Circumferentially-grooved seals are used in centrifugal pumps to reduce leakage flow. They can also have a significant impact on pump rotordynamic characteristics. Florjancic (1990) developed an analysis for leakage and rotordynamic coefficients, using a partition of the seal into three control volumes. This paper presents a new theory, based on an extension of Florjancic’s work (1990) for circumferentially-grooved liquid seals. The current theory differs from Florjancic’s analysis in the retention of transfer momentum terms and the introduction of diverging flow in the through-flow section within a seal groove. Validation of the new analysis is achieved through a comparison with existing experimental data taken from Kilgore (1988), and Florjancic (1990). Theoretical results are reasonable and consistent; i.e., a modification in the seal parameters induces a correct evolution of the rotordynamic coefficients. Direct and cross-coupled stiffness coefficients are slightly underpredicted, whereas the direct damping coefficient is underpredicted within 40 percent. Leakage flow predictions are very good.

Issue Section:
Research Papers
Topics:
Centrifugal pumps, Damping, Flow (Dynamics), Leakage, Leakage flows, Momentum, Pumps, Stiffness
1.
Black, H. F., and Cochrane, E. A., 1973, “Leakage and Hybrid Bearing Properties of Serrated Seals in Centrifugal Pumps,” Presented at the 6th International Conference on Fluid Sealing, Munich, Germany, G5-61-G5-70.
2.
Childs, D. W., 1993, Turhomachinery Rotordynamics: Phenomena, Modeling, and Analysis, Wiley Interscience, New York.
3.
Childs, D. W., 1988, “SSME Seal Test Program; Tests Results for Smooth, Hole-Pattern, and Helically-Grooved Stators,” Texas A&M University, Report No.: TRC-Seal-7-87, revised June 1988.
4.
Florjancic, S., 1990, “Annular Seals of High Energy Centrifugal Pumps: A New Theory and Full Scale Measurement of Rotordynamic Coefficients and Hydraulic Friction Factors,” Ph.D. dissertation, Swiss Federal Institute of Technology, Zu¨rich, Switzerland.
5.
Hirs, G., 1973, “A Bulk-Flow Theory for Turbulence in Lubricant Films,” ASME JOURNAL OF LUBRICATION TECHNOLOGY, Vol., Apr., pp. 137–146.
6.
Iwatsubo, T., and Sheng, B., 1990, “Evaluation of Dynamic Characteristics of Parallel Grooved Seals by Theory and Experiment,” Proceedings of the Third IFToMM International Conference on Rotordynamics, Lyon, France, pp. 313–318.
7.
Iwatsubo, T., Sheng, B., and Ono, M., 1990, “Experiment of Static and Dynamic Characteristics of Spiral Grooved Seals,” Rotordynamic Instability Problems in High-Performance Turbomachinery, NASA CP No. 3122, Proceedings of a Workshop held at Texas A&M University, pp. 223–234.
8.
Kilgore, J. J., 1988, “Rotordynamic Coefficients and Leakage Flow for Parallel-Grooved Liquid-Seals,” M.S. thesis, Texas A&M University, also available at Turbomachinery Laboratory, Report No.: TL-SEAL-3-88.
9.
Kilgore
J. J.
, and
Childs
D. W.
,
1990
, “
Rotordynamic Coefficients and Leakage Flow of Circumferentially Grooved Liquid-Seals
,”
ASME Journal of Fluids Engineering
, Vol.
112
, pp.
250
–
256
.
10.
Kim
C.-H.
, and
Childs
D. W.
,
1987
, “
Analysis for Rotordynamic Coefficients of Helically-Grooved Turbulent Annular Seals
,”
ASME JOURNAL OF TRIBOLOGY
, Vol.
109
(
1
), pp.
136
–
143
.
11.
Marquette, O. R., 1994, “A New Three-Control-Volume Theory for Circumferentially-Grooved Liquid Seals,” M.S. thesis, Texas A&M University, also available at Turbomachinery Laboratory, Report No.: TL-SEAL-11-94.
12.
Meirovitch, L., 1985, Introduction to Dynamics and Control, Wiley Interscience, New York.
13.
Nordmann, R., Dietzen, F. J., Janson, W., Frei, A., and Florjancic, S., 1986, “Rotordynamic Coefficients and Leakage Flow of Parallel Grooved Seals and Smooth Seals,” Rotordynamic Instability Problems in High-Performance Turbomachinery, NASA CP No, 2338, Proceedings of a Workshop held at Texas A&M University, pp. 129–153.
14.
Wyssman
H.
,
Pham
T.
, and
Jenny
R.
,
1984
, “
Prediction of Stiffness and Damping Coefficients for Centrifugal Compressor Labyrinth Seals
,”
ASME Journal of Engineering for Gas Turbines and Power
, Vol.
106
, pp.
920
–
926
.
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