What happens during the combustion section of a gas turbine cycle?

• A. Air is compressed to higher pressure with no heat addition.
• B. Exhaust gases cool the turbine.
• C. The rotor is rotated by external power.
• D. Fuel is burned to raise the temperature of the air.

Answer: (D)

The combustion section adds heat to the flow by burning fuel with the compressed air, raising its temperature and energy before it enters the turbine. This high-temperature gas provides the energy needed for the turbine to expand and produce shaft power.

In other words, fuel is burned to increase the air’s temperature from the compressor stage, not just compress it or cool anything. The turbine is driven by these hot gases, not by external power, and cooling the turbine with exhaust gases isn’t the function of the combustion chamber.