Simulation And Test Of Potato Seedling Crushing And Throwing Device Based On Fluent-EDEM

As one of the most important parts of the world's leading crops,the planting area of potato is becoming larger year by year.At the same time,its straw which has an extensive application prosperity for biomass energy,organic manure,and animal feed is a significant agricultural resource.Now manual harvest and returning still occupies a large proportion of potato planting industry in domestic,which leads to poor effect and high cost.Simultaneously,with the throwing away of straw,the environmental pollution and waste of organic fertilizer resources would be carried out.Therefore,a high-efficiency processor for potato's straw is needed to deal with the returning problem.On the basis of the research about characteristic of potato' straw,a processor which can cut off main stem of potato seeding and collect whole plant is designed.To give full play to device's throwing ability and improve crushing and throwing rate,a method of integrating theoretical analysis,Fluent-EDEM Coupling simulation and experiment is applied.The paper mainly includes following research contents:(1)Measurement of the characteristic of potato's straw.The material characteristic parameter in harvesting period is measured by experiments.Macroscopic property,filling characteristics,contact characteristics and mechanical properties is researched,which informed designing of rate about crushing knife shaft,the simulation of cutting process and throwing process.(2)Designing of potato straw recovery processor.Interworking of rolling cutting device and fixed blades is used to calculate reasonable rotation speed of crushing blades.To ensure the throwing effect,length of broken stem is 30 mm,and minimum speed of cutting blades is1700r/min.To ensure the throwing rate,maximum distance of throwing channel is 1.15 m,and width of throwing channel is 0.25 m.To ensure the reliability of blades in cutting process,explicit dynamic is used to calculate maximum principal stress,which shows that the stress value is within allowable stress range of material and the processor is structurally stable.(3)Flow field simulation of potato seedling crushing recovery device.After calculating the flow field of device,and researching change of velocity field,a consequence shows that fluid flow at the entrance of crushing and throwing device is relatively stable.When the fluid flows into rotating area of crushing knife,the flow becomes disordered and flow velocityincreases significantly.Flow velocity at exit is stable,which can play a good role in crushing potato seedlingsthe larger the rotating speed of crushing knife is,the more blades there are,and the more stable wind speed is.(4)Research of grinding potato straw particles in the throwing device.The Fluent-EDEM coupling is used to study characteristic of particles' motion in the throwing device,which shows that After the formation of crushed potato seedlings will move in crushing chamber with crushing knife,in which a large number of particles will enter throwing channel from crushing chamber and be thrown,while a small number of potato seedlings will enter throwing channel after rotating in crushing chamber for a period of time.Simulation results were studied by method of variance analysis and regression equation fitting.It is concluded that the device can give full play to its throwing ability when feeding capacity is 3.8 kg/s,crushing knife is 12 pieces and rotation speed of cutter shaft is 2100 r/min.(5)Experiment of crushing and throwing device.Using method of three-factor and three-level center combination test,a quadratic regression model was established with machine speed of grinding blade rotating speed as test factor and throwing efficiency of crushing qualified rate of potato seedlings as test index,and the influence of each test factor on test index was obtained.Through the calculation of optimization module and verification of field test,optimal working parameter combination is that number of crushing blades is 12,spindle speed is 2060r/min and forward velocity is 0.6m/s,which can ensure qualification rate of straw chopping reaches 93.282%,and recovery rate reaches 92.728 %.