| Potato is a food crop that is suitable for both North and South.It has many varieties,high nutritional value,and strong environmental adaptability,which is grown all over the country.Therefore,aiming at the characteristics of minitubers with large differences and easy damage during seeding,design an air-suction vertical circle suitable for minituber seeding.At the same time,it also has good adaptability to potato minitubers with large individual differences in shape,which can effectively reduce replays or missed caused by individual differences in shapes and improve the level of mechanization.The main research contents are as follows:(1)Determination of physical and mechanical properties of potato minitubers."Daxiyang","Zhongshu No.5" and "Huashu No.1" were taken as research objects.The relevant parameters required for the minituber research are taken as targets to determine the physical and mechanical characteristics of the minituber.inclouding triaxial size,mass,Radius of curvature,density,Poisson’s ratio and shear modulus.The contact mechanical parameters of three kinds of minitubers and three kinds of materials(between steel plate,ABS and minitubers of different varieties)were measured.(2)Design of air-suction potato minituber seeding device.Using the principles of suction under negative pressure and the principle of gravity seeding,using CREO design an air-suction seed meter for single-grain of minitubers.The structure and principle of the seed metering device were expounded,and the key components of the seed metering device were designed and analyzed.(3)Research on seeding mechanism of minituber based on dimensional analysis.The method of quantity dimension analysis was used to analyze the suction process of the aspirated minituber metering device.Taking the qualified index,missed seed index and replay index as the seeding quality indicators,and through the relationship between the structural parameters,operating parameters and experimental results of the metering device constructing the mathematical model of the correlation between the parameters and performance.Take the suction hole diameter,air mass density and suction hole linear velocity as the repeating dimension,write the dimensionless parameter relational expression related to the repeating variable and write its dimensional harmonious equation group to get the dimensionless relational expression.From the derivation formula,we can see that the seeding index of the seeding device is related to the size and number of the holes,speed,vacuum,Reynolds number and Euler number.(4)Experimental research on air-suction miniature potato seeding device.Taking the vacuum degree of the gas chamber,the rotation speed of the seeding shaft,the diameter and number of the hole as the influencing factors,combined with the bench test data,the single factor and quadratic regression orthogonal rotation test were used to analyze the influence of variable variables on the seeding quality index.The influence of the diameter of the hole and the number of holes on the seeding performance is reduced in turn.When the vacuum of the air chamber is 4.5kpa ～ 5.5kpa,the speed of the seeding shaft is 30 ～ 35 rad / min,the diameter of the hole is 10 ～ 12 mm and the number of holes When the number is 10-12,the qualified index for seeding is higher than 91%,the missed index is lower than 6.5%,and the replay index is lower than 2.5%.(5)Determination of dimensional expressions of various parameters and seeding performance of the seeding device.According to the influence of the changes of various factors under the normal working state of the seeding meter on the qualified index,missed seed index and replay index,a multivariate analysis of the test results has determined.we can get the mathematical expression of the dimensional relationship between the seeding device quality index and each factor.It can provide a reference for the application of dimensional analysis in other aspects. |
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