Calibration of discrete element simulation parameters of Chinese medicine extract powders / 中草药

ABSTRACT

Objective: The discrete element method (DEM) was used to simulate the angle of repose of Chinese medicine extract powders. The contact parameters between particles and between particles and geometry were calibrated. Methods: The licorice extract powder, the extract powders of Angelicae Pubescentis Radix (Duhuo), microcrystalline cellulose (MCC) and ethyl cellulose (EC) were taken as the research objects. DEM was performed based on the Hertz-Mindlin with JKR Cohesion contact model and particle scaling. The Plackett-Burman design was used to screen out the critical contact parameters that had significant impact on the simulation measurement of the angle of repose. Then, the steepest climbing design was used to determine the best area of critical contact parameters. After that, a regression model between the contact parameters and the simulated angle of repose was established according to the Box-Behnken test results, and the best contact parameter values were optimized and verified. Results: The critical contact parameters selected were particle-particle rolling friction coefficient, particle-particle restitution coefficient and particle-stainless steel restitution coefficient. The calibration range of the built regression model was from 33.30° to 43.64°. The absolute values of the relative error between the simulated values and the experimental values of the angle of repose for four powders were all less than 2.0%, indicating that the established calibration method was accurate and reliable. Conclusion: This article proved the feasibility of calibrating the DEM micromechanical parameters of the Chinese medicine particle system through the macroscopic physical parameter, and laid the foundation for accurate simulation of Chinese medicine pharmaceutical processes like powder mixing and conveying.