Simulation analysis and match experiment on negative and positive pressures of pneumatic precision metering device for rapeseed

Positive and negative pressures determine the performance of pneumatic precision metering device for rapeseed.In order to investigate the relationship between positive and negative pressures of nozzles,fluid models of chamber were developed to simulate the airflow,and the k-εturbulence model was conducted to capture the pressure and velocity of nozzles.Through these efforts linear models were achieved.Meanwhile,the three-factor factorial split-split experiment was designed with negative pressure,positive pressure and the rotating speeds varying from-1000 to-4500 Pa,50 to 250 Pa and 10 to 45 r/min,respectively.The mathematical models were developed through employing the stepwise regression method.The sequence of influential factors on the quality of feed index was positive pressure,negative pressure and rotating speed.To obtain the match regulation of negative and positive pressures with“good”performance,the ratio coefficient K of negative and positive pressures was introduced to build mathematical models.Models relating ratio coefficient K with positive pressure were fitted in different rotating speeds.The results showed that the ratio coefficient was matchedГ∈[f1(x),f2(x)]from the fitting equations with the rotating speed of 10-30 r/min;while the rotating speed has greater influence when it was 35-40 r/min and the setsΛ∈[g1(x),g2(x)]were achieved,where x∈[100,250].This study could be conducted to adjust the rotating speed of the pneumatic system to optimize the ideal performance of the seeder.

Vacuum and Air Flow for 2QXP-1 Vacuum Precision Seed Metering

Vacuum precision seed metering is the key part of vacuum seed planter. Planting performance of planter is affected by vacuum and air flow which are important parameters for choosing fan. Effects of qualification percent and miss percent on air chamber vacuum 3, 4, 5 and 6 kPa were studied at different operating speeds. The results showed that operating performance of the seed metering was excellent when air chamber vacuum was 5 and 6 kPa, which air flow was 7.4-8.0 m3·s-1 and 8.0-8.8 m3·s-1 , respectively.

Design and experiment of the pneumatic double disc precision seed metering device for Chinese flowering cabbage

Single seed metering devices for Chinese flowering cabbage planting machines have suffered such deficiencies as low efficiency,poor accuracy,and instability.To overcome these limitations,a pneumatic double disc precision seed metering device was designed.This innovative device can simultaneously plant four rows,considering the specific agricultural requirements and the geometric characteristics for Chinese flowering cabbage seeds.The precise parameters of the key component seed disc were derived through theoretical calculation.In addition,a detailed account was given for the working principle and workflow of the seed metering device.The discrete element method and EDEM software were employed to optimize the seed disc by exploring the effects of seed disc rotational speed and interleaving seed slots on seed viability.Orthogonal rotation experiments were conducted to evaluate the impact of seed disc rotational speed and negative pressure.While rates of qualified seeding,double seeding and missing seeding were adopted as test indicators.Testing results show that,at a seed disc rotational speed of 41.5 r/min and a negative pressure of 3.80 kPa,the average qualified seeding rate is 90.13%,the average missing seeding rate is 3.30%,and the average double seeding rate is 6.02%.These values satisfy the agricultural requirements for planting Chinese flowering cabbage.The findings can also provide valuable insights for the structural optimization and design of precision seed metering devices for Chinese flowering cabbage.