Research On The Key Dust Proof Technology Of Air Suction Seeding System Of No-tillage And Straw Mulching Precision Planter In Original Stubble Field

This study was conducted with the support of the Special Fund for the Construction of Soybean Industry Technology System(No.CARS-04)and the National Key Research and Development Program(No.2021YFD2000401).When the air suction seeding system works with no-tillage planter,it has some problems,such as difficult seed suction,low seed quality and low reliability due to dust inhalation.In order to solve the above problems,based on the no-tillage and straw mulching precision planter in original stubble field,this study proposed a dust proof technique for air suction seeding system,and designed a dust proof air suction seeding system.The system can effectively prevent dust from affecting the air suction seeding process.By means of theoretical analysis,computer simulation analysis and field test,the distribution law of dust in operation was confirmed,the key components of dust proof air suction seeding system were developed,and field verification test was carried out.The main research contents and conclusions are as follows:(1)Determination of dust composition and related physical property parameters.The dust of no-tillage and straw mulching precision planter in the original stubble field was collected and measured,and the dust composition,content,moisture content,shape and size,friction factor,collision recovery factor,Poisson’s ratio and shear modulus were obtained.(2)Study on dust distribution law of high-speed operation of no-tillage and straw mulching planter in the original stubble field.Taking the no-tillage and straw mulching planter in the original stubble field as the research object,the dust movement kinematic model was established through theoretical analysis,and the key factors affecting the dust distribution were clarified.Based on the measurement results of dust physical parameters,the CFD-DEM coupling numerical simulation model was established,and the quadratic regression orthogonal rotating center combination test method was applied.With taking operation speed,wind direction angle and wind speed as test factors and dust concentration as evaluation index,the operation speed was selected as 7.2-10.8 km/h,wind direction angle was selected as 0°-213.75°and wind speed was selected as1-11.1 m/s according to the statistical results of natural wind during corn seeding period in the black soil area of northeast China.The virtual simulation test was carried out,and test results show that each factor has a significant influence on dust concentration,and the order of influence is wind speed,wind direction angle and operation speed.Dust mainly distributes in the left and right side of the no-tillage planter and around the seeding monomer,and the secondary distribution in the front of the no-tillage planter,above the seeding monomer and above the seed bed preparation device.The minimum dust concentration distribution space is the upper area of the seed bed preparation device.The verification test results show that the similarity is greater than 91.4%,which proves that the simulation results are reliable.(3)Design of dust proof technical scheme and matching device for air suction seeding system of no-tillage and straw mulching precision planter in original stubble field.Based on the structural characteristics and working principle of no-tillage and straw mulching precision planter in original stubble field,a dust proof technical scheme of air suction seeding system was put forward,and a dust proof air suction seeding system was designed.The design principle,overall structure and working principle were expounded,and the key structure and components of the system were designed.The air inlet of the air suction type exhaust device was improved to be a cylindrical air inlet with an outer diameter of 50 mm and an inner diameter of 48 mm,and the selection of the negative pressure fan was completed.The installation position of the designed filter was the upper area of the seed bed preparation device.The model of the selected filter was centrifugal with oil bath filter.The design size of the intake pipe was 52 mm in diameter and 1500 mm in length.(4)Prototype trial production and field test.The manufacturing of the test prototype of the dust proof air suction seeding system test device was completed.The field test was carried out with three factors and five levels quadratic regression orthogonal rotating center combination test method.The operating speed,rotating speed of straw cleaning knife and straw mulching amount were taken as test factors,dust proof efficiency and grain spacing qualified index were taken as evaluation indexes.The test results showed that the primary order of influence of each factor on dust proof efficiency was straw mulch amount,rotating speed of straw cleaning knife and operating speed,and the primary order of influence on grain distance qualified index was operating speed,rotating speed of straw cleaning knife and straw mulch amount.When the optimal parameter combination was as follows:working speed 7.2-8.55 km/h,rotating speed of straw cleaning knife 400-476.22 r/min,straw mulching amount 1.96 kg/m~2,dust proof efficiency was greater than 94%,grain spacing qualified index was greater than 80%.The validation test was carried out with the above parameter combination,and the results showed that,the relative error was less than 3.80%,which proved that the optimized test results were reliable and met the national standards and design principles.The influence law of operation time on working performance of the optimized dust proof air suction seeding system was studied.The single factor test was carried out with operation time as a single factor variable and dust proof efficiency and intake negative pressure as evaluation indexes.The test results showed that:operating time has a very significant effect on dust proof efficiency and intake negative pressure,in which the dust proof efficiency and operation time show a natural logarithmic function relationship,and the intake negative pressure and operation time show a linear function relationship.When the operation time is more than 35.2 h,the dust will wear more on the internal parts of the air suction seeding system,so it is recommended to clean the accumulated dust.When the operation time exceeds 193.9 h,the negative air intake pressure cannot meet the normal seeding needs,it is necessary to clean up dust accumulation.