65.24 Turbine Engine Air Cooling and Sealing

65.24.2 Describe the requirement for cooling and sealing of turbine engine components.

Turbine engine components operate under extremely high temperatures, pressures, and rotational loads. Cooling and sealing are required to keep these components within safe operating limits and to maintain efficient engine operation.

Requirement for Cooling

The temperature of the gases leaving the combustion chamber may be higher than the turbine components could withstand without cooling.

Cooling is required to:

• prevent turbine blades, nozzle guide vanes, discs, and casings from overheating;

• prevent loss of material strength, turbine blade creep, distortion, cracking, and burning;

• protect bearings, shafts, and lubricating oil from excessive heat;

• maintain correct operating clearances between rotating and stationary components;

• extend component and engine life.

Requirement for Sealing

A turbine engine depends on controlled airflow and pressure differences between its various sections.

Sealing is required to: