From which section of a turbine engine does the bleed air that cools bearings come?

The bleed air that is used to cool bearings in a turbine engine originates from the compressor section. This section is responsible for compressing incoming air before it enters the combustion chamber where fuel is mixed and ignited. During this process, some of the compressed air, referred to as bleed air, can be diverted for various uses, including bearing cooling.

Using bleed air for cooling is advantageous because it is already at a high pressure and relatively low temperature compared to the hot gases in the combustion and exhaust sections. This helps to keep the bearings operating at optimal temperatures, preventing overheating and prolonging their life. The use of bleed air enhances the overall efficiency of the engine by managing thermal loads effectively.

In contrast, bleed air drawn from the exhaust would not be suitable for cooling bearings, as it would be too hot and could damage the engine components. Similarly, air from the combustion section is also not used for bearing cooling due to its extremely high temperatures. The fuel system section does not produce or manage bleed air; its function is solely related to delivering fuel to the combustion chamber. Thus, the compressor section is the correct answer.