Research on the aerodynamic characteristics of multifunction straw stalk crusher with the kneading condition

There are problems of significant vibration and high noise when multifunction straw stalk crushers are operating. Aerodynamic noise is the main component of noise of multifunction straw stalk crushers. To explore the effects of structural configuration and operational parameters on the aerodynamic noise of multifunction straw stalk crushers. The CFD-DEM coupling method is used to numerically simulate the air-straw coupled flow field inside the multifunction straw stalk crusher to obtain the aerodynamic characteristics. On this basis, the aerodynamic noise of the multifunction straw stalk crusher is predicted, and its influencing factors are analyzed. The results show that compared with the idle condition, the resistance coefficient of the discharge pipe under the load condition is increased by 69.81%, and the eddy current viscosity gradient of the discharge pipe (2.33e −4 Pa·s) is significantly higher than that of the feed tank (4.55e −5 Pa·s), resulting in a significant increase in noise at the outlet. Compared with the idle condition, the total sound pressure level of the aerodynamic noise at the outlet under the load condition rises from 91.08 dB(A) to 106.29 dB(A), and the total sound pressure level of the aerodynamic noise at the inlet under the load condition rises from 84.75 dB(A) to 95.27 dB(A). The rotor speed, the number of hammers, the discharge angle, the length of the feed tank, and the number of cutting knives are the primary factors that significantly affect the aerodynamic noise of the straw stalk crusher. The research can provide a reference for the low-noise optimization design of straw stalk crushers.