When the main feed pump discharges feedwater toward the boiler, the feedwater is transported by what kind of heat transfer?

The correct answer highlights that the feedwater is transported to the boiler through forced convection. Forced convection occurs when a fluid is moved by an external mechanical force, such as a pump. In this case, the main feed pump actively pushes the feedwater through the piping system toward the boiler, which is an essential function in maintaining proper water levels and ensuring efficient heat exchange within the boiler.

Understanding forced convection is crucial because it allows for efficient heat transfer between the feedwater and the hot surfaces of the boiler. As the water is forced through the system, it absorbs heat from the combustion gases in the boiler, effectively converting the feedwater into steam.

In contrast, conduction refers to heat transfer through direct contact without the movement of the material, which is not applicable here as the fluid is actively being moved. Natural convection, on the other hand, occurs due to buoyancy forces from temperature differences within a fluid, which does not apply since the feedwater movement is not reliant on these factors but on the pump's mechanical action. Radiation involves heat transfer through electromagnetic waves and is not relevant in this context since it does not contribute to the mechanism by which the feedwater is transported.