| China,as the world’s largest agricultural country,its crop yields has been increased every year,which led to a extremely increase in the amount of crop straw.Especially,corn as one of the major crop,production of crop straw is relatively high when compared with wheat and rice,besides,corn straw are more difficult to handle.At present,utilization rate of corn straw in China is not true effective,it is burned in fields at many cases,which not only caused serious pollution to the environment,but also a lot of waste of corn straw resources.Currently,straw returned is the most effective and convenient way to deal with it,it can increase soil fertility,enhance soil organic matter content and avoid soil erosion,while it can also promote the sustainable development of agriculture and solve environmental pollution problems caused by burning crop straw.In this paper,diversion device of straw-returning machine was studied aimed at the characteristics of the planting pattern in the area of northeast China,this study based on the research of domestic and foreign research results of straw returning machine.The ways of theoretical analysis,device design and experimental research were used.The working contents and results obtained are as follows:(1)The theoretical analysis on operating mechanism and knife rolling of corn straw-returning machine were taken.The appropriate knife of type Y was selected through the contrast and force analysis of rejection knife.The distance was 10 cm between straw and straw-returning machine was obtained through the analysis of the rotational speed of knife and the crushed straw,which provided the theoretical basis for the design and experiment of the diversion device.(2)In order to realize the diversion effects for crushed straw,a straw diversion device was designed.Combined with theoretical analysis and practical needs,each structure of the diversion device was designed;The three-dimensional model of the diversion device is introduced into the EDEM software,and the discrete element simulation is carried out to test whether the design is reasonable,which satisfied the overall structure and performance requirements;To optimize the diversion device for processing,assembly.(3)The angle between the vertical and horizontal plate,the distance between the diversion device and the rear frame,the speed of the machine were used as experimental factors to conduct field experiment on the diversion device.Firstly,the field test was carried out for the rotation direction of knife-cylinder and obtained the best rotation direction under this testing machine condition.Secondly,field single factor test was studied and got the best range of factors.The range of angle between the vertical and the horizontal plate was 50° to 900°,the range of distance between the diversion device and the rear spar was 5 cm to 15 cm,the speed of the straw-returning machine was 0.91 m/s to 1.82 m/s.Thirdly,the three-factor quadratic regression combination test design was used to analyze the variance and regression by the test data through using Design-expert.The regression model equation for the rate of straw into the ditch was gotten through changing the angle between vertical and horizontal plate of the diversion device,the distance between diversion device and machine rear frame and the working speed of machine,and the interaction effects between the factors was analyzed.According to the analysis of variance,the influence degree of each factor on rate of straw into the ditch is that the distance between the vertical and the horizontal plate,the distance between the diversion device and the machine rear frame>the working speed of machine.(4)The parameters of diversion device were optimized by Design-expert,and the optimal parameters of the diversion device were determined by considering the influence of practical working performance.The angle between vertical and horizontal plate was 64.67°,the distance between diversion device and machine rear frame was 9.56 cm,and the working speed of machine was 1.53 m/s.The experimental results showed that diversion device had an extremely influence on the rate of straw into the ditch by validation and comparison test in fields with the results of optimization.The research in this paper provided a new support and method for designing and research of straw-diversion device,and provided reference for the research of the straw-diversion device which could promote the further development of the mechanized straw returned. |
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