Abstract A finger seal is a flexible and dynamic contact seal, and many researches and experiments have proved its application potential in aviation engines, gas turbines, and other equipment. However, the contradiction between hysteresis leakage and wear life in the design and initial installation condition of finger seals seriously affects the integrated performance design effect. A variable stiffness finger seal is investigated in the present study to resolve the aforementioned problems, and the influence of initial installation condition is considered. First, a theoretical model of the finger seal is established to calculate the hysteresis characteristic and contact pressure between finger feet and rotor. The performances of the variable stiffness finger seal and traditional involute curved finger seal are compared to confirm the advantages of the variable stiffness finger seal. The results show that the initial conditions such as rotor structure and support bearing clearance have an important influence on the accuracy of finger sealing performance calculation. In addition, the variable stiffness structure improves the hysteresis characteristic of the finger seal with virtually no loss of wear life under low pressure differential and reduces the hysteresis rate by more than 50%. Under high pressure differential, the variable stiffness structure reduces the average contact pressure by more than 25%. Therefore, the leakage and wear performance of the finger seal are simultaneously improved by the variable stiffness structure. This characteristic does not change with an increase in rotor excitation. This indicates that the variable stiffness finger seal provides good synthetic performance and high dynamic adaptability to random operating conditions.

中文翻译：

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变刚度手指密封的理论与实验研究

摘要 指形密封件是一种柔性的动态接触密封件，许多研究和实验证明了其在航空发动机、燃气轮机等设备中的应用潜力。然而，指形密封件在设计和初始安装工况中滞后泄漏与磨损寿命之间的矛盾严重影响了综合性能设计效果。为了解决上述问题，本研究研究了一种变刚度手指密封，并考虑了初始安装条件的影响。首先，建立了手指密封的理论模型，计算了指脚与转子之间的滞后特性和接触压力。将变刚度指形密封件与传统渐开线弯曲指形密封件的性能进行比较，以证实变刚度指形密封件的优点。结果表明，转子结构和支撑轴承间隙等初始条件对手指密封性能计算的精度有重要影响。此外，可变刚度结构改善了指状密封件的滞后特性，在低压差下几乎不会损失磨损寿命，并将滞后率降低 50% 以上。在高压差下，变刚度结构使平均接触压力降低25%以上。因此，变刚度结构同时提高了手指密封件的泄漏和磨损性能。该特性不会随着转子励磁的增加而改变。这表明可变刚度指形密封件提供了良好的合成性能和对随机操作条件的高动态适应性。