In a turbofan engine, how is cooling primarily achieved?

In a turbofan engine, how is cooling primarily achieved?

• A. The engine is cooled only by coolant in the core.
• B. A large portion of the air flows over the outside of the engine, helping to cool the various sections.
• C. Cooling is not required for turbofan engines.
• D. The exhaust gas cools the engine.

Answer: (B)

Cooling in a turbofan is achieved mainly by the large flow of air that passes around the outside of the engine. This bypass air surrounds the core and cools the nacelle, external surfaces, and accessories through convection, acting as a heat sink for the engine structure. The core itself is cooled by air taken from the compressor (bleed air) and by lubrication/oil cooling—not by some liquid coolant circulating through the core. Exhaust gas is hot and does not provide cooling for the engine. So the primary cooling path is the bypass air flowing around the outside of the engine.

Cooling in a turbofan is achieved mainly by the large flow of air that passes around the outside of the engine. This bypass air surrounds the core and cools the nacelle, external surfaces, and accessories through convection, acting as a heat sink for the engine structure. The core itself is cooled by air taken from the compressor (bleed air) and by lubrication/oil cooling—not by some liquid coolant circulating through the core. Exhaust gas is hot and does not provide cooling for the engine. So the primary cooling path is the bypass air flowing around the outside of the engine.