Design And Research Of The Pneumatic Conveying Mechanism On Coupled DEM-FLUENT

The field breeding mechanization can improve the operation efficiency, unify the operation technical indicators, lower the labor intensity, and reduce the field breeding test error and improve the quality of the breeding. Plot wheat combine harvester is an indispensable part of the field breeding mechanization, which is an important part of the field among breeding seed harvest links. According to the strict agronomic requirements, this paper focuses on study and design of the pneumatic conveying mechanism of plot wheat combine harvester by using EDEM-FLUENT gas-solid coupling.The pneumatic conveying mechanism was designed on the basis of the pneumatic conveying venture tube theory formula, then according to the actual situation, coupling simulation test was set to the euler-euler double fluid coupling model, which the gas phase simulation was set to the transient pressure solver and Realizable k/epsilon model, the solid phase was used the discrete element model for coupling simulation test, which obtained a real pressure distribution, velocity distribution and particle trajectories in the pneumatic conveying device. This study finds that the pneumatic conveying device’s nozzle can form stable high jet on the flow field, the particles can quickly to be transported, but due to the nozzle has a certain scope of jet, the larger velocity particle that comes from the wall cannot transport to the mixing chamber, which will easily forms residues in the corner.According to the strict agronomic without residue requirements, a more optimal structure was designed based on the theoretical value which the circular tube was changed to square tube by analogy method. In order to avoid residue, the high pressure nozzle structure was changed into a gradient structure which directly connected to the set food fight, and at the same time the new structure coupling simulation experiment was carried out by using the orthogonal test. In view of the complex factors which affected the effect of pneumatic conveying device, this research takes four of the major factors—wind pressure, nozzle length, nozzle height and mixing height as the research object by adopting the same processing method before and using the orthogonal table to design simulation experiment of 9 groups of model. Through the comparison analysis of the results and the method of analysis of variance to get a set of optimal solutions, the new structure which the circular tube was changed to square tube by analogy method has been proved to be feasible.