From where is air usually taken for anti-icing in a gas turbine engine?

Air used for anti-icing in a gas turbine engine is typically taken from the compressor. This is because the compressor section of the engine is designed to compress ambient air, significantly increasing its pressure and temperature. By utilizing this compressed air for anti-icing purposes, the engine can effectively ensure that critical components, such as the leading edges of the blades, remain free of ice accumulation.

The compressor air is also relatively warm compared to ambient conditions, which helps to melt any ice that may form on surfaces exposed to cold air. Using the compressor for this purpose is also efficient, as it takes advantage of air that has already been processed for combustion, ensuring that the anti-icing system does not detract from engine performance.

In contrast, air sources such as the fuel system, combustion chamber, or turbine exhaust do not provide appropriate temperatures or pressures for effective anti-icing. Fuel system air could introduce contaminants, while air from the combustion chamber is too hot and could cause thermal damage. Likewise, turbine exhaust air is at a very low pressure after having passed through the turbines, making it ineffective for this specific function.