What is the main purpose of fuel combustion in a gas turbine engine?

• A. To raise gas velocity
• B. To heat air for icing protection
• C. To produce shaft power directly
• D. To reduce exhaust temperature

Answer: (A)

Fuel combustion in a gas turbine adds heat to the compressed air, raising its temperature and energy content. That energy is what allows the turbine to extract work as the hot gases expand, driving the turbine and, in turn, turning the compressor and providing shaft power. Raising the gas velocity is a byproduct of this energy addition, but not the primary aim of combustion. The main purpose is to supply energy to the gas stream so the turbine can convert it into mechanical power. Heating air for icing protection comes from separate systems, and reducing exhaust temperature would require removing heat, not adding it. So the essential purpose of combustion is to furnish energy to the gas flow to drive the turbine and generate shaft power.