Systematic parametric studies were performed to better understand seal-inlet rotordynamics.
A CFD-perturbation model was employed to compute the seal-inlet flow
disturbance quantities. Seal inlet disturbance boundary condition correlations were
proposed from the computed seal-inlet quantities using the important parameters. It
was found that the cosine component of the seal-inlet swirl velocity disturbance W1C
has a substantial impact on the cross-coupled stiffness, and that the correlations for
W1C and W1S should be used to replace the historical guess that seal inlet W1C = 0
and W1S = 0. Also, an extremely precise relationship was found between the swirl
disturbance W1C and the seal-inlet swirl velocity (ÃÂRsh â ïW0). Thus, the number
of experiments or computer runs needed to determine the effect of spin speed, shaft
radius and/or inlet swirl velocity on the cross-coupled stiffness is greatly reduced by
plotting the simplified relationship of the cross-coupled stiffness against the swirl slip
velocity. The benefits of using the new seal-inlet boundary condition correlations
were assessed by implementing them into a CFD-perturbation model. Consistently
improved agreement with measurements was obtained for both liquid annular seals
and gas labyrinth seals.
Further, the well-established CFD-perturbation model with new boundary condition
correlations was employed to investigate the rotordynamics of two off-design situations. The first case considered the influence of labyrinth seal teeth damage on
the performance and the rotordynamic characteristics of impeller eye seals in centrifugal
compressors. The second case considered the influence of rotor-axial-shifting on
rotordynamic forces for high-low labyrinth seals in steam turbines during the start-up
and shut-down process. The results should provide useful information for labyrinth
seal design and fault diagnosis of stability problems in turbines and compressors.
| Identifer | oai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4971 |
| Date | 25 April 2007 |
| Creators | Xi, Jinxiang |
| Contributors | Rhode, David L. |
| Publisher | Texas A&M University |
| Source Sets | Texas A and M University |
| Language | en_US |
| Detected Language | English |
| Type | Book, Thesis, Electronic Dissertation, text |
| Format | 993662 bytes, electronic, application/pdf, born digital |
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