The working principle of the centrifugal fan is basically the same as that of the turbo compressor, except that the gas flow rate is low and the pressure changes little. Generally, there is no need to consider the change of the gas specific volume, that is, the gas is treated as an incompressible fluid. Centrifugal fans can be made into two types, right-handed and left-handed. When viewed from the side of the motor, the impeller rotates clockwise, which is called right-rotating fan, and counterclockwise, which is called left-handed.

Centrifugal fan is a machine that relies on input mechanical energy to increase gas pressure and discharge gas. It is a driven fluid machine. Centrifugal fans are widely used for ventilation, dust exhaust and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings; ventilation and induced air for boilers and industrial furnaces; cooling and cooling in air conditioning equipment and household appliances Ventilation; drying and selective delivery of grains; air source of wind tunnel and inflation and propulsion of hovercraft.