Design And Experimental Research On Tangential And Transverse Axial Flow Threshing System Of Windrow Harvesting For Buckwheat

Buckwheat is rich in nutrients,has high medicinal value,and has outstanding health care functions.It is an internationally recognized medicinal and edible multi-grain crop.In recent years,domestic and foreign market demand has increased year by year.Due to the inconsistent maturity of buckwheat and the material characteristics of mature seeds falling off easily,mechanized harvesting has the problems of high harvest loss rate,easy clogging of threshing drums,high seed crushing rate and high impurity rate.The threshing and separating device is an important part of the combine harvester,and its performance has an important influence on the harvesting effect such as the threshing loss rate,crushing rate and cleaning impurity content.In this paper,based on the study of the characteristics of buckwheat materials,the threshing model of the tangential-horizontal axial flow threshing system is established.The model is used to simulate and analyze the existing tangential-horizontal axial flow threshing device.The device has been improved in design;using test analysis methods such as bench test and high-speed photography,the improved cutting-transverse axial flow threshing system has been analyzed and operated,which shows that the device meets the buckwheat harvesting requirements.The main research conclusions are as follows:(1)Research on the characteristics of buckwheat grain and stalk materials.The buckwheat harvest period and the morphological characteristics of buckwheat plants were analyzed;physical characteristics such as triaxial size,thousand-grain weight and density of different buckwheat varieties were tested,and the compression and shear resistance of the seeds and the different positions of stalks(inflorescence stalks and branches),Branch and main stem,upper main stem,lower main stem)mechanical properties such as shear and tensile strength.(2)Analysis of mathematical model for buckwheat threshing and separation.Based on the material characteristics of buckwheat,the mathematical model of tangential-horizontal flow threshing and separation was analyzed and improved,and the improved model was used to simulate and analyze the existing tangential-horizontal flow threshing test device.1.The principle of weakening threshing The threshing-transverse axial flow threshing device was improved.(3)Based on the material characteristics of buckwheat,the above-mentioned simulation analysis and improved design,the existing cutting-transverse axial flow threshing test device was modified.The device is mainly modified with rod tooth shear flow threshing drum,rib bar type horizontal axial flow threshing drum,punching gravure screen and threshing top cover.The bar-tooth cut-off threshing device performs preliminary threshing of the buckwheat material,the stalk-shaped horizontal-axis threshing device finally threshs at the second time,and the punched gravure screen reduces the threshing strength to improve the buckwheat threshing and separation operation effect.The overall structure of the threshing system of the test device is modular in design,which is convenient for replacing key components such as threshing drums or parameter adjustments,so as to carry out threshing test research for various crops.(4)Bench test study on buckwheat demining.In the modified test device,single factor test and orthogonal test were used to study the moisture content,threshing gap,threshing drum rotation speed and feeding amount of buckwheat grains.The rule of influence of the operating parameters such as operation parameters;research and analysis of the distribution of the buckwheat material along the direction of the demineralization and the proportion of each component of the demineralized material after demineralization;the high-speed photography technology was used to observe and analyze the movement trajectory of the demineralized buckwheat material.The order of factors and optimal parameter combination that affect the threshing operation are obtained: the grain moisture content is 20%,the threshing gap is 35 mm,the threshing drum rotation speed is 600 r/min,the feeding amount is 1.2 kg/s;The flow-cutting threshing device mainly performs preliminary threshing of the easy threshing grains and separates the fallen grains wrapped in the material.The first half of the ribbed horizontal axial flow threshing device mainly carries out threshing and separation of buckwheat materials,and the second half mainly crushes Break buckwheat stalks and discharge threshing device.Through the above-mentioned experimental research,it can be known that the de-separation test device has good performance and meets the de-separation operation requirements of buckwheat.