Parameter Optimization and Analysis of Quinoa Dehulling Process Based on Discrete Element Method

This study addresses the challenges of low dehulling efficiency, high broken grain rate, and poor process visibility in current quinoa dehulling equipment by proposing an optimization strategy combining the discrete element method and response surface methodology. Initially, a kinetic motion model of quinoa grains within the milling chamber was established. Simulation analysis of grain movement behavior under different structural parameters was conducted using the EDEM software, revealing grain velocity distribution, contact force characteristics, and the primary milling zones. Subsequently, single-factor experiments combined with a Box-Behnken response surface methodology were conducted to systematically evaluate the effects of three key operational parameters-rotational speed, dehulling gap, and inlet opening-on the dehulling rate and the broken grain rate.Quadratic regression models were developed and subjected to analysis of variance. The results indicate that the inlet opening has the most significant impact on the dehulling rate, while the dehulling gap is the dominant factor affecting the broken grain rate. Multi-objective optimization yielded the optimal parameter combination: rotational speed of 1229 rpm, dehulling gap of 4.51 mm, and inlet opening of 84.47%. Under these conditions, the predicted dehulling rate was 78.98% with a broken grain rate of 7.82%. Validation experiments were performed using a purpose-built physical test platform. The measured dehulling rate reached 81.23% with a broken grain rate of 7.81%. Deviations between the experimental results and simulation predictions remained within acceptable margins, confirming the accuracy and practicality of the developed model. This research provides valuable insights for enhancing the operational quality of low-cost quinoa dehulling equipment.