Question 97Gas Turbine - 1st Asst/Chief

The correct answer is D) Bleed air. The turbine blade in the illustration GT-0029 is likely part of a gas turbine engine, which is commonly used in aircraft and ships. To prevent overheating of the turbine blade, bleed air from the engine's compressor section is circulated through the shaped internal passages within the blade. This bleed air acts as a coolant, absorbing heat from the blade and preventing it from overheating during operation. The other options, such as cooling water (A) or cooling oil (B), are not typically used for turbine blade cooling in this type of application. External compressed air (C) could also be used, but bleed air from the engine's own compressor section is the more common and efficient cooling method.