Convery Performance Research & Optimization Of Grain Convery Screw Based On EDEM

Realization of grain harvesting mechanization is an important way to achieve agricultural modernization&to solve the "Three Rural Issues". In the grain harvesting operations, combine harvesters was extensively used,and grain convery screw in combine harvesters are widely used to convery and elevate grains,its performance is important factor to determine the efficiency and quality of grains harvested. However, the convery efficiency of grain convery screw in combine is not high enough,and also with energy consumption as well as grain fragmentation and other problems. The reason is that the design means of grain convery screw is relatively backward and the prototype tests by seasonal restricted, etc.Therefore, it is necessary to use some modern design and experimental methods to reserch and optimize the convery performance parameters.In this thesis, the object of study is grain convery screw in combine harvesters& the goal is the convery performance,which is measured by convery efficiency ? energy consumption and the probability of grain fragmentation. With discrete element method as the theoretical basis,using EDEM software and orthogonal experiments as the tools, the influences of these four factors which are horizontal screw rotation,vertical screw rotation,wheat's filling rate and the screw diameter to the convery performance was Studied on.Fnally getted a set of optimal parameter combinations. Simulation results showhat using the Discrete Element Method combined with orthogonal experiment this kind of research means for studying and optimizing harvester grains convery equipments is feasible.Working mainly as follows.(1)Cnvery mechanism of grain convery screw was analyzed, convery efficiency,energy consumption and the probability of grain fragmentation was determineed to measure the convery performance. In the meantime, new research methods for different indicators was presented combining with discrete element theory and EDEM features.Finally, the parameters of grain convery screw was determined combining with the antual requirements.(2) Single factor experiment of the above-mentioned 4 factors was down in EDEM by importing 3D models of grain convery screw created in Creo&creating wheat's simulation model in EDEM.Finally we getted the relationships between the 4 factors and the 3 goals,and then the levels of factors used for orthogonal experiment was determined.(3) Orthogonal experimental was down in EDEM and we getted the primary and secondary of the 4 factors and the optimal factor level. The optimal parameters level combination was determined combining with the practical requirements,and simulation verification was down in EDEM with optimal parameter combination, by comparing theresults before and after optimization, we found that under the condition of invariable other parameters of grain convery screw,through the way of increasing wheat's filling rate and a moderate amount of reducing screw diamete, the optimized comprehensive convery performance were improved.