Dynamic model for sucking process of pneumatic cutting-type safflower harvest device

Abstract: This study proposed a method using negative pressure sucking the petals adhered around cones. The structural parameters of the sucking device affect the flow-field distribution in the negative-pressure air chamber. In order to improve the harvesting efficiency and quality of the pneumatic cutting-type safflower harvest device, a dynamic model was established and the safflower petals upwind area were measured. According to the test, the size parameters of the thornless Yumin safflower were as follows: the average necking diameter was 6.30 mm, the average capitulum diameter was 20.89 mm and the average petal length was 22.39 mm. The measured maximum frontal area of the safflower petal was 11-40 mm2. Secondly, the required negative pressure power that resulted in the rise of safflower petals was calculated. In general, when the suction of the negative pressure reaches 9.8 m/s, the safflower petals can be sucked successfully. The simulation of the flow field in the suction mouth indicated that the streamlined suction mouth was beneficial in reducing resistance and the test results of high-speed photography showed that the aforementioned condition could improve the efficiency of the upright safflower. And the test verified that the rate of the unshaped petals in the cylindrical air tunnel was low and the efficiency of carding and shaping under negative pressure was considerably better in wet petals than in dry ones. Results of the upright safflower petal experiment were consistent with the theoretical analysis and simulation conclusion, and indicated the precision of the dynamic model and suction flower mouth orifice-shaped simulation analysis.