Research on the Cluster Hole Effect and Performance Testing of Air-Suction Quinoa Seed Metering Device

Quinoa and other small-seeded crops possess relatively diminutive seed diameters, rendering them highly susceptible to the influence of airflow. The seeding process is impacted by the Cluster Hole Effect, where seeds are unintentionally drawn into areas between the suction holes. This leads to multiple seeds being picked up at once, making it difficult to meet the precise seeding requirements for quinoa. To delve deeper into the mechanism of the cluster hole effects, this study focused on quinoa seeds as the primary research subject. This study analyzes the migration conditions of seed population suction and establishes an equation for seed suction considering the cluster hole effect. CFD methods were employed to analyze the impact of various vacuum chamber negative pressures, suction hole spacing, and suction hole quantities on the suction flow field. By combining simulation results with evaluation criteria such as the qualification rate of seeds per hole, the qualification rate of hole spacing, empty hole rate, and hole spacing coefficient of variation, single-factor experiments and Box-Behnken response surface experiments were conducted to analyze the effects of different factors and their interactions, ultimately determining an optimal parameter combination. The results indicate that with five suction holes, spaced at D11, a vacuum pressure of 1.2 kPa, and a rotation speed of 15 rpm, the seeding performance is optimal. The qualification rate of seeds per hole reaches 98.67%, the qualification rate of hole spacing is 96%, and the hole spacing coefficient of variation is 5.24%, meeting agricultural requirements.