Rôle des matériaux dans la turbine à gaz

Part played by materials in gas turbine

Office National d’Etudes et de Recherches Aérospatiales

Abstract

It is well known that the actual gas-turbine cycle differs very much from the ideal Carnot cycle. However, it is easy to show that high temperatures increase the power per mass flow rate unit and diminish the consumption per power unit.

For fourty years, metallurgy has allowed a gain of about 600°C on the maximum temperatures of cycles. This gain comes from improvements in three domains : creep limits (270°C), cooling techniques (220°C), and material of the blade disks (110°C). With that 600 °C gain, roughly one half of the improvement (330 °C) of the gas turbine efficiency is due to metallurgy. The other half has to be attributed to the aerodynamicists, thermicists and technologists.

With an efficiency reaching now 40 % the gas-turbine compares with the best energy transformers (Diesel, steam-turbine). By complicating the cycle and extrapolating the materials performances, one can hope to reach a 55 % efficiency.