In a ducted fan turbine engine, how are the fan airflow and core airflow discharged?

In a ducted fan turbine engine, how are the fan airflow and core airflow discharged?

• A. They exit through separate nozzles without mixing.
• B. The fan flow bypasses the core entirely.
• C. They mix and exit through a common exhaust nozzle.
• D. The exhaust from the core flows through a bypass duct.

Answer: (C)

In a ducted fan turbofan, air entering the engine is split into bypass (fan) air and core air that goes through the combustor. In many designs those two streams are brought together before leaving the engine, mixing in a mixer or a common exhaust nozzle so they exit as one jet. This mixing lowers the overall jet velocity, helps reduce noise, and improves propulsion efficiency compared to having two separate nozzles. While some engines can exhaust through separate nozzles (unmixed), the typical arrangement for a ducted fan with a mixer is a single common exhaust nozzle.

In a ducted fan turbofan, air entering the engine is split into bypass (fan) air and core air that goes through the combustor. In many designs those two streams are brought together before leaving the engine, mixing in a mixer or a common exhaust nozzle so they exit as one jet. This mixing lowers the overall jet velocity, helps reduce noise, and improves propulsion efficiency compared to having two separate nozzles. While some engines can exhaust through separate nozzles (unmixed), the typical arrangement for a ducted fan with a mixer is a single common exhaust nozzle.