Rotordynamic characteristics of rotating labyrinth gas turbine seal with centrifugal growth

• Published in: Tribology international Vol. 97; pp. 349 - 359
• Main Authors: Subramanian, Sivakumar, Sekhar, A.S., Prasad, B.V.S.S.S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-05-2016
• Subjects: Computation; Deformation/centrifugal growth; Eccentricity; Gas turbine; Gas turbines; Labyrinth; Labyrinth seal; Mathematical models; Numerical analysis; Rotating; Rotational; Seals; Numerical analysis; Gas turbine; Deformation/centrifugal growth; Labyrinth seal
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2016.01.003

The rotordynamic characteristics of gas turbine seals have been investigated in numerous previous studies. However, the effects of centrifugal growth were often ignored; and no extensive studies have been reported. To this end, the present work examines numerically the influence of centrifugal growth on the rotordynamic characteristics of a typical rotating labyrinth gas turbine seal. A computational framework developed based on combined 3D FE/CFD methodology along with an appropriate rotordynamic model has been employed. For a given seal clearance and eccentricity, various flow and operating conditions are investigated covering a range of pressure ratios and rotational speeds. A substantial variation in both the cross-coupled stiffness and direct damping is noticed and the influence increases with rotational speed. The stability characteristics reveal that centrifugal growth of the seal has a detrimental effect at relatively low pressure ratio and high rotational speed combinations. The computational approach is validated against a typical labyrinth seal results reported in the literature.
•Computational framework developed for assessing gas turbine seal rotordynamics.•The 3D FE/CFD based methodology accounts for centrifugal growth of rotor/seal.•Centrifugal growth influences on seal rotordynamics is reported first time.•Seal stability analysis stresses significance of considering centrifugal growth.