How does a gas turbine operate as part of an open-cycle engine?

In an open-cycle gas-turbine engine, the process follows a continuous flow of air taken from the atmosphere. The operation involves several key stages:

• Compression: Atmospheric air is drawn in and compressed by a centrifugal or axial-flow compressor.
• Combustion: The compressed air enters a combustion chamber where fuel is added and burned at essentially constant pressure. To maintain safe operating temperatures for the turbine, additional compressed air is bypassed around the burning section and mixed with the hot combustion gases.
• Expansion: The hot, high-pressure gases expand through the turbine. In a system designed for shaft power, the gases expand to atmospheric pressure. Most of the turbine's work is consumed by the compressor, while the remainder provides useful power for a generator or pump.
• Thrust Generation: In a jet engine, the turbine provides only enough power to drive the compressor and auxiliary systems. The remaining gas stream, at intermediate pressure, is exhausted through a nozzle to produce thrust.1

This cycle is fundamentally based on the Brayton cycle, and its efficiency relies heavily on the performance of the compressor and turbine components.12