Screening Performance Research And Optimization Of The Plot Combine Harvester Based On EDEM

The plot combine harvester should keep high cleaning percentage,low loss rate and low residual rate to make sure the accuracy of the seed-breeding test date after it accomplished seedharvesting.Therefore,it has a positive meaning to research methods to improve the cleaning performance and design a cleaning device of the plot combine harvester which is suitable for seed-breeding test.Firstly,this thesis studies the screening efficiency,cleaning percentage and loss rate based on vibration screen of the plot combine harvester designed by our program team,uses these indicators to reflect the cleaning performance,and analyses parameters of the vibration screen which affect the screening efficiency,cleaning percentage and loss rate.Then,this thesis establishes the virtual screening model by Creo software,and doses the single factor and uniform simulation test based on EDEM software.Finally,this thesis doses the regression analysis and parameter optimization for the main factors.The main work is as follows:(1)The study of the screening theory of the plot combine harvester.Earlier in this thesis the working process of the plot harvester vibration screen was outlined,and the movement of mixture on the sieve was analyzed.Parameters of vibration screen that affect screening performance based the theory of screen-penetrating probability was obtained as follows: vibration frequency,amplitude,vibrating direction angle,shapes of the mesh,inclination of sieve cover,mesh size,mesh distance.(2)Simulation test of screening factors based on EDEM software.In the middle of this thesis the single factor simulation test was did based on EDEM software,and the relationship of parameters and the screening efficiency,cleaning percentage and loss rate was obtained.(3)The regression analysis and parameter optimization of screening performance.Last in this thesis the relationship of parameters and screening performance was analyzed,and vibration frequency,amplitude,vibrating direction angle and inclination of sieve cover were selected for the uniform simulation test.The regression model of screening performance with the 4 parameters was established.A set of best parameters(vibration frequency 3.3Hz,amplitude 30 mm,vibrating direction angle 10° and inclination of sieve cover 4.6°;screening efficiency98.59 %,cleaning percentage 95.56 % and loss rate 0.82 %)was obtained after optimized,when the value of parameters range are: vibration frequency 3.3~5.8Hz,amplitude 30~50mm,vibrating direction angle-10~10° and inclination of sieve cover-25~25°.