ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

Considering the practical problem that the poor mobility and low sphericity of sesame seeds make it difficult to fill seeds during seeding process and to achieve precision seeding, based on the mechanical and physical properties and parameters and the demand of planting agronomy for sesame, a precision metering device for sesame seeds was designed, which used slotted-tooth spoon holes to fill seeds and air delivery to assist seed feeding. The key structural parameters of seed metering device were determined, and the mechanical model of seed particle group during seed filling, seed carrying and seed supplying was established. The performance of seed metering device was simulated and optimized by using discrete element software EDEM. The influence of the hole depth, the angle of right wall of the shaped hole and the angle of slotted-tooth spoon hole on variation coefficient of seeding amount uniformity in each row and average sowing amount per minute were studied by Box-Behnken response surface optimization method and three-factor and three-level orthogonal simulation experiment. The variation coefficient of seeding amount uniformity in each row and average sowing amount per minute were 1.69% and 3.7g/min, respectively, when the hole depth was 1.92mm, the angle of the right wall of the shaped hole was 8.4°, and the angle of slotted-tooth spoon was 28.6°. A two-factor and three-level bench test of seed metering device performance was carried out. The test factors were the rotation speed of seed metering shaft and the filling height of the seed layer. The variation coefficient of total seeding stability and the variation coefficient of seeding amount uniformity in each row were taken as the test evaluations. The results showed that seed metering device had the best performance when the rotation speed of seed metering shaft was 15r/min and the filling height of the seed layer was 10mm. And variation coefficient of total seeding stability, the variation coefficient of seeding amount uniformity in each row were 1.62% and 0.40%, respectively, which met the agronomic requirements of sesame planting. The field experiment demonstrated that the uniformity coefficient of variation of the number of seedlings in each row was lower than 4% and the average planting density was 36 plants/m2, when the forward speed of seed metering device was 2.9km/h. The research result can provide a reference to improve the structure of metering device for sesame seeds.