Static Characteristics of Finger Seal considering Contact between Fingers and Rotor

Abstract

Finger seals are a new type of seal with good sealing performance and long service life. The noncontacting feature relies on the gas film force. However, when the seal works in an unsuitable environment or its design parameters are not reasonable, the lifting pad may not be able to generate sufficient air film force. This causes contact between the fingers and the rotor, resulting in a reduced service life of the seal. In view of this situation, this paper proposes a method that can quickly determine whether there is enough gas film force to lift the sealing finger at the design stage. The aeroelastic coupling characteristics of the noncontacting finger seal are studied in conditions where contact exists between the fingers and the rotor. The influences of various environmental and key structural parameters on the number of contact fingers, leakage, bearing force, and friction moment are studied. The results show that the pressure difference, eccentricity, and key design parameters have important effects on the number of contact fingers. The effect of rotation speed is relatively small. This paper provides a time-efficient tool for the design of noncontacting finger seals, which can quickly predict the performance of the sealing system.