A firetube boiler is one that has?

A firetube boiler is characterized by having water on the outside of the tubes and hot gas on the inside of the tubes. This design allows the hot combustion gases produced in the furnace to flow through the tubes, transferring heat to the water surrounding them. As the hot gases travel through the tubes, the heat is transferred to the water, converting it into steam or raising its temperature significantly.

The arrangement of the boiler's components facilitates efficient heat transfer from the combustion gases to the water. As the gases exit the tubes, they cool down significantly, while the water heats up, thereby creating steam or hot water as required for various applications. This configuration is fundamental in distinguishing firetube boilers from watertube boilers, where the flow dynamics and placement of water and gases are reversed.

Understanding the flow of hot gases and water in a firetube boiler is essential for recognizing its operational principles and efficiency in energy conversion. This knowledge is critical for anyone studying power engineering and working with different types of boilers.