Why are bleed valves fitted to gas turbine engines?

Bleed valves are an essential component in gas turbine engines primarily for managing the airflow within the engine. Their main purpose is to provide the necessary bleed air for various systems that rely on this air to function properly. This includes the air conditioning system and ensuring proper cooling of engine components.

By allowing a portion of compressed air to be directed away from the compressor stages, bleed valves enable the extraction of air that can be used for cabin pressurization and cooling systems, playing a crucial role in the overall thermal management of the aircraft. This operation contributes significantly to passenger comfort and operational efficiency.

While bleed valves might have indirect benefits such as assisting in overall engine performance or contributing to thrust management, their primary and most critical role is related to air conditioning and cooling. This makes them vital for maintaining optimal conditions both within the engine and for the passengers.