Which two methods of heat transfer are primarily utilized in boilers?

In boilers, the primary methods of heat transfer utilized are conduction and convection.

Conduction is the process of heat transfer through a solid material. In a boiler, this occurs as heat is conducted through the walls of the boiler tubes, which contain the water or steam. The hot gases from combustion transfer their heat to the boiler tubes by directly contacting them, facilitating efficient heating of the water or steam inside.

Convection, on the other hand, involves the transfer of heat through fluids (liquids and gases) due to the movement of the fluid itself. In boilers, the heated water or steam rises due to being less dense than the cooler water. This movement sets up a current within the boiler, ensuring that heat is evenly distributed throughout the fluid, maximizing the efficiency of the heating process.

Together, conduction and convection enable effective heat transfer and are crucial for the operation of boilers in providing steam for power generation or heating purposes.