Convection heat transfer

Convection heat transfer (Latin convectio - bringing, delivery) is a heat transfer process in which the movement of heat occurs along with the macroscopic movement of the medium.

Convection heat transfer occurs due to the movement of liquid or gas molecules. When a liquid or gas is heated, its molecules begin to move more intensely and collide with each other, transferring kinetic energy to each other. As a result, more heated and mobile molecules move to the interface, transferring their energy to less heated ones.

Convection heat exchange can be forced, when the movement of the medium occurs under the influence of external forces (for example, a pump), and free (natural), when the movement is caused by the difference in the densities of heated and cooled masses in the field of gravity.

Examples of convection heat transfer are heating a room using radiators, cooling the processor in a computer using a fan, or heating water in a pan on the stove. Convection heat transfer plays an important role in many technical devices and natural processes.

**Convection heat transfer** is the process of transferring thermal energy from one surface to another through air currents. It occurs when two bodies of different temperatures come into contact and consists in the fact that hotter gases or vapors in contact with colder surfaces or substances transfer their energy to them, causing their temperature to increase.

An example of convective heat transfer is a kettle sitting on a fire. The heated water is heated due to the thermal conductivity of the metal and warm steam enters the air through it. Convection can also occur without contact of bodies, when warm layers of gas or vapor rise and are carried upward by a flow of cold gases. This is called free convection.

Heat transfer by convection