A fan gives off forced convection heat transfer.
Forced convection heat transfer occurs when a fluid, in this case, air, is forced to move over a surface by an external means, such as a fan. As the fan blades rotate, they push the air, creating a flow of air or fluid across the surface it is directed towards.
The movement of air by the fan increases the rate of heat transfer between the surface and the air. The moving air carries away heat from the surface, which can help cool down the surface or dissipate heat from a hot object. This is why fans are commonly used in various applications to enhance cooling, such as cooling electronic devices, circulating air in a room to reduce temperature, or aiding in the cooling of machinery and engines.
In summary, a fan provides forced convection heat transfer by moving air over a surface, which increases the rate of heat transfer between the surface and the surrounding air.