Brayton or Joule Cycle

The Brayton or the Joule Cycle is the ideal cycle on which a closed cycle gas turbine power plant functions. The figures shown below gives the cycle, on T – s diagram, on which the plant operates.

                                 Figure: Closed Cycle Gas Turbine Power Plant

                                                      Figure: Brayton Cycle

This is the Joule or Brayton Cycle. The states of air marked in the schematic diagram and cycle diagrams are well-matched. The Brayton Cycle, as shown in figure above, consists of the following procedure: 1 – 2, reversible adiabatic compression; 2 – 3, reversible constant pressure heating; 3 – 4, reversible adiabatic expansion and 4 – 1 reversible constant pressure cooling. The heat transfer to the system is QH and the total work output of the system is (W_T – W_C).