Design And Experiment Of The Stalks And Leaves Cleaning Device For Fresh Maize Harvester

Fresh corn is popular with a unique delicious taste of sweet and soft waxy,rich in nutrients.Nowadays in China,the development level of fresh maize harvester is also increasing day by day.However,most of the relevant research is focused on the head.The impurity content of stalks and leaves in maize ear harvester by head is often too high,which brings a great deal of trouble to the subsequent processing and edible treatment.At present,centrifugal fan is often used to remove stalks and leaves.However,there are many problems to use it to remove impurity from fresh corn ear,such as large space occupation,difficult installation,easy clogging of operation,poor effect of debris crushing and recovery,and so on.There are also the use of negative pressure axial flow impurity removal device to seed corn ear for miscellaneous removal.However,physical characteristics of the seed corn are different from those of fresh corn.So the air separation device is not suitable for fresh corn with high water content.Therefore,it is of great practical significance to study and design a kind of stalks and leaves cleaning device suitable for fresh maize ear harvester to solve the problem of high spikelet content and so on.In order to solve the problem of more impurity of stalks and leaves in maize ear harvester,a kind of stalks and leaves cleaning device was designed by analyzing and summarizing the research results of stalks and leaves cleaning device of fresh maize ear harvester at home and abroad.The research of key technologies was completed by determination of mechanical properties,theoretical analysis,virtual prototype design,numerical simulation,software analysis and test of bed.It provides references for the further development of fresh maize ear harvester.The main contents and conclusions of the study are as follows:(1)Determination of physical characteristics of fresh corn: the basic parameters and mechanical characteristic parameters of stalks of fresh corn were measured,and the basic physical parameters of fresh corn ear were determined by using three kinds of fresh corn,namely Jingkenuo 2010,Wucainuo and Cuiwang.The results of measurement provide references for the design of the key components of the stalks and leaves cleaning device in fresh maize harvester.(2)Design of stalks leaves cleaning device: the general structure and working principle of stalks leaves cleaning device are described.The main structural parameters and working parameters of the key components are determined by the design calculation and analysis.The three-dimensional model of the device is established by using the Solid Works.The overall design scheme of the stalks and leaves cleaning device is determined and its working principle isanalyzed.(3)Flow field analysis of straw and leaves cleaning device: the flow field of stalks and leaves cleaning device is simulated and analyzed by ANSYS Fluent software,and the turbulence model is established.The pressure cloud diagram,velocity vector diagram and shear rate diagram are obtained,and the results are analyzed.The optimum circumferential four blades is obtained by comprehensive optimization,the flow field stability is the best,the dynamic balance is the best,and the shear rate is relatively large.The results of test of bed show that the measured values are basically consistent with the numerical simulation values.(4)Finite element analysis of key components of stalks and leaves cleaning device: the simulation analysis of key components(fixed knife,rotating knife and fan impeller shaft assembly)is carried out by using ANSYS Workbench software.Finite element statics simulation and modal analysis are carried out for the weak parts fixed knives and rotating knives and fan impeller shaft assembly.The results show that the stress and strain of the weak links of the fixed knives and the rotating knives are concentrated within a reasonable range,which satisfies the strength.The modal analysis results show that the excitation frequency of the system is far less than the natural frequency of the fan impeller assembly,and the possibility of resonance is not great,and the stability of the operation is well.(5)Test of bed of stalks and leaves cleaning device: for the study performance of cleaning device,taking the speed of fan,overlapping length of rotating and fixed knife and material conveying speed as the factors,taking the rate of trash and the qualified rate of stalk chopping as the evaluation index,the optimization test is carried out and an optimum combination of structural parameters and motion parameters of the cleaning device under different conditions is obtained.The results show that: for the mature fresh maize,when the speed of fan was 1956~1998 r/min,overlapping length of rotating and fixed knife was 26.90~29.92 mm,and material conveying speed was 0.59~0.83 m/s,the corresponding rate of trash was 0.56 %~0.59 %,as well as the qualified rate of stalk chopping was 88.59 %~89.27 %.It provides guidance for the design and production of cleaning device for the fresh maize harvester in practice.