摘要：The technical approach "use – parts' change - engine performance change" has been adopted to study and analyse the gas unit parts' performance changes of an engine after a long time operation. The mechanism of performance decline of the turbine is analysed based on the numerical simulation, the impact of components' performance decline on overall engine performance is studied and the correlation analysis is carried out. The results show that the change of turbine tip clearance, roughness increase and surface change will lead to the enhancement of secondary flow and the increase of influence area, and the turbulence effect is strengthened, resulting in the decrease of turbine circulation capacity and efficiency. The booster ratio of high pressure compressor, the flow capacity of high pressure and low pressure turbines, the flow capacity and efficiency of fan are the major component parameters causing the overall engine performance's degradation. And it also provides theoretical basis for the prevention of engine performance's degradation and online washing of parts and the whole machine.
