Question

The Brayton cycle is an idealization of a set of thermodynamic processes used in gas turbine engines and consists in an adiabatic compression from p1 to p2, followed by an isobaric expansion an adiabatic expansion and a final isobaric compression. What is the thermal efficiency of such cycle.

Answer 1

The thermal efficiency of the Brayton cycle can be calculated using the formula:

η = 1 - (1 / r^(γ-1))

Where:
η = Thermal efficiency
r = Pressure ratio (p2/p1)
γ = Specific heat ratio (cp/cv) for the working fluid

In the Brayton cycle, the compression and expansion processes are adiabatic, so the specific heat ratio γ remains constant.

Therefore, the thermal efficiency of the Brayton cycle is solely dependent on the pressure ratio (r). The higher the pressure ratio, the higher the thermal efficiency of the cycle.

It is important to note that this calculation is an idealization and does not take into account real-world losses and efficiencies in actual gas turbine engines.