Design And Experiment Of Pneumatic Disc Seed-metering Device For Mini-tuber

Potato is the world’s fourth largest grain crop after maize,wheat and rice.Under the harsh environment of social degradation and arable land,the development of potato industry is an effective way to ensure the total grain output in China.China has become the world’s largest potato production,but it is not a potato industry power,one of the reasons is that China’s potato industry is mainly to cut potatoes for the seed potato,easy to produce virus infection;Second.China’s low level of mechanization of potato production With the breakthrough of potato potato seed virus technology research in China,the production of high quality detoxification micro potato has gradually entered the commercialization stage,which means that the problem of poor quality of potato in China’s potato industry has been solved.Most of the existing potato planting equipment at home and abroad to cut the kind of potato or whole potato as the object of operation.In order to realize the mechanized planting of mini-tuber and solve the problem of large seed filling,a vibrating feeding pneumatic disc seed-metering device for mini-tuber was designed.The seed-metering device was made up of metering plate,air chamber,frame and vibrating seed feeding device.The working principle of the pneumatic disc seed-metering device was expounded.The physical properties of mini-tuber which included of geometric dimension,average weight and angle of repose were researched.The structural parameters of metering plate were determined by the theoretical calculation,which contained the metering plate diameter,suction hole diameter and suction hole number.The FLUENT software was used to analyze the internal flow field of air chamber and optimize the location of pressure-outlet.The vibration frequency was calculated and verified by analyzing the movement characteristics of vibration plate.Concrete study content as follows:(1)The physical and mechanical properties of micro-potato were studied.Included the three-axis size,moisture content,average grain weight,density,and the static and dynamic friction angle with different materials.(2)a vibrating feeding pneumatic disc seed-metering device for mini-tuber was designed.The seed-metering device was made up of metering plate,air chamber,frame and vibrating seed feeding device.The working principle of the pneumatic disc seed-metering device was expounded.The physical properties of mini-tuber which included of geometric dimension,average weight and angle of repose were researched.The structural parameters of metering plate were determined by the theoretical calculation,which contained the metering plate diameter,suction hole diameter and suction hole number.(3)The FLUENT software was used to analyze the internal flow field of air chamber and optimize the location of pressure-outlet.The vibration frequency was calculated and verified by analyzing the movement characteristics of vibration plate.In order to verify the performance of the seed-metering device and find the best parameter combination,the orthogonal test were carried out with the eligible index,multiple index,missing index as experimental index and the operating speed as experimental factors.The optimal experimental results were:the operating speed of 2.4km/h,vibration frequency of 6.5Hz,negative pressure of 6kPa,and the corresponding performance indexes are as following:the eligible index is 94.2,the missing index is 1.7 and the multiple index is 4.1,which could completely meet the requirement of the technical specifications of quality evaluation in China.(4)In order to improve the seed-filling performance of he pneumatic disc seed-metering device,Lishu No.6 mini-tuber were adopted as sowing object,the method of EDEM was used as research technique,meanwhile,variance yields of average normal stress was considered as the optimizing targets.Through single factor experiment,the vibration frequency and vibration amplitude were numerically simulated respectively.It can be found that the experimental phenomenon and effect were in consistent with the simulation ones.Results showed that vibration frequency and vibration amplitude increase variance yields of average normal stress of seeds,hence disturbance of seeds was enhanced.Based on the three-factor five-level quadratic orthogonal rotating combination test method,the influence of Vibration frequency,Vibration amplitude and layer height on sowing performance were explored.The regression equations of the 3 factors and 5 levels were fitted through the processing by Design Expert 8.0.6(experimental design expert)software.Based on the results of examination,it can be found that the fitting of the equation was good,the best parameter combination was vibration frequency of 6.5～7.0 Hz,vibration amplitude of 20～21 mm and layer height of 70 mm,under the optimal condition,the qualified index was greater than 95,the multiple index and the missing index were less than 2.5.(5)Researched the damage of mini-tuber caused by the machine,the breakage rate were under 1%with different vibration frequency.This study can provide references for further improving quality,optimizing the parameter for pneumatic disc Seed-metering device and designing the potato planter used in farmland.