Leakage and rotordynamic characteristics of labyrinth seal and hole-pattern damping seal with special-shaped 3D cavity

Purpose - The purpose of this paper is to enhance sealing and rotordynamic performance of hole-pattern damping seal (HPDS) and labyrinth seal (LS) by structural innovation and geometrical optimization of special-shaped hole or annular-groove cavity. Design/methodology/approach - The unsteady flow was transformed into steady one using moving reference frame method. The full period numerical models of LS and HPDS were established. The influence of special-shaped hole or annular-groove cavity at axial inclined angle on leakage rate and rotordynamic coefficient of these two seals at different whirl angular speed were investigated. Findings - The results show that dynamic characteristics of straight-tooth LS are better than that of slanted-tooth LS. Compared to typical straight-hole damping seal, HPDS with windward oblique-hole when axial inclined angle ranges from 50 to 60 degrees has superiority in both leakage and rotordynamic characteristics by considering smaller cross-coupled stiffness coefficient and whirl frequency ratio, larger direct damping coefficient and effective damping coefficient. Originality/value - A novel HPDS with special-shaped three-dimensional hole cavity was proposed to enhance leakage and rotordynamic performance. The optimized geometrical structures of HPDS for excellent sealing and rotordynamic characteristics were obtained. Peer review - The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0262/