angle measuring device was designed to form two kinds of response angles  using collapse and injection, which could reduce the measurement error caused by non-simultaneous formation,  create a discrete element model of rice grain, combine the actual test and simulation test of the stacking angle, and establish the binary equation regression between two main contact parameters and two response angles. The measured results of the two kinds of response angles of rice grains were used as the correction index to solve the equations, and obtained the static friction coefficient and the rolling friction coefficient of the rice grain model were 0.433 6 and 0.161 5, respectively. The throwing test was designed to verify the calibrated parameters. The length and width of the throwing, and a response angle neared the spray point in experiment were compared with them in simulation, and the result showed that the relative error was less than 5.7%. These results indicated that the simulated motion trajectory of the particles was basically consistent with the actual trajectory. The discrete element model of the rice particles and the contact parameters obtained by the calibration can provide reference for the EDEM-FLUENT simulation of the rice cleaning process.

Key words: granular model, contact parameters, calibration, discrete element method, rice