Jet propulsion unit flow path: after passing through the gas turbine, where are the combustion products discharged?

Introduction / Context:
In turbojet and turbofan cores, air is compressed, mixed with fuel, burned, expanded through a turbine to drive the compressor, and finally expanded further to generate thrust. Understanding the sequence of components is foundational for propulsion studies.

Given Data / Assumptions:

• Standard jet propulsion unit (e.g., turbojet core).
• Open cycle exchanging mass with the surroundings.
• No afterburner considered for the basic path.

Concept / Approach:
After the gas turbine extracts shaft work to drive the compressor, the partially expanded, still-energetic exhaust gases are accelerated through the exhaust nozzle. The nozzle converts remaining thermal and pressure energy into a high-velocity jet, producing thrust by momentum change.

Step-by-Step Solution:
Compressor → Combustor → Turbine (to drive compressor).Turbine exit gases retain pressure and temperature.Gases pass into the exhaust (discharge) nozzle where pressure energy converts to kinetic energy.High-speed jet issues to the atmosphere, creating thrust.

Verification / Alternative check:
Thrust equation uses mass flow times jet velocity relative to flight speed; the exhaust nozzle is the component setting the jet velocity.

Why Other Options Are Wrong:

• Atmosphere (directly): gases first expand through the nozzle; the nozzle is the immediate component after the turbine.
• Vacuum chamber: not present in open-cycle aircraft engines.
• Back to compressor: would imply a closed cycle, not used in aircraft jet propulsion.
• Closed plenum: inconsistent with thrust generation.

Common Pitfalls:
Confusing “nozzle exit to atmosphere” with “discharged to atmosphere.” The immediate device is the nozzle, which shapes and accelerates the flow.

Final Answer:
Discharge (exhaust) nozzle