Study Of Noise Reduction On Fan Vane With Bionic Structure

As air and water pollution, noise has become another serious contamination. Noise reduction is of great significance to production and life. Fans have been in common used in the production and life, fan noise pollution is the major source of noise in factories and residence, thus reducing fan noise is of great significance for the control of noise pollution. In addition, the fan noise is the main source of noise of submarines. Submarine fan noise reduction is important for improving the submarine's concealment.Fan noise includes mainly mechanical noise and aerodynamic noise. Mechanical noise is the vibration noise by the impact of fan's moving parts, friction and uneven. One source of aerodynamic noise is the impact and friction between air flow and blades, the other is the interaction between the different airflow. Aerodynamic noise controlled difficultly is the main part of fan noise. Mechanical noise is a minor part of the fan noise,it can be reduced better through reasonable control of the design and installation of precision machining.Through Animal studies on the long-term soil beetle, Jilin University, the Ministry of Education Key Laboratory for terrain-machinery Bionics engineering have found that these animals showed equivocal profile surface shape, convex hull shape and form shaped craters, these special surface structures are good exercise to reduce noise and resistance functions. Thus, the laboratory put "non-smooth surface" conception, establish the reduction soil conglutination and resistance theory, and make the application extension of non-smooth theory expand to water, gas and fluid drag reduction of noise reduction research.The fish swimming in water and birds flying in air possess the properties of low noise and low resistivity. Analysis of the structural characteristics of birds and fish, birds and fish found showing non-smooth surface with a wide array of features. The leading edge shape of the humpback whale fin showing pectoral saw-tooth form. This zigzag structure will have counter-rotating vortex, rotating eddy currents will inject momentum, water adsorbed from the upper surface of the fins instead of bifurcation to both sides. Goshawk can fly with high speed above 80km/h and low noise. The quickly concealed flight make it become hunting experts.