The Effects of Bleed on Acceleration Performance of Turbofan Engine

The acceleration performance of military turbofan engine is often limited by the surge margin of compressor and the working temperature of hot side components. However, the development level of thermostable materials is far from meeting the requirements of safe and stable operation of turbine blades of aeroengines. The method of cooling turbine blades by extracting air between compressor stages is often used to prevent the temperature in front of the turbine from exceeding the limit. During acceleration process, the compressor interstage bleed can increase the surge margin of the compressor. However, bleeding will cause flow loss. In order to improve the acceleration performance of the engine and reduce the energy loss caused by bleeding on the premise of ensuring the safe operation of the engine, taking the turbofan engine with six stages as the research object, the compressor interstage bleed model is established to study the influence of bleed positions and ratios on the acceleration performance. It is found that increasing the bleed air ratio can improve the acceleration performance within a reasonable range and the rear stage bleed can significantly improve the acceleration performance of turbofan engine.