| The pneumatic conveying system is an important part of cotton harvestingmachinery, the working performance of the pneumatic conveying system has animportant influence on the whole system. The working principle of the pneumaticconveyance system is: the "vacuum" area that is formed near the mouth of the jet isthe result of the high-speed injection of the positive pressure airflow which comesfrom the blower. Seed cotton in the receiving room with the air is inhaled pipeline bynegative pressure. The pressure from receiving room to jet mouth is negative,however the pressure from jet mouth to outlet of the pipeline is gradually becomingpositive pressure, and the seed cotton will be transported to the collection of cottonbox in the last.The data of cotton harvesting machinery whether from domestic or overseas isvery limited. The numerical simulation technology is used in this paper. Not only dowe understand the state of the internal pipe flow, but also find out characteristics andlaws in the flow field distribution, through the numerical simulation that is in differentconditions by the software FLUENT, which will be the necessary basis of the wholemachine designed.This paper mainly studies several aspects as the followings:(1) According to the specific requirements of the cotton harvesting machinery,the related parameters of the choice, analysis and calculation should be done.Thusobtaining the cotton pipe entity3D model.(2) According to the basic characteristics of multi-phase flow, the Eulerianmodel is selected in the simulation of gas-solid two-phase flow the numericalsimulation method includes: the finite volume method and k~ε model.(3) To obtain Velocity field and pressure field, single-phase and gas-solidtwo-phase flow will be done by using FLUENT software, taking the simplification of3D model and the boundary conditions into account. (4)To some extent, through the improvement of cotton pipe model, eddy cavitiesare diminishing, but the transmission efficiency of cotton is improving. |
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