| The cotton planting area ranks first in the world, but most of picking operation is manual mode. This is lagging far behind other countries in the word. There are some problems, which prevent the wide spread of the mechanical picking, more or less in recent years from abroad and self-developed cotton-picker. So, the market needs a kind of high picking efficiency, low cost and portable of cotton-picker. The brand of X portable cotton-picker can meet the demand of the market better, but it is the problem that low efficiency and cotton into fan can’t discharge timely.In this paper, using commercial CFD software FLUENT to simulate the brand of X portable cotton-picker fan. And adopting the results combined with the related theory knowledge to optimize the structural parameters of the impeller and the exit of the fan. The main work and results in this paper are as follows:(1) It completes the test for the performance of the cotton-picker fan, establishes the3-dimensional model of the fan, meshes the calculation zone, researches and determines the turbulent model and solution method for the numerical simulation of flow field in the fan and completes the3-Dimensional Numerical Simulation of the fan. Besides, the accuracy of the numerical simulation is verified by the result of the test.(2) This paper analyses the flow pattern of the inner flow field carefully, which forms a whole understanding for the fan, and analyses for the flow field and pressure grooves detailedly, finally comes to a conclusion that it has an important role for the cotton’s flow in the fan. In this paper, I will not make a optimize conclusions on boss temporarily. Besides these, this paper also analyzes flow field inside of the fan outlet, and comes to the conclusion that the cause of the poor outlet flow field may be caused by strange ways of fan outlet.(3) By using the principle and method of orthogonal test, choosing blade entrance angle, outlet angle, thickness and number of leaves of impeller as factors and four different levels of every factor, makes the fan efficiency as the main target and total pressure to optimize the structure parameters of the fan impeller. After this way, the fan efficiency has been improved significantly, but the outlet flow field has no obvious improvement. Finally, the export flow fan is optimized by changing the volute outlet. After optimal, the fan efficiency than the original fan has improved3.67%, total pressure has increased36.95%than that of the original fan, the outlet flow field of fan is improved obviously and the problem of poor cotton outflow is solved. |
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