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 in ventilation, dust exhaust and cooling of factories, mines, tunnels, cooling towers, vehicles, ships and buildings; ventilation and induced air of 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, etc.