| The centrifugal fan is the machinery which relies on the input mechanical energy,improves the gas pressure to send gas. The centrifugal fan is widely used in the life ofnational production, coal mining, the construction industry, steel, power generation andagriculture and other fields. Impeller and the blade is the working parts of the centrifugal fan,its intensity affect the safe operation of the fan, its structural parameters play a decisive role inthe fan overall performance. The conventional method the strength of the impeller and theblade is smaller than the actual value. Sometimes the fans would be broken. The centrifugalfans are usually designed with the similar design method, there was no optimization of thestructural parameters of the fan, fan performance is not ideal. In this paper, modern designmethods will be used in impeller and blade strength calculation, the optimization of structuralparameters and flow field simulation that provide a reference for the design and improvementof the centrifugal fan.(1)The centrifugal fan of a rapeseed sorter machine is used as the research object.According to a fan parts manufacturing drawings, the3D model of centrifugal fans parts andthe flow field were created and assembled in Pro/E.(2) Static analysis of the impeller was completed with finite element analysis softwareANSYS, gained the impeller stress and strain contours. Comparing finite element analysisresults with the results of the traditional method, verified the limitations of traditionalcomputing methods. The two calculation methods showed that the fan impeller to meet thestrength criteria.(3) Modal analysis of the impeller was finished with ANSYS, gained the eighth ordernatural frequencies of the impeller and corresponding vibration graph. Because the impeller ofthe interference frequency is less than the natural frequencies of the impeller, so the impellerwill not occurred resonance.(4) The optimization model of the variable to the flow was established, in which powerloss was objective function and the structural parameters of the impeller were variable. Theconstraints were established with the theory of centrifugal fan. The impeller structuralparameters were optimized with the toolbox of MATLAB software. The minimum streampower loss and the impeller structure parameters were gotten. The loss reduced from 110.13Pa to75.51Pa. Optimization results indicate that the optimal design method used incentrifugal fan design can effectively improve the fan performance.(5)The internal flow field of centrifugal fans is simulated with the CFD softwareFLUENT. The numerical analysis result about the full flow field simulation was calculated inthe FLUENT. The pressure contours and velocity vector of the fan internal flow field wouldbe gotten. The calculated results would be helpful to descript the air flow of the fan, predictthe actual performance of the fan. The calculation results can provide a reference for thedesign and improvement of centrifugal fan. |
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