The centrifugal fan is a machine that uses mechanical energy to increase the gas pressure and then transports the gas out. It is one of the four major components in the dust removal and ventilation system.
Centrifugal fan is a kind of impeller machinery, which is widely used in various fields such as energy, environment, aviation, etc. It is one of the main energy-consuming equipment in industrial and agricultural production. The centrifugal fan is one of the four major parts of the dust removal and ventilation system. It is a relatively precise operating machine. It relies on the rotation of the impeller to form a negative pressure inside the fan, sucks in external air and discharges the fan through the impeller channel and volute.
The centrifugal fan is mainly composed of casing, impeller, shaft, collector, exhaust port, bearing box, coupling, pulley and base.
Rotation noise is also called discrete frequency noise or pass frequency noise. When the fan rotates. At the exit of the blade channel on the rotating impeller, the airflow pressure and the airflow velocity along the circumferential direction have great changes. When the gap between the volute tongue and the edge of the blade outlet is small, periodic pressure and speed pulsations will appear when the rotating blade channel passes over the volute tongue. The noise generated by the pulsation is called rotational noise.
Vortex noise is also called turbulence noise or vortex noise. It is the broadband noise radiated by the interaction and coupling between the impeller blades and the gas during the rotation of the impeller, including incoming turbulence noise, turbulent boundary layer noise, and tail noise. Edge vortex shedding noise and blade tip vortex noise. The main reason for this is the detachment of the boundary layer near the exit of the blade, the detachment of the air flow when the air diffuses in the volute, the separation of the flow at the inlet of the blade, and the deterioration of the flow when it deviates from the best working conditions.
