Reliable high-speed data are presented for leakage and rotordynamic coefficients of a plain annular seal at centered and eccentric positions. A seal with L/D = 0.45 was tested, and measured results have good signal-to-noise ratios. The influence on rotordynamic coefficients of pressure drop, running speed, and static eccentricity was investigated. There is an excellent agreement between experimental and theoretical results in the centered position, even for direct inertia terms, which have not shown good agreement with predictions in past studies. However, the rotordynamic coefficients are more sensitive to changes in eccentricity than predicted. These results suggest that, in some cases, annular seals for pumps may need to be treated more like hydrodynamic bearings, with rotordynamic coefficients which are valid for small motion about a static equilibrium position versus the present eccentricity-independent coefficients.

Childs, D. W., and Hale, R. K., 1993, “A Test Apparatus and Facility to Identify the Rotordynamic Coefficients of High-Speed Hydrostatic Bearings,” ASME JOURNAL OF TRIBOLOGY, Vol. 48.
Childs, D. W., 1993, Turbomachinery Rotordynamics: Phenomena, Modeling, and Analysis, Wiley Interscience, New York.
Falco, M., Mimmi, G., and Marenco, G., 1986, “Effects of Seals on Rotor Dynamics,” Proceedings of the IFToMM International Conference on Rotordynamics, Tokyo, Japan, pp. 655–662.
Graf, K., and Staubli, T., 1990, “Comparison of Two Identification Models for Rotordynamic Coefficients of Labyrinth Seals,” Interfiuid, First International Congress on Fluid Handling Systems, Essen, Germany.
Kanki, H., and Kawakami, T., 1984, “Experimental Study on the Dynamic Characteristics of Pump Annular Seals,” Vibrations in Rotating Machinery, Proceedings of the Third IMechE International Conference on Vibrations in Rotating Machinery, York, England, pp. 159–166.
Lindsey, W. T., and Childs, D. W., 1995, “The Effects of Converging and Diverging Axial Taper on the Rotordynamic Coefficients of Liquid Annular Pressure Seals: Theory Versus Experiment,” accepted for the 1995 ASME Vibration Conference, Sept. 17-21, Boston, MA.
Lund, J., 1965, “The Stability of an Elastic Rotor in Journal Bearings with Flexible, Damped Supports,” ASME Journal of Applied Mechanics, pp. 911–920.
Marquette, O., 1995, “Experimental Versus Theoretical Comparison of the Static and Dynamic Characteristics of One Smooth and Two Grooved Liquid Annular Seals with L/D of 0.457,” TL-SEAL-5-95, Turbomachinery Laboratory, Texas A&M University.
San Andres, L., 1991, “Analysis of Variable Fluid Properties, Turbulent Annular Seals,” ASME JOURNAL OF TRIBOLOGY, pp. 694–702.
This content is only available via PDF.
You do not currently have access to this content.