Forced Convection:

Forced convection is a mode of heat transfer in which a fluid is forced to flow over a surface or in a tube by external means such as a pump, fan or compressor. It is also known as forced flow convection.

Example:

Out of the given options, the example of forced convection is the flow of water in condenser tubes. The flow of water is forced by a pump to flow over the surface of the condenser tubes. The heat from the hot refrigerant gas is transferred to the water flowing over the surface of the tubes, and the water picks up the heat and carries it away. In this way, the heat is transferred from the refrigerant gas to the water through forced convection.

Explanation:

In the process of refrigeration, the refrigerant gas is compressed by a compressor, which increases its temperature. This hot compressed gas is then passed through a condenser where it is cooled down by transferring the heat to the water flowing over the surface of the tubes. The water is then cooled down by passing it through a cooling tower or some other means. The cooled refrigerant gas is then passed through an expansion valve where it is expanded and cooled down further. This cold refrigerant gas is then passed through an evaporator where it absorbs heat from the surrounding air or water and gets converted into a gas again. The cycle then repeats itself.

In the process of cooling the refrigerant gas in the condenser, forced convection plays a major role. The flow of water over the surface of the tubes is forced by a pump, which increases the rate of heat transfer from the refrigerant gas to the water. This results in faster cooling of the refrigerant gas and increases the efficiency of the refrigeration system.

Conclusion:

Forced convection is an important mode of heat transfer in various industrial processes such as refrigeration, air conditioning, heat exchangers, etc. It is also used in various applications such as cooling of electronic components, thermal management of power plants, etc.