Where is the highest velocity found in a gas turbine engine?

• A. Exhaust area nozzle
• B. Intake compressor inlet
• C. Combustion chamber
• D. Turbine exit

Answer: (A)

The highest velocity is reached as the hot gases exit through the exhaust nozzle. In a gas turbine engine, energy added in the combustor raises the gas temperature and pressure, and the turbine later extracts some energy to drive the compressor. That means velocity inside the combustor and just after the turbine is not at its maximum. The intake/compressor inlet has flow entering the engine but isn’t arranged to accelerate to the engine’s highest speeds. The nozzle, however, is designed to convert most of the remaining pressure and internal energy into kinetic energy, accelerating the gas to the greatest speed as it leaves the engine. If the exhaust nozzle is optimized (often a convergent or convergent-divergent design), it drives the gas to the highest velocity, producing thrust.