What is an example of forced convection?
Forced convection: When external sources such as fans and pumps are used for creating induced convection, it is known as forced convection. Examples of forced convection are using water heaters or geysers for instant heating of water and using a fan on a hot summer day.
Why is forced convection important?
Forced convection creates a more uniform and therefore comfortable temperature throughout the entire home. This reduces cold spots in the house, reducing the need to crank the thermostat to a higher temperature, or putting on sweaters.
How does natural convection occur?
Natural convection arises from temperature differences among air parcels, or heat transfer at surfaces (i.e. surface-to-air temperature difference). In the absence of forced convection, natural convection becomes the only means of air mixing inside enclosed spaces.
Where is forced convection used?
heat exchangers
It is used in heating and air conditioning systems, electronics cooling, and in numerous other technologies. Forced convection is used in designing heat exchangers, in which one fluid stream is used to heat or cool another fluid stream. Figure 12.5 illustrates a flat plate being cooled by forced convection from a fan.
Is wind forced convection?
The convection caused by winds is natural convection for the earth, but it is forced convection for bodies subjected to the winds since for the body it makes no difference whether the air motion is caused by a fan or by the winds.
How do fans use convection?
Very simply put, a convection oven has a fan and exhaust system that a regular oven does not. The fan and exhaust help blow hot oven air over and around the food, then vent it back out. As a result, this hot air surrounds the food so that it cooks evenly and more quickly.
Can convection take place without gravity?
Because gravity is necessary for density differences to arise, neither buoyancy nor convection occur in a zero-gravity environment such as space.
What is the difference between forced and natural convection?
In natural convection, any fluid motion is caused by natural means such as the buoyancy effect, i.e. the rise of warmer fluid and fall the cooler fluid. Whereas in forced convection, the fluid is forced to flow over a surface or in a tube by external means such as a pump or fan.
What are the three main sources of convection?
The primary sources of thermal energy for mantle convection are three: (1) internal heating due to the decay of the radioactive isotopes of uranium, thorium, and potassium; (2) the long-term secular cooling of the earth; and (3) heat from the core.
What type of convection produces winds?
Small-scale convection currents arise from uneven heating on a smaller scale. This kind of heating occurs along a coast and in the mountains. Small-scale convection currents cause local winds. Local winds blow over a much smaller area and change direction and speed over a shorter period of time than global winds.