Brayton cycle

The Brayton cycle is a thermodynamic cycle that describes the workings of a constant pressure heat engine. Gas turbine engines and airbreathing jet engines use the Brayton cycle. Although the Brayton cycle is usually run as an open system (and indeed must be run as such if internal combustion is used), it is conventionally assumed for the purposes of thermodynamic analysis that the exhaust gases are reused in the intake, enabling analysis as a closed system

A Brayton-type engine consists of three components:

1. a compressor
2. a mixing chamber
3. an expander 

The term Brayton cycle has more recently been given to the gas turbine engine. This also has three components:

1. a gas compressor
2. a burner (or combustion chamber)
3. an expansion turbine

Ideal Brayton cycle:

1. isentropic process - ambient air is drawn into the compressor, where it is pressurized.
2. isobaric process - the compressed air then runs through a combustion chamber, where fuel is burned, heating that air—a constant-pressure process, since the chamber is open to flow in and out.
3. isentropic process - the heated, pressurized air then gives up its energy, expanding through a turbine (or series of turbines). Some of the work extracted by the turbine is used to drive the compressor.
4. isobaric process - heat rejection (in the atmosphere).

Actual Brayton cycle:

1. adiabatic process - compression.
2. isobaric process - heat addition.
3. adiabatic process - expansion.
4. isobaric process - heat rejection.

Idealized Brayton cycle