Abstract: With the development of refrigerator noise to ultra quiet level, higher requirements are put forward for pneumatic noise control. Taking the refrigerator fan of household refrigerator as the research object, the tail edge structures of different mixing forms are designed, and the noise reduction mechanism is studied by using acoustic analogy FW-H calculation method and experiments. The results show that both the acceleration channel and the bionic structure can improve the pressure gradient at the trailing edge of the blade and the vorticity of the blade and blade tip, so as to reduce the noise of the fan blade. For the prototype fan with 7 blades and a diameter of 41.8 mm, on the premise of ensuring performance, when the speed is constant at 1980 r/min, the maximum noise reduction of the acceleration channel blades can reach 1.7 dB(A), and the noise reduction effect is better than that of bionic blades. When the maximum pressure on the blade surface is extracted as the sound source, the calculation result of sound propagation will be inaccurate. This is because the location of the extracted sound source is contrary to the noise reduction design. Considering the limitations of the sound analogy calculation method, modifies the sound source surface extraction method, and carries out experimental verification to obtain better results.

Key words: Blade, Aerodynamic noise, Acoustic analogy, FW-H, Sound propagation