• The KSFM Journal of Fluid Machinery
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• v.6 no.1 s.18
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• pp.14-22
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• 2003

In this paper the leakage prediction md rotordynamic analysis of an annular seal with a smooth rotor and spiral-grooved stator is performed. For the development of a theoretical model, the three-control-volume analysis of the circumferentially-grooved seal is expanded by considering pressure reduction due to the pumping effect of spiral groove and pressurized flow through the spiral groove. Validation on the present analysis is achieved by comparisons with available experimental data. For the leakage prediction the present analysis generally shows a reasonable agreement with experimental results. Rotordynamic coefficients for rotor speed with spiral angles show same trend, but the magnitudes of rotordynamic coefficients yield differences between analysis and experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.379.1-379
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• 2002

In this paper the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and spiral-grooved stator are performed. For developing a theoretical model, the three-control-volume analysis of the circumferentially-grooved seal is expanded by considering pressure reduction due to the pumping effect of spiral groove and pressure flow through the spiral groove. Validation to the present analysis is achieved by comparisons with available experimental data. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.799-804
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• 2002

In this paper the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and spiral-grooved stator are performed. For developing a theoretical model, the three-control-volume analysis of the circumferentially-grooved seal is expanded by considering pressure reduction due to the pumping effect of spiral groove and pressure flow through the spiral groove. Results by the present analysis are compared with available experimental data. For leakage the analysis results generally show a reasonable agreement to the experimental results. For rotordynamic coefficients the analysis results show the same trend as the experimental results for rotor speed with spiral angles, but their magnitudes show somewhat large deviations.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.1
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• pp.56-61
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• 1986

Rotor dynamic response of pumps is greatly influenced by the nature of the hydraulic forces arising from wearing seal, balance drum and impeller, etc.. Therefore, rotor dynamic analysis should be conducted during the design stage in order to aleviate some of the vibrational problems which might occur during the operational life of pumps. Previsousely, the authors have proposed the method to obtain the dynamic seal coefficients of the annular plain seal, convergent and divergent tapered seals, parallel grooved seal, spiral grooved seal and annular stepped seal. On the basis of these results, this paper presents the investigated effect of seals on the stability behavior of a centrifugal pump. The results show the effects of seal geometry, pressure difference, clearance, length/diameter ratio, on stability behavior.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.744-749
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• 2001

As related to rotordynamics, dynamic characteristics of the wear ring seal in high pressure multi-stage pump is calculated in the cases of labyrinth, damper and helically grooved types. The. results show that the labyrinth seal type has superior performance in the view point of leakage. However, in terms of rotordynamics view point, the damper seal type gains acceptable separate margin in critical speed range, while it has slightly inferior leakage performance compared to labyrinth seal type.

• Journal of KSNVE
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• v.7 no.6
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• pp.1015-1023
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• 1997

Rotordynamic analysis of a multistage turbine pump using finite element method is performed to investigate the effects of seal wear on its system behavior. Stiffness and damping coefficents of the 2-axial grooved bearing are obtained as functions of rotating speed. Stiffness and damping coefficients of plane annuler seals are calculated as functions of rotating speed as well as seal clearance of seals become larger, these stiffness and damping coefficients decrease drastically so that there can be significant changes in whirl natural frequencies and damping characteristics of the pump rotor system. Although a pump is designed to operate with a sufficient seperation margin from the 1st critical speed, seal wear due to long operation may cause a sudden increase in vibration amplitude by resonance shift and reduce seal damping capability.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.3
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• pp.285-291
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• 2014

This paper is related to the improvement of efficiency for high performance centrifugal pumps by reducing leakage loss, which is achieved by applying the grooved seal as a non-contact seal to the pumps. Various combinations of grooved seal types, including the spiral and the parallel groove in the rotor and/or in the stator, were tested by the experiment. And the corresponding hydraulic performance and the magnitude of axial thrust were measured and calculated for ten cases. From the results, the type with the spiral groove(spiral angle : $0.98^{\circ}$) in both the rotor and the stator was found to be most effective. In this case, the head and the efficiency were improved from the original design by 2.1% and 2.3% respectively at design capacity($340m^3/h$), and the axial thrust was decreased by 10%.

• Tribology and Lubricants
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• v.25 no.3
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• pp.150-156
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• 2009

Precise leakage prediction for annular type seals of turbomachinery is necessary for enhancing their efficiency and various prediction methods have been developed. As the seal passage is designed intricately, the analysis based on Bulk-flow concept which has been mainly used in predicting seal leakage is limited. In order to improve the seal leakage prediction, full Navier-Stokes Equations with turbulent model derived in the seal flow passage have to be solved. In this study, 3D CFD (Computational Fluid Dynamics) analysis has been performed for predicting leakage of various non-contact type anular seals using FLUENT. Compared to the results by Bulk-flow model analysis, experiment, and 2D CFD analysis, the result of 3D CFD analysis shows improvement in predicting seal leakage, especially for the parallel grooved pump seal.

• Journal of Mechanical Science and Technology
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• v.14 no.3
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• pp.261-271
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• 2000

In this paper the leakage prediction and rotordynamic analysis of an annular seal with a smooth rotor and circumferentially grooved stator are performed based on a three-controlvolume theory. The present analysis is validated by comparing with the experimental data of Iwatsubo and Sheng and theoretical results suggested by Marquette and Childs. For the leakage prediction the present analysis shows a good agreement with Marquette and Childs' result and a qualitation agreement with Iwatsubo and Shengs' experimental data. Direct and cross-coupled stiffness coefficients show closer agreement with the experimental values than those of Marquette and Childs. However, direct damping coefficient shows greater discrepancy from the experimental value than Marquette and Childs'.

• 유체기계공업학회:학술대회논문집
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• 1998.02a
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• pp.203-209
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• 1998

Rotordynamic analysis of a multistage turbine pump using finite element method is performed to investigate the effects of seal wear on Its system behavior. Stiffness and damping coefficients of the 2-axial grooved bearing are obtained as functions of rotating speed. Stiffness and damping coefficients of plane annular seals are calculated as functions of rotating speed as well as seal clearance. As the clearance of seals become larger, these stiffness and damping coefficients decrease drastically so that there can be significant changes in whirl natural frequencies and damping characteristics of the pump rotor system. Although a pump is designed to operate with a sufficient seperation margin from the 1st critical speed, seal wear due to long operation may cause a sudden increase in nitration amplitude by resonance shift and reduce seal damping capability.