Abstract:
Objective To analyze the noise in the air outlet of wind driven sprayer, explore the appropriate noise reduction methods and improve the noise reduction effect.
Method This paper analyzed the noise frequency spectrum in the air outlet of the wind driven sprayer, adopted the narrow-band active noise reduction method to reduce the noise of fan outlet, analyzed three common noise reduction algorithms, comparatively considered the convergence speed and noise reduction performance of three algorithms, and selected the NLMS algorithm as the core algorithm. In order to improve the frequency disturbance caused by non acoustic sensors in the narrow-band active noise reduction system, genetic algorithm was introduced to optimize the initial frequency calculated by the acquisition parameters of the rotator. The fan noise was taken as the input signal, and five frequency channels (197, 394, 591, 788 and 985 Hz) were used for narrow-band active noise reduction simulation.
Result The noise of the wind driven sprayer was mainly rotating noise caused by fan blade rotation. The simulation results showed that the system performance was improved after 33 iterations of the genetic algorithm. When the NLMS algorithm was iterated 10 000 times, the system converged, and the amplitudes of the five frequency channels were reduced by 0.192, 0.041, 0.024, 0.018 and 0.210 mm respectively, and the overall noise reduction effect was about 14 dB.
Conclusion The NLMS algorithm has better reduction effect on the noise of wind driven sprayer. Genetic algorithm can effectively improve the frequency disturbance caused by non acoustic sensors. This study provides a reference for active noise reduction methods of wind driven sprayers.
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