How does reheating increase the output of a gas-turbine engine?

Reheating increases the output of a gas-turbine engine by adding energy to the working fluid after it has undergone partial expansion through a high-pressure turbine.1

In this process, the gas is directed into a second set of combustion chambers where it is reheated before being fed into a low-pressure turbine for final expansion. By increasing the temperature of the gas before it enters the low-pressure stage, the engine is able to generate more work during the subsequent expansion phase. This method is primarily utilized in stationary gas turbines, as the additional equipment required for reheating is generally impractical for the weight and size constraints of aircraft engines.1