Design And Optimization Test Of Air Suction Floor Jujube Picking Machine

The annual output of Xinjiang jujube is about 3.4701×10~6 t,and the planting area reaches4.76253×10~5hm~2.The output and planting area account for about half of the country,especially in the southern Xinjiang region,which not only has a large planting area and has excellent natural conditions.In order to solve the problems of manual picking,such as high labor intensity,low efficiency and long operation cycle,which occurred during the harvesting of red dates,this paper designed a small air-sucking floor-standing red date picking machine,and verified its feasibility and working performance through field experiments.In order to further study the air-suction floor-standing jujube picker,this paper uses the CFD-DEM gas-solid coupling method and the Box-Behnken central combined test design theory to explore and analyze the pneumatic conveying motion characteristics and its details of the air-suction floor-standing jujube picking prototype.The main operating parameters and the structural parameters of key components affect its picking efficiency and breakage rate,and verify its feasibility and accuracy through experiments.The specific research contents are as follows:(1)By measuring the red jujube planting mode and its material characteristic parameters,it is summarized as three row spacing×plant spacing in different modes of the jujube garden,and the basic material parameters of the red jujube landed in the mature period are measured,mainly the triaxial size,single grain weight And density.The suspended velocities of grey jujube and junzao were 17.2~21.4m/s and 18.6~21.1m/s respectively,and the suspended velocities of jujube leaves and jujube branches were0.5~2.24m/s and 1.2~3.2 m/s respectively.(2)Combined with the jujube planting model and material characteristics parameters in southern Xinjiang,an air-suction floor-standing jujube picking machine was designed,and the whole machine structure,key components and operating principles were described and theoretically calculated.The field test results of the prototype show that the picking efficiency of the machine for junzao date garden is215kg/h,the impurity rate is 4.05%,the breakage rate is 3.65%,and the picking rate is 90.85%.The picking efficiency of the gray jujube planting date garden is 278kg/h,the impurity rate is 4.76%,the breakage rate is 4.24%,and the picking rate is 91.25%.(3)The CFD-DEM coupling method was used to simulate and analyze the red dates'pneumatic conveying process,and the particle position distribution and air flow field distribution of the red dates in the pneumatic conveying device were obtained.Through the simulation and optimization test of the original box,the optimized box can reduce the probability of the red dates passing through the barrier and prevent the occurrence of eddy currents,ensure that there is no residue of the red dates in the box,and the simulation results of the pneumatic conveying movement simulation It works.(4)The single-factor test results of the speed of the discharger show that when the speed of the discharger is 20r/min and the blade rotates counterclockwise,the damage rate of the discharger to the red dates is the lowest,and the damage rate is 0.12%.The test results of the fence selection show that the best effect is when the fence structure is inclined.(5)The box-Behnken central combination test method was used to determine the significance of factors influencing the picking efficiency and breakage rate.The suction efficiency,breakage rate and box inlet height,conveying pipe inner diameter,box outlet of the air-sucking floor jujube picking test prototype were constructed.Mathematical model of height,tip type and fan speed.The test results show that the factors that have a significant influence on the picking efficiency of the air-sucking floor jujube pick-up test prototype are:C>D>E>B;factors that have a significant effect on the damage rate The sequence is as follows:E>A>B;the optimal parameter combination obtained by analyzing the mathematical model is:box inlet height is 290mm,conveying pipe inner diameter is 130mm,box outlet height is 530mm,suction Head type is 2,fan speed is 2500r/min.At this time,the picking efficiency is 390.15kg/h,and the breakage rate is0.15%.In order to verify the accuracy of the mathematical model,the average values of actual pick-up efficiency and breakage rate measured by prototype tests were 372.33kg/h and 0.16%,and the relative errors with the optimized values were 4.57%and 6.25%,respectively.