What is the primary purpose of the exhaust cone in a turbofan or turbine engine?

• A. To start ignition
• B. To reduce noise only
• C. To cool the exhaust
• D. Eliminate turbulence and maximize exhaust velocity

Answer: (D)

The exhaust cone is there to streamline and guide the hot gases as they leave the engine, reducing flow disturbances right at the outlet. By shaping the flow and keeping it aligned with the engine axis, it minimizes turbulence and flow separation, which would otherwise sap velocity and create losses. With a smoother, steadier exit, the exhaust velocity is maximized, boosting the momentum of the jet and, in turn, the engine thrust. Noise reduction and some minor turbulence control can occur as side effects, but the primary role is to eliminate flow irregularities and push the exhaust outlet to higher velocity.