Question

Which of the following process ideally represents combustion in gas turbine engines?

• A. Adiabatic
• B. Isentropic
• C. Isobaric
• D. Isochoric

Hint:

Brayton cycle assumes isobaric heat addition and rejection.

Answer 1

The Correct Option is C

In gas turbine engines, the combustion process is ideally represented as an isobaric process. Let's explore why that is the case.

A gas turbine engine consists of several stages: compression, combustion, and expansion. The combustion process is a key stage where fuel is burned to add energy to the system. In an isobaric process:

• The pressure remains constant while the volume changes.
• The heat added to the system contributes to an increase in the internal energy, raising the temperature and volume at constant pressure.

Other processes mentioned:

• Adiabatic: No heat exchange with the surroundings; it does not represent the combustion phase in gas turbines where heat is added.
• Isentropic: Both adiabatic and reversible; ideal for compression or expansion but not applicable during combustion where heat is added.
• Isochoric: Constant volume process; not feasible in gas turbines as the volume changes in the combustion chamber.

Due to the characteristics of combustion in gas turbines, the process occurs at constant pressure, making it the isobaric process.