Noise Reduction And Efficiency Increase Research On The Blade Of Bionic Coupling Axial Fan Model

Noise pollution, air pollution and water pollution have been identified as the three major sources of pollution in today's world. Reducing the noise pollution is the most important aspect to improve the quality of the environment, which plays an important role in the production and life. As mechanical equipment of industrial and agricultural production and people's daily life in a wide application range, the operated noise of fan has become an important composing of industrial noise. The aerodynamic noise run accounted for more than 45% of the fan operation noise. Moreover, how to control the aerodynamic noise of fan effectively has received considerable attention in the academic and industrial sectors. The excellent fan not only requires the lower fan noise, but also the higher efficiency. Therefore, through increase the level of research and design, we should control the noise of the axial fan and keep the higher effiency, which has most important significance for national economy development, energy conservation and environmental protection.In the millions of years evolution, biology through the natural selection have a lot of amazing characteritics to adapt to the natural environment. With the continuous development of bionics, a large number of scientific research found that the biological function was the result of synergistic effect of sevel factors such as morphology, structure and material. Since the beginning of the last century 80's, the Ministry of Education Key Laboratory of Bionics Engineering in Jilin University make a large number of biological research, and combinate with engineering applications to solve many practical issues to be settled urgently. In 2006, a clear concept of the biological coupling was definited and biological coupling theory was first proposed under the leadership of Professor Ren. Subsequently a lot of biological coupling characteristics research carry out to applied to engineering practice.The study in this paper is to use the coupling characteristics of the owl's silent flight in the field of noise control and to improve the fan's performance. The paper based on the theory of biological coupling and axial fan aimed to reduce noise and increase efficiency of the fan through controlling the turbulent boundary layer. The study perform a model orthogonal test which have biological coupling characteristics and analyse the test result that combinate with numerical simulation to get the mechanism of the noise reduction and efficiency increase.The basic work of this paper is the analysis of the coupling characteristics in biology. Because of the silent flight of the owl, we have analysed the coupling characteristics of the owl and then found that the stripe structure between the owl's feather,sawtooth shape at the end of the feather and microstructure of the small feather branch are main factors which affect owl'silent flight..Acording to the theory of the biological coupling, we consider that the main coupling element are stripe structure and sawtooth shape in the surface feature of the owl, and the second coupling element is the microstructure of the small feather branch.The aerodynamic noise test of the blade of bionic coupling axial fan model shows a good noise reduction efficiency. According to the result of the experiment, we analysis the aerodynamic noise influenceing factors for the blade of bionic coupling axial fan model and then find that the length-width radio of the stripe structure is the most significant factor. The shape of the stripe structure also play an important role in the noise reduction, which has great influence for the aerodynamic noise. From the optimization results, the U-shaped blade of bionic coupling axial fan model has the best noise reduction effect. Generally speaking, the influence of the sawtooth shape is less than stripe structure for the aerodynamic noise of the axial fan, but is also a factor that can not be ignored. In addition, the smaller size of the sawtooth also will have a better noise reduction effect.The performance test of the blade of bionic coupling axial fan model through study the performance parameters shows that the blade of bionic coupling axial fan model has good performance when get a noise reduction effect. Furthermore, some the blade of bionic coupling axial fan models increase the efficiency. According to the result of the experiment, we analysis the performance influenceing factors for the blade of bionic coupling axial fan model and then find that the width of the sawtooth and stripe structure and the distance of the stripe structure are significant factor. The sawtooth shape and stripe structure all have an important influence for the blade of bionic coupling axial fan model.After extracting the main coupling characteristic of the owl, we design the 3D blade of bionic coupling axial fan model by Mastercam and make a numerical simulation. We get the flow field features around the fan model through the numerical simulation, which get ready for further analysis and prediction of the fan's noise and performance.The study of this paper is only the part of the noise reduction and efficiency increase research on the bionic coupling for the blade of axial fan model. It still requires further analysis and the establishment of mathematical models to meet the needs of engineering applications.