The Numerical Research On Performance Effect For Design Elements Of Flow Fans

Axial flow fans have extensive application in industry and life, they also consumeabundant energy. As our country is under increasing pressure of environmental governance,energy conservation and emission reduction, fan industry focus on the fields which areresearching, developing and using high-efficiency fan products. The T35axial flow fan isa kind of ventilation product used for many years in our country, its application range alsois very wide, but the existing T35fan efficiency is still not high. Based on the currentsituation of inefficient T35axial flow fan, this article developed the new T35axial flow fanby using engineering design experience and modern design methods and studied theperformance effect of several important design elements for it.Firstly, this article introduced engineering method of axial flow fan pneumatic designespecially including vane design, then described the whole machine three-dimensionalflow field numerical simulation method in conducting fan aerodynamic performancesimulation, including numerical modeling, meshing, boundary conditions, convergencecriterion and so on, and further discussed the performance calculation results difference ofthe fan under different numerical modeling, different fan outlet static pressurepost-processing and different boundary condition settings. The numerical simulationresults can be compared with the measured results by adopting the appropriate modelingand numerical simulation post-processing. The whole machine numerical simulation gridsof the fan is obtained by grid tests, so it is of important foundation for subsequentdiscussing performance effect of the T35axial fan’s design elements.Secondly, the article got a new T35axial flow fan design prototype on the basis of theexisting T35axial flow fan, meanwhile improved input format, output format andpartial experience parameter settings for the existing pneumatic design procedure. Theimproved procedure not only has the characteristics of high-efficiency and flexibility, andit can primely link up subsequent numerical simulation. On the basis through conductingthree-dimensional numerical simulation of the new T35axial flow fan, this article studiedfan performance effect because of the fan’s design elements such as hub ratio, flowcoefficient, forward lean, forward swept and so on.Finally, through the above research, the conclusions are: Firstly, fan pressure increases slightly at first and then decreases with the increase of hub ratio, fan efficiency graduallydecreases by and large with the increase of hub ratio. Secondly, fan pressure increases atfirst and then decreases and increases at last with the increase of flow coefficient, fanefficiency increases at first and then decreases with the increase of flow coefficient. Thirdly,fan pressure and fan efficiency decreases with the increase of forward lean angle. Finally,fan pressure decreases slightly at first and then increases and decreases at last with theincrease of forward swept angle, fan efficiency volatility decreases with the increase offorward swept angle. Through the analysis of the above design factors, the conclusions are:the T35axial flow fan’s best design is that hub ration should be0.35, flow coefficientshould be0.1, forward Lean blade is not suitable for it, forward swept blade is suitable forit. The performance of the T35axial flow fan in the design scheme is better than the oldT35axial flow fan, the results show that total pressure is increased by36.3Pa and totalpressure efficiency is increased by5.3%.