关键词: 高压涡轮;叶尖间隙预估;主动间隙控制;涡轮性能退化;热变形

Abstract: For a certain type of high pressure turbine with active clearance control， a tip clearance estimation model considering engine degradation is established. The effects of turbine front gas temperature and creep deformation on tip clearance during long-term use and performance degradation of the engine are mainly studied. In the research， the introduction method of performance degradation of engine in gap prediction is analyzed firstly， and the corresponding gap estimation process is established. Subsequently， using the typical working history of an engine as the object， the variation of turbine tip clearance scale in the two conditions of traditional gap control scheme and scheme considering the performance degradation of engine are compared. The optimization of the gap control strategy is carried out accordingly. The study shows that the degradation of engine performance results in the increasing of turbine inlet gas temperature， which increases the thermal deformation of the casing， disc， and blade， especially for the casing. The elongation of the casing reaches 6.914 mm and increases 17% compared with the pre-degraded values. The blade and the disc are also affected by the creep deformation and affects the tip clearance value. Results predict that utilizing the optimized active clearance control scheme， the tip clearance value can be controlled within a reasonable range in various working conditions. Particularly in the high temperature takeoff phase， the value is 53% higher than that in the degraded state. It effectively avoids the occurrence of faults such as severe rubbing of the blades.

Key words: High pressure turbine;Tip clearance prediction;Active clearance control;Turbine performance degradation;Thermal deformation