Experimental Study on the Noise Reduction Effect of Bionic Sawtooth Blades
Improving the aerodynamic performance and noise level of an engine with bionic structure is a hot research topic in green aviation,and it has important engineering application value for controlling the aerodynamic noise of counter-rotating propellers.In this paper,the aerodynamic noise reduction characteristics of the bionic sawtooth structure on the rotary propeller are investigated through the aerodynamic noise test under the ground acoustic environment,and the aerodynamic performances of the sawtooth blade and the reference propeller in terms of tension and torque,as well as the directivity of the far-field noise are tested.The test results show that the designed sawtooth structure does not cause the loss of the aerodynamic performance of the reference propeller,and the noise reduction design can be carried out while maintaining the aerodynamic performance.The sawtooth structure does not change the noise directivity characteristics of the reference blade in the frequency range of 4000～12000Hz,and the maximum noise reduction is more than 5dB;there is no obvious noise reduction effect in the first-order pass-by frequency and second-order pass-by frequency of the measured rotational speed conditions.This further indicates that the sawtooth structure has a noise reduction effect on the broadband noise,but not on the discrete noise in the low-frequency band.
bionic typesawtooth structurecounter-rotating propelleraerodynamic noiseexperimental test
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