11-62 Type centrifugal fan With large air volume, low noise and smooth operation, the centrifugal fan is the preferred product for hotels, restaurants and smoke exhaust ventilation. According to the principle of converting kinetic energy into potential energy, the centrifugal fan uses high-speed rotating impeller to accelerate the gas, then decelerate and change the flow direction to convert kinetic energy into potential energy (pressure). In a single-stage centrifugal fan, the gas enters the impeller from the axial direction, changes to the radial direction when it flows through the impeller, and then enters the diffuser. In the diffuser, the gas changes the flow direction and the increase of pipe section area slows down the gas flow, which converts kinetic energy into pressure energy. The pressure increase mainly occurs in the impeller, followed by the diffusion process. In a multistage centrifugal fan, a reflux device is used to make the air flow enter the next impeller to generate higher pressure.

The working principle of the centrifugal fan is basically the same as that of the turbine compressor. Because the gas flow rate is low and the pressure changes little, it is generally unnecessary to consider the change of the gas specific volume, that is, treat the gas as an incompressible fluid.

The centrifugal fan can be made into two types: right rotation and left rotation. Facing from one side of the motor: the impeller rotates clockwise, which is called the right rotating fan; The impeller rotates counterclockwise, which is called left rotating fan.