Why does raising the turbine-inlet temperature increase the efficiency of a gas-turbine engine?

Raising the turbine-inlet temperature increases the efficiency and power output of a gas-turbine engine by allowing the working fluid to expand more effectively through the turbine.12

In the Brayton cycle, the engine compresses air, adds heat to increase its energy, and then expands the resulting hot gas through a turbine to produce mechanical work. By increasing the temperature at the turbine inlet, the gas gains more energy, which enhances the turbine's ability to extract work from the expanding fluid.23

While higher temperatures improve performance, they also present engineering challenges. Turbine blades are subject to extreme centrifugal stresses and high speeds, and materials naturally lose strength at elevated temperatures. Consequently, modern engines operating at temperatures above 1,100° C—and sometimes exceeding 1,370° C—require specialized blade cooling techniques to maintain structural integrity. For every maximum turbine-inlet temperature, engineers must also determine an optimum pressure ratio to balance these thermal and mechanical demands.1