The air-standard Brayton cycle is a theoretical cycle for gas turbines. This cycle consists of two reversible adiabatic or isentropic processes and two constant pressure processes.
This thermodynamic cycle is represented on p-V and T-s coordinates, is similar to diesel cycle in compression and heat addition. The isentropic expansion of diesel cycle is further extended followed by constant pressure heat rejection.
1-2: Isentropic process
2-3: Isobaric process
3-4: Isentropic Process
4-1: Isobaric process
Thermal Efficiency can be calculated by the formula
Where ‘k’ is the specific heat ratio Cp/Cv.