While fans are often used to cool people, they do not cool air (electric fans may warm it slightly due to the warming of their motors), but work by evaporative cooling of sweat and increased heat convection into the surrounding air, due to the airflow from the fans. sucking as in a vacuum cleaner), drying (usually in combination with a heat source) and providing draft for a fire. Typical applications include climate control and personal thermal comfort (e.g., an electric table or floor fan), vehicle engine cooling systems (e.g., in front of a radiator), machinery cooling systems (e.g., inside computers and audio power amplifiers), ventilation, fume extraction, winnowing (e.g., separating chaff of cereal grains), removing dust (e.g. A fan blade will often rotate when exposed to an air-fluid stream, and devices that take advantage of this, such as anemometers and wind turbines, often have designs similar to that of a fan.įurther information: centrifugal compressor Fans produce air flows with high volume and low pressure (although higher than ambient pressure), as opposed to compressors which produce high pressures at a comparatively low volume. Mechanically, a fan can be any revolving vane, or vanes used for producing currents of air. Most fans are powered by electric motors, but other sources of power may be used, including hydraulic motors, handcranks, and internal combustion engines. This may direct the airflow, or increase safety by preventing objects from contacting the fan blades. Usually, it is contained within some form of housing, or case. The rotating assembly of blades and hub is known as an impeller, rotor, or runner.
A fan consists of a rotating arrangement of vanes or blades, which act on the air. Fans are used to force air into low and high bypass jet engines, seen here on a Boeing 777.Ī fan is a powered machine used to create a flow of air.
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