Design And Experimental Study On Dust Removal Device Of Straw Feed Harvester

China is rich in straw resources,accounting for about 25%of the world’s total straw.As an important feed source crop,corn stalk yield is huge after harvest,with an annual yield of about 200 million tons.Converting abundant straw resources into forage can not only solve the problem of forage shortage in animal husbandry,but also improve the environmental pollution caused by straw burning.Straw harvester will mix dust into straw feed in the process of picking up and harvesting straw,resulting in poor feed quality and affecting palatability of livestock.In this thesis,a roller type dust removal device is designed for straw feed harvester,the relevant characteristic parameters of straw feed and dust are obtained and calibrated,and the dust removal effect of dust removal device is numerically simulated by discrete element method,and the optimal structural parameters of dust removal device are selected.Field experiments were carried out to verify the rationality of the structure of the dust removal device and the accuracy of the discrete element numerical simulation parameters.The specific research content and results are as follows:(1)Aiming at the problem that there is a lot of dust in the straw feed harvester after harvest,a roller type dust removing device is designed,which is mainly composed of dust removing drum and dust removing screen,and the main working parts of dust removing drum include trapezoidal knife,drum and drum shaft.In order to explore the key factors affecting the dust removal effect of the dust removal device,the force and movement of straw feed in the dust removal device were analyzed,and it was concluded that the key factors affecting the dust removal effect were the rotation speed of the dust removal drum,the aperture of the dust removal screen and the number of dust removal drum.(2)The relevant parameters of straw feed and dust were calibrated by combining physical test with EDEM discrete element numerical simulation.EDEM software was used to establish the particle model of straw feed and dust.By measuring the repose Angle of straw feed and dust particles,the relevant numerical simulation parameters of straw feed and dust were calibrated.Determined the relevant numerical simulation parameters of straw feed and dust,Dust contact model JKR surface energy 9.052J/m~2,dust-dust recovery coefficient0.52,dust-dust rolling friction coefficient 0.182,dust-steel rolling friction coefficient 0.125,dust-steel static friction coefficient 0.85,dust-skin rolling friction coefficient 0.35,dust-skin static friction coefficient 0.55,dust-Internal friction coefficient of rolling 0.45,dust internal static friction coefficient of 0.75,dust-dust static friction coefficient of 0.74,dust-steel collision recovery coefficient of 0.35.(3)The above parameters are used to carry out the numerical simulation dust removal test of the dust removal device.The rotating speed of the dust removal drum,the aperture of the dust removal screen and the number of dust removal drum are taken as the test factors,and the impurity rate is taken as the evaluation index to carry out the three-factor and three-level orthogonal numerical simulation dust removal test.The experimental results show that the optimal structural parameters are the rotation speed of the dust collector 370r/min,the mesh aperture of the dust collector 5mm and the number of dust collector rollers.Under the optimal structural parameters,the impurity rate of the numerical simulation test is 5.9%.(4)According to the optimal structure parameters obtained from the numerical simulation dust removal test,the dust removal device was processed and field validation test was conducted.The impurity rate obtained from the field test was 6.5%,and the relative error was 9.23%from the numerical simulation test,which verified the rationality of the structure of the dust removal device and the accuracy of the calibrated numerical simulation parameters.