小麦育种单穗电动脱粒机设计与试验OA北大核心CSTPCD

[Objective]A portable electric wheat-breeding single spike thresher was designed to solve the problems of wheat breeding single spike harvest,heavy sampling workload and inconvenient real-time sampling in the field.[Method]The single grain thresher adopts the design of coaxial threshing plate and cleaning fan,U-shaped cleaning duct and adjustable cleaning air volume.The structure of threshing plate,speed of threshing plate,diameter of cleaning fan,number of blades and wind speed of fan are determined.Cleaning performance tests were conducted using computational fluid dynamics(CFD)for a minimum inlet wind speed of 5 m·s-1 and a maximum inlet wind speed of 10 m·s-1.From the simulation,it can be seen that the wind speed in the cleaning area is lower than the suspension speed of wheat grains and higher than the suspension speed of impurities,which can meet the requirements of wheat cleaning.A wheat plant model was established using the discrete element method(DEM)and multi-scale particle aggregation method;Through simulation experiments,the variation of speed and displacement of wheat grains in the threshing machine over time,and the problem of seed lag were analyzed.[Result]A three-factor and three-level orthogonal test was designed to study the effects of cylinder speed,feeding amount and concave gap on seed stagnation of thresher.The results of range analysis showed that the main and secondary order of the seed stagnation rate was cylinder speed＞feeding amount＞concave gap.The working parameter combination with the smallest seed stagnation rate was drum speed 1 000 r·min-1,feeding amount 3 panicle·time-1 and the gap between the concave plates is 6mm.On the basis of single spike electric threshing machine samples in wheat breeding,experimental verification was carried out,and the results showed that the threshing machine did not have seed lag phenomenon,and the impurity content of the extracted grains was 0.83％.[Conclusion]The wheat breeding single spike electric thresher has good threshing performance without seed lag problems,and can meet the requirements of wheat breeding single spike threshing.