Optimization and Experiment of Pneumatic Seed Metering Device with Guided Assistant Filling Based on EDEM-CFD

According to the declining seed quality of the air suction seed metering device guided with assistant seed-filling caused by high speed operation in the field, the design of the seed metering device was optimized. The structure parameters of seed plate to be optimized was defined by analyzing the factors of obstructions during seed filling process. According to the determinacy tracking model of the grain model, the gas-solid two-phase flow of the seed metering device was calculated by introducing the pressure gradient force model into coupled analysis of EDEM-CFD. Critical points of seed filling process in each stage was divided on the scales of macro and micro. The most suitable factors of seed filling state during each state were analyzed. Three factors quadratic rotation orthogonal combination tests were carried out with the index of the stable time during seed adsorption, the resistance during seed removing stage and the local void ratio at the hole, with the test factors of the Curvature coefficient of seed guide groove curve of seed plate, the depth of seed guide groove, the slope angle of seed guide groove. The optimal parameter combination of seed guide groove of seed metering plate was determined by multiple regression analysis of test results and multi-objective optimization method. The results were given as follows: the curvature coefficient of seed guide groove curve was 0.265, the depth of the seed guide groove was 2.57 mm, and the slope angle of seed guide groove was 15.33°. In order to verify the results of optimal design, the static tests were carried out on the bench of seed metering device, the indoor vibration environment simulation tests of the seed meter device were carried out according to the vibration signal of the seed meter collected from operating in the field. By comparing the optimized seed plate with original seed plate and the other two testing plates, the result showed that the optimized seed plate had a better performance at high speed and vibration conditions. The seed filling performance was more stable, and the miss rate was 1.26% when the operating speed was 14 km/h, the main excitation frequency of random vibration was 9.5 Hz, and the peak value of power spectral density was 0.428 (m/s2)2/Hz. © 2020, Chinese Society of Agricultural Machinery. All right reserved.