Coupling Bionic Design and Numerical Simulation of the Wavy Leading-Edge and Seagull Airfoil of Axial Flow Blade for Air-conditioner

It is essential to maintain the aerodynamic performance of the air-conditioning system meanwhile reducing the noises (including aerodynamic, broadband, and discrete noises), determining the consumer's comfort level. In this work, depending on the coupling of the wavy leading-edge and the seagull airfoil, the aeroacoustics noise and aerodynamic performance of the impellers with the coupling bionic blade were investigated in detail. The results indicate the aerodynamic performance was improved by the coupling bionic optimization. Moreover, the total pressure efficiency (η) of the coupling bionic blade increases by 2.28% in comparison to the original blade. Furthermore, A smaller static differential pressure is observed between the suction and pressure sides, and vortices and backflows from the pressure side to the suction side are hampered, causing a reduction in turbulence noise. Additionally, the broadband noise of the coupling bionic blade decreases by 3.59 dB. Besides, the coupling bionic blade improves the directivity of the sound pressure level, especially in the middle-frequency and low-frequency region, resulting in a decrease of 7.9 dB for the aeroacoustics noise of the coupling bionic blade. What's more, the modal analysis demonstrates the security of the designed coupling bionic blade. In generally, this work provides some inspiration to design axial flow fans with excellent aerodynamic performance and low-noise characteristics.